CRUISE REPORT: TransArc 
(updated APR 2019)










Highlights 

                          Cruise Summary Information

               Section Designation  TransArc  
Expedition designation (ExpoCodes)  06AQ20110805 (ARK-XXVI/3)  
                  Chief Scientists  Ursula Schauer/AWI  
                             Dates  2011 AUG 05 -2011 OCT 06  
                              Ship  R/V Polarstern  
                     Ports of call  Tromsø, Norway - Bremerhaven, Germany  

                                                  89°57'52.2" N 
             Geographic Boundaries  177°28'5.5" W               177°26'55.68" E 
                                                  76°10'37.2" N  

                          Stations  111 CTD Stations  
      Floats and drifters deployed  11 Drifting buoys, 3 Ice-anchored buoys  
    Moorings deployed or recovered  5 deployed, 3 recovered  



                               Contact Information: 

                              Prof. Leif G. Anderson
             Department of Marine Sciences University of Gothenburg
                            SE-412 96 Göteborg Sweden
                            Email: leifand@chem.gu.se 














                  Report assembled by Jerry Kappa, UCSD/SIO 




Berichte                                                           649
zur Polar-                                                        2012
und Meeresforschung


                     Reports
on Polar and Marine Research 


The Expedition of the Research Vessel "Polarstern"  
to the Arctic in 2011 (ARK-XXVI/3 - TransArc) 


Edited by 
Ursula Schauer 
with contributions of the participants 





HELMHOLTZ                                  ALFRED-WEGENER-INSTITUT FÜR  
 | GEMEINSCHAFT                             POLAR- UND MEERESFORSCHUNG 
                                         in der Helmholtz-Gemeinschaft 
                                                   D-27570 BREMERHAVEN 
                                            Bundesrepublik Deutschland 


                                                           ISSN 1866-3192 


Hinweis                               Notice 

Die Berichte zur Polar- und           The Reports on Polar and
Meeresforschung werden vom            Marine Research are issued
Alfred-Wegener-Institut für           by the Alfred Wegener Institute
Polar- und Meeresforschung            for Polar and Marine Research
in Bremerhaven* in unregelmäßiger     in Bremerhaven*, Federal Republic
Abfolge herausgegeben.                of Germany. They are published
                                      in irregular intervals.
Sie enthalten Beschreibungen und 
Ergebnisse der vom Institut (AWI)     They contain descriptions and
oder mit seiner Unterstzung           results of investigations in
durchgefrten Forschungsarbeiten       polar regions and in the seas
in den Polargebieten und in den       either conducted by the Institute
Meeren.                               (AWI) or with its support.

Es werden verfentlicht:               The following items are published:

- Expeditionsberichte                 - expedition reports (incl.
  (inkl. Stationslisten und             station lists and route maps)
  Routenkarten) 

- Expeditions- und                    - expedition and research results
  Forschungsergebnisse (inkl.           (incl. Ph.D. theses)
  Dissertationen) 

- wissenschaftliche Berichte der      - scientific reports of research
  Forschungsstationen des AWI           stations operated by the AWI

- Berichte wissenschaftlicher         - reports on scientific meetings
  Tagungen 


Die Beitrge geben nicht               The papers contained in the Reports
notwendigerweise die Auffassung       do not necessarily reflect the
des Instituts wieder.                 opinion of the Institute.

     
  
               The "Brichte zur Polar- und Meeresforschung"
             continue the former "Brichte zur Polarforschung"    




* Anschrift / Address                 Editor:  
Alfred-Wegener-Institut               Dr. Horst Bornemann  
für Polar- und Meeresforschung  
D-27570 Bremerhaven                   Assistant editor:  
Germany                               Birgit Chiaventone  
www.awi.de  








—————————————————————————————————————————————————————————————————————————
Die "Berichte zur Polar- und Meeresforschung" (ISSN 1866-3192) werden ab 
2008 als Open-Access-Publikation herausgegeben (URL: http://epic.awi.de). 

Since 2008 the "Reports on Polar and Marine Research" (ISSN 1866-3192) 
are available as open-access publications (URL: http://epic.awi.de) 
—————————————————————————————————————————————————————————————————————————








The Expedition of the Research Vessel "Polarstern"  
to the Arctic in 2011 (ARK-XXVI/3 - TransArc) 



—————————————————————————————————————————————————————————————————————————

Edited by 
Ursula Schauer 
with contributions of the participants 



Please cite or link this publication using the identifier 
hdl: 10013/epic.39934 or http://hdl.handle.net/10013/epic.39934 

ISSN 1866-3192 









                          ARK-XXVI/3 - TransArc
                        5 August - 6 October 2011
                           Tromsø - Bremerhaven





                      Fahrtleiter / Chief Scientist
                              Ursula Schauer






                         Koordinator / Coordinator
                            Eberhard Fahrbach










Contents 


1.   Zusammenfassung und Fahrtverlauf                                   6
     Summary and Itinerary                                              9

2.   Weather Conditions                                                12

3.   Sea Ice Physics                                                   15

     3.1  Airborne sea ice thickness surveys                           16

     3.2  Optical measurements                                         19

     3.3  Ice station work and ice cores                               27

     3.4  Deployment of drifting buoys                                 34

     3.5  Routine sea ice observations 50                              36

     3.6  References                                                   39

4.   Physical Oceanography                                             40

5.   Geochemistry                                                      49

     5.1  The carbonate system                                         49

     5.2  Radium and Thorium isotopes                                  59

     5.3  Tracing terrestrial carbon across the Arctic shelf 
          and slope                                                    61

     5.4  7Be as tracer for determining atmospheric deposition         
          of trace elements                                            62

     5.5  Net community productivity using dissolved O2/Ar/222Rn       63

     5.6  Mercury cycling in the Arctic 106                            67

     5.7  Distribution of 236U and of Cs isotopes                      68

6.   Biogeochemistry                                                   69

7.   Marine Biology                                                    71

     7.1  Biology of sea-ice and related ecosystems                    71

     7.2  Plankton Ecology and Biogeochemistry in a Changing           
          Arctic Ocean (PEBCAO)                                        78

     7.3  Zooplankton investigations                                   81


8.   Marine Geology                                                    87

     8.1  Multi-beam bathymetry                                        88

     8.2  Marine sediment echosounding using Parasound                 91

     8.3  Sediment cores                                               96




Appendix 


A.1  Beteiligte Institute / participating institutes                  107 

A.2  Fahrtteilnehmer / participants                                   108

A.3  Ship's crew                                                      110

A.4  Stationsliste /station list PS78                                 111
 



1.  ZUSAMMENFASSUNG UND FAHRTVERLAUF 

    Ursula Schauer                          Alfred-Wegener-Institut 

Die Polarstern-Expedition ARK-XXVI/3 "TansArc" (Trans-Arctic survey of 
the Arctic Ocean in transition) diente dem übergeordneten Ziel, den 
physikalischen, biologischen und chemischen Zustand des Arktischen Ozeans 
im Klimawandel zu erfassen. Whärend der Rükgang der Meereisausdehnung 
kontinuierlich durch Satellitenfernerkundung überwacht werden kann, 
müssen Veränderungen aller anderen Parameter wie der Dicke und weiterer 
Charakteristiken des Meereises, der Eigenschaften und der Zirkulation von 
Wassermassen sowie der chemischen Substanzen und der kosysteme durch 
wiederholte Expeditionen mit dem Schiff oder durch autonome Plattformen 
erfasst werden. Vor diesem Hintergrund fand mit "TansArc" vier Jahre nach 
dem Internationalen Polarjahr (IPY 2007/2008) die erste umfassende 
Aufnahme der Bedingungen im zentralen Arktischen Ozean statt. 

Die Abnahme des mehrjährigen Eises hat Auswirkungen auf die 
Ozeanzirkulation und damit auf die Eigenschaften der Wassermassen und die 
Stabilität des Arktischen Ozeans. Diese werden durch den Einstrom aus dem 
Atlantik und dem Pazifik, sowie durch die immensen Festlandsabflüsse 
bestimmt. Die Variabilität dieser Komponenten, wie etwa die Erwärmung des 
Einstroms aus dem Atlantik und dem Pazifik und die starke Akkumulation 
von Süßwasser in den letzten beiden Dekaden beeinflussen zusammen mit der 
Eisabnahme den Gasaustausch mit der Atmosphäre, chemische Flüsse sowie 
Ökosysteme und die mit ihnen verknüpften biogeochemischen Kreisläufe im 
Eis und in der gesamten Wassersäule. Die Zirkulationsänderungen wirken 
sich auch auf den Nordatlantik aus. 

Die Wirkung der Advektion und die Eisbedingungen bedingen große räumliche 
Kontraste. Um mehrjährige oder dekadische Veränderungen zu erkennen, 
müssen räumliche und zeitliche Signale klar voneinander getrennt werden, 
was im schwer zugänglichen Arktischen Ozean eine größere Herausforderung 
ist als in eisfreien Meeren. 

Während TransArc beprobten wir auf multidisziplinären Stationen Eis- und 
Ozeaneigenschaften und die entsprechenden Ökosysteme entlang von 
Gradienten von den Eurasischen Schelfmeeren bis ins Kanadische Becken. 
Dabei wurden die Atlantischen Einstromzweige durch die Framstraße und die 
Barentssee ebenso abgedeckt wie die Ausbreitung des Süßwassers aus 
sibirischen Flüssen und die Verteilung des einströmenden Pazifikwassers. 
Gleichzeitig erstreckten sich die Schnitte vom offenen Wasser über 
einjähriges bis ins dichte mehrjährige Eis. Während der 1990er und der 
2000er Jahre wurden Vorläufer dieser Schnitte auf Expeditionen mit der 
Oden und der Polarstern schon einmal beprobt. Um den Beobachtungsradius 
räumlich und zeitlich zu erweitern, wurden physikalische und biologische 
Messungen durch eine Reihe von eisgetragenen Bojen und 3 
Bodenverankerungen ergänzt. Bei vielen Arbeiten wurden Hubschrauber 
eingesetzt: für Messflüge mit der Eisdickensonde, zum Personentransport 
zur Beprobung von entfernteren Eisschollen und zur Eiserkundung für 
nautische Zwecke. 

Zwei Ereignisse verliehen dieser Expedition eine besondere Note: Das 
Erreichen des Nordpols am 22. August und der Besuch der russischen 
Driftstation NP-38. Beide Ereignisse wurden durch die gstigen 
Eisbedingungen sehr erleichtert. Polarstern erreichte auf dieser Reise 
den Nordpol zum dritten Mal, nachdem dies bereits 1991 während ARK-VII/3 
und 2001 während ARK-XVII/2 erfolgt war. Im Gegensatz zu den ersten 
beiden Malen fuhren wir nun ohne Begleitung durch ein anderes Schiff zum 
Nordpol, ein deutlicher Hinweis auf die schon jetzt erheblich 
erleichterte Schiffbarkeit der Arktis. 

Bedauerlich war, dass wir innerhalb der russischen ausschließlichen 
Wirtschaftszone (EEZ), und damit am Kontinentalhang und in den 
Schelfmeeren nur sehr eingeschränkt arbeiten durften. Lediglich die 
Messung physikalischer Parameter und der Konzentration einiger gelöster 
Gase sowie die Beprobung von Plankton und Aerosolen war zugelassen 
worden. 

Polarstern lief pktlich am 5. August 2011 aus Tromsø aus. Es waren 54 
Wissenschaftler aus zehn Instituten aus sieben Ländern und 43 
Besatzungsmitgliedern an Bord. Nach dem Passieren der Barentssee 
erreichten wir am 9. August nrdlich von Franz-Josef-Land den Eisrand und 
begannen unsere Arbeit mit CTD- und Netzstationen auf einem Schnitt nach 
Norden entlang von 60°E. Am Kontinentalabhang bargen wir eine Verankerung 
des russisch-amerikanischen Programms NABOS (Nansen and Amundsen Basins 
Observational System). Keiner der beiden akustischen Auslöser 
funktionierte, aber mit einem ausgeklügelten Dredgeverfahren konnten wir 
im lockeren Eis Verankerungsmaterial und zwei Jahre wertvoller Daten 
bergen. Am 11. August gab es die erste Eisstation für Eisdicken- und 
optische Messungen, gefolgt vom ersten Einsatz eines Untereis-ROVs 
(Remotely Operated Vehicle) am 17. August. Den Gakkelrücken überquerten 
wir in einem Gebiet, wo vor 20 Jahren schon einmal Sedimentproben 
genommen worden waren; an diesen Lokationen nahmen wir wieder 
Sedimentproben, um eventuelle Veränderungen im Benthos zu erfassen. 

Das mürbe Eis machte es schwer, geeignete Schollen für die Eisarbeit zu 
finden. Aber es ermlichte uns, unseren Kurs nach Norden fast ungehindert 
fortzusetzen. So erreichten wir am 22. August den Nordpol und feierten 
dieses Ereignis. Ermutigt durch das gute Fortkommen setzten wir unseren 
Kurs fort und überquerten den Lomonossowrken. Wir wagten uns sogar noch 
weiter nach Osten, um auf dem wenig erkundeten Alpharken bathymetrische 
Aufnahmen durchzuführen und Sedimentkerne zu ziehen. Allerdings kamen wir 
hier im dicken Packeis nördlich von Ellesmere Island bald nicht mehr 
weiter und bei 88°55'N, 115°W beschlossen wir am 25. August unseren Kurs 
nach Westen ins Makarowbecken zu nehmen. Schnell besserten sich die 
Eisbedingungen und so bogen wir ein weiteres Mal nach Süden ab, um weit 
ins Kanadische Becken vorzudringen. Nach dem Passieren des magnetischen 
Pols am 31. August nahe 85°04'N, 137°14'W berquerten wir den 
Mendelejewürken und erreichten das Kanadische Becken. Dort beprobten wir 
auf etlichen Eis- und Wasserstationen den pazifisch beeinflussten Teil 
des Arktischen Ozeans. Unsere sdlichste Station in diesem Gebiet 
erreichten wir am 3. September. In lockerem Eis dampften wir anschließend 
nordwestwrts, um am 6. September die russische Eisstation NP-38 zu 
treffen. Dort übernahmen wir Ausrtungsmaterial einer führeren deutschen 
Beteiligung und nutzten das Treffen zu gegenseitigen Besuchen. Wir waren 
sehr beeindruckt von dem guten Mut und der herzlichen Gastfreundschaft 
unserer russischen Kollegen, die das Beobachtungsprogramm von ihrem 
kleinen Camp aus immerhin bereits seit einem Jahr ununterbrochen 
durchführten. 

Von NP-38 aus ging es weiter nach Westen für einen zweiten langen Schnitt 
zum sibirischen Schelf. Dieser Schnitt bot uns eine letzte Chance, 
Eisbojen auszubringen. Aber die Suche nach geeigneten stabilen, d.h. 
hinreichend dicken und großen Schollen gestaltete sich zunehmend 
schwierig, da es kaum noch mehrjähriges Eis im östlichen Sektor der 
eurasischen Arktis gab. Am 8. September fanden wir eine passende Scholle 
für das, was wir die "Super Buoy Station" nannten. Hier installierten wir 
eine Kombination verschiedener Bojen, die unterschiedlichste Sensoren 
trugen, um eine möglichst multidisziplinäre Aufnahme im Eis und im Ozean 
am gleichen Ort zu ermöglichen. Nebenbei wurde natülich auch das übliche 
umfangreiche Eisstationsprogramm durchgeführt, aber das mürbe Eis, 
schneebedeckte Schmelztümpel und ein starker Schneesturm wiesen uns die 
Grenzen für Arbeiten in der Arktis auf, die selbst im Sommer bestehen. 

Zurück im Eurasischen Becken verankerten wir zwei Gruppen von 
Bodenverankerungen für Aufnahmen ozeanographischer und biologischer 
Parameter. Die Verankerungen sollen 2012 während der Polarsternexpedition 
"IceArc" wieder aufgenommen werden. Obwohl wir auf unserem Weg in Richtung 
Severnaja Zemlja schon nahe des Eisrands entlangfuhren, lieen uns 
Informationen über die Eisbedeckung, die wir täglich aus Bremen 
erhielten, noch einmal auf ein Gebiet mit konsolidiertem Eis hoffen. In 
der Tat konnten wir am 16. September unsere letzte Eisstation 
durchführen. 

Der lange Schnitt endete an der Schelfkante. Er wurde noch durch drei 
weitere kurze Schnitte er den Kontinentalabhang mit Hydrographie und 
Netzfängen - und außerhalb der russischen EEZ auch mit Sedimentproben - 
ergänzt, so dass wir insgesamt den Randstrom vom Zusammenfluss des 
atlantischen Wassers aus der Framstraße mit dem aus der Barentssee bis 
zur abermaligen Verzweigung des Randstroms nördlich der Laptewsee 
aufgenommen haben. Am 21. September wurden zwei weitere Verankerungen des 
NABOS-Programms aufgenommen; eine davon enthielt Daten über vier Jahre. 
Bei beiden versagte wieder die Auslösertechnik und wieder machten nur 
höchstes nautisches und mannschaftliches Geschick die Bergung möglich. 

Den Abschluss des Forschungsprogramms bildeten Schnitte in der flachen 
Laptewsee, die vorangegangene Arbeiten eines deutsch-russischen Programms 
ergänzten. Die letzte Station erfolgte am 26. September bei 77°12' N, 
112°51' E. Nach der Rückfahrt durch die eisfreie Nordostpassage und die 
stmische Norwegische See und die Nordsee lief Polarstern am 6. Oktober 
2011 in Bremerhaven ein. 


Fig. 1.1: Cruise track during "TransArc"
Abb. 1.1: Fahrtroute von "TransArc"

Fig. 1.2: Map of stations taken during “TransArc”. Bottom topography from 
          U.S. Department of Commerce, National Oceanic and Atmospheric 
          Administration, National Geophysical Data Center, 2006. 2-
          minute Gridded Global Relief Data (ETOPO2v2.) 
Abb. 1.2: Karte der Stationspositionen von "TansArc". Bodentopographie 
          von U.S. Department of Commerce, National Oceanic and 
          Atmospheric Administration, National Geophysical Data Center, 
          2006. 2-minute Gridded Global Relief Data (ETOPO2v2.) 



SUMMARY AND ITINERARY 

The Polarstern expedition ARK-XXVI/3 “TransArc” (Trans-Arctic survey of 
the Arctic Ocean in transition) served the overarching goal to capture 
the physical, biological and chemical state of the Arctic Ocean in a 
changing climate. While the decrease of the sea ice extent can be 
monitored by satellite remote sensing, changes of all other oceanic 
parameters in the Arctic, such as thickness and other characteristics of 
sea ice, water mass properties and circulation as well as chemical 
constituents and biota need to be measured during repeated ice breaker 
cruises or from autonomous platforms. Hence, four years after the 
International Polar Year (IPY 2007/2008), “TransArc” constituted the 
first repeat survey of the central Arctic Ocean. 

The water masses and the stability of the Arctic Ocean are largely 
conditioned by the inflow of waters from the Atlantic and Pacific Oceans 
and of huge amounts of fresh water from land. The ocean circulation and 
the shrinking of the multiyear ice are closely linked. Variations of 
these components, such as the accumulation of fresh water in the central 
Arctic and the warming of the Atlantic and Pacific inflows in the last 
decade, will affect also substance distribution and ecosystems. Together 
with the ice retreat they affect the gas exchange with the atmosphere, 
chemical fluxes as well as the ecosystems and the related biogeochemical 
cycling in the sea ice and in the entire water column. The Arctic 
circulation changes have also impact on the North Atlantic. 

Due to advection and the ice cover significant spatial gradients are 
present in the Arctic Ocean. To distinguish between decadal or shorter- 
term variability and long-term change one has to ensure a separation 
between spatial and temporal variations which is more difficult in the 
sparsely observed Arctic than in open oceans. 

During TransArc we sampled the ocean and ice properties and their 
ecosystems along gradients from the Eurasian shelf edge to the Canadian 
Basin. This multidisciplinary effort captured the Atlantic water inflows 
through both Fram Strait and Barents Sea, as well as the spreading of 
Siberian river-runoff and of Pacific Water. At the same time the sections 
occupied the transition from the ice-free ocean through first-year ice to 
the multi-year pack ice and back again. The expedition repeated large-
scale sections that were captured in the 1990s and early this century by 
e.g. Oden and Polarstern, thus permitting comparability. To extend the 
observation range and to obtain year-round observations of physical and 
biological parameters of ice and ocean a number of ice-tethered buoys and 
bottom-mounted moorings were deployed and recovered respectively. Many 
tasks were carried out or supported by helicopter flights, like missions 
with the ice thickness sensor, transfer of researchers for sampling at 
remote ice floes and ice reconnaissance flights for nautical purposes. 

Two events made this cruise a special one: One was the visit of the North 
Pole on 22 August, the other was the visit of the Russian drifting 
station NP38. Both events were facilitated by the very favorable ice 
conditions. The visit of the North Pole was the third time for Polarstern 
after her first visit in 1991 (ARK-VIII/3) and a second visit in 2001 
(ARK- XVII/2). It was however the first North Pole visit without any 
accompanying vessel, accentuating the transition towards easier shipping 
conditions in the Arctic Ocean. 

Unfortunately, within the Russian Exclusive Economic Zone (EEZ), i.e. at 
the continental slope and in the shelf seas, the investigations were 
considerably restricted and sampling was only possible for physical 
parameters, some dissolved gas compounds, phyto- and zooplankton content 
of the water column and of the sea ice, and the aerosol content of the 
near-surface atmosphere. 

Polarstern left Tromsø August 5, 2011, with 54 scientists from 10 
institutes of 7 countries and 43 crew members on board. After passing the 
Barents Sea, we reached the ice edge north of Franz Josef Land on August 
9 and started our work with a northward transect along 60E taking water 
property and plankton net casts. At the continental slope of the Nansen 
Basin we recovered a mooring belonging to the Russian-American program 
NABOS (Nansen and Amundsen Basins Observational System). Both acoustic 
releasers of the mooring failed, but, fortunately, the ice conditions 
were moderate so that the mooring could be recovered with a sophisticated 
dredging maneuver. On August 11 the first ice station was carried out for 
thickness and optical measurements which was followed on August 17 by the 
first deployment of a ROV for under ice observations. At the Gakkel 
Ridge, a couple of sites were revisited where surface sediment has been 
sampled 20 years ago during Polarstern cruise ARK-VIII/3, and now 
replicate cores were taken to study benthos variability. 

The crumbled state of the ice, making it, on one hand, difficult to find 
suitable floes for ice stations, enabled us on the other hand to continue 
steaming and working along 60°E up to the North Pole, which was reached 
on August 22 and prompted a celebration. Encouraged by the good progress 
we continued the transect across the Lomonosov Ridge and even turned east 
to survey and take sediment cores in the poorly charted regions of the 
Alpha Ridge. However, we did not get very far before finally reaching 
heavy pack ice so that we decided on August 25 at 88°55'N, 115°W to turn 
westward into the Makarov Basin. Soon the ice became smoother and we 
turned once more south to get far into the Canadian Basin. Passing the 
Magnetic Pole on 31 August near 85°4'N, 137°14'W, we crossed the 
Mendeleyev Ridge into the Canada Basin and, capturing several water and 
ice stations in the Pacific Water regime, reached our south-easternmost 
station on September 3. In moderate ice conditions we then sailed 
westward to meet the Russian drifting station NP-38 on September 6, where 
material from a former German participation was taken over. The day was 
used for visits in both directions and we were very much impressed by the 
good mood and the great hospitality of the Russian colleagues who have 
been carrying out observations in their little camp throughout a whole 
year. 

From NP-38, located then at the Mendeleyev Ridge, we headed westward to 
conduct a second-long cross-basin section towards the Siberian shelf. 
This section brought us a last chance to deploy various ice buoys; yet, 
the search for appropriate, i.e. large and thick, ice floes became more 
and more difficult, because hardly any multiyear ice was left in eastern 
Eurasian Arctic. On September 8, we found a suitable floe for what we 
called our "Super buoy station" where we installed a multitude of buoys 
carrying various sensors for sea ice, ocean and biooptical properties. 
There, of course, we also carried out extensive sea ice investigations. 
However, the mushy ice surface, snow-covered melt ponds and a heavy snow 
storm made this station a challenge for everybody working on the ice and 
on the bridge. 

Back in the Eurasian Basin, two ensembles of moorings for year-round 
oceanographic and biologic recordings were deployed on either side of the 
Gakkel Ridge which will be recovered in 2012 with Polarstern during 
"IceArc" Although we had already passed the ice edge on our way towards 
Severnaya Zemlya, information of the sea ice concentration that we 
obtained daily from the University Bremen indicated a patch of 
consolidated multi-year sea ice ahead of us. This enabled us to plan and 
conduct the last ice station of the cruise on September 16. 

The long section was conducted up the continental slope, and three 
additional short cross-slope sections with CTD stations, plankton net 
casts and, outside of the Russian EEZ, also sediments samples completed a 
series of transects, capturing the boundary current of Atlantic Water 
from the confluence of the Fram Strait and the Barents Sea branches up to 
the re-splitting of the boundary current off the Laptev Sea. In between, 
two more moorings of the NABOS program were recovered on September 21, 
both requiring once again highest dredging skills because of identical 
technical failure of the releasers. The last part of the working program 
augmented a hydrographic survey in the Laptev Sea of the German Russian 
program "Laptev Sea system". 

The station work finished on September 26 at 77 11.69' N, 112 50.61' E. 
After passing the ice-free Northern Sea Route to the western Barents Sea 
and the stormy Norwegian and North Seas, Polarstern returned to 
Bremerhaven on 6 October 2011. 




2.  WEATHER CONDITIONS 

    Harald Rentsch, Hartmut Sonnabend       Deutscher Wetterdienst 


On August 5 (18:00 ship's time) RV Polarstern left the port of Tromsø at a 
nearly calm sea and broken skies. After leaving the fjords we got 
northerly winds of force 6 Beaufort (Bft) and a sea of 2 to 3 m. This was 
caused by the pressure field with an anticyclone over Greenland (maximum 
pressure around 1020 hPa) and a low east of Novaya Zemlya which moved 
westward. A covered sky and north-easterly winds of Bft 6-7 accompanied 
us up to the first working-station north of Franz Joseph Land where we 
also reached the ice edge on the fourth day of our journey. 

During our transect along 60°E which we started on August 10, 2011, we 
passed a cyclone which moved from the Kara Sea towards Svalbard. 
Thereafter the wind reached 6-7 Bft. The associated rain, snow and fog 
did not affect the ship-based work but prevented helicopter flights for 
two days. Only on August 12 stronger winds coming from the lee side of 
Franz Joseph Land mountains provided us with good flight conditions. 

Before the ship entered the region of the dynamical Arctic anticyclone 
near the North Pole, weak low-pressure systems (polar lows) dominated 
with fog, precipitation (mostly rain) and low clouds and inhibited 
helicopter-flights with the EM-Bird. However, despite very low ceiling 
and visibility, flights for ice reconnaissance could be realized.  
Occasionally, on August 16, 17 and 18 we got sunny periods at the back 
side of fronts in connection with nearly 100% sea ice cover.  These short 
time spans were used for flights with EM-Bird and X-CTD-launches. Before 
we reached the North Pole the flight conditions were usually bad (see 
Fig. 2.3 and 2.4). 


Fig. 2.1: NOAA-19 satellite picture during crossing North Pole of 
          Polarstern (ship's call sign DBLK), August 22, 2011, 7:58 utc. 


When we reached the North Pole at August 22, 2011, 07:42 UTC (see Fig. 
2.1), a high-pressure system over the Barents Sea brought moist, warm and 
stably layered air towards our cruise track. This caused fog and often 
very low clouds with icing conditions preventing long-range helicopter 
flights. Only short (40 miles) flights for ice reconnaissance were 
possible. 

A trough on the surface passing the North Pole on August 23, 2011 changed 
the general weather situation completely. Further on, north-easterly 
winds advecting moist, cold air from the Laptev Sea brought often snow 
showers. Helicopter flights for scientific purposes could be done. 

During the next four days an anticyclone near the North Pole caused a 
stable stratification in the lower atmosphere. Supported was this state 
by a nearly closed sea-ice cover and dryer air flow from northeast of 
wind force 5 Bft. 

The precipitation-free period ended on August 27 with the arrival of a 
polar low which brought light snowfall. During the following days low 
clouds, snow and fog patches reached us together with weak fronts that 
developed in the Laptev Sea and spread northward. At calm north winds and 
low clouds helicopter flights were restricted. 

Between August 30 and September 1, we met the first complex low-pressure 
system on this expedition (lowest pressure 1005 hPa) bringing snowfall 
and low-level clouds. The system moved from Chuckchi Sea towards 
Greenland passing our operation area. Icing in combination with rain and 
snow inhibited again helicopter flights. Changing wind directions near 
the centre of the low and bad visibility did not make it easier for 
navigation of the research vessel through compact multi-year ice. 

On September 2 we reached the back side of the low and got westerly 
winds, low clouds and temperatures below 0°C and most helicopter-based 
tasks could be carried out. 

On September 6 when we met the Russian ice-drifting station NP38, a 
nearby front caused weak snowfall and easterly wind of force 4 Bft. 


Fig. 2.2: NOAA-16 satellite picture, September 10, 2011, 03:42 utc; 
          Extended gale force low (L) nearby Polarstern (DBLK), course 
          Laptev Sea; maximum gusts 90 cross from stew port side: 47 
          Knots. 


This weather enabled numerous shuttle flights per helicopter between the 
ship and "NP38". After a weak polar low had crossed our ship's track on 
September 7, a well-structured front of a low centred at 86N 80W brought 
us strong south-westerly winds of force 6 to 7 Bft and snowfall due to 
gliding of warmer over colder air masses, which prevented flights for 
that day. 

From September 9 to 11 a low (lowest pressure 980 hPa, Fig. 2.2) situated 
over the Lomonosov Ridge and moving towards the Canada Basin caused 
continuous snowfall and brought us one of the rare occasions of high wind 
speed (force 8 to 9 Bft from stew port side) and with -10°C the lowest 
temperatures of our cruise (see the statistics in Fig. 2.5). The strong 
wind and the low temperatures caused a wind-chill temperature of -35°C. 
Due to the bad visibility without any contrast and horizon, called "white 
out", which is typical for overcast skies and snow-covered sea ice, all 
helicopter flights had to be cancelled. The northerly winds pushed the 
ice towards south, and the more open ice-cover enabled easier sailing for 
the ship. 

At September 12, a ridge of high pressure with weak and dry wind spread 
into our working area and brought us very good flight conditions. This 
situation caused, at 14:51 ship's time, the greatest sunset of this 
cruise. However, on September 13 a new low and its snowfall moving from 
the New Siberian Islands towards southeast reached our ship's track. 

From September 14 to 16 we passed the edge of a ridge of high pressure 
and had cold north-westerly, later north-easterly wind at force 5 Bft and 
large fields of low clouds but also some sunny spells, conditions which 
again restricted helicopter flights. Only in the night from September 16 
to 17, at the last sea-ice station, southerly winds caused by lee-effects 
from mountains of Severnaya Zemlya produced clear sky and enabled last 
flights with the EM-Bird. 

After that, warm air with temperatures above 0C arrived from Laptev Sea 
which caused fog when it met the ice. This situation prevented helicopter 
flights. Later a well-structured cold front from the central Arctic 
brought cold air and light snow showers but also good visibility. 
Northerly wind on the eastern side of a strong high-pressure system over 
Barents Sea led the temperatures drop to -5°C. Some upper troughs raised 
the wind velocity for short time so that a swell up to 2 m was observed 
at our passage of the Gakkel Ridge. 

When we arrived in the open Laptev Sea, the sea-surface temperatures were 
up to 3°C. At the same time cold air was pushed from the central Arctic 
towards south causing intense snow showers until September 25. Until the 
end of our work one day later we remained under the influence of a high-
pressure system over Barents Sea bringing north-westerly wind and wave 
heights up to 2.5 m. 

On our way through the ice-free Kara and Barents Sea we faced weak 
westerly winds near a ridge of high pressure and at times fog until 
September 29. 

When we passed the North Sea heading for Bremerhaven our weather was 
dominated by storms. With the help of the exact forecasts for our planned 
ship track we were able to circumnavigate the highest waves and the 
windiest situations and thus reached Bremerhaven safely one day earlier 
than planned. 

The wind and temperature conditions during the cruise are displayed in 
figures 2.5 to 2.7. 


Fig. 2.3: Distribution of ceiling, August 10 to September 19, 2011, along 
          Polarstern's (DBLK) cruise track in ice covered seas.

Fig. 2.4: Distribution of visibility, August 10 to September 19, 2011, 
          along Polarstern's (DBLK) cruise track in ice covered seas.

Fig. 2.5: Distribution of wind force along Polarstern's (DBLK) cruise 
          track during scientific station work from August 07 to 
          September 26, 2011.

Fig. 2.6: Distribution of wind direction along Polarstern's (DBLK) cruise 
          track during scientific station work from August 07 to 
          September 26, 2011.

Fig. 2.7: Time series of air temperature along Polarstern's (DBLK) cruise 
          track during scientific station work from August 07 to September 
          26, 2011. 





3.  SEA ICE PHYSICS 

    Stefan Hendricks, Marcel Nicolaus,      Alfred-Wegener-Institut 
    Robert Ricker, Mario Hoppman, 
    Priska Hunkeler, Christian Katlein 


Introduction 

Satellite observations reveal a reduction of Arctic summer sea ice extent 
in the order of 8% per decade. This reduction is accompanied by a 
decrease of ice age, leaving a smaller, younger and subsequently thinner 
ice cover at the end of the annual melting cycle. The critical factor to 
assess these changes is the sea ice thickness distribution. However, 
satellite-based ice thickness monitoring does not yield reliable results 
in the summer season, due to unfavourable surface conditions such as melt 
ponds. Therefore, we estimated the regional sea ice thickness 
distribution along the cruise track with helicopter surveys with an 
airborne electromagnetic induction sensor (EM-Bird). The assessment of 
the ice thickness distribution was accompanied by hourly visual 
observations of sea ice conditions from the bridge. While the airborne 
ice thickness surveys revealed a snapshot of the Arctic sea ice thickness 
distribution, an Ice Mass Balance (IMB) buoys was deployed to monitor the 
ice thickness evolution at a selected location throughout the Arctic 
winter. Besides the IMB, a total of 11 ice drifting buoys were deployed 
in coordination with the International Arctic Buoy Program (IABP) along 
the cruise track, which measure ice drift and meteorological parameters. 

The observed thinning demonstrates a shift of sea ice regimes in the 
central Arctic, which has consequences for the physical and biological 
properties of sea ice and the upper ocean layer. To assess and quantify 
these changes towards a younger and thinner sea ice cover we measured the 
physical properties of sea ice, such as ice texture and spatial and 
spectral distribution of light transmission through sea ice. The optical 
measurements were carried out with a Remotely Operated Vehicle (ROV) 
during ice stations and from the deck of Polarstern. The work on the ice 
stations was completed by ice coring at selected sites and high- 
resolution ground EM ice thickness measurements. 

This report presents the work of the sea ice physics group in individual 
chapters for sea ice thickness data acquisition, ROV optical 
measurements, ice station work, buoy deployment and visual sea ice 
observations. An overview of these activities is given in Figure 3.1. 

