CRUISE NARRATIVE (S04A, SR04) Highlights WHP Cruise Summary Information WOCE section designation S04A, SR04 Expedition designation (ExpoCode) 06AQANTXIII_4 Chief Scientist and affiliation Eberhard Fahrbach/AWI Stiftung Alfred-Wegener-Institut für Polar und Meeresforschung Fachbereich Klimasystem Postfach 120161, D-27515 Bremerhaven Phone (+49) (0)471 4831-1820 FAX (+49) (0)471 4831-1797 Office: Bussestr. 24 http://www.awi-bremerhaven.de email:efahrbach@awi-bremerhaven.de Dates 1996.MAR.17 - 1996.MAY.20 Ship RV Polarstern Ports of call Cape Town, S Africa to Punta Arenas, Chile to Bremerhaven, Germany Number of stations 104 44° 0.35' S Stations' Geographic boundaries 53° 37.44' W 38° 59.81' E 71° 1.30' S Floats and drifters deployed 0 Moorings deployed or recovered 3 recovered; 14 deployed Contributing Authors: Matthias Alpers/IAPR Andreas Hansjosten/AWI Erika Mutschke/UMAG MarcoAntonio/UACH Josef Hbffner/IAPR Jochen Nowaczyk/AWI Wolf Arntz/AWI Elisabeth Helmke/AWI Martin Rauschert/AWIP Karl Bakker/NIOZ Miriam de las Heras/AWI Carlos Rios/UMAG Anke Bittkau/AWI Josepf Höffner/IAPR Gerd Rohardt/AWI Harald Bohlmann/AWI Mario Hoppema/AWI Harald Rohr/AWI Klaus Bulsiewicz/IUPB Mario Hopperna/AWI Malte Runge/IUPB Alexander Buschmann/AWI Uta Horstmann/AWI Björn Schlenker/IUPB Lardies Carrasco/UACH Markus Jochum/AWI Michael Schröder/AWI Nicola Jane Debenham/NHM Ulla Klauke/AWI Hiltrud Sieverding/IUPB Corinna Dubischar/AWI Edmund Knuth/DWD Vassili Spiridonov/ZMMU Erich Dunker/AWI Herbert KöhIer/DWD Michel Stoll/NIOZ Joachim England/DWD Leif Kolb/AWI Birgit Strohscher/AWI Veit Eska/IAPR Peter Albert Lamont/SAMS Giok Nio Tan/AWI Eberhard Fahrbach/AWI Katrin Linse/IPO Tanja Winterrath/AWI Timothy John Ferrero/NHM Pedro Martinez-Arbizu/FBZO Andreas Wisotzki/AWI Gerhard Fraas/IUPB Ralf Meyer/AWI Hannelore Witte/AWI Kai Horst George/FBZO Anneke MOhlebach/AWI Rebecca Woodgate/AWI Dieter Gerdes/AWI Hans-Joachim Möller/DWD Ulf von Zahn/IAPR Janja Gorny/AWI Americo Montiel/UMAG Andreas Zimmermann/AWI Matthias Gorny/AWI Gisela Silveira Moura/FBZO 1.1 Summary and Itinerary The Polarstern-cruise ANT XIII/4 started on March 17th, 1996 in Cape Town. The first part of the cruise consisted of multidisciplinary work with a focus on physical oceanography in the Weddell Sea, during the second part logistic tasks were carried out at King George Island and a benthological programme was performed in the Drake Passage. During the whole cruise, temperature measurements were made with a newly developed potassium temperature lidar, which was designed to measure the natural variations in temperature of the mesopause at different geographical locations and in different seasons. The high temporal and vertical resolution of the lidar together with the simultaneous observations of the potassium layer allowed better insight into dynamic processes in the upper atmosphere. A major part of the deep and bottom waters of the global ocean are ventilated by the injection of waters from the Weddell Sea. Cooling in winter and sea ice formation, as well as the interaction between the ocean and the ice shelves, induce water mass modifications which generate water masses on the shelf which are dense enough to sink to the bottom of the Weddell basin. During their descent, they mix with ambient water masses and are carried with the cyclonic Weddell gyre circulation to the north. The formation of bottom and deep water determines the exchange of atmospheric carbon dioxide (C02) between the ocean and the atmosphere. Through the upwelling of C02-rich deep-water, C02 can be given up to the atmosphere, a process which counteracts the C02 flux due to cooling and biological processes at the surface. Thus the components of the C02 system were measured to determine whether the Weddell Sea is a source or a sink for atmospheric C02. The physical oceanography measurements of the cruise contribute to the World Ocean Circulation Experiment, (WOCE). The hydrographical sections are referred in the WOCE code as the repeat sections SR2 and SR4 and the Atlantic part of the S4-section. In order to better understand the processes and effects which are important in this area, the programme consisted of four components. 1. To determine the inflow from the Antarctic Circumpolar Current into the eastern Weddell Sea, a hydrographical section was worked from 24°41'E to 39°E, using a CTD-probe (Conductivity-Temperature with Depth) in connection with water samplers and an ADCP (Acoustic Doppler Current Profiler). 2. The outflow of the bottom water from the east into the western Weddell Sea was measured by a zonal hydrographical section along the eastward current in the north of the Weddell gyre from 0' to 24°41 E. 3. The exchange between the eastern and western Weddell Sea was measured on a meridional hydrographical section through the Weddell gyre along the Greenwich Meridian. Here, in addition to the use of the CTD-sensor, water samplers and ADCP, moorings were also recovered and deployed. 4. To determine the inflow into the southern Weddell Sea from the east and the outflow in the north-west, a hydrographical section was performed through the southern Weddell Sea and moorings were deployed near Joinville Island. Among other uses, these measurements will be used to validate models which simulate the circulation and water mass formation in the Weddell Sea. The isotopes of oxygen, including 180, nutrients and the tracers Freon-11, Freon-12, Freon-113 and CCl4, as well as Tritium, 3He, He and Ne give information about the water mass formation and spreading. Samples of the stable carbon isotope 613C were taken for paleo-oceanographic studies. The marine organic chemistry group concentrated on the autumn distribution of dissolved and particulate phytosterols in the Weddell Sea to understand the fate of phytosterols and other trace organic compounds in the ocean starting with biosynthesis and input into the euphotic zone and ending with the possible final deposition into the bottom sediments of the deep sea. Planktological studies focused on the distribution of some dominant zooplankton and micronekton species such as Calanoides acutus and Rhincalanus gigas (the two dominant Copepodes of the Antarctic), which show a clear dependence on the oceanographic structure of the Weddell gyre. These species very probably do not reproduce in the western Weddell Sea. Thus the population is maintained by the advection of individuals who have over-wintered in the Warm Deep Water and by local recruitment in the eastern Weddell gyre. The presence of Antarctic krill, Euphausia superba, in the eastern Weddell gyre seems to play a important role in the maintaining of the krill population in the Atlantic sector of the southern polar seas. Krill can be brought into the Weddell Sea by the advection of krill- larvae with the inflow of Warm Deep Water, although adult krill are usually found at shallower depths. On this cruise, the formation of the over-wintering population of the larger calanoid Copepods and the abundance of the krill-larvae in the Warm Deep Water was measured using the Acoustic Doppler Current Profiler (ADCP) and an Optical Plankton Counter (OPC) in combination with conventional net sampling. The Chlorophyll-concentration at different depths along all the sections was measured and combined qualitatively with the phytoplankton determined from the water samples. Investigations of the Antarctic zooplankton ecology focused on the completion of the reproductive periods of various species which shows a strong geographical variation. The transition of several dominant zooplankton species to over-wintering was studied in different areas of the Weddell Sea. Using the Multinet catches, the vertical distribution of the different stages of development of the Copepodes was determined. The second part of the cruise concentrated on the investigation of the ecological relationship between the marine fauna of the Antarctic Peninsular and the southern-most part of South America. South America is the closest present- day land mass to Antarctica. Thus it is assumed that the exchange between South America and Antarctica has been longer and more intense than with the other continents. Due to bad weather, the benthological group were unable to fly to King George Island. Also the collection of material from the Dallmann laboratory, which is connected to the Argentinean Jubany-Station, could only be completed to a limited extent. The unfavourable weather conditions meant the activities planned for King George Island were cancelled and the work concentrated instead on the continental slope south of Terra del Fuego. During the "Joint Magellan VICTOR HENSEN Campaign 1994", a large number of samples were collected in shallow and deep water in the Magellan Straits (to a depth of 650 m), in the northwestern part of the Beagle Canal and from the eastern exit of the Beagle Canal to Cape Horn. On this cruise, along a section on the northern continental slope of Drake Passage, at different depths samples were taken with the Multicorer, the Multibox Corer, the Dredge and the underwater-camera to study the macro and meiozoobenthic structure, and to complete the available benthic samples with material obtained from greater depths. In addition, samples were taken for physiological, biological reproduction and population dynamic experiments. Finally, observations were made of behaviour patterns and material was gathered for genetic work. It appeared that the transition to the Antarctic is rather of a gradual nature than abrupt. Despite this fact, considerable differences remain between the Antarctic and this southernmost part of the Magellan region. This indicates that 20 million years of separation and isolation, despite some glacial periods of 'Increased interchange, have led to rather distinct separation of two neighbouring marine ecosystems which originally had an identical fauna. Supporting hydrographic data was acquired with the CTD. The cruise ended in Punta Arenas on May 20th, 1996. The cruise track is displayed in Fig. 1. 2. Scientific programmes 2.1 Investigations of the atmosphere 2.1.1 Weather Conditions (Hans-Joachim Möller, Herbert KöhIer/DWD) The passage from Cape Town to 54°S 39°E was dominated by a subtropical high with moderate winds but many clouds. South of 50°S, the first frontal troughs were crossed. The following westward passage was characterized by the alternation of deep lows and small wedges of high pressure. Westerly winds between 25 and 35 knots were most frequent. While passing through gale centres and frontal troughs the wind increased up to Force 9 for a short time, but also decreased to Force 4 when passing through the wedges. The passage to the northeast to the mooring position in the oceanic Polar Front was favoured by a meridional trough, followed by a strong wedge of high pressure. On the way to the meridional hydrographic section on the Greenwich Meridian the strong westerly wind regime prevailed. The following passage south was dominated by a large polar low, filled with cold air. For many days, showers with snow and soft hail occured. At the beginning of the second part of April, a cold air flow in the middle troposphere formed a meridional trough, which reached far north to the coast of Uruguay. This trough moved south-eastward, carrying cold antarctic air in its back, The corresponding surface low deepened rapidly to a gale with its centre between Bouvet Island and the Antarctic coast. The minimum pressure at the centre was less than 950 hPa, with RV "Polarstern" situated south of the it. For 36 hours, northeasterly to easterly winds of about 35 knots were observed with a heavy swell. The first pancake ice was encountered at 69°09'S on April 21th about 30 nm north of the ice shelf edge. Before this time, only isolated icebergs had been passed, but now many bergs and growlers, frosted in the pack ice were observed. The wedge of a high pressure system, situated at the western Weddell Sea, extended more and more to the east. On April 24th, when we reached the Atka Bight, the finest calmy and sunny weather was experienced. For the next days, this high pressure zone influenced the Weddell Sea. At the end of April, a gale centre was formed in the Scotia Sea and consequently the southeasterly winds increased to gale force for a short time. The rising pressure, resulting from the following wedge, calmed the weather down rapidly. Further lows were encountered during the passage through the ice of the southern Weddell Sea. A southeasterly to southwesterly airflow was at their back, whilst northeasterly to northwesterly winds dominated at their front. The situation during May 4th/5th can serve as an example: Over the western Weddell Sea, a trough was generated. Warm air was advected southward at its front with northwesterly winds Force 6. The air temperature rose continuously, from -170 C in the morning until it reached its maximum of +1°C at 23.00 UTC. The warm air flow brought a high humidity, low stratus clouds and poor visibility. The passage of the trough at 00.00 UTC was accompanied by a decreasing westerly wind, but not by a change in temperature. The strongly backing, southwest wind caused a powerful cold air advection. The temperature dropped to -7°C in one hour, and after 12.00 UTC of May 5th to below -21°C, in spite of continual sunshine. In the northern part of the Weddell Sea, mostly young ice up to 30 cm thick was observed. West of 50OW however, large first-year or multiyear ice floes with thickness between 3 and 5 m reduced the ship's speed considerably. The ice edge had been shifted far west-northwest by continuous southeasterly winds with a speed up to Force 8. Wind and tides exerted a strong pressure on the ice, restricting seriously the progress of the cruise. The ice edge was reached on May 11th at 18 UTC near 62.2° S 57°W. At this position in Bransfield Strait a chain of icebergs lined up the ice edge like a barrier. The crossing of the Drake Passage was favoured by a zone of high pressure, which extended from Argentina via the Magellan region and the Drake Passage to the southern part of the Antarctic Peninsula. The high pressure system moved east only very slowly and dominated by weak winds until the middle of May. Then, a more cyclonic westerly situation developed, but strong westerly winds were not encountered until the very end of the cruise, because the pressure difference between the subtropical high and the polar trough was rather weak. Westerly to northwesterly winds accounted for more than 40% of the hourly observations of ANT XIII/4. Wind forces 5, 6 and 7 were each recorded 20% of the time. Gales occured only 7% of the time, although the climatological value is nearly 20%. The frequency distributions of wind speed and direction is displayed in Fig. 2. 2.1.2 Temperature observations in the mesopause (Josepf Höffner, Veit Eska/IAPR) Objectives The major task of the IAPR-group was to test the new potassium temperature lidar of the Institute of Atmospheric Research at the Rostock university and to the make first measurements. Routine observations were planned to take place on ANT XIII/5 when better weather conditions were expected. Therefore we planned to build up a stable configuration for our untested lidar system. The main part of our temperature lidar is a new high energy, narrow band, tuneable and pulsed alexandrite laser. The laser pulses are used for resonance scattering from free potassium atoms in the mesopause region. The backscattered photons are collected by a telescope and recorded by a photomultiplier. The scattering altitude is calculated from the time-of-flight of the light. It is possible to measure the Doppler broadening of the K(D1) fine structure by continuous spectral tuning of the alexandrite laser. This method allows an absolute air temperature determination 'in the scattering volume. Vertical wind velocities within the potassium layer are measured by Doppler shifted frequencies of the fine structure. A combination of Rayleigh backscattering and resonance scattering allows temperature measurements in the mesosphere and stratosphere down to 30 km. Potassium acts as a tracer for our temperature measurements. Up till now, potassium measurements have been made with only three lidar systems. All took place in the northern hemisphere. Our measurements of the potassium layer are the first with a potassium temperature lidar in the southern hemisphere. The southernmost other temperature measurements in the mesopause at an altitude of 80 to 110 km, we are aware of, occured at 31°S in Australia. Our first measurements indicated, that enough potassium is present in the southern atmosphere for temperature measurements from somewhat less than 80 km up to 110 km height. This altitude range is the coldest in the whole atmosphere and thus very interesting. With our lidar system, we are able to continuously measure these temperatures. This is only possible with a ground/ship based lidar system. Preliminary results Observations of the potassium layer have been performed for 16 nights during the entire cruise. Eleven nights were suitable for temperature measurements in the mesopause. Temperature measurements require nearly 30 minuntes, whereas the potassium density can be determined in a few minutes. Several nights allowed us measurements of up to 12 hours and it was possible to observe changes in the temperatures on one night. These observations are the longest made with this lidar system. The measured structure of the potassium layer is very similar to the that observed on the Isle Ruegen in spring 1995. It is a broad layer and extends from 78 km up to 120 km height. The density maximum is nearly 20 atoms/CM3. At a height of 120 km the potassium density is only 0.01 atoms/cm3. The column density is nearly 20 Mio. atoms/cm2. We have not observed significant monthly differences in column density of potassium in April and May. On one of the first measured nights, we observed a peak in the potassium layer density. This could be a sporadic potassium layer, seen as a sudden rise in density. The extent of this layer is very small. The measurements were too short to observe this previously unknown phenomenon because of cloudy weather this night. A measured backscattered profile collected during the night from May 2th to 3th is shown in Fig. 3 (left) and a temperature profile up to 106 km height in the same night in Fig. 3 (right). The mesopause temperature was distinctly higher than that of the reference atmosphere CIRA '89. Measurements on the other nights showed similar results. A second local minimum lies in 83 km height. The backscattered signal (Fig. 3, right) shows a Rayleigh backscattering within the potassium layer, which helps to determine temperatures down to 35 km in the stratosphere. The dynamic variability of the potassium layer during one night is displayed in Fig. 4. The lower boundary of the layer moves up and down more than once during the night. The reason is probably wave activity. The shape and location of the layer change continously. The density maximum of the layer is higher at the end of the night than at the beginning. Similar tendencies also exist on the other measured nights. For more detailed analysis, we must improve and expand our software. 