1. CRUISE NARRATIVE: SR04 (Updated MAY 2005) 1.1. HIGHLIGHTS CRUISE SUMMARY INFORMATION WOCE section designation SR04 Expedition designation (ExpoCode) 06AQANTXV_4 Chief Scientist/affiliation Eberhard Fahrbach / AWI Dates 28 MAR 1998 - 23 MAY 1998 Ship R/V POLARSTERN Ports of call Punta Arenas Cape Town 39°23.5'S Station geographic boundaries 57° 35'W 11°49.6'E 70°29.3'S Stations 151 CTD-Stations Floats and drifters deployed 0 Moorings deployed or recovered Greenwich Meridian: 6 deployed, 7 recovered Western Weddell Sea: 10 deployed, 5 recovered CHIEF SCIENTIST CONTACT INFORMATION: DR. EBERHARD FAHRBACH Alfred-Wegener Inst. fur Polar und Meeresforschung Postfach 1201061 Columbusstrasse • Bremerhaven, D-27515 • GERMANY TEL: 49-471-4831-501 • FAX: 49-471-4831-149 or -425 EMAIL: efahrbach@awi-bremerhaven.de CONTRIBUTING AUTHORS Richard Bellerby Rüdiger Hartig Katrin Meissner Klaus Bulsiewicz Mario Hoppema Matthias Monsees Carlos Mir Casanovas Oliver Huhn Adriene Pereira Eberhard Fahrbach Olaf Klatt Christian Rodehacke Antonio Härter Fetter Herbert Köhler Gerd Rohardt Gerhard Fraas Jens Langreder Norbert Schlüter Martin Frenzel Alexeij laremtchouk Michael Schröder Sabine Harms Sven Loske Andreas Wisotzki Hannelore Witte 1.2. SUMMARY AND ITINERARY Cruise Track See Figure 1a (WHPO Station Location Map) and Figure 1b (AWI Cruise Track) Number of Stations 151 CTD-Stations were occupied. See section 1.3 for a complete breakdown of stations and the work done at each. Sampling Water samples measurements included salinity and oxygen, as well as the following tracers: CFCs (Freon-11 and Freon-12, Freon-113, CCL4), tritium, 3He and He. Nutrients (SILCAT, NITRAT, NITRIT, PHSPHT), Total Carbon, partial pressure Of CO2 and NEON were also collected Moorings To obtain time series, 12 moorings were recovered and 16 were deployed (Appendix 1). 10 of the deployed moorings were conventional ones and 6 were expendable. Regionally these operations focused on four components: 1. To measure the outflow from the northwestern Weddell Sea into the Weddell-Scotia Confluence, a hydrographic section, consisting of 28 stations, extended from Joinville Island to the southeast (Fig. 7a and 8). This section is termed Joinville section. It represents the fifth repeat since 1989. 5 moorings were recovered and 3 were deployed along this section (Fig. 7b and 17; Appendix 1, Tab. 1 and 2). 2. To determine the water mass properties in the Weddell- Scotia Confluence, two quasi-meridional hydrographic sections with 39 stations were carried out, one east of the South Orkneys and the other one west of the islands (Fig. 7a, 9, 10). These sections are called South-Orkney-east and South-Orkney-west sections. A section with 7 CTD-stations was carried out across the northern boundary of the Powell Basin, extending west-east along the South Scotia Ridge towards the Scotia Sea (Fig. 7a and 11). This section is called Powell-Basin-boundary section. 6 expendable and 1 conventional mooring were deployed along this section (Fig. 7b and 18; Appendix 1, Tab. 2). 3. To measure the exchanges between the eastern and the western Weddell Sea, a hydrographic section with 38 stations was carried out along the Greenwich Meridian. This section extended northward from the ice shelf front at 69°38.5'S to 55°S (Fig. 7a and 12), and was previously measured in 1992 and 1996. Along this section 7 moorings were recovered and 6 deployed (Fig. 7b and 19, Appendix 1, Tab. 3 and 4). 4. To determine the structure and transport of the Antarctic Circumpolar Current, a hydrographic section was carried out along the Greenwich Meridian from the northern boundary of the Weddell Gyre (55°S) to the Subtropical Front (48°S; Fig. 7a and 12). At 48°S the section turns to the northeast and ends at 39°25'S, 11°48'E. For simplicity the complete section will be called Greenwich-Meridian section, despite its deviation from that longitude. To resolve the frontal system, XBTs were launched between CTD stations at approximately 10 nm distance from 57°S on northward. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 INVESTIGATIONS OF ACOUSTIC LOCATION OF MOORINGS Alexeij laremtchouk (AAI) Objectives Acoustic methods are used to locate and release moorings. However, only rarely signals from the deployed instruments can be received by the ship, whereas the releases receive the transmitted signals and operate properly. The extent, to which the ship's noise or natural perturbations affect the sound propagation, were investigated. Work at sea The tests indicated that all used positioning systems exhibit similar behaviour, mainly determined by the parameters of the sounding signals. The vessel noise was found to have the most significant impact on performance of the acoustic instruments. During the cruise special measurements of the arriving beacon signal and of the vessel noise in the close-field zone were conducted. The collected data made it possible to evaluate the actual signal-to-noise ratio and operating range of the transponder systems. See the final report for details. Preliminary results 1. The impact of currents on operation of ranging systems is negligible: practically, currents do not deflect rays neither cause extra attenuation of the signal; the Doppler shift of frequency is also very small. 2. Stratification of water has no influence on deep transponders, but may cause a significant extra attenuation of a signal coming to the vessel from a beacon floating underneath the ice at a depth of 50 to 100 m. Extra attenuation occurs when a beacon happens to be inside of an acoustic channel, i.e. in layers with small sound velocity. Actual attenuation may be estimated with the aid of computer programs (see the final report). 3. The vessel noise is the main factor limiting the operating range of a transponder system. Its level at the depth of 10 to 20 m amounts to about 0.1 to 0.3 Pa/ (sq. root)Hz when "Polarstern" is at rest, and probably about 25 dB more when she moves. The noise is produced by turbulent eddies and air bubbles clouding around the body of the vessel, the decrease in level is only expected at distances large enough in comparison with 100 m (no accurate estimate is available). The working range of the transponder systems with the short transducer cable is expected to be about 300 m. When the system is operated from an ice floe far from the vessel, the range is expected to increase up to 5-8 km (depending on frequency). 4. On average the ambient noise does not exceed the level of -55 dB relative to Pa/ (sq. root)Hz and is small in comparison with the vessel noise. See the description of computer programs for prediction of the ambient noise level in the final report. 5. Because of possible multi-path arrivals of the beacon signal, the vessel transducer should not be placed closer than 8 m to the water surface or the body of the ship (MORS and EG&G systems). The Benthos system with its long (two seconds) messages must always suffer from multi-paths arrivals which can additionally reduce the operating range. Recommendations 1. In order to protect the deck receiving transponder from the vessel noise, one may try to construct a baffle. The transducer size is about the wavelength, and this implies that the far field zone starts approximately at distances of 20 to 50 cm from the transducer. A baffle in the far field zone appears to be unacceptably large (about 1 m in radius), even for a deep transducer. Constructing a close field baffle is very complicated and must be controlled by measurements. Also, an effective baffle will make the hydrophone looking strictly downwards. Therefore, the use of a baffle is not feasible. 2. The most promising, realistic, and cost effective way to improve the situation is to change the shape and duration of the signal transmitted by the beacon. Increasing duration of the signal to 1-4 s will result in an increase of the signal-to-noise ratio by 20-25 dB, and consequently the operating range will reach at least 36 km. The frequency of the signal should not be kept constant but should be linearly increased with time. Then, scanning through the range of 1 kHz formally results in ranging accuracy of 1.5 m which is enough for mooring search. The working frequency band should be set to 8-12 kHz (a tradeoff between sound absorption and the vessel noise). With the spatial step of 1.5 m, about 8000 bins are needed to cover the range of 12 km; therefore, there will be no problems with digital processing. 3. For ranging purposes it seems advantageous to periodically send signals from the beacon without synchronizing clocks with the deck unit. This results in an extra measurement, but also makes it possible to achieve the maximum allowed accuracy. Improper clock synchronization may explain the discrepancy of 55 m of the MORS ranging system against geometrical evaluation of distance. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 1.3. PRINCIPAL INVESTIGATORS AND PROGRAMS Inst. | Scientist | No. | Unit | Type of Measurements | Comments -------|-------------|------|----------|--------------------------|-------------------------------------------------- AWI | Fahrbach, E | 28 | stations | Current meters | 6 moorings deployed on the Greenwich Meridian | | | | | 7 moorings recovered on the Greenwich Meridian | | | | | 10 moorings deployed in the western Weddell Sea | | | | | 5 moorings recovered in the western Weddell Sea AWI | Fahrbach, E | 5000 | n miles | Current profiler | VM-ADCP-profiles AWI | Fahrbach, E | 136 | stations | Water bottle stations | GO rosette 21x12l bottles AWI | Fahrbach, E | 151 | stations | CTD-Stations | AWI | Fahrbach, E | 196 | drops | Bathythermograph drops | AWI | Fahrbach, E | 136 | stations | Oxygen | GO rosette 21x12l bottles AWI | Fahrbach, E | 136 | stations | Phosphates, NO2, NO3, | Samples were analyzed by NIOZ an board with | | | | Silicates, Ammonia | Technicon TRAACS Autoanalyser system AWI | Fahrbach, E | 5000 | n miles | Surface measurements | Thermosalinograph | | | | | underway (T, S) DWDSWA | Hartig, | 55 | day (s) | Upper air observations | Synoptic met obs and radiosondes DWDSWA | Hartig, | 55 | day (s) | Routine standard | Synoptic met obs and radiosondes | | | | measurements | GEOMAR | Heeschen, | 119 | stations | Other dissolved gases | Methane GEOUNB | Roether, W. | 106 | stations | Geochemical tracers | Freon-11, -12, -113, ccl4, tritium, helium IUHB | Hoppema, M | 136 | stations | Alkalinity, CO2 | Partial pressure of CO2, total CO2 UFT | Heuchert, | 38 | stations | Dissolved organic matter | Water samples to sample bacteria UFT | Heuchert, | 16 | stations | Pelagic bacteria/ | Water samples to sample bacteria | | | | microorganisms | UFT | Heuchert, | 38 | stations | Particulate organic | Water samples to sample bacteria | | | | matter (e.g. POC, PON) | ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 1.4. SCIENTIFIC PROGRAMMES AND METHODS The "Polarstern" cruise ANT XV/4 started on 28 March 1998 in Punta Arenas and lead to the Weddell Sea (Fig.1). The major scientific aim of the cruise was to investigate the role of the Weddell Sea in the global climate system. The cruise consisted of two parts - the first took place in the western Weddell Sea and the Weddell-Scotia Confluence, the second concentrated on the Southern Ocean between the coast of Antarctica and the Subtropical Front off South Africa, mostly along the Greenwich Meridian. A major part of the deep and bottom waters of the global ocean are ventilated by water mass formation in the Weddell Sea. Its intensity controls the global thermohaline circulation and consequently the effect of the ocean on large scale climate variations. Water mass formation in the Weddell Sea is driven by cooling in winter and consequent sea ice formation, as well as by the interaction between the ocean and the ice shelves. On the shelf, water masses dense enough to sink to the bottom of the Weddell Basin can be generated. 