Fig. 3.1: Overview of activities of the sea ice physics group during ARK-
XXVII/3. Sea ice thickness data was acquired during helicopter surveys 
(blue triangles) along the cruise track. Optical measurements of spectral 
light transmissivity through sea ice and upper ocean layer were carried 
out during several ice stations and from the working deck of Polarstern. 
Several drifting buoys were deployed. Not shown here: Hourly visual sea 
ice observations from the bridge. 


3.1  Airborne sea ice thickness surveys 

     Stefan Hendricks,                      Alfred-Wegener-Institut
     Priska Hunkeler,  
     Robert Ricker 

Objectives 

Airborne electromagnetic (AEM) inductions soundings of sea ice thickness 
during ARK-XXVI/3 extend the existing time series of ice thickness 
surveys in the Transpolar Drift during the Arctic summer. This 
geophysical method is based on the contrast of electrical conductivity 
between sea ice and ocean water layers and presents the only method of 
direct airborne sea ice thickness measurements. The surveys are typically 
carried out by sensors, so called EM-Birds, which are towed by a 
helicopter or fixed-wing aircraft above the ice surface. As an 
alternative, ground-based induction sensors can be used for high 
resolution but lower coverage EM ice thickness estimates on ice stations. 
The time series of AEM ice thickness measurements in central Arctic 
extends back to 1991 in irregular intervals. This dataset is of 
particular importance since sea ice thickness products from spaceborne 
platforms are not available during the summer season, when the ice 
surface is covered by melt ponds. Therefore, we used AEM to estimate the 
sea ice thickness distribution in the central Arctic Transpolar Drift in 
summer in order to help understand the sea ice mass balance in the 
complete annual cycle. 


Fig. 3.2: (a) EM-Bird on the helicopter deck of Polarstern. (b) The 
          sensor is towed by a helicopter in an altitude of around 12 m 
          over the ice surface. 




Work at sea 

In total, 16 helicopter flights with more than 2500 km of sea ice 
thickness profiles were conducted during ARK-XXVI/3. Each flight track 
followed a triangular pattern with a side length of 40 nautical miles 
(74.2 km). The EM-Bird is typically operated in an altitude of 40 feet 
(12 m) above the sea ice surface (Fig. 3.2). Every 15 to 20 minutes, the 
helicopter ascends to an altitude of 500 feet for system calibration and 
radio contact with the bridge of Polarstern. Two operators were involved 
in the surveys for control of the EM-Bird and additional sea ice 
observations with geolocated aerial photography. The oblique aerial 
images were taken approximately every one or two minutes from front seat 
of the helicopter facing in flight direction with a GPS-capable digital 
camera (Ricoh Caplio 500SE). 


Fig. 3.3: Overview of the location and dates of all airborne EM sea ice 
          thickness surveys during ARK-XXVI/3. The survey flights are 
          given by triangular shaped and roughly 200 km long profiles. 


Throughout the cruise, helicopter operations were significantly hampered 
by unfavourable weather conditions such as low visibility caused by fog 
or low clouds. Therefore, data from only two flights exist on the 60W 
transect to the north pole. The weather situation improved after August 
24, resulting in daily helicopter surveys. After August 30 flight 
conditions worsened again, allowing only 6 additional flights until 
Polarstern left the sea ice covered region. 

The list of all available flight is given in Figure 3.3 and Table 3.1. 
Several flights had to be aborted early because of weather conditions, 
leaving a mean track length of 156 km per survey. During the end of the 
cruise some surveys were shifted to night (ship time), when weather and 
light condition were more favourable. 

The processing of the EM data requires the knowledge of the electrical 
conductivity of the sea water. This information was obtained by the ships 
thermosalinograph. The conductivity values were determined for each 
flight in steps of 100 ms/m (Tab. 3.1). In addition, the sea ice 
thickness data of each flight was calibrated on sites of open water, 
which were marked by the EM operator during the surveys. 


Tab. 3.1: List of all airborne EM sea ice thickness surveys during ARK-
          XXVI/3 with thickness statistics 

   Date     Flight  Conduc-  Length  Modal   Mean   Standard  Median  
                    tivity           Thick-  Thick-   Devi-   Thick-
                                     ness    ness     ation   ness  
                    [mS/m]    [km]    [m]    [m]       [m]     [m]  
——————————  ——————  ———————  ——————  ——————  ——————  ———————  ——————
2011/08/15    #1     2600     77,6    0,8    1,24     0,60     1,09  
2011/08/16    #1     2600     156,7   0,9    1,29     0,60     1,14  
2011/08/22    #1     2600     155,4   0,8    1,21     0,66     1,03  
2011/08/24    #1     2500     186,0   1,1    1,56     0,87     1,33  
2011/08/24    #2     2500     191,5   1,1    1,61     0,97     1,34  
2011/08/25    #1     2500     214,5   0,9    1,34     0,80     1,13  
2011/08/26    #1     2500     204,7   0,9    1,58     0,90     1,35  
2011/08/27    #1     2500     217,2   0,9    1,60     1,27     1,23  
2011/08/28    #1     2500     182,2   0,9    1,43     0,79     1,20  
2011/08/30    #1     2500     29,3    1,1    1,61     0,86     1,37  
2011/09/02    #1     2400     149,9   0,9    1,26     0,68     1,08  
2011/09/05    #1     2300     203,3   0,7    1,14     0,96     0,92  
2011/09/07    #1     2400     195,2   0,6    1,02     0,57     0,84  
2011/09/12    #1     2400     63,3    0,6    0,99     0,60     0,85  
2011/09/14    #1     2400     169,0   0,1    0,34     0,36     0,22  
2011/09/17    #1     2500     191,2   0,0    0,78     0,87     0,54  


Preliminary results 

Exemplary sea ice thickness results of typical first-year and multiyear 
sea ice floes can be seen in Figure 3.4. Typical first year level sea ice 
shows a thickness of less than 1 m and very few ridges with thicknesses 
larger than 4 m. It has to be mentioned however, that the airborne EM 
underestimates maximum thickness of pressure ridges by as much as 50%, 
due to footprint effects. While the amount of thick ice (> 6 m) is 
generally low for first-year ice, multiyear sea ice can easily exceed 
thicknesses of 8 m or more at a length of 1 km, as can be seen in the 
lower part of Figure 3.4. 

In general, typical first-year sea ice thickness distributions dominate 
the dataset, with only very few multiyear floes. Consequently, the modal 
thicknesses of the individual flight range between 0.6 m and 1.1 m in the 
central ice zone and 0.0 to 0.1 m close to the ice edge (Tab. 3.1). The 
highest modal and mean thicknesses were found between August 24 and 
August 30 in the area close to the North Pole, which coincides with the 
highest density of multiyear ice floes. The rare amount of multiyear sea 
ice is confirmed by the visual observations of the ice surface during the 
surveys (Example: Fig. 3.5). Multiyear and first-year sea ice surfaces 
show distinct characteristics with respect to surface features and melt 
pond concentration, however quantitative results are difficult to obtain 
from the oblique aerial imagery. 

The average sea ice thickness distribution from all data points is shown 
in Figure 3.6. The modal thickness of 0.9 m matches the result from 2007 
(Polarstern cruise leg ARK-XXII/2) in the region of the Transpolar Drift 
Stream. However, not only the modal thickness, but also the entire shape 
of the ice thickness distributions from summer 2007 and 2011 are very 
similar. Regional differences do exist in the different surveys, but the 
comparison reveals, that the general ice conditions were very comparable 
in the two years of 2007 and 2011. 

Fig. 3.4: Sea ice thickness examples from the EM-Bird system. The top 
          panel (a) shows typical summer first year ice as found during 
          ARK-XXVI/3 and the lower panel (b) shows thicker multi-year sea 
          ice, which was occasionally found during the surveys. 

Fig. 3.5: Exemplary sea ice observation photo. The photos were acquired 
          by sea ice observers in the front passenger seat of the 
          helicopter and are automatically written with a UTC timestamp 
          and GPS position. 

Fig. 3.6: a) Locations of all EM-Bird sea ice thickness surveys of 2007 
             (ARK-XXII/2, red) and 2011 (ARK-XXVI/3, blue). 
          b) Sea ice thickness distributions of all EM data points in 
             2007 and 2011. Marked are the modal thicknesses (maximum of 
             the ice thickness distribution) for the respective years. 


3.2  Optical measurements 

Marcel Nicolaus, Christian Katlein          Alfred-Wegener-Institut 

Objectives 

The amount of solar light transmitted through snow and sea ice plays a 
major role for the energy budget of ice-covered seas. Thus, it is of 
critical importance for formation and melt of sea ice. In addition, the 
horizontal and vertical distribution of light under sea ice impacts 
biological processes and biogeochemical fluxes in the sea ice and the 
uppermost ocean. Due to their different absorption spectra, snow, sea 
ice, sea water, biota, sediments, and impurities affect the spectral 
composition of the light in its way from the atmosphere into the ocean. 
During the last years, the number of studies of spectral light 
measurements under sea ice has increased. However, observations that 
allow insight into the spatial variability of under-ice irradiance and 
radiance are still sparse, and little is known about how light conditions 
change on different scales from meters to kilometres. In addition, there 
are only very few data on the total energy budget under sea ice as well 
as on relating biomass estimates to radiation measurements. Therefore, we 
have performed comprehensive measurements of spectral radiation over and 
under sea ice during ARK-XXVI/3. 

Work at sea 

We have measured spectral irradiance and radiance of visible light 
(wavelength range from 350 to 920 nm with 3.3 nm resolution) above and 
beneath sea ice with Ramses spectral radiometers (Trios GmbH, Rastede, 
Germany), using different setups in order to gain different kind of data 
sets related to different objectives. Radiance measurements (7 field of 
view) are best suited for studying the spatial variability of optical 
properties of sea ice, because the measured signal originates from a 
comparably small area. Irradiance measurements (cosine receptor) are best 
suited for studying the energy budget at the point of measurement, 
integrating all incident energy (from above) at this point. Optical 
measurements have been performed during each ice station (Fig. 3.7, 3.8 
and Tab. 3.2). 

ROV measurements 

We operated two radiometers synchronously on a Remotely Operated Vehicle 
(ROV, Ocean Modules V8ii, Åtvidaberg, Sweden) under the sea ice with one 
reference senor at the ice surface. From these measurements, we obtained 
horizontal transects and vertical profiles of under-ice irradiance (Edw) 
and radiance (Idw). In total, the ROV was operated successfully during 
two tests from the working deck of Polarstern and directly from the sea 
ice during nine ice stations (Fig. 3.7. 3.8, and Tab. 3.2). In addition, 
two ROV operations were not successful due to problems with the power 
supply (August 14) and with the magnetic compass (August 26). The data 
quality from measurements on September 11 strongly suffered from very low 
solar irradiance (local time night hours). All other data sets look most 
promising. 

Fig. 3.7: Overview of all ROV stations. The background image gives sea-
          ice concentration on August 8, 2011 for the first part and 
          September 15, 2011 for the second part of the cruise. Numbers 
          in brackets give Polarstern station numbers. The Magnetic Pole 
          was almost reached with the ice station on August 31 (78-230). 

Fig. 3.8a: Sketches and Overview images of ROV sea-ice stations with 
           profile lines (dark blue), selected markers with according 
           numbers (red dots), depth profiles (green arrows), biooptical 
           cores (light green cylinders), and the depths of main dives. 
           The yellow ellipse indicates the ROV launch hole and the red 
           triangle the location of the pilot tent. 

Fig. 3.8b: Sketches and Overview images of ROV sea-ice stations with 
           profile lines (dark blue), selected markers with according 
           numbers (red dots), depth profiles (green arrows), biooptical 
           cores (light green cylinders), and the depths of main dives. 
           The yellow ellipse indicates the ROV launch hole and the red 
           triangle the location of the pilot tent. 


Tab. 3.2: All ROV profiles where data were recorded. Dates (UTC) refer to 
          the ROV measurements (not station beginning). Markers are named 
          with "M "and their number, e.g. M6 for marker number 6. 
          Abbreviations: MYI: multi year sea ice, FYI: first year sea 
          ice. 

Date PS   Profile (@ ROV depth   length/    Sea ice and       Surface      Comments  
station                          Depth      thickness         conditions 
                                 (m)                          Pond status  
————————  ————————————————————   —————————  ————————————————  ———————————  ————————————————————————
12.08.11  Profile @ 2.0m         ca. 110    Mostly FYI        No snow,     ROV test from Polarstern 
78-198    Profile @ 5.0m         ca. 110    Mostly FYI        open ponds   Irradiance only  

16.08.11  Depth under ice        20                           No snow,     ROV test from Polarstern 
78-207                                                        open ponds   Profile at floe edge  

17.08.11  Profile @ 2.5m         100        FYI 1.1m          No snow,  
78-209    Profile @ 5.0m         50         FYI 1.1m          open ponds
          Profile @ ice bottom   30         FYI 1.1m                       "Stop and go" mode
          Profile @ ice bottom   no data    FYI 1.1m                       Continuous, bad
          Depth @ M30            50         FYI 1.1m                       positioning  
          Depth                  13         Open water          

19.08.11  Profile 000° @1.5m     120        FYI 1.2m          No snow,   
78-212    Profile 045°, @1.5m    60         FYI 1.2m          open ponds
          Profile 095°, @1.5m    120        FYI 1.2m          
          Profile 175°, @1.5m    120        FYI 1.2m          
          Profile 220°, @1.5m    150        FYI 1.2m          
          Profile ridges, @15m   points     MYI < 8.0m        
          Grid @1.5m             30x15      FYI 1.2m          
          Depth @ M30            50         FYI 1.2m            

22.08.11  Grid @ variable depth  30x50      MYI 1.5-3.5m      Frozen sur-  Only radiance sensor  
78-218                                                        face and
                                                              ponds,
          Depth @ M16            10         MYI 1.5-3.5m      no snow  

31.08.11  Profile @ variable                FYI 1.1m          2-3 cm       ROV in Deck mode,  
78-230    depth                                               new snow,    no pressure sensor,
                                                              ponds fro-   bad data quality
                                                              zen (7cm)  

03.09.11  Profile 1 @ 4-8m       2x130      MYI 2.0-3.8m      2-3 cm  
78-235    Profile 1 @ 8m         2x130      MYI 2.0-3.8m      new snow, 
          Profile 1 @ variable                                
            depth                120        MYI 2.0-3.8m      ponds fro-
          Profile 2 @ 2m         2x80       FYI 1.2m          zen (10cm)
          Depth @ M4             90         MYI close FYI 
          Depth @ M8             100        FYI close water   
          Surface depth profile  5          MYI/FYI  
  
06.09.11  Profile @ 1.2m         30         FYI 0.8m          Snow 3 cm,  
78-238    Profile @ 2.0m         120        FYI 0.8 (to 2.0)  ponds fro-
          Profile @ 4.0m         120        FYI 0.8 (to 2.0)  zen
          Profile @ 6.0m         105        FYI 0.8 (to 2.0)  
          Profile @ variable                                  
            depth                120        FYI 0.8 (to 2.0)  
          Cross profile @ 3.0m   70         FYI 0.8                        Bad positioning
          Depth @ M2             50         FYI 0.8 (to 2.0)  
          Depth                  5          FYI 0.8 (to 2.0)    

09.09.11  Profile @ 1.0m         120        FYI 1.2m          Snow  
78-245    Profile @ 1.2m         90         New ice 0.3m      10cm,        New ice = frozen lead
          Profile @ 2.0m         2x210      FYI + new ice     ponds        
          Profile @ 4.0m         210        FYI + new ice     frozen       
          Profile @ 1.0m no snow 15         New ice 0.3m                   Snow removed M1-M2  
          Profile @ 2.0m no snow 15         New ice 0.3m                   Snow removed M8-M9 
          Profile @ 2.0m no snow 15         FYI 1.2m                       Snow removed M8-M9 
          Depth @ M2             40         New ice 0.3m 
          Depth @ M11            25         FYI 1.2m

11.09.11  Profile @ 2.0m         Ca.        New ice + MYI     Ponds fro-   Low light level, bad data  
78-250    Depth                  4x30       Open water        zen, snow    quality (night station),
          Depth                  10         Open water        covered      Bad positioning
                                 3             

16.09.11  Profile @ 4.0m         Total 450  MYI 1.7 to 2.9m   Ponds fro- 
78-267    Profile @ variable                                  zen, snow 
            depth                Total 240  MYI 1.7 to 2.9m   covered
          Depth @ M4             50         MYI 1.7 to 2.9m 
          Depth                  25         Open water  


The ROV system consisted of a surface unit (incl. power supply, control 
unit, monitor), a 300-m long tether cable, and the ROV itself. The ROV is 
controlled and moved by eight thrusters allowing diving speed of up to 
1.0 m/s. The standard measurement speed (using 25% thruster gain) was 
about 0.25 m/s for horizontal and vertical profiles. The speed varied 
from profile to profile and depended on under-ice currents as well. The 
ROV was equipped with two standard VGA video cameras, one looking forward 
and one looking backward (Fig. 3.9). Both cameras were used for 
navigation (orientation) and to document the dives. One video signal, 
usually the forward one, was recorded always. An altimeter (DST Micron 
Echosounder, Tritech, Aberdeen, UK) and a sonar (Micron DST MK2, Tritech, 
Aberdeen, UK) were mounted to support navigation and measure the 
distances to obstacles and markers (see below). The altimeter was 
particularly used to measure the distance between the radiometers (ROV) 
and the sea ice. In addition, the ROV measured its depth, heading, roll, 
pitch, and turns and displayed this as an overlay together with a time 
stamp on the control monitor (Fig. 3.10). After it was found that the 
designated 5-kW generator was not able to power the ROV system under full 
load (August 14), ship's power was used on all stations. For this, 100 to 
150 m of cable had to be laid out from the vessel to the ROV site (tent). 
This also restricted the choice of the launch site to a distance smaller 
than the cable length. The ROV was balanced in a pool on the working deck 
of Polarstern with actual sea water. Doing so, it was balanced slightly 
heavy in order to make it sink down, finally hanging straight under the 
launch hole, in case of any failure. Similarly, the tether was slightly 
negatively buoyant, too. Salinity variations between the stations due to 
sea ice melt leaded to slightly varying balancing throughout the cruise. 

The irradiance sensor (type SAMIP) was directly implemented into the ROV, 
meaning its communication was led through the tether, using (the last) 
unused twisted pair. The radiance sensor (type SAM) was connected through 
a separate 150-m long cable, which was strapped to the tether and dragged 
along. This limited the operation radius to 150 m when both sensors were 
used (standard setup). At the surface, both sensors were connected to one 
interface box (type PS 100 or IPS 400) each. All data were directly 
recorded into a PC running the sensors' software MSDA_xe. An additional 
reference irradiance sensor (type SAMIP) was mounted on a tripod on the 
sea-ice surface measuring incident solar radiation (Ed). All sensors were 
triggered synchronously in intervals of 2 to 10 s, depending on light 
conditions under the ice. Integration times of the sensors varied 
depending on ice conditions between 512 and 4048 ms, with longer times 
for the irradiance sensor due to the lower light transmittance of the 
opaque cosine receptor. The overall point-to-point distance was approx. 
1.0 m for irradiance and 2.0 m for irradiance measurements. 


Fig. 3.9: Photograph of the Ocean Modules V8ii ROV equipped with two 
          Ramses radiometers, one measuring irradiance (left) and one 
          measuring radiance (right). An additional rear-looking camera 
          is not visible in this photograph. 

Fig. 3.10: Under-sea-ice photograph extracted from the ROV (front) camera 
           video record (Station August 19, 78-212). It shows the smooth 
           ice bottom and a marker stake (1-m long, 0.1-m sections). 
           Differences in brightness indicate differences in light 
           transmission. In addition, navigational information is 
           overlaid. Abbreviations [and units]: pitch and roll [deg], 
           Dpt: depth [m], Hdn: heading [deg], Trn: turns, Date [yymmdd], 
           Clk: clock/time [UTC]. 

Fig. 3.11: Photograph of the ROV site taken from board Polarstern during 
           the ice station on September 2 (78-235). The main picture 
           shows the deployment hole in a frozen (surface) melt pond, the 
           yellow tether, and the pilot tent. The inset picture shows two 
           ROV pilots, one controlling the ROV and one controlling the 
           sensors and documenting all operations. 


All electronics were set up in a pilot tent (Fig. 3.11), which was heated 
when necessary. The ROV operations always needed four persons: one pilot 
controlling the ROV, one co-pilot controlling the optical sensors and 
documenting the dive, one tether handler, and one polar-bear guard. The 
ROV was launched through melt ponds (preferably melted all the way 
through) or over floe edges in order to reduce the amount of work for an 
access hole to a minimum. We found that this worked out nicely under the 
given summer conditions. After an initial system check and test dive, the 
profiles (grids) were marked with numbered, red-white colored poles, 
hanging under the ice through drill holes. Sea-ice thickness, snow 
thickness / surface layer thickness / pond depth, and freeboard were 
measured at each hole. Additional measurements of total sea-ice thickness 
were performed by EM31-measurements (see other section) over the profiles 
(not all stations). Furthermore, surface features, such as pond 
distributions along the profiles, were noted to support later analyses. 
Over all, such an ROV station (setup, measurements, packing) took six to 
eight hours. 

The preferred mode of operation for the ROV is "Normal horizon" mode. In 
this mode, the ROV keeps its own position in the water stable whenever no 
other command is given. This mode was used on the first two ROV ice-
stations (until August 22) without any problems. Closer to the magnetic 
pole (137.3W, 85.25N) this mode did not work anymore, because it requires 
a stable compass information, which was not given since the field 
strengths of the horizontal component of the magnetic field was too low 
(<2000 nT). On August 31 the ROV was operated in "Deck mode" meaning no 
stabilization at all. Additionally, the depth sensor did not work and ROV 
depth had to be read from the SAMIP module of the irradiance sensor. With 
this, we managed to fly one 50-m long profile, but the quality of optical 
data is much lower than on all other stations. From September 3 onwards, 
the ROV was operated in "Normal horizon" again, but it was not possible 
to use the compass (heading information) for orientation any longer. The 
compass signal was strong enough to prevent the ROV from crazily 
spinning, but still highly variable and drifting. 

Standard profiles were dives of constant depth, mostly on 2, 4, or 6 m 
depth. Additional tests were also performed with flights following 
topography or simulating point measurements by diving up to the ice 
bottom for each measurement. But these routines were found to be more 
difficult to handle and analyse later on. Depending on flight depth and 
marker depth, it was found to be difficult to position the ROV precisely 
under the ice. In general, orientation and positioning were quite 
difficult and caused most problems for the ROV operation. Depth profiles 
were found to be best when following a long line hanging under the ice in 
order not to lose orientation and drift too far off the profile due to 
currents. 

Stationary setup 

Time series of solar irradiance (no radiance measurements) over and under 
sea ice (e.g. albedo and transmittance) were measured with a stationary 
setup of a radiation station (Fig. 3.12). This radiation station was set 
up in different configurations of three to five radiometers during four 
ice stations for up to 12 hours (Fig. 3.7 and Tab. 3.2). The station at 
the North Pole on August 22 did not record any data due to an operational 
mistake. An additional radiation station was deployed on the Peildeck of 
Polarstern from September 21 to 23. This station consisted of three 
irradiance sensors and one radiance sensor, all measuring incident solar 
radiation in order to inter-compare the sensors and to enable comparisons 
with the standard short-wave measurements of the meteorological station 
on board Polarstern. 


Fig. 3.12: Photograph of the radiation station. Two sensors are mounted 
           above the surface for albedo measurements (left rack), one 
           mounted on an l-arm held by the yellow stand, and two hanging 
           under the ice at the position of the l-arm. Station on 
           September 5 (78-238). 


Each station on the sea ice consisted of two sensors at the surface 
(downward and upward, Ed and Eu) mounted on a horizontal bar between two 
tripods and one upward looking sensor mounted on an L-Arm (see below) 
adjusted directly at the sea-ice bottom (Edi). On September 5 and 8, two 
additional under-ice sensors were added hanging in the water in a depth 
of 6.0 m. One sensor was installed in a small frame looking upward (Edw) 
and one was hanging on its cable looking downward (Euw). These sensors 
were added to get a more comprehensive idea of the energy budget under 
the ice, including upward irradiance. 

All data were recorded in a customized version of a Tribox2 (Trios GmbH, 
Rastede, Germany) with an additional interface box to enable synchronous 
recording of up to five sensors. Logging interval was 1 min. The station 
was powered using two 75 Ah car batteries. All electronics was placed in 
a white isolated box (Fig. 3.12). 

Point measurements (L-Arm) 

Point measurements of spectral radiance and irradiance directly at the 
bottom of the sea ice (Edi and Idi) were performed using a foldable 
holder, so called L-Arm (Fig. 3.13), through core holes of 10 cm 
diameter. This arm was pushed straight through the hole before the 
bottommost section was folded up by pulling a rope. This resulted in the 
sensor being upright right at the ice-water interface, 80 cm away from 
the centre of the core hole. An additional irradiance sensor was set up 
close to the measurement to measure Ed. L-arm measurements were mostly 
performed using an irradiance sensor. Only on August 29, comparison 
measurements were made, using a radiance sensor on the L-Arm and 
measuring at the same positions. Mostly, the core from the access hole 
was used as texture core (TEX) for this site. 

L-arm measurements were performed at all four stationary setups and 
during three additional stations independently of station measurements 
(Fig. 3.7 and Tab. 3.3). On August 19, these measurements were also 
performed directly in a melt pond. For stationary measurements, the L-Arm 
was mounted in a tripod, for other stations, the L-Arm was operated and 
held by a person. Such it was also possible to perform multiple 
measurements from one access (core) hole by rotating the L-Arm, e.g. in 
45 steps. 


Fig. 3.13: Photograph of under-ice radiation measurements using a 
           foldable holder, so called l-arm. Station on August 29 
           (78-227). 


Tab. 3.3: All optical stations and l-arm measurements, where data were 
          recorded. Dates (UTC) refer to the optical measurements (not 
          station beginning). Abbreviations for irradiance sensors: Ed / 
          Eu: Downward / upward (reflected) at surface; Edi: Downward at 
          sea-ice bottom; Edw / Euw: Downward / upward in water under sea 
          ice at 6 m. Abbreviations for radiance sensor: Id: Downward at 
          sea-ice surface, Idi: Downward at sea-ice bottom 

Date        l -arm            Station       Ice / snow                    Comments
PS station                    (Sensors)  
——————————  ————————————————  ————————————  ————————————————————————————  —————————————————
11.08.11    Site 1: 5 angles                MYI 1.5m, no snow  
 78-195

14.08.11                      Ed, Eu, Edi   Ed + Eu on MYI, no snow       6.5 h data  
 78-203                                     Edi under FYI 1.2m, no snow

19.08.11    Site 1: 5 angles                FYI 1.0m, no snow    
 78-212     Site 2: 5 angles                FYI 1.0m, no snow
            Site 3: 5 angles                Pond

29.08.11    Site 1: 5 angles                FYI 1.4m, surface layer 3 cm  MYI 3.3m     
 78-227     Site 2: no data
            Site 3: 6 angles                FYI 1.4m, surface layer 3 cm  At pond edge 
            Site 4: 6 meas.                 YI 3.3m                       Transect to
                                                                          pond edge

06.09.11                      Ed, Eu, Edi,  MYI 2.1m, snow covered        19 h data  
 78-238                       Edw, Euw

09.09.11                      Ed, Eu, Edi,  FYI 1.2m, snow covered        9.5 h data  
 78-245                       Edw, Euw

21.09.11                      4x Ed (Id)    Peildeck                      Sensor comparison  
   to 
23.09.11


L-arm measurements were recorded either directly into a standard PC (see 
also ROV measurements) or using a handheld PC (TBS Nomad, Trimble / 
Tripod Data Systems, Corvallis, USA), connected via Bluetooth to the IPS 
box, and running Pocket MSDA software (Trios GmbH, Rastede, Germany). 
Under-ice and above-ice measurements were triggered manually and 
synchronously. 

Bio-optical ice cores 

During the cruise, 14 bio-optical cores (named ҏPTө were obtained from 
the sea ice. These cores were obtained to study correlations between bio-
optical sea-ice parameters (pigment content, particular absorption, 
dissolved organic matter) and the light measurements (spectral optical 
properties). All cores were drilled at points where under-ice irradiance 
was measured before. The cores were segmented into (mostly) three pieces: 
topmost 20 cm, bottommost 20 cm, and the remaining middle part. For 
further treatment and analyses see Sea Ice Biology section of this 
report. 

Preliminary results 

During the cruise, all radiation measurements (spectra) were processed 
from measured raw data to calibrated 
fluxes. However, results from 
sensor inter-comparisons and additional calibration and plausibility 
tests were not applied yet. In addition, most work was done to geo-
reference all measurements, in particular to localize the under-ice ROV 
data. Station and L-Arm data were not processed any further and no 
preliminary results can be given in this report. 

Exemplary ROV result (Station on August 22, North Pole Grid) 

ROV measurements of under-ice radiance were performed along a 30x50-m 
grid on MYI on August 22. The grid was marked in a 10x10-m grid with 
markers in advance (red circles in Fig. 3.14), except pond locations in 
order not to destroy the thin new ice crust on top of the freshly frozen 
pond surfaces. Due to navigational problems, the resulting data grid is 
not entirely matching the designated grid. However, all points were 
reached. Measurements with uncertainties in localization are not shown 


Fig. 3.14: Overlay of an aerial photograph and preliminary results of 
           under-ice transmittance (derived from the radiance sensor) at 
           the North-Pole station on August 22 (78-218). The scale is in 
           fraction, e.g. 0.2 means 20% of solar irradiance reach the 
           bottom of the ice.  


and used for analyses. The aerial photograph was taken during a 
designated helicopter flight and distorted to match the marker positions 
(GPS referenced). Figure 3.14 shows the fraction of incident light 
reaching the bottom of the sea ice. This result is based on radiance 
measurements, showing distinct differences of white ice (lower 
transmittance of about 2-3%) and ponded ice (higher transmittance of 10 
to 20%). In addition, the result points to a strong variability of light 
transmission also within one category (white or ponded ice). 


General summary of ROV measurements 

Spectral radiometers were operated for the first time under Arctic sea 
ice on an ROV, which was launched through the ice during ice stations. A 
comprehensive dataset was gathered from 42 dives on 11 stations. The core 
data set consists of 11 depth profiles (> 10 m) and 51 horizontal 
transects (4.4 km of data). In total, 3100 irradiance and 6700 radiance 
spectra (after quality control and localization) were recorded, resulting 
in a data set with a spatial resolution better than 1 m in horizontal 
transects and depth profiles under various sea-ice conditions. Most 
optical measurements were co-located with physical, biological, and 
biogeochemical sampling of sea ice and water. 

Our results show a broad range of light conditions that can be related to 
ice and water conditions as functions of sea-ice and snow thickness, 
melt-pond coverage, and biomass. Although these data are not analysed in 
any detail, the data set shows that light regimes differ strongly between 
multi- (MYI) and first-year sea ice (FYI), as well as between ponded and 
white ice of each ice type. In addition, comparing Atlantic and Pacific 
water masses also shows strong differences with much more light 
penetrating much deeper in Pacific than in Atlantic waters. 



3.3  Ice station work and ice cores 

     Mario Hoppmann, Robert Ricker          Alfred-Wegener-Institut 


Objectives 

The goal of the ice station work was to characterize the physical state 
of the sea ice such as ice temperature and salinity, texture and high- 
resolution ice thickness distribution. This data complements the large-
scale aerial thickness surveys in terms of ice type classification with 
additional parameters than thickness. The analysis of sea ice cores at 
each station reveals the ice age and the stage of melting and can be used 
to describe the history of the sampled ice station. High resolution ice 
thickness data reveals the local ice thickness distribution and shows the 
representativeness of the ice cores on the ice station. The main 
objective is therefore to assess the state of different types of sea ice 
along the cruise track and compare the results with those of earlier 
cruises and to answer the scientific question of how the basic physical 
parameters of sea ice have changed in the Arctic Ocean becoming dominated 
by first-year ice. 

Work at sea 

The work at sea can be divided into 12 ice stations where several cores 
were retrieved. Table 3.4 and Figure 3.15 give an overview about the 
several ice stations and ice cores. On each ice station salinity (SAL) 
and temperature (ARC) cores were drilled. In addition to that texture 
cores (TEX) and North Pole cores (POL) were taken at some stations. We 
choose for each ice station a coring site that covered an area of about 4 
m2. The salinity and temperature cores were always retrieved in direct 
vicinity. Afterwards a half pipe was used for cutting and analysing. 


Tab. 3.4: List of all sea ice cores with their length and assigned names 

                   Date        Core Name   length [cm]  
                   ——————————  ——————————  ———————————
                   11.08.2011  110811-ARC      164  
                               110811-TEX1     196  
                   14.08.2011  110814-ARC      200  
                               110814-TEX      
                               110814-SAL      190  
                   17.08.2011  110817-ARC      140  
                               110817-SAL      170  
                   19.08.2011  110819-ARC      135  
                               110819-SAL      140  
                               110819-TEX1b  
                               110819-TEX2      
                   22.08.2011  110822-SAL      243  
                   23.08.2011  110823-ARC      280  
                               110823-POL1      
                               110823-POL2      
                               110823-POL3      
                   26.08.2011  110826-ARC      164  
                               110826-SAL      170  
                               110826-MAJO      
                   29.08.2011  110829-ARC      151  
                               110829-SAL      153  
                               110829-TEX1      
                               110829-TEX2      
                   31.08.2011  110831-ARC      198  
                               110831-SAL      153  
                   03.09.2011  110903-ARC      215  
                               110903-SAL      240  
                   06.09.2011  110906-ARC      181  
                               110906-SAL      179  
                               110906-TEX1      
                   09.09.2011  110909-ARC      116  
                               110909-SAL      116  
                               110909-TEX1      
                   11.09.2011  110911-ARC      156  
                               110911-SAL      158  


Fig. 3.15: Overview of ice station locations, dates and the corresponding 
           Polarstern station numbers. 


In addition, the thickness distribution of each station was mapped by a 
survey with a hand-held EM ice thickness (EM31 MkII, Geonics Ltd.). The 
surveys were motivated by general ice type classification but also to 
provide near real-time ice thickness maps, which were used to identify 
suitable locations for buoy deployments. 


3.3.1 Temperature and salinity 

Salinity and temperature of sea ice are two important parameters for 
describing its properties. The salinity profile of young and first year 
ice usually shows a characteristic C-shape due to brine movement (Fig. 
3.16). The difference in salinity between brine that leaves the sea ice 
and brine that enters the ice is responsible for the net desalination of 
sea ice and thus leads to the characteristic bulk salinity profiles in 
Fig. 3.17. However, environmental conditions exist, which can lead to 
variability in the salinity. The curve of the August profile shows a very 
low surface salinity. This can be explained with the surface warming 
during summer and the resulting snow melt that flush salt downwards 
through the ice cover. 


Fig. 3.16: Sea-ice salinity profiles from August to October (after 
           Petrich & Eicken, 2010). 