2.2 Physical Oceanography 2.2.1 Deep and Bottom Water Formation in the Weddell Sea (Eberhard Fahrbach, Janja Gorny, Andreas Hansjosten, Miriam de las Heras, Uta Horstmann, Markus Jochum, Leif Kolb, Ralf Meyer, Gerd Rohardt, Harald Rohr, Michael Schröder, Giok Nio Tan, Tanja Winterrath, Andreas Wisotzki, Hannelore Witte, Rebecca Woodgate/AWI). Objectives A major part of the deep and bottom waters of the global ocean are ventilated by an injection of waters from the Weddell Sea. Cooling in winter and sea ice formation, as well as the interaction between the ocean and the ice shelves, 'Induce water mass modifications which form water masses on the shelf which are dense enough to sink to the bottom of the Weddell basin. During their descent, they mix with ambient water masses and are carried with the cyclonic Weddell gyre circulation to the north where they partly leave the Weddell Sea towards the Antarctic Circumpolar Current and partly recirculate, steered by topographic features. The increase in density due to cooling in the Weddell Sea counteracts the decrease in salinity due to precipitation and melting of ice shelf or icebergs. This increase in freshwater can similarly be compensated by the inflow of salty, deep water from the Antarctic Circumpolar Current, a process which takes place predominantly in the eastern Weddell gyre. This water mass is observed as Warm Deep Water. During its path through the cyclonic gyre, it constantly loses heat and salt. The warm regime is typified by the relatively warm conditions in the southeast of the gyre, which are determined by the close proximity of the inflow in the eastern Weddell Sea. The cold regime in the northeast is created by the cooling of the Warm Deep Water in the course of its circulation through the gyre. The inflow 'is subject to intense fluctuations which are partly generated by the interaction of the flow with the bottom topography. The kinematics and dynamics of the fluctuations will be investigated to understand the variations of the inflow. In the Weddell Sea, these fluctuations are of importance because of their effect on the vertical stability and consequently vertical mixing in the open ocean. This can affect the sea ice cover to the extent of the generation of open ocean polynyas and the possibility of the formation of deep water. To quantify these processes, measurements were carried out of the water mass characteristics and transport of the inflow in the eastern Weddell Sea, the exchanges between the eastern and the western Weddell gyre and the outflow into the Weddell-Scotia Confluence. The geostrophic transport determination will be optimized by quasi-synoptic measurements at various locations. The ageostrophic parts of the current field will be assessed by direct current measurements. To estimate the relevance of the results obtained, long-term measurements of the inflow, the mixing depth and the characteristics of the deep water were initiated. Because of the impact of the sea ice formation on the water mass modification, it is planned to measure the variations of the meridional profile of the sea ice thickness and concentration with moored instruments to identify possible interactions between sea ice and mixing variability. The measurements on the section will be repeated in part several times, to ascertain the longer time scale variations in the properties and distribution of the water masses. The measurements will be used to validate models of the Weddell gyre circulation and the water mass formation. For this purpose, long time series of oceanic currents and water mass characteristics, as well as of the atmospheric forcing and the sea ice cover, are required to investigate the response of the system to variations of the forcing conditions. The measurements of the physical oceanography programme are a contribution the World Ocean Circulation Experiment (WOCE). The hydrographic sections represent a contribution to the WOCE-section S4 and the repeatsections SR4 and SR2. The moorings in the western Weddell Sea are part of the international DOVETAIL (Deep Ocean VEntilation Through Antarctic Intermediate Layers) Project, which is part of the iAnzone Programme. Through these international projects, instruments are also provided from the Universitat Politecnica de Catalunya in Barcelona, Spain. Work at sea The programme consists of measurements from ship, using the CTD-probe (Conductivity and Temperature with Depth) connected to a water sampler, XBTs (eXpendable Bathythermographs) and both ship-borne and lowered ADCP (Acoustic Doppler Current Profiler). In addition, 3 moorings were recovered and 14 moorings deployed. The investigation is split into four geographical regions. 1. To determine the inflow from the Antarctic Circumpolar Current into the eastern Weddell Sea, a hydrographical section, consisting of 14 CTD and water sample casts, was performed from 39°E to 24°41'E (Figs. 5 and 6). 2. To determine the intensity of eddy activity in the transition region between the Antarctic Cirumpolar Current and the Weddell gyre, time series are collected over many years. To this aim, moorings were recovered and re- deployed (see Fig. 5, Tab. 1 and 2) and XBTs were used to measure between the CTD stations (Figs. 10 -12). 3. The exchange between the eastern and western Weddell Sea will be derived from a zonal hydrographical section along the eastward current in the north of the Weddell gyre from 00 to 24041E consisting of 15 stations and a perpendicular merldional hydrographical section of 32 stations through the Weddell gyre along the Greenwich Meridian from 55°S to the ice-shelf edge at 69°38.5'S (Figs. 5, 7 and 8). The Greenwich Meridian section was already sampled once in 1992. In addition, 8 moorings were deployed (Figs. 5 and 13, Tab. 1). 4. To determine the inflow into the southern Weddell Sea from the east and the outflow in the north-west, a hydrographical section of 36 stations was performed through the southern Weddell Sea (Figs. 5 and 9). This was the fourth repeat of this section since 1989. Six moorings were deployed near Joinville Island (Figs. 5 and 13, Tab. 3). Table 1: Moorings deployed on the Greenwich Meridian. Mooring Latitude Date Water Type SN Depth Longitude Time(UTC) Depth(m) (m) --------- ---------- --------- -------- ------- ------- ----- B06 54° 20.6'S 07.04.96 2677 AVTP 9763 250 03° 17.0'W 12:09 AVTPC 9193 399 ACM-CTD 1391 400 AVTP 9182 1493 ST 890109 2280 AVT 9186 2685 AW1228-1 57° 00.0'S 13.04.96 3857 AVTP 11887 434 00° 00.2'W 15:30 ACM-CTD 1389 795 AVT 9768 2090 ACM-CTD 1387 3812 AW1227-3 59° 01.8'S 04.04.96 4605 ULS 10 156 00° 00.0'W 19:00 AVTP 9201 262 AVTP 9211 698 SC 1978 699 ACM-CTD 1392 700 AVT 9190 2006 ST 860016 3373 AVT 9391 4554 SC 318 4553 ACM-CTD 1388 4552 AW1229-1 63° 59.6'S 14.04.96 5180 ULS 07 159 00° 00.3'W 11:05 AVTP 11888 209 SIC 1973 210 TC250 1570 240 TC250 1572 515 AVTPC 9786 778 SC 319 779 AVT 9770 2005 ACM-CTD 1400 5136 AW1230-1 66° 00.2'S 19.04.96 3449 ULS 25 51 00° 09.5'W 16:00 AVTPC 9765 91 SC 1166 92 TC250 1426 123 TC250 1427 399 AVTPC 9215 664 SC 1167 665 AVT 10498 1671 ACM-CTD 1411 3406 AW1231 -1 66° 30.O'S 20.04.96 4513 ULS 26 160 00° 00.4'W 11:15 AVTPC 9213 209 SC 1976 210 TC250 1453 236 TC250 1569 512 AVTP 9212 778 SC 630 779 AVT 9561 1805 ACM-CTD 1390 4466 AW1232-1 69° 00.0'S 22.04.96 3361 ULS 24 147 00° 00.0'W 09:50 AVTP 11889 248 AVTPC 10491 754 AVT 10496 1960 ACM-CTD 1404 3317 AW1233-1 69° 24.2'S 22.04.96 2001 ULS 6 149 00° OO.7'E 15:40 AVTP 10492 255 AVTPC 9214 751 AVT 10499 1956 Table 2: Moorings recovered during ANT X111/4. Mooring Latitude Date Water Type SN Depth Record Longitude Time(UTC) Depth (m) length (1. Record) (m) (days) -------- ---------- ----------- ----- ----- ----- ----- ------ AW1227-2 59° 27.5'S 26-12.94 5096 AVTP 10002 250 424 03° 11.2'W 16:00 AVTP 9998 514 424 AVT 9179 1604 424 AVT 10531 3650 424 AVT 10532 5058 424 B05 54° 20.6'S 28.12.94 2674 AVTP 9766 215 425 03° 17.6'W 01:00 AVTPC 8037 425 425 AVT 9188 1520 425 AVT 9184 2627 425 PF8 50° 11.1'S 30.12.94 3868 AVTP 10541 301 426 05° 53.7'E 00:00 AVTPC 7727 799 426 AVT 10534 1594 426 AVT 10495 3100 426 AVT 10497 3815 426 Table 3: Moorings deployed in the western Weddell Sea. Mooring Latitude Date Water Type SN Depth Longitude Time(UTC) Depth (m) (m) -------- ---------- --------- ----- ------- ----- ----- AW1216-2 63° 57.6'S 06.05.96 3520 AVTIP 11926 262 49° 08.8'W 16:54 ACM-CT 1403 573 AVT 11885 2549 AVT 11886 3474 SC 631 3475 AW1207-4 63° 43.3'S 07.05.96 2510 ULS 08 174 50° 49.2'W 20:45 AVTPC 9207 270 TC250 2299 506 ACM-CT 1402 762 AVT 9767 2187 TC250 2371 2199 AVT 9206 2454 SC 1979 2455 AW1236-1 63° 34.3'S 08.05.96 1803 ACM-CT 1401 1648 51° 37.0'W 10:49 ACM-CT 1410 1759 AW1206-4 63° 29.6'S 08.05.96 960 ULS 09 157 52° 06.1'W 15:23 AVTIP 11890 254 ACM-CT 1409 499 AVT 9401 914 SC 1977 915 AW1215-3 63° 19.6'S 08.09.96 450 AVTIP 11892 244 52° 46.9'W 22:58 AVT 9402 444 WLR 1154 450 AW1234-1 62° 51.4'S 09.05.96 287 ADCP 378 278 53° 40.3'W 16:52 SC 1975 283 Abbreviations: --------------------------------------------------------------------------- ACM-CT Falmouth Scientific 3-dimension acoustic current meter with CTD sensor head (CTD=Conductivity, Temperature, Depth) ADCP RDI Inc. acoustic doppler current profiler AVTPC Aanderaa current meter with temperature, pressure, and conductivity sensor AVTP Aanderaa current meter with temperature and pressure sensor AVT Aanderaa current meter with temperature sensor SC SeaBird Inc. self contained CTD, type: SeaCat ST Sediment trap TC250 Aanderaa thermistor cable, 250 m length, 11 sensors 25 m spacing ULS Upward looking sonar Christian Michelsen Research Inc. The hydrographical work was carried out using CTD-probes and water bottle release mechanism built by Falmouth Scientific Insturments (FSI). Two instruments of the type Triton ICTD, SN 1347 and SN 1360 were used. The water bottle rosettes used were a 24-(12-l)-bottle rosette from General Oceanics Inc. and a 36-bottle rosette from FSI. It turned out however that to obtain a steady sink rate for the 36-bottle sampler, such a high extra weighting was required that safe handling of the rosette was no longer possible and there was the fear of breaking the winch cable. Thus only the 24-bottle sampler could be used. However, due to the intense swell 120 kg of extra weight were needed as well to avoid wire problems. The additional weights were removed once the instrument was on deck to facilitate moving the rosette to the sampling room. CTD MEASUREMENTS during 06AQANTXIII/4 Instruments: Falmouth Scientific ICTD, Sn: 3060 and Sn: 1347 Fallmouth Scientific Reference Grade Platinum Resistance Thermometer range : -2 - 32 deg C accuracy : +/- 0.003 deg C stability : +/- 0.0005 deg C/month resolution : 0.0001 deg C Falmouth Scientific Thermistor Sensor range : -2 - 32 deg C accuracy : +/- 0.010 deg C stability : +/- 0.001 deg C / month resolution : 0.0001 deg C Falmouth Scientific Titanium Pressure Sensor range : 0 - 7000 dbar accuracy : +/- 2.1 dbar stability : +/- 0.7 dbar/month resolution : 0.08 dbar Falmouth Scientific Inductive Conductivity Sensor range : 0 - 65 mmho/cm accuracy : +/- 0.003 mmho/cm stability : +/- 0.0005 mmho/cm/month resolution : 0.0002 mmho/cm Each CTD has two Platinum Resistance Thermometer Software : FSI Software for data aquisition CTD postprocessing in analogy to Version 1.12 Time lag : 0.10 s Despite these precautions, the CTD wire was damaged several times. During the comparatively long time taken to repair the wire, the CTD was deployed with the Aframe aft of the ship. The extreme pitching of the ship however put such strain on the rosette, that the water bottles were broken loose. This led to the loss of 23 water bottles, 9 electronic pressure sensors and 7 electronic thermometers. In addition, the conductivity cell on the CTD was damaged. This was repaired by converting a sensor from a mooring instrument. Until this repair was fully functioning, some profiles were either unusable or in need of serious correction. The high loading had affected the electric quality of the wire also and lead to errors in the data transmission, which was noticeable in readings from depths of 2000 m to 3000 m. In addition, electronic adjustment problems of the new CTDs lead to some profiles being noisy. These issues have resulted in a unexpected noisy data set which has to be cleaned with care. The noise affects all parameters. The removal is thus done for each profile separately, using an interactive graphic programme, which analyses the properties of the noise. Particular priority is given to obtaining reliable CTD values at the points where bottles were closed, so that a quality calibration correction can be made. The accuracy of the dataset is determined from laboratory calibrations both before and after the cruise. Since each CTD is equipped with two temperature sensors, the stability of the sensors can be controlled from a comparison of these readings. For instrument no. 1347, the calibrations before and after the cruise were performed by the Scripps Institution of Oceanography and FSI. For both sensors, the temperature drift in the relevant temperature range was less than 1 mK. Thus the pre-cruise calibration coefficients were used. For instrument no. 1360, where the conductivity sensor was repaired, only a post- cruise calibration at Scripps was possible. One of the sensors shows a jump in calibration values. Thus the post-cruise calibration was used. In addition, calibration on-board ship was performed using 13 electronic thermometers until they were lost and subsequently mercury reversing thermometers, calibrated by the Institut für Ostseeforschung in WarnemOnde were used. Deviations from the sensor readings occurred due to the scatter in the thermometer readings, so the accuracy of the laboratory calibration can be assumed to be the relevant error. When noise is also taken into account, this gives a final accuracy of 2 to 3 mK. ICTD-SN 1347; Cal_date: DEZ.95 Calibration: pre-cruise no post calibration used #PT1 a1 = -0.000699749 a2 = 0.000354949 a3 =-9.7419E-06 a4 =-8.44638E-07 a5 = 2.71068E-08 #PT2 a1 = 0.000359662 a2 = 0.000225676 a3 =-5.66405E-06 a4 =-4.91609E-07 a5 = 1.53814E-08 temperature pre-cruise calibration the temperature data are used only from PT1 T(corrected) = T(reading) + dT with dT = a1 +a2*T +a3*T**2 +a4*T**3 +a5*T**4 ai : T(calibrated)-T(reading) #PRES a1 = 1.02684 a2 = 0.000760568 a3 =-1.69817E-07 a4 =-6.67453E-11 a5 = 1.02023E-14 #UNLOAD PRES 0.0 pressure pre-cruise calibration p(corrected) = p(reading) + dp with dp = a1 +a2*p +a3*p**2 +a4*p**3 +a5*p**4 ai : p(calibrated)-p(reading) ICTD-SN 1360; Cal_date: JUN.96 Calibration: post-cruise no pre-calibration used #PT1 a1 = 9.40529E-05 a2 = 0.000256106 a3 =-7.04533E-06 #PT2 a1 =-0.00549481 a2 =-2.76548E-05 a3 = 3.05434E-07 temperature post-cruise calibration the temperature data are used only from PT1 T(corrected) = T(reading) + dT with dT = a1 +a2*T +a3*T**2 ai : T(calibrated)-T(reading) #PRES a1 = 1.08715 a2 =-0.000460084 a3 = 1.32763E-07 a4 = 1.35645E-11 a5 =-1.05971E-14 a6 = 9.25015E-19 #UNLOAD PRES 0.0 Pressure post-cruise calibration p(corrected) = p(reading) + dp with dp = a1 +a2*p +a3*p**2 +a4*p**3 +a5*p**4 +a6*p**5 ai : p(calibrated)-p(reading) after calibration the platinum temperature is summed with the fast thermistor as follows: F(t) = F(t-dt)*W2+Fi(t)*(1-W2) filtered fast thermistor F'(t) = Fi(t)-F(t) high pass filtered fast temperature T(t) = Ti(t)+F'(t) summed platinum and fast thermistor with W2= exp(-dt/TtauF) dt is the CTD observations intervall in seconds dt = 48ms TtauF is the Platinum thermometer time constand in seconds relative to the fast thermistor TtauF = 100 ms Ti is the unfiltered platinum temperature = T(corrected) Fi is the unfiltered fast thermistor The CTD-temperature is IPTS-68 Correction of the CTD-conductivity data with the bottle-samples COND(corrected) = COND(CTD) - COND(delta) with COND(delta)= average(COND(CTD)-COND(WATERSAMPLE)) Station/Cast COND(delta) 00201 -0.0200 00202 -0.0107 00301 -0.0107 00401 -0.0200 00501 to 01303 -0.0107 01403 -0.0179 01502 to 01601 +0.0088 01701 +0.0080 01903 +0.0005 02201 to 02301 -0.0065 02401 to 02601 +0.0082 02701 to 03403 -0.0108 03404 +0.0020 03501 to 07201 -0.0108 07301 +0.0082 07402 to 08201 -0.0133 08302 -0.0026 08401 to 10301 -0.0133 The following 71 stations are filtered between around 2000 to 3000 dbar. In these stations was a noise in 2500 dbar which was estimated as an hardware error. 