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. The outflow in the western Weddell Sea consists of near surface, intermediate, and deep components. The near surface water is, to a large extent, shelf water from the Weddell Sea which, in the area of the Weddell-Scotia Confluence, encounters water from the Antarctic Circumpolar Current. The confluence gives rise to a system of two fronts, the Weddell and the Scotia Front. These fronts enclose a water mass whose properties result from the mixing of the converging water masses and the local atmosphere-ice-ocean interaction. If this water crosses the South Scotia Ridge at intermediate depth and sinks along the front, it may contribute to the ventilation of the deep global ocean without ever having been bottom water in the Weddell Sea, the traditionally assumed ventilation area. The deep components of the Weddell Sea water flow along the South Scotia Ridge to the east and pass through gaps to the north to fill the deep basins of the Atlantic and Indian Oceans. At the Greenwich Meridian water masses modified in the eastern Weddell Sea by injection of circumpolar water masses flow westward in the southern part of the gyre. At the gyre's northern rim modified deep water and newly formed bottom water recirculate to the east. During the past years the Warm Deep Water, injected from the Antarctic Circumpolar Current, became warmer and saltier. The bottom water in the Weddell Basin increased its temperature by approximately 0.01 K per year since 1989. The present data set indicates significant regional differences of these variations. In the Western Weddell Sea the warming of the Warm Deep Water and Weddell Sea Bottom Water continued- in the interior of the gyre cooling occurred. The transition from the Antarctic Circumpolar Current to the Weddell Gyre is shifted south from 1996 to 1998, which might indicate a new warming event for the interior. The regional displacement of these variations may indicate if and how local atmosphere-ice- ocean interaction and the inflow of water masses from the north affect the bottom water formation. Of particular interest are variations affecting the stability of the water column and the atmosphere-ice-ocean interaction west of Maud Rise. In this area a large open ocean polynya was observed in the seventies, leading to open ocean formation of deep water. The transition of water mass formation processes occurring on the continental slope to those in the open ocean can cause abrupt changes and may affect the global thermohaline circulation. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 Objectives: The operations concentrated on four regional components: The outflow from the southern Weddell Sea into the Weddell- Scotia Confluence, the exchange between the Weddell Sea and the Antarctic Circumpolar Current within the Weddell-Scotia Confluence, the exchange of water masses between the eastern and the western Weddell Sea across the Greenwich Meridian, and the structure of the Antarctic Circumpolar Current at the Greenwich Meridian. For this purpose, the water mass properties and currents were measured with a CTD-probe (Conductivity/Temperature/Depth) combined with a rosette water sampler and an ADCP (Acoustic Doppler Current Profiler) along hydrographic sections. From the water samples measurements of the following tracers were carried out: CFCs (Freon-11 and Freon-12, Freon-1 13, CCL4), tritium, 3He and He. CFCs were measured on board by gas chromatography. The other tracers were collected for subsequent analyses on shore. Salinity was measured from the water bottles to calibrate the CTD and to control the water samplers. Current meter moorings were recovered and redeployed along the Greenwich Meridian and in the western Weddell Sea off Joinville Island, and deployed along the South Scotia Ridge west of the South Orkney Islands. The physical oceanography programme onboard is part of the international DOVETAIL project (Deep Ocean VEntilation Through Antarctic Intermediate Layers), a contribution to the SCOR affiliated iAnzone programme (Scientific Committee on Oceanic Research). In this context the instruments at the moorings in the western Weddell Sea were provided by the Universitat Politecnica de Catalunya in Barcelona, Spain. A project of sea ice investigations with remote sensing techniques aimed to develop a new algorithm for cloud masking with infrared images. For this purpose in-situ data, e.g. observations of clouds and surface conditions, weather charts and radiosonde measurements, were collected to validate the analyses. Measurements of the CO2 system and nutrients were performed to investigate the processes which determine the potential of the Weddell Sea to take up atmospheric CO2. For this purpose the total inorganic carbon content, TCO2, and the partial pressure Of CO2 (pCO2) were measured. A geochemistry programme aimed to investigate the potential of methane as a water mass tracer. Its concentration is influenced by the atmospheric content, as well as by production and consumption within the ocean. The 12C/13C ratio of the dissolved CH4 provides an indication on the methane decrease in the water column due to oxidation, since this process preferentially consumes the lighter isotope. The comparison with the distribution of other tracers is used to develop a model for the methane circulation in higher latitudes. The microbiology programme aimed to estimate the contribution of the microbial community to the biological activity within the sea ice and the water column during autumn, and its role in the carbon cycle. For this purpose samples were collected to measure bacterial elemental diversity with X-ray microanalysis (XRMA), and to determine dissolved organic carbon (DOC) production and degradation in reference to the algal standing stock. The colonization of sinking particles was investigated with water samples from which pure strains of attached heterotrophic bacteria were isolated. The bacterial cells of the water column as well as the bacteria attached to particles will be counted after return. Laboratory experiments on silicon uptake and release of sponges and sponge needle mats took place in the framework of the benthos programme to establish a benthic silicon budget. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 Itinerary: The fieldwork began with XBT-deployments across Drake Passage. On 1 April we reached the operation area in the northwestern Weddell Sea. Following the recovery of a mooring we starlet a CTD-section. In the evening a search and rescue message for three missing members of the Argentinean Station "Orcadas" was received. They had not returned from a trip around the island by boat. At that time we were too far away to reach the South Orkneys in time and participate in the search. On 11 April a new message was received, saying that the boat was found on the shore. At this time we were near the island and our helicopter participated in the ongoing search of the missing persons. The helicopter could operate from the Argentinean icebreaker "Almirante Irizar", permitting us to continue the research. Bad weather obliged us to finish the search without any positive result. The work in the western Weddell Sea and the Weddell-Scotia Confluence, was finished on 22 April. The ice conditions were appropriate, to the autumn situation. Multi-year ice floes, surrounded by newly formed ice, were advected northward from the southern Weddell Sea. However, the predominant southwesterly winds and the currents of the Weddell Gyre generated enough leads in the ice field, that no pressure was built up and work could proceed without serious restrictions. During the passage to the Neumayer Station the wind increased to 10 Bft. The waves flushing on the deck damaged the door of the nutrient laboratory container. In spite of serious damages the container could be repaired and the nutrient measurements could be continued. Southerly winds advected cold air from the continent and new ice formed quickly. On 26 April we crossed the ice edge at 66°1O'S, 21°00'W, further north than expected. However, strong winds kept the ice field open and we could reach the coast without problems. On 28 April we reached Atka Bay. The bay was covered with a sheet of young ice broken by leads. Strong winds and bad visibility prohibited the supply operations in the morning. By the afternoon winds had calmed down sufficiently to permit helicopter flights. The station's physician from the last overwintering crew came on board after a prolonged stay at the station, and spare parts and food supplies were dispatched. The in-between fair weather permitted helicopter flights, so that the cruise participants could visit the station and the overwintering crew could come on board. Research continued at the Greenwich Meridian on 29 April. The first station of the meridional transect was carried out in a polynya next to the ice shelf front. The ice consisted of small floes of young ice and heavily grinded multi-year floes. The floe sizes were too small to deploy the two sea ice buoys which we had on board. The northern ice edge at 69°15'S was reached on 30 April. Despite of strong winds, the CTD and mooring work along the meridional transect occurred without significant delay. Seven moorings were recovered and six moorings were deployed during rough weather. The deployment of the mooring on top of Maud Rise had to be cancelled because of ongoing bad weather. At 60°S a section to the southeast was planned to identify a northward branch of the Weddell Gyre flow. This branch was deduced from earlier measurements, resulting in a much stronger gyre transport at the Greenwich Meridian than off Kapp Norvegia. Due to bad weather this plan had to be abandoned. To resolve the frontal system XBTs were launched between CTD stations from 57°S on northward. During ANT XV/4 the Weddell Front was located further south than during earlier surveys. The progress of circumpolar water induced a significant warming at the level of the Warm Deep Water, in contrast to the cooling observed at the southern part of the transect. Compared to earlier cruises, few icebergs were observed along the transect; none of the few was suited to deploy a buoy as planned. The section continued along the Greenwich Meridian as far as 48°S. There, it turned to the northeast. The last station (No. 136) was carried out at the Subtropical Front at 39°25'S, 11°48'E. XBTs were launched and ADCP data were recorded up to the 200-sm zone of South Africa. The cruise ended on 23 May 1998 in Cape Town. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 Preliminary Results The measurements along the Joinville section, spanning the outflow from the southern Weddell Sea into the Weddell- Scotia Confluence, display features comparable to those observed during earlier surveys (Fig. 7a and 8). The surface waters are relatively warm, in accordance with the autumnal situation. The thermocline from the Winter Water to the Warm Deep Water is deeper than in 1996, resulting in a temperature decrease at 500 m depth. The depression of the thermocline at the boundary of the gyre corresponds to an intensification of the boundary current. The temperature of the Warm Deep Water above the upper continental slope increased by as much as 0.1 K since 1996. This warming trend is not evident between stations 16 and 19, where the complete water column, except the surface water, is colder than in 1996. This is consistent with an intensification of the boundary current which, in this area, is deflected into the Powell Basin. On the slope the Weddell Sea-Bottom-Water layer is subject to strong spatial variation. Therefore, a trend analysis requires further effort. The quasi-meridional sections east and west of the South Orkneys across the Weddell-Scotia Confluence (Fig. 7a, 9 and 10) indicate that the band of Warm Deep Water with temperatures above 0.6°C penetrates into the Powell Basin and recirculates along the continental slope of the South Orkneys to the southeast. The temperature increase of the Warm Deep Water is clearly visible between stations 19 and 21. Here, the section reaches the southern part of the boundary current which has made its way through the Powell Basin and follows the southern continental slope. At the South-Orkneys-east section the current band is located between stations 34 and 38 (Fig. 9). Across the ridge extending from Joinville Island to the east, Weddell Sea Bottom Water enters the Powell Basin and fills the near-bottom layers with water colder than -1°C (Fig. 10). Comparable temperatures occur at the Joinville section on the continental slope below 1000 m, but are not observed at the South-Orkney-east section. There, the coldest temperatures of -0.8°C appear at the foot of the continental slope. At the boundary of the Powell Basin to the Soctia Sea near-bottom water at a depth of approximately 1500 m reaches temperatures of only -0.3°C (Figs. 7a and 11). We conclude that shallower parts of the bottom water enter and leave the Powell Basin before the western end of the Powell Basin-boundary section. Consequently, there is direct outflow of bottom water into Bransfield Strait. Bottom water colder than -1.O°C, observed at the Joinville- Island section between 1500 and 3000 m (i.e. at a depth greater than the sill depth), is not observed further to the north or to the east. To cross the sill, this water must be modified through mixing. The spreading of the isolines on the slope of the Powell Basin (Fig. 10) suggests that the bottom water, injected into the Basin along the slope, mixes with adjacent water masses. Consequently, the water with temperatures around -0.3°C, found in the Powell Basin, contains a significant amount of Weddell Sea Bottom Water. Since this water mass fills the southern slope of the trench north of the Powell Basin to a depth of 5000 m, a significant amount of Weddell Sea Bottom Water must be mixed, so that it can leave the Weddell Sea through the Powell Basin as a relatively shallow water mass. It is still dense enough, however, to fill the deep basins of the South Scotia Trench. Since in this area the temperature of the Warm Deep Water decreases towards north, it must have originated in the Weddell Sea. The meridional section along the Greenwich Meridian, extending from the ice shelf front at 69°38.5'S to 55°S, shows the well known structure of the Weddell Gyre: a central dome of cold water and descending isotherms towards the northern and southern edges (Figs. 7a and 12). Compared to 1996 the flanks of the dome became steeper. North of Maud Rise the slope is particularly steep, corresponding to a strong current to the west. The geostrophic currents and the results from current meter mooring 229 agree well in that sense. Within a band of 100 km width a volume transport of about 20 Sv to the west was derived. Further contribution to the westward transport results from a less intensive current band south of Maud Rise, and from the Antarctic Coastal Current. The steepening of the slope of the isotherms north of Maud Rise leads to a cooling of the southern part of the gyre. On the northern side of the gyre intensive mesoscale structures were found. The correlation with the bottom topography and the northeastward direction of the currents suggests topographically induced meanders. During earlier surveys along the Greenwich Meridian no mesoscale structures of that intensity were found. On average the structures give origin to a warming on the section since 1996. The southward shift of the transition zone from the Antarctic Circumpolar Current to the Weddell Gyre from 1996 to 1998 might indicate the start of a new warming event for the interior. The section across the Antarctic Circumpolar Current, from the Weddell to the Subtropical Front at 39°25'S, 11°48'E, indicates that both the Weddell and the Polar Front were shifted towards the south. In 1996 these two fronts were already further south than in 1992. This southward shift may be due to inter-annual or seasonal variability or both. Since 1992 a significant warming of 0.25 K of the deep water near the bottom above the northern slope of the Southwest Indian Ridge was observed. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 1.5. PROBLEMS During the first half of the cruise the data were significantly better than during the second half. This was caused by bad temperature conditions in the lab container after the container door had been blown away. However, after four days, the lab container temperature was stable again, thanks to the successful repairing of the air-conditioning system by the technicians of the crew. 1.6. OTHER OBSERVATIONS OF NOTE none 2. UNDERWAY MEASUREMENTS The programme consisted of measurements from the ship using the CTD probe (Conductivity and Temperature with Depth) connected to a water sampler, XBTs (eXpendable Bathythermographs), and both ship-borne and lowered 2.1. NAVIGATION AND BATHYMETRY Navigational data was continuously analyzed. Stable heading data with an accuracy of 0.10 was provided by the MINS (Marine Inertial Navigational System), a combined navigation equipment based on a laser ring gyro. In order to get information about the drift and to calculate the course made good, a "Sky Fix System" GPS (Global Positioning System) was used. This differential GPS uses the communication satellites of the Inmarsat system to correct the absolute position. For navigational use and in combination of the bathymetric survey with the hydrosweep-system the two navigational aids (Gyro and GPS) are combined by use of a filter. Failures or position jumps of GPS were filtered and smoothed out. By this means a reliable and good description of the ship's movement is achieved. The accuracy of the ship's position in the 1 -second values is better than 50 m. 2.2. ADCPs (Acoustic Doppler Current Profiler) (See Appendix 2) A self-contained narrow band ADCP (Acoustic Doppler Current Profiler) from RD Instruments, San Diego, with 153.6-kHz transducers was mounted on the CTD. The instrument was lowered with the CTD, and every 300 m a current profile was measured. From the sequence of individual profiles, one full-depth profile was constructed. Near-bottom measurements were disturbed by bottom reflections. Towards the end of the cruise the instrument failed, and a close inspection of the instrument by RDI was required. Altogether 131 LADCP profiles were obtained. These were processed with a program supplied by the Institut for Meereskunde Kiel (J. Fischer and M. Visbeck, Deep Velocity Profiling with self-contained ADCPs, Journal of Atmospheric and Oceanic Technology, 10(5), 764-773, 1993). The vessel-mounted narrow band ADCP from RD Instruments, San Diego, with 153.6-kHz transducers worked continuously. The data will be processed in Bremerhaven by means of CODAS. 2.3. XBTs During the crossing of Drake Passage, along the transect from 62°28'S, 36°38'W to 65°45'S, 22°17'W, and along the transect at the Meridian of Greenwich starting at 57°S up to the 200-nm zone of South Africa 196 XBT-7 from Sparton of Canada ltd., London, Ontario were launched (Abb. 13, 14, 15 and 16, Appendix 3). The data were directly transmitted by satellite into GTS. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 2.4. WEATHER CONDITIONS Rüdiger Hartig, Herbert Köhler (DWD) "Polarstern" left Punta Arenas on 28 March 1998, heading towards the Antarctic Peninsula. The Drake Passage, known for frequent gale activity, was crossed under fair weather conditions. Winds from the west to northwest and occasional sunshine were observed. "Polarstern" reached the Antarctic Peninsula on 1 April. 1 to 11 April 1998, section from the Antarctic Peninsula into the central Weddell Sea at 66°S, 25°W Low pressure systems, developing leeward of the Antarctic Peninsula and moving east across the northern Weddell Sea, dominated the synoptic situation in the northwestern Weddell Sea. These lows had only minor weather activity over sea ice, but intensified with moderate snowfalls over open water. The wind reached gale force on 10 and 11 April. Otherwise westerly winds around force 5 prevailed. The temperature ranged from -2 to -12°C. The region between 50° and 40°W was up to 80% ice covered; 50% consisted of multi- year ice up to 3 m thick. Few climatological data are available for this region. Meteorological measurements at the stations on the Antarctic Peninsula are influenced by orographic effects. Measurements taken at the South Orkneys are affected by the westerly wind regime, and may not be representative for the weather near the Peninsula. A rough idea about the weather conditions is given in "The Antarctic Pilot, 4. Edit. 1974, Part C, Chap.1, 66ff". Based on this report, we expected an equal amount of easterly and westerly winds with forces smaller than 5 Bft. The mean temperature rises only a little above freezing in summer and drops to -15°C in winter. Although nearly no easterly winds occurred during ANT XV/4, no significant differences from the climatological values were evident. 12 April to 21 April 1998, Weddell-Scotia Confluence At the beginning of this period polar air with temperatures around -1O°C was advected by winds from the south and southwest with forces 4 to 7. Fields of broken sea ice with rapid development of nilas between the flows prevailed south of 61°S. The area around the South Orkneys was sea-ice free, except for some icebergs. From 16 to 19 April the weather changed to a strong northwesterly regime. Air with temperatures slightly above freezing was advected by winds of force 7. The warm air over colder water induced mist, fog, and drizzle. Three days with fog were observed, corresponding to 50% of the expected value according to the climate table of the station "Islas Orcadas Sur" (period 1971-1980). Towards the end of this period cold air was advected from the southwest. Wind measurements recorded during ANT XV/4 by "Polarstern" are displayed in Fig. 2. From 12 to 21 April northwesterlies with force around 6 Bft prevailed. The "Polarstern" data were compared with climatological data (April) of the "Islas Orcadas Sur" weather station (Fig. 3). Winds from the south, southwest, and west were observed more frequently than expected, and the average wind speeds were higher. The occurrence of northerlies was comparable to the climatological data. Easterlies were exceptional and are not displayed. 