Fig. 3.17: Example of temperature and salinity profiles of two ice 
           stations. Note that the zero in Depth refers to the local 
           freeboard. The difference in length between the 110909ARC 
           and 110903SAL shows that there has to be a kind of rough-
           ness at the bottom side of the sea ice because the drill 
           holes were not more than 1 m away from each other 


The temperature was measured while in 10 cm steps small holes were 
drilled into one core to place the rod thermometer (Fig. 3.18). The 
measurements were made directly after drilling to avoid a change in 
temperature of the ice. The core was immediately packed into one or 
several labeled plastic bags and was carried into the ice laboratory to 
store it at a temperature of -20°C. 

The salinity core was sawed in slices of 10 cm and packed into boxes. 
After melting of the samples, the salinity was measured onboard with a 
salinometer of type "WTW Cond 3151" Afterwards small samples were filled 
up for biological studies. 

Sea ice thickness and draft at the coring sites was measured with a 
thickness gauge. Furthermore, snow or rotten ice at the surface that 
layer was measured with a ruler stick when present. The slush at the top 
of the core segments was always thrown away. Sometimes the core length 
did not fit to the measured thickness that was mainly caused by voids in 
the ice sample. 

Preliminary results 

We took the cores during August and September within the melting period 
of the sea ice, although in September it already started to freeze at the 
surface. The measurements show a low salinity throughout the cores (Fig. 
3.17). 

In addition to that the drilled cores exhibit a high porosity. This led 
to the effect that during sawing the core into slices and also shortly 
after drilling an unknown amount of brine got lost. That is why some 
salinity profiles have an irregular shape near zero. 

10823ARC and 110903ARC have a similar temperature profile (Fig. 3.17). 
The top of the profile is ruled by an almost linear increase from the air 
temperature to the warmest segment of the core, which is always near the 
freeboard. This is followed by an almost linear decrease down to circa -
1.0°C, which corresponds to the temperature of the underlying ocean. 
110823SAL shows a typical C-shaped profile with a very low salinity at 
the surface above the freeboard, caused by flushing of surface melt 
water. Core 110903SAL shows another increase in salinity at the bottom of 
the core that might be due to rafting or multiyear ice. 

3.3.2 Ice core texture analysis 

On the scale of 100 to 10-4 m, sea ice reveals a complex internal 
structure. Crystals can assume a multitude of shapes, orientations and 
sizes, depending on the growth conditions of the sea-ice sheet.  Brine is 
included within the ice matrix both between and within crystals. The 
amount of air and brine inclusions, their orientation, as well as crystal 
morphology all affect the bulk properties of sea ice. Figure 3.19 shows 
the different textures that are commonly found in sea ice. 


Fig. 3.19: Overview of main ice textures (after Petrich & Eicken, 2010). 


The crystal structure of a core taken in the field can reveal information 
about the growth history of the ice floe and for example help to 
distinguish between first-year and multi-year ice. Before further 
processing, each sea-ice core was photographed with a scale on a black 
background (Fig. 3.20). For the texture analysis, the stored temperature 
core (ARC) was cut vertically with the help of a band saw, and a thick 
section of a few millimetres in thickness was prepared and placed on a 
light table (Fig. 3.21, Tab. 3.5). By sliding a set of crossed polarizer 
over the thick section, the texture of the core was highlighted and the 
different crystal structures and sizes, as well as the amount of bubbles 
and holes, were documented. Afterwards, the core was photographed to 
later determine the fraction of brine channels. 


Fig. 3.20: Example photo of archive core taken on August 31, 2011. 

Fig. 3.21: Equipment for texture analysis of sea-ice cores. a) Kolbe K200 
           Band Saw; b) Light table with crossed polarizers; 
           c) Microtome; d) Universal Stage. 

Fig. 3.22: Thin sections of different segments of sea-ice core 
           20110831ARC. a) 12-24cm; b) 62-74cm; c) 122-134cm; d) 166-
           174cm. 


Depending on the crystal shapes and the overall porosity of the ice core, 
vertical thin sections were prepared with the help of a microtome, but 
this was not done systematically. These were afterwards photographed 
between crossed polarizers on a universal stage (Fig. 3.22). 


Tab. 3.5: List of ice core thin sections. The sections are taken from 8 
          ice cores (see Tab. 3.4 for respective ice stations) in dif-
          ferent depth levels. 

                      Core Name    Thin sections  
                      ———————————  —————————————————
                      110819TEX1b  054-064 cm  
                                   lowermost 10 cm  
                      110823ARC    110-120 cm  
                                   132-142 cm  
                                   151-161 cm  
                                   185-195 cm  
                      110826MAJO   35 cm horizontal  
                                   139 cm horizontal  
                      110829ARC    140-150 cm  
                      110831ARC    012-024 cm  
                                   024-038 cm  
                                   062-074 cm  
                                   074-086 cm  
                                   086-098 cm  
                                   098-110 cm  
                                   110-122 cm  
                                   122-134 cm  
                                   134-146 cm  
                                   146-156 cm  
                                   156-166 cm  
                                   166-175 cm  
                                   175-185 cm  
                      110903ARC    075-087 cm  
                      110909ARC    000-010 cm  
                                   010-020 cm  
                      110911ARC    042-054 cm  
                                   072-084 cm  
                                   084-094 cm  


Tab. 3.6: Exemplary texture description of ice core 110831ARC 

from     to    type     comment  
—————  —————  ————————  —————————————————————————————————————————————————
  0,0   14,0  columnar  old columnar, small crystals, many small bubbles, 
                        crack at 12cm, big holes at 9cm  
 14,0   22,0  columnar  crystals 5-6cm, pieces missing  
 22,0   53,0  columnar  crystals 2-4cm, very big hole at 35cm, crack at 
                        38cm  
 53,0   61,0  columnar  crystals 5-10cm, few big holes at 35cm  
 61,0   63,0  granular  granular, very small crystals  
 63,0   95,0  columnar  very big crystals 5-10cm, several cm wide, big 
                        holes  
 95,0  105,0  columnar  elongated crystals 5-10cm  
105,0  120,0  columnar  old columnar, crystals 1-4cm, small bubbles, 
                        crack at 120cm  
120,0  135,0  columnar  crystals 2-4cm, not aligned, various forms  
135,0  145,0  columnar  old columnar, small crystals  
145,0  153,0  polygonal granular  crystals 2-3cm, crack at 153cm  
153,0  166,0  polygonal granular  crystals 1-2cm,  
166,0  204,0  columnar  elongated crystals diagonal 5-10cm  


Preliminary results 

Generally, thick sections from all cores show characteristic columnar 
growth, with crystal sizes varying between 1 and 15 cm. In the top 20 cm 
of most cores, the crystals outlines are blurry as signs of ongoing 
decay. In the detailed texture description (Tab. 3.6), these sections are 
called "old columnar" In addition, the first 10 cm of each core show a 
significant amount of small bubbles, originating from the strong summer 
surface melt. Throughout all cores, brine channels of different sizes are 
visible, again due to melting processes. 


3.3.3 Ground-Based EM ice thickness surveys 

High-resolution sea ice thickness data is a standard parameter for the 
characterization of an ice floe. We used a ground-based EM device (EM31 
MkII Geonics Ltd.) for mapping of the sea ice thickness distribution on 
every ice station (Tab. 3.7). This instrument is based on the same 
principles, that are used to estimate sea ice thickness from the air (See 
section: Airborne sea ice thickness surveys), however the application 
directly on the ice surface allows higher resolution thickness 
measurements than with the EM-Bird. 


Tab. 3.7: List of all EM31 ice thickness surveys with number of 
          measurement points per survey, resulting mean thickness and 
          standard deviation. 

               Date       Number       Mean         Std. Dev.
                        of Points  Thickness [m]  Thickness [m]  
            ——————————  —————————  —————————————  —————————————
            2011/08/26     2048        2.05           0.54  
            2011/08/23     4001        1.98           0.47  
            2011/09/11     7040        2.00           0.57  
            2011/08/29    10190        2.38           1.34  
            2011/09/16    14851        2.56           1.31  
            2011/09/05    18961        2.47           1.32  
            2011/08/11    19145        2.46           1.32  
            2011/08/17    21403        2.38           1.28  
            2011/09/02    25683        2.42           1.22  
            2011/08/14    30141        2.28           1.19  
            2011/08/19    31500        2.26           1.18  
            2011/09/08    36417        2.20           1.14  


During the surveys, the EM31 is placed inside a canoe (Fig. 3.23), which 
is then towed by a person over the ice surface. The canoe is free of 
metal, which might disturb the electromagnetic signal and allows ice 
thickness measurements in open melt ponds. The EM data (apparent 
subsurface conductivity) is stored in an external data logger at 1 Hz. 
The data logger is connected to a handheld GPS system, which provides UTC 
timestamp and position. Since the latitude/longitude positions are of 
limited use on the dynamic sea ice, the positions are corrected for floe 
drift and rotation by the GPS position and heading of Polarstern in post-
processing. The result is a Cartesian reference frame in meter, which is 
centered at the GPS antenna (Trimble1) of Polarstern. An example of a 
data in this reference frame is shown in Figure 3.24. The EM surveys were 
carried out in the beginning of each ice station, and graphical maps were 
created shortly after the end of the survey. Therefore, print-outs were 
available for other ice station work and were used e.g. for the 
identification of suitable buoy deployment sites. 


Fig. 3.23: Ground-based sea ice thickness survey with an EM31 Mk II 
           (Geonics Limited). The instrument was towed over the sea ice 
           in a canoe, which also allowed ice thickness measurements in 
           melt ponds (Photo: Estelle Kilias).

Fig. 3.24: Example of sea ice thickness survey (Ice station 2011/09/16). 
           Coordinates are given in a Cartesian reference frame in meter, 
           where the origin is the GPS antenna of Polarstern (Trimble1).


Preliminary results 

From analytical calculation it is known that ice thickness can be 
reliably retrieved, if the electrical conductivity of the sea water is 
known with an uncertainty of approx. 100 mS/m. For all the ice stations 
it is assumed that the conductivity of the sea ice plays no role despite 
the fact that a lot of brine channels were present during the cruise. 
Therefore, all calibration results of different ice station were used to 
construct one relation between apparent conductivity and ice thickness 
which was used for all ice stations (Fig. 3.15). The relation has the 
following form: 

                z = - 1/a • ln ( ( s - a ) / a ) - h 
                         2          a   0     1     0

The calibration procedure consists of lifting the sensor and measuring 
the response at different distances to the ice water interface 
(instrument height plus ice thickness) in a spot of level sea ice. Since 
the conductivity of the sea ice is negligible, it is practically the same 
medium as air. Thus, lifting the sensor is identical to an increase of 
ice thickness and the readings at different height can be used to 
calibrate the apparent conductivity (sa) - ice thickness (z) relation. 
From the calibration procedures we found the following calibration 
factors: a0: 1026.69, a1: -0.797, a2: 12.486. The offset h0 = 0.14 m 
describes the offset of the instrument in the canoe from the top of the 
ice surface and has to be subtracted from any ice thickness estimate. 

The resulting ice thickness distributions of all combined surveys are 
shown in Figure 3.25. If compared to the results of the airborne surveys, 
ground-based EM data shows significantly thicker sea ice. This can be 
related to a selection bias of the ice station work, because only the 
thickest floes were suitable candidates. More typical floes did not have 
the structural strength to withstand the manoeuvres of Polarstern and 
their high density of open melt ponds and cracks made safe working with 
heavy equipment impossible. However, if compared to the ground-based EM 
surveys from 2007 (Polarstern cruise ARK-XXII/2), the thickness 
distributions are very similar again with identical modal thicknesses of 
1.3 m (Airborne survey: 0.9 m). 


Fig. 3.25: Resulting sea ice thickness distribution from all ground-based 
           EM surveys in comparison to the airborne EM surveys (left) and 
           ground-based surveys from 2007 (right).



3.4  Deployment of drifting buoys 

     Stefan Hendricks                       Alfred-Wegener-Institut 


Objectives 

Continuous measurements of basic physical parameters, such as air 
temperature and pressure, ice drift and ice thickness, are sparse in the 
vast area of the sea ice covered Arctic Ocean. One method to close this 
data gap is the use of autonomous drifting stations, which report their 
data over a satellite communication network in near real-time and thus do 
not need to be recovered. Such measurements are especially rare in the 
Siberian Arctic, where the predominant drift patterns export drifting 
stations with the Transpolar Drift Stream in the central Arctic and 
ultimately into Fram Strait or the Beaufort Gyre. In addition, drifting 
stations may be destroyed by sea ice deformation events and by activities 
of polar bears. Therefore, cruises into the Siberian Arctic, like ARK-
XXVI/3, provide key opportunities to repopulate this region with drifting 
ice buoys. The main objective of these buoy deployments, which are 
coordinated by the International Arctic Buoy Program (IABP), is to obtain 
time series of physical parameters of the air-sea ice interface as input 
dataset for modelling efforts and remote sensing data products. 

Work at sea 

Deployments were carried out during regular ice stations, by dedicated 
landings with the helicopter on ice floes up 40 miles to the side of the 
cruise track and on ice floes, which were accessed by the mummy chair of 
Polarstern. 

We deployed 11 drifting buoys of different design with a special regional 
emphasis on the Siberan Arctic (Fig. 3.26 and Tab. 3.8). Surface Velocity 
Profilers (SVP) from MetOcean Data Systems transmits GPS positions and 
surface temperatures. All buoys were deployed on the ice surface. The 
temperature recording however, either represents the ice, snow or air 
temperature, depending on the orientation of the sphere-shaped buoy body. 
In total, 7 SVPs were deployed for Meteo France and the Norwegian Polar 
Institute. 

The second buoy type (Ice Beacon, MetOcean Data Systems) was deployed on 
three locations towards the end of the cruise. The IceBeacon (ICEB) 
transmits position, surface temperature and air pressure, where the 
sensors are mounted on a mast in a height of 1.2 m above the ice surface. 
The buoys are anchored in the ice in a roughly 1-meter deep hole. Ice 
Beacons are equipped with flotation collars, which allows the buoy to 
survive even total ice melt. 


Fig. 3.26: Location and date of deployments and WMO ID’s of sea ice 
           buoys. The three buoy types are marked by different symbols.


Tab. 3.8: Type, date and position of buoy deployments during the ARK-
          XXVI/3. Sea ice thickness was not measured on all deployment 
          sites. ID of the World Meteorological Organization and 
          International Mobile Equipment Identity (IMEI) is given if 
          provided. 

Buoy  Argos   WMO        IMEI          Date      longitude  latitude  Ice 
Type   ID     ID                                                      Thick- 
                                                                      ness  
————  —————  —————  ———————————————  ——————————  —————————  ————————  ——————
SVP     -    26553  300234010826150  14.08.2011    59,4167  85,9833   > 2m  
SVP     -    26554  300234010828610  22.08.2011    55,5500  89,8500   2.9 m  
SVP     -    48602  300234010826110  31.08.2011  -137,2690  85,0348    - 
SVP     -    48611  300234010826630  07.09.2011  -176,9375  83,8559    - 
SVP     -    25616  300234010824160  12.09.2011   131,4783  83,8703    - 
SVP     -    25617  300234010829160  15.09.2011   110,2440  82,3671   
SVP     -      -    300034013353520  12.09.2011   131,0500  84,4519    - 
(NPI) 
ICEB    -      -    300034013409520  10.09.2011   150,1830  84,6900    - 
ICEB  57009  25618         -         12.09.2011   131,8713  83,3456    - 
ICEB  57010  25619         -         17.09.2011   103,1983  81,3543   
IMB     -      -           -         09.09.2011   166,4240  84,7950   1.1 m  


The third buoy type was an Ice Mass Balance Buoy (IMB), provided by the 
Norwegian Polar Institute. This buoy type requires the installation of 
three main components: 1) The central electronic, power and communication 
unit, 2) A mast with two ultrasonic pingers, which measure the range from 
the sensors to the top snow/ice surface from above and the lower ice 
surface from below and 3) One mast with air temperature and pressure 
sensors. With the measured initial sea ice thickness and snow depth 
values, this buoy type is able to monitor snow accumulation, ice growth 
as well as top and bottom melt in the following summer and link these 
measurements to local meteorological conditions. This installation was 
done during the ice station on September 9 on a piece of multiyear sea 
ice as part of a multi-buoy station with additional oceanographic buoys. 
EM31 ice thickness surveys were conducted prior to the deployment to 
identify a suitable site with a target thickness of less than 2 m. In 
addition, and to protect the buoy from damage by ice deformation, the 
deployment site ideally had to be in a centre of a floe without any melt 
ponds our other weak ice structures. The only suitable place however was 
found on ice with a thickness of 1.1 m. 

The buoy activities in the Arctic Ocean are linked together in the 
International Arctic Buoy Program (IABP). Science data as well as the 
operational range of buoys with a WMO Id can be obtained there. 



3.5  Routine sea ice observations 

     Priska Hunkeler                        Alfred-Wegener-Institut 


Objectives 

Hourly standardized visual ice observations from the bridge of Polarstern 
were carried in the ice-covered part of the cruise track to characterize 
and document different states and specific features of the sea ice cover. 
Besides the visual observation photos for documentation were taken in 
three different directions. For comparison with other acquired data 
during this and prior cruises the routine visual observation of sea ice 
are essential. Furthermore, visual observation represents the longest 
time series of sea ice conditions in the Arctic. But also as database by 
its own the data acquired show interesting results as presented in this 
section. 

Work at sea 

Every hour during day and sporadically during night, depending on 
observers working shifts, the ice observation was carried out by 27 
persons. A computer was installed on the bridge, where the observations 
directly could be entered by the observer. The observation followed the 
ASPeCt (Antarctic Sea Ice Processes and Climate) protocol as in 2007 
(ARK-XXII/2). The recording software was taken from Worby (1999). 

General data (date, UTC time, ship coordinates) were copied from the 
general data display (DSHIP). Then total ice concentration and the state 
of open water (e.g. "Narrow breaks 50-200 m") were filled into the 
protocol. Maximal three different ice types (e.g. "first-year 0.3-0.7 m" 
or "multi-year floes") were then described, starting with the thickest 
one. For each of the ice types ice concentration, ice thickness, floe 
size, topography (e.g. "level ice" or "consolidated ridges") with areal 
coverage and average sail heights, snow type (e.g. "cold old snow") and 
snow thickness were chosen from a drop-down list. By convention the 
comment line was used for melt pond concentrations, since no dedicated 
melt pond classifications exist in ASPecT. 

The spatial variability was taken into account by taking the average 
between observation to port side, ahead and to starboard side. Ice 
thicknesses of tilted floes were estimated by observing a stick attached 
to the ships starboard side (Fig. 3.27). 


Fig. 3.27: Observation from the bridge: Ruler to obtain the thickness of 
           tilted sea ice when the ship is breaking ice. This broken floe 
           has a thickness of approximately one meter. 


Meteorological data (sea temperature, air temperature, true wind speed, 
true wind direction, visibility) were also copied from the bridges 
computer and filled into the protocol. Cloud cover and actual weather 
were estimated by the observer. Three photos were then taken (view to 
port side, ahead and to starboard side, Fig. 3.28 and 3.30) and their 
numbers were filled into the protocol. 


Fig. 3.28: Examples of ice observation photos: good visibility, snow-free 
           sea ice (August 18, 2011 01:00 UTC) taken from the bridge of 
           Polarstern. View to port side, ahead and to starboard side. 
           Good visibility, snow-free melt ponds.

Fig. 3.29: Examples of ice observation photos: bad visibility, snow-
           covered sea ice<s (September 10, 2011 07:00 UTC) taken from 
           the bridge of Polarstern. View to port side, ahead and to 
           starboard side.


The software was developed for Antarctic sea ice, what caused some 
problems. Because there are no melt ponds in the Antarctic the comment 
line had to be used for that purpose, what resulted in some inconsistent 
entries. Further, thin multi-year ice (<2 m) was observed. But as this 
not foreseen in the Antarctic, an error showed up in the software and a 
minimum of 2 m had to be entered. 

Depending on the weather condition there was more or less space for 
interpretation. Snow on melt ponds complicated the observation, as Figure 
3.31 and 3.32 are indicating. Also, the personal view and estimation of 
the different observers has to be kept in mind. 

Preliminary results 

The ice observations were carried out between August 9, 2011 when 
Polarstern entered ice-covered waters in the North of Franz Joseph Land 
till September 19, 2011 passing last floes when Polarstern left the ice 
zone the Laptev Sea. The ice conditions were favourable for ship 
operation. Only after the North Pole, Polarstern turned westwards because 
of severe ice conditions. The Alpha Ridge couldn't be studied as planned 
and the ships track was relocated to the one of ARK-XXII/2 in 2007. In 
total 324 observations at 42 days were carried out, what are 7.7 
observations per day. During station work under unchanging ice conditions 
no data was recorded, what gives a more representative distribution of 
observations. 

Ice types 

The mean total ice concentration was 86.5%. Total ice coverage could be 
observed mainly when refreezing started and new ice was built after 
August 23, 2011. As Polarstern went further south open water could be 
observed again more frequent. First multi-year ice was observed at August 
14, 2011 on the way to North Pole. After September 5, .2011 the 
observation of multi-year ice was less frequent as Polarstern went to the 
west. In Figure 3.30 photos of new-built, brash, first-year and multi-
year ice are illustrated and in Figure 3.31 the occurrence in per cent is 
shown. 


Fig. 3.30: Different ice types. Above: Left: New-built ice, finger 
           rafting (August 24, 2011 08:00 UTC). Right: Brash ice and 
           open water September 18, 2011 21:00 UTC. Below: Left: First-
           year ice August 23, 2011 19:00 UTC, Right: Multi-year ice 
           August 14, 2011 10:00 UTC. 

Fig. 3.31: Ice type occurrence of multi-year-ice (green), first-year ice 
           (blue), young ice (grey), brash ice (red) and open water 
           (white) observed from the bridge of Polarstern between August 
           9 and October 19 2011. 


Ice thickness and topography 

The average level ice thickness of multi-year ice was 230 cm and of 
first-year ice 96cm (Tab. 3.9), what is in good agreement with the EM-
data. Multi-year ice thickness is overestimated due to the required 2 m 
(green in Fig. 3.32). Newly formed ice was mainly observed as nilas or 
thin young grey ice (Tab. 3.10). 


Tab. 3.9: Sea ice thickness observation of first-year and multiyear ice 
          classes in centimetres: Number of observations and thickness 
          statistics. 

Ice type  First-year  First-year  First-year  First-year  Multi-year  Brash
           30-70cm     70-120cm     >120cm     all data     >200cm     ice  
————————  ——————————  ——————————  ——————————  ——————————  ——————————  ——————
Number of     58         206          45          309        146         5 
observations 
Minimum [cm]  30          70         120           30        200        10  
Maximum [cm]  70         120         300          300        500        40  
Average [cm]  54          95         157           96        230        30  



Tab. 3.10: Sea ice thickness observation of thin ice classes in 
           centimetres: Number of observations and thickness statistics. 

Ice type      Frazil  Shuga  Grease  Nilas   young grey    young grey white
                                            ice (10-15cm)   ice (15-30cm)  
————————————  —————— ——————  ——————  —————  —————————————  ————————————————
Number of ob     1      1       4      59        31               9
  servations   
Minimum [cm]     2      2       1       1        10              15  
Maximum [cm]     2      2       2      10        15              30  
Average [cm]     2      2       2       6        12              22  



Fig. 3.32: Ice thickness of multi-year-ice (green), first-year ice 
           (blue), young ice (grey) and brash ice (red) observed from 
           the bridge of Polarstern between August 9 and October 19, 
           2011. Dashed lines show the mean first-year and multi-year 
           ice of 96 and 230 cm. 


The main topography type observed were "old, weathered ridges" with 43%, 
"level ice" with 32% and "consolidated ridges" with 17%. Only few per 
cent of "new unconsolidated ridges", "new ridges filled with snow" and 
"finger rafting" were observed. In general, 52% of the ridges covered an 
ice floe with 0-10% and 21% with 10-20%. 45% of the ridges reached an 
average sail height of 0.5m, 36% of 1m and 14% of 1.5m. As the view was 
from above on the ice the sail height may be underestimated. 

Melt ponds and snow coverage 

Melt pond concentrations on ice floes of first-year and multi-year ice 
were estimated. Mean melt pond concentration on multi-year floes was 20% 
and on first-year floes 46% (green and blue lines in Fig. 3.33). Because 
not all observers divided between melt ponds on first- and multi-year 
ice, their estimated average values are shown in black. At the end there 
were fewer observations of melt ponds, because it was difficult to do an 
estimation of a floe covered with snow (Fig. 3.29). The amount of 
increased brash ice at the end of the cruise may also lead to fewer 
observations. Snow coverage on first-year ice is in average 3.7cm high, 
starting from first snow observation of August 13, 2011 the average snow 
thickness is 4.1cm. 


Fig. 3.33: Melt pond concentration of multi-year-ice (green), first-year 
           ice (blue) and in average (black), observed from the bridge of 
           Polarstern between August 9 and October 19, 2011. Dashed lines 
           show the mean first-year and mean multi-year melt pond 
           concentration of 46 and 20%. 



3.6 References 

Petrich, C., Eicken, H. 2010. Growth, Structure, and Properties of Sea 
    Ice, in Sea Ice, edited by D. N. Thomas and G. Dieckmann, pp. 23-78, 
    Blackwell Science, Oxford, UK. 

Worby, A. P., 1999. Observing operating in the Antarctic sea ice: A 
    practical guide for conducting sea ice observations from vessels 
    operating in the Antarctic pack ice. 


Acknowledgements 

We thank the crew of the Polarstern, FIELAX, and the team of Heli-Service 
International for their excellent collaboration. The hourly sea ice 
observation data only exists, because of all the volunteers. Many thanks 
to Ursula Schauer who made this cruise possible. 




4.  PHYSICAL OCEANOGRAPHY 

    Ursula Schauer(1), Benjamin Rabe(1),    1 Alfred-Wegener-Institut 
    Bert Rudels(2), Sergey Pisarev(3),      2 Department of Physics, 
    Andreas Wisotzki(1}, Hiroshi              University of Helsinki
    Sumata(1), Ian Waddington(4),             and Finnish Meteorological 
    Oliver Zenk(5)                            Research Institute 
                                            3 Shirshov Institute of 
                                              Oceanology 
                                            4 International Arctic 
                                              Research Institute 
                                            5 OPTIMARE Marine 
                                              Messsysteme GmbH & Co. KG 


Background and Objectives 

Not only sea ice coverage, but also the circulation and water mass 
properties of the Arctic Ocean have been changing considerably during the 
past decades. The waters advected from the Atlantic and the Pacific 
became much warmer and, for the Atlantic part, saltier and on the other 
hand much more fresh-water was stored recently in the Arctic Ocean than 
in the 1990s. To understand the underlying processes and the impact of 
these changes their further evolutions need to be observed. Therefore, 
the aim of the oceanographic part of this cruise was to document and 
quantify the present state of the water mass distribution and circulation 
in the Eurasian and northern Canadian basins. In the context with 
appropriate modelling, the observations will be fundamental to 
distinguish between variability and long-term trends in the Arctic. 

In the Arctic, the imported ocean waters are subject to transformations 
through cooling, freezing and melting. The pathways and properties of the 
two branches of warm Atlantic Water, flowing into the Arctic Ocean 
through the Fram Strait and the Barents Sea and travelling presumably in 
cyclonic loops along the continental slopes and ridges, however vary and 
so does the flow of Pacific Water. 

In the central Arctic both inflows, even though getting warmer, are 
inhibited from releasing their heat to the atmosphere by the thick layer 
of fresh water, which is supplied by continental runoff and ice or 
meltwater. However, the variable distribution of the fresh water may 
facilitate some heat release in certain areas. E.g. the recent 
convergence of fresh water in the central Arctic may for dynamical 
reasons lead to a weakening of the stratification along the warm boundary 
current at the rim of the basins. Changes may also occur from the 
different wind mixing with and without ice cover and the fact that now 
large areas have longer seasons without sea ice. 

There are also indications of a (recent) change of the pathways of the 
Atlantic Water. The warmer branch from Fram Strait seems to return 
already in the Nansen Basin back to the Atlantic sector and also the flow 
of Barents Sea water into the Canadian Basin may be reduced in the 
context with the strengthening of the Beaufort Gyre. Such changes will 
affect the properties of the water returning to the North Atlantic and 
hence directly or indirectly influence the Atlantic meridional 
overturning circulation.  

To address these questions hydrographic sections were recaptured that 
were taken in the Eurasian Basin during the cruises with Polarstern and 
Oden since the early 1990s. To extend the observational range of the ship 
survey in space and time, autonomous, ice-based buoys as well as bottom-
moored observatories were deployed. The ice-tethered buoys were deployed 
in upstream regions of the Transpolar Drift so that they would cross the 
Eurasian Basin. The moorings were deployed near the south-eastern end of 
Gakkel Ridge to obtain first year-round data of the return flow in the 
Eurasian Basin. 

Work at sea 

CTD casts and ship-borne ADCP measurements 

Full-depth sections and several shallower casts of temperature and 
salinity were obtained by using three Conductivity Temperature Depth 
(CTD) systems (Fig. 4.1). Two of these systems, an XCTD-system and a 
newly developed light full-depth CTD-system, enabled profiles to be taken 
from ice floes far from the ship that were reached by helicopter. This 
extended the observational range. In total, 228 CTD profiles were taken. 


Fig. 4.1: Seafloor bathymetry with locations of CTD stations.


136 profiles were taken at 111 stations with a standard CTD/rosette water 
sampler system from Sea-Bird Electronics Inc. The SBE9+ CTD (S/N 937) was 
equipped with duplicate temperature (S/N 2929 and 1373) and conductivity 
(S/N 2470 and 3290) sensors and was connected to a SBE32 Carousel Water 
Sampler (S/N 718) with 24 12-liter bottles.  Additionally, a Benthos 
Altimeter (S/N 46611 and 47768), a Wetlabs C-Star Transmissometer (S/N 
1198), a Wetlabs FLRTD Fluorometer (S/N 1853) and an SBE 43 dissolved 
oxygen sensor (S/N 1834) were mounted on the carousel. The SBE 43 
contains a membrane polarographic oxygen detector. The algorithm to 
compute oxygen concentration requires also measurements of temperature, 
salinity and pressure which are provided by the CTD system. 

To calibrate the oxygen profiles water from CTD rosette bottles was 
measured onboard with Winkler titration; in addition, dissolved oxygen 
water samples were measured for other groups on-board, giving a total of 
534 measurements. 

208 salinity samples for the calibration of the conductivity sensors were 
taken from rosette bottles and analysed with a recently developed 
salinometer manufactured by Optimare Sensorsysteme AG (Bremerhaven, 
Germany) with Standard Water Batch p152. Further samples were taken by 
other groups on-board for chemical and biological analysis. 

A XCTD-1, by Tsurumi-Seiki Co. Ltd. (Yokohama, Japan) was used to obtain 
88 CTD casts up to 1100 m water depth while underway from the ship and 
from ice floes reachable by helicopter. The system consisted of a 
launcher for expendable CTD probes and a mobile deck-unit for data 
acquisition. The probe sinks down with constant velocity measuring 
temperature and conductivity. 

A third system utilized a new light-weight, mobile winch with a thin 
rope. This winch has been developed by Gereon Budus at AWI and was tested 
during this cruise for the first time. The winch was operated with a 
Seabird SBE-19 sensor package (S/N 6666) mounted together with a buoyancy 
package (ceramic spheres in plastic casing) to minimize the load for the 
winch motor. Four profiles were conducted successfully with this system. 

One advantage of the mobile CTD system is that it can be used away from 
the influence of the ship that may destroy the original structure of the 
upper ca. 15 meters of the water stratification, particularly when using 
the thrusters during station work. Two profiles from the mobile CTD at 
the Gakkel Ridge showed mixed-layer depths of between 15 to 20 m, with a 
relatively uniform temperature and salinity structure of the layer below 
4 m (Fig. 4.2). Layers shallower than 4 m, possibly containing melt 
water, could not be sampled as the system had to be deployed and 
recovered together with the buoyancy package above. 


Fig. 4.2: Comparison of mobile CTD (on the ice floe, green) and ship CTD 
          (blue) profiles taken at station 209-4. The crosses represent 
          values from the mobile CTD upcast, otherwise downcasts are 
          shown (dots). 


Underway measurements with a vessel-mounted narrow-band 150 kHz ADCP from 
TRD Instruments and with two Sea-Bird SBE45 thermosalinographs were 
conducted to supply water current velocity and temperature / salinity 
data, respectively. The thermosalinographs are installed in 6 m depth in 
the bow thruster tunnel and in 11 m depth in the keel, although the bow 
system was switched off while the ship was crossing sea ice. The salinity 
of both instruments was controlled by taking water for calibration. The 
ADCP worked well throughout most of the cruise with very few data gaps. 

Data from the ship rosette CTD, underway CTD and the ADCP will ultimately 
be available through the PANGAEA database (World Ocean Data Center #4). 
In order to provide year-round autonomous measurements, ice-tethered 
platforms with various instrumentation and several bottom mounted 
moorings were deployed, as detailed in the following sections. 

Bottom moored arrays 

During the cruise 3 moorings were recovered and 5 moorings were deployed. 

Deployment of moorings near the Gakkel Ridge: 

To obtain timeseries of velocity, temperature, salinity and ice thickness 
as well as samples of sinking particles in the Eurasian Basin return flow 
of Atlantic Water, five moorings were deployed at two locations near the 
Gakkel Ridge, one in the Amundsen Basin and one in the Nansen Basin. The 
recovery of these mooring is planned for the Polarstern expedition in 
2012. The details of the moorings are given in Fig. 4.18 to 4.21. 

Two mooring pairs with identical design and one extra mooring were 
deployed on either side of the Gakkel Ridge (Fig 4.3): One mooring of 
each pair carries a profiling CTD system, designed by Gereon Budus at 
AWI, to give nearly full-depth profiles of temperature and salinity once 
a day. The other mooring has several current meters. Two of them are TRD 
Instruments ADCP that measure the shear profiles of the upper 800 m. Due 
to close vicinity to the magnetic pole, the horizontal magnetic field 
intensity falls below the value required to obtain accurate measurements 
by the ADCP internal compass. However, the vertical shear will be 
accurate within each profile, as the data is recorded in instrument 
coordinates, and the ping interval was set to near minimum to minimize 
the influence of angular movement of the ADCP within each ensemble. 
Further instrumentation included two Aandera current meters to measure 
current speed at depths not covered by the ADCPs, three Seabird SM 37 for 
point measurements of salinity, temperature and depth and an upward 
looking sonar to measure ice draft. Sediment traps are located at 200 m 
depth and near the sea floor. Only on the Amundsen Basin side of the 
Gakkel Ridge, an additional profiler for temperature/salinity was 
deployed to measure the upper 200 m. The deployments were on fairly level 
sea floor, and the region of the deployments was ice-free. 

Three moorings belonging to the Russian-US program Nansen and Amundsen 
Basins Observational System (NABOS, http://nabos.iarc.uaf.edu) were 
successfully recovered at the continental margin north of the Laptev Sea 
and north of Franz Josef-Land. The recovery was extremely difficult, due 
to failure of the bottom releases (double at each mooring). Only the 
experience and skill of the Polarstern crew allowed exact location of the 
moorings using the fish finder (echosounder) and recovering them using a 
tugging method, whereby the mooring is encircled with a line between the 
ship and a dinghy and subsequently pulled toward the ship. The mooring 
north of Franz Josef Land was recovered in partial ice cover, whereas the 
two moorings north of the Laptev Sea were in ice-free waters. With the 
recovery, existing observation time series at the respective locations 
could be extended by up to 4 years. 

Ice-tethered buoys 

In order to obtain year-round measurements of ocean temperature, 
salinity, velocity, oxygen and bio-optical parameters as well as air 
temperature, pressure and wind velocity, ice-tethered platforms with 
various instruments were deployed. They consist of a sub-ice sensor 
system that is connected by a cable to a surface unit that transmits the 
data to shore via satellite. Since they drift with the host ice floe, 
they have the potential to provide observations over a substantial region 
of the Arctic Ocean. Five different types of ocean buoys were deployed, 
all of which record their geographic position at time of measurement: 

3  ITPs (Ice-Tethered Profiler) equipped with Seabird CTDs that will  
   sample temperature, salinity and dissolved oxygen profiles once per 
   day between the surface and 760 m water depth, 

1  Bio-ITP, equipped as the other ITPs, but with a bio-optical package, 
   measuring Photosynthetically Active Radiation (PAR) and Chlorophyll 
   Fluorescence, 

2  POPS (Polar Ocean Profiling System) equipped with Seabird CTDs that 
   will sample temperature and salinity profiles once per day between the 
   surface and 800 m water depth, and meteorological sensors for surface 
   air temperature and barometric pressure, 

1  ITAC (Ice-tethered Acoustic Current profiler) consisting of a surface 
   unit connected to an RDI ADCP (150 kHz, Quartermaster) that measures 
   the velocity profile of the upper 300 m every two hours, 

1  ITBOB (Ice-Tethered Bio-Optical Buoy) consisting of a surface unit 
   with GPS and satellite communication, connected to three YSI probes 
   with radiance (PAR) sensors, temperature and conductivity probes, an 
   oxygen optode, a fluorescence probe, one 5 m long thermistor chain in 
   and under the ice, and an additional PAR sensor. 

Further autonomous buoys are described in the Sea Ice Physics section. 

In total, 7 ocean buoy systems were deployed on 5 ice floes (crosses Fig. 
4.3). One further POPS system was deployed but had to be subsequently 
recovered due to hardware problems (diamond in Fig. 4.3). 


Fig. 4.3: Map of CTD-profiling buoy (ITP and POPS) locations at 
          deployment (pentagons) and on September 24 (crosses). Asterisks 
          show the locations of other ITP and POPS transmitting data in 
          the Arctic Ocean at that time. The colour scale indicates the 
          sea ice concentration (%; AMSRE). The black line represents the 
          cruise track. The first ocean buoy deployment was a POPS. The 
          diamond represents a further POPS that was recovered subsequent 
          to deployment because of a technical failure. The locations of 
          the bottom mounted moorings are shown by a white X (AWI mooring 
          cluster) and a white circle (NABOS moorings). 


Four ITP / Bio-ITP systems manufactured by Woods Hole Oceanographic 
Institution (WHOI) in Woods Hole (Massachusetts, USA) measure twice daily 
temperature/ salinity/depth/oxygen profiles with 1 Hz (nominally 0.25 m) 
vertical resolution between 8 and 760 m using a profiling CTD unit 
(Seabird Electronics, Inc. model 41CP) on a wire tether and an inductive 
modem to communicate the data to a surface unit (SU). The ITP SU records 
GPS position and relays all data via an Iridium satellite modem 
connection to a server at WHOI. The ITPs are manufactured by WHOI with a 
profiler from McLane Research Laboratories (Falmouth, Massachusetts, 
USA). The Bio-ITP measures, in addition, photosynthetically active 
radiation and chlorophyl fluorescence throughout the profiles. Two ITP 
were provided by AWI and the remaining ITP and one Bio-ITP by WHOI. 

Two systems similar to the ITP, Polar Ocean Profiling Systems (POPS) 
manufactured by MetOcean Data Systems (Dartmouth, Nova Scotia, Canada) 
were also deployed. The POPS were configured to measure 
temperature/salinity/depth profiles at the same vertical resolution as 
the ITP systems and surface atmospheric temperature and barometric 
pressure. The data sampling intervals for meteorological and ocean 
profiling data were set to be 3 hours and 1 day, respectively. However, 
it was found that the newly incorporated NOVA profiler shows about 4 m 
gaps at irregular intervals due to design limitations of the profiler 
controller. 

An Ice Tethered Acoustic Current profiler (ITAC) by Optimare 
Sensorsysteme AG (Bremerhaven, Germany), measuring ocean current velocity 
profiles from 10 m under the ice to a depth of around 300 m, incorporates 
an ADCP mounted about 4 m from the top of the ice floe. The ADCP is 
rigidly connected via a stainless steel pole with a wooden beam on the 
surface. A cable provides the electrical connection to a surface unit 
with a GPS receiver and an Iridium modem. To allow the recording of the 
ADCP orientation even in regions of low horizontal magnetic field 
strength, two further GPS are positioned about 98 m in opposite 
directions from the surface unit and in line with the wooden beam and the 
ITAC SU. Data are relayed daily via the Iridium Short Burst Data (SBD) 
message service to an email address at Optimare. The communication is bi-
directional and also allows setting of data sampling parameters via SBD 
messages, both for the ADCP and the ITAC SU (e.g. GPS sampling rate). 

The ITBOB (Ice-Tethered Bio-Optical Buoy) consisted of a surface unit with 
GPS and satellite communication, connected to three YSI probes with 
radiance (PAR) sensors, temperature and conductivity probes, an oxygen 
optode and a fluorescence probe. The three packages were deployed in the 
ice, and 20 cm as well as 1m under the ice flow. In addition, a 5 m long 
thermistor chain was deployed in and under the ice, and a PAR sensor was 
connected to the surface unit. Results from the first 6 weeks of 
deployment showed a change in bio-optical parameters along with a rapid 
temperature decrease and diminishing PAR in mid-September. During the 
initial phase the freeze-in effect of the YSI 1 module into the ice floe 
showed in rapidly increasing salinities and changing oxygen 
concentrations. The PAR sensors showed strong daily variations in light 
availability. Already in mid-September only a limited amount of light is 
available in the ice and below the ice (max 2 µmol photons m^(-2) s^(-1)), 
which was further decreasing with time. First trends in oxygen, 
temperature and salinity were observed. Oxygen concentrations increased 
despite increasing salinity, probably dominated by the decreasing 
temperature. Thus, already this short-term continuous sensor record 
provided valuable information on physico-chemical gradients and behaviour 
within the ice and in the transition zone between the sea ice and the open 
water. 

All ocean buoys were distributed on six sites, of them on the section 
crossing the North Pole, but most on the section from the Canadian Basin 
to the Laptev Sea in order to maximise their expected drifting time and 
range (Fig. 4.3). One site was named a 'Super Buoy station' where an ITP, 
ITAC and ITBOB were deployed on the same ice floe. All ocean buoys were 
deployed while the ship was docked to the ice floe. 

The search for suitable floes was often hampered by bad weather which 
made helicopter use impossible, so that several ice floe searches had to 
be carried out from the ship. Finally, for all buoys multi-year ice floes 
with large ridges and ice thicknesses of more than 1 m were found. 

Performance and failures 

The autonomous ocean buoys drifted during the cruise since deployment 
(Fig.4.3). The POPS data will be processed in-house at AWI, but will be 
made available in public databases, either ARGO or PANGAEA, in the 
future. The ITP data can be downloaded from the WHOI ITP web site. 

So far, one POPS sent profiles until September 17, but no profiles 
thereafter. One of the ITPs suffered a technical failure of the inductive 
modem and has not sent any profiles. Two further ITPs have stopped 
sending profiles toward the end of 2011, one due to grounding at shallow 
topography. The remaining ITP is still obtaining profiles into 2012. 

The ITAC operated fine, but an initial configuration could not be 
optimized due to bad weather during the deployment, forcing people to go 
back to the ship before a final configuration and testing could be 
performed on the ice subsequent to deployment. Remote configuration is 
generally possible and was attempted during the cruise. However, so far 
technical problems have prevented the system from accepting the new 
configuration parameters. 

One ITP system, deployed in the Makarov Basin, failed the final inductive 
modem test for communication between the surface unit and the profiler. 
However, the conditions and the lack of a motorised system prevented 
recovery. To date, the system has reported status and position but no 
ocean profiles. 

One of the POPS systems had a similar inductive modem test failure but 
could be recovered using one of the ship's capstans, as the deployment 
site was only about 100 m from the ship's stern. The two POPS systems had 
been supplied with different mooring cables: one system had a wire with, 
presumably, a polypropylene or hard PVC jacket, the other system with, 
seemingly, a polyethylene jacket (the wire specification by Metocean 
stated PVC for all wire jackets). The wire of the second system showed 
problems coming off the drum, as it was only loosely reeled on, and the 
jacket was breaking in several places during the deployment. These parts 
of the wire jacket were fixed with tape, but the test for the inductive 
modem communication between the surface unit and the profiler failed 
after deployment. 


Preliminary results 

Sections of temperature, salinity and oxygen profiles are shown in 
Figures 4.4 to 4.17. 

North of Franz-Josef-Land, the warm Atlantic Water, flowing into the 
Arctic Ocean via the Fram Strait, is clearly visible near the shelf break 
with temperatures up to 2.5°C (Section 1, Fig. 4.10) and salinities 
around 34.96 (Fig. 4.11). The maximum temperature has decreased by about 
0.5°C, relative to measurements at this location in 2007. The cooling 
resumes a respective temperature drop observed after 2006 in the West 
Spitsbergen Current in Fram Strait where the inflow properties are 
recorded by a mooring array, maintained by AWI. In Fram Strait, 
subsequent to 2008, the Atlantic Water temperature increased again 
slightly until 2011. Hence, the observed cooling at the Eurasian 
continental margin appears to be an intermittent anomaly propagating with 
the boundary current from the subarctic Atlantic. 

The cooling signal has already spread up to the eastern Nansen Basin 
north of the Laptev Sea, where near at the Gakkel Ridge maximum 
temperatures were around 1.5°C (Section 3, Fig. 4.10), 0.5°C cooler than 
at nearby stations in 2007. Also, the salinity maximum has decreased 
north of the Laptev Sea since 2007 by about 0.05 (Section 3, Fig. 4.11). 

If the low salinity observed north of the Laptev Sea is primarily due to 
intense mixing of the Barents Sea and Fram Strait branches of the AW 
inflow to the Arctic Ocean or if the warmer and more saline Fram Strait 
branch returns to the Fram Strait in the Nansen Basin before reaching the 
region north of the Laptev Sea is still an open question. 

Deep layers 

The deep water in the Nansen Basin was found to be about 10-3°C warmer 
than in 2007. This is close to the accuracy of the temperature sensors 
and an order of magnitude less than the warming of 0.02°C observed 
between 1996 and 2007. 

The results of all CTD casts are still preliminary, as the final 
calibration using the salinity and temperature data was done after the 
cruise. The ADCP data will be processed after the cruise for further 
analysis in conjunction with the CTD data. 

Integration to national and international programmes 

The oceanographic work of the cruise was supported by the current HGF 
(Helmholtzgemeinschaft) Programme and by the project "The North Atlantic 
as Part of the Earth System: From System Comprehension to Analysis of 
Regional Impacts" funded by the German Federal Ministry for Education and 
Research (BMBF). Instrumental work was also supported by the Japan Agency 
for Marine Earth Science and Technology (JAMSTEC) and by the Woods Hole 
Oceanographic institution (WHOI). The ice-based platforms contribute to 
the Hybrid Arctic/ Antarctic Float Observation System (HAFOS) and the 
"International Arctic Buoy Programme" (http://iabp.apl.washington.edu/). 


Fig. 4.4: Potential temperature (°C) along Section 1, station numbers on 
          top. Plots for both full-depth and only the top 400 m are 
          shown.

Fig. 4.5: Salinity along Section 1, station numbers on top. Plots for 
          both full-depth and only the top 400 m are shown.

Fig. 4.6: Dissolved oxygen (ml/l) along Section 1, station numbers on 
          top. Plots for both full-depth and only the top 400 m are 
          shown.

Fig. 4.7: Potential temperature (°C) along Section 2, station numbers on 
          top. Plots for both full-depth and only the top 400 m are 
          shown.

Fig. 4.8: Salinity along Section 2, station numbers on top. Plots for 
          both full-depth and only the top 400 m are shown.

Fig. 4.9: Dissolved oxygen (ml/l) along Section 2, station numbers on 
          top. Only the top 400 m are shown.

Fig. 4.10: Potential temperature (°C) along Section 3, station numbers on 
           top. Plots for both full-depth and only the top 400 m are 
           shown.

Fig. 4.11: Salinity along Section 3, station numbers on top. Plots for 
           both full-depth and only the top 400 m are shown.

Fig. 4.12: Potential temperature (°C) along Section 4, station numbers on 
           top. Plots for both full-depth and only the top 400 m are 
           shown.

Fig. 4.13: Salinity along Section 4, station numbers on top. Plots for 
           both full-depth and only the top 400 m are shown.

Fig. 4.14: Potential temperature (°C) along Section 5, station numbers on 
           top. Plots for both full-depth and only the top 400 m are 
           shown.

Fig. 4.15: Salinity along Section 5, station numbers on top. Plots for 
           both full-depth and only the top 400 m are shown.

Fig. 4.16: Potential temperature (°C) along Section 6, station numbers on 
           top.

Fig. 4.17: Salinity along Section 6, station numbers on top. Plots for 
           both full- depth and only the top 400 m are shown

Fig. 4.18: Schematics of the mooring A1-1 deployed in the Amundsen Basin 
           (north-eastern white cross in Fig. 4.3.)

Fig. 4.19: Schematics of the mooring A2-1 deployed in the Amundsen Basin 
           (north-eastern white cross in Fig. 4.3.

Fig. 4.20: Schematics of the mooring A3-1 deployed in the Amundsen Basin 
           (north-eastern white cross in Fig.4.3).

Fig. 4.21: Schematics of the mooring N1-1 deployed in the Nansen Basin 
           (south- western white cross in Fig.4.3).

Fig. 4.22: Schematics of the mooring N2-1 deployed in the Nansen Basin 
           (south- western white cross in Fig.4.3).








5.  GEOCHEMISTRY 

5.1  The carbonate system 

     Adam Ulfsbo and Ylva Ericson,          University of Gothenburg, 
     PI Leif Anderson* not on board         Department of Chemistry, 
                                            Sweden 

Updated: December 14th, 2015 

Abstract 

This document outlines the procedures followed in the collection and 
determination of pH, DIC and TA of seawater samples during the F/S 
Polarstern cruise ARKXXVI/3, also known as TransArc (Trans-Arctic survey 
of the Arctic Ocean in transition). From 5. August (Tromsø) to 7. October 
(Bremerhaven), a total of 1254 samples were analyzed from 56 stations. 
Seawater sam-ples were sampled throughout the water column according to 
Dickson et al. (2007) and analyzed on board within hours. Data quality is 
discussed. Resulting data is correctable through the use of certified 
reference material (CRM), after which data is deemed to be of reasonably 
high quality. All samples and data were sampled, analyzed and processed 
by Adam Ulfsbo and Ylva Ericson (University of Gothenburg, Sweden). 

*To whom correspondence should be addressed. E-mail: leifand@chem.gu.se 









Contents 

5.1.1.  Metadata                                                      50 
5.1.2.  Sampling procedure                                            51 
5.1.3.  Analytical methods                                            51
        5.1.3.1 pH                                                    51
        5.1.3.2 Total alkalinity (TA)                                 52
        5.1.3.3 Dissolved inorganic carbon (DIC)                      53
        5.1.3.4 Certified reference material                          53
5.1.4.  Analytical quality assessment                                 53
        5.1.4.1 pH results: accuracy                                  53
        5.1.4.2 pH sample duplicate results: precision                53
        5.1.4.3 TA results: accuracy                                  54
        5.1.4.4 DIC results: accuracy                                 54
        5.1.4.5 CRM TA results: precision                             54
        5.1.4.6 CRM DIC results: precision                            54
        5.1.4.7 TA sample duplicate results: precision                54
        5.1.4.8 DIC sample duplicate results: precision               54
        5.1.4.9 Data set: station and sample availability             54
                5.1.4.9.1 DIC                                         55
                5.1.4.9.2 TA                                          55
                5.1.4.9.3 pH                                          55
5.1.5.  Internal consistency                                          55
5.1.6.  Certificate of Analysis (CRM)                                 56




5.1.1.  Metadata 

Name of cruise: ARKXXVI/3, PS78, TransArc 

Research vessel: F/S Polarstern 

Time: 5 August (Tromsø) to 7 October 2011 (Bremerhaven) 

Working area: Central Arctic 

Parameters: Total alkalinity (TA), dissolved inorganic carbon (DIC), pH 

Analysts: Adam Ulfsbo and Ylva Ericson (University of Gothenburg, Sweden) 

Methods: Open-cell titration (TA), coulometric titration (DIC), 
         spectrophotometry (pH) 

Data processing: Adam Ulfsbo and Ylva Ericson (University of Gothenburg, 
         Sweden) # samples analyzed: 1254 # stations sampled: 56 

# CRM analyses: 60 bottles 

Name of data file: PS78-2011-CO2-System-Data.csv 

Data file headers: Station, mon/day/yr, hh:mm, Longitude [degrees_east], 
          Latitude [degrees_north], Pres [dbar], Salinity [psu], 
          pot.Temp [°C], TA [mol/kg], DIC [mol/kg], pH-tot-25C 

Preliminary data: The salinity, temperature and pressure data used are 
          preliminary, i.e. as obtained from the CTD without post-cruise 
          calibration. The principal investigator of the oceanographic 
          data is Dr. Ursula Schauer at the Alfred-Wegener-Institut für 
          Polar-und Meeresforschung (AWI), Bremerhaven, Germany. The full 
          CTD dataset is available as: Schauer, Ursula; Rabe, Benjamin; 
          Wisotzki, Andreas (2012): Physical oceanography during 
          POLARSTERN cruise ARK-XXVI/3 (TransArc). Alfred Wegener 
          Institute, Helmholtz Center for Polar and Marine Research, 
          Bremerhaven, doi:10.1594/PANGAEA.774181 




5.1.2  Sampling procedure 

Samples were collected in 250 mL Pyrex borosilicate bottles from a 24-
Niskin bottle CTD-rosette according to Dickson et al. (2007) at 56 
stations, resulting in a total of 1 254 samples analyzed. One bottle was 
sampled for pH and TA, and one for DIC from each depth. All samples were 
analyzed on board within hours (no poisoning, e.g. HgCl). Samples were 
allowed to reach analysis temperature by being placed in a waterbath of 
15°C for ~30 minutes. 



5.1.3  Analytical methods 


5.1.3.1  pH 

pH was determined spectrophotometrically using the sulphonephtalien dye, 
m-cresol purple (mCp), as indicator (Clayton and Byrne, 1993). The method 
is based on the absorption ratio of the indicator at wavelengths 434 and 
578 nm using a 1-cm flow cuvette. Each run consisted of three steps; i) 
rinsing of tubing and cuvette with sample (5 mL) ii) sample blank (25 mL) 
and iii) sample run (20 mL) including indicator (0.5 mL). The sample was 
pumped and mixed using a Kloehn pump. Sample temperature was measured 
after the cuvette. The spectrophotometer (Agilent 8453) was allowed to 
warm up (1 hour) when initialized and Milli-Q water was used as initial 
instrument blank. Determination of indicator pH was performed every other 
day. The indicator solution was prepared on several occasions throughout 
the cruise. Pre-weighed (non-purified) mCp (0.4044 g) was added to 
filtered (0.45 m) seawater (500 mL) from depths below 1500 m. Indicator 
pH was adjusted to a range between 7.80 and 7.93 by addition of HCl 
and/or NaOH. The solutions were stored in airtight plastic bags and kept 
dark. The magnitude of the perturbation of seawater pH caused by the 
addition of indicator solution was calculated and corrected for using the 
method described in Chierici et al. (1999). The final pH values were 
calculated according to Clayton and Byrne (1993), including salinity 
correction. pH data was reported in the total (Hansson) scale at 25.C. 
Table 1 shows the indicator pH over time used for evaluating the final 
pH. 


Table 1: Dye pH per station 

         Station   pH   | Station   pH  | Station    pH   
         ———————  ————— | ———————  ———— | ———————  ——————
          201-7   7.846 |  223-1   7.87 |  246-1   7.9319  
          201-4   7.846 |  224-1   7.87 |  247-1   7.9137  
          202-1   7.837 |  225-1   7.87 |  248-1   7.9137  
          203-4   7.837 |  226-1   7.88 |  249-1   7.9137  
          205-1   7.837 |  226-3   7.88 |  250-2   7.8895  
          205-4   7.837 |  227-2   7.89 |  250-5   7.8895  
          207-2   7.826 |  227-5   7.89 |  251-1   7.8619  
          208-2   7.826 |  228-1   7.85 |  252-1   7.8619  
          209-2   7.836 |  229-1   7.86 |  253-1   7.8619  
          209-4   7.836 |  230-2   7.86 |  254-1   7.8619  
          210-1   7.884 |  230-5   7.86 |  257-1   7.8619  
          211-2   7.878 |  232-1   7.84 |  257-5   7.8619  
          212-2   7.878 |  233-1   7.84 |  258-1   7.8619  
          212-5   7.878 |  234-1   7.92 |  259-1   7.8619  
          214-1   7.886 |  235-2   7.92 |  271-1   7.8922  
          216-1   7.919 |  235-6   7.92 |  272-2   7.8922  
          216-3   7.919 |  239-2   7.80 |  272-3   7.8922  
          218-2   7.882 |  239-5   7.80 |  273-1   7.8922  
          218-7   7.842 |  240-1   7.88 |  274-1   7.8922  
          219-1   7.842 |  241-1   7.88 |  276-1   7.8917  
          220-1   7.842 |  242-1   7.88 |  276-4   7.8917  
          220-4   7.842 |  243-1   7.88 |  277-1   7.8917  
          221-1   7.875 |  244-1   7.90 |  278-1   7.8917  
          222-2   7.859 |  245-2   7.90 |  280-1   7.8917  
          222-5   7.859 |  245-5   7.90 |  280-4   7.8917  


5.1.3.2  Total alkalinity (TA)  

TA was determined by open-cell potentiometric titration with 0.05 M HCl, 
according to Haraldsson et al. (1997) based on Gran evaluation. The 
sample was dispensed into a titration vessel from a thermostated pipette 
of known volume. The titration acid was prepared on board by adding pre-
weighed NaCl (75.972 g) and HCl (1 ampoule 0.1 M for 1000 mL) to a 
volumetric flask (2 L) diluting with Milli-Q water. New electrodes (Orion 
9102AP) were used, which were quality tested in the lab prior to the 
cruise by their Nernst response, but not on board. The system reports TA 
in µmol/L using the nominal acid concentration of 0.05 M. For all samples 
and CRMs, molar concentrations were converted to molinity (µmol/kg-SW) 
using the sample salinity (from the CTD) and the certified salinity, 
respectively, and the temperature measured at the beginning of each 
titration. Sample results were then multiplied by the correction factor 
from the CRM measurements (average value divided by the CRM value). Junk 
samples were measured frequently to keep the instrumentation conditioned. 
No deviant trends were observed regarding acid concentration or 
performance over time. 




5.1.3.3  Dissolved inorganic carbon (DIC) 

DIC was determined using a coulometric titration method (Johnson, 1993) 
with the MIDSOMMA system (Mintrop, 2005). The sample is pumped 
peristaltically into a thermostated pipette, measuring the temperature of 
overflowing water, and dispensed into a stripper where the sample is 
acidified and all inorganic carbon species are converted into aqueous 
CO2. The evolving CO2 is rapidly re-moved from the stripper by a constant 
flowing carrier gas (N2, 5.5) via a condenser to the coulometer (UIC 
model 5012). The titration cell consists of one anodic solution (silver 
electrode) and one cathodic solution (platinum electrode). The CO2 reacts 
in the cathodic cell compartment which becomes more transparent. The 
coulometer subsequently titrates the solution back to its original 
opacity. The required amount of charge is proportional to the amount of 
CO2 reacted and the DIC is readily calculated with known sample volume 
and density. No current-to-frequency calibration was performed pre-or 
post-cruise. No highly accurate determination of pipette volume was 
performed. This was accounted for by the CRM calibration. 

5.1.3.4  Certified reference material 

Certified reference material (CRM) was provided by Dr. Andrew Dickson 
(Scripps Institution of Oceanography, San Diego, USA). A total of 60 CRM 
bottles were analyzed during the cruise with respect to TA and DIC. The 
certificate of analysis for batch 109 used is attached in section 8. 


5.1.4  Analytical quality assessment 

5.1.4.1  pH results: accuracy 

The accuracy of spectrophotometric pH values is difficult to assess, 
since it relies ultimately on the physicochemical characteristics of the 
indicator solution, but is mainly set by the equilibrium constants of the 
indicator. No CRMs were analyzed with respect to pH. Spectrophotometer 
performance was assumed to be sufficient and was not further 
investigated. The system itself was not thermostated and the sample 
temperature might vary until the entire spectra are obtained, 
contributing to uncertain-ties in the accuracy. Sample temperature was 
determined from the resistance of a thermistor. The thermistor was 
changed once during the cruise, with no apparent changes in the 
temperature measurements. Since all samples are affected similarly, a 
more or less constant and small offset should be expected. Internal 
consistency evaluation of pH values with DIC and TA measurements are 
discussed in section 5. 

5.1.4.2  pH sample duplicate results: precision 

A total of 603 duplicates were measured. The overall precision was 0.0004 
(average) or 0.0006 (stdev). Each replicate was measured from the same 
sample bottle and the second measurement could possibly be affected by 
changes in CO2 concentration. However, there was only a small time-lapse 
of 3 minutes between measurements, with only minor change in temperature. 
Triplicates were measured when one of the duplicate measurements seemed 
questionable. 

5.1.4.3  TA results: accuracy 

The accuracy is difficult to assess, since the system is calibrated using 
the CRMs. Assuming that the CRMs are in the certified range (i.e. ± 0.69 
µmol/kg), the accuracy is probably in the same order as the precision. 
Results from CRM vary quite smoothly over time, with slightly higher 
values at the first few stations. Different stations (days) may show an 
offset depending on the CRM measurement (calibration factor) used for 
calibration. The final choice of calibration factors used, is based on 
ambient deep-water profiles, normalized TA and CO2SYS calculations. The 
calibration factors used per station for TA and DIC are shown in Figure 1 
and Figure 2, respectively. 

5.1.4.4  DIC results: accuracy 

Different stations (days) may show an offset depending on the CRM 
measurement (calibration factor) used for calibration. The final choice 
of calibration factors used, is based on ambient deep-water profiles, 
normalized TA and CO2SYS calculations. 

5.1.4.5  CRM TA results: precision 

Precision for TA, defined as the average of the differences between 
duplicate analyses of CRM (Figure 3), was 1.4 mol/kg (1.0 µmol/kg stdev). 
In some cases, replicates were measured when questionable results or 
problems (e.g. incomplete pipette filling, bubbles etc.) were observed. 
Obvious poor measurements were excluded from the data quality assessment 
and the data set. 

5.1.4.6  CRM DIC results: precision 

Precision for DIC, defined as the average of the differences between 
duplicate analyses of CRM (Figure 4), was 2.3 µmol/kg (1.8 µmol/kg 
stdev). 

5.1.4.7  TA sample duplicate results: precision 

Precision for TA sample duplicates (n=77) was in the order of 1.6 mol/kg 
(1.5 µmol/kg stdev). 

5.1.4.8  DIC sample duplicate results: precision 

Precision for DIC sample duplicates (n=117) was in the order of 4.3 
µmol/kg (3.4 µmol/kg stdev). 

5.1.4.9  Data set: station and sample availability 

5.1.4.9.1  DIC 

DIC data are not available for samples 229-1(all), 232-1(all), 230-2(2 
dbar), 251.1(25, 253, 506 dbar). 

5.1.4.9.2  TA 
TA data are not available for samples 211-2(4168 dbar), 229-1(811dbar), 
254-1(1726 dbar). 

5.1.4.9.3  pH 

No remarks. 


5.1.5  Internal consistency 

The carbonate system can be determined from any two of the four master 
parameters pH, TA, DIC and pCO2 (partial pressure of CO2), together with 
known values of relevant stoichiometric acid-base dissociation connstants 
and total concentrations (e.g. Anderson et al., 1999; Zeebe and Wolf-
Gladrow, 2001). The carbonate system was overdetermined (pH, TA, DIC) and 
the internal consistency (or thermodynamic consistency) was assessed by 
comparing measured values to calculated values (from any two of the three 
determined parameters) using the CO2SYS Matlab routine (van Heuven et 
al., 2011). Different sets of the dissociation constants of carbonic acid 
(K1 and K2) were used (Table 2). 


Table 2: Dissociation constants of carbonic acid (K1 and K2) 

     Author                            Temp.  Salinity  pH scale 
     ————————————————————————————————  —————  ————————  ————————
     Mehrbach et al. (1979), refit by   2-35   20-40    Seawater  
       Dickson and Millero (1987)
     Roy et al. (1993)                  0-45    5-45    Total  
     Millero et al. (2006)              0-50    1-50    Seawater  


The average mean difference between measured and calculated values were 
evaluated for pH, TA and DIC. The constants of Millero et al. (2006) 
showed the best overall internal consistency. The average of the 
differences between measured and calculated values are shown in Table 3. 


Table 3: Averages of differences between measured and calculated TA, DIC 
         and pH. 

                     All depths         Depths <200 m       Depths > 200 m  
                ———————————————————  ———————————————————  ———————————————————
Constants        TA     DIC    pH      TA    DIC    pH     TA     DIC    pH  
——————————————  —————  —————  —————  —————  —————  —————  —————  —————  —————
Roy(1993)       21.07  20.14  0.049  18.88  18.08  0.045  21.10  20.17  0.049  
Mehrbachrefit   11.37  10.92  0.027   9.58   9.21  0.024  11.39  10.94  0.027  
Millero (2006)   9.44   9.07  0.023   7.79   7.50  0.019   9.46   9.09  0.023  


Figure 1: Calibration factors used for TA per station. 

Figure 2: Calibration factors used for DIC per station. 

Figure 3: Histogram of absolute differences between duplicate TA analyses 
          of the same CRM. 

Figure 4: Histogram of absolute differences between duplicate DIC 
          analyses of the same CRM. 


                                      University of California, San Diego
CO2   http://andrew.ucsd.edu/co2qc/   Scripps Institution of Oceanography
 QC                                   Marine Physical Laboratory
                                      9500 Gilman Drive
                                      La Jolla, CA 92093-0244 





5.1.6                     Certificate of Analysis

             Reference material for oceanic CO2 measurements
                 Batch 109 (Bottled on December 9, 2010)

This reference material consists of natural sea water sterilized by a 
combination of filtration, ultra-violet radiation and addition of 
mercuric  chloride. 

Analysis Results 

The various procedures used for these analyses are detailed overleaf. 

    Salinity                          33.328 
    Total dissolved inorganic carbon  2026.33  0.56 µmol·kg^(-1) (9; 9) 
    Total alkalinity                  2224.26  0.69 µmol·kg^(-1) (24; 12) 

    Phosphate                         0.40 µmol·kg^(-1) 
    Silicate                          2.80 µmol·kg^(-1) 
    Nitrite                           0.00 µmol·kg^(-1) 
    Nitrate                           2.52 µmol·kg^(-1) 

The cited uncertainties represent the standard deviation. Figures in 
parentheses are the number of analyses made (total number of analyses; 
number of separate bottles analysed). The nutrient levels may have 
changed on storage, their stability has not been examined. CO2 analyses 
were performed over a period of time to confirm that the batch is stable. 

The 95% confidence limits for the certified analyses are thus: 

    Total dissolved inorganic carbon  2026.33  0.43 µmol·kg^(-1) 
    Total alkalinity                  2224.26  0.29 µmol·kg^(-1) 

STORAGE: The bottles should be stored out of direct sunlight, and 
preferably at or below room temperature (25°C). They should not be 
allowed to freeze! 


                                              Andrew G. Dickson
                                               March 17, 2011





Analytical Methods Used 


Salinity 

The salinity was determined by measuring its conductivity relative to 
IAPSO Standard Sea Water using a Guildline Autosal Model 8400 conductive 
salinometer. The procedure is described in an in-house technical manual 
of the Oceanographic Data Facility (ODF), Scripps Institution of 
Oceanography, entitled "Autosal Operating Procedures", dated 10-Dec-1993, 
revised 10-Jan-1994.

Total dissolved inorganic carbon 

The total dissolved inorganic carbon was assayed in Dr. C.D. Keeling's 
laboratory at the Scripps Institution of Oceanography by the vacuum 
extraction/ manometric procedure. The weighed sample is acidified with 
phosphoric acid; the CO2 evolved is then extracted under vacuum and 
condensed in a trap cooled by liquid nitrogen. The water and CO2 are 
separated from one another by sublimation and the CO2 is transferred into 
an electronic constant-volume manometer [ECM]. There its pressure, volume 
and temperature are measured and the amount of CO2 separated is computed 
from the virial equation of state. 

Alkalinity 

The total alkalinity was assayed by a two-stage, potentiometric, open-
cell titration using coulometrically analyzed hydrochloric acid. A 
weighed sample of reference material is acidified to a pH between 3.5 and 
4.0 with an aliquot of titrant. The solution is stirred for a period of 
time to allow the evolved CO2 to escape. The titration is then continued 
to a pH of about 3.0 and the equivalence point evaluated from titration 
points in the pH region 3.0-3.5 using a non-linear least squares 
procedure that corrects for the reactions with sulfate and fluoride ions 
(Dickson, A.G., Afghan, J.D. & Anderson, G.C., 2003. Reference materials 
for oceanic CO2 analysis: A method for the certification of total 
alkalinity. Marine Chemistry 80, 185Р197). 

Nutrients 

Nutrient levels were determined using a modified 4-channel autoanalyzer. 
The procedures are similar to those described in Gordon, L.I., J.C. 
Jennings, A.A. Ross, J.M. Krest (1993) "A Suggested Protocol for 
Continuous Flow Automated Analysis of Sea Water Nutrients (Phosphate, 
Nitrate, Nitrite, and Silicic Acid) in the WOCE Hydrographic Program and 
the Joint Global Ocean Fluxes Study", WOCE Operations Manual, WHP Office 
Report WHPO 91-1 (rev. Nov. 1994) 



References 


Anderson, L.G., Turner, D.R., Wedborg, M., Dyrssen,D., 1999. 
    Thermodynamic calculations of the CO2 system in seawater, In: 
    Kremling, K., Ehrhards, M. (Eds.), Methods of Seawater Analysis, 
    third edition. VCH, Weinheim, Germany, pp. 141-148. 

Chierici, M., Fransson, A., Anderson, L.G., 1999. Influence of m-cresol 
    purple indicator additions on the pH of seawater samples: correction 
    factors evaluated from a chemical speciation model. Marine Chemistry, 
    65, 281-290. 

Clayton, T.D., Byrne, R.H., 1993. Spectrophotometric seawater pH 
    measurements: total hydrogen ion concentration scale calibration of 
    m-cresol purple at-sea results. Deep-Sea Research I, 40(10), 
    2115.2129. 

Dickson, A.G., Sabine, C.L. and Christian, J.R. (Eds.) 2007. Guide to 
    best practices for ocean CO2 measurements. PICES Special Publication 
    3, 191 pp. 

Haraldsson, C., Anderson, L.G., Hassellv, M., Hulth, S., 1997. Rapid, 
    high-precision potentiometric titration of alkalinity in ocean and 
    sediment pore waters. Deep-Sea Research, 44, 2031-2044.y 

Johnson, K.M., Wills, K.D., Butler, D.B., Johnson, W.K., Wong, C.S., 
    1993. Coulometric total carbon dioxide analysis for marine studies: 
    maximizing the performance of an automated gas extraction system and 
    coulometric detector. Marine Chemistry, 44, 167-187. 

Mintrop, L., 2005. MIDSOMMA manual version 2.0, Marine Analytics and Data 
    (MARIANDA), Kiel, Germany. 

van Heuven, S., D. Pierrot, J.W.B. Rae, E. Lewis, and D.W.R. Wallace. 
    2011. MATLAB Program Developed for CO2 System Calculations. 
    ORNL/CDIAC-105b. Carbon Dioxide Information Analysis Center, Oak 
    Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, 
    Tennessee. doi:10.3334/CDIAC/otg.CO2SYS_MATLAB_v1.1 

Zeebe, R.R., Wolf-Gladrow, D., 2001. CO2 in Seawater: Equilibrium, 
    Kinetics, Isotopes. Elsevier Oceanography Series, 65. 





5.2  Radium and Thorium isotopes 

     Michiel Rutgers van der Loeff, Daniel Scholz    Alfred-Wegener Institut 
     Alex Charkin                                    POI-FEBRAS, Vladivostok 


Objectives 

The particle export from surface water can be determined with the short- 
lived isotope 234Th (half-life 24 days). During ARK-XXII/2 in 2007 we 
have found that 234Th-based export rates of carbon were very low in the 
central Arctic (Cai et al., 2010), but there were indications of enhanced 
particle fluxes in the area of the Lomonosov Ridge. During the present 
expedition we wanted to repeat these measurements in coordination with 
the more extensive biological sampling of the PEBCAO program and as back-
ground for the data to be collected with the sediment traps deployed in 
the Gakkel Ridge area. 

Four radium isotopes are supplied to the ocean by contact with the 
continent or (deep-sea)-sediments: 223Ra, (half-life 11.4 d); 224Ra (3.7 
d), 226Ra (1620 y) and 228Ra (5.8 y). The distribution of these isotopes 
in seawater has been shown to be most helpful to evaluate shelf-basin 
exchange and water residence times. 228Ra is released by sediments and 
accumulates to high activities over the Arctic shelves. When these waters 
are transported in the fresh surface water layer over the central Arctic 
Ocean towards Fram Strait, the signal decays with the half-life of 5.8 y. 
The isotope is therefore used to trace this transport of shelf-influenced 
waters in the Trans Polar Drift. During this transport, the granddaughter 
228Th, which is efficiently removed on the shelves, grows towards 
equilibrium. The distribution of the 228Th/228Ra ratio is therefore 
determined by a competition between ingrowth, which depends on time 
(228Th half-life 1.9 yr) and removal, which depends on particle flux. 

This shows why, apart from the interest for the carbon cycle, the 
distribution of scavenging rates is also important for the interpretation 
of the behaviour of other trace elements and isotopes like 228Th. We will 
derive this distribution in first line from the distribution of the total 
234Th/238U ratio in surface waters. But further information has been 
obtained from the distribution of suspended material from direct 
filtrations and from transmissometry. These scavenging rates will then be 
used to interpret the 228Th/228Ra data and determine to what extent these 
isotope data can be used as time marker for shelf waters. 

The short-lived radium isotopes 224Ra and 223Ra are used extensively for 
the study of submarine groundwater discharge. Because we were not allowed 
to work in the Russian EEZ, it was unlikely that we would see any excess 
activities of these isotopes due to their release from the coast or shelf 
sediments. We have therefore primarily used them as proxies for their 
longer-lived parents 228Th and 227Ac. 

Work at sea 

We have taken samples for 234Th analysis in coordination with the 
sampling for plankton, POC, chlorophyll by the biologists. We have 
determined the 234Th profiles in the upper 200 m of the water column on a 
total of 17 stations. The total 234Th samples have been counted onboard 
using RISO beta counters mounted in the geochemistry container. Final 
234Th activities can only be given after the yields have been determined 
from the recovery of a 230Th spike added to every sample. These yield 
measurements will be made after decay of the 234Th (a minimum of 6 
months) with mass spectrometry in the home laboratory. The activity of 
the parent nuclide, 238U, is usually obtained from salinity. We have 
collected a series of samples to check the applicability of the 
U/salinity relationship established in other oceans through mass 
spectrometry. From the 234Th/238U ratio we will determine the scavenging 
rates in the surface water. This will give us an estimate of POC export, 
which we can compare with the results of the 2007 expedition and with 
fluxes we hope to measure with the sediment traps deployed in the Gakkel 
Ridge area. In order to convert thorium to POC fluxes, we will determine 
the POC/234Th ratio on particulate matter that we obtained by filtration 
of 8-L water samples collected at 200 m depth over precombusted QMA 
filters. The relationship between the POC/234Th ratio determined on bulk 
suspended matter and size-fractionated material was determined on the 
previous expedition by Pinghe Cai. 

Because of the special interest during this expedition in processes in 
the water column immediately under the ice, we have, in addition to the 
profiles measured in CTD casts from the ship, also determined the 234Th 
profiles in the upper 16 m of the water column under the ice. For this 
purpose, samples were collected during ice stations 209, 212, 218, 222, 
227, 230, 235 by suction through a plastic tube into 4-L plastic 
containers. On later ice stations 245 and 250, low air temperatures 98 
caused freezing of the water in the tubing, and samples were collected 
with the 2-L water samplers used by the sea-ice biogeochemistry group 
(Dieckmann). 

For radium isotopes, large volume surface water samples were collected 
into 300.L tanks. Each sample is filtered through a 0.8µ supor filter and 
then passed at a flow rate of < 1 L/min using a peristaltic pump through 
MnO2-impregnated acrylic fiber to scavenge radium isotopes. Fibers are 
partially dried using compressed air, and short-lived 223Ra and 224Ra 
measured at sea using RaDeCC delayed coincidence alpha detectors. The 
longer-lived isotopes will be measured on the fibers by leaching, 
coprecipitation of Radium on BaSO4 and gamma counting 228Ra and 226Ra in 
the shore-based lab. During the GEOTRACES Radium intercalibration it has 
been observed that ship's seawater intake systems may contain 228Th, 
which can serve as a source for 224Ra. After the first samples collected 
in the fish lab from the ship's seawater inlet had given high count 
rates, we checked this problem by comparing (stations 201-212) the 
activities obtained from samples collected much closer to the intake 
(basin in the front container storage room/ Ladeluke vorn) and with 
samples collected through a new 50-m PVC tube with a pump (Grundfoss 
Brunnenpumpe or GFPump) deployed overboard the ship, usually during CTD 
casts. Indeed, the samples collected with the pump showed clearly the 
lowest activities and we decided to use that sampling exclusively (from 
station 217 onward). Surface water samples were collected at a total of 
41 stations. 

Preliminary results 

The 224Ra data measured immediately on board ship (Fig. 5.2) are thought 
to represent the total activity of the mother nuclide 228Th. The activity 
of particulate 228Th (collected on filters) and of its parent 228Ra has 
to be measured later in the home laboratory. The geographical 
distribution of 224Ra shows enhanced activities upon crossing the Trans 
Polar Drift in the vicinity of the Lomonosov Ridge. 


Fig. 5.2. Preliminary results of the distribution of 224Ra (dpm/m3) in 
          surface waters during ARK-XXVI/3 


References 

Cai, P., Rutgers v.d. Loeff, M. M., Stimac, I., Nhig, E.-M., Lepore, K., 
    and Moran, S. B., 2010. Low export flux of particulate organic carbon 
    in the central Arctic Ocean as revealed by 234Th:238U disequilibrium. 
    Journal of Geophysical Research -Oceans 115, C10037, 
    doi:10.1029/2009JC005595. 


5.3  Tracing terrestrial carbon across the Arctic shelf and slope 

     Alexander Charkin                      POI-FEBRAS Vladivostok 
     Michiel Rutgers van der Loeff          Alfred-Wegener-Institut 


Objectives 

The Arctic Ocean receives >10% of the global river sediment discharge 
while only hosting 1% of the total ocean volume. Furthermore, the 
Eurasian part of the Arctic Shelf is the world's largest continental shelf 
sea system strongly influenced by high input of terrigenous material 
derived from surrounding land masses and supplied by large river systems. 
The productivity is relatively low in the Arctic Ocean in comparison with 
other world regions, because of the permanent ice cover. Only along ice 
edges and in some areas that are ice free during summer months, sometimes 
higher productivities occur. Therefore, the sediments in the Arctic Ocean 
mainly show a terrigenous composition, and biogenic particles only occur 
in minor amounts. Our study focuses on the investigations of the major, 
trace, and rare earth elements (REE) geochemistry, organic carbon (OC), 
isotopic (δ13C) composition and carbon/nitrogen (C/N) ratios of the 
sedimentary material for the identification of the terrestrial signal 
across the Arctic Shelf and slope. 

Work at sea 

Water samples for suspended particular matter (SPM) and particulate 
organic carbon (POC) filtration have been collected from the rosette 
system. The SPM for geochemistry of rare earth elements was obtained by 
filtration through membrane filters with pore diameter of 0.47 m. The POC 
for organic carbon concentration, isotopic (δ13C) composition and 
carbon/nitrogen (C/N) ratios was obtained by filtration through 
borosilicate glass fiber filters (GF/F; Whatman Inc. with approximate 
pore diameters of 0.7 m). The filtered water volume for SPM and POC was 
up to 4L, depending on sediment load. Additionally, 20 surface sediment 
samples (upper 2 cm) have been collected from cores taken with the 
Multicorer. 

Expected results 

In total, we obtained 220 samples of SPM, POC and 20 samples of surface 
sediments for the analysis of the major, trace, and rare earth elements 
(REE) geochemistry, organic carbon (OC) content, isotopic (δ13C) 
composition. Elementary (C,N) and isotopic (δ13C) composition of SPM and 
bottom sediments will be determined after the cruise by Carlo Erba 
elemental analyzers and a Finnigan MAT Delta Plus mass spectrometer, 
respectively, at the International Arctic Research Center, University of 
Alaska, Fairbanks (USA) or with similar instruments at Stockholm 
University (Sweden). REE elements will be analyzed in the Institute of 
chemistry FEB RAS, Vladivostok (Russia). 


5.4  7Be as tracer for determining atmospheric deposition of trace 
     elements 

     Ben Galfond                            Rosenstiel School of Marine 
                                            and Atmospheric Sciences 
                                            (RSMAS) Miami, USA 
     Not on board: David Kadko, William Landing 


Objectives 

The atmospheric input of numerous chemical species into the global ocean 
equals or exceeds that from river sources and thus constitutes an 
important budgetary component for these elements. The atmospheric input 
of trace elements plays a key role in ocean biogeochemical processes as 
well, unfortunately the assessment of this input is difficult as 
measurements of deposition rates to the ocean -particularly the Arctic- 
are rare and susceptible to problems of temporal and spatial variability. 
Given the dearth of direct measurements, the ocean community has relied 
on atmospheric transport and deposition models that are unconstrained as 
to the amounts of rainfall delivered to the ocean and the parameteriza-
tion of aerosol removal processes. If such parameters could be accurately 
assessed, then the chemical concentration of aerosols could be 
transformed to actual estimates of flux. 

Indirect methods, such as the use of natural radionuclides delivered to 
the ocean from the atmosphere, are often used to estimate atmospheric 
inputs. During this expedition we have used measurements of 7Be in the 
surface waters, snow/ice cover and in the lower atmosphere, coupled with 
trace element measurements in aerosols, to provide estimates of the 
atmospheric input of relevant trace elements into the Arctic Ocean. The 
ability to readily derive 7Be flux from the ocean/ice inventory provides 
the means to link the chemical concentration data of precipitation and 
aerosols to flux. We have also addressed the partitioning of 7Be and 
trace elements between the ice/snow and the open water. This method could 
ultimately be applied to seasonal study in the Arctic as the partitioning 
would be expected to vary throughout the year. This in turn would give 
insight into how trace element deposition will change as sea ice 
conditions in the Arctic evolve in the future. 

7Be is a cosmic ray produced radioisotope that becomes associated with 
particles in the troposphere and subsequently deposited to the surface 
ocean. Because of its relatively short half-life (53.3 days) it is 
reasonable to equate the inventory of 7Be decay in the upper ocean and 
snow, to the flux of 7Be from the atmosphere. This provides a key linkage 
between the atmospheric concentration of chemical species and their 
deposition to the ocean. Such species include many of interest to the 
GEOTRACES program such as Hg, Al, Mn, Fe, Cu, Zn, and Cd. 

Work at sea 

At open water stations, mixed layer seawater from the ship's internal 
system was collected in 600 L tanks, which was then filtered through iron 
impregnated acrylic fibers, which bind the 7Be, allowing for later 
measurements on land. For ice stations, the mixed layer samples where 
instead filtered in-situ on the ice floe.  This presents us with a sample 
that is unperturbed by mixing form the ship.  A mobile CTD cast performed 
by the group of Dieckmann allowed us to target the center of the mixed 
layer at every station. Samples of snow, ice cores, and meltpond water 
were also collected and then precipitated with FeCl3 for transport back 
to land. A pump was used to fill 1000 L tanks on the deck of the ship 
from a depth of 40 m, allowing us assess the complete water column 7Be 
inventory. Aerosols were collected on paper filters for analysis of 7Be 
and trace metal content. Quartz fiber filters allow for the study of both 
7Be and mercury as well. 


5.5  Net community productivity using dissolved O2/Ar/222Rn 

     Nicolas Cassar                         Duke University 
     Michiel Rutgers van der Loeff,         Alfred-Wegener-Institut 
     Daniel Scholz  


Objectives 

The objective of this project is to estimate net community productivity 
in the Arctic Ocean using dissolved O2/Ar measurements, and constrain the 
biogeochemical controls on carbon fluxes. Oxygen in the mixed layer is 
influenced by biology, and by physical processes such as bubble 
injection, temperature and pressure changes. Because argon (Ar) has 
similar solubility properties as oxygen, the oxygen derived from physical 
processes can be estimated from the argon concentration relative to its 
saturation ([Ar]sat). The oxygen derived from biology is equal to the 
total oxygen minus the oxygen derived from physical processes. 

222Rn was used as an independent measure of air-sea exchange. 222Rn is 
produced in the water column from 226Ra dissolved in seawater. Exchange 
with the atmosphere creates a depletion in surface waters that can be 
used as quantification of air-sea exchange. This will give us an 
additional tool to convert the oxygen over- or under-saturation derived 
from O2/Ar ratios into oxygen fluxes and thus into net community 
productivity (NCP). 


5.5.1  Net community production using O2/Ar ratios in surface waters. 

       Nicolas Cassar                       Duke University 

Work at sea 

Biological oxygen supersaturation was measured continuously by 
Equilibrator Inlet Mass Spectrometry (EIMS, Fig. 5.3), a method 
previously described (Cassar et al., 2009). Briefly, seawater from the 
ship's underway system was pumped through a gas equilibrator, the 
headspace of which was connected to a quadrupole mass spectrometer for 
continuous elemental O2/Ar ratio measurements. The ion current ratio was 
calibrated by periodically sampling ambient air. From the O2/Ar 
supersaturation, a gas exchange rate, and the oxygen concentration at 
saturation, the net biological oxygen flux across the ocean surface will 
be estimated. 

The large seawater reservoir (A) sits in a sink. After going through an 
inline coarse filter (500 .m pore size), seawater flows into the inner 
reservoir (B) at a rate of 3-5 L min-1 (large arrow). Most of the water 
running into B overflows into A, which is used as a water bath 
thermostatted to the temperature of ambient seawater. A small fraction 
(100 mL min-1) of the high flow rate is pulled with a gear pump through a 
filter sleeve (C), with 100 and 5 .m pore size on the outside and inside, 
respectively. From the gear pump, the seawater flows through the 
equilibrator (D). The equilibrator sits in reservoir A to keep its 
temperature identical to that of the incoming seawater. A capillary, 
attached to the headspace of the equilibrator, leads to a multiport Valco 
valve. This valve alternates between admitting gas from the equilibrator 
and ambient air to the quadrupole mass spectrometer. An optode (not 
shown) in container B measures total oxygen saturation. Also not shown is 
a water flow meter located downstream of the equilibrator and 
thermocouples Spectrometry throughout the system (from Cassar et al. 
2009) 

A transmissometer was also installed on the ship’s underway seawater 
system in order to estimate semi-quantitatively the POC concentration 
(Gardner et al. 1993). The transmission signal will be calibrated with 
POC measurements performed every few hours by the group of A. Boetius. 

Preliminary results 

Results will only be available after calibration of the ion current ratio 
32/40 (O2/ Ar) signal and transmissometer data. Our preliminary 
observations suggest large biological activity in the marginal sea ice 
zone and potentially in regions above ridges. 


5.5.2  Gas exchange rate using 222Rn depletion in surface waters 

       Michiel Rutgers van der Loeff,       Alfred-Wegener-Institut 
       Daniel Scholz 

Objectives 

In order to derive gas exchange rates from the measurements of oxygen 
saturation, we need the piston velocity. In open water this is usually 
taken from empirical relationships between wind stress and piston 
velocity. Few data exist for ice-covered seas. Originally it has been 
widely assumed that ice cover would completely prevent gas exchange, but 
Fanning and Torres (1991), using the depletion of 222Rn in surface waters 
as tracer, reported significant gas exchange in the ice-covered Barents 
Sea, comparable to 70% of the open ocean value. Much lower exchange rates 
were found recently by Loose and Schlosser (2010). It was our aim to use 
the 222Rn technique to derive gas exchange rates in the range from fully 
ice-covered to open water conditions. 

Work at sea 

We have determined the 222Rn activity profile in the upper 50 m of the 
water column at 18 stations using the method of Mathieu et al. (1988). At 
each sampling depth a 30-L sample was collected with the Multiple Water 
Sampler and 27 liter was allowed to flow into evacuated PVC containers. 
After stripping the samples for Radon, the samples were passed over a 
MnO2-coated fibre to collect the Radium parent. As standard sampling 
depths we used 2, 5, 10, 20, 30, 50 m. Due to the strong stratification 
with a stable halocline usually at 20-30 m depth, we did not expect any 
deeper mixing on the time scale covered by 222Rn (3.8 days half-life). 
Any gas exchange with the atmosphere should be seen in a depletion of 
222Rn in the surface water relative to its parent 226Ra. 

In an attempt to see possible gas exchange on a smaller scale in the 
water just below the ice, we have collected 5L water samples from just 
below the ice. A plastic tube was lowered through a hole drilled in the 
ice and samples were collected by connecting the tube (after rinsing with 
a hand-operated vacuum pump) to 5.8L evacuated glass jars. With the same 
Radon stripping technique Radon was determined in these samples, but 
because of the lower volume the relative error in the data is 5 times 
larger. 

Preliminary results 

Exact data on 222Rn depletion can only be given after the determination 
of the activity of the parent 226Ra which has to follow in the home 
laboratory. We know that 226Ra is correlated with salinity and silicate 
content, and we also know that 226Ra is higher in water of Pacific than 
of Atlantic origin. Indeed, the 222Rn activities in the water below the 
surface mixed layer tended to be highest in the stations in the middle of 
the expedition (approximately stations 218-239) where we know from 
nutrient data (biogeochemistry group) that the water was largely of 
Pacific origin. But as we do not expect large gradients in 226Ra over the 
upper 50 m, the 222Rn profiles already give an indication of the 
existence of a 222Rn depletion in surface waters. 

Only the last four stations (273, 276, 280, 285) were in fully open 
water. Here we observed a clear depletion of 222Rn in the upper three 
horizons (2, 5, and 10m, Fig. 5.4).  This is in good agreement with the 
many studies where 222Rn has been used to quantify gas exchange rates. 
However, in the stations where we had full ice cover (212-245) we did not 
observe a significant difference between the upper 10 m and the deeper 
samples, which brings us to the preliminary conclusion that the gas 
exchange rate is here severely limited, at any rate stronger than 
suggested by the results or Fanning and Torres. 

The sampling directly under the ice was successful only on the ice 
stations 212, 218, 222, 227, 230 and 235. During later ice stations the 
low air temperatures caused immediate freezing of the water in the 
tubings and prevented proper sampling. The results of the under-ice 
sampling with 5-L jars have inherently larger errors than the results 
obtained with 30-L samples from the ship (Fig. 5.4). The lack of a 
significant difference between the two sampling strategies implies that 
we have no indication of even a thin layer under the ice with enhanced 
gas exchange with the atmosphere. 

Fig. 5.4 Left: Average profiles of 222Rn activity (with standard error) 
               in the upper 50 m, distinguishing stations with full ice 
               cover (red, n=9) and with fully open water (blue, n=4), 
               normalized to the respective average activities in the 20-
               50 m layer. 
         Right: average profiles of 222Rn activity (with standard error) 
               at ice stations as determined in 27-L samples collected 
               from the ship (red, n=9)) and in 5-L samples collected 
               through a hole in the ice (blue, n=6). 


References 

Cassar, N., Barnett, B.A., Bender, M.L., Kaiser, J., Hamme, R.C., 
    Tilbrook, B., 2009. Continuous High-Frequency Dissolved O2/Ar 
    Measurements by Equilibrator Inlet Mass Spectrometry. Anal. Chem. 81, 
    1855-1864. 

Fanning, K. A. and Torres, L. M., 1991. 222Rn and 226Ra: indicators of 
    sea-ice effects on air-sea gas exchange. In: E., S., E., H. C. C., 
    and A., O. N. (Eds.), Pp. 51-58 in Proceedings of the Pro Mare 
    Symposium on Polar Marine Ecology, Trondheim. 12-16 May 1990. Polar 
    Research 10(1). 

Gardner, W. D., Walsh, I. D., Richardson, M. J. 1993. Biophysical forcing 
    of particle production and distribution during a spring bloom in the 
    North Atlantic. Deep-Sea Research II. 40, 171-195. 

Loose, B. and Schlosser, P., 2010. Sea ice and its effect on CO2 flux 
    between the atmosphere and the Southern Ocean interior. Journal of 
    Geophysical Research 116, C11019, doi:10.1029/2010JC006509. 

Mathieu, G. G., Biscaye, P. E., Lupton, R. A., and Hammond, D. E., 1988. 
    System for measurement of 222Rn at low levels in natural waters. 
    Health Physics 55, 989-992. 



5.6  Mercury cycling in the Arctic  

     Ben Galfond                            RSMAS, Miami  
     Michiel Rutgers van der Loeff          Alfred-Wegener-Institut  
     Samples taken for: Lars-Eric Heimbrger (Geosciences Environment 
     Toulouse at Midi-Pyrenees Observatory OMP, Toulouse) 


Objectives Major objective of this program was exploring the role of the 
Arctic Ocean in the global mercury cycle.  Key questions are: 

1. What controls methyl mercury (MeHg) trends and variability in the 
   Arctic Ocean? 

2. Is the Arctic a sink for atmospheric Hg contamination? 

3. What is the environmental response of the MeHg cycle to climate change 
   and increasing anthropogenic emissions? 

4. What are the causes for the alarming rise of Hg levels in Arctic 
   biota? 


Work at sea 

As the PI was not able to participate in the expedition, this project was 
severely limited. Samples for the analysis of MeHg were collected from 
the CTD/Rosette system at stations 218, 245, 273, 280 by Ben Galfond. 
Expected results Alarming rise in Hg levels of Arctic marine biota has 
been attributed to increased anthropogenic Hg emissions. However, the Hg 
species that accumulates along the trophic chain is MeHg. MeHg is 
produced in the oceanic water column during the remineralization of 
organic matter. This process seems to be independent from atmospheric Hg 
deposition. The basis of the food web structure determines the amount of 
MeHg that is produced in situ. We measured for the first time MeHg in the 
central Arctic Ocean. This is critical to predict the impact of ongoing 
global warming on the Arctic Hg cycles. Total and MeHg have been 
determined on 4 stations. 



5.7  Distribution of 236U and of Cs isotopes 

     Michiel Rutgers van der Loeff          Alfred-Wegener-Institut 


Objectives 

236Uranium is an anthropogenic radionuclide introduced in the environment 
by nuclear test explosions and by reprocessing of nuclear wastes. The 
invasion of this transient tracer into the World Ocean has recently 
become an issue of much interest. After the nuclear accident in the power 
plants of Fukushima, March 2011, it is important to know how the 
radioactivity released spreads over the globe. A nuclide that is readily 
detected is 134Caesium (2 y half-life). 

Work at sea 

We have collected samples for analysis of 236U by two teams. 1-L surface 
samples were collected at 15 stations for the group of Gideon Henderson, 
University of Oxford to be analysed by mass spectrometry. Full depth 
profiles of 15-20L samples were collected in the deep basins (stations 
204 and 218 in the Eurasian Basin, stations 226 and 245 in the Makarov 
Basin, station 235 in the Canada Basin). These samples will be analysed 
by Marcus Christl (ETH, Zich) with Accelerator Mass Spectrometry. For the 
analysis of Cs isotopes we have collected 21 100-L samples (14 from the 
ship’s seawater inlet, 7 from meltponds on ice stations). These samples 
will be analysed for 134Cs and 137Cs by gamma spectrometry in the home 
laboratory. 

Work at sea 

The distribution of 236U will be used to investigate what this novel 
tracer can tell us about the transport of Atlantic water and to quantify 
ventilation rates of deep waters in the Arctic. The distribution of 134Cs 
will allow us to judge whether significant amounts of nuclides released 
by the Fukushima accident had reached the Arctic half a year after the 
event. 












6.  BIOGEOCHEMISTRY  

    Gerhard Dieckmann, Ellen Damm,          Alfred-Wegener-Institut
    Elisabeth Helmke, Kai-Uwe Ludwichowski, 
    Claudia Burau, Laura Wischnewski, 
    Eva Kirschenmann    


Objectives  

The aim of the biogeochemistry group was essentially to characterise the 
biogeochemical properties and processes in and below the sea ice. Sea ice 
is a structuring component of the Arctic Oceans and plays a pivotal role 
in the biogeochemical cycles of Arctic marine ecosystems. The sea-ice 
cover greatly affects energy and material fluxes between the ocean and 
the atmosphere, and provides a habitat for diverse microbial assemblages, 
which in terms of biomass are generally dominated by algae. 

The biogeochemistry of Arctic sea ice has been poorly documented to date. 
Our aim was to obtain information on biogeochemical processes in sea ice 
during its seasonal transition. Our specific objectives were: i) to make 
an extensive characterization of the biogeochemical environment 
experienced by sea ice communities, ii) to investigate microbiological 
processes in relation with the physical-chemical environment, iii) to 
investigate the methane cycle in sea ice and sea ice/water interface, iv) 
to investigate the occurrence and abundance of cryogenic carbonate 
minerals (CaCO3) in sea ice as part of its internal carbon cycle, v) to 
investigate the fate of land derived organic matter in sea ice, and vi) 
to study the hydrography at the sea ice/water interface. 

Work at sea 

Extensive sampling took place during 15 ice stations. Samples were taken 
from: i) sectioned ice cores in collaboration with the sea ice physics 
group for bulk ice measurements, ii) sackholes drilled in sea ice, and 
iii) depth profiles of seawater taken with a CTD from the ice to avoid 
influences from the ship. Where possible, water samples were taken 
directly under the ice at high resolution (e.g. 0.1 m, 0.5 m, 1 m, 2 m). 
Further samples were generated by a number of experiments designed to 
investigate the contribution of the major sea ice biogeochemical 
parameter, i.e. methane. 

The collected samples provided data of salinity, temperature, pH and 
total alkalinity, chlorophyll, and coloured dissolved organic matter (C-
DOM), major dissolved inorganic nutrients, nitrate plus nitrite ([NOx]), 
phosphate ([P]), and silicate ([Si]), dissolved organic carbon (DOC). The 
determination of other parameters will be conducted in the home 
laboratories. The sectioned cores were returned to the laboratory where 
they were allowed to melt at +4C. Calcium carbonate was analysed from all 
cores. 

Sea-ice brine was collected from sackholes and the lower-most centimetres 
of the sea-ice floe were sampled by means of ice coring. These samples 
were used for the determination of the same parameters as the ice cores. 
Kemmerer water samplers were deployed through the core holes for water 
samples for analyses corresponding to the ice core and brine analyses. 

A total of 180 samples were taken for the determination of dissolved 
organic matter (DOM) at representative stations. Bulk determinations of 
dissolved organic carbon (DOC) and nitrogen (DON) will be carried out 
after the cruise in the home lab. 

DOM samples were taken for bulk determinations (DOC/DON) and extracted 
from seawater using PPL sorbent (enrichment of DOM by solid phase 
extraction). DOM sampling was decided after consulting the fluorescence 
profiles on the CTD. Different water masses were sampled (e.g. 
fluorescence max. and 10 m above sea bottom) and chemically characterized 
after the enrichment using ultrahigh resolution mass spectrometry (FT-
ICR-MS) in the home lab. Additionally, all samples were extracted on 
board using solid phase extraction with PPL sorbent. This will facilitate 
the analysis of detailed chemical DOM characteristics by ultrahigh 
resolution mass spectrometry also later at the home lab. 

Sea-ice brine, Kemmerer bottle samples and water samples taken with the 
rosette sampler at different depths were analysed for nitrate, nitrite, 
ammonium, phosphate and silicate content immediately on board with an 
Autoanalyzer-System according to standard methods. 

Methane and DMS was immediately measured on board ship, using gas 
chromatographs equipped with a flame ionization detector (FID) and a 
pulsed flame photometric detector (PFPD), respectively. Furthermore, DMSP 
particular and dissolved was analysed in seawater, ice and sediments. Gas 
samples were stored for analyses of the .13CCH4 values in the home 
laboratory. In addition to the sea ice sampling, different water masses 
were sampled by CTD rosette from the ship at discrete depths throughout 
the water column at 60 stations. Samples were treated the same as the sea 
ice samples. 

The bacterial communities of sea ice, meltponds and under ice water (0.5 
m) were investigated at all 15 sea-ice stations by determining bacterial 
biomass, total numbers, bacterial diversity and bacterial community 
structure as well as secondary production. 

Bacterial secondary production was determined on board under in-situ like 
temperature conditions. Although the results between the different 
stations varied considerably at least clear differences between sea ice 
and meltpond communities of the Eurasian and Pacific part of the Arctic 
Ocean became obvious. Cultural work was done with selected samples only. 
These cultures will be the basis for the isolation of representative sea-
ice and melt-pond strains and will help to understand survival and 
reproduction capabilities of the different types and will give new ideas 
concerning adaptation strategies. 

Final working steps will be done in the home laboratory. After completion 
of the whole set of analyses, like filtration, preservation, washing and 
freezing, we will be able to compare the new data set from predominantly 
first-year ice with material from 1997, 1999, and 2001 from predominantly 
multiyear sea ice and Antarctic sea-ice communities. 

Preliminary results 

Fig. 6.1 shows an example of a typical profile of salinity and 
temperature obtained with the SEACAT CTD deployed through an ice core 
hole at station 218. Shown are the down and up casts. The dramatic 
temperature rise and low salinities in the top meter of the water column 
at the sea ice water interface is clearly indicative of melting, whereas 
the top 20 meters of the water column below the ice appears to be well-
mixed. This is followed by a clear rise in temperature and increase in 
salinity below a depth of 20 to 25 meters, which is again followed by a 
drop in temperature and decrease in salinity. 


Fig. 6.1: A scrutiny of the data as well as comparison with the ship’s 
          CTD data is essential before the hydrographic features under 
          the sea ice can be clearly interpreted. 




7.  MARINE BIOLOGY 

7.1  Biology of sea-ice and related ecosystems 

     Ilka Peeken                            AWI/MARUM 
     Christophe Boissard                    LSCE/CNRS 
     Mar Fernandez Mendez                   AWI/MPI 
     Kristin Hnselmann                      AWI/University Hamburg 


Objectives 

The decrease in summer sea-ice extent and in the concentration of 
multiyear ice (MYI) is expected to have major implications for the sea-
ice biota by affecting its biomass, primary productivity and 
biodiversity. Due to the high spatial heterogeneity of sea-ice biota, 
current estimates of total biomass still need to be improved by using 
remotely operated vehicles equipped with biomass sensors. 

The loss of sea ice might be favourable for the phytoplankton primary 
production by increasing the length of the growing season. However, 
nutrient availability is considered to be the limiting factor controlling 
primary production in the Arctic Ocean. Nutrient depletion together with 
warming has been shown to lead to an increase in especially small 
phytoplankton, resulting in relatively poor food quality at higher 
trophic levels. Additionally, the replacement of MYI by first year ice 
(FYI) will further increase the occurrence of melt ponds, an ecosystem 
that has been largely overlooked in previous investigations. 

Phytoplankton and sea-ice algae have an influence on the production of 
organic compounds some of which can have a significant influence on the 
photochemistry of the atmosphere, particularly unsaturated hydrocarbons 
(such as isoprene:2.methyl-1,3 butadiene, or light alkenes) and carbon 
monoxide (CO) which have a strong impact on the OH radical and ozone 
budget as well as on the formation of organic aerosols playing an 
important role on cloud-condensation nuclei (CCN) number and thus on 
cloud lifetime and properties. 

Our questions and objectives for this cruise were: 

• What are the relative contributions to primary productivity (PP) of the 
  different phototrophic communities in the central Arctic Ocean? 

• Will higher light intensities due to thinner ice boost PP in the ice in 
  summer or will it be limited by nutrient supply?  What are the 
  contributions of pico- and nanoplankton in the various habitats? 

• How are biodiversity and carbon pool changing in the different sea ice 
  types and melt ponds? 

• Establish optical measurements for biomass estimation in sea ice for 
  the central Arctic (collaboration with sea ice physic).  

• Investigate the spatial-temporal variability of reactive gases in 
  seawater and sea-ice in relation to the distribution of algae species 
  and its effect on the aerosol production. 


Work at sea 

General sampling and biological variables 

At 11 ice stations, biological measurements were carried out (see Fig. 
3.15) starting with station 203 (1st) and ending with station 250 (11th). 
The work consisted of sampling of melt ponds (minimum 3 replicates) and 
sea-ice cores. Water from the upper 30 m below the ice was taken in 
collaboration with G. Dieckmann (AWI, CTD profile measurements) and E. 
Damm (AWI, group in charge of methane and DMS analyses). Sampling and 
measurement strategy of sack holes was made with the help of N. Cassar 
(Duke University). 

Biological ice cores were sectioned into 10 cm slices, which were diluted 
with 0.2 m filtered sea water (200 ml for each cm of ice) and thereafter 
allowed to melt during the next 24-48 hours at a temperature of 4C under 
low-light conditions. From these samples and the melt-pond water, various 
subsamples were taken for measurements of primary productivity and 
species composition (microscopy, flow cytometry, DNA and pigment 
determinations). To investigate the carbon cycle, samples for POC 
(Particulate Organic Carbon), DOC (Dissolved Organic Carbon) and TEP 
(Transparent Exopolymers) were taken. Additional subsamples of Biogenic 
Particulate Silica, PABS (Particle Absorption) and CDOM (Chromophoric 
Dissolved Organic Matter) were taken. At 6 stations, additional size-
fractionated samples (0-3, 3-10 and larger 10 m) were taken from the melt 
ponds and the lowest section of the ice cores. From under-ice water and 
sack holes only samples for pigments and flow cytometry were taken at all 
depth, while occasionally additional PP measurements directly under the 
ice were done. 

Towards the end of the cruise the spatial variability for the production 
of trace gases and ice algae in sack holes was investigated by two 
helicopter flights (Tab. 7.1) stopping randomly at 5 suitable floats each 
and samples for trace gases, nutrients, oxygen, pigments and flow 
cytometer were taken. 


Tab 7.1: Position and dates of the helicopter flights with sack-hole 
         sampling. 

   Date     12.09.2011               Date     14.09.2011  
   ————————————————————————————————  ——————————————————————————————
   (Float)  Lat.        Long.        (Float)  Lat.       Long.  
   ———————  ——————————  ———————————  ———————  —————————  ——————————
      #1    83°55.74'N  132°07.50'E     #1    83°08.80N  116°45.31E  
      #2    83°57.68'N  132°01.72'E     #2    83°09.67N  116°34.12E  
      #3    84°00.29'N  132°11.60'E     #3    83°10.16N  116°31.56E  
      #4    84°01.91'N  131°46.48'E     #4    83°10.7N   116°31.30E  
      #5    83°58.99'N  131°37.80'E     #5    83°11.5N   116°29.70E  

For the optical cores, the ice cores were divided in surface (upper 20 
cm), bottom (lower 20 cm) and the middle part. To avoid the dilution of 
the optical signal, these 112 cores were allowed to melt at 4C (within 
48-72 hours) and thereafter samples for pigments, PABS and CDOM were 
taken. These data will be used to calibrate the hyperspectral 
measurements obtained by the optical sensors (see "3. Sea ice physics"). 
For comparison of the different ice-melting techniques between the 
optical and the biological cores (with and without adding seawater) 
additional flow cytometer samples for the pico- and nano-algae were 
analysed. 

Except for PP and flow cytometer samples, all other variables were stored 
for further analysis at the AWI. 

Flow-cytometer measurements 

Flow-cytometer measurements have been carried out with an Accuri C6 flow 
cytometer. The instrument is equipped with a blue (488 nm) and a red (620 
nm) laser. To check the general performance of the instrument and to 
calibrate the Forward Scatter Signal (FSC) an Invitrogen size calibration 
kit F-13838 was used. To each sample Polychromatic latex beads (1 m, 
Polyscience) was added to monitor the optical system and to check for 
clogging of samples. The various phytoplankton types were identified by 
applying the autofluorecense of the red (FL3) versus the orange (FL2) 
channel according to Marie et al. (2005). Each sample was analysed for 3 
minutes at a custom flow rate of 100 l min-1, using a core size of 40 m. 
In total three size groups were identified: pico-plankton (0-3 m), small 
nanoplankton (3-10 m and large nanoplankton (10-25 m). To get a rough 
estimate of the biomass of each group, the FL3 (Chl a) fluorescence 
signal from each group was multiplied with the cell number and divided by 
108 to retrieve the presented arbitrary biomass values (Fig. 7.1 and 
7.2). 

Primary production measurements 

A total of 150 samples were analysed covering diverse habitats: sea ice, 
melt ponds, water under the ice and surface water (both, from ice-covered 
and non-ice-covered regions). All samples were spiked with 14C 
bicarbonate (1 µCi ml^(-1)), distributed in four plastic bottles (three 
light and one dark; 20 ml each with 35 ml headspace) and incubated in the 
laboratory for 24 hours under stable temperature and light conditions: -
1.9°C and 10 µmol photons m^(-2) s^(-1). After the incubation, samples 
were filtered through a 0.2 µm pore size nitrocellulose acetate filter 
and fumed overnight with 6 M HCl. The amount of 14C assimilated as POC 
(radioactively labelled Particulate Organic Carbon) by the cells was 
determined by liquid scintillation, adding Filter Count scintillation 
cocktail to the filters. Rates of Net Primary productivity were then 
calculated as follows: 

Primary Production rate (µgC L^(-1) d^(-1)) = 

((CPM sample-РCPM dark)•DIC•1,05)/CPM added/(100 µl* 10^(-6))•Vol•Time) 

where CPM refers to the Counts per Minute given by the scintillation 
counter and DIC is the natural dissolved inorganic carbon concentration 
of the sample. Therefore, for each sample analysed, a 2 ml subsample was 
fixed with HgCl2 in order to determine DIC concentration by flow 
injection back on land. 

Trace gases and aerosols 

Light hydrocarbons and CO concentrations were measured from different 
types of samples. While the ship was moving, continuous analysis of in-
situ surface sea water was measured. During the ice stations, a total of 
18 vertical profiles under the ice (surface level down to 30 m depth) 
were performed using a Kemmerer bottle. 20 additional samples were taken 
from the sack holes and melt ponds. Towards the end of the cruise trace 
gases where measured in water from melted ice-cores taken from the sack 
holes. 

For analysis the water was introduced in an equilibration chamber where 
dissolved gases were equilibrated with clean synthetic air, and analysed 
by a gas chromatograph (GC). Two instruments were used: a GC equipped 
with a PID (photoionization detector) for unsaturated hydrocarbon 
quantification and a GC equipped with a mercuric oxide detector for CO 
monitoring. Measurement frequency was approximately 30 minutes for 
dissolved hydrocarbons and 5 minutes for dissolved CO. Gases present in 
the ice were extracted in a different way by following the procedure of 
Xie and Gosselin (2005). 

Aerosols were continuously collected using an Aethalometer for black 
carbon assessment and an automated PARTISOL for organic aerosols in the 
CCN mode (Aerodynamic Diameter, A.D. < 0.2 µm, 6 h time resolution). 

Preliminary Results 

Flow-cytometer measurements Preliminary results of the flow-cytometer 
measurements of the melt pond water (Fig. 7.1) indicated a high spatial 
variability of the algae biomass < 25 m even within one station. Although 
the melt ponds were not always connected with the underlying water, the 
latter seems to influence the standing stocks of the melt ponds as can be 
seen by the highest observed biomass in the Atlantic sector of the 
investigation area. Small and large nano-plankton dominated the algae in 
this habitat. However, a clear preference for certain size groups 
depending on the water mass was not observed. 


Fig. 7.1: Arbitrary biomass of plankton < 25 μm for pico-plankton, small 
          nano-plankton (sm) and large (lg) nano-plankton from several 
          melt ponds (MP) at various ice stations (indicated by number). 
          Coloured rectangles around the stations indicate the three 
          different water masses based on nutrient data; red Atlantic, 
          blue Pacific and black mixed water masses. 

Fig. 7.2: As Fig.7.1 for integrated biological ice cores (ICEBIO). A 
          yellow rectangle indicates an additional mixed water mass 
          during the last two ice stations. 


Integrated concentrations of the arbitrary biomass from ice cores showed 
a similar pattern as observed for the melt ponds with highest standing 
stocks in the Atlantic sector of the investigation area (Fig. 7.2). 
However, no clear size preferences of an algae group could be attributed 
to a given water mass. Towards the end of the cruise, standing stocks of 
ice algae were very low and an effect of the progressing season cannot be 
excluded. 

Preliminary results from the CTD profiles, sack holes and under-ice water 
samples also indicated a general higher standing stock in the Atlantic 
water masses during this cruise. In contrast, Pacific water masses, 
characterized by low nitrate concentration supported only low algae 
biomass highlighting the importance of nutrients for the development of 
the Arctic ecosystem. 

Primary production 

Preliminary results of net primary productivity rates (NPP) in ice-
covered surface waters were low (<10 µgC L^(-1) d^(-1)) compared to open 
coastal waters close to the Laptev Sea (<25 µgC L^(-1) d^(-1)). (Note 
that all rates shown have not been Chl a normalized yet and have been 
calculated assuming a constant DIC of 2400 µgC L^(-1)) Preliminary rates 
were very variable and relatively low in general ranging from 0.1 to 25 
µgC L^(-1) d^(-1) (Fig. 7.3). Samples from Pacific-derived, nutrient 
depleted waters, which showed very low N:P ratios (below 2), tended to 
have lower NPP values than those from Atlantic influenced waters, 
although nutrient contents were also very low there. 


Fig. 7.3: Surface water net primary productivity rates in the central 
          Arctic at 4°C and 10 µmol photons m^(-2) s^(-1). Red 
          corresponds to Atlantic influenced water masses, orange to 
          Pacific influenced water masses and blue to coastal waters 
          close to the Laptev Sea. Stations also represent a temporal 
          sequence starting in early August and finishing in late 
          September. 


In order to investigate the nutrient limitation of phytoplankton 
communities in these different water masses, three nutrient limitation 
bioassays were performed by splitting the samples in eight different 
bottles to which different nutrient combinations were added (nitrate, 
phosphate and silicate). None of the nutrients triggered a clear increase 
in the carbon-uptake rate compared to the control, with no addition of 
nutrients. As an example, the results for the experiment performed with 
station 233, in Pacific influenced waters is shown in Fig. 7.4. 


Fig. 7.4: Nutrient bioassay from Station 233 (Pacific influenced waters). 
          Mean net-primary productivity rates of the different treatments 
          after 3 days of acclimation and 5 days incubation under stable 
          conditions: 4°C and 10 µmol photons m^(-2) s^(-1). The control 
          had no addition of nutrients and the "All" treatment had all 
          three nutrients added. Error bars indicate standard deviation 
          from three replicates. 


Sea-ice and melt-pond carbon-fixation rates have to be re-calculated with 
the real DIC values once measured. Despite the fact that the rates will 
probably decrease when the real DIC value is taken (expected to be much 
lower than in sea water because salinity is also lower in these habitats 
and salinity and DIC concentration are positively correlated), melt ponds 
and sea ice seem to highly contribute to primary productivity in the 
Arctic during late summer (Fig. 7.5). In the ice cores, NPP was 
differently distributed along the cores. For example: at the last three 
ice stations the highest rates were found in the bottom 20 cm of the ice, 
while at stations 203, 212, 218 and 222 the highest activity was detected 
in the surface 20 cm of the ice. 

Melt ponds, covering up to 60% of the ice surface, also showed a great 
variability in terms of primary productivity both in and between 
stations. Several melt pond samples were analysed under the microscope, 
revealing complex communities 117 formed by several diatom species (many 
of them dead or in resting spore state), dinoflagellates, turbellaria, 
rotifers, ciliates, foraminifera. Grazing could be observed to be a very 
active process but was not quantified. 

In summary, high spatial variability of PP, both in sea-ice cores and 
melt ponds, was the main characteristic of the Arctic summer ice sampled 
during this cruise. Together with the large small-scale variability makes 
up scaling of carbon fixation rates to the entire Arctic a challenging 
task. 


Figure 7.5: Relative contributions to primary productivity of the 
            different habitats: melt ponds, sea ice, water under the ice 
            and surface water in each ice station. Calculated using non-
            biomass normalized rates and constant sea-water DIC 
            concentrations for all habitats. 


Trace gases 

Data processing is still on the way; the full interpretation will be made 
using the biological measurements and the physical parameters measured 
during the samplings. 

A preliminary vertical profile (Fig. 7.6) for the different variables 
(total light hydrocarbons, isoprene, propene (C3H6) and CO) depict that 
concentrations observed for each compound in sack holes were much higher 
than the concentrations in the water column. In addition, CO 
concentrations were by an order of magnitude higher than the hydrocarbon 
concentrations. For all gases a strong vertical gradient in the very 
shallow water layers (1-2 m) was observed. These general findings were 
systematically found on all other investigated profiles. 

Aerosols filters will be analysed in the home laboratory. 


Fig. 7.6: Vertical profiles of propene (C3H6), isoprene, of total light 
          hydrocarbons (Hc) and carbon monoxide (CO) from Station 222 
          under the ice in comparison to the sack holes sampled on the 
          ice. (Note that all concentrations are not finally calibrated 
          yet and that the CO concentrations from the sack holes were 
          divided by 10 for better readability). 


References 

Marie, D., Simon, N. & Vaulot, D. (2005) Phytoplankton cell counting by 
    flow cytometry, in: Algal Culturing Techniques, edited by: Andersen, 
    R. A., Elsevier Academic Press 

Xie, H. & Gosselin, M. (2005) Photoproduction of carbon monoxide in 
    first-year sea ice in Franklin Bay, southeastern Beaufort Sea, 
    Geophys. Res., Lett., 32, doi:10.1025 




7.2  Plankton Ecology and Biogeochemistry in a Changing Arctic Ocean 
     (PEBCAO) 

     Antje Boetius, Alexandra Cherkasheva,  Alfred-Wegener-Institut 
     Estelle Kilias, Ilka Peeken, 
     Olivia Serdeczny 
     Not on board: Eva - Maria Nöthig 


Objectives 

The project PEBCAO (Plankton Ecology and Biogeochemistry in a Changing 
Arctic Ocean) is focused on studying plankton and microbial processes 
relevant for biogeochemical cycles in the Arctic Ocean. In order to 
understand and track consequences of climate change for the pelagic 
ecosystem, both long-term field observations and experimental work with 
Arctic plankton species and communities are needed to gain knowledge 
about their feedback potential in the future Arctic Ocean. 

Biogeochemistry, phytoplankton & vertical particle flux 

Recent investigations indicate that rising temperatures and freshening of 
polar surface waters promote a shift in the phytoplankton community 
towards a dominance of smaller cells. A change in size of the primary 
producers could have significant consequences for the entire food web and 
for the cycling and sequestering of organic matter. An increase in ice-
free areas as well as CO2- and temperature-related changes will also 
affect plankton and the carbonate chemistry of the ocean; even small 
changes in the biological pump could significantly affect atmospheric CO2 
concentration. In such a scenario, picoplankton can comprise a large pool 
of biomass and can attain high abundances. Therefore, we particularly 
need to understand how environmental parameters influence the diversity, 
occurrence and distribution of the picoplankton. 

In this context, results collected during this cruise will be compared 
with results obtained during former cruises to answer questions like: Is 
there a shift of the phytoplankton community towards smaller cells? Are 
there any intrusions of Atlantic species into the Arctic Ocean? How does 
the phytoplankton community differ between different water masses? Do 
observed changes in the pelagic realm influence the vertical particle 
flux of organic matter? 

Primary production & phytooptics 

At high latitudes ocean color satellite data have a sparse coverage due 
to the presence of sea ice, clouds and low sun elevation angles. This is 
the main cause that satellite ocean colour algorithms which achieve 
large-scale information on primary production perform poorly in these 
regions.  Therefore, our main aim for TransArc was to collect in-situ 
data that allow us to adopt satellite global primary production 
algorithms (as far as the satellite reaches northern latitudes) for the 
Arctic Ocean. Furthermore, in-situ optical measurements and the 
photosynthetic characteristic of phytoplankton in the central part of the 
Arctic Ocean were sampled because so far only a few data of phytoplankton 
characteristics on larger temporal and spatial scales than obtained from 
discrete water samples exist. 

Work at sea 

Samples have been collected along two transects; some additional stations 
were sampled in the outer Laptev Sea. In addition, surface water was 
sampled along the ship’s route (see Fig. 7.7). 


Fig. 7.7: Stations sampled by the PEBCAO group 


Biogeochemistry, phytoplankton & vertical particle flux 

Samples for phytoplankton ecology investigations were taken from the CTD-
rosette at 87 stations at 5 to 8 depths according to the water mass 
structure (at 66 stations the upper 70 m were sampled, at 21 stations the 
upper 200 m were sampled). On 10 of the stations, under-ice plankton was 
sampled at 0.5, 1 and 5 m, respectively. Ocean surface water was sampled 
every 20-60 miles from the ship’s flow through membrane pump at 97 spots. 
At all 87 stations and at the 97 spots, samples have been taken for 
analysing biogeochemical and biooptical parameters such as chlorophyll a, 
pigments (HPLC), absorption of particulates, CDOM and phytoplankton and 
CDOM fluorescence. Samples to determine seston, particulate organic 
carbon (POC), particulate organic nitrogen (PON), and particulate 
biogenic silica (PbSi), phytoplankton and protozooplankton were taken at 
selected stations. The water was filtered through pre-combusted Whatman 
GF/C glass-fiber filters, polycarbonate and, cellulose acetate filters 
and stored deep-frozen at -20°C or -80°C for later analyses in the home 
laboratory. The abundances of autotrophic pico- and nanoplankton, and 
small microplankton were determined with the flow cytometer directly on 
board. Microscope identification and enumeration of larger nanoplankton 
and microplankton will be carried out later in the home laboratory at 
AWI. Samples are preserved and stored at a cool and dark place. 

Due to the small size and thus complicated phenotypic characterization 
the smallest phytoplankton fraction, picoplankton (0.2-2.0 µm), is 
difficult to detect and assess. However, a proper identification down to 
the species level can be achieved by the application of molecular 
methods. Thus, in order to investigate the genetic diversity of 
picoeukaryotes special filter samples for DNA analyses were taken during 
the cruise. Additionally, some water samples were taken into culture for 
later microscopy analyses. Surface water samples were taken twice a day 
from the membrane pump and 3 depth were sampled from 58 CTD casts. 
According to the fluorescence probe profile, one sample was taken from 
the surface layer, one from the chlorophyll maximum and one from a depth 
of approximately 50 m. For the DNA analyses a size fractionation was 
performed. Two liters of the water sample were first filtered through a 
membrane filter (Millipore) with a pore size of 10 m. Afterwards the flow 
trough was filtered through a second membrane filter with a pore size of 
3 m and finally the flow trough of the previous filtration was filtered 
through a membrane filter with a pore size of 0.4 m. All in all, three 
different phytoplankton size fractions were achieved from every water 
sample taken, above 10 m, between 3 and 10 m and between 0.4 m and 3 m. 
After filtration the samples were stored immediately at -80°C. 

Vertical particle flux of particulate matter under the almost permanent 
ice cover will be investigated by means of sediment traps which were 
deployed in two moorings near the Gakkel Ridge (two in the Nansen Basin 
and two in Amundsen Basin; both deployed at ~200 m & ~150 m above the sea 
floor) for one year (see oceanography, chapter 4). The traps were 
equipped with 20 sampling jars each and pre-programmed individually. They 
will be recovered in summer 2012 during the Polarstern expedition 
"IceArc" (ARK-XXVII/3).  

Primary production & phytooptics 

In-situ radiance and irradiance measurements at high spectral resolution 
down to 110 m have been carried out using a TriOS RAMSES radiometer. 
Every measurement includes spectra of downwelling irradiance (sensor 
5038), upwelling irradiance (sensor 81EA) and upwelling radiance (sensors 
82D6 and 81E6). These data will later be used to validate radiative 
transfer modeling through the water column. 

The photosynthetic characteristic of phytoplankton has been investigated 
by measurements of the variable fluorescence in the upper 110 m. A 
FastTracka Fast Repetition Rate Fluorimeter (FRRF) exposes phytoplankton 
to a series of flashes of blue light at 200 kHz repetition rate and then 
records the fluorescence signal. From this signal the efficiency of the 
photochemical conversion during photosynthesis of the observed algal 
population was calculated. The data will be later processed with e.g. 
"Submersible FRRF Data Reduction - FRS1" software. These estimates will 
be used to validate one of the key parameters in satellite primary 
production modeling - the photosynthetic yield. 

Preliminary/expected results 

All samples have to be finally analyzed in the home laboratory at AWI. 
Results obtained with the flow cytometer showed distinct differences 
between Atlantic and Pacific influenced water masses with much higher 
cell concentrations in the 'Atlantic part' of the Arctic Ocean with 
highest counts at the beginning of the cruise in early August. To 
investigate the community structure and the diversity of picoeukaryotes, 
ribosomal fingerprinting technology (ARISA) as well as pyrosequencing 
will be applied. We speculate to find less biomass and a trend towards 
smaller cells in comparison with results obtained during former cruises. 
Combined with the data collected for chlorophyll a and phytoplankton 
specific absorption the optical measurements will serve as ground truth 
data for the adaptation of the global satellite primary production 
algorithm to the Arctic Ocean. 



7.3  Zooplankton investigations  

     Hans-Jgen Hirche(1),              1 Alfred-Wegener-Institut
     Russell R. Hopcroft(2),           2 UAF
     Ksenia N. Kosobokova(3),          3 SIO
     Elizaveta A. Ershova(2)  


Objectives 

What drives the productivity of the Arctic Ocean has remained a central 
question in polar research for more than a century. Given the extreme 
seasonality of this habitat, how do organisms persist over the prolonged 
periods of low primary productivity? Investigations in the Greenland Sea 
and Eurasian Basin in the early 1990s demonstrated that the composition 
and distribution of pelagic fauna in the Arctic Ocean is strongly 
affected at regional and even basin scales by the inflow of Atlantic 
water (Hirche & Mumm, 1992; Mumm, 1993; Kosobokova & Hirche, 2000) that 
enters via Fram Strait and from the Barents Sea shelf into the Eurasian 
Basin (Hirche & Mumm, 1992; Kosobokova & Hirche, 2000). The environmental 
niche - preferences and tolerances - of these advected species then 
determines their success at inhabiting the Arctic basins.  While many 
expatriated species die off shortly after entering the Arctic Ocean, 
others survive due to their starvation potential, or even continue their 
development for some time, such that the distribution of those 
unsuccessful is dependent on a combination of transport velocity and 
survival time. 

Given their connection to adjoining waters, as well as local 
productivity, the Arctic’s biological communities are sensitive to changes 
in circulation as well as sea ice cover. During the 1990s, various 
observations indicated that the properties and circulation of Atlantic-
derived water in the Arctic Ocean had changed considerably. In the 
Eurasian Basin, the Atlantic layer became warmer and saltier (Schauer et 
al., 2004) and the boundary between the Atlantic and Pacific waters moved 
further into the Canada Basin (McLaughlin et al., 2002). A simple 
increased advection of Atlantic populations might only increase the 
sedimentation of advected biogenic material, however, coincident warming 
could also favor the survival of the Atlantic communities, provided there 
is adequate food to sustain them. Given sufficient warming, expatriated 
fauna might begin to replace the resident Arctic fauna which is 
characterized by slow growth and low biomass (Hirche & Mumm, 1992; 
Kosobokova & Hirche, 2000, 2009; Hirche & Kosobokova, 2007). The 
situation is further complicated by the pronounced decline of summer sea 
ice cover observed over the past decade. 

In order to understand the processes and factors regulating the survival 
of both the advected Atlantic zooplankton and the resident fauna within 
the Arctic Ocean, the work of the zooplankton team focused on the 
following tasks: 

Patterns 

Relate the composition, abundance, biomass and spatial distribution of 
zooplankton communities across the basins and ridges to water circulation 
patterns and primary productivity. Determine the present environmental 
status of the Arctic Ocean, compare it to earlier cruises, and improve 
projections of future status or change. 

Rates 

Relate the reproductive state of dominant copepod species to 
environmental factors, including the continued analyses of biochemical 
composition (i.e. lipid storage) and stable isotopes to understand the 
life strategies and trophodynamic relationships of species. 

Genetics 

Build the DNA sequence library needed for emerging molecular approaches 
to community structure. Determine if regional or basin-scale population 
structure exists within the Arctic using molecular markers. 

Outreach 

Share the diversity of the Arctic planktonic life through images and 
public resources. 


Work at sea and preliminary results 

Sampling 

For the investigation of species composition and distribution, 
zooplankton were collected by a multiple closing net (Model MAXI, 0.5 m2 
mouth opening, Hydrobios, Kiel). The Mutinet was equipped with 150 m mesh 
nets and provided stratified sampling of the entire water column from the 
surface to the bottom at a total of 29 stations, with two sequential 
casts occurring at one deeper station (Fig. 7.8 and Tab. 7.2). Sampling 
was carried out on two large transects covering all basins and crossing 
all ridges of the Arctic Ocean. From five to seven layers were sampled in 
the shelf and continental slope regions, and from nine to fifteen layers 
at stations off the shelf. The majority of stations were taken in the 
deep region (21 stations total, eleven of them deeper than 3000 m, plus 
four deeper than 4000 m), while five were taken in the slope region, and 
only three in the shelf region (depths <400 m) (Tab. 7.2). The samples 
were preserved in 4% borax-buffered formaldehyde for later processing. 

Live animals for experiments, and for biochemical and physiological 
measurements, were collected in the upper 300 m with a bongo net (300 m 
and 500 m mesh), or from a 60 cm diameter (300 m mesh) net attached to 
the outside of the Multinet. 

Genetics 

It is proposed that in the future, the diversity within zooplankton 
samples will be determined via high throughput molecular sequencing. Such 
technologies will require a complete "Library" of the target sequences to 
ultimately determine the species they represent. During the cruise, a 
total of 139 planktonic metazoan species were identified within our non-
quantitative live samples. Representatives of each were removed, placed 
in 95% ethanol, and stored at -80°C for later determination of their COI 
sequences plus some additional mitochondrial or nuclear target regions. 
This yield represents the majority of the zooplankton species known from 
the Arctic basins, with only the rarest species still remaining 
unsampled. For the three most dominant copepod species - Calanus 
hyperboreus, C. glacialis, and Metridia longa - samples are prepared to 
explore population genetics at high spatial resolution.  The relative 
availability of most other species will restrict our analysis to a simple 
comparison of the Eurasian to the Amerasian basin populations. 


Fig. 7.8: Station map of zooplankton sampling 


Tab. 7.2: Zooplankton sampling stations 

ARK                                                           Egg
26/3     5.8.-7.10.2011                                 production expts  
————————————————————————————————————————————————————  ———————————————————
Station    Date    Lat (N)  Lon         MN/    Bongo      C.     Metridia 
                                     #samples         glacialis   longa  
———————  ————————  ———————  ———————  ————————  —————  —————————  ————————
  188        9.8.  82°10'    60°E      220/5    200        x        x  
  190        9.8.  82°36'    59°55'E   270/5    200        x        
  191       10.8.  82°50'    60°E      960/7    300        x        x  
  193    10/11.8.  83°45'    59°58'E  3000/9    300        x        
  196       12.8.  83°52'    60°30'E  3570/9   1500        x        
  201    13/14.8.  85°31'    59°53'E  3900/9    500        x        x  
  204       15.8.  86°14'    59°23'E  3200/9    300        x        x  
  208       17.8.  86°51'    60°11'E  2850      300        x        x  
  210       18.8.  87°17'    59°57'E  4180      300        x        x  
  212a      19.8.  87°17'    59°38'E   760      300        x        x  
  212b      20.8.  88°01'    59°03'E  4320     
  215       21.8.  89°11'    61°04'E  4325      300        x        x  
  218       23.8.  89°53'    54°07'E  4250      300        x        x  
  220       24.8.  89°16'   117°03'W  2050      300        x        x  
  222       26.8.  88°45'   128°19'W  3900      300        x        x  
  225       28.8.  87°39'   157°37'W  2350      300        x        x  
  227       29.8.  86°52'   155°06'W  3815      300        x        x  
  230        1.9.  85°04'   137°11'W  1800      300        x        x  
  235        3.9.  83°01'   129°59'W  3450      300        x        x  
  239        6.9.  84°05'   164°13'W  1960      300        x        x  
  245        9.9.  84°48'   166°31'W  3350      300        x        x  
  247       10.9.  84°44'   155°36'W  2180                 x        x  
  249       11.9.  84°31'   144°37'E  1980                 x        x  
  250       11.9.  84°22'   139°50'E  3650                 x        
  263       15.9.  82°36'   108°24'E  3525                 x        x  
  266       16.9.  81°39'   104°01'E  2980                 x        x  
  267       17.9.  81°29'   103°10'E  2530                 x        x  
  268       17.9.  81°16'   102°39'E  2170                 x        x  
  269       17.9.  81°07'   102°15'E  1385                 x        x  
  270       18.9.  80°58'   101°51'E   370                 x        x  


Image library 

During this cruise, we have continued to build on efforts begun under the 
ArcOD project of Census of Marine Life program to create an image library 
for metazoan Arctic zooplankton.  About 1800 digital images have been 
taken during the cruise, encompassing most of species encountered.  These 
images will begin to appear on the Arctic Ocean Diversity website 
(http://www.arcodiv.org), as well as the Encyclopedia of Life 
(http://www.eol.org), post-cruise. 

Distribution and condition of three dominant copepods in relation to 
hydrography 

Substantial numbers of the copepods Calanus hyperboreus and Metridia 
longa are probably advected into the Arctic Basin within the Atlantic 
Inflow from the Greenland Sea, while many C. glacialis originate from 
adjoining marginal seas, like the Barents or Kara seas. In order to 
understand and predict their fate in the Arctic Ocean, we documented 
their body’s dry weight, lipid content, and reproductive state. 

Dry mass 

Dry mass is a general parameter integrating all body compounds. It will 
be determined from females and copepodite stage V of specimens sorted 
alive and then deep frozen at -25°C). 

Lipids 

Lipids are accumulated during the productive Arctic summers. They are 
used as energy reserves to sustain animals during the winter, and for 
gonad maturation and egg production during the following season.  
Measuring the volume of the lipids accumulated provides an index of how 
successful the species has been in a given year, and how this varies 
regionally.  During the cruise, we have imaged copepodite stages V and VI 
of C. hyperboreus and C. glacialis at each station. From sets of 50 
animals per stage per species (ca. 5800 animals in total) we will 
determine body size and lipid volumes by semi-automated image analysis. 
These estimates will be compared to - and calibrated with - the measured 
mean-dry mass of the animals imaged. 

Egg production 

Egg production is a direct measure of reproductive activity of a 
population. Egg production experiments were set up for C. glacialis and 
M. longa at all stations. No experiments were conducted with C. 
hyperboreus, as this species spawns only in winter (Hirche and Niehoff, 
1996). Typically, 48 single females of C. glacialis were incubated for at 
least 48 hours in 15 ml cell wells.  C. glacialis laid eggs in only 5 of 
the 29 experiments, and only in the Eurasian Basins during first half of 
August at locations observed to have higher chlorophyll concentrations. 

Eggs production experiments 

Eggs production experiments with Metridia longa were conducted at 25 
stations (Tab. 7.2). On each station, 48 females were sorted from the 
bongo net samples and then set individually into 70 ml towers filled with 
filtered sea-water. The towers contained a 300 m mesh positioned 0.5 cm 
above the cell bottom, which allowed the eggs to fall through thereby 
avoiding egg disturbance or cannibalism (Hopcroft et al., 2005). Females 
were kept at 0°C for 48-96 hours, during which eggs were produced from 20 
of 25 stations. Eggs were counted upon termination of the experiment; 
eggs-laying females were individually preserved in formalin for later 
measurements. From several stations (St. 188, 191, 193, 204), egg-laying 
females were kept an additional 3 weeks to monitor egg production under 
starvation conditions, during which time egg production slowly/rapidly 
declined. At these same stations, eggs were kept to monitor hatching 
success rate and hatching time. Generally, eggs took 5-7 days to hatch; 
most of the eggs that did not disintegrate in the first 1-2 days ("good" 
eggs) and hatched successfully into nauplii. The percentage of "good" 
eggs varied from station to station; from female to female; and even in 
different clutches of the same female. An additional 50 M. longa females 
were incubated from the beginning of the cruise in filtered sea water to 
study longer-term mortality rate due to starvation: nearly all survived 
the entire 5 weeks. 

Egg production and starvation of mesopelagic species 

Egg production experiments were also carried out on Spinocalanus horridus 
from stations 225 and 229, Scaphocalanus acrocephalus from St. 212 and 
Heterorhabdus norvegicus from stations 250 and 267. Females were set 
individually in 15 ml cell wells in filtered sea-water and monitored 
daily for produced eggs. Eggs were produced by 3 Spinocalanus horridus 
females, by 2 Scaphocalanus acrocephalus and by a single Heterorhabdus 
norvegicus. 

Patterns 

The pattern of zooplankton abundance and biomass are typically determined 
post-cruise, however, the four dominant calanoid copepod species (Calanus 
hyperboreus, C. glacialis, C. finmarchicus and Metridia longa) were 
enumerated in the preserved Multinet collections from about half the 
stations during the cruise. All copepodite stages of the four species 
were counted in the entire sample. Prosome length was used to distinguish 
the young stages (CI-CIII) of three Calanus species as well as adults and 
CVs of the closely related C. glacialis and C. finmarchicus, according to 
Hirche & Kosobokova (2011). The highest abundances were found along the 
slopes and over the ridges, with all copepodite stages observed in C. 
hyperboreus, C. glacialis, and Metridia longa, but only late copepodites 
observed for C. finmarchicus. The population stage composition helps to 
better understand the reproductive status of these populations and their 
life histories. It indicates that C. finmarchicus does not reproduce 
within the Arctic Ocean. Biomass will be calculated from published 
(Richter, 1994) and unpublished taxon-specific length-dry weight (DW) 
relationships, and individual dry weights (Kosobokova et al., 1998). 
These data, and that added post-cruise, on zooplankton in the four major 
basins of the Arctic Ocean will be related to hydrography, bottom 
topography and the distribution of primary production to better elucidate 
their distributional patterns. 


References 

Hirche, H.J. & Mumm, N. (1992). Distribution of dominant copepods in the 
    Nansen Basin, Arctic Ocean, in summer. Deep-Sea Res. 39 Suppl. 2: 
    S485-S505. Hirche, H.J. & Niehoff, B. (1996). Reproductionof the 
    Arctic copepod Calanus hyperboreus in the Greenland Sea - field and 
    laboratory observations. Polar Biol.16: 209-219. 

Hirche, H.J. & Kosobokova, K.N. (2007). Distribution of Calanus 
    finmarchicus in the northern North Atlantic and Arctic Ocean -
    expatriation and potential colonization. DPR II, 54: 2729-2747. 

Hirche, H.J. & Kosobokova, K.N. (2011). Winter studies on zooplankton in 
    Arctic seas: the Storfjord (Svalbard) and adjacent ice-covered 
    Barents Sea. Marine Biology 158:2359.2376 

Hopcroft, R.R., Pinchuk, A.I., Byrd, A. & Clarke, C. (2005). The paradox 
    of Metridia spp. egg production rates: A new technique and 
    measurements from the coastal Gulf of Alaska. Mar. Ecol. Prog. Ser. 
    286: 193-201. 

Kosobokova, K.N. (1998). New data on the life cycle of Calanus glacialis 
    in the White Sea based on seasonal observations of its genital system 
    development. Oceanology 28 (3):347-355 

Kosobokova, K,N. & Hirche, H.J. (2000). Zooplankton distribution across 
    the Lomonosov Ridge, Arctic Ocean: species inventory, biomass and 
    vertical structure. Deep-Sea Res. I 47: 2029-2060. 

Kosobokova, K.N. & Hirche, H.J. (2009). Biomass of zooplankton in the 
    eastern Arctic Ocean - a base line study. Prog. Oceanogr. 82:265-280. 

McLaughlin, F., Carmack, E., MacDonald, R.W., Weaver, A.J. & Smith, J. 
    (2002). The Canada Basin 1989б995: Upstream events and farfield 
    effects of the Barents Sea. J. Geophys. Res. 107, 
    doi:10.1029/2001JC000904. 

Mumm, N. (1993). Composition and distribution of mesozooplankton in the 
    Nansen Basin, Arctic Ocean, during summer. Polar Biol. 13: 451-461. 

Richter, C. (1994). Regional and seasonal variability in the vertical 
    distribution of mesozooplankton in the Greenland Sea. Berichte zur 
    Polarforschung, 154: l-87 

Schauer, U., Fahrbach, E., Osterhus, S. & Rohardt, G. (2004). Arctic 
    warming through the Fram Strait: Oceanic heat transport from 3 years 
    of measurements. J. Geophys. Res. 109(C06026), 10.1029/2003JC001823. 




8.  MARINE GEOLOGY  

    Tina Kollaske(1), Jens Matthiessen(1),    1 Alfred-Wegener-Institut
    Ann-Katrin Meinhardt(2),                  2 Institute for Chemistry
    Norbert Lensch(1), Patricia Slabon(1),      and Biology of the Marine
    Mirko Sühs(1), Hao Zao(1)                   Environment, Oldenburg  


Introduction and objectives 

The overall goals of the marine-geological research programme are (1) 
high-resolution studies of changes in paleoclimate, paleoceanic 
circulation, paleoproductivity, and sea ice distribution in the Central 
Arctic Ocean and at the adjacent continental margins during the 
Quaternary, and (2) the long-term history of the Mesozoic and Cenozoic 
Arctic Ocean and its environmental evolution from a (sub-)tropical to an 
ice-covered polar ocean. In areas such as the Alpha-Mendeleev Ridge, pre-
Quaternary sediments are cropping out close to the seabed, which could 
even be cored with coring gears aboard Polarstern and which would allow 
to study the Mesozoic/Tertiary history of the (preglacial) Arctic Ocean. 
Especially, data for the reconstruction of the long-term paleoclimatic 
history of the Arctic Ocean are sparse. 

A large set of sediment cores from the eastern Arctic Ocean has been 
studied in the past 20 years resulting in relatively well-constrained 
spatial reconstructions of paleoceanographic variability in the Eurasia 
Basin and of the marine part of ice sheets in Eurasia in the Middle to 
Late Pleistocene. Reconstructions for the western Arctic are still based 
on comparably few records, and in particular the central regions such as 
the Alpha Ridge have been mainly sampled from drifting ice islands in the 
1960s and 1970s due to the inaccessibility for surface ships. Since 
Polarstern has collected sediment cores for the first time at the western 
Alpha and northern Mendeleev Ridges during ARK-XIV/1a in 1998, sea-ice 
cover in the Arctic Ocean has deteriorated considerably. It reached a 
historical low in extent in 2007, and Polarstern could sample again the 
western Alpha Ridge during ARK.XXII/3. Therefore, it was attempted during 
ARK-XXVI/3 to break through to the eastern Alpha Ridge where, besides 
Pleistocene sediments, isolated occurrences of Mesozoic and Paleogene 
sediments have been cored by chance from drifting ice islands. Recoring 
at these sites had a high priority because knowledge of the Pre-
Pleistocene history of the Amerasia Basin is just based on data from 
these four locations. However, two attempts during this expedition failed 
due to the presence of multi-year sea ice despite a generally low extent 
of sea ice in 2011. Thus, the central Alpha Ridge may still be reached by 
Polarstern only if supported by a second icebreaker. 

The new results will be related to those obtained from previous 
expeditions to the Central Arctic Ocean and the Eurasian continental 
margin. It was the aim of this expedition to fill gaps in the network of 
sediment cores collected during expeditions ARK-XIV/1a, ARK-XXII/3 and 
ARK-XXIII/3 at the western Alpha and Mendeleev Ridges that is required to 
study regional changes in paleoclimate, paleoceanic circulation, 
paleoproductivity, sea-ice distribution and ice sheet dynamics on the 
surrounding continents in the Pleistocene in a relatively high 
resolution. Furthermore, the mapping of key lithological layers may allow 
the correlation paleoenvironmental events across the Arctic Ocean. In 
this framework, the geological programme included specific projects, e.g. 
mapping sea floor structures along the ships track by swath bathymetry 
and sediment echosounder, re-sampling stations visited during ARK-VIII/3 
and ARK.IX/4 in 1991 and 1993, respectively, to possibly identify the 
impact of recent climate change on benthic foraminifer faunas, and 
collecting surface sediments for calibration of paleoceanographic proxies 
such as biomarkers, benthic foraminifer faunas, and stable oxygen and 
carbon isotope composition of planktic and benthic foraminifers. Finally, 
inorganic geochemistry studies, initiated during ARK-XXIII/3 in 2008 to 
unravel the origin of manganese-rich layers in the Arctic Ocean, were 
continued to supplement the records from the East Siberia continental 
margin with data sets from the various basins visited during the 
expedition. In the following, we will describe the methods related to 
work during the expedition. 

The geological station work was conducted along the oceanographic 
transects outside the Russian EEZ. Sites on submarine highs were selected 
for coring by using information on sea floor and sub-bottom structure 
from swath bathymetry and sediment echosounding (Hydrosweep and 
Parasound) to obtain hemipelagic sedimentary records not overprinted by 
sediment redeposition. Surface and sub.surface sediments were taken by 
gravity corer, giant box corer, and multicorer. 



8.1  Multi-beam bathymetry 

     Patricia Slabon                        Alfred-Wegener-Institut 


Objectives 

The main task of the bathymetric work was to conduct multibeam (MB) 
surveys in support of the geological and oceanographical programs using 
the new Hydrosweep DS-3 system (Atlas Hydrographic) and monitor the data 
acquisition to ensure high resolution spatial depth information 
throughout the expedition. Due to the reduced number of MB-staff, no data 
processing was carried out. The recorded MB-data is a valuable 
contribution to datasets of IBCAO (International Bathymetric Chart of the 
Arctic Ocean) and GEBCO (General Bathymetric Chart of the Ocean). 

Another interest was to create a progress report about the new operation 
software of Hydrosweep DS-3 and the acquisition system HYPACK, which were 
installed in October 2010. Several open questions remained after the 
acceptance test and sea trials, which were reviewed during this cruise in 
detail. All problems concerning data collection and visualization were 
reported to the corresponding companies. Jointly with the system 
manufacturer and HYPACK it was tried to solve these problems. 

Work at sea 

The multibeam survey was started on August 6, 2011 at 9:00am UTC for 
testing purposes. After solving several technical problems, data 
acquisition was started in the main research area on August 13 at 8:47am 
UTC within the Norwegian EEZ and was continued until September 22 at 
7.30pm UTC, before entering the Russian EEZ. No data acquisition was 
carried out within the Russian EEZ. 

At the beginning of the cruise, Hydrosweep (Hydromap Control) caused 
several system errors that generally were solved by total system shut 
down and restart. The HYPACK software caused also problems that forced 
repeatedly a restart of the system. Apart from all technical problems, 
HYPACK and Hydrosweep operated relatively stable. Runtime errors, 
occurring randomly, did not require any repair or a complete reboot of 
the system. 

When leaving the Russian EEZ on September 29 at 3:29pm UTC into 
international waters and entering the Norwegian EEZ, data acquisition was 
continued until October 3, 2011 at 9:31am UTC. During the transit to 
Bremerhaven, heavy sea off the Norwegian coast caused systematic errors 
and thus poor depth measurements, obviously due to unsatisfactory 
measurements of ships attitude. These effects were mainly observed in 
shallow water regions. 

In the deep-sea, Hydrosweep was operated in Equal Footprint Beam Spacing 
mode using a defined number of 345 beams per ping. The used frequency is 
15.5 kHz. The aperture angle of the sonar fan can be selected between 
several predefined seafloor coverages. During this cruise an opening 
angle of 100% starboard/100% portside, depending on the water depth was 
used. A larger angle of 200%/200% created low resolution and poor data 
quality. Only in shallow waters between 100 m and 350 m the wider swath 
of 200%/200% was chosen. In waters less than 100 m, resulting depths show 
systematic errors in particular in the outer beams. In areas with water 
depths of less than 100 m an angle of 150%/150% was used. 

Data acquisition was conducted using HYPACK software. The recorded data 
is stored in files of 30 minutes time interval in the internal HYPACK raw 
formats *.HSX and *.RAW (e.g.: ARK26-3_2011__2291239_0.HSX). In areas 
exceeding 84N the universal polar stereographic projection (UPS) was used 
for visualization, otherwise the UTM projection. As data processing was 
not carried out, only selected files were checked for correct values of 
heading and course over ground (CoG) by comparing the MB-data to the D-
SHIP Navigation files. Furthermore some files were visualized and checked 
using CARIS HIPS. For the generation of working maps onboard, few data 
were exported as ASCII files (longitude, latitude, depth). 

During Hydrosweep operation, the actual swath is displayed on the screen. 
This information is used to find suitable locations especially for the 
marine geological work in real time. Due to technical problems regarding 
the import of the SVP (Sound Velocity Profile) into Hydromap Control, 
correct multibeam depths were not available. 

Echo sounders derive the water depth from the travel time of the acoustic 
signal running from the transducer to the sea floor and back to the 
receiver. The exact sound velocity in the water column, which depends on 
pressure, temperature and salinity, is needed. The depth precision can 
vary strongly due to regional and local variations of the physical 
parameters in the water column that affect the sound velocity. A well-
established technique to derive the water sound velocity is to perform 
CTD (Conductivity, Temperature and Depth) casts. 

The *.cnv files, derived from the CTD values, containing the water depth 
and the matching sound velocity were processed in the sound velocity 
profile viewer and stored as *.vel-file for HYPACK/HYSWEEP and without 
extension for the ATLAS SENSOR MANAGER. The ATLAS SENSOR MANAGER reads 
sound velocity profiles containing up to 128 points and imports the 
profile into Hydromap Control. 27 CTD-Profiles were processed and used 
for the water sound velocity correction. 

During transits no sound velocity profiles were available. Hence the 
recorded measurements must be processed using external sound velocity 
data as available for example from ODV (ocean data view), before using 
them for mapping purposes. 

Preliminary results 

During the expedition a nearly continuous recording of data was achieved, 
except for few gaps caused by unexpected system errors and shutdowns. 
During 36 days of work in the main search area, a profile length of about 
3480 nm (6450 km) was surveyed, generating 7.2 m. pings and 102 bn. beams 
(before editing). The amount of raw data storage volume is 18.5 GB 
created by 3778 separate files divided into *.HSX- and *.RAW-files. The 
observed depths vary between less than 100 meters in the coastal regions 
of Norway and Greenland and up to 5300 meters in a central valley of the 
Gakkel Ridge. 

Despite the almost permanent ice coverage and the mentioned problems the 
system worked over periods reliable and provided high quality data. Some 
disturbances in the data could not be avoided during ice breaking. 

The GEBCO_08 -Grid (General Bathymetric Chart of the Oceans) gives an 
overview on the morphology of the region. These data can be used for 
general planning. The recorded data differ at several places, due to the 
low resolution (2 km x 2 km) of the global GEBCO dataset, which is partly 
based on derived satellite gravity data and sparse bathymetric echo 
sounder data collected by submarines and icebreakers. 

The difference between the GEBCO_08 model and the multibeam data are 
shown in Fig. 8.1. 


Fig. 8.1: Example of differences between bathymetry at the Karasik 
          Seamount from IBCAO (contour lines) and unedited multibeam 
          bathymetry of this cruise (color coded and shaded). 




8.2  Marine sediment echosounding using Parasound 

     Jens Matthiessen, Tina Kollaske         Alfred-Wegener-Institut 


Objectives 

The structure of bottom and sub-bottom sediments was characterized by its 
acoustic behaviour as recorded in reflection patterns of the hull-mounted 
Parasound system. It was used routinely during the expedition to select 
coring stations based on acoustic pattern and backscatter, and to record 
the acoustic facies along the ships track. 

Work at sea 

The Parasound system generates two primary frequencies that may be chosen 
between 18 and 23.5 kHz and are transmitted in a narrow beam of 4 at high 
power. Two secondary harmonic frequencies are generated by the so-called 
"Parametric Effect", caused by the non-linear acoustic behaviour of 
water, one of these is the difference (e.g. 4 kHz) and the other one the 
sum (e.g. 40 kHz) of the two primary frequencies, respectively. Sub-
bottom penetration may be up to 200 m (depending on sediment conditions) 
with a vertical resolution of ca. 30 cm. Since the sediment-penetrating 
pulse is generated within the narrow beam of the primary frequencies, 
lateral resolution is very high compared to conventional 4 kHz-systems. 

The Deep Sea Sediment Echo Sounder Parasound (Atlas Hydrographic, Bremen, 
Germany) was upgraded from DS II to DS III-P70 in 2007 and was thoroughly 
tested during three sea-trials (for a summary see Niessen & Matthiessen 
in Jokat, 2009). Details of this system have been described by Niessen et 
al. (in Klages & Thiede, 2011, in Schiel, 2009, and in Macke, 2009). 
Information about system set up, the hardware and software may be found 
in Niessen & Matthiessen (in Jokat, 2009) and the operator manuals of 
Atlas Hydromap Control and Atlas Parastore. The selected modes of 
operation, sounding options and ranges used during the cruise are 
summarized in Tab. 8.1. The Hydrosweep depths had to be used as system 
depth source during the latter part of the expedition because the DWS 
(Deep Water System; Simrad Echosounder) system completely failed. 

During ARK-XXIII/3 in 2008 the new system was tested under relatively 
light ice conditions while here it was operated in areas with a multi-
year sea-ice cover. 


Tab. 8.1: Settings of ATLAS HYDROMAP CONTROL for operating Parasound 
          during cruise ARK-XXVI/3 (P-SBP Parametric Sub-Bottom 
          Profiling; SBES Single-Beam Echo-Sounder). 

          Used Settings   | Selected Options |  Selected Ranges  
        ————————————————— | ———————————————— | —————————————————
        Mode of Operation |    P-SBP/SBES    |     PHF, SLF    
                          |                  |
            Frequency     |        PHF       |     18.75kHz  
                          |        SLF       |     4.166kHz  
                          |                  |
           Pulselength    |  No. Of Periods  |         2       
                          |      Length      |       0.5ms  
                          |                  |
           Transmission   |   Transmission   |       100%     
           Source Level   |       Power      |
                          |   Transmission   |       159 V
                          |      Voltage     |
                          |                  |
          Beam Steering   |       none       |
                          |                  |
             Mode of      |   Single Pulse   |
          Transmission    |                  |
                          |      Quasi-      |      interval   
                          |    Equidistant   |     400-1200ms  
                          |                  |
           Pulse Type     | Continuous Wave  |
                          |                  |
           Pulse Shape    |    Rectangular   |
                          |                  |
          Receiver Band   |   Output Sample  |      6.1kHz   
              Width       |    Rate (OSR)    |
                          |    Band Width    |       66%  
                          |    (% of OSR)    |
                          |                  |
        Reception Shading |       none       |
                          |                  |
          System Depth    |    Fix Min/Max   |      Maunal   
             Source       |    Dept Limit    |
                          |                  | Other (DWS or HS) 
                          |                  |  Atlas Parastore  
                          |                  |
         Water Velocity   |      C-Mean      |  Manual 1500m/s
                          |      C-Keel      |   System C-keel  
                          |                  |
         Data Recording   |        PHF       |   Full Profile
                          |        SLF       |   Full Profile  
                          |        SGY       |   Full Profile 


Digital data acquisition and storage were switched on in the Barents Sea 
on August 6 at 17:02 UTC, and was switched off after a day of testing 
when Polarstern entered the Russian EEZ on August 7 at 17:54 UTC. After 
the ship has left the Russian EEZ on August 9 in the Nansen Basin the 
system was started again at 09:23 UTC. The system has been switched off 
again from September 14 at 11:16 UTC to September 19 at 06:57 UTC when 
station work was conducted off Zevernaya Zemlya. Data acquisition was 
finally stopped and the system switched off at the Laptev Sea continental 
slope on September 22 at 19:30 UTC when the ship entered the Russian EEZ 
to conduct the last oceanographic transects before leaving the working 
area through Vilkitsky Strait. 

Acquisition included PHF (Primary High Frequency) and SLF (Secondary Low 
Frequency) data during the entire cruise. Both PHF and SLF traces were 
visualized as online profiles on screen. SLF profiles (100 m or 200 m 
depth windows) and online status (120 s intervals) were printed on A4 
pages. For the entire period and simultaneously with sounding six 
different types of data files were stored on hard disc: 

- PHF data in ASD (Atlas Sounding Data) format 

- PHF data in PS3 format 

- SLF data in ASD format 

- SLF data in PS3 (Export format of Parasound data) format 

- SLF data in SGY format 

- Navigation data and general Parasound settings (60s intervals) in 
  ASCII format 

- Auxiliary data about ATLAS PARASTORE 3 settings in ASCII format. 

All ASD data are automatically packed into "cabinet files" by Atlas 
software. The files are named according to date and time of recording 
(containing about ten minutes of acquired data per file). The data have 
been sorted daily into folders according to data type and recording dates 
(0 to 24 hours UTC), copied to the storage PC via LAN and checked for 
completeness and readability (ATLAS PARASTORE-3 in replay mode, 
selectively only). Once checked, the data folders were copied to the 
Polarstern mass storage and to an external hard disc for daily back-ups 
and final transfer into the AWI database after the end of cruise. In 
total 39,092 folders of data with a total volume of 181 GB were 
transferred. 

During the entire period of acquisition, the system was operator 
controlled (watch keeping). Book keeping was carried out including basic 
Parasound system settings, some navigation information, various kinds of 
remarks as well as a low-resolution hand-drawn bathymetry plot with 
preliminary data interpretation of SLF online profiles, which provides an 
overview about echo types and specific findings during the cruise. 

Time windows with data of specific interest (e.g. geological situations 
at or near stations, special observations, key examples for different 
types of facies or stratigraphy) were selected and replayed during the 
cruise using optimal settings of ATLAS PARASTORE-3. The examples shown in 
figures Fig. 8.2 to 8.5 were processed with the SENT program. 

In contrast to ARK-XXVI/3, the system operated in a stable mode 
throughout this expedition. A single system crash was caused by the 
operator at the beginning of the expedition in the Barents Sea. Sea ice 
affected the quality of the data to a variable degree causing noisy 
records with some traces missing. More extensive data loss and a poor 
data quality mainly resulted from heavy ice conditions or slopes at 
submarine highs too steep to return a signal from the seafloor. In a few 
cases when both Parasound and Hydrosweep recorded wrong water depths data 
were lost as well. Usually, the PHF signal allowed identifying the sea 
floor, even on steep slopes or during heavy ice conditions. 


Fig. 8.2: Parasound example from the Amundsen Basin. 

Fig. 8.3: Parasound example from the Lomonosov Ridge 

Fig. 8.4: Parasound example from the Makarov Basin 

Fig. 8.5: Parasound example from the northern Mendeleev Ridge 


Preliminary results 

Eurasian Basin 

The Parasound records from the Nansen and Amundsen Basins along the 60E 
transect are comparable to those obtained during previous Polarstern 
expeditions ARK-VIII/3 (Bergmann, 1996), ARK-XIV/1a (Jokat, 1999), ARK-
XVII/2 (Hatzky, 2008) and ARK-XXII/3 (Schauer, 2008). The sediments are 
acoustically stratified and show a rather regular pattern of sub-parallel 
reflectors (Fig. 8.2). Penetration into the relatively flat-lying sea 
floor was up to 60 m. Few data could be obtained from the Gakkel Ridge 
because slopes were too steep. However, some records show evidence for 
mass flow deposits. Penetration generally decreased towards the Lomonosov 
Ridge, where some v-shaped relatively narrow, shallow incisions (less 
than 10 m) have been recorded in the basin. Further to the east (135 
Р120E off the Laptev Sea) echo character changed from acoustically 
stratified sub-parallel sediments with up to 50 m thickness at the slope 
of Lomonosov Ridge to a rather wavy irregular sediment pattern in the 
deep Amundsen Basin with decreased penetration (less than 30 m), 
considerable changes in thickness of individual units over short 
distances, laterally restricted lens-shaped acoustically transparent 
sediment bodies and v-shaped relatively narrow up to 30 m deep incisions. 
At the Laptev Sea continental slope comparable acoustic reflections have 
been observed, but these changed more frequently over short distances 
than further to the north. 

The variable acoustic character of the sediments reflects strongly 
variable depositional conditions. Sediments may be of pelagic origin 
along the 60°E transect in the basins distal to submarine slopes but 
coring during ARK-VIII/3 revealed 138 the presence of thick turbidites in 
these basins (Fütterer, 1992). Kristoffersen et al. (2004) have mapped a 
submarine fan and a deep-sea channel system in the Amundsen Basin 
extending from the Lincoln Sea off northern Greenland to the deep sea 
plain at the North Pole. The small incisions recorded at the North Pole 
may represent distributary channels of the distal channel system. Thus, 
thick turbidites might have originated at the northern Greenland 
continental slope. Proximal to the Laptev Sea, comparable conditions 
might have prevailed with a substantial supply of sediments from the 
Laptev shelf being transported downslope into the deep sea. The acoustic 
facies at the slope may be additionally influenced by the slowly 
spreading Gakkel Ridge because the cruise track followed more or less the 
axis of the rift. 

Lomonosov Ridge 

The Lomonosov Ridge has been crossed twice at ca. 89N, 115W and 84N, 
150E, respectively. The records are comparable to those obtained during 
ARK.VIII/3 (Bergmann, 1996), ARK-XIV/1a (Jokat, 1999) and ARK-XXII/3 
(Schauer, 2008). Acoustically stratified sediments drape the ridge down 
to 40m depth indicating pelagic sedimentation and absence of glacial 
erosion (Fig. 8.3). The uppermost about 5 m show stronger reflection 
amplitudes. Internal reflectors are hardly visible at the slopes (see 
Fig. 8.3) and usually only the seafloor is reflected in the PHF signal if 
slopes were not too steep. 

Makarov Basin 

The bathymetry of the Makarov Basin is quiet variable because of numerous 
submarine highs that have been crossed along the ships track. The basin 
has been crossed twice at ca. 89-86N, 115-150W and 85-84N, 180-150E. 
Although data quality is particularly poor along the western transect due 
to heavy ice conditions acoustically stratified up to 40-50 m thick 
sediments have been recognized both in the deeper part of the basin and 
on submarine highs suggesting pelagic depositional conditions (Fig. 8.4). 
The uppermost 3 to 4 m depict stronger reflection amplitudes. Thus, the 
acoustic facies is comparable to those recorded during ARK-XIV/1a (Jokat, 
1999) and ARK-XXII/3 (Schauer, 2008). 

Alpha Ridge 

At the junction of the Alpha and Mendeleev Ridge at ca. 140W acoustically 
stratified sediments are replaced by undulating sea floor reflections and 
common side echos. Comparable reflections have been observed parallel 
tracks studied during ARK.XXII/2 (Schauer, 2008) whereas on tracks 
further to the west acoustically stratified sediments have been observed 
during ARK-XIV/1b (Jokat, 1999). The undulating seafloor reflections and 
side echos might be related to a possible extraterrestrial impact 
suggested by Kristoffersen et al. (2008) to explain extensive seabed 
disturbance in the Alpha Ridge regon. 

Northern Mendeleev Ridge 

The acoustic facies on the northern Mendeleev Ridge is somewhat variable 
due to a variable topography consisting mainly of acoustically stratified 
sediments with a penetration of up to 40 m (Fig. 8.5) and subordinate 
undulating sediments with almost absence of sub-parallel reflections. The 
uppermost 2 to 3 m are characterized by stronger reflection amplitudes. 







8.3  Sediment cores 

     Antje Boetius(1), Alex Charkin(2),     1 Alfred-Wegener-Institut 
     Elisabeth Helmke(1), Tina Kollaske(1), 2 POI-FEBRAS, Vladivostok 
     Jens Matthiessen(1), Ann-Katrin        3 Institute for Chemistry 
     Meinhardt(3), Norbert Lensch(1),         and Biology of the Marine 
     Patricia Slabon(1), Mirko Sühs(1),       Environment, Oldenburg
     Hao Zao(1) 


Work at sea 

Near-surface sediments and longer sedimentary sequences were sampled at 
22 stations (Fig. 8.6). Near-surface sediments were collected with a 
giant box corer (GKG, 50 cm x 50 cm x 60 cm) at 6 stations and a 
multicorer (MUC) with 8 tubes (diameter 10cm) at 19 stations. The MUC was 
preferred to the GKG because bottom water and an absolutely undisturbed 
sediment-water interphase was required for sampling the uppermost 
sediment layers at cm intervals for foraminiferal (chapter 8.3.1), for an 
extensive pore water sampling program (chapter 8.3.3), and for benthic 
biological (chapter 8.3.2), biogeochemical (chapter 6), and geochemical 
studies (chapter 5.3). 

After recovery of the MUC the individual tubes were sampled for various 
purposes (Tab. 8.2). Single tubes were cut into 1 cm slices for inorganic 
geochemistry and for archiving. One tube was used on some stations for 
pore water sampling. The uppermost 6 cm of two to three tubes were 
sampled for foraminiferal analysis while a second set of two tubes was 
subsampled for various biological studies. Surface sediments were sampled 
for geochemical, organic geochemical analysis as well as microbiological 
studies. 


Fig. 8.6: Geographic location of bottom sampling stations. Numbers refer 
          to station numbers of ARK-XXVI/3 (PS78). 


Tab. 8.2: List of samples taken from MUC and GKG. 

   Station   | Gear |  A 1   | P W | I G | B F | B 0 |  M  | O G |  G  |  A  |  X
             |      |  R 9   | o a | n e | e o | e - |  i  | r e |  e  |  r  |  -
             |      |  K 9   | r t | o o | n r | n 1 |  c  | g o |  o  |  c  |  r
             |      |  V 1   | e e | r c | t a | t 0 |  r  | a c |  c  |  h  |  a
             |      |  I     |   r | g h | h m | h   |  o  | n h |  h  |  i  |  d
             |      |  I     |     | a e | i i | o   |  b  | i e |  e  |  v  |  i
             |      |  I     |     | n m | c n | s   |  i  | c m |  m  |  e  |  o
             |      |  /     |     | i i |   i |     |  o  |   i |  i  |     |  g
             |      |  3     |     | c s |   f |     |  l  |   s |  s  |     |  r
             |      |        |     |   t |   e |     |  o  |   t |  t  |     |  a
             |      |        |     |   r |   r |     |  g  |   r |  r  |     |  p
             |      |        |     |   y |   s |     |  y  |   y |  y  |     |  h
             |      |        |     |     |     |     |     |     |     |     |  y 
———————————  | ———— | —————— | ——— | ——— | ——— | ——— | ——— | ——— | ——— | ——— | ———
PS78/201-7   | MUC  |        |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/204-4   | MUC  | PS2163 |     |     |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/205-5   | MUC  | PS2164 |     |     |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/206-2   | MUC  | PS2165 |  X  |  X  |  X  |  X  |     |  X  |  X  |  X  |  
PS78/206-4   | GKG  | PS2165 |     |     |  X  |     |     |     |     |  X  |  X
PS78/207-4   | GKG  |              sponge mat, sampling only for biology 
PS78/208-1   | MUC  | PS2166 |  X  |  X  |  X  |  X  |     |  X  |  X  |  X  |  
PS78/211-1   | MUC  | PS2170 |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/217-1   | MUC  | PS2190 |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/220-1   | MUC  |        |  X  |  X  |  X  |  X  |     |  X  |  X  |  X  | 
PS78/221-3   | MUC  |        |     |     |  X  |  X  |     |  X  |  X  |  X  | 
PS78/221-5   | GKG  |        |     |     |  X  |     |     |     |     |  X  |  X
PS78/225-4   | MUC  |        |  X  |  X  |  X  |  X  |  X  |  X  |  X  |     |  
PS78/231-1   | MUC  |        |     |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/231-3   | GKG  |        |     |     |  X  |     |     |     |     |  X  |  X
PS78/237-1   | MUC  |        |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/238-2   | GKG  |        |     |     |  X  |     |     |  X  |  X  |  X  |  X
PS78/241-3   | GKG  |        |     |     |  X  |     |     |  X  |  X  |  X  |  X
PS78/248-4/5 | MUC  |        |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/275-1   | MUC  |        |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/276-6   | MUC  |        |     |     |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/277-2   | MUC  |        |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/280-6   | MUC  |        |  X  |  X  |  X  |  X  |  X  |  X  |  X  |     |  
PS78/283-2   | MUC  |        |     |     |  X  |  X  |  X  |  X  |  X  |  X  |  
PS78/285-6   | MUC  |        |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  X  |  
 

The GKG was successfully used at 5 stations but at station 207 only 
sponge mats and rocks (basalts?) were recovered. Recovery ranged from 30 
to 40 cm. After the surface was photographed and described two archive 
tubes (diameter 12 cm) were pushed into the sediment. Surface sediments 
were then sampled for sedimentological, organic geochemical and 
micropaleontological analysis. After opening the front side of the GKG 
the profile was photographed and then sampled continuously for x-
radiography and archive purposes (2-3 boxes). MUC and GKG samples were 
frozen (-20 to -80°C) or stored at 4°C. 

Long sediment cores were obtained at 8 stations with a gravity corer (SL) 
of 5 or 10 m length and 12 cm diameter with a penetration weight of 1.5 
t. Prior to opening, some sediment cores were sampled for pore water in a 
cool room at 4°C (chapter 8.3.3.). After core sections have warmed to 
room temperature for at least 24 hours, the sediment cores were logged 
using the Multi-Sensor-Core-Logger (MSCL). Then, cores were opened, 
photographed and described, and sediment slices for X-ray photography and 
samples for determination of water content were taken. Colour 
spectrometry and point susceptibility measurements were conducted on 
split core halves. Selected x-ray photographs were analysed for 
sedimentary structures and content of coarse-ice rafted debris (IRD) 
larger than 2 mm. Discrete sampling was only done for inorganic 
geochemistry on a core PS78/248. All sediment cores were stored onboard 
in a cool container at 4°C and were transferred to the Polarstern core 
repository in Bremerhaven after the expedition. 

Shipboard analyses performed on the sediment cores are described in the 
following chapters but standard methods such as photography, x-ray 
radiography, counts of gravel-sized particles) are not included. 
Descriptions of these methods may be found in Jokat (2009). 

All shipboard data (sediment core descriptions, photographs, digitized 
negatives of x-ray radiographs, physical property data, colour 
spectrophotometry, counts of gravel-sized particles) will be stored in 
the Pangaea database. 


8.3.1  Benthic foraminifera communities of the Amerasian and Eurasian 
       Basins and the trace metal ratios recorded in calcareous tests of 
       benthic foraminifera 

       Mirko Sühs                          Alfred-Wegener-Institut 
       not on board: Jutta Wollenburg, 

Objectives The major goal was to supplement our existing data set on 
benthic foraminifer distribution in the Arctic Ocean. Furthermore, we 
started a new project to evaluate the environmental controls of trace 
metal ratios recorded in calcareous shells of benthic foraminifers. 

Work at sea 

For this purpose, short sediment cores were collected at 24 stations in 
the Eurasian and Amerasian Basins from 1600 to 4100 m water depth 
(Fig.8.6; Tab. 8.2). Two to three multicorer tubes from each coring site 
were sliced in 1-cm steps from the surface to 6 centimeters sub-bottom 
depth. The subsamples were transferred into plastic bottles and mixed 
with an equivalent volume of ethanol-Rose Bengal mixture (1g Rose 
Bengal/l ethanol). Rose Bengal is a protein stain and allows in 
subsequent faunal analyses to discriminate living (protoplasm bearing) 
from empty shells. 

Expected results 

In the next months we will analyse the biocoenoses and taphoceonoses, 
carry out trace metal analyses on shells of key foraminifers and 
correlate the results with the environmental conditions at the sites. 
Since the incorporation of trace metals is influenced by temperature, pH 
and the carbonate ion system, these environmental parameters are of 
particular importance. Since some stations have been already sampled 20 
years ago, comparative trace metal and faunal investigations will 
identify effects of the most recent and prevailing environmental change 
in this highly sensitive area. 


8.3.2  Benthic processes 

       Antje Boetius                    Alfred-Wegener-Institut 


Objectives 

MUC subsamples were taken to analyze chlorophyll pigment concentrations 
as a proxy for marine detritus sedimentation, bacterial cell counts and 
total phospholipid concentration, as well as potential hydrolytic 
enzymatic activities and bacterial diversity. 

Work at sea 

At every site, 2 cores were taken (Tab. 8.2). One was sliced every cm for 
the first 10 cm and preserved by deep-freezing for different molecular 
methods such as the DNA community fingerprinting technique ARISA. The 
other one was sampled by cut-off syringes for cell counts, lipid 
analyses, and other biogeochemical parameters. For cell counts, 1mL 
sediment was added to 2% 9mL formalin-sea water solution, and preserved 
at 4°C. 

Expected results 

These samples will provide an overview on microbial benthic activities at 
water depths of 1,500-5,500 m, in areas, which were last sampled 10-20 
years ago. 


8.3.3  Inorganic geochemistry of Arctic Ocean sediments 

       Ann-Katrin Meinhardt          Institute for Chemistry and Biology 
                                     of the Marine Environment, Oldenburg  

Objectives  

The goal of the geochemical program was a detailed investigation of 
Arctic Ocean sediments and pore waters. The main focus will be to 
investigate the formation mechanism and geochemical expression of 
repetitively occurring brown coloured 143 sediment layers ("Manganese 
cycles"). In Arctic Ocean sediments distinct dark brown intervals, which 
are rich in Mn and Fe compared to other hemipelagic sediments, alternate 
with light olive/yellowish brown intervals, which are comparably poor in 
these elements. There are different explanations for the formation 
mechanism of these colour cycles. Primary sources of Mn and Fe in the 
Arctic Ocean are the circum-Arctic rivers, which drain extensive peat 
bogs rich in both, Mn and Fe. The input of metals to the deeper ocean 
basins is controlled by climatic features, i.e., higher riverine input 
during warmer conditions and lower input during colder conditions, or 
changes in ventilation of the bottom waters. Another explanation for the 
cyclicity may be diagenetic overprinting after deposition. During organic 
matter degradation, microbially mediated dissolution of metal (oxyhydr) 
oxides may occur in the absence of free oxygen under suboxic to anoxic 
conditions. The reduced metal species are then liberated to the pore 
water. Upon diffusion to the oxic/suboxic boundary, the reduced metal 
species may again precipitate and form a new sedimentary Mn/Fe peak. 
Multiple dark brown Mn- and Fe-rich intervals may be formed in this way 
after deposition. Our work focuses at a combination of both, sediment and 
pore water analyses to obtain information about the importance of organic 
matter degradation in Arctic Ocean sediments and the diagenetic mobility 
of metals like Mn and Fe. 


Work at sea 

Sampling of pore water was performed at 18 stations (Tab. 8.3) shortly 
after sediment recovery. The sediment cores (MUC or SL) were transported 
into the 4°C laboratory, where the pore waters were sampled by the rhizon 
technique. Pore water sampling of giant box corers was not performed due 
to problems during ARK-XXIII/3 (Jokat, 2009). A rhizon is a polymer 
filter with 0.1 m pore size, which is attached to a PE/PVC tube with a 
luer lock. The MUC tubes were prepared with pre-drilled 3.8 mm holes in 1 
cm resolution, which were taped during the coring process. In the cooling 
laboratory, the rhizons were stuck into the tube at variable resolution 
(~1 to 5 cm). A syringe was attached to every rhizon and vacuum was 
applied with the help of a spacer (Fig. 8.7). Pore waters of the SL were 
sampled in a similar way by drilling holes into the liner at ~20 cm 
resolution and inserting the rhizons (Fig. 8.8). Variable amounts of pore 
water were retrieved, mostly ~10 ml, depending on sediment features like 
porosity and sampling time. After sampling, the rhizons were removed, the 
cores were sealed, and the pore water was filled in PP-tubes. Several 
fractions were obtained (1. untreated, for the determination of labile 
components and nutrients; 2. acidified, for the determination of metals 
after the cruise; 3. oxygenated [for reactive Mn, see below]) and stored 
at 4°C. Rhizons were cleaned with 10% HCl and Milli-Q-Water for re-use. 

Sediment samples of the MUC cores were taken at 1 cm resolution with a 
plastic spatula and stored in plastic bags. Sediment samples of a GC 
(PS78/248-6) were taken with plastic spatula at variable resolution, 
depending on discernible sediment properties, and stored in plastic bags. 

For the determination of reactive Mn, a fraction of the pore water was 
left in the syringe and allowed to oxidise for ~48 hours. After this time 
the pore water was filled in PP-tubes with a syringe filter and was 
acidified with HNO3. 

Directly after dividing the pore water into the different fractions, 
analyses of ammonium and total alkalinity were performed. Both parameters 
were determined via photometric methods using a microtiter plate reader, 
which only consumes less than 0.5 ml per sample. The preserved pore water 
fractions will be analysed onshore for several dissolved ions and metals 
(e.g. nitrate, phosphate, manganese, iron and other main and trace 
elements) via photometric methods, ICP-OES and ICP-MS. The sediment 
samples will be freeze-dried, ground and analysed for major and minor 
elements and bulk parameters using X-Ray Fluorescence, coulometry, 
combustion analyses, ICP-OES and ICP-MS. 


Tab. 8.3: List of pore water samples, sediment samples and measured 
          parameters on board 

 Station    Gear  Sediment  Alkalinity  Ammonium  Acidified  Reactive
                                                    split    Mn split  
——————————  ————  ————————  ——————————  ————————  —————————  ————————
PS78/201-7  MUC      X          X           X         X          
PS78/206-2  MUC      X          X           X         X          
PS78/206-3  GC                  X           X         X          X  
PS78/208-1  MUC      X          X           X         X          
PS78/211-1  MUC      X          X           X         X          
PS78/217-1  MUC      X          X           X         X          
PS78/220-6  MUC      X          X           X         X          
PS78/220-7  GC                  X           X         X          X  
PS78/225-4  MUC      X          X           X         X          
PS78/231-2  MUC      X                                  
PS78/231-2  GC                  X           X         X          X  
PS78/237-1  MUC      X          X           X         X          
PS78/237-3  GC                  X           X         X          X  
PS78/248-4  MUC      X          X           X         X          
PS78/248-6  GC       X          X           X         X          X  
PS78/275-1  MUC      X          X           X         X          
PS78/277-2  MUC      X          X           X         X          
PS78/280-6  MUC      X          X           X         X          
PS78/285-6  MUC      X          X           X         X          


Fig. 8.7: Pore water sampling of a MUC 

Fig. 8.8: Pore water sampling of GC segments 

Fig. 8.9: Pore water profile of sediment core PS78/248-6 (SL) 



Preliminary results 

In most of the cores, pore water ammonium values are low, ranging close 
to the detection limit of the method and ~10 M, and show no trends with 
depth. One exception is core PS78/248-6 (Fig. 8.9, Lomonosov Ridge) with 
increasing values from ~470 cm core depth up to ~44 M at 585 cm. 

Both ammonium and inorganic carbon species (=alkalinity) are metabolites 
of microorganisms. Increasing ammonium values with depth are indicative 
for the increasing degradation of organic matter in the sediment. But 
compared to other marine settings, the observed values are rather low. 
Alkalinity values of all cores show little variability with depth and 
range mostly between 2 and 3 mM (Fig. 8.9) 

In the reactive Mn experiment, the fraction that was allowed to oxidise 
showed no precipitation of solid, oxidised Mn. This visual observation 
needs to be tested by quantitative Mn measurements of both fractions. 

These very first results illustrate the general low productivity in the 
Arctic Ocean. In one of the sediment cores (PS78/248-6) the increase of 
ammonium with depth indicates that diagenetic processes may occur deeper 
in the sediment. Further analyses of other parameters are necessary for a 
comprehensive study. 


8.3.4  Non-destructive sediment core measurements 

Non destructive measurements at cm intervals have been performed on whole 
cores and split core halves to provide initial information on the 
physical properties of the sediments and the variability of sedimentary 
colours. 

In combination with sediment core descriptions and x-ray radiographs they 
allow a first interpretation of the paleoenvironment and enable to more 
precisely select discrete samples for detailed analysis. Furthermore, 
these parameters may be used to correlate distinct sedimentary unit over 
long distances. 


8.3.5  Multi-sensor core logging 

       Jens Matthiessen, Tina Kollaske      Alfred-Wegener-Institut 

Measurements in the ship laboratory included non-destructive, continuous 
determinations of wet bulk density (wbd), P-wave velocity (vp) and 
magnetic susceptibility (ms) at 10 mm intervals on all cores (GKG, SL) 
obtained during the cruise. The Multi Sensor Core Logger (MSCL14n, GEOTEK 
Ltd., UK) was used to measure core temperature, core diameter, P-wave 
travel time, gamma-ray attenuation and ms. The principle of logging cores 
is described in more detail in previous Polarstern cruise reports (e.g. 
Niessen et al. in Jokat, 2009). The orientation of the P-wave and gamma 
sensors was horizontal. Gravity cores were measured in coring liners 
including end caps. Details of measurements, calculations and technical 
specifications of the used MSCL may be found in Niessen et al. (Jokat, 
2009). Prior to measuring a sediment core, a standard core consisting of 
different proportions of aluminium and water as described in Best & Gunn 
(1999) has been logged for calculation of WBD. 

To obtain a higher resolution at cm intervals, ms was measured on split 
cores with a Multi Sensor Core Logger XZ (MSCL-XZ, GEOTEK Ltd., UK) using 
a Bartington MS2E point sensor. Visual inspection of loop and point 
sensor data showed a good correlation (possible causes of offsets have 
been discussed by Niessen et al. in Jokat, 2009). All data will be stored 
as a function of core depth in the databank PANGAEA. 


8.3.6  Spectral photometry 

       Jens Matthiessen                     Alfred-Wegener-Institut 

During expedition ARK-XXVI/3 a Multi Sensor Core Logger XZ (MSCL-XZ, 
GEOTEK Ltd., UK) and a attached Minolta colour spectrophotometer CM-2600d 
was used to measure reflectance spectra of gravity cores. Reflectance 
spectra were collected in 39 spectral bands between 360 and 740 nm in 10-
nm spectral bands with 10 mm aperture. Measurement spacing was generally 
set to 1 cm. The split core surfaces of the archive halves were covered 
by a standard film to protect the spectrophotometer. 

Output files are the greyscale reflectance, the chroma, hue and value of 
the Munsell Colour Chart, the CIE XYZ colour space (defined according to 
the RGB colours, CIE 1931), the CIE L*a*b* colour space (referred to as 
CIELAB space, Commission Internationale de lclairage L*a*b colour space 
1976) and the percentage values of the spectra in 10 nm steps. Data 
output are Tab-delimited ASCII (.csv files) that were converted into 
Excel files (.xls) and edited for each sediment core separately in Excel 
sheets. Obvious outliers e.g. due to uneven core surfaces or holes as 
noted while measuring were deleted from the data set. After final editing 
all data will be deposited separately for each sediment core under the 
respective station and cast number in the data bank PANGAEA. 

Preliminary results from sediment core analysis 

Sediment surfaces 

The relatively few sediment surfaces obtained with the GKG do not allow 
to distinguish regional trends in the distribution of sedimentary facies. 
Grain size composition of the generally brownish sediments is quite 
variable ranging from clays to sandy silty clays but most surfaces are 
relatively coarse-grained. This might be due to the selection of sites on 
elevated submarine structure where bottom currents might have winnowed 
the fine fraction. Gravel (up to 2 - 3 cm) is common on most surfaces. 
Among the biogenic components corroded shells and shell fragments are 
common, while larger calcareous foraminifers were rarely observed on 
surfaces. 

A common feature is the occurrence of sponges and sponge spicules at some 
locations both in GKG and MUC. In particular at the Karasik Seamount 
(Gakkel Ridge), sponges and spicules form dense mats in the uppermost 
centimeters at stations 205, 206, and 207. At station 207 on the top of 
the seamount sponge mats cover basaltic? rocks while at the other 
stations they overlain siliciclastic sediments. Additionally, at station 
248 on the Lomonosov Ridge sponges were recovered with a multi corer. 

Sediment cores 

All sediment cores are characterized by some colour variation with 
brownish layers alternating with light brownish/olive layers. Except for 
SL 206 from Gakkel Ridge that has a pronounced lithological variability 
throughout the core the lithofacies is more variable in the upper part of 
the sediment cores with distinct alternations of coarse-grained layers, 
sometimes comprising gravel-sized ice-rafted debris (IRD), and fine-
grained layers. The lower part is relatively fine-grained composed of 
silty clays to clayey silts with few thin intervals of coarser material. 
Based on this pronounced change in lithofacies, the lithology of the new 
sediment cores may be subdivided into two units (e.g. PS78/231-2; Fig. 
8.10) as it has been done in cores collected during ARK-XXIII/3 across 
the southern Mendeleev Ridge (Stein et al., 2010b). Additionally, 
sediment cores at the Alpha Ridge may be correlated by distinct physical 
property events (Sellén et al., 2010). 

Prominent sedimentary units may form key lithostratigraphic marker beds 
to correlate sediment cores over longer distances. The sediment cores GC 
206, 220, 221, and 248 from the Gakkel and Lomonosov Ridges exhibit a 
characteristic dark grayish layer that may correspond to a unique 
lithostratigraphic horizon independently dated in a number of sediment 
cores to late MIS 4 (e.g. Sellén et al., 2008). In the Amerasian Basin, 
detrital carbonate-rich layers in Unit I of GC 231, 237, 238 and 241 
allow a tentative correlation to well-known key lithostratigraphic marker 
beds (white and pink-white layers) recognized in numerous sediment cores 
located on the Alpha and Mendeleev Ridges (e.g. Clark et al., 1980; 
Minicucci & Clark, 1983; Mudie & Blasco, 1985; Stein et al., 2010a,b; 
Matthiessen et al., 2010; Fig. 8.10) but their chronostratigraphic 
position has not been resolved yet. In sediment cores from the Alpha 
Ridge the eye-catching pinkish component in these layers is apparently 
absent (Clark et al., 1980; Jokat, 1999; Schauer, 2008) making assignment 
to one of the markers beds difficult. Nevertheless, all these layers are 
confined to Unit I. 

This unit can be further subdivided according to the standard 
lithostratigraphy established by Clark et al., (1980) for the Alpha and 
Mendeleev Ridges but individual units may vary in thickness and/or may be 
even absent. The coarse-grained lithological units of this 
lithostratigraphy (Fig.8.10, marked by letters in the IRD column) may be 
potentially useful for supra-regional correlation (compare with IRD 
records in Stein et al., 2010b). 

Correlating the upper sedimentary units in GKG and MUC from the western 
Alpha Ridge to the southern Mendeleev Ridge clearly show an increase in 
thickness of units to the south (Fig. 8.11) as has been suggested already 
from computing average sedimentation rates (Stein et al., 2010a,b). The 
upper brown layers are clearly separated at the southern Mendeleev Ridge 
by a light brown/olive unit that thins out to the north. The uppermost 
white layer W3 decreases in thickness as well and is hardly visible at 
the western Alpha Ridge. This layer is also not visible in sediment core 
GC221 from the Lomonosov Ridge. 

Due to its lithological uniformity Unit II may be primarily subdivided 
based on colour variations (Fig. 8.10) according to Stein et al. (2010b; 
sediment lightness, a* and b* values; units A, A1 etc.) and these 
distinct changes may be traced along the Mendeleev and Alpha Ridges over 
long distances. 


Fig. 8.10: Lithostratigraphic units, magnetic susceptibility, IRD 
           content, L* lightness, a* red-green colour space, and b* 
           yellow blue colour space of sediment core PS78/231-2. 
           Potential tie points in physical properties are marked in the 
           magnetic susceptibility record (AR1-AR5, according to Sellén 
           et al., 2010). Detrital carbonate-rich layers are marked with 
           red lines. Black lines indicate distinct steps in colour data 
           (see Stein et al. 2010b, Fig. 11). 

Fig. 8.11: Tentative correlation of lithological marker beds in near-
           surface sediments from Lomonosov Ridge (PS78/221-5, PS78/248-
           5), Alpha Ridge (PS78/231-3) and Mendeleev Ridge (PS78/241-4, 
           PS78/237-1, PS78/238-2) based on identification of brown beds 
           B1 and B2, and white bed W3 in box core PS72/399-3 by Stein et 
           al. (2010b). For locations of cores see Fig. 8.6. 



References 

ATLAS Hydrographic (2007): ATLAS HYDROMAP CONTROL Operator Manual. Doc.-
    Id.: ED1060 G 312, File: ED-1060-G-312_ V5-0. Edition: 04.2007. ATLAS 
    HYDROGRAPHIC, Bremen, Germany. 

ATLAS Hydrographic (2007): ATLAS PARASTORE-3 Operator Manual. Doc. Id.: 
    ED 6006 G 212:/ Version: 4.0 / Edition: 05/2007. ATLAS HYDROGRAPHIC,  
    Bremen, Germany. 

Bergmann, U. (1996): Interpretation digitaler Parasound 
    Echolotaufzeichnungen im stlichen Arktischen Ozean auf der Grundlage 
    physikalischer Sedimenteigenschaften. Reports on Polar Research, 
    Dissertation, Alfred Wegener Institute for Polar and Marine Research, 
    Bremerhaven, 83, 164 pp. 

Best, A. I., Gunn, D.E. (1999) Calibration of marine sediment core 
    loggers for quantitative acoustic impedance studies. Marine Geology, 
    160, 137-146. 

Clark, D.L., Whitman, R.R., Morgan, K.A. & Mackey, S.D. (1980): 
    Stratigraphy and glacial-marine sediments of the Amerasian Basin, 
    Central Arctic Ocean. Geological Society of America, Special Papers, 
    181: 57p. 

Fütterer, D.K. (1992, ed.): The expedition ARK-VIII/3 of RV "Polarstern" 
    1991. Reports on Polarf Research, 1992. 107: p. 267. 

Hatzky, J. (2008): Analyse von Bathymetrie und akustischer Rkstreuung 
    verschiedener Fchersonar- und Sedimentecholot-Systeme zur 
    Charakterisierung und Klassifizierung des Meeresbodens am Gakkel-
    Rcken, Arktischer Ozean. Dissertation, Alfred Wegener Institute for 
    Polar and Marine Research, Bremerhaven, 231pp. 

Jakobsson, M., R. Macnab, L. Mayer, R. Anderson, M. Edwards, J. Hatzky, 
    H. W. Schenke, and P. Johnson (2008), An improved bathymetric 
    portrayal of the Arctic Ocean: Implications for ocean modeling and 
    geological, geophysical and oceanographic analyses, Geophysical 
    Research Letters, doi: 10.1029/2008gl033520. 

Jokat, W. (1999): Arctic98: The Expedition ARKTIS-XIV/1a of Research 
    Vessel Polarstern in 1998, Reports on Polar and Marine Research, 
    Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, 
    308, 159 pp. Jokat; W. (2009): The Expedition of the Research Vessel 
    "Polarstern" to the Arctic in 2008 (ARK-XXIII/3). Reports on Polar 
    and Marine Research, Alfred Wegener Institute for Polar and Marine 
    Research, Bremerhaven, 597, 221 pp. 

Klages M. & Thiede J. (2011).- The expeditions ARKTIS-XXII/1a-c of the 
    research vessel "Polarstern" in 2007/ Ed. by Michael Klages and Jn 
    Thiede with contributions of the participants. Reports on Polar and 
    Marine Research, 627, 194pp. 

Kristoffersen, Y., Hall, J.K., Hunkins, K. Ardai, J., Coakley, B.J., 
    Hopper, J.R. & Healy 2005 seismic team (2008). Extensive local seabed 
    disturbance, erosion and mass wasting on Alpha Ridge, Central Arctic 
    Ocean: possible evidence for an extra-terrestrial impact? Norwegian 
    Journal of Geology 88: 313-320. 

Kristoffersen, Y., M. Y. Sorokin, Jokat, W & Svendsen, O. (2004). A 
    submarine fan in the Amundsen Basin, Arctic Ocean. Marine Geology 
    204: 317-324. 

Macke A. (2009): The Expedition of the Research Vessel Polarstern to the 
    Antarctic in 2008 (ANT-XXIV/4), Reports on Polar and Marine Research, 
    Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, 
    591, 64 pp. 

Matthiessen, J., Niessen, F., Stein, R. and Naafs, B.D. (2010): 
    Pleistocene glacimarine sedimentary environments at the Eastern 
    Mendeleev Ridge, Arctic Ocean. Polarforschung 79: 123-137. 

Minicucci, D.A. & Clark, D.L. (1983): A late Cenozoic stratigraphy for 
    glacial-marine sediments of the eastern Alpha Cordillera, Central 
    Arctic Ocean.- In: B.F. Molnia (Ed.), Glacial-marine sedimentation, 
    331-365. New York, London: Plenum Press. 

Mudie, P.J. & Blasco, S.M. (1985): Lithostratigraphy of the Cesar cores.- 
    In: H.R. Jackson, P.J. Mudie & S.M. Blasco (Eds.), Initial geological 
    report on CESAR -the Canadian expedition to study the Alpha Ridge, 
    Arctic Ocean, Geological Survey of Canada Paper, 59-99. 

Schauer, U. (2008): The Expedition ARKTIS-XXII/2 of the Research Vessel 
    Polarstern in 2007, Reports on Polar and Marine Research, Alfred 
    Wegener Institute for Polar and Marine Research, Bremerhaven, 579, 
    264 pp. 

Schiel, S. (2009:) The Expedition of the Research Vessel Polarstern to 
    the Antarctic in 2007 (ANT-XXIV/1), Reports on Polar and Marine 
    Research, Alfred Wegener Institute for Polar and Marine Research, 
    Bremerhaven, 592, 114 pp. 

Sellén, E., Jakobsson, M. & Backman, J. (2008): Sedimentary regimes in 
    Arctic's Amerasian and Eurasian Basins: Clues to differences in 
    sedimentation rates. Global and Planetary Change, 61: 275-284. 

Sellén, E., M. O'Regan & M. Jakobsson (2010): Spatial and temporal Arctic 
    Ocean depositional regimes: a key to the evolution of ice drift and 
    current patterns. Quaternary Science Reviews, 29: 3644-3664. 

Stein, R., Matthiessen, J., Niessen, F. (2010a): Re-coring of T3 Island 
    key core FL-224 (Nautilus Basin, Arctic Ocean): sediment 
    characteristics and stratigraphic framework. Polarforschung, 79: 81-
    96. Stein, R., Matthiessen, J., Niessen, F., Krylov, A., Nam, S., 
    Bazhenova, E. (2010b): Towards a better (litho-) stratigraphy and 
    reconstruction of Quaternary paleoenvironment in the Amerasian Basin 
    (Arctic Ocean). Polarforschung 79: 97-121. 













APPENDIX 

A.1  Participating Institutions 

A.2  Cruise Participants 

A.3  Ship's Crew 

A.4  Station list 




A.1  BETEIlIGTE INSTITUTE / PARTICIPATING INSTITUTES 

Adresse/Address 

AWI                       Alfred-Wegener-Institut für Polar- und 
                          Meeresforschung in der 
                          Helmholtz-Gemeinschaft 
                          Am Handelshafen 12 
                          27570 Bremerhaven/Germany 

DU                        Duke University Durham 
                          Division of Earth and Ocean Sciences 
                          Old Chemistry Bldg. NC 27708, USA 

DWD                       Deutscher Wetterdienst 
                          Geschftsbereich Wettervorhersage 
                          Seeschifffahrtsberatung 
                          Bernhard Nocht Str. 76 
                          20359 Hamburg/Germany 

FIMR                      Finnish Institute of Marine Research 
                          Erik Palmnin aukio 1, P.O. Box 2, 00561 
                          Helsinki/Finnland 

HeliService               HeliService International GmbH, Deutschland 
                          Am Luneort 15 
                          27572 Bremerhaven/Germany 

ICBM                      Institute for Chemistry and Biology of the 
                          Marine Environment Microbiogeochemistry 
                          Carl von Ossietzky University Oldenburg 
                          P.O. Box 2503 
                          26111 Oldenburg/Germany 

LSCE                      Laboratoire des Sciences du Climat et de 
                          l'Environnement , France 
                          Unit mixte CNRS-CEA-UVSQ 
                          Orme des Merisiers, Bât. 701 
                          91191 Gif sur Yvette Cedex/France 

OPTIMARE                  OPTIMARE Sensorsysteme AG 
                          Am Luneort 15a, 
                          27572 Bremerhaven/Germany 

POI                       FEBRAS Pacific Oceanological Institute - Far 
                          Eastern Branch of Russian Academy of 
                          Sciences/Russia 
                          POI FEBRAS, 43 Baltic street Vladivostok 
                          690041/Russia 

RSMAS                     Rosenstiel School of Marine and Atmospheric 
                          Sciences , USA 
                          Division of Marine and Atmospheric 
                          Chemistry, RSMAS/MAC, 
                          University of Miami 4600 Rickenbacker 
                          Causeway Miami, FL 33149/USA 

SIO                       P.P. Shirshov Institute of Oceanology 
                          Russian Academy of Science 
                          36 Nachimovsky prospect, 
                          Moscow, 117851/Russia 

UAF                       University of Alaska Fairbanks 
                          120 OԎeill, P.O. Box 757220, 
                          Fairbanks, AK 99775-7220/USA 

UGot                      University of Gothenburg 
                          Department of Chemistry, SE-412 96 
                          Gothenburg/Sweden 




A.2 FAHRTTEILNEHMER / PARTICIPANTS 

Name/ Name        Vorname/     Institut/     Beruf/Profession  
                  First Name   Institute
————————————————  ———————————  ————————————  ——————————————————————————
Allhusen          Erika        AWI           Technician Biogeochemistry  
Boetius           Antje        AWI           Biologist  
Boissard          Christophe   LSCE          Biologist  
Brauer            Jens         HeliService   Pilot  
Burau             Claudia      AWI           Biologist  
Cassar            Nicolas      DU            Chemist  
Charkin           Alexander    POI           Chemist  
Cherkasheva       Alexandra    AWI           Biologist  
Damm              Ellen        AWI           Chemist  
Dieckmann         Gerhard      AWI           Biologist  
Ericson           Ylva         UGot          Chemist  
Ershova           Elizabeth    UAF           Biologist  
Fernández-Méndez  Mar          AWI/MPI       Biologist  
Galfond           Ben          RSMAS         Chemist  
Hänselmann        Kristin      AWI           Biologist  
Heckmann          Hans         HeliService   Pilot  
Helmke            Elisabeth    AWI           Biologist  
Hendricks         Stefan       AWI           Scientist, sea ice physics  
Hirche            Hans-Jügen   AWI           Biologist  
Hopcroft          Russ         UAF           Biologist  
Hoppmann          Mario        AWI           Physicist  
Hunkeler          Priska       AWI           Student, sea ice physics  
Katlein           Christian    AWI           Student, sea ice physics  
Kilias            Estelle      AWI           Biologist  
Kirschenmann      Eva          AWI           Student, Biogeochemistry  
Kollaske          Tina         AWI           Student, geology  
Kosobokova        Ksenia       SIO           Biologist  
Lensch            Norbert      AWI           Technician Geology  
Ludwichowski      Kai-Uwe      AWI           Chemist  
Matthiessen       Jens         AWI           Scientist, geology  
Meinhardt         Ann-Katrin   ICBM          Student, geology  
Mlendorf          Carsten      HeliService   Mechanic  
Nicolaus          Marcel       AWI           Scientist, sea ice physics  
Peeken            Ilka         AWI           Biologist  
Pisarev           Sergey       SIO           Oceanographer  
Rabe              Benjamin     AWI           Oceanographer 
Ricker            Robert       AWI           Student, sea ice physics
Rentsch           Harald       DWD           Meteorologist 
Rudels            Bert         FIMR          Oceanographer 
Rutgers vd Loeff  Michiel      AWI           Chemist  
Schauer           Ursula       AWI           Chief scientist  
Scholz            Daniel       AWI           Student, chemistry
Serdeczny         Olivia       AWI           Technician, biology
Slabon            Patricia     AWI           Student, bathymetry
Sonnabend         Hartmut      DWD           Meteorol. Technician  
Sühs              Mirko        AWI           Student, geology
Sumata            Hiroshi      AWI           Oceanographer 
Ulfsbo            Adam         UGot          Chemist  
Vaupel            Lars         HeliService   Pilot 
Waddington        Ian          UAF           Technician oceanography
Wischnewski       Laura        AWI           Biologist 
Wisotzki          Andreas      AWI           Technician oceanography
Zenk              Oliver       Optimare/AWI  Technician oceanography
Zou               Hao          AWI           Geologist  
    





A.3  SHIP'S CREW 

                   Name                   Rank 
                   —————————————————————  —————————
                   Schwarze, Stefan       Master 
                   Grundmann, Uwe         1st Offc. 
                   Krohn, Gnter           Ch. Eng. 
                   Gumtow, Philipp        2nd Offc. 
                   Lauber, Felix          2nd Offc. 
                   Rackete, Carola        3rd Offc. 
                   Rudde-Teufel, Claus    Doctor 
                   Hecht, Andreas         R.Offc. 
                   Minzlaff, Hans-Ulrich  2nd Eng. 
                   Sümnicht, Stefan       2nd Eng. 
                   Holst, Wolfgang        3rd Eng. 
                   Scholz, Manfred        ElecEng. 
                   Dimmler, Werner        ELO 
                   Himmel, Frank          ELO 
                   Muhle, Helmut          ELO 
                   Nasis, Ilias           ELO 
                   Loidl, Reiner          Boatsw. 
                   Reise, Lutz            Carpenter 
                   Bäcker, Andreas        A.B. 
                   Brickmann, Peter       A.B. 
                   Guse, Hartmut          A.B. 
                   Hagemann, Manfred      A.B. 
                   Scheel, Sebastian      A.B. 
                   Schmidt, Uwe           A.B. 
                   Wende, Uwe             A.B. 
                   Winkler, Michael       A.B. 
                   Preußner, Jörg         Storek. 
                   Elsner, Klaus          Mot-man 
                   Pinske, Lutz           Mot-man 
                   Schütt, Norbert        Mot-man 
                   Teichert, Uwe          Mot-man 
                   Voy, Bernd             Mot-man 
                   Müller-Homburg, R.-D   Cook 
                   Martens, Michael       Cooksmate 
                   Silinski, Frank        Cooksmate 
                   Czyborra, Bärbel       1.Stwdess 
                   Wöckener, Martina      Stwdss/Kr 
                   Kraft, Henry           2.Steward 
                   Möller, Wolfgang       2.Steward 
                   Silinski, Carmen       2.Stwdess 
                   Streit, Christina      2.Stwdess 
                   Sun, Yong Sheng        2.Steward 
                   Yu, Kwolk Yuen         Laundrym. 







A.4  STATIONSLISTE /STATION LIST PS78 

     See Data Files


Gear Abbreviations: 

CTD/RO   Conductivity/Temperature/Depth System and Rosette Water Sampler  
MN       Multinet  
Bongo    Bong  
Cal      Calibration  
RAMSES   RAMSES-Spectrometer  
MOR      Mooring deployment/recovery  
ROV      Remote Operating Vehicle  
ICE      Ice station  
MUWS     Multiple Water Sampler  
MUC      Multicorer  
GF PUMP  Grundfoss Pump  
XCTD     expendable CTD  
GC       Gravity Corer  
BC       Box Corer  

Die "Berichte zur Polar-und Meeresforschung" (ISSN 1866-3192) werden 
beginnend mit dem Heft Nr. 569 (2008) als Open-Access-Publikation 
herausgegeben. Ein Verzeichnis aller Hefte einschlielich der 
Druckausgaben (Heft 377-568) sowie der frheren "Berichte zur 
Polarforschung" (Heft 1-376, von 1981 bis 2000) befindet sich im open 
access institutional repository for publications and presentations (ePIC) 
des AWI unter der URL http://epic.awi.de. Durch Auswahl "Reports on 
Polar- and Marine Research" (via "browse"/"type") wird eine Liste der 
Publikationen sortiert nach Heftnummer innerhalb der absteigenden 
chronologischen Reihenfolge der Jahrgnge erzeugt. 

To generate a list of all Reports past issues, use the following URL: 
http://epic.awi.de and select "browse"/"type" to browse "Reports on Polar 
and Marine Research". A chronological list in declining order, issues 
chronological, will be produced, and pdf-icons shown for open access 
download. 


Verzeichnis der zuletzt erschienenen Hefte: 

Heft-Nr. 638/2011 – "Long-term evolution of (millennial-scale) climate 
variability in the North Atlantic over the last four million years - 
Results from Integrated Ocean Drilling Project Site U1313", by Bernhard 
David Adriaan Naafs 

Heft-Nr. 639/2011 – "The Expedition of the Research Vessel 'Polarstern' 
to the Antarctic in 2011 (ANT-XXVII/4)", edited by Saad El Nagger 

Heft-Nr. 640/2012 – "ARCTIC MARINE BIOLOGY -A workshop celebrating two 
decades of cooperation between Murmansk Marine Biological Institute and 
Alfred Wegener Institute for Polar and Marine Research", edited by 
Gotthilf Hempel, Karin Lochte, Gennady Matishov 

Heft-Nr. 641/2012 – "The Expedition of the Research Vessel 'Maria S. 
Merian' to the South Atlantic in 2011 (MSM 19/2)", edited by Gabriele 
Uenzelmann-Neben 

Heft-Nr. 642/2012 – "Russian-German Cooperation SYSTEM LAPTEV SEA: The 
Expedition LENA 2008", edited by Dirk Wagner, Paul Overduin, Mikhail N. 
Grigoriev, Christian Knoblauch, and Dimitry Yu. Bolshiyanov 

Heft-Nr. 643/2012 – "The Expedition of the Research Vessel 'Sonne' to the 
subpolar North Pacific and the Bering Sea in 2009 (SO202-INOPEX)", edited 
by Rainer Gersonde 

Heft-Nr. 644/2012 – "The Expedition of the Research Vessel 'Polarstern' 
to the Antarctic in 2011 (ANT-XXVII/3)", edited by Rainer Knust, Dieter 
Gerdes and Katja Mintenbeck 

Heft-Nr. 645/2012 – "The Expedition of the Research Vessel 'Polarstern' 
to the Arctic in 2011 (ARK-XXVI/2)", edited by Michael Klages 

Heft-Nr. 646/2012 – "The Expedition of the Research Vessel 'Polarstern' 
to the Antarctic in 2011/12 (ANT-XXVIII/2)", edited by Gerhard Kattner 

Heft-Nr. 647/2012 – "The Expedition of the Research Vessel 'Polarstern' 
to the Arctic in 2011 (ARK-XXVI/1)", edited by Agnieszka Beszczynska-Mler 

Heft-Nr. 648/2012 – "Interannual and decadal variability of sea ice 
drift, concentration and thickness in the Weddell Sea", by Sandra 
Schwegmann 

Heft-Nr. 649/2012 – "The Expedition of the Research Vessel 'Polarstern' 
to the Arctic in 2011 (ARK-XXVI/3 - TransArc)", edited by Ursula Schauer 
 


CCHDO Data Processing Notes 

• File Online Carolina Berys 
06AQ20110805.exc.csv (download) #15b52 Date: 2018-10-09 Current Status: 
unprocessed 

• File Online Carolina Berys 
PS78-2011-CO2-System-Meta-Data.pdf (download) #ef25e Date: 2018-10-09 
Current Status: unprocessed 

• File Online Carolina Berys 
ARK-XXVI_3_phys_oce.tab.tsv.zip (download) #081f1 Date: 2018-10-09 
Current Status: unprocessed 

• File Submission RobertKey 
ARK-XXVI_3_phys_oce.tab.tsv.zip (download) #081f1 Date: 2018-09-12 
Current Status: unprocessedNotes 
Data originated in several files on PANGAEA. References given in bottle 
data headerNo work done on CTD data No cruise report included here, but 
may exist 

• File Submission RobertKey 
PS78-2011-CO2-System-Meta-Data.pdf (download) #ef25e Date: 2018-09-12 
Current Status: unprocessed Notes 
Data originated in several files on PANGAEA. References given in bottle 
data headerNo work done on CTD data No cruise report included here, but 
may exist 

• File Submission RobertKey 
06AQ20110805.exc.csv (download) #15b52 Date: 2018-09-12 Current Status: 
unprocessed Notes 
Data originated in several files on PANGAEA. References given in bottle 
data header
No work done on CTD data No cruise report included here, but may exist 





Principal Investigators /Measurements 

Institute  Principal         Type of                   Comments 
           Investigator      measurements
—————————  ————————————————  ————————————————————————  ———————————————————
   AWI     Hirche, H.J.      B09                       Sea ice 
                             Zooplankton               ecosystem

   AWI     Hirche, H.J.      B09                       -
                             Zooplankton

   AWI     Matthissen, Jens  G90                       Sea ice
                             Other geological or       thickness and
                             geophysical measurements  physical properties

   AWI     Nicolaus, Marcel  G90                       Paleontology 
                             Other geological or         
                             geophysical measurements

   AWI     Rutgers van der   G90                       Sea ice
           Loef, Michiel     Other geological or       surface properties
                             geophysical measurements

   AWI     Rutgers van der   H09                       Nutrients,
           Loef, Michiel     Water bottle stations     radionuclides,
                                                       trace metals,
                                                       biogeochemical 
                                                       parameters 

   AWI     Schauer, Ursula   H10                       -
                             CTD-Stations

   AWI     Damm, Ellen       H73                       Methan content
                             Geochemical tracers       and isotopes
                             (e.g. freons)      