00201 to 00601 01201 01303 01403 01601 01701 01903 02203 to 02401 02503 02601 02901 03104 03201 03804 to 04401 05403 05501 05604 06004 to 06502 07001 07201 to 07801 07903 to 08901 09004 to 09301 09403 to 09801 10001 CTD station 01801 wrong conductivity data CTD station 01901 wrong conductivity data CTD station 02001 wrong conductivity data CTD station 02101 wrong conductivity data CTD station 07201 from 2604 dbar to bottom no conductivity data CTD Files column 5 : transmissiometer raw data range between 0 and 5 Volt these data are not controlled The *.SEA file is not ready. It will be send later. For CTD no. 1347, a pressure calibration was performed before and after the cruise at Scripps and at FSI. No change was recorded. For CTD no. 1360, a calibration at FSI was performed before and at Scripps after the cruise. The correction was of order 2db. The calibration of the pressure sensors is good to better than 2db. The conductivity was corrected using salinity measurements from water samples. IAPSO Standard Seawater from the P-series P127 was used. A total of 2477 water samples were measured using a Guildline Autosal 8400B. For stations 18, 19, 20, 21, the CTD conductivity profile was unusable, so a salinity profile was reconstructed from water sample values. On the basis of the water sample correction, salinity is measured to an accuracy of 0.003. In addition, the CTD also carried an altimeter from Benthos Undersea Systems Technology Inc. to determine distance above the sea floor and a transmissometer with a 25 cm light path from SeaTech Inc.. At all stations, oxygen samples were taken from the entire water column, (in total 2400 samples). The determination of oxygen was carried out in line with WOCEstandards for 02-measurement, as per Carpenter, 1965. Two radiation counters from SIS were used. For more than 10% of the samples, doubles, covering the entire range Of 02-values (180-350 µmol/l), were also measured. Using this data, a percentage error of 0.2% was obtained. This is below the WOCE-standard of reproducibility of 0.5%. Oxygen profiles were not measured as oxygen sensors fail under freezing conditions. To measure the stable isotope 180, 1713 samples were taken at 83 stations. For paleooceanographic investigations, 1350 samples for later analysis for 613C were taken at 67 stations. Preliminary Results The section from 390 to 4°41'E along 54°S reached from the foot of the Conrad Rise to the Southwest Indian Ridge (Fig. 5). In this area, the Antarctic Circumpolar Current has a strong southward component. This can be clearly seen in the distinct core layers of the Upper and Lower Circumpolar Deep Water (Fig. 6). The Southern Circumpolar Current Front is found at station 13 at 27°23'E. The near-bottom layer, which reaches from the western slope to the Southwest Indian Ridge, is relatively cold due to the influence of Bottom Water, which flows out of the western Weddell Sea along the mid-ocean ridge to the east. As this core is not to be found on the slope of the Conrad Rise, it must exit into the Indian Ocean. The structure of the surface layers is resolved at the mesoscale from the XBT-section (Fig. 11). The section from the Greenwich Meridian to the east (Fig. 7) follows the eastward current in the north of the Weddell gyre. At the depth of the Warm Deep Water, relatively cold temperatures, less than 0.3°C, show the cold regime. The boundary of the Weddell gyre, the Weddell Front, lies between stations 18 and 19. The temperature of the Weddell Sea Bottom Water of less than -0.7°C increases from west to east, reflecting the entrainment of surrounding water. The circulation perpendicular to the section is also evident from a doming of the isolines. This is caused by a northwards extension of the abyssal plain between 10 and 15°E (Fig. 5), and appears as a northwards current in the west of the section and a southward one in the east. The section along the Greenwich Meridian (Fig. 8) cuts the cyclonic Weddell gyre meridionally. In the south, a deepening of the surface layer towards the continent and the onset of winter temperatures is observed. This part of the section was already covered with sea-ice and can be counted as the Antarctic Coastal Current. The warm regime occurs to the north, with temperatures in the Warm Deep Water of more than 1°C, caused by the proximity of the inflow of the Antarctic Circumpolar Current. This warm regime is disturbed by Maud Rise, where noticeably colder temperatures are measured in the Warm Deep Water. The decrease in temperature further to the north signifies the cold regime, in which the eastward current 'is found. Near the bottom, cold temperatures show the flow of Bottom Water moving east out of the western Weddell Sea, leaning against the mid-ocean ridge. The Weddell Front lies at 55°30'S, between stations 36 and 37. The southern part of the Weddell gyre, in which the major water mass transformations occur, is separated from the inflow and outflow regimes by the section from Kapp Norvegia to Joinville Island (Fig. 9). The surface layer already shows winter conditions with temperatures around the freezing point. The deepening of the surface layer towards the coast, due to on-coastal Ekman transport and convection in the coastal polynya, is clearly visible on both sides of the section. The inflow of relatively warm Warm Deep Water can be seen in the east. The outflow in the west is noticeably colder. On the western slope, a layer of newly formed bottom water flows to the north. The sections form part of the WOCE "Repeat sections" Programme. Comparison with the data of 1992 on the Greenwich Meridian Section and the 1989/1990/1992 sections through the western Weddell Sea show a clear change in the deeper layers. In the bottom water of the western Weddell Basin, a continual warming over this 6 year period is observed. This trend is confirmed by results from moored instruments. The warming is of order 0.01 K per year. The investigation of the cause of this warming is still on-going. However, the increase in temperature in the Warm Deep Water regime suggests a change in the inflow of water from the circumpolar current. 2.2.2 Tracer measurements (Klaus Bulsiewicz, Gerhard Fraas, Malte Runge, Björn Schlenker, Hiltrud Sieverding/IUPB) Objectives and methods Along the sections, the CFCs Freon-11, Freon-12, Freon-113 and CCl4 were measured on board by ECD gas chromatography. This is the first time F113 and CCl4 have been measured in this region over a complete section. F113 has been released into the atmosphere at a known rate since the early sixties and has been taken up by the oceans by the surface transfers. Therefore it can be used to characterize the younger water. Similarily CCl4 has been released into the atmosphere since about 1920, so that it characterizes the older water. In addition to the analysis done on board, water samples for CFC measurements were stored 'in flame-sealed ampoules which will be analysed ashore and will provide reference measurements for the analysis carried out on board. Water samples for tritium and helium were taken also. They will be extracted after the cruise and analysed with a mass spectrometer. All gases will be extracted from the tritium samples which will then be stored for half a year. After this time, a sufficient amount of tritium will have decayed to 3He so that it can be measured by the mass spectrometer. The data sets provide important information about circulation and renewal pathways for all relevant subsurface water masses. Work at Sea The water samples were taken from the rosette water sampler using flow-through containers consisting of a glass ampoule (CFMs), copper tubes (helium) and glass bottles (tritium). In total, 104 stations were sampled and 2016 water samples for the CFMs were analyzed during this cruise. In addition, 785 standard gas and blank measurements were taken periodically. In total, 1418 water samples were collected for analyses ashore, including 200 water samples for CFC, 623 water samples for helium (collected at 62 stations) and 595 samples for tritium (at 60 stations). A special calibration cast was made in the Drake Passage in which all water bottles were closed at a depth of 3000 m. The water obtained is supposed to be free of CFCs, so that the overall blank can be checked. Apart from the apparatus blank, the blank of each individual water bottle is important for the evaluation of the data. On the cruise Meteor 11/5 In 1990 the CFMs F11 and F12 were not found. Now however, these CFMs could be detected in concentrations of 0.04 pmol/kg (F11) and 0.02 pmol/kg (F12). Only Freon-113 could not be detected (limit of detection: 0.001-0.002 pmol/kg) and therefore it can be concluded that the water bottles have not yet been contaminated with Freon-113. Preliminary results Preliminary data for Freon-11 are presented in Figs. 14 and 15. A quasi-zonal section from 35' E to the Greenwich Meridian is shown in Fig. 14. Between stations 12 and 18 the transition from the Circumpolar to the Weddell regime occurs. In the centre of the Circumpolar Deep Water (2000 m), the lowest concentrations (<0.17 pmol/kg) is measured, values which also occur in the Warm Deep Water at 1000 m depth and indicate older water with little renewal. The section from 55' S to Antarctica along the Greenwich Meridian is presented in Fig. 15 (top). This section can be compared with results from a previous cruise (ANT X/4, 1992). For example, the 0.2-pmol/kg isoline in the centre of the gyre at 62' S now reaches up to 2500 m, whereas in 1992 it occurred at a depth of up to 4000 m. The increase of the tracer concentration in the interior is consistent with upwelling in the Weddell gyre. On the slope of the North Weddell Ridge, bottom water with F11 > 0.5 pmol/kg is advected from the Antarctic Peninsula. Fig. 15 (bottom) shows the section across the southern Weddell gyre from Kapp Norvegia to the Antarctic Peninsula (Joinville Island). Along the slope of the Antarctic Peninsula, the newly formed bottom water is obvious from the high concentrations. Between 500 and 2000 m depth, a CFC-11 - minimum (<0.15 pmol/kg) is indicative of relatively old water. In the depth range 300 to 1500 m, an inflow of Warm Deep Water in the Weddell basin occurs at Kapp Norvegia and the outflow of this water mass is obvious on the western side. At 3000 m, a tongue of fresh water stretches from the eastern slope into the central basin. This is an indication that the centre of the Weddell basin is also ventilated from the east. On the eastern continental slope, a core of young water (>0.5 pmol/kg) occurs at 4000 m. A similar core is present on the Greenwich Meridian section in 3000 m. This indicates that the source of this water is in the Enderby basin or even further to the east. 2.3 Marine chemistry 2.3.1 The carbon dioxide system in Antarctic waters (Mario Hoppema (AWI) and Michel Stoll/NIOZ) Objectives Modifications of the global carbon cycle, by the burning of fossil fuel and changes in land use, have led to an increase in atmospheric carbon dioxide (C02) which has the potential to increase the greenhouse effect of the atmosphere. The deep oceans are, in principle, able to take up almost all of this excess C02, but only on a time scale which is much longer than the one associated with the anthropogenic perturbations. This is related to the typical mixing and residence times of the deep and bottom waters of the oceans, which are of the order of 1000 years. Thus studies in areas where interactions between the deep and the surface ocean occur, such as the Weddell Sea, are vital for the study Of C02 uptake and its distribution. An objective of this project is to gain knowledge of the C02 distribution in the Weddell Sea, where the initial properties of a major part of the abyssal world oceans are generated. Another objective is to determine the potential of Antarctic waters to take up atmospheric C02. This is especially important for the frontal regions of the Antarctic Circumpolar Current (ACC) and for the regions with seasonal ice cover. Data from this cruise will be combined with data of previous cruises to address those questions The ensuing C02 database of the Weddell Sea and the Antarctic Circumpolar Current may also be used in a modelling effort in which carbon transport and airsea gas exchanges are calculated. Work at sea The C02 system has been investigated along four sections. Section I ran from Cape Town (SA) to 55'S 39°E, section 11 across the northeastern Weddell gyre from 39°E to OOE, section III along O°E and section IV from Kapp Norvegia to Joinville Island the western Weddell gyre. Measurements of the C02 system in the entire water column were performed. TC02 (total inorganic carbon content) was determined by a high-precision coulometric method and automated sample stripping system. Briefly, the method is as follows. A sample of seawater is acidified with phosphoric acid and stripped with high purity N2 gas. The carrier gas plus extracted C02 is passed through a solution containing ethanolamine and an indicator. This solution is electrochemically back-titrated to its original colour and the amount of Coulombs used is equivalent to the amount of C02 in the sample. Data obtained were processed onboard and calibrated against an internationally recognized TC02 standard (Dickson). Continuous measurements of the partial pressure Of C02 (PC02) in water and marine air were done using an infrared analyzer (Li-Cor). A continuous water supply is passed through an equilibrator where approximately every 4 to 5 minutes the headspace gas is analyzed for its C02 content, thus giving PC02 in the surface water. Marine air was pumped continuously from the crow's nest into the laboratory and subsampled after every fourth equilibrator reading. The equipment was calibrated with reference gases, traceable against NOAA standard gases. The data obtained were processed onboard. Final data will be available pending recallbration of the reference gases ashore. Preliminary results Total carbon dioxide In Fig. 16, the section on the Greenwich Meridian is shown for TC02. The boundary between the Antarctic Circumpolar Current and the Weddell gyre regime lies at approximately 55-56°S. Generally, TC02 is low in the surface layer due to phytoplankton which utilizes C02. Below the thermocline, a TC02-maximum is found, associated with the temperature maximum of the Warm Deep Water. Near the bottom, where Weddell Sea Bottom Water is present, relatively low TC02 values were measured. This water mass originates partly from the shelf waters of the Weddell Sea, which are low in TC02. The large water volume of Weddell Sea Deep Water, which lies between the bottom water and the Warm Deep Water, is merely a mixture of these two source waters with corresponding TC02 values. The TC02 maximum is higher in the north (58-63°S) than in the south (66-69°S) and in addition is shallower in the former region. This division coincides with the cold and warm regions of the Weddell gyre, which are defined by the value of the temperature maximum. In the southern warm regime, the Warm Deep Water present has entered the Weddell gyre relatively recently. In its source area, the Antarctic Circumpolar Current, TC02 increases with depth. In the deep Weddell Sea, on the other hand, TC02 decreases with depth and thus a TC02 maximum is formed at the depth where the new Warm Deep Water meets the deep Weddell water. This deep TC02 maximum is observed at about 1500 m (66-69°S). In the northern, warm regime, Warm Deep Water is found which has already been circulating for a longer time in the Weddell gyre. The observed TC02 concentration is higher than in all waters of the warm regime and, since the Warm Deep Water is essentially the only source of water of the Weddell gyre, this implies that C02 enrichment has occurred in the Weddell Sea. In the bottom layer at 60-63°S, a TC02 minimum was observed. This is probably due to the meeting of spatially separated bottom water masses with different TC02 content. Over the flanks and the crest of Maud Rise, TC02 values were different than to the north and south. For example, the 2255-ppm isoline, which normally occurs near the bottom of the thermocline, reaches much deeper to about 800 m. The deep TC02 maximum, characteristic for the warm regime, is also less pronounced over Maud Rise. Toward the Antarctic continent (about 69°S) the isolines fall precipitously indicating a sharp frontal structure. This front separates the warm regime from the coastal regime. Partial pressure Of C02 The measurement Of PC02 along the four sections resulted in a large, high spatial resolution data set. Along Section 1, near-saturation values are generally observed, somewhat modified by the local hydrographic variations with a slight oversaturation in the south. Section 11 starts with an oversaturation and decreases to undersaturation. On crossing the frontal system between Antarctic Circumpolar Current and the Weddell Sea, an increase of about 15 ppm is observed. The section along O°E (111) is discussed in more detail (Fig. 17, top). A slight undersaturation is observed between 50 and 52°S. Then, going southwards, a sharp increase in the PC02 (about 10 ppm relative to atmospheric value) occurs, accompanied by a pronounced decrease in sea water temperature. Further south (about 56°S), the Weddell Front is characterized by a further increase in PC02 to values of 375 ppm. Regional hydrographic variations in the cold water regime of the Weddell Sea are reflected in the PC02 signal. In some areas the chlorophyll content is relatively high (65°S), which may be reflected in the PC02 signal (Fig. 17, bottom). However, the major influence on the observed signal appears to be water temperature (Fig. 17, top). The cold water regime is generally characterized by oversaturation. The subsequent decrease in PC02 concentration, to equilibrium values and below, is correlated with crossing into the warm water regime. On the flanks and the crest of Maud Rise, the water column is different in structure. This might be reflected in the PC02 as shown by the steep gradients over the flanks. Generally, the warm water regime is characterized by undersaturation. For the first time, the PC02 was measured on a long transect with ice-covered water (section IV: Kapp Norvegia - Joinville island). The newly designed water inlet on the box-keel ("Kasten kiel") made a fairly uninterrupted water supply possible. Also a slight modification to the equilibrator shower head was necessary. The observed undersaturation in PC02 (-10 to -15 ppm) is very likely caused by rapid cooling of the water which, after freezing, is prevented from equilibrating with the atmosphere. Only on nearing Joinville Island, where multi-year ice is found, oversaturation with higher values is observed (+20 ppm and over). This is caused by the upwelling of deep water, which is enriched in C02, into the surface water. During the next spring, when the ice cover retreats, phytoplankton will most likely use this excess C02 for growing. 2.3.2 Nutrient distributions in Antarctic waters (Karl Bakker/NIOZ, Michel Stoll/NIOZ and Mario Hopperna/AWI) Nutrient concentrations of silicate, phosphate, nitrite and nitrate were determined in all samples taken from the rosette. They were analyzed by a standard colorimetric method on a rapid flow "TRAACS" autoanalyzer (60 samples/hr) manufactured by Technicon. A standard range was used for all measurements (Tab. 4), while daily diluted stock standards were used for calibration. As a reference standard a socalled "cocktail" (100 fold diluted) containing a mixture of phosphate, silicate and nitrate was used. This standard was measured for statistical purposes and corrections on the data. The precision for the different properties are given in Tab. 4. Tab. 4: Standard measuring ranges used for Si, P04, N02 and N03 and standard deviations. Range (µmol/l) STD -------- ---- Silicate 0-145 0.5 Phosphate 0-3 0.03 Nitrite 0-2 0.01 Nitrate 0-40 0.21 Preliminary results As an example for the nutrient data obtained, four silicated sections are presented (Figs. 6 to 9). Generally, the nutrients are relatively low in the surface layer because of biological activity. In the Warm Deep Water below, phosphate and nitrate show a maximum, associated with the temperature maximum. Both decrease towards the bottom. The silicate maximum occurs deeper than the phosphate and nitrate maxima. It originates from the dissolution of biogenic silica, which takes place at a lower rate than the remineralisation of soft tissue, by which phosphate and nitrate are released. In the eastern part of the section, the Warm Deep Water that entered the Weddell gyre relatively recently is recognizable by a phosphate maximum at 1000-1500 m. This structure is a continuation of the same structure on the Greenwich Meridian. Remnants of it can also be seen in the very west of the basin (200-400 km), indicating that the Warm Deep Water crosses the entire basin. In the centre and west, the phosphate maximum is shallower and has a higher value. This area is comparable with the cold regime on the Greenwich Meridian. High phosphate and nitrate values are caused by sub-surface remineralization of biological material that sinks down. For silicate (Figs. 6 to 9) some specific features can be observed which cannot be detected in other tracer distributions. In the easternmost part of the section, the highest silicate values are found in the bottom layer. This may be due to an inflow of bottom water from the Enderby basin in the east, where silicate enrichment of the bottom layers is known to occur. In the central and western basin, bottom silicate values are much lower due to the presence of bottom water recently produced in the southern and western Weddell Sea. On the western slope, some young bottom water is identified by its very low silicate, phosphate and nitrate values. Earlier data showed that this band of low silicate did only reach the lower slope (until approximately 300 km of the section; Fig. 9). During this cruise, another cell of young bottom water (Si < 100 µmol/kg is found at the base of the continental rise (about 600 km), much further down the slope than during previous observations. A very interesting new observation on this transect is the major silicate- minimum structure between 2500 and 4000 m, extending over the entire eastern part of the basin. Relatively low silicate values in the deep Weddell basin are associated with bottom water which indicates that significant ventilation of the deep Weddell Sea does not only take place via the bottom route, but also via the deep water route. Since such a silicate minimum can only come into existence when the deeper water shows an increase of silicate, this suggests that this deep ventilation originates from the east where the bottom layer has a high silicate concentration. The western boundary of this deep ventilation area appears to be visible in the phosphate distribution as well as a sharp, deep phosphate front at 1000- 1100 km. 2.3.3 Tracer-Ozeanographie (Prof. Dr. Wolfgang Roether - Principal investigator) Universitaet Bremen, FB1 P.O. Box 330 440 28334 Bremen Phone: 0421 218-3511 or -4221 Fax: 0421 218-7018 Email: wroether@physik.uni-bremen.de Dr. Birgit Klein - contact for questions about measurement and data processing adress as above Phone: 0421 218-2931 Fax: 0421 218-7018 Email: bklein@physik.uni-bremen.de 2.3.3.1 CFCs: CFC11, CFC12, CFC113 and CCL4 have been measured on the cruise. A capillary column (DBVRX) was used. A Bremen-CFC standard has been used during the measurements which has been calibrated against the SIO93 scale. CFC measurements have been assigned individual errors. During the cruise a degasing of water samples was observed during the measurement process. The outgasing was corrected for F11 and F12, F113 additionally suffered from overlapping peaks of methyliodid in the chromatograms and could not be corrected for the degasing. A higher error has been assigned. The overall performance is described below: Reproducibility: F-11: 0.4% or 0.0015 pmol/kg (whichever is greater) F-12: 0.4% or 0.0014 pmol/kg (whichever is greater) F-113: 1.0% or 0.0003 pmol/kg (whichever is greater) CCl4: 0.8% or 0.0056 pmol/kg (whichever is greater) Precision: F11: 0.0475 pmol/kg or a relative error of 0.80% referring to conc. greater 1.0 pmol/kg and 0.0035 pmol/kg for conc. <1.0 pmol/kg F12: 0.0265 pmol/kg or a relative error of 0.91% referring to conc. greater 1.0 pmol/kg and 0.0030 pmol/kg for conc. <1.0 pmol/kg F-113: 0.0083 pmol/kg or a relative error of 2.0 % referring to conc. greater 0.05 pmol/kg and 0.0007 pmol/kg for conc. <0.05 pmol/kg CCl4: 0.0418 pmol/kg or a relative error of 0.7% referring to conc. greater 1.0 pmol/kg and 0.0037 pmol/kg for conc. <1.0 pmol/kg Mean water blank, detection limit: 2.3.3.2 Helium: Helium samples were taken in the usual manner with pinched-off copper tubes. After the gas extraction in Bremen the samples were measured in the laboratory with specialized noble gas mass spectrometer. All samples were calibrated using an air standard (regular air). Helium samples still have to corrected for tritium decay during storage time, as soon as the tritium data become available. Because of the low tritium concentrations in the southern ocean these corrections (concerning only the delhe3) will be very small and mainly concern the surface waters. Helium, delhe3 and neon have been assigned individual errors. The general data quality is as follows: Relative errors: Helium: 0.20% Neon: 0.20% Delhe3: 0.22% These errors were estimated using 10 pairs and one set of 4 duplicates. 2.3.3.3 Tritium: Tritium samples have also been taken from our lab during the cruise. The data are still awaiting measurement and will be submitted later. 2.3.4 Marine Organic Chemistry (Anneke Mühlebach, Andreas Zimmermann/AWI) Objectives and methods The organic chemistry work aimed to determine the distribution of dissolved and particulate phytosterols in the Weddell Sea (autumn situation). This study will complement earlier studies undertaken in the western Weddell Sea during the spring bloom of phytoplankton (ANT X/7). The objective is to understand the fate of phytosterols and other trace organic compounds in the ocean, starting with their biosynthesis and input into the euphotic zone and their possible deposition in the bottom sediments. By choosing some well defined classes out of the pool of organic compounds, the processes appearing on a molecular level can be examined. This may yield further information about the stability of highly diluted dissolutions. Water samples (20 1 each) were taken along three sections and at various depths by a rosette water sampler joined to a CTD-probe. Dissolved and particulate parts were separated by filtration. Filtration was performed over glass fibre filters (GF/C, diameter 4.7 cm, retention rate 90% for particles > 1.2 µm; for larger volume samples (vol.> 20 1), diameter 15 cm). Filters were put in ampoules and test tubes respectively, covered with inert gas (argon) to prevent oxidation, sealed and stored at -30°C. After filtration, the seawater samples were spiked with Cholesterol-d6 as an internal standard. The dissolved lipophilic compounds were extracted with hexane. A volume of 20 1 of sea water was shaken with 100 ml hexane. These extracts were put in ampoules, covered with argon, sealed and kept at -30°C. In Bremerhaven, further preparation and analysis of the samples will take place. Filters will then be extracted with acetone. Hexane and acetone extracts will be evaporated. After derivatisation yielding trimethylsilyethers, the phytosterols will be analysed by GC/MS. Concentrations in the lower (ng phytosterol)/ (I seawater) range are expected (for deep water). The quality of the extraction and the further processing is checked by the addition of various internal standards (stable isotopes). Before the extraction, 200 ng Cholesterol-d6 in 1 ml ethanol were added to the water sample. Surface samples were spiked with 2000 ng, since in surface samples higher sterol concentrations are expected. The hexane used for extraction was spiked with benz(a)anthracened12 to determine the hexane recovery (200 ng/100 ml). Just before the injection into the GC/MS system, a deuterated decachlorbiphenyl standard will be added to the sample to check the performance of the instrument. Samples taken during the cruise Section 1 part a (stations 3 to 16) from Conrad Rise to the southwestern Indian Ridge: Six profiles were taken, three at the slope of the Conrad Rise (stations 3,5,7), one in the centre of the basin (station 10), and two at the slope of the Southwest Indian Ridge (stations 14,15). At each station, seven samples (20 1 each) were taken. Samples were taken close to the bottom, 100 m above bottom, 600 to 800 m above bottom, at about 1500 m depth, at the temperature maximum (Circumpolar Deep Water), at the temperature minimum (Winter Water), and at the surface. All samples except the surface samples were taken from the rosette water sampler. The surface sample was provided by the Klaus-pump. Section 1 part b (stations 16 to 31) along the northern Weddell gyre: Five profiles were taken at a separation of 180 sm, starting at station 19 (stations 19, 22, 25, 28, 31). Again, seven samples were taken at each station. Samples were taken close to the bottom, 100 m above bottom, 600 to 1000 m above bottom, at 2500 m depth, at the temperature maximum and minimum, and at the surface. Polar and Weddell Front: Profiles were taken at both station 33 (Weddell Frontal) and station 34 (Polar Front). These samples are not influenced by the Weddell regime and the newly formed bottom water respectively, and can serve as a reference. Section 2 along the Greenwich Meridian (stations 35 to 67): 11 profiles (each some 7 samples) were taken along the section from 55°S to the continent. Four of the profiles were situated close to Maud Rise (one at the northern edge, one at the southern edge, two at the shallowest points we crossed). Between the North Weddell Ridge and Maud Rise, samples were taken every 120 sm close to the bottom, 100 m above the bottom, at 4500 m depth, at 2500 m depth, at the temperature maximum and minimum as well as at the surface. Every 60 sm, an additional surface sample was taken (Klaus-pump). On the slopes and above Maud Rise in shallower water, the station separation decreased, additional samples were taken from 1000 m depth. Profiles were taken at stations 35, 38, 44, 48, 52, 54, 56, 57,60,62,66. Section 3 western Weddell Sea (stations 69 to 103) from Kapp Norvegia to the Antarctic Peninsula: Samples were taken at the following depths: close to bottom, 100 m above bottom, 3000 m, 1500 m, 500 m, temp. maximum, and at the surface and 40 m, respectively. Profiles were taken at stations 69, 71, 75, 79, 83, 86, 90, 94, 99, 101, 102, 103. Additionally samples were taken close to the bottom at stations 95, 96, 97, 98, 100. In the newly formed bottom water, relatively high sterol concentrations may be found depending on the contact of the water mass to the open sea and on the half life of the sterols. In addition, sterols may be extracted from the sediment into the overlying water. The data gathered on section 3 may be compared to data from a former study along this track (ANT X/7). Then, a region with very low sterol concentrations was found in the central basin (concentration of brassicasterol < 0.5 ng/l, for example). This observation will be verified by samples from this cruise. Along each section, various surface samples with a volume of 80 1 were taken (Klaus-pump). This will allow the identification and quantification of sterols present in trace amounts in seawater. In addition, various experiments were performed to improve the methods applied, especially with respect to the recovery of the internal standard Cholesterol-d6. 2.4 Marine Biology 2.4.1 Plankton investigations (Anke Bittkau, Corinna Dubischar, Jochen Nowaczyk/AWI), Vassili Spiridonov/ZMMU) Objectives and methods Zooplankton and micronekton distribution in the Weddell gyre depends largely on oceanographic structures in this region. During ANT XIII/4, two main questions were addressed by our planktological studies: 1. How are horizontal and vertical distributions of zooplankton and micronekton determined by the different oceanographic regimes in the Weddell Sea (i.e.: the frontal system between the Antarctic Circumpolar Current and the Weddell Sea; the warm regime; the cold regime, and the coastal current) ? 2. How do the dominant zooplankton and micronecton organisms switch to overwintering modes in these different regimes? To answer these questions, our studies focused mainly on phytoplankton, zooplankton and micronekton species composition, abundance and distribution as a function of oceanographic structures. For precise measurements of the vertical distribution of larger zooplankton and micronekton, an Optical Plankton Counter (OPC) was used in addition to the net catches. This OPC was attached directly to the multinet. The continuous photometric measurement of particle size and number enables us to assess particle distribution parallel to the multinet-catches with a high resolution. In the following section, the methods used, as well as some preliminary results will be described in more detail. Phytoplankton distribution Chlorophyll a determination: Phytoplankton biomass in the water can be detected by fluorometric measurement of the phytoplankton pigment chlorophyll a (Chia). Two different approaches were used: 1. Underway surface (8 m water depths) fluorescence of phytoplankton pigments (expressed as chla) was recorded by means of a Turner Design JD 10) fluorometer attached to the seawater system with the ship's membrane pump. Data were obtained every 10 seconds and averaged in 5 min intervals and subsequently stored on the ship's data logging system (POLDAT) together with the appropriate ship's position and other physical, chemical and meteorological data. Every 4 hours, and also at the stations, triplicates of normally 1 1 of seawater, but occasionally more (drained from a bypass to the fluorometer system), were filtered onto Whatman GF/F glassfibre filters for calibration of the instrument. The chla and phaeopigment values were obtained after extraction with 90 % aceton/water. The determination limit was 0.001 µg chla/l. 2. At stations Cchlorophyll a measurements were done from the Niskin bottles of the CTD rosette. At 49 stations, water from 20, 40, 60, 80, 100 and 200 m was taken. if OPC measurements and multinet samples indicated high particle concentrations in deeper water layers, additional samples were taken from water depths down to 500 m. Along the transects 3 and 4, chla-concentrations in the < 20 µm and the >20 µm size fraction were measured separately. To determine the chla-concentrations, 2 1 of seawater were filtered onto Whatmann GF/F-glassfiber filters. Pigments were extracted with 10 ml 90% acetone and measured thereafter directly on board using the method by Evans et al. (1987). Parallel to the sampling for chla measurements, 2 1 seawater per depth level were filtered onto precombusted (24 h at 500°C) Whatmann GF/F-filters for later analyses of particulate organic carbon and nitrogen (POC/PON). These filters were deepfrozen (-20°C). Measurements will be carried out at AWI using an Carlo-Erba CHN Analyzer. For determination of phytoplankton concentration and species composition, 200 ml of seawater were taken from the same depths as for chla and POC/PON-measurements and fixed with hexamethylentetramin-buffered 20% formalin (end concentration 0.6%). These samples will be processed using the Utermöhl-counting technique (1958) at the home laboratory. Additional samples were taken with an Apstein-net (mesh size 20 µm) to concentrate larger phytoplankton from the upper 10 m of the water column. Zooplankton and micronekton distribution Zooplankton organisms were sampled using a Multinet (Hydrobios, Kiel) with mouth opening of 0.25 M2 and mesh size of 100 µm. An OPC was mounted on the net frame. The OPC photometrically records the distribution and size of particles in the water column. Each half a second, the data are transferred to the deck unit, yielding in an exact pattern of the vertical distribution of plankton organisms parallel to the multinet tow. The multinet was towed with a speed of 0.5 m sec- 1. At all stations, the multinet tows were conducted down to 1000 m (or in the shelf areas nearly to the bottom). Five depth strata were chosen according to the thermohaline structure of the water column. In total, 31 successful multinet stations were performed: 3 stations on the zonal transect along 54°S (transect 2a), 6 on the transect across the Weddell cold regime (transect 2b), one station in the Polar Front, 12 on the transect along the Greenwich Meridian (transect 3), and 9 stations on the transect across the western Weddell Sea from Kapp Norwegia to the Antarctic Peninsula (transect 4). After towing, each sample was split into 2 subsamples using a 2 1 Folsom splitter. One half was immediately preserved in 4% hexamine buffered formalin, while another was used for size fractioning and subsequent preparation for biomass measurement. Before fractioning, we checked a subsample for rare or taxonomically interesting specimens. Simultaneously, several specimens of the dominant species (mostly Calanoides acutus, Calanus propinquus, and R. gigas) were selected for the determination of carbon and nitrogen (C,N) content and ratio, and fatty acids composition of lipids. For biomass measurement, a subsample was screened subsequently through 2000 tm, 1000 µm, 500 µm, 200 µm, and 100 µm meshes. Each of the fractions obtained was then filtered onto preweighted GF/C filters and dried at 500C for 24 h. In case of the presence of abundant phytoplankton, subsamples for biomass determination were not fractioned but preserved in formalin separately. Zooplankton biomass in these samples will be estimated from size spectra of major taxa using length/weight regressions. Salps from the biomass subsample were measured and dried on filters or deep frozen separately according to a size grouping. For determination of C,N content, the organisms were identified, staged and measured under a stereomicroscope with an accuracy of 0.1 mm, rinsed in distilled water and deep frozen individually (or for young copepodite stages of large calanoids in groups of 2-3 specimens) in Eppendorf caps. Measurements will be carried out using a Carlo Erba CHN analyzer. For the study of fatty acids composition of body lipids, we selected 3 to 5 specimens of particular developmental stage of certain species and placed them into precombusted tubes with 10 ml conserving solution (Dichlormethan/methanol in a proportion of 2:1). These tubes were then stored under -20°C. Micronekton was collected using a Rectangular Midwater Trawl with two nets, the larger one with an mouth opening of 8m2, the smaller one with an opening of 1 m2 (RMT 1+8) which was towed obliquely from the depth of ca. 450 m to the surface. The volume of water filtered was estimated using flowmeters mounted in the mouth of both nets. Four RMT tows were performed on transect 2b across the Weddell cold regime waters, 7 tows were done on the Greenwich Meridian (transect 3) and one additional tow was performed in the Bransfield Strait. The fresh catch of the big (8 m2) net was sorted into major taxonomic groups, i.e. coelenterates, polychaets, pteropods, cephalopods, euphausiids, hyperiids, decapods, chaetognaths, thaliaceans and fishes, which were preserved in 4% formalin and later counted. The sample of the small (1 m2) net was preserved without sorting. Further processing of the RMT samples will be done in the AWl and the Zoological Museum of the Moscow University. Several vertical Bongo net (200 µm and 500 µm mesh size) tows were performed in order to obtain alive animals for experiments and for further DNA/RNA analyses. Preliminary results In the following section, the results of the on-line chlorophyll measurements during the transects 2a, 2b and 3 are shown. Because of the permanent ice cover during transect 4, no surface chla data are available. Table 5 gives some general information concerning the positions etc. of the transects. Table 5: Characterization of the transects carried out during ANT X111/4. Date Station Position Start Position End Name ----------- ------- -------------- ------------ ---------- 17.3 - 23.3 01-02 Cape Town 54°00.0'S Transect 1 38°59.8'E 23-3 - 28.3 03-15 54°00.0'S 54°00.0'S Transect 2a 38°59.8'E 25°44.4'E 28.3 - 05.4 15-32 54°00.0'S 59°27.5'S Transect 2b 25°44.4'E 3°10.5'W 12.4 - 22.4 35-66 55°00.0'S 69°38.5'S Transect 3 0° W 0°07.4'W 25.4 - 08.5 68-102 71°01.0'S 63°20.1'S Transect 4 11°36.6'W 52°47.6'W Transects 2a/2b: In general, very low chla concentrations were measured during both transects, which was in accordance to expected values during late autumn in this area (Figs. 18 and 19). Background values were between 0.1 and 0.2 µm Chla/I. On transect 2a, a distinct chla maximum was measured between 290 und 30°E, east of a significant increase of surface salinity and a decrease in surface temperature. Further to the west, an increase of the chla-concent ration to a maximum value of about 0.5 µm/l was detected. These relatively high concentrations persisted in the connecting transect 2b between 25°E and 19°E. These positions coincide with the site of an extensive frontal system in this region. Further analyses of phytoplankton composition and detailed investigations on hydrographic conditions are needed to detect possible reasons for this higher phytoplankton biomass. Transect 3: Transect 3 followed the Greenwich Meridian from 55°S to the ice shelf edge. During this transect, very low chla-concentrations were found (Fig. 20). Chlorophyll aconcentrations in the north were higher than those further south. Two maxima at about 60°S are particularly noticable. Further investigations of, for example, phytoplankton species composition are needed to explain these patterns. Fig. 21 shows some of the vertical profiles registered by the OPC attached to the multinet. The particle concentrations showed very pronounced peaks in the upper water layers (ca. upper 150 m), but varied significantly between the different profiles. Generally the particle concentrations of up to 12000 particles m-3 were surprisingly high. Further investigations of the multinet catches will reveal the characteristics of the particles. Sediment traps Some of the particles produced in the upper ocean layers, e.g. phytoplankton aggregates and faecal pellets, may reach relatively high sinking velocities, leading to their sinking out of the surface layers. Sediment traps have been attached to the following moorings to assess this particle flux qualitatively as well as quantitatively: 227/2, 227/3, BO-5, BO-6 and PF-8. These sediment traps are equipped with 20 Tab. 6: Recovered sediment traps: Mooring: 227/2 at 59°27.5 S and 3°11.2 E deployed on 26.12.1994 recovered on 05.04.1996 Depth of the trap 565 m 3709 m Time of deployment 27.12.1994 - 10.08.1995 27.12.94 - 11.01.96 Sampling interval 19 days 19 days Number of samples 115 20 Mooring: BO-5 at 54°20.6 S and 03°17.6 W deployed on 27.12.1994 recovered on 07.04.1996 Depth of the trap 531 m 2268 m Time of deployment 31.12.1994 - 15.01.1996 31.12.1994 - 08.12.1995 Sampling interval 19 days 19 days Number of samples 20 18 Mooring: PF-8 at 50°11.1 S and 05°53.7 E deployed on 29.12.1994 recovered on 09.04.1996 Depth of the trap 687 m 3110 m Time of deployment 31.12.1994 - 15.01.1996 31.12.1994 - 15.01.1996 Sampling interval 19 days 19 days Number of samples 20 20 Table 7: Newly deployed sediment traps: Mooring: 227-3 at 59°01.8 S and 0.0° E deployed on 04.04.1996 Depth of the trap 3373 m Time of deployment 06.04.1996 - 27.03.1997 Sampling interval 14 days Mooring: BO-6 at 54°20.6 S and 3'17.0 W deployed on 07.04.1996 Depth of the trap 2280 m Time of deployment 08.04.1996 27.03.1997 Sampling interval 14 days sampling containers and are therefore able to collect the sinking material in 20 different time intervals. To prevent degradation of the material in the sediment trap by microbial activities and zooplankton grazing, the sampling containers were poisoned with mercury dichloride. The deployed and recovered sediment traps are summarized in Tab. 6 and 7. 2.4.2 Benthos investigations (Wolf Arntz (AWI, Alexander Buschmann/AWI, Kai Horst George/FBZO, Dieter Gerdes/AWI, Matthias Gorny/AWI, Marco Antonio Lardies Carrasco/UACH, Katrin Linse/IPO, Americo Montiel/UMAG, Erika Mutschke/UMAG, Martin Rauschert/AWIP) and Carlos Rios/UMAG) Objectives During the second part of the cruise, the investigations carried out by RV "Victor Hensen" in October/November 1994, were continued to study the marine fauna and flora in the Magellan region to compare it with Antarctic conditions and to detect latitudinal clines In population dynamics, reproductive biology and other life strategy components from the high Antarctic to the Strait of Magellan. These two areas separated only recently In geological terms (<20 Ma) and are supposed to have had more intense interchange than other continents around the Antarctic. In addition they should have had a similar history of glaciation. Faunistic and floristic overlaps have often been suspected between the Antarctic Peninsula and the Magellan region, which essentially comprises Patagonia and Tierra del Fuego with their vast system of channels and fjords. This view seems to hold true for some faunal groups, however it cannot be confirmed for other taxa, or at least there are major doubts. The principal reason for these uncertainties is the lack of adequate sampling in the Magellan region and on the adjacent continental slope of the Drake Passage. In the past years major efforts have been made to improve the knowledge on both the Antarctic and Magellan fauna and flora. From recent work at the "Dallmann" laboratory, an annex to the Argentinian base Jubany, and other stations shallowwater fauna and flora in the Bransfield Strait near King George Island are fairly well known. During the "Joint Magellan 'Victor Hensen' Campaign 1994" substantial samples were taken in shallow and deep waters of the Strait of Magellan (to 650 m depth), in the northwestern branch of the Beagle Channel and south of the eastern entrance of the Beagle Channel down to Cape Horn. The preliminary result of that cruise was that the ecosystems on the two sides of the Drake Passage, despite certain coincidences in common faunal and floral groups on genus and species levels, have developed very distinct structures. The original idea to fly the seven German and four Chilean participants plus two Chilean observers to King George Island failed because of bad weather, and "Polarstern" was ordered to Puerto Williams to pick up the participants on Navarino Island. Thus the activities had to be restricted to the northern slope of the Drake Passage (south of Nueva Island), leaving the intended work in the Bransfield Strait and the southern slope of the Drake Passage to a future cruise. With the reduced programme on the northern slope of the Drake Passage, the benthos group pursued the following objectives: … To assess the macro- and meiofaunal zoobenthic structures on the northern slope of the Drake Passage and the south Chilean shelf, using gear that had been deployed formerly in the high Antarctic, off the Antarctic Peninsula and in the Magellan region; … to complement existent benthos samples by material from the areas mentioned above, above all from greater depths; … to carry out physiological, reproductive, and population dynamic investigations and ethological studies on "key species" and to compare the results with those of related species from lower and higher latitudes. Work at sea The original idea was to work on a transect between 1500 m depth on the Patagonian continental slope and 200 m on the shelf south of Isla Nueva, to complete the samples obtained during the "Joint Magellan 'Victor Hensen' Campaign 1994". Part of this transect should have been done during that expedition, but this had to be abandoned due to bad weather. On ANT XIII/4, 5 working days were available to complete the work south of Nueva. "Polarstern" encountered calm weather but, quite unexpectedly, very rough bottom topography. The layer of fine sediments, if existent, was much thinner than at the stations worked with "Victor Hensen" in the eastern mouth of the Beagle Channel in 1994. For this reason the stations, originally planned on a transect between 2500 and 100 m, had to be chosen where topography, thickness of sediments and currents allowed the use of trawled gear and corers. Even so, by no means all equipments could be deployed at all stations. The final list includes 10 Agassiz trawl (AGT) catches (2 for collecting experimental material only), 3 hauls with the epibenthic sledge (EBS), 9 catches with the small Rauschert dredge (D), 3 multibox corer (MG) stations with 21 macro and 2 meiofaunal samples, 4 multicorer (MUC) stations with 30 meiofauna samples, and 380 pictures with the underwater camera at 5 stations. A CTD rosette registered temperature, salinity and dissolved oxygen between the surface and the seafloor. A large number of macrofaunal organisms were photographed alive, and fish and crustaceans were kept in the cool containers for physiological experiments. Preliminary results All samples obtained during this cruise, except for live experimental material, were preserved (for methods, cf. cruise report of the "Victor Hensen" Campaign, Arntz & Gorny 1996) and require detailed analysis in the laboratories of the participating institutions. Definite results will be presented during the IBMANT/97 workshop to be held at the Universidad de Magallanes in April 1997. The following preliminary faunal results, based principally on the sorting of the AGT catches on deck, can be summarized at this time: A first look at the meiofauna obtained from the filtrate of the multicorer samples and from other gears revealed the following groups to occur (in decreasing abundance): nematodes; copepods (calanoids presumably from the water column, harpacticoids, siphonostomatoids); polychaete larvae; ostracods; and foraminiferans. Other groups are to be expected from further microscopical analysis of the samples. The macrobenthic endofauna of the multibox corer samples from 100 to 1200 m depth showed low densities which decreased even more with depth. At the shallower stations the seafloor was covered with a biogenic layer of shells as well as bryozoan and hydrozoan debris, and the dominant faunal elements were ophlurolds, echinoids and crustaceans. At the deeper stations, the substrate (if any) was fine sand, and the only identifiable organisms were small sedentary polychaetes. The benthic macro and megafauna from AGT and small dredge was richest in number and biomass at medium water depths between 200 and 600 m. Total catch weights in shallow water were high but consisted mainly of dead shells. The deeper seafloor in the area of study seems to be characterized by a generally thin sediment layer which resulted in a large number of gear failures and was further reflected in the dominance of hard-bottom dwellers, in particular gorgonarians. Larger stones came aboard from all depths and were often strongly overgrown with sponges, hydrozoans, bryozoans and gorgonarians whereas bivalve molluscs and brachiopods were missing on the stones altogether. On the northern slope of the Drake Passage, too, the result from the "Victor Hensen" expedition is valid that there are no such rich, three-dimensional epifaunal suspension feeding communities as in many parts of the Antarctic. However, the occurrence of sponges, bryozoans and gorgonarians revealed a distinct increase as compared with the Strait of Magellan, the Beagle Channel and the eastern mouth of the Beagle Channel, and crinoids (although small and brittle) were found only in this southernmost part of the Magellan area. The scarceness of colonial and solitary ascidians as compared with the Antarctic was confirmed, and actinians were also relatively scarce. Hydrozoans remained common south of Nueva despite the non-occurrence of its principal substrate, the brown alga Macrocystis pyrifera, due to greater water depths. Hydrocorals were found frequently on shells and stones. Asteroids turned out to be much scarcer and smaller than in the Magellan area further to the north. Regular echinoids were at about the same level whereas irregular sea urchins were of much lesser importance than further to the north, particularly in the Beagle Channel, presumably because of the scarceness of soft substrates, The great variety and abundance of ophiuroids on the shelf was further increased by the large gorgonocephalans which contribute an important share to the echinoderm biomass. The find of crinoids has been mentioned already. Molluscs, especially bivalves, played a minor role south of Nueva except for the scallops (Chlamys) which were found to be abundant at some shallower stations. The scarceness of bivalve molluscs, which resembles the conditions in the Antarctic, was unexpected after the dominance of molluscs found in the Strait of Magellan and in the eastern mouth of the Beagle Channel; however, the reason (as for the missing of scaphopods) may again be the lack of soft bottoms. Bivalve species composition was similar to the fauna further north if the taxodont soft- bottom dwellers are not considered. Among the prosobranch gastropods there were some species which had not been found in the regions further to the north. Chitons and octopods were present at a low abundance level. Brachiopods which in the Antarctic "replace" the bivalves as hard-bottom fauna, were only found in a few small specimens, contrary to our results in the Magellan Strait. The various "worm" groups can be judged only after more thorough analysis. It seems, however, that the scarceness and small size of echiurids and sipunculids stated during the "Victor Hensen" campaign was confirmed, and priapulids were missing altogether (at least on macro level). Polychaetes were common, but always small, and often colonise gorgonarians, bryozoans and hydrocorals. For the small crustaceans, there is as yet no information available since all material was preserved immediately after trawling. Among the larger forms, balanoids were by no means as common in shallow waters as further north. However, at the deepest stations a large barnacle was found which strongly resembled the Antarctic genus Bathylasma. Isopods, in particular Sphaeromatidae, were considerably less common than to the north. Arcturidae and Serolidae, dominant groups in the Antarctic, were found in low numbers but yielded some species we had not seen before. Among the amphipods which dominated the small dredge catches, all families occurred which had been registered for the Weddell Sea and the Antarctic Peninsula area, with Eusiridae, Lysianassidae and Ischyroceridae as dominant groups. Also Stilipedidae, which had never been found in the Magellan region before, were quite common. Among the amphipods and isopods there were no giant types as described for the Antarctic. The same is true for the pycnogonids, and in all three cases this is valid for the whole Magellan region. Several new types of parabioses were detected, e.g., Caprellidae among the spines of lithodid crabs and Ischyrocericlae in epizoic bryozoans (Flustra type) on majid crabs. Reptant decapods, in particular of the cancrid and sea spider brachyuran types, were no longer dominant in the area of study. The Galatheidae (Munida) still occurred regularly but were much less common than in the eastern mouth of the Beagle Channel. The palinuran lobster Stereomastis two specimens of which had been found in the Beagle Channel during the "Victor Hensen" campaign occurred in a single specimen. Caridean shrimps were gaining importance in relation to the reptants but never reached Antarctic levels. Dominant genera are Campylonotus and Austropandalus as well as surprisingly, at the deep stations, also the Antarctic genus Nematocarcinus. As rarities among the clecapods first finds of two genera, Glyphonotus and Pontophilus, have to be mentioned. Summarizing, the working area on the northern slope of the Drake Passage, south of Nueva Island, revealed a greater similarity to the Antarctic benthic fauna than the Strait of Magellan, the Beagle Channel and the area immediately south of the Beagle Channel. We might cautiously conclude that the transition to the Antarctic 'is rather of a gradual nature than abrupt. Despite this fact, considerable differences remain between the Antarctic and this southernmost part of the Magellan region. This indicates that 20 million years of separation and isolation, despite some glacial periods of increased interchange, have led to rather distinct separation of two neighbouring marine ecosystems which originally had an identical fauna. A closer look at these phenomena will be taken during the IBMANT/97 workshop in Punta Arenas. 3. Leg ANT XIII/5 Punta Arenas - Bremerhaven 22.05. - 21.06.1996 3.1 Summary and Itinerary The theme of the scientific programme of the last leg of Polarstern's 13th Antarctic expedition was 'diversity of the deep-sea fauna'. Along the ship's transect (Fig. 23) the faunistic diversity of microorganisms, zooplankton, meio- and macrobenthic organisms was investigated in order to look for any latitudinal gradients in the distribution patterns. Of special interest were the deep basins in the South Atlantic, where little work has been done to date. On five deep-sea stations, each greater than 5000 m water depth, four different corers (multibox-corer, rotating-corer, multi- and minicorer) were deployed, providing quantitative sediment samples for analysing the distribution patterns of meio- and macrobenthos. Depth-related and latitudinal distribution patterns of zooplankton were investigated by means of multinet catches from 4 stations; CTD measurements carried out first provided immediate information about the hydrographic structure of the water column at these locations. The microbial deepsea community was studied by means of a newly developed, deep water sampler which provided enriched samples of barophilic microorganisms under collection pressure by pumping and filtering a large volume of sea water in-situ. Between 47°S and 24°S, a bathymetric profile 1335 sm long was obtained from Parasound surveys, which provide analyses of the bottom topography and sediment structure. The data are stored on analog paper record and also in digital form. The multibox-corer and the rotating-corer provided a total of 28 single cores from four stations for macrobenthos analysis. Some basic work on the samples has been carried out on board but detailed analyses have to be done at the home institutions. At a first glance, the macro-benthos at the four locations under study seems to be very poor in both abundance and biomass compared to Weddell Sea samples from similar depths. The mini- and multicorers provided a total of 54 sediment cores from four stations. Eight of these were used for microbiological studies and 23 are for investigation of latitudinal diversity patterns of both nematodes and copepods. From initial examinations of the samples, we formed the impression that the meiofauna appears the same compared to other deep-sea sites further north and south. The newly developed, deep-water sampler obtained concentrated water samples from 4 stations under deep-sea pressure. These samples provide data which will form the basis for a description of the composition of the benthic microbial community structure and its biomass and will allow further insights into the existence and role of a decompression- sensitive fraction of bacteria and its biomass and activity. Temperature measurements in the mesopause of the atmosphere, accomplished with a newly developed, potassium temperature lidar system, completed the scientific work of this leg. The group from the Institut für Atmosphärenphysik in KOhlungsborn measured profiles of temperature and potassium densities between 47°S and 45°N on 18 nights and obtained unique and very interesting results about the thermal structure and densities of potassium atoms in the atmospheric layer between 80 to 105 km altitude. 4. Scientific programmes 4.1 Investigations of the atmosphere 4.1.1 Weather Conditions (Joachim England, Herbert Köhler, Edmund Knuth/DWD) During our passage through the Strait of Magellan on the night from the May 22th to 23th, the wind conditions often changed due to orographic effects. Wind strength changed on very short time periods between Force 3 to 10. During our passage, the area of the Magellan Strait lay to the rear of a storm low. Behind this disappearing low, a pronounced shallow low developed east of our cruise track, reaching far south to the Antarctic, thus keeping us away from further deep lows which came up from the west. With these conditions our passage along the Argentinian coast line took place in quite calm weather with wind strengths around Force 3 increasing occasionally towards Force 6, the main direction being west to northwest. The first station at 47°S and 55°W could thus be worked under favourable weather conditions. Above the central South Atlantic, a strong and wide-spread high developed with a pressure of more than 1040 hPa at its centre. On the other side, an association of clouds in front of the East-Brasilian coast, formed a relatively small low pressure whirl which persisted for several days, moving slowly in a northeasterly direction. From May 27th, this low pressure dominated the weather situation. Work on the second station at 38°S and 43°W was hindered by strong wind and consequently rough sea. On May 30th, the wind decreased to Force 3 to 5 backing towards a northerly direction and remaining so for the following day. On the western border of a wide-spread, strong high over the central South Atlantic, the relatively strong pressure gradient maintained northeasterly winds of Force 6 during June 1st and 2nd. On June 3rd, the wind decreased to Force 4 and the third station could be worked under good conditions. On June 4th and 5th, the wind increased again to Force 6 turning towards a southeasterly direction. During June 5th, heavy showers with gusts up to 36 kn occurred decreasing, however to Force 3 to 4 towards the evening. On June 6th, another station was worked at 4°S 27°W. The wind decreased further from Force 4 to 2, accompanied however by heavy rainfall. In the late afternoon of June 7th, we crossed the equator with winds of Force 1 to 3 from an easterly direction. Light southeasterly winds Force 1 to 3 also dominated in the area of the Intertropic Convergence Zone which we passed during June 8th, when it rained occasionally. On the morning of June 9th, the wind turned towards the northeast with Force 3 to 4. No further rain occured and weather was influenced by the northeast trades. This situation remained until June 14th. Winds of Force 3 to 4 were a regular feature from then on and the last station at 230N 24°30'W was worked under favourable meterological conditions. Between June 15th and 20th, light winds of Force 1 to 4 from different directions dominated along the ship's track. The feared Bay of Biscay and the Channel were amazingly calm this time. Approaching Bremerhaven on June 21th wind increased again to Force 6 or 7, with northern to northeasterly directions due to a deep low over Scandinavia. 4.1.2 Temperature observations in the mesopause (Matthias Alpers, Veit Eska, Josef Hbffner, Ulf von Zahn/IAPR) Objectives and methods The scientific objectives of the IAPR participation in the legs ANT XIII/4-5 have been the exploration of both the thermal structure of the atmospheric layers in the 80 to 105 km altitude, and the densities of potassium atoms residing therein. At this altitude, the atmosphere exhibits a permanent deep, local temperature minimum (the so-called mesopause). However, little is known about the precise temperatures at the mesopause and their spatial and temporal variations. This is particularly true for the southern hemisphere. The potassium atoms, present in this region, are remains from the vaporisation of micrometeorides (i.e. shooting stars) and cosmic dust. The loss processes for these atoms are unknown. Yet, there exists a permanent layer of potassium which exhibits a maximum density of about 100 atoms per cm -3 at approximately 90 km altitude. For remote sensing of the air temperature and potassium density, we used for the first time, a transportable, containerized, lidar instrument ('light radar'). It operates at the resonance wavelength of potassium at 770 nm (near infrared). From a measurement of the time which passes between emission of the laser pulse and arrival of the atmospheric echo signal in the instrument's detectors, one can calculate quite accurately the altitude of the scattering air volume. By means of a tiny modulation of the wavelength of the laser light, one can also measure the temperature of the potassium atoms between 80 and 100 km altitude. This temperature is a good approximation to the air temperature. Work at sea and preliminary results The observational programme, the data analysis and its interpretation, for legs ANT X111/4 and ANT XIII/5, all form a scientific entity for us and therefore we summarize the results obtained in both legs here. The first night of lidar observations was March 25th, the last the June 18th, 1996. Within this period lie a total of 31 nights with measurements of temperature and potassium density and an additional 4 nights with measurements of potassium density only. The excellent performance of the lidar and unexpectedly good weather contributed to these good observation statistics. Observations were made from 71°S to 45°N. Seasons changed from late autumn/early winter at high southern latitudes to "deep winter" at south-tropical latitudes and then to high summer in the northern hemisphere. For our research program, this type of variation was almost ideal. Almost all measured profiles of air temperature and potassium density are characterized by high wave activity in the upper atmosphere. This general property of the upper atmosphere is well known, but makes the determination of genuine climatological mean parameters difficult. Though in fact one just needs a very large data base. We were fortunate, therefore, to be able to obtain 4 nights of continuous observations lasting more than 12 hours plus 3 nights of more than 9 hours. These long observation series will allow us to characterize and quantify the wave spectrum and to derive corrections for the shorter observation sequences. The altitude and temperature of the mesopause was measured over a rather wide range of latitudes with high temperature accuracy and altitude resolution. We obtained new and interesting results pertaining to the latitude dependence and seasonal variations of the mesopause altitude and temperature (although we acknowledge that a clean separation of the two effects in our data will be somewhat subjective). In the southern hemisphere there are, however, no other measurements available with which we could compare our newly acquired data. Before now, potassium density profiles have been measured in the upper atmosphere in only two locations. For that reason, all of the aquired potassium data are entirely new. We observed an outstanding variation of the potassium density with latitude and a previously unobserved high occurrence rate and intensity of socalled sporadic potassium layers. An example of atmospheric wave activity showing up in the potassium profiles is given in Fig. 25. The 59 potassium density profiles, which we aquired on June 7th, 1996, between about 2 and 7 pm. (UT) near YS are shown. The temporal separation of the profiles is 4 min. The number density scale at the abcissa applies to the first left profile. Each following profile is offset to the right by a value of 10 atoms per cm-3. During this night, the normal potassium layer extended from 80 to 100 km altitude. The density profiles are modulated by the passage of waves through the background atmosphere. In addition, there are a few short-lived sporadic layers near 90 km. 4.2 Marine Biology 4.2.1 Microbiology (Erich Dunker, Elisabeth Helmke, Ulla Klauke/AWI) Objectives and methods During usual sampling of sediment or water, deep-sea organisms experience decompression. The central question of the microbiological work during this leg was whether, and if so, to what extent, such decompression affects the microbial deep-sea assemblages. The results will contribute to a better understanding, as well as to a realistic quantification, of the microbial processes in the deep- sea. A prerequisite of this study was a recently developed water sampler which concentrates particulate organic matter in-situ and brings it up to the surface maintaining in-situ pressure. Subsequent subsampling on board can be conducted without pressure loss. As well as these investigations on the existence and role of decompressionsensitive bacteria, studies of biomass, activity, and structure of the benthic microbial community from the deep sea were carried out with the decompressed sediment and water samples of the multicorer. The results will supplement our data set from the microbial flora of different deep-sea basins of the north and east Atlantic. Work at sea The pressure-retaining water sampler was deployed at four stations. Concentrated water samples were obtained under deep-sea pressure. They were subdivided and subjected to different experimental conditions. The final evaluation of these experiments will be done at the home laboratory. The same is true for the measurements and the experiments with the decompressed multicorer material. Subsamples of the sediment and bottom water were fixed and preserved for total count and biomass determinations as well as for the chemical analyses. Furthermore, growth and degradation experiments were prepared under simulated deep-sea conditions. In order to describe the structure of the benthic microbial deep-sea community, MPN-cultures were conducted. Since the MPN-cultures were subjected to different pressure and temperature conditions, a differentiation of allochthonous from autochthonous deep-sea bacteria will be possible. 4.2.2 Zooplankton (Harald Bohlmann, Birgit Strohscher/AWI) Objectives and methods Studies of mesozooplankton diversity and biomass of the whole water column were addressed by means of multinet hawls (150 gm mesh size) from 5 deep-sea stations at 9 depth intervals. Vertical and horizontal biodiversity, biomass distribution patterns and length/carbon -content relationships of different-sized specimens with species from different water depths will be established. Studies of gut content and reproductive condition of dominant copepod species completed the working programme. Work at sea CTD measurements (SEABIRD 911 plus) were carried out before the multinet was deployed in order to provide immediate information about the hydrographic structure of the water column at the sampling locations. Four profiles are displayed in Fig. 26. The multinet was successfully deployed at 4 stations. The station data are summarized in Annex 5. Samples were taken from the following depth intervals: St. Nos. 118 and 122: 3600 - 2600 m, 2600 - 2000 m, 2000 - 1500 m, 1500 - 1000 m, 1000 - 0 m with multinet No. 1 1000 - 750 m; 750 - 500 m, 500 - 300 m, 300 - 100 m, 100 - 0 m with multinet No. 2 St. Nos. 119 and 121: 3000 - 2500 m, 2500 - 2000 m, 2000 - 1500 m, 1500 - 1000 m, 1000 - 0 m with multinet No. 1 Multinet No. 2 at these stations sampled the same depth intervals as in the first two stations. All samples were carefully filtered through 100 µm sieves and preserved in a 4% formaldehhyde solution buffered with hexamethylentetramine. The 1000 - 0 m sample of multinet No.1 from each station was split into two halves by means of a plankton splitter. One half was frozen for estimating the biomass later in the laboratory, while from the other half, different species groups were sorted out on board for various analyses, e.g. Iength/carbon -content relationships and studies of gut content and maturity stage. The detailed analyses of the material obtained has to be done at the home institution. 4.2.3 Meiobenthos (Nicola Jane Debenham/NHM, Timothy John Ferrero/NHM, Pedro Martinez- Arbizu/FBZO, Gisela Silveira Moura/FBZO) Objectives and methods Recent studies have indicated the importance of the deep sea as an environment of high species diversity. Latitudinal diversity gradients in the South Atlantic are poorly studied and seem to be highly influenced by interregional variation and regionalhistorical processes. Patterns of diversity from the North Atlantic have been mainly derived from macrofauna and nematode studies. Only a few studies deal with other groups like foraminiferans and copepods. Our planned study will give us a first indication of latitudinal deep-sea diversity patterns in the South Atlantic. Low abundances and high variability are expected in the deep-sea, therefore a high number of replicates is needed. Quantitative samples were taken with the Multicorer. The scope of the work is to undertake a latitudinal study of meiofauna abundances, their spatial distribution and their diversity. This allows us to correlate these parameters of the benthic fauna with surface productivity at the different stations. This work provides valuable information on the Southern Atlantic and is invaluable for comparison with data from the Madeira Abyssal Plain, Porcupine Abyssal Plain, and Arctic Ocean (Barents Sea, Laptev Sea) in the North Atlantic, and some Antarctic sampling sites in the Weddell Sea. It is hoped that the data will enable an assessment of the biogeographical range and species turnover rates of abyssal meiofauna, particularly nematodes and copepods. Work at sea In total, four stations were successfully sampled with the Multicorer (MUC). Two of these stations were additionally sampled with the Minicorer (MIC). An overview of the sampling regime is given in Tab. 8. The area sampled by each corer covers about 25 cm2. The individual corers in the MUC were numbered and their position in the gear documented, so that the relative distances between replicates can be determined. Tab. 8: Material and treatment; A: for microbiology, B: sliced for meiofauna, C: homogenisation technique for meiofauna studies and biochemistry Station No. Depth MUC/MIC Treatment ---------- ------ ------------- ------------ 40/118 5726 m Muc 11 corers 2 x A, 9 x B 40/119 5095 m - 40/120 5130 m Muc 12 corers 2xA, 10xB 40/121 5366 m Muc 12 corers 2xA, 10xB 40/122 5055 m Muc 11 corers 2 x A, 9 x B 40/121 5362 m Mic 4 corers 2 x B, 2 x C 40/122 5102 m Mic 4 corers 2 x B, 2 x C For the study of the melofauna (treatment B) the cores were sliced in 6 sections. The first section includes the first centimetre of sediment (0-1 cm) and the overlying bottom water, the remaining sections were 1-2 cm, 2-3 cm, 3-4 cm, 4-5 cm and 5-10 cm. Samples were fixed with buffered 4% formaldehyde in filtered seawater. Homogenisation technique (treatment C): Cores were sectioned to 5 cm in 1cm horizons. Each section was homogenised to a semi-liquid state with the addition of artificial seawater and the resulting homogenate divided into two equal subsamples. One sub-sample will be for meiofauna studies and the other for sediment biogeochemical analysis (mainly lipids and proteins) at the University of Liverpool, Dept. of Oceanography. Preliminary results The sediments at the four stations sampled are very different. At Station No. 40/118, in the Argentinian Basin the sediment has a significant sandy component and gravel is also observed. Station No. 40/120 Is a brownish and very compact sediment, while at Station No. 40/121 (both in the Brazilian Basin) the sediment is reddish-brown, soft and with many burrows of macrofaunal organisms. The sediment at Station No. 40/122 (Cape Verde Basin) is pale, and very consistent, with a high component of Globigerina tests. The preliminary observations of changes in sediment type along this transect, associated with likely differences in productivity and nutrient supply to the benthos, suggest that there will be detectable differences in the meiofauna. This would present similar results to those previously observed in the North Atlantic. Preliminary observations of the fauna (mainly nematodes and copepods) suggest that the greatest difference will be observed at the species level as some typical deep-sea genera have been observed. This is consistent with the concept of the deep-sea as a high diversity environment. 4.2.4 Macrobenthos (Harald Bohlmann, Dieter Gerdes/AWI, Peter Albert Lamont/SAMS) Objectives and methods The cruise from Punta Arenas to Bremerhaven provided the opportunity to sample deep-sea organisms across a wide range of latitudinal gradients in the Atlantic. Over the last few decades much deep-sea benthos data has been accumulated for the North Atlantic as far south as the Madeira Abyssal Plain but data for the South Atlantic is sparse. Therefore our main objective was to get as many quantitative samples as possible from the deep basins especially those of the South Atlantic by means of a multibox-corer and a newly developed rotating- corer. These samples provide the data basis for investigation of the vertical distribution of the animals in the sediment and for determining diversity trends along latitudinal gradients. The data will form part of the basis for the BIODEEP proposal. Work at sea The multibox-corer (MG) with the attached underwater-video system was deployed at 4 stations. During deployment at Stn. No. 40/119, the Revolvergreifer was damaged by ship movement in the rough sea and the gear could not be used again for the duration of the cruise. The multibox-corer, was not deployed at this station due to the bad weather conditions and rough sea. The results of both corers are summarized in Tab. 9 Tab. 9. Inventory of cores taken with the multibox-corer (MG) with the attached UW-video system and the Revolvergreifer (RG). Stn. No. water depth MG RG (M) number of cores number of cores ------ ----------- --------------- --------------- 40/118 5732 0 1 40/119 5088 - 0 40/120 5152 9 - 40/121 5374 9(*) - 40/122 5118 9(*) - ------------------------------------------------------- (*) bottom pictures via UW-video - not deployed In total, 28 single cores were obtained from 4 stations between 47°S and 230N for analysis of the macrofauna. The mean core length was 38 cm. Part of the MG cores from Stn. Nos. 40/120 and 40/121 had disturbed surfaces, because the cores were very full due to the soft sediments at these locations. All cores were treated according to the following procedure: Each core was divided vertically by syphoning off the top water and removing the top centimetre, approximately, of sediment. The remainder of the core was then divided into ten centimetre slices and the sediment placed directly into five litre tubes containing 2 litres of 4% formaldehyde cooled to 4°C. As soon as possible after immediate processing of the cores, the sediment was gently manipulated by hand to mix in the formalin. Sieving through 500 and 300 µm mesh was carried out at least 3 days after collection to allow time for preservation. After sieving, samples were stored in 4 % formaldehyde prior to sorting. It is considered that this procedure improves the condition of more vulnerable fauna such as polychaetes, which are often damaged on sieves when freshly collected. Preliminary results The main work on the samples has to carried out at home institutions. The basis for our preliminary impression given here is due to the careful sample treatment described above and first microscopic sorting of some core fractions on board ship, especially those from the Revolvergreifer core of Stn. No. 40/118. The dominant elements of the small, deep-sea macrofauna in our samples are polychaetes (sabellids, spionids, cirratulids, nephthyids, ophelids, and ampharetids plus a number of undetermined worms in tubes), bivalves, sipunculids and a few crustaceans. It appears that highest organism numbers occur at the southernmost station 40/118, followed by the northern station 40/122, whereas abundance values at the other two stations seemed to be lower. The sediment at Stn. No. 40/120 is especially fine and for all 9 MG cores obtained there is virtually no material, including organisms, remaining on the 500 µm sieve, and only a few mineral grains were retained on the 300 µm sieve. Macrofauna abundance at this station appears to be very low. Samples from Stn. No. 40/121 have burrows extending the full depth of the core. Some of these burrows are up to 6 mm in diameter and 1 sipunculid worm about 40 mm in length was recovered from the base of a core at about 25 cm depth. 5. Acknowledgement The achievements during both legs were to are large extent due to the effective and heartful cooperation between the ship's crews and the participating scientific personal. We are grateful to the Masters Pahl and Keil and theirs crews for the active support which helped us to overcome difficult situations and resulted not only in a scientific success, but as well in a cheerful experience. We are grateful as well to all those who were involved in the different levels of the preparations for cruise and built up the basis for our success. 6. Principal Investigators Daten Inst. Wissenschaftler Anzahl Einheit Typ der Messungen im DOD ------ ------------- ------ -------- ------------------------------ ------ Data Inst. Scientist Number Unit Type of Measurements in DOD ------ ------------- ------ -------- ------------------------------ ------ AWI Arntz, W. 11 stations B18 Zoobenthos no D01 Current meters 8 stat.: moorings deployed on the Greenwich Meridian, 3 stat.: AWI Fahrbach, E. 17 stations moorings recove red during no ANT III/4, 6 stat.: moorings deployed in the western Weddell Sea AWI Fahrbach, E. 5000 n miles D71 Current profiler (e.g. no ADCP) AWI Fahrbach, E. 112 stations H09 Water bottle stations no GO-Rosette 24x12l AWI Fahrbach, E. 112 stations H10 CTD-Stations yes H13 Bathythermograph drops XBT AWI Fahrbach, E. 310 stations with T/ probes, most traces yes transmitted over GTS AWI Fahrbach, E. 112 stations H21 Oxygen no H71 Surface measurements AWI Fahrbach, E. 5000 n miles underway (T, S) no Thermosalinograph, does not work in ice H22 Phosphates Samples were AWI Hoppema, M. 112 stations analysed with a Technicon no TRAACS autoanalyzer H24 Nitrates Samples were AWI Hoppema, M. 112 stations analysed with a Technicon no TRAACS autoanalyzer H25 Nitrites Samples were AWI Hoppema, M. 112 stations analysed with a Technicon no TRAACS autoanalyzer H26 Silicates Samples were AWI Hoppema, M. 112 stations analysed with a Technicon no TRAACS autoanalyzer AWI Hoppema, M. 112 stations H27 Alkalinity no AWI Hoppema, M. 112 stations H74 Carbon dioxide Prctical no pressure GF CO2, total CO2 H76 Ammonia Samples were AWI Hoppema, M. 112 stations analysed with a Technicon no TRAACS autoanalyzer H90 Other chemical AWI Mühlebach, A. 36 stations oceanographic measurements no Otganic chemistry, dissolved and particulate phytosterols AWI Smetacek, V. 31 stations B08 Phytoplankton no AWI Smetacek, V. 8 no unit B09 Zooplankton no AWI Smetacek, V. 8 no unit B11 Nekton no M01 Upper air observations DWDSWA Möller, H.J. 0 day(s) Synoptic met obs and no radiosondes M06 Routine standard DWDSWA Möller, H.J. 0 day(s) measurements Synoptic met obs no and radiosondes H73 Geochemical tracers (e.g. GUHB Roether, W. 104 stations freons) Freon-11, -12, -113, no CCL4, tritium, helium M01 Upper air observations IAPR Höffner, J. 16 no unit Potassium temperature lidar no profiles (nights) aktualisiert am: 08.07.2002 7. Beteiligte Institutionen / Participating Institutions Adresse Teilnehmer Fahrtabschnitt Address Participants Leg ---------------------------------- ---------------- -------------- Chile ----- UACH Instituto de Zoologia Universidad Austral de Chile 1 4 Valdivia UCV Esc. de Cs. del Mar 1 4 Universidad Catolica de Valparaiso Valparaiso UMAG Instituto de la Patagonia Universidad de Magallanes 3 4 Avenida Bulnes Punta Arenas Federal Republic of Germay -------------------------- AWI Alfred-Wegener-Institut für 26, 8 4, 5 Polar- und Meeresforschung ColumbusstraBe D-27568 Bremerhaven AWIP Alfred-Wegener-Institut für 1 4 Polar- und Meeresforschung Forschungsstelle Potsdam c/o Zoologisches Museum Berlin Invalidenstr. 43 D-1 0115 Berlin DWID Deutscher Wetterdienst 2, 3 4, 5 Seewetteramt Postfach 301190 D-20304 Hamburg FBZO FB/7AG Zoomorphologie 1, 2 4, 5 Carl-von-Ossietzky-Universitdt D-261 11 Oldenburg HSW Helicopter-Service 4 4 Wasserthal GmbH; K5tnerweg 43 D-22393 Hamburg IAPR Institut für Atmosphärenphysik 2, 4 4, 5 SchloBstr. 4-6 D-18221 KOhlungsborn IPO Institut für Polarökologie 1 4 Unlversität Kiel Wischofstr. 1-3, Geb. 12 D-24148 Kiel IUPB IUP - Institut für Umweltphysik 5 4 Abt. Tracer-Ozeanog raphie Universltät Bremen, FB 1 Postfach 330 440 D-28334 Bremen The Netherlands --------------- NIOZ Netherlands Institute 2 4 for Sea Research P.O. Box 59 1790 Ab den Burg Texel UK -- NHM The Natural History Museum 2 5 Department of Zoology Cromwell Road London, SW7B 5BD SAMS The Scottish Association 1 5 for Marine Science P.O. Box 3 Oban, Argyll PA34 4AD, Scotland Russia ------ ZMMU Zoological Museum 1 4 of the Moscow University Bolshaya Nikitskaya 6 Moscow, 103009 8. Fahirtteillnehmer/Cruise participants ANT XIII/4 ---------- Last Name First Name Inst Last Name First Name Inst ---------------- ------------- ---- ---------------- ------------- ---- Arntz Wolf AWI || Meyer Ralf AWI Bakker Karel NIOZ || Möller Hans-Joachim DWD Bittkau Anke AWI || Montiel Americo UMAG Böhm Joachim HSW || MOhlebach Anneke AWI BOchner JOrgen HSW || Mutschke Erika UMAG Bulsiewicz Klaus IUPB || Nowaczyk Jochen AWI Buschmann Alexander AWI || Rauschert Martin AWIP Dubischar Corinna AWI || Riewesell Christian HSW Eska Veit IAPR || Rios Carlos UMAG Fahrbach Eberhard AWI || Rohardt Gerd AWI Fraas Gerhard IUPB || Rohr Harald AWI George Kai Horst FBZO || Runge Maite IUPB Gerdes Dieter AWI || San Miguel Esteban Armada Gorny Janja AWI || de Chile Gorny Matthias AWI || Schlenker Björn IUPB Hansjosten Andreas AWI || Schneider Hans HSW Heras De las Miriam AWI || Schröder Michael AWI Höffner Josef IAPR || Sieverding Hiltrud IUPB Hopperna Mario AWI || SpIridonov Vassili ZMMU Horstmann Uta AWI || Stoll Michel NIOZ Jochum Markus AWI || Tan GiokNIo AWI Köhler Herbert DWD || Winterrath Tanja AWI Kolb Leif AWI || WisotzkI Andreas AWI Lardies Carrasco Marco Antonio UACH || Witte Hannelore AWI Linse Katrin IPÖ || Woodgate Rebecca AWI Maturnana Jenny UCV || Zimmermann Andreas AWI ANT XIII/5 ---------- Last Name First Name Institut ---------------- ------------- -------- Alpers Matthias IAPR Bohlmann Harald AN Debenham Nicola Jane NHM Dunker Erich AWI England Joachim DWD Eska Veit IAPR Ferrero Timothy John NHM Gerdes Dieter AWI Helmke Elisabeth AWI Höffner Josef IAPR Klauke Ulla AWI Knuth Edmund DWD Kbhler Herbert DWD Lamont Peter Albert SAMS Martinez-Arbizu Pedro FBZO MenBen Klaus AWI Schröder Sabine AWI Silvelra Moura Gisela FBZO Strohscher Birgit AWI Zahn von Ulf IAPR 8. Schiffspersonall/Ship's Crew ANT XIII/4 ANT XIII/5 ---------- ---------- Kapitän Pahl Keil 1. nautischer Offizier Keil Rodewald Leitender techn. Offizier Schulz Schulz 2. nautischer Offizier Block Block 2. nautischer Offizier Schwarze Schwarze 2. nautischer Offizier Spielke Arzt Schuster Schuster Funfoffizier Koch Hecht 2. technischer Offizier Delff Delff 2. technischer Offizier Folta Folta 2. technischer Offizier Simon Simon Elektroniker Dimmler Elektroniker Fröb Fröb Elektroniker Holtz Holtz Elektroniker Pabst Pabst Elektroniker Piskorzynski Schiffbetriebsmeister Loidl Loidl Zimmermann Neisner Neisner Facharbeiter/Deck Bdcker Bdcker Facharbeiter/Deck Bohne Facharbeiter/Deck Burzan Facharbeiter/Deck Hagemann Facharbeiter/Deck Hartwig Hartwig Facharbeiter/Deck Kreis Facharbeiter/Deck Moser Moser Facharbeiter/Deck Schmidt Schmidt Storekeeper Renner Renner Facharbeiter/Maschine Dinse Dinse Facharbeiter/Maschine Fritz Fritz Facharbeiter/Maschine Hartmann Arias Iglesias Facharbeiter/Maschine Krösche Krösche Facharbeiter/Maschine Schade Schade Koch Silinski Silinski Kochsmaat HOnecke Kochsmaat Tupy Tupy 1. Stewardess Dinse Dinse Stewardess/Krankenschwester Lehmbecker Lehmbecker 2. Stewardess Klemet Klemet 2. Stewardess Schmidt Schmidt 2. Stewardess Silinski Silinski 2. Steward Tu Huang. 2. Steward Wu Mui Wäscher Yu Yu 9. Appendix 1, Stationsliste/Station list ANT XIII/4 (see .sum file) 10. Appendix 2, XBT Data ANT XIII/4 No. Date Time Latitude Longitude Depth (GMT) (m) --- ---------- ----- ------- ------- ---- 001 18.03.1996 17.54 37°52'S 21°23'E 5074 002 20.03 38°12'S 21°41'E 5205 004 22.06 38°33'S 21°59'E 5119 005 23.55 38°50'S 22°15'E 4988 006 f 19.03.1996 02.09 39°12'S 22°34'E 5165 007 02.18 39°13'S 22°36'E 5156 008 03.59 39°27'S 22°49'E 5128 009 f 05.59 39°44'S 23°03'E 5126 010 06.09 39°44'S 23°03'E 5139 011 08.02 39°54'S 23°15'E 5041 012 11.19 40°10'S 23°27'E 4791 013 13.44 40°24'S 23°39'E 4460 014 17.58 40°34'S 23°48'E 4348 015 20.00 40°55'S 24°08'E 4327 016 21.59 41°15'S 24°27'E 4008 017 23.58 41°37'S 24°47'E 2714 018 20.03.1996 01.59 41°59'S 25°09'E 3534 019 03.02 42°12'S 25°20'E 3765 020 04.00 42°22'S 25°30'E 4157 021 05.00 42°33'S 25°40'E 4469 022 05.55 42°43'S 25°50'E 4731 023 07.00 42°55'S 26°01'E 4981 024 08.02 43°06'S 26°13'E 4987 025 08.59 43°17'S 26°23'E 5376 026 09.56 43°28'S 26°33'E 5223 027 10.55 43°38'S 26°43'E 5400 028 11.57 43°48'S 26°53'E 5704 029 13.04 43°59'S 27°04'E 5270 030 17.00 44°02'S 27°08'E 5300 031 18.02 44°12'S 27°19'E 5404 032 18.59 44°21'S 27°28'E 5454 033 20.06 44°33'S 27°39'E 5414 034 20.59 44°41'S 27°48'E 5422 035 22.00 44°49'S 28°00'E 5385 036 f 23.03 44°59'S 28°10'E 5416 037 f 23.11 44°59'S 28°10'E 5420 038 23.14 45°00'S 28°11'E 5422 039 23.58 45°08'S 28°20'E 5180 040 21.03.1996 00.59 45°17'S 28°30'E 5829 041 02.00 45°26'S 28°40'E 5404 042 02.59 45°36'S 28°50'E 5281 043 03.59 45°44'S 29°00'E 5274 044 04.56 45°54'S 29°11'E 5354 045 06.00 46°05'S 29°23'E 4283 046 07.00 46°15'S 29°35'E 5318 047 08.00 46°24'S 29°46'E 5247 048 09.00 46°35'S 29°56'E 4991 049 09.59 46°44'S 30°07'E 5430 050 11.03 46°54'S 30°18'E 5220 051 11.58 47°03'S 30°29'E 4309 052 12.58 47°13'S 30°40'E 4135 053 14.00 47°23'S 30°51'E 4463 ---------------------------------------------------- f = probe failure with repeat No. Date Time Latitude Longitude Depth (GMT) (m) --- ---------- ----- ------- ------- ---- 054 14.56 47°31'S 31°01'E 5102 055 15.55 47°39'S 31°10'E 2769 056 16.55 47°48'S 31°20'E 3697 057 17.56 47°57'S 31°31'E 4513 058 18.56 48°07'S 31°42'E 5603 059 19.57 48°16'S 31°53'E 4579 060 20.56 48°26'S 32°03'E 2648 061 21.57 48°35'S 32°15'E 3975 062 22.58 48°45'S 32°27'E 3973 063 22.03.1996 00.01 48°55'S 32°39'E 4411 064 00.59 49°04'S 32°50'E 4066 065 f 01.59 49°14'S 33°01'E 4003 066 02.07 49°15'S 33°03'E 3966 067 02.57 49°23'S 33°12'E 4975 069 04.55 49°42'S 33°35'E 4074 069 06.03 49°54'S 33°49'E 5237 070 06.59 50°03'S 34°00'E 4733 071 07.58 50°11'S 34°12'E 4610 072 08.59 50°20'S 34°23'E 4566 073 09.58 50°30'S 34°34'E 5163 074 10.57 50°39'S 34°44'E 5235 075 12.04 50°50'S 34°58'E 5185 076 12.58 50°58'S 35°07'E 4880 077 13.53 51°07'S 35°18'E 4775 078 14.57 51°17'S 35°31'E 4901 079 15.55 51°26'S 35°42'E 5198 080 16.55 51°36'S 35°55'E 4261 081 17.57 51°46'S 36°08'E 4875 082 19.00 51°58'S 36°23'E 4596 083 20.08 52°10'S 36°39'E 4237 084 21.01 52°21'S 36°52'E 4516 085 22.01 52°32'S 37°07'E 4508 086 23.06 52°45'S 37°22'E 4492 087 23.03.1996 00.00 52°55'S 37°36'E 4459 088 00.57 53°06'S 37°50'E 4412 089 02.02 53°19'S 38°06'E 4296 090 03.00 53°30'S 38°21'E 4271 091 03.59 53°41'S 38°35'E 4185 092 04.58 53°53'S 38°50'E 3500 093 18.46 54°01'S 38°20'E 4129 094 19.55 54°01'S 38°03'E 4314 095 21.04 54°00'S 37°46'E 4622 096 24.03.1996 02.02 54°00'S 37°26'E 4710 097 02.53 54°00'S 37°10'E 4736 098 03.50 54°00'S 36°53'E 4772 099 11.09 54°00'S 36°36'E 4560 100 12.17 54°00'S 36°19'E 4844 101 13.23 54°00'S 36°02'E 4701 102 18.18 54°00'S 35°45'E 4724 103 19.32 53°59'S 35°28'E 4822 104 20.42 54°00'S 35°11'E 5034 105 21.52 54°01'S 34°54'E 4778 106 22.58 54°00'S 34°37'E 5310 107 25.03.1996 00.05 54°00'S 34°17'E 5327 ---------------------------------------------------- f = probe failure with repeat No. Date Time Latitude Longitude Depth (GMT) (m) --- ---------- ----- ------- ------- ---- 108 04.32 54°00'S 34°02'E 5432 109 05.40 54°00'S 33°42'E 5440 110 06.37 54°00'S 33°25'E 4571 111 07.40 54°00'S 33°07'E 5448 112 08.32 54°00'S 32°51'E 5433 113 09.29 54°00'S 32°34'E 5296 114 14.00 54°00'S 32°17'E 5470 115 14.57 54°00'S 32°00'E 4630 116 16.12 53°59'S 31°43'E 5483 117 17.20 53°59'S 31°25'E 5514 118 18.31 54°00'S 31°07'E 5483 119 19.29 54°00'S 30°52'E 4981 120 26.03.1996 00.06 54°00'S 30°36'E 5272 121 01.09 54°00'S 30°19'E 5510 122 02.28 54°00'S 30°01'E 5044 123 03.39 54°00'S 29°44'E 5510 124 04.51 54°00'S 29°27'E 5227 125 06.04 54°00'S 29°10'E 4603 126 13.51 54°00'S 28°54'E 5294 127 14.59 54°00'S 28°34'E 4871 128 15.53 54°00'S 28°19'E 5173 129 16.56 54°00'S 28°02'E 4053 130 18.06 54°00'S 27°45'E 5297 131 27.03.1996 01.49 54°02'S 27°21'E 4185 132 02.58 54°01'S 27°03'E 4544 133 04.46 54°00'S 26°46'E 4896 134 14.02 54°00'S 26°29'E 4779 135 15.05 54°00'S 26°13'E 3302 136 16.04 54°00'S 25°55'E 3318 137 23.54 54°00'S 25°35'E 4179 138 28.03.1996 00.42 54°00'S 25°22'E 4147 139 01.43 53°58'S 25°04'E 4534 140 02.41 53°52'S 24°51'E 4844 141 06.15 53°46'S 24°37'E 3294 142 07.21 53°58'S 24°38'E 4132 143 08.13 54°08'S 24°38'E 4935 144 09.13 54°19'S 24°37'E 4518 145 10.08 54°29'S 24°37'E 4186 146 11.16 54°41'S 24°36'E 4449 147 16.38 54°54'S 24°22'E 3823 148 17.38 55°01'S 24°11'E 4141 149 18.36 55°08'S 23°59'E 3870 150 19.36 55°16'S 23°48'E 3961 151 20.33 55°23'S 23°37'E 4685 152 29.03.1996 01.05 55°32'S 23°26'E 4668 153 02.07 55°38'S 23°12'E 4657 154 03.02 55°46'S 23°02'E 5115 155 04.05 55°54'S 22°49'E 5237 156 05.02 56°02'S 22°37'E 5113 157 06.05 56°10'S 22°23'E 5088 158 13.57 56°14'S 22°09'E 5222 159 15.03 56°26'S 21°57'E 4805 160 16.01 56°34'S 21°44'E 5116 161 17.19 56°45'S 21°25'E 5023 No. Date Time Latitude Longitude Depth (GMT) (m) --- ---------- ----- ------- ------- ---- 162 18.09 56°52'S 21°13'E 5009 163 22.22 57°00'S 21°01'E 4738 164 23.20 57°01'S 20°46'E 5213 165 30.03.1996 10.34 57°11'S 19°06'E 4824 166 11.53 57°12'S 18°46'E 4878 167 12.51 57°14'S 18°32'E 4994 168 13.49 57°16'S 18°19'E 4941 169 14.52 57°17'S 18°04'E 5318 170 16.23 57°19'S 17°44'E 3850 171 17.57 57°21'S 17°23'E 5396 172 31.03.1996 00.14 57°23'S 17°12'E 4803 173 02.01 57°25'S 16°48'E 5327 174 03.34 57°27'S 16°26'E 5116 175 04.59 57°29'S 16°06'E 5351 176 06.33 57°30'S 15°46'E 5232 177 07.59 57°32'S 15°29'E 4965 178 12.20 57°32'S 15°29'E 5345 179 13.46 57°35'S 14°52'E 5655 180 14.56 57°37'S 14°34'E 4955 181 16.30 57°39'S 14°11'E 5607 182 18.00 57°41'S 13°49'E 5711 183 23.34 57°43'S 13°28'E 5513 184 01.04.1996 01.04 57°45'S 13°07'E 5655 185 02.27 57°47'S 12°48'E 5550 186 04.01 57°49'S 12°24'E 5506 187 05.38 57°51'S 12°02'E 5175 188 07.08 57°52'S 11°44'E 5609 189 15.55 57°54'S 11°22'E 5999 190 17.30 57°36'S 11°02'E 5379 191 19.01 57°58'S 10°46'E 5375 192 20.35 58°00'S 10°29'E 5570 193 22.11 58°01'S 10°12'E 5621 194 23.30 58°02'S 09°57'E 5589 195 02.04.1996 05.07 58°05'S 09°36'E 5501 196 06.24 58°06'S 09°18'E 5284 197 07.40 58°08'S 08°56'E 4947 198 08.45 58°10'S 08°38'E 4908 199 09.42 58°11'S 08°21'E 4440 200 10.42 58°13'S 08°04'E 3248 201 17.17 58°16'S 07°42'E 3998 202 18.29 58°17'S 07°20'E 4009 203 19.25 58°19'S 07°03'E 5004 204 20.31 58°20'S 06°45'E 5067 205 21.56 58°22'S 06°26'E 5342 206 23.10 58°24'S 06°06'E 5143 207 03.04.1996 07.12 58°27'S 05°44'E 5172 208 08.07 58°28'S 05°27'E 5040 209 09.04 58°29'S 05°10'E 5331 210 10.00 58°31'S 04°52'E 5209 211 11.02 58°33'S 04°32'E 5445 212 12.13 58°35'S 04°10'E 5514 213 17.05 58°37'S 03°48'E 5083 214 18.14 58°39'S 03°22'E 5611 215 18.58 58°41'S 03°06'E 4722 No. Date Time Latitude Longitude Depth (GMT) (m) --- ---------- ----- ------- ------- ---- 216 19.55 58°43'S 02°45'E 4925 217 20.58 58°45'S 02°21'E 4983 218 21.55 58°47'S 02°01'E 4186 219 04.04.1996 02.38 58°48'S 01°43'E 4644 220 03.50 58°50'S 01°22'E 4734 221 04.50 58°53'S 01°02'E 5326 222 05.47 58°55'S 00°43'E 4028 223 06.47 58°57'S 00°22'E 3912 224 07.36 59°00'S 00°04'E 4459 225 05.04.1996 16.50 59°24'S 03°11'W 4765 226 18.00 59°13'S 03°11'W 4897 227 19.05 59°02'S 03°12'W 4994 228 20.18 58°52'S 03°12'W 5371 229 21.24 58°42'S 03°10'W 4017 230 22.28 58°32'S 03°09'W 4535 231 23.37 58°22'S 03°11'W 4978 232 06.04.1996 00.49 58°12'S 03°13'W 3723 233 01.00 58°10'S 03°13'W 4187 234 01.44 58°03'S 03°13'W 4656 235 02.52 57°53'S 03°13'W 3688 236 04.05 57°43'S 03°13'W 3653 237 05.04 57°33'S 03°14'W 3984 238 06.07 57°23'S 03°14'W 3788 239 07.12 57°13'S 03°14'W 3895 240 08.17 57°03'S 03°14'W 4022 241 09.26 56°53'S 03°14'W 3461 242 10.36 56°43'S 03°14'W 3325 243 13.20 56°33'S 03°14'W 3731 244 14.21 56°23'S 03°15'W 3774 245 15.26 56°13'S 03°15'W 2834 246 16.28 56°03'S 03°16'W 3616 247 17.32 55°53'S 03°16'W 2812 248 18.36 55°43'S 03°16'W 4623 249 19.35 55°33'S 03°16'W 1834 250 20.42 55°23'S 03°16'W 3011 251 21.49 55°13'S 03°17'W 3154 252 22.58 55°03'S 03°17'W 3219 253 07.04.1996 00.06 54°53'S 03°17'W 2699 254 01.17 54°44'S 03°17'W 2542 255 02.22 54°35'S 03°17'W 2698 256 03.37 54°25'S 03°18'W 1812 257 13.55 54°19'S 03°13'W 2520 258 15.00 54°11'S 02°55'W 2302 259 16.01 54°03'S 02°38'W 2592 260 17.05 53°56'S 02°21'W 2157 261 18.03 53°49'S 02°04'W 2405 262 19.01 53°42'S 01°48'W 2457 263 20.03 53°34'S 01°31'W 2416 264 21.04 53°27'S 01°14'W 2318 265 22.02 53°20'S 01°00'W 2378 266 23.02 53°13'S 00°43'W 2505 267 08.04.1996 00.02 53°06'S 00°28'W 2554 268 01.03 52°59'S 00°11'W 2493 269 02.04 52°52'S 00°05'E 2684 No. Date Time Latitude Longitude Depth (GMT) (m) --- ---------- ----- ------- ------- ---- 270 03.03 52°44'S 00°22'E 2825 271 04.04 52°37'S 00°38'E 2725 272 05.02 52°30'S 00°53'E 2836 273 05.59 52°23'S 01°08'E 2635 274 06.57 52°16'S 01°24'E 2706 275 08.00 52°09'S 01°40'E 2766 276 09.00 52°02'S 01°56'E 2658 277 10.07 51°55'S 02°13'E 2817 278 11.04 51°47'S 02°29'E 3122 279 11.58 51°40'S 02°42'E 2843 280 12.58 51°34'S 02°57'E 2947 281 14.04 51°28'S 03°09'E 3490 282 15.01 51°23'S 03°21'E 3323 283 16.04 51°17'S 03°34'E 3318 284 17.05 51°11'S 03°46'E 3285 285 18.04 51°06'S 03°58'E 3585 286 19.02 51°00'S 04°09'E 3612 287 20.10 50°55'S 04°21'E 3474 288 21.10 50°49'S 04°34'E 2890 289 22.23 50°43'S 04°45'E 3536 290 23.45 50°36'S 05°02'E 3389 291 09.04.1996 01.11 50°29'S 05°15'E 1208 292 02.13 50°25'S 05°24'E 2691 293 03.20 50°21'S 05°33'E 3639 294 04.50 50°15'S 05°45'E 3425 295 11.04.1996 11.54 52°15'S 03°25'E 3177 296 13.37 52°30'S 03°05'E 1437 297 14.52 52°40'S 02°53'E 2736 298 16.04 52°50'S 02°42'E 2602 299 17.26 53°00'S 02°29'E 2638 300 18.35 53°10'S 02°17'E 2718 301 19.50 53°20'S 02°05'E 2659 302 20.54 53°30'S 01°54'E 2595 303 22.27 53°40'S 01°40'E 2718 DATA PROCESSING NOTES Date Contact Data Type Data Status Summary 04/15/97 Diggs CTD Submitted successfully retrieved files from ftp site 04/15/97 Witte SUM/DOC Submitted CTD tar files available on their ftp site ftp.awi-bremerhaven.de (login: anonymous) 04/28/97 Fahrbach CTD/BTL Data are NonPublic please password control 02/01/99 Witte BTL Submitted File available on ftp site 02/02/99 Witte SUM/DOC Update Requested by sd could you please re-submit the SUM file? It would seem as though the time parameters are always at 3,4 or 5 minutes past the hour. This could not possibly be correct. Also, do you have a more comprehensive documentation file than the one you provided? 02/04/99 Witte SUM/DOC Data Update will update sum asap & ask colleague for doc 02/12/99 Anderson SUM Reformatted by WHPO 02/12/99 Witte CTD/BTL Status Update protect by a password until the 31th of December 1999 02/12/99 Witte SUM Data Update I prepared a new SUM file and put it on your ftp server in the directory INCOMING. The name is ANTXIII_4.SUM. 02/12/99 Diggs SUM Data Merged/OnLine updated with the WOCE formatted sumfile 06/07/99 Klein CFCs/He/Neon Submitted for DQE Tritium not yet ready to submit 02/29/00 Anderson SUM Data Update I have reformatted and "corrected" the station/cast problem for s04a, but that isn't the only difference in the two .sum files (sr04e and s04a, 06AQUANTXIII_4). Times and positions are different in the two files for the same station and cast in some cases. Also station 14 cast 3 does not appear in s04a (this may not be the only case) and s04a has what I think is the CTD # under COMMENTS, but sr04e does not. 03/01/00 Diggs BTL Data Update Changes: … Changed 06AQANTXIII/4 to 06AQANTXIII_4 … Moved STNNBR to align with the station numbers (right justification) … Added "QUALT1" header over the quality 1 flag fields _ … Added date/time stamp All tables and related HTML files have been updated accordingly. 03/01/00 Diggs SUM Data Update I found the original, updated SUM file sent by Hannelore Witte 2/12/1999. It was not in WOCE format, and Sarilee received it and reformatted it on the same day. Witte sent a file that was different from the original in that the STN# is a combination of the Station# and Cast#. In any case, Sarilee apparently split these out into their original components, making the new sumfile match the bottle data files for SR04 (there wasn't ever one for S04A, even though they're the *same line*). I have reformatted this sumfile (again) to change the WOCE section number to be S04 instead of SR04, for consistency's sake. I am now combining the two lines into one, even though they will have separate representation on the Southern Onetime and Repeat tables. However, the onetime designation of the cruise will take precedence as is our custom here at the WHPO. The repeat listing will simply link to the onetime section. 03/15/00 Newton CFCs/He/Neon Data Merged/OnLine Notes on merging CFCs HELIUM NEON in: 06AQANTXIII_4 S04 BTLNBR in 06aqantxiii_4 _data.199906.hyd.txt is really SAMPNO. Following sta/cast were in new cfcHeNe file, but not in existing .hyd file or .sum file: 2/1 104/2 105/1 106/1 107/1 108/1 109/1 110/1 111/1 114/1 but 2/1 109/1 110/1 111/1 114/1 contained entirely missing data values. pressure sequenced file and changed DELHE3 missing from -9 to -999. 15 Mar 2000 05/19/00 Fahrbach CTD/BTL Data are Public Possible errors: I received several messages on different sections and did notice only afterwards that this was not a repeat, but referring to a different section. I think I had authorized you earlier to use our WOCE data openly and repeated now. I might be that my earlier statement referred only to some sections. This is now for all. However, I have a problem and would like your opinion. We only recently noticed that there was a problem with our FSI-CTD which did not show up in the lab calibrations. Therefore we had to reprocess all our data observed since 1995. This is now finally finished. The changes are less than a few mK and mPSU. I can not resubmit the corrected data before 1 June because my technician is seriously ill. What is your opinion: 1. Could you check if the data was resubmitted recently? 2. If not, should we resubmit at all when he will return? 3. Do you want to include in the CD-ROM the present data? 11/01/00 Bartolacci CTD/BTL Website Updated; Data are public As per Farhbach's clarification on 19/5/00 the bottle and ctd files for this cruise have been unencrypted and made public. All references have been updated to reflect this change. 05/07/01 Witte CTD/BTL Update Needed the data of our cruise ANTXIII/4 I sent to WOCE in 1997 are wrong. There are some errors in the data of EXPOCODE 06AQANTXIII/4 WHP_ID SR4 CRUISE DATE 031796 TO 052096 1. BOTTLE data: We got some questions about our nutrients data and when we compare the data of us with the data I sent to WOCE we see that the WOCE data are too small. When I checked them I found that the data must changed three times from µmol/l to µmol/kg. The CTD-data in the bottle file had the same error than the CTD- data. 2. CTD-data: The CTD-data are processed with the PT1 temperature sensor which had had a hardware error. The new CTD data are processed with the PT2 temperature sensor. Please let me know what I shall do with the new cruise data and who must know about this mistake. 06/21/01 Uribe BTL Website Updated; CSV File Added Bottle exchange file was put online. 06/27/01 Uribe CTD Website Updated; CSV File Added CTD exchange files have been put online. 12/04/01 Diggs CTD/BTL/SUM Submitted Data need to be merged, see note: new data submission from Hannalore Witte 06/18/2001 data need to be re-merged with existing online files. original/20010618.052257_WITTE_S04-SR04 12/26/01 Uribe CTD Website Updated; CSV File Added CTD has been converted to exchange using the new code and put online. 01/03/02 Hajrasuliha CTD Internal DQE completed created *check file for this cruise. 06/26/02 Coartney DOC Website Updated New text doc online. 10/20/02 Kappa DOC Website Updated Added complete text and pdf files of final cruise report, published by the Alfred Wegener Institute for Polar and Marine Research: D-27515 Bremerhaven - FRG. The tracer report that was previously online (submitted by Birgit Klein) is included in this final cruise report. The pdf version includes figures and links between the figures and tables and the relevant text passages.