22 to 28 April 1998, sailing to Neumayer Station Southwestly winds with force around 6 prevailed. In the night from 25 to 26 April the low pressure system intensified rapidly as it moved from the sea ice to open water. Wind speeds increased to force 10, with gusts of force 12. With this southwesterly flow continental cold air (between -10 and -15°C) was advected far to the north. The sky varied between fair and cloudy. The ice coverage was about 90%: 70% of first-year ice and 20% of multi-year ice. 29 April to 21 May 1998, section along the Greenwich Meridian In the vicinity of the Antarctic coastline winds from the east and southeast with force around 7 prevailed, inducing a 3-m swell in the open water. The ice edge was encountered at 69°S. Temperatures ranged from -6 to -11°C. Progressing northward, westerly and northwesterly winds dominated (Fig. 4). Wind speeds increased to force 8 and more. No heavy gales (stronger than Bft 10) occurred. The winds produced an average swell of 6 m, but periods with gales lasting for several hours increased the swell to 10 m. North of 60°S both the water and air temperatures reached positive values. A few icebergs were observed as far north as 55°S. 21 to 23 May 1998, sailing to Cape Town On the way to Cape Town "Polarstern" reached the subtropical high pressure zone. Fair weather, westerly winds between forces 4 and 7, and temperatures gradually rising to 17°C were observed. "Polarstern" reached Cape Town on 23 May. VALIDATION AND APPLICATION OF A CLOUD MASKING ALGORITHM Norbert Schlüter (IUPF) During ANT XV/4 data were collected for the HYPAM C (remote sensing of hydrometeorological parameters by microwave radiometry in polar regions) project. This project is funded by the Deutsche Forschungsgemeinschaft and aims to develop a new algorithm for cloud masking using infrared and microwave data. First versions of the algorithm were tested during the cruise. Satellite data of the two satellite series DMSP (Defense Meteorological Satellite Program) and NOAA (National Oceanographic and Atmospheric Administration) were received to analyze atmospheric profiles. The DMSP satellites consist of the sensors OLS (Operational Line-scan System, two channels in the infrared and visible spectral range), SSM/I (Special Sensor Microwave Imager, 7 channels in the microwave range), and the microwave sounders SSM/T1 (Special Sensor Microwave Temperature) and SSM/T2 (Special Sensor Microwave Water Vapor). The NOAA satellites are equipped with an AVHRR (Advanced Very High Resolution Radiometer) with 5 channels in the visible and infrared spectral range. A total of 230 DMSP passes and 160 NOAA passes were stored. In order to overview this large data set (ca. 20 GByte), a catalogue with visible and infrared images, as well as images showing the sea ice concentrations were generated. Examples for the sea ice concentrations from a microwave sensor are given in Figs. 5 and 6. Meteorological data were collected to improve the analysis of the satellite data. The daily radiosonde measurements were supplemented by 37 additional launches. Because of the high temporal variability of the atmosphere they had to coincide with the DMSP passes. The radiosondes measure profiles of air temperature, relative humidity, and wind in heights up to 33 km. In order to validate the radiosonde measurements, the cloud top and bottom levels were observed with helicopters. The weather charts and the hourly synoptic observations (clouds, precipitation, sea ice, wind) were stored. The analysis focused on the application of an algorithm for cloud masking with infrared data. Ice concentration and the location of the ice edge were estimated using microwave data and an algorithm developed in IUPF. An iceberg, recently formed near the Larsen Ice Shelf, was monitored using cloud- free scenes from infrared and visible satellite images. The radiosonde data were compared with infrared satellite images. The cloud top level temperatures were in good agreement, especially in cases of homogeneous cloud cover. To fully exploit the potential of the obtained data set, more analyses are necessary. Selected infrared images will be visually classified and used to train a neural network for automatic classification. In addition, sequences of images will be analyzed to take advantage of the different dynamics of sea ice and clouds. The radiosonde measurements will be used to analyze the data of the SSM/T1 and SSM/T2 sensors. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 3. PHYSICAL OCEANOGRAPHY: DEEP AND BOTTOM WATER FORMATION IN THE WEDDELL SEA Eberhard Fahrbach, Martin Frenzel, Sabine Harms, Antonio Härter Fetter, Alexeij laremtchouk, Jens Langreder, Sven Loske, Katrin Meissner, Carlos Mir Casanovas, Matthias Monsees, Adriene Pereira, Gerd Rohardt, Michael Schröder, Andreas Wisotzki, Hannelore Witte (AWI, FURG, 1CM, IUPT) Objectives 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, sea ice formation, as well as the interaction between the ocean and the ice shelves induce water mass modifications, and water masses dense enough to sink to the bottom of the Weddell basin may be formed. 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. The outflow in the western Weddell Sea consists of near surface, intermediate, and deep components. The near surface water is, to a large extent, shelf water from the Weddell Sea which, in the area of the Weddell-Scotia Confluence, encounters waters from the Antarctic Circumpolar Current. The confluence gives rise to a system of two fronts, the Weddell and the Scotia Front. These fronts enclose a water mass whose properties result from the mixing of the converging water masses and the local atmosphere-ice-ocean interaction. If this water crosses the ridge system at intermediate depth and sinks along the front, it may contribute to the ventilation of the deep global ocean without ever having been bottom water in the Weddell Sea, the traditionally assumed ventilation area. The intermediate components consist of the upper part of the Weddell Sea Deep Water found in the central Weddell Sea below 1250 m. At this depth outflow may occur over large parts of the South Scotia and North Weddell Ridges. The deep components of the Weddell Sea water flow along the South Scotia Ridge to the east and escape through gaps to the north, where they fill the deep basins of the Atlantic and Indian Oceans. At the Greenwich Meridian the water masses, modified in the eastern Weddell Sea by injection of circumpolar waters, flow westward in the southern part of the gyre. In the north water modified in the gyre and newly formed bottom water recirculate to the east. During the past years the water coming from the Antarctic Circumpolar Current and the bottom water in the central Weddell Sea became gradually warmer. The regional distribution of the variations are used to examine if and how local variations of the atmosphere-ice- ocean interaction and the inflow from the north affect the bottom water formation. Of particular interest are variations affecting the stability of the water column and the atmosphere-ice-ocean interaction west of Maud Rise. Here, a large open ocean polynya was observed in the seventies, leading to open ocean formation of deep water. The transition of water mass formation processes over the continental slope to those in the open ocean could cause abrupt changes with effects on the global thermohaline circulation. The physical oceanography programme onboard is part of the international DOVETAIL project (Deep Ocean VEntilation Through Antarctic Intermediate Layers), a contribution to the SCOR affiliated iAnzone programme (Scientific Committee on Oceanic Research). In this context the instruments on the moorings in the western Weddell Sea are provided by the Universitat Politecnica de Catalunya in Barcelona, Spain. The cruise track in the Weddell-Scotia Confluence is partly a repeat of a survey carried out with the U.S. ice breaker "Nathaniel B. Palmer" in August 1997. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 3.1. BOTTLE DATA TECHNIQUES AND CALIBRATION 3.1.1. NUTRIENT DISTRIBUTIONS IN ANTARCTIC WATERS Karel Bakker (NIOZ) Equipment and methods Nutrients were analyzed by standard photometric methods on a Technicon TRAACS 800 rapid flow autoanalyser. The sample rate was set to 60 samples per hour, measuring about 3000 samples during the cruise. Measurements were made simultaneously on four channels: phosphate, silicate, nitrate and nitrite together, and nitrite separately. All measurements were calibrated with standards diluted in low nutrient sea water (LNSW). Subsamples from the CTD-Rosette were collected in 100-ml polyethylene sample bottles. The samples were kept cool and dark, and were generally analyzed within 12 hours. Sample statistics for stations 001 and 099/02 where all bottles were fired at one depth. | Station 001 | Station 099/2 |-----------------------------|-------------------------- | aver. | std. dev. | % | aver. | std.dev. | % | µmol/l | µmol/l | | µmol/l | µmol/l | --------|----------|-----------|------|---------|----------|----- P04 | 2.2895 | 0.0037 | 0.16 | 2.366 | 0.0043 | 0.18 Si02 | 131.86 | 0.72 | 0.55 | 128.03 | 0.297 | 0.23 N03+NO2 |<··········no data··········>| 34.48 | 0.065 | 0.19 Measuring ranges In order to increase the accuracy of the measurements, an attempt was made to scale in the range for the nutrients to be measured so that the maximum was always at a level of 80- 90% of full scale. This resulted in acceptable percentage standard deviations for reproducibility of 0.18% for P04, 0.23% for Si02 and 0.19% for N03+NO2 as a percentage of those levels. Calibration and standards Nutrient primary stock standards were prepared at the home lab. The calibration standards were prepared daily by diluting the stock standards, using three electronic pipettes, into four volumetric 100-ml PP flasks (calibrated at the lab) filled with low nutrient sea water (LNSW). The values of the LNSW were measured on board and added to the calibration values to get the absolute nutrient values. Cocktail standard This standard acts as a reference. It is made in the home lab containing phosphate, silicate and nitrate in a solution containing 40 mg H92CI2 per litre as a preservative. Every time it was used, it was diluted 100 times with the same 1- ml pipette and the same volumetric 100-ml flask. In inter-calibration exercises like ICES and Quasimeme our standards were within the obtainable limits to the mean of the better laboratories. There is still no absolute reference standard available, so an onboard comparison was made (to gain accuracy) with the stock standards of Ocean Scientific International OSI. Our results listed in the next table are given as 100%. | ANT XV/4 | OSI -----|----------|------- P04 | 100.0% | 99.8% Si02 | 100.0% | 100.3% N03 | 100.0% | 99.6% ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 The other stocks compared well with OSI stocks. Another comparison was carried out by measuring deep water from the Weddell Sea sampled in 1996 and the cocktail standard used in that year. Comparison with Weddell Sea water of 1996 and the cocktail of 1996: | P04 µmol/l | Si02 µmol/l | N03 µmol/l |-------------|----------------|------------ | 1996 | 1998 | 1996 | 1998 | 1996 | 1998 Weddell Sea. | 2.39 | 2.34 | 126.6 | 126.35 | 34.1 | 34.2 Cocktail 1996 | 2.92 | 2.84 | 83.0 | 83.1 | 35.8 | 35.7 1998/1996 ---------------------------------------------------------- Weddell Sea | 98.0% | 99.8% | 100.3% Cocktail 1996 | 97.3% | 100.1% | 99.7% The data for Si02 and N03 for 1998 compare well with those of 1996. However, the P04 data of 1996 must be corrected with a factor 0.98 due to the fact that the calibration standard used in 1996 was only 98%. This was independently confirmed by an intercomparison (Quasimeme) and by calibrating against 100% pure potassium dihydrogen phosphate. Cocktail standard statistics To obtain cross run statistical values for a limited number of stations, analyses were carried out twice on the same sample from the bottle closed in the bottom layer. This gives the possibility to estimate the precision from station to station. Analyses of these "real" (cross runs) duplicates show the absolute differences for P04 to be 0.013 pM, for Si02 to be 0.80 pM and for N03+NO2 to be 0.20 pM in the raw data set. During all runs an independent "reference" standard (the cocktail) was measured as a triplicate. From all of these measurements the average value was recorded. If we assume that on this level the value of the cocktail does not change during the different cruises, then, by dividing the average of the end by the average of the different runs, we obtain a factor for all three parameters which can be multiplied with the data of that particular run to obtain corrected data. As a check on the data we again looked at the absolute differences between the "real" 96 duplicates with the following results: | C.V.% (of average | µmol/l | value sample) --------|----------------------|----------|---------- | original | corrected | original | corrected P04 | 0.0131 | 0.0097 | 0.60% | 0.44% Si02 | 0.80 | 0.57 | 0.70% | 0.47% N03+NO2 | 0.197 | 0.158 | 0.60% | 0.48% Clearly, there is a significant improvement for phosphate, silicate and nitrate. The cocktail standard is a reference standard with the three nutrients mixed into one bulk, giving for each run an idea of how the machine is performing. It is also an instrument to correct data from run to run for producing better data quality, especially in an area like the Weddell Sea where nutrient gradients in deep water are very small. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 3.1.2. CFCS, HELIUM AND TRITIUM Klaus Bulsiewicz, Gerhard Fraas, Oliver Huhn, Olaf Klatt and Christian Rodehacke (IUPT) Objectives and methods CFCs, Tritium and partially 3 He are transient tracers of anthropogenic origin. Measured distributions of these tracers provide information on the renewal of subsurface water from the ocean surface layer on yearly to decadal time scales. Sections investigated during ANT X/4 (1992) and ANT XIII/4 (1996) were repeated to evaluate the increase of the tracer concentrations in time. The comparison between the atmospheric and the in-situ increase will be used to study transport processes. The natural tracers 3 He and He will also be used to identify the water mass ventilation from the surface layer and the contribution of Ice Shelf Water. Along the sections, the CFCs Freon-11, Freon-12, Freon-113 and CCL4 were measured on board by ECID gas chromatography. In addition to the analyses on board, water samples for CFC were stored in flame-sealed ampoules which will be analyzed in the laboratory. Water samples for Helium and Tritium were also taken. They will be extracted after the cruise and analyzed 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, that it can be measured by the mass spectrometer. Work at sea At the hydrographic section in the western Weddell Sea, water samples for CFCs and CCL4 were taken from the rosette water sampler using flow-through containers. Along the Greenwich Meridian, from the ice-shelf edge at 69°24'S to 50°S, only the CFCs Freon-11 and Freon-12 could be measured. Water had intruded into the freon system and damaged the capillary column of the gas chromatograph. With a new column (however, a different type as the old one) it was not possible to measure Freon-113 and CCL4. Helium (copper tubes) and Tritium (glass bottles) were also taken from the water sampler rosette. In addition to the helium samples in copper tubes, water samples were stored in flame-sealed ampoules. These samples will also be analyzed in the laboratory and will provide reference measurements for the water samples in copper tubes. In total, 106 stations were sampled and 1600 water samples for the CFCs were analyzed during this cruise. In addition, 850 gas and blank measurements were taken with constant time intervals. Air samples were frequently analyzed to establish the atmospheric CFC and CCL4 concentrations. They will be used to calculate the CFC and CCL4 saturation of the surface water. In total, 1850 water samples were collected for analyses in the laboratory, including 350 CFC water samples in glass ampoules (collected at 28 stations), 667 water samples for Helium in copper tubes (collected at 66 stations), 260 water samples in glass ampoules (collected at 33 stations) and 571 samples for Tritium (at 60 stations). At a test station at the Greenwich Meridian at 64°30'S no CFC-free water was found, so that the blank levels of the bottles could not be established. These samples (all in the same depth of 1300 m) and replicate samples frequently drawn throughout the cruise do not exhibit any suspicious variability. Therefore, we are confident that the bottles did not contaminate the CFC samples. Another test station was made in the Cape Basin at 42°S, 6°5'E (all bottles in the same depth of 3000 m). These samples were stored in flame-sealed ampoules for analyses ashore. The water obtained at this depth is very old (Freon-11 < 0.05 pmol/kg) still above the detection limit of 2 to 3 fmol/kg. Therefore, the measurement of this samples gives additional information about the variability due to contamination of the bottles. Preliminary Results The section across the southern Weddell Gyre, extending from the Antarctic Peninsula (Joinville Island) to 25°W, is shown in Fig. 20 (top). The layer of the high CFC concentration along the slope of the Antarctic Peninsula indicates newly formed bottom water which flows to the north. Relatively old water, enclosed by the 0.15 pmol/kg isoline, is located at a depth between 500 and 2000 m as found during ANT XIII/4 (1996). The section from Antarctica (69°24'S) along the Greenwich Meridian to 50°S is shown in Fig. 20 (bottom). Observations along this section can be compared with data from previous cruises (ANT X/4 in 1992 & ANT XIII/4 in 1996). In the centre of the Weddell Gyre (62°30'S) water with less than 0.2 pmol/kg reaches to a depth of 2000 m. In 1996 it reached to 2500 m and in 1992 to 3500 m. The increase of the tracer concentration in the interior from below is consistent with upwelling in the Weddell Gyre. On the continental slope, a core of young water (0.75 pmol/kg) occurs at 3300 m. This was also found during ANT XIII/4. The source of this water is further to the east. The core of young water, leaning against the southern flank of the Southwest Indian Ridge, shows the flow of Bottom Water moving from the western Weddell Sea to the east. The relatively high CFC concentrations (> 0.6 pmol/kg) on the southern and northern slope of Maud Rise were higher in comparison to the previous cruises. The cause of the increase of the CFC concentration is not clear at this time. The section extending from the Weddell Basin at 65°S across the South Orkney Plateau to 59°30'S is shown in Fig. 21 (top). In the Weddell Basin, at depths deeper than 4500 m at approximately 64°S, we found CFC concentrations with Freon- 11 > 2.0 pmol/kg. Similar CFC concentrations occurred in the Jane Basin at depths deeper than 3500 m. The source area of this well ventilated bottom water is near the northern part of the Antarctic Peninsula. The section across the Powell Basin is presented in Fig. 21 (bottom). Near the centre of the Powell Basin (62°30'S) a maximum in Freon-11 concentration (> 2.0 pmol/kg) occurs at a depth of more than 3000 m. This is also newly formed bottom water from the Antarctic Peninsula which follows the topography and spreads into the Powell Basin. North of the South Scotia Ridge we found, on the slope and at the bottom, Freon-11 concentrations > 1 pmol/kg. This bottom water circulated counterclockwise around the South Orkney Plateau and has been mixed with "older" water with lower CFC concentrations. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 3.1.3. THE CARBON DIOXIDE SYSTEM IN ANTARCTIC WATERS Mario Hoppema (IUPB) and Richard Bellerby (PML) 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 (CO2), 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 CO2, 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 CO2 uptake and its distribution. The objective of this project is to gain knowledge of the CO2 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 CO2. 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 Work at sea CO2 parameters have been investigated along sections across the Weddell Sea, two sections across the Weddell-Scotia Confluence, and a long section from the Antarctic continent to the African continent largely following the prime meridian. Parameters that were measured include the total inorganic carbon content (TCO2) and the partial pressure Of CO2 (pCO2). Vertical TCO2 profiles of the entire water column were determined from discrete water samples taken from the Rosette sampler. The pCO2 was determined quasi- continuously from the sailing ship, only in the surface water. TCO2 was determined by a high-precision coulometric method using an 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 extracted CO2 is, with a carrier gas (pure N2), passed through a solution containing ethanolamine and an indicator. This solution is electrochemically back-titrated to its original colour and the amount of Coulombs generated is equivalent to the amount of CO2 in the sample. The measurements are calibrated and corrected against an internationally recognized TCO2 standard (Dickson). Continuous measurements of the pCO2 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 CO2 content, thus giving pCO2 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 measurements are calibrated with reference gases, traceable against NOAA standard gases. Final data will be available after re-calibration of the reference gases ashore. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 PRELIMINARY RESULTS Total carbon dioxide In Fig. 22 the section across the Weddell Sea between Joinville Island (near the tip of the Antarctic Peninsula) and the central Weddell Sea is shown for TCO2. A general feature of the TCO2 distribution is that, although the TCO2 values in the Weddell Sea surface water are high compared to other surface ocean regions, they are low in comparison with the deep and bottom water. The TCO2 minimum in the surface water is due to phytoplankton which utilises CO2. Below the thermocline, a TCO2 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 TCO2 values were measured. This water mass originates partly from the shelf waters of the Weddell Sea, which are low in TCO2. 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 TCO2 values. Over the. continental slope of the Antarctic Peninsula a thin layer of recently formed bottom water was observed, recognizable by its low TCO2 values. This coldest Weddell Sea Bottom Water of the Weddell region also has the lowest TCO2 values. Towards the coastline the isolines fall precipitously indicative of a sharp frontal feature. This is the Antarctic Slope or Shelfbreak Front, which separates the Warm Deep Water and Antarctic Surface Water from the coastal and shelf waters. The TCO2 maximum is the highest towards the central part of the Weddell Sea. In fact, the values observed here are higher than those of the Warm Deep Water that enters the Weddell circulation near 25°E. This implies that in the central Weddell Sea CO2 enrichment of the Warm Deep Water occurs, which is most probably caused by the decomposition of organic material at that depth. Partial pressure Of CO2 The measurement Of pCO2 during the entire cruise period resulted in a large, high spatial resolution data set. Only modest under- and supersaturation were observed in the area of investigation. The spatial variability in this time of the year was found to be relatively small, which is probably related to the low level of biological activity in the surface layer. The only exception being the shelf area of the South Orkney Plateau. Frontal structures were generally reflected in the pCO2 distribution. As an example the pCO2 across the Sub- Antarctic Front on the prime meridian is shown in Fig. 23. South of the front in the Polar Frontal Zone the pCO2 is relatively constant and above saturation. On passing the front a clear pCO2 change from supersaturation to under- saturation was observed on a small spatial scale. Also shown in Fig. 23 is the surface temperature along this transect. Clearly, the pCO2 signal is strongly negatively correlated with the temperature change across the front. Note that in general the correlation between the pCO2 and the surface temperature is very high. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 3.1.4. METHANE AND THE 12C/13C RATIO Katja Heeschen und Karin Fürhaupter (GEOMAR) Objectives and methods The atmospheric trace gas methane has increased in the last 150 years from about 700 to 1800 ppbV. At the sea surface the concentration is in equilibrium with the atmospheric content of methane. Changing atmospheric gas concentrations result in a time dependent increase of methane in the ocean. This signature should be observed in recently formed deep waters. The pattern in the water column should be similar to those of transient tracers (e.g. Tritium, CFCs). Methane is influenced by the atmospheric content as well as by production and consumption within the ocean. The measurement of the 12C/13C ratio of the dissolved CH4 Will provide an indication of the extent of the methane decrease in the water column that is due to oxidation, because this process preferentially consumes the lighter isotope. On the other hand, the carbon isotope ratio of methane in the atmosphere has remained nearly constant over time. The goal of this investigation is to separate the effects of uptake from the atmosphere and microbial oxidation on the distribution of dissolved methane. For this purpose we determined the methane content and the stable carbon isotopic ratio in the younger bottom water of the Weddell Sea and in the water masses of the Weddell-Scotia Confluence. This will lead to a larger data base of methane concentrations in the Weddell Sea and will also be used for comparison with the distribution of common transient tracers to develop a model for the methane budget in higher latitudes. In order to measure the dissolved methane, water from the bottles is drawn into a 200-ml glass syringe two times without contact to the air. The syringe is then connected to an evacuated 500-ml bottle. As the water is drawn into this bottle from the syringe, most of the dissolved gas separates from the liquid phase. The gas is then led into an evacuated burette and compressed to atmospheric pressure by injecting a degassed brine into the bottom of the sample through a sidearm. Subsequently, 1 ml of gas is extracted and injected into a gas chromatograph equipped with a flame ionization detector (FID) to determine the mole fraction of methane in the extracted gas. The gas remaining in the burette is collected in an evacuated vial for isotopic analysis by mass spectrometry ashore. 2188 samples were taken at 4 hydrographic sections and 119 rosette stations to measure the methane content in the water column on board. The accuracy of the method (4%) was determined at two test stations where all bottles were closed at the same depth. The accuracy of the gas chromatograph (3%) was determined by using a CH4 standard in synthetic air which was calibrated to ±0.1% (methane concentration. 1.936; Department for Environmental Physics in Heidelberg) for 375 times. 1306 gas samples were taken from the extracted gas of the discrete water samples in order to measure the isotopic signal of methane after the cruise in a shorebased mass spectrometry laboratory. The samples are stored in evacuated gas-tight vials (5 ml). Those samples can be determined much faster than water samples which leads to a larger data base. Because this method is expected to be less exact than immediate extraction from water samples before analysis, 84 double samples were stored in 100-ml gas-tight headspace vials. Those specimen will be extracted ("purge and trap" method) and measured with the GC-C-IRMS method (Gas Chromatography- Combustion- Isotopic Ratio Mass Spectrometry method) at the lab for comparison with the gas samples extracted on board. The water samples are stored at temperatures of 4°C. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 Preliminary results A vertical transect from the Antarctic Peninsula to 250W (Section 1, Fig.24) shows high values of methane (up to 2 ppbV and more) at the continental slope of the Antarctic Peninsula up to a depth of 3000 m. They can be correlated with the ventilated water from the southwestern shelves of the Weddell Sea which is transported northwards along the slope. Due to the relative new Weddell Sea Bottom Water, higher contents of methane can also be seen at the bottom of the Weddell Basin (0.6250.894 ppbV) in comparison with the concentration measured in the central part (0.395-0.679 ppbV). Where Warm Deep Water is dominant, methane concentrations of the Bottom Water are much lower than the ones at the slope. In contrast, Warm Deep Water shows enhanced methane concentrations compared with very old water masses in the South Shetland Trench (0.4 ppbV; measured on ANT XV/2). Contents of about 3 ppbV of methane in the surface water confirmed the assumption that the concentration of methane in the surface water in higher latitudes is controlled by the partial pressure of methane in the atmosphere. East of the South Shetland Islands (Section 2, Fig. 25) higher concentrations of methane occur north and south of the Endurance Ridge (Jane and Weddell Basin). Near the bottom, values of 1.467-1.718 ppbV are observed in a few hundred meters thick layer. It results from recently ventilated water from the western Weddell Sea transported northwards. Slightly higher concentrations (1.269 ppbV) occur at the bottom in the trench north of the South Orkney Plateau which is more than 5000 m deep. An unexplained feature was found in the subsurface water above and north of the plateau. Local concentrations of methane are up to 5.336 ppbV at a depth of 100 m. Anoxic mircohabitates in particles and microorganisms could be a reason for this subsurface maximum. In the trench north of the South Scotia Ridge with depths of more than 5000 m relatively high values (up to 1.301 ppbV) of methane are found (Section 3, Fig. 26). Even in shallower areas concentrations above 1.2 ppbV were measured. A water mass with up to 1.823 ppbV at the bottom of the Powell Basin indicates recently ventilated water from the continental shelf of the Antarctic Peninsula. It is transported northward through the basin. South of the Powell Basin this water mass can be found with values of 1.95 ppbV in 2000 nm depths. The central basin contains an older water mass low in methane up to 1000 m depth with a core value of more than 0.6 ppbV. As seen in section 2 there is some oversaturated surface water with maximae in 50 m depth at a few stations. Transect 4 along the Greenwich Meridian is not yet processed completely. However, preliminary results show methane concentrations up to 1 ppbV at bottom of the Antarctic continental slope. During the continuation of the transect a rather uniform distribution of methane (0.5 to 0.8 ppbV) was observed. Difficulties with the equipment require the correction of the data. Values at the sea surface are in equilibrium with the atmosphere. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 3.2. CTD MEASUREMENTS AND CALIBRATION Equipment The hydrographic work was carried out using CTD probes and water bottle release mechanisms built by Falmouth Scientific Instruments (FSI). Two instruments of the type Triton ICTD, SN 1347 and SN 1360 were used. The water samples were taken with a 21-(12-1)-bottle rosette from General Oceanics Inc.. The accuracy of the data set is determined by laboratory calibrations both before and after the cruise. Each CTD is equipped with two temperature sensors. The stability of these sensors is controlled by comparing both readings. For both instruments the calibrations before and after the cruise were performed by the Scripps Institution of Oceanography. For both sensors the temperature drift in the relevant temperature range was less than 1 mK. Thus, the pre-cruise calibration coefficients were used. Quality control onboard the ship was performed using 7 electronic thermometers from SIS (SIS Sensoren Instruments Systeme GmbH, Kiel), calibrated by the manufacturer. Deviations from the sensor readings occurred due to scatter in the thermometer readings. If noise is taken into account the sensors' accuracy amounts to 2 mK. For both CTDs pressure calibrations were performed before and after the cruise at Scripps. No change was recorded between the pre- and post-cruise calibrations. The accuracy of the pressure readings is better than 2 db. Quality control onboard the ship was performed using 7 electronic pressure gauges from SIS (SIS Sensoren Instruments Systeme GmbH, Kiel). The instruments were calibrated by the manufacturer. The conductivity was corrected using salinity measurements from water samples. IAPSO Standard Seawater from the P- series P133 was used. A total of 2649 water samples were measured using a Guildline Autosal 8400B. On the basis of the water sample correction, salinity is measured to an accuracy of 0.002. To determine distance above the sea floor, the CTD was equipped with an altimeter from Benthos Undersea Systems Technology Inc. Two transmissometers with a 25cm light path from SeaTech Inc. were used, but after a few stations both were damaged by water leaking. At all stations oxygen samples were taken from the entire water column (in total 2915 samples). The determination of oxygen was carried out according to WOCE standards for 02 measurement (Carpenter, 1965). Two radiation counters from SIS (SIS Sensoren Instruments Systeme GmbH, Kiel) were used. 346 double samples, amounting to 10% of the samples and covering the entire range Of 02 values (180 350 µmol/l), were taken. Using these data, a percentage error of 0.1% was obtained. Oxygen profiles were not measured because oxygen sensors fail under freezing conditions. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 Calibration CTD Measurements during 06AQANTXV/4 Instruments: Falmouth Scientific ICTD, Sn: 1360 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 ICTD-SN 1347; Cal_date: AUG.98 Calibration: post-cruise no pre-cruise calibration used #PT1 a1 = 0.00179275 a2 = 0.000367769 a3 = 5.98102E-06 a4 =-1.73705E-06 a5 = 3.92021E-08 #PT2 a1 =-0.00296646 a2 = 0.000105862 a3 = 1.00638E-05 a4 =-1.12480E-06 a5 = 2.20040E-08 temperature post-cruise calibration the temperature data are used only from PT2 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 = 1.6215 a2 = 0.000766727 a3 =-2.36597E-07 a4 =-5.02071E-11 a5 = 8.88206E-15 #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 ai : p(calibrated)-p(reading) ICTD-SN 1360; Cal_date: AUG.98 Calibration: post-cruise no pre-cruise calibration used #PT1 a1 = 0.00448876 a2 =-4.55829E-05 a3 = 3.83954E-05 a4 =-2.45250E-06 a5 = 4.40105E-08 #PT2 a1 =-0.00332538 a2 =-0.000208227 a3 = 3.21668E-05 a4 =-1.67948E-06 a5 = 2.77787E-08 temperature post-cruise calibration the temperature data are used only from PT2 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 =-0.641264 a2 =-0.000848878 a3 = 3.51877E-07 a4 =-7.04156E-11 a5 = 4.47779E-15 #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 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 constant in seconds relative to the fast thermistor TtauF = 400 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)) ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 Station/Cast COND(delta) -------------- ----------- 00101 to 00601 -0.0149 00703 -0.0138 00801 to 00901 -0.0136 01001 -0.0130 01102 to 01106 -0.0129 01201 -0.0131 01301 -0.0130 01401 -0.0133 01501 to 01502 -0.0129 01601 -0.0131 01701 -0.0132 01801 -0.0128 01901 -0.0134 02001 to 02002 -0.0135 02101 -0.0136 02201 to 02801 -0.0134 02901 -0.0138 03001 to 03101 -0.0140 03201 -0.0135 03301 to 03401 -0.0134 03501 -0.0135 03601 -0.0134 03701 -0.0130 03801 -0.0128 03901 -0.0127 04001 -0.0126 04101 -0.0129 04201 -0.0124 04301 -0.0121 04401 -0.0130 04501 -0.0127 04601 -0.0133 04701 to 04702 -0.0117 04801 -0.0116 04901 -0.0113 05001 -0.0115 05101 -0.0120 05201 to 05301 -0.0121 05401 -0.0119 05501 -0,0168 05601 to 05701 -0.0158 05801 -0.0145 05901 -0.0140 06001 -0.0137 06101 -0.0140 06201 -0.0141 06301 -0.0143 06501 -0.0141 06601 -0.0144 06701 to 06802 -0.0140 06901 -0.0139 07001 to 07101 -0.0142 07201 to 07301 -0.0144 07401 -0.0142 07501 -0.0144 07601 -0.0145 07701 to 07702 -0.0146 07802 to 07804 -0.0147 07901 -0.0149 08001 -0.0148 08101 -0.0150 08201 -0.0149 08301 -0.0151 08401 -0.0149 08501 -0.0150 08601 -0.0153 08701 to 08901 -0.0149 09001 -0.0147 09101 -0.0145 09201 -0.0143 09301 -0.0150 09401 to 09601 -0.0151 09701 -0.0153 09801 -0.0152 09902 to 09905 -0.0150 10001 -0.0151 10101 -0.0153 10201 -0.0150 10301 -0.0148 10401 -0.0150 10501 to 10601 -0.0151 10702 to 10704 -0.0150 10801 -0.0152 10901 -0.0150 11001 -0.0151 11101 -0.0150 11201 -0.0149 11301 -0.0150 11402 to 11404 -0.0148 11501 -0.0149 11601 to 11701 -0.0150 11801 -0.0148 11901 -0.0142 12001 to 12101 -0.0144 12201 to 12202 -0.0148 12301 to 12401 -0.0140 12501 to 12601 -0.0147 12701 -0.0148 12801 -0.0146 12901 -0.0144 13001 -0.0141 13101 -0.0144 13201 -0.0145 13301 to 13401 -0.0149 13501 -0.0154 13601 -0.0147 CTD Files column 5 : transmissiometer raw data range between 0 and 5 Volt these data are not controlled ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 4. MARINE BIOLOGY 4.1. DECOMPOSITION OF SINKING PARTICLES Anja Heuchert (UFT) Objectives Macroscopic aggregates (marine snow) are the dominant fraction involved in the transport of biogenic carbon from surface water to the deep-sea bottom. Rapidly sinking particles in the water column, so called "marine snow", consist of dissolved and colloidal organic matter which aggregates together, e.g. phytoplankton aggregates, fecal pellets and detritus. Bacteria and protozoa seem to play an important role in decomposing "marine snow", because the main decomposition takes place in the mesopelagic zone. In this investigation, single strains of bacteria attached to "marine snow" will be isolated. By means of these isolates, the microbial decomposition of "marine snow" by different species of bacteria will be investigated. In addition, preparations for light and electron microscopy will be made. Moreover, the fixed material has to be examined with a scanning electron microscope to determine the colonization with attached bacteria. The results will be compared with those of two cruises in the equatorial Atlantic in 1996 and 1997. Work at sea In order to investigate the colonization of sinking particles in the water column, ("marine snow") samples from different water depths were taken with bottles at 16 stations. Pure strains of attached heterotrophic bacteria were isolated from samples which were filtered through 5-µm or 10-µm pore-size filters to increase particle concentration. Water samples from sediment trap 227-4 were taken to investigate bacterial density. Furthermore samples are filtered through 0.2-µm and 5-µm or 10-µm pore-size filters and fixed for 30 min in 3.7% formalin. This fixed material will be used for the in-situ identification of microorganisms. Fluorescently labeled rRNA-targeted nucleic acid probes allow an in-situ identification of individual microbial cells in their natural habitat. In order to quantify the bacteria, samples taken by the ship's pump and filtered through 11-µm pore-size filters were fixed with formalin (2% v/v). Later the samples will be treated with the epifluorescence dye DAPI in order to count the bacterial cells of the free water column as well as the attached bacteria. Preliminary results The filtered particles were rather small in most of the cases and hardly visible on the filter itself. However, five different strains of bacteria have been distinguished with respect to colony- and cell morphology. Two of the strains were found at one particular station only, whereas the others occurred at various stations during the cruise. All of the obtained bacteria are rods, some of them are motile rods. It is intended to investigate the metabolism of the isolates and characterize them thoroughly. As has been stated before, a quantitative count of bacterial cells will have to be performed at the lab using the epifluorescence dye DAPI. Furthermore, there will be an in-situ identification of the bacteria at the lab. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 4.2. MICROBIAL COMMUNITY CHARACTERISTICS IN AUSTRAL AUTUMN FROM ICE AND SEA WATER. Kjell Magne Fagerbakke (IM) Objectives The role of sea ice as an environment for growth and survival of microorganisms in the Weddell Sea is characterized by measuring Chlorophyll a and DOC/POC (Dissolved organic carbon/particulate organic carbon) concentrations in ice and sea water. Measurements of DOC may increase our knowledge of the biological input in CO2 sequestering from the atmosphere. A large contribution to it may come from the POC produced in sea ice. Elemental compositions of microorganisms are shown to reflect their growth. If this is the case for microorganisms living in nutrients, excess (N, P) is explored by X-ray microanalysis (XRMA). From XRMA a physiological characteristic can also be made. Variation within and among the microbial communities in sea water and ice may be discovered. Work at sea The sampling routine was to make one station each day (in total 48). Samples of chlorophyll from 0, 20 and 100 m have been taken. Samples of POC and DOC were made from the same stations as Chi. a. All Chi a, POC, and DOC samples were frozen to be analyzed later. When sea ice was present, ice samples were taken. From the ice Chi a, POC, and DOC were also taken (in total 10 stations). The communities present, both in sea water and ice, were characterized by fluorescence microscope. Preliminary results The brown layers of first-year sea ice consist mostly of particular matter and only occasionally algae were observed. Variation in species composition indicated that different algae had different strategies for the life in ice. The dominating species in compact ice were Stellarima microtrias and Dactyliosolen Antarctica, indicating that these algae are staying until the ice melt. Occasionally observations of Corethron criophilum in ice, and always in porous ice, indicate that this specie may easier leave the ice than the former. From the structure of ice it seems that large holes may be created during the melting period and due to this, the algae may migrate easily to the open water. Possibly algae influence the ice melting, and species found in winter ice, but not in spring ice are more effective in the melting process than C. criophium. C. criophilum was also observed as one of the dominating species to occupy the new ice, when it is formed. During growth of artificial sea ice, phosphorus was not incorporated, and at the time of incorporation the organisms may explore phosphorus depletion. Nitrate and silicate levels decreased during the ice formation also. However, the level of 20 to 30 RM silicate and 10 [tM nitrate may be sufficient for biological activity based on this as limiting factors. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 4.3. THE ROLE OF SPONGES IN CARBON AND SILICON FLUXES IN THE WEDDELL SEA Susanne Gatti (AWI) Objectives Flow of carbon: Antarctic sponges are supposed to grow very slowly due to low ambient water temperatures and scarce, seasonally strongly varying food supply. As sponges do not build any permanent hard skeleton parts it is impossible to assess their age by analyzing such structures. Turn over rates for spicules in Antarctic sponges are not known and as for now no method exists that utilises the siliceous sponge spicules for age analysis. It is therefore impossible to assess growth or age via direct methods as for example in some mollusks, echinoderms, or fishes. To provide a rough estimate of growth rates and the age of sponges, mass specific respiration rates will be established. After conversion, these will provide estimates of consumption and production rates. Flow of silicon: In the Antarctic the silicon cycle in the water column has been studied extensively. Thus, the role of diatoms, radiolarians, and silicoflagellates is quite well understood. But so far no effort has been made to study the role of sponges in the silicon cycle. Frequently, up to 90% of the wet weight of siliceous sponges (Demospongia and Hexactinellida) consist of opal (biologically synthesized silica) (Barthel, 1995). As methods for age determination in sponges are lacking it is impossible to assess how long it takes for a sponge to accumulate these enormous amounts of opal. Work at sea Most of the animals were collected during the previous leg (ANT XV-3). Additionally, two Agassiz trawls (AGTs) were used off Kapp Norvegia during this leg to collect fresh sponges for analysis of activity of the electron transport system (ETS). Long term (more than three months) life maintenance of the collected sponges was successful. Individuals collected during the previous leg were in good condition. Meanwhile, most have been used for respiration experiments. Only individuals of Monosyn . nga longispina and some little hexactinellid sponges will be carried back to Bremerhaven. Respiration experiments were carried out with unfiltered sea water in a closed but intermittently opened (whenever oxygen saturation was below 80-85%) system. Oxygen saturation in the water was determined by micro optodes (Holst et al., 1997). Constant mixing in the respiration chambers was assured using peristaltic pumps which pumped the water from the chambers to the measuring optodes and back to the chambers. An additional empty chamber (i. e. containing water but no animal) was used in every run to compensate for bacterial respiration. During this cruise ten respiration experiments, lasting for two to three days each, were carried out. Nine individuals of Cinachyra Antarctica, 14 individuals of Stylocordyla borealis, and four little specimens of hexactinellid sponges were measured. For these sponges only dripping wet weight (ww) has been determined on board. Specimens were frozen for later determination of dry weight and ash free dry weight. To support findings of the respiration experiments the analysis of ETS was carried out with newly caught sponges and those taken from the aquaria. As ETS is based on enzyme activity and as it takes some time to assimilate or decompose enzymes, there is little or no change in ETS levels to be expected within the first hours after a catch. ETS measurements will give an estimate of maximum capacities of oxygen consumption and changes that are caused by taking sponges from their natural habitat to aquaria. It should thus be possible to assess whether or not respiration rates measured on board are a good estimate of in-situ respiration rates. Silicate uptake- Prior to freezing, sponges coming from respiration experiments were transferred into silicate- uptake experiments. For these nalgene bottles were filled with 750 ml of filtered sea water and an additional supply of liquid food (4-5 drops of Liquifry per 10 1 water). As silicate uptake is an energy consuming process food limitation could limit silicate-uptake rates even when silica is present in excess. Constant bubbling with air supplied oxygen and assured mixing within the bottles. Again a control was run (nalgene bottle without an animal). Silicate levels in the water were monitored by taking 20-ml samples every six to ten hours. Analyses followed the Koreleff method described by Grasshof et al (1983). Dissolution experiments with spicule mats and dead sponges will be carried out in the AWL Preliminary results All specimens examined tolerated being transferred from the aquarium to a respiration chamber and later to a nalgene bottle for silicate-uptake experiments apparently without problems. After an initial phase of slight construction of the oscula all sponges opened their oscula (exhalant openings), thus showing active water transport through their systems. It was possible to cover a good size range for both species. Individuals of Stylocordyla borealis and Cinachyra Antarctica varied between 2 to 75g and 1.5 to 64g of ww, respectively. From the oxygen and silicate decrease in the water respiration rates and silicate uptake rates will be calculated once dry weight and ash free dry weight have been determined at the AWL REFERENCES Barthel D. (1995): "Tissue composition of sponges from the Weddell Sea, Antarctica'. not much meat to the bones" in Mar. Ecol. Prog. Ser. Vol 123 pp 149-153 Grasshof K. et al. (1983)- "Methods of seawater analysis" Weinheim, Chemie Verlag, 419p Hoist G. et al. (1997)- "A microoptode array for fine-scale measurement of oxygen distribution" in Sensors and Actuators B Vol. 38-39 pp 122-129. 5. ACKNOWLEDGEMENTS The achievements during the leg were to are large extent due to the effective and heartfelt cooperation between the ship's crew and the participating scientific personal. We are grateful to the Master Keil and his crew 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. ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 6. PARTICIPATING INSTITUTIONS ADDRESS PARTICIPANTS LEG ------------------------------- ------------ --- BRAZIL FURG Department of Physics 2 4 University of Rio Grande Rio Grande RS CEP 96201-900 FEDERAL REPUBLIC OF GERMANY AWI Alfred-Wegener-Institut für 12 4 Polar- und Meeresforschung Columbusstraße D-27568 Bremerhaven DWD Deutscher Wetterdienst 2 4 Seewetteramt Postfach 301190 D-20304 Hamburg HSW Helicopter-Service 3 4 Wasserthal GmbH Kätnerweg 43 D-22393 Hamburg UFT Zentrum für Umweltforschung 1 4 und Technologie (UFT) Abt. Marine Mikrobiologie Universität Bremen Postfach 330 440 D-28334 Bremen IUPT IUP - Institut für Umweitphysik 6 4 Abt. Tracer-Ozeanographie Universität Bremen, FB 1 Postfach 330 440 D-28334 Bremen IUPF IUP - Institut für Umweltphysik 1 4 Abt. Fernerkundung Universität Bremen, FB 1 Postfach 330 440 D-28334 Bremen ADDRESS PARTICIPANTS LEG ------------------------------- ------------ --- THE NETHERLANDS NIOZ Netherlands Institute 1 4 for Sea Research P.O. Box 59 1790 Ab den Burg Texel NORWAY IM Institutt for Mikrobiologi 1 4 Jahnebakken 7 N-5020 Bergen SPAIN 1CM Instituto de Ciencias del Mar 1 4 Paseo Juan De Boron S/N 08039 Barcelona LEM Laboratori d'Engiyeria Maritima 4 Universtat Politecnica de Catalunya C/Gran Capita s/n, Modul D-1 08034 Barcelona RUSSIA AAI Andreyev Acoustics Institute 1 4 Shvernika 4 117034 Moscow UNITED KINGDOM PML Plymouth Marine Laboratory 1 4 West Hoe, Plymouth Devon, PL1 3DH ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 7. CRUISE PARTICIPANTS NAME INSTITUTION ------------------------- --------------------- Bakker, Karel NIOZ Bellerby, Richard PML Bulsiewicz, Klaus IUPT Büchner, Jürgen HSW Fagerbakke, Kjell Magne IM Fahrbach, Eberhard AWI Feldt, Oliver HSW Frenzel, Martin AWI Fraas, Gerhard IUPT Fürhaupter, Karin GEOMAR Gatti, Susanne AWI Harms, Sabine AWI Härter, F.F. Antonio FURG Hartig, Rüdiger DWD Heeschen, Katja GEOMAR Heuchert, Anja UFT Hoppema, Mario IUPT Huhn, Olliver IUPT laremtchouk, Alexei AAI Klatt, Olaf IUPT Köhler, Herbert DWID Krause, Peter HSW Langreder, Jens AWIAUPT Meissner, Katrin AWI Mir Casanovas, Carlos ICM/LEM Monsees, Matthias AWI/IUPT Pereira Ferreira, Adriene AWI/FURG Rodehacke, Christian IUPT Rohardt, Gerd AWI Schlüter, Norbert IUPF Schodlok, Michael AWI Schröder, Michael AWI Schuster, Fritz AWI (ab Neumayer Station) Wisotzki, Andreas AWI Witte, Hannelore AWI 8. SHIP'S CREW POSITION NAME ------------------------- --------------------- Kapitän Keil, Jürgen 1. nautischer Offizier Schwarze, Stefan Leitender techn. Offizier Schulz, Volker 2. nautischer Offizier Block, Michael 2. nautischer Offizier Malz, Ingo 2. nautischer Offizier Peine, Lutz Arzt Bennemann, Jürgen Funkoff izier Hecht, Andreas 2. technischer Offizier Delff, Wolfgang 2. technischer Offizier Folta, Henryk 2. technischer Offizier Simon, Wolfgang Elektroniker Dimmler, Werner Elektroniker Fröb, Martin Elektriker Holtz, Hartmut Elektroniker Pabst, Helmar Elektroniker Piskorzynski, Andreas Schiffbetriebsmeister Loidl, Reiner Zimmermann Neisner, Winfried Facharbeiter/Deck B&cker, Andreas Facharbeiter/Deck Bindernagel, Knuth Facharbeiter/Deck Bohne, Jens Facharbeiter/Deck Hagemann, Manfred Facharbeiter/Deck Hartwig, Anderas Facharbeiter/Deck Moser, Siegfried Facharbeiter/Deck Schmidt, Uwe Facharbeiter/Deck Winckler, Michael Storekeeper Beth, Detlef Facharbeiter/Maschine Arias Iglesias, Enr. Facharbeiter/Maschine Dinse, Horst Facharbeiter/Maschine Fritz, Günter Facharbeiter/Maschin Giermann, Frank Facharbeiter/Maschine Krüsche, Eckard Koch Silinski, Frank Kochsmaat Beck, Walter Kochsmaat Tupy, Mario 1. Stewardess Dinse, Petra 1. Stewardess Wöckener, Martina 2. Stewardess Klemet, Regine 2. Stewardess Schmidt, Maria 2. Stewardess Silinski, Carmen 2. Steward Tu, Jian-Min 2. Steward Wu, Chi Lung Wäscher Yu, Chung Leung ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 APPENDIX 1, MOORINGS TABLE 1: MOORINGS RECOVERED IN THE WESTERN WEDDELL SEA. Record Latitude Date Water Length Mooring Longitude Time (UTC) Depth (m) Type SN Depth (m) (Days) -------- ---------- --------- -------- ------ ------- -------- ------ AW1216-2 63° 57.6'S 06.05.96 3520 AVTP 11926 262 699 49° 08.8'W 18.00 ACM-CTD 1403 573 (1) AVT 11885 2549 699 AVT 11886 3474 699 Sc 631 3475 699 (2) AW1207-4 63° 43.3'S 07.05.96 2510 ULS 08 174 (3) 50° 49.2'W 22:00 AVTPC 9207 270 695 TC250 2299 505 (5) 695 ACM-CTD 1402 762 464 (4) AV7 9767 2187 695 TC250 2371 2198 (5) 695 AVT 9206 2454 695 Sc 1979 2455 695 (2) AW1206-4 63° 29.6'S 08.05.96 952 ULS 09 150 (3) 52° 06.1'W 20:00 AVTP 11890 246 693 ACM-CTD 1409 491 463 (6) AVT 9401 906 (7) SC 1977 907 693 (2) AW1215-3 63° 19.6'S 09.05.96 465 AVTP 11892 259 692 52° 46.9'W 00:00 AVT 9402 459 692 Sc 1974 460 692 (2) WLR 1154 465 692 AW1234-1 62° 51.4'S 09.05.96 284 ADCP 378 275 (3) 53° 40.3'W 17:00 Sc 1975 280 691 Remarks: 1: found water inside - memory destroyed 2: found intense marine growth - destroyed conductivity measurements 3: data not processed but could retrieve complete memory contents 4: instruments stopped recording on August 1997 5: upper level of 11 temperature sensors with 25m spacing 6: only CTD recorded until August 1997 7: no data recorded Table 2: Moorings deployed in the western Weddell Sea. Latitude Date Water Mooring Longitude Time (UTC) Depth (m) Type SN Depth (m) -------- ---------- --------- -------- ------ ------- -------- AW1215-4 63° 19.6'S 01.04.98 450 AVT 10496 445 52° 47.1'W 22:25 WLR 1716 450 AW1206-5 63° 30.4'S 02.04.98 965 AVTP 11889 250 52° 06.7'W 21:20 AVTPC 12462 500 AVT 10499 921 AW1207-5 63° 42.8'S 04.04.98 2500 AVTPC 209 262 50° 52.1'W 15:44 ACT 100 85 647 ACT100 86 748 AVTPC 12463 752 AVTPC 12443 2179 TC100 2486 2340 TC100 2485 2440 AVTPC 12451 2445 MIR II 60° 34.5'S 19.04.98 1637 AVTPC 12452 677 49° 30.8'W 20:46 AVTPC 12454 1593 XM1A 60° 28.3'S 18.04.98 1713 VACM 1950b49 1663 48° 27.0'W 16:05 ARGOS 14961 XM1B 60° 28. VS 18.04.98 1713 VACM-P 1951855 1208 48° 27.2V 15:56 ARGOS 14957 XM2A 60" 28.5'S 18.04.98 1615 VACM 2218b0f 1565 47° 58.2'W 20:07 ARGOS 9371 XM2B 60° 28.3'S 18.04.98 1547 VACM-P 2217004 1042 47° 58.6'W 19:52 ARGOS 14958 XM3A 60° 38.2'S 19.04.98 1413 VACM 221fe5e 1565 49° 52.3'W 17:34 ARGOS 14959 XM3B 60° 38.2'S 19.04.98 1414 VACM-P 221fdd8 909 49° 52.3'W 17:29 ARGOS 14956 ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 TABLE 3: MOORINGS RECOVERED AT THE GREENWICH MERIDIAN. Record Latitude Date Water Length Mooring Longitude Time (UTC) Depth (m) Type SN Depth (m) (Days) -------- ---------- --------- -------- ------ ------- -------- ------ AW1233-2 69°24.2'S 16.02.97 1985 ULS 34 139 (1) 00°00.0'W 20:00 AVTP 10539 236 436 AVT 6856 736 436 ACM-CTD 1449A 1941 436 AW1232-2 69°00.0'S 17.02.97 3409 ULS 35 191 (2) 00°00.0'W 04:00 AVTP 10004 297 437 ACTP 9785 803 437 AVT 10503 2009 437 ACM-CTD 1454A 3366 437 AW1231-1 66°30.O'S 20.04.96 4520 ULS 26 170 (1) 00°00.4'W 14:00 AVTPC 9213 219 741 SC 1976 220 (3) TC250 1104 236 741 (4) TC250 1256 512 741 AVTP 9212 788 741 SC 630 789 741 (5) AVT 9561 1815 741 (6) ACM-CTD 1390A 4476 121 (7) AW1230-1 66°00.2'S 19.04.96 3450 ULS 25 51 (1) 00°09.5'E 18:00 AVTPC 9765 91 744 SC 1166 92 (3) TC250 1102 123 744 (8) TC250 1103 399 744 (9) AVTPC 9215 664 (10) SC 1167 665 744 AVT 10498 1671 744 ACM-CTD 1411A 3406 555 (7) AW1229-1 63°59.6'S 18.04.96 5186 ULS 07 165 (1) 00°00.30'W 14:00 AVTP 11888 215 746 SC 1973 216 (3) TC250 943 240 746 TC250 1100 515 746 AVTPC 9786 784 746 SC 319 785 746 AVT 9770 2011 746 ACM-CTD 1400A 5142 589 (7) AW1227-4 59°03.7'S 10.01.97 4660 ULS 37 135 (1) 00°02.7'E 04:00 AVTPC 10872 246 483 ST 477 (11) ACM-CTD 1448A 684 483 AVT 9183 1990 483 ST 3366 (11) AW1228-1 57°00.0'S 13.04.96 3872 ACM-CTD 1452A 4615 483 00°00.2'E 18:00 AVTP 11887 449 545 (12) ACM-CTD 1389A 810 717 (7) AVT 9768 2105 759 ACM-CTD 1387A 3827 759 REMARKS: 1: data not processed but could retrieve complete memory contents 2: instrument was lost 3: instrument must be returned to the manufacturer to retrieve data from memory 4: sensors 4 to 8 failed 5: temperature sensor failed 6: rotor lost; no speed record 7: incomplete time series due to old firmware, and battery failures 8: sensors 1 to 11 failed 9: all sensors failed during the second period of the time series 10: instrument destroyed due to blown up batteries 11: no obvious problems found 12: no complete time series due to empty batteries ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 TABLE 4: MOORINGS DEPLOYED AT THE GREENWICH MERIDIAN. Latitude Date Water Mooring Longitude Time (UTC) Depth (m) Type SN Depth (m) -------- ---------- --------- -------- ------ ------- -------- AW1233-3 69°23.9'S 29.04.98 2057 ULS 36 155 00°00.7'W 19:57 AVTP 9763 248 AVTPC 9783 749 ACM-CTD 1453A 1954 AW1232-3 68°59.7'S 30.04.98 3375 ULS 39 148 00°03.7'W 16:56 AVTPC 9201 246 AVTPC 10492 752 AVTPC 9214 1798 ACM-CTD 1385A 3304 AW1231-2 66°30.0'S 02.05.98 4520 ULS 42 151 00°01.1'W AVTPC 9200 187 CT500 ACM-CTD 1386A 698 AVT 9391 1804 ACM-CTD 1443A 4465 AW1229-2 63°58.5'S 05.05.98 5180 ULS 43 150 00°04.6'E 18:51 AVTP 10002 196 CT500 ACM-CTD 1391A 707 AVT 9186 2003 ACM-CTD 1392A 5134 AW1227-5 59°04.2'S 08.05.98 4660 ULS 40 144 00°04.9'E 14:40 AVTP 10541 254 AVTPC 9211 692 SM37P 244 693 AVT 9190 1998 ACM-CTD 1388A 4555 AW1228-2 56°58.6'S 13.05.98 3710 AVTPC 8418 241 00°01.3'E 14:40 AVTP 8417 447 AVT 9179 803 SM37P 245 804 AVT 9180 2005 ACM-CTD 1404A 3655 ABBREVIATIONS: ACM-CTD Falmouth Scientific 3-dimension acoustic current meter with CTD-sensor head (CTD=Conductivity, Temperature, Depth) ACT 100 Aanderaa temperature/conductivity sensor string, 100 m length, 5 sensor pairs ADCP RD[ Inc. Acoustic Doppler Current Profiler AVTPC Aanderaa current meter with temperature, pressure, and conductivity sensors AVTP Aanderaa current meter with temperature and pressure sensors AVT Aanderaa current meter with temperature sensors CT500 10 ea. SeaBird Electronics MicroCat CT Recorder attached at 500m mooring rope SC SeaBird Electronics self contained CTD, type: SeaCat SM37 SeaBird Electronics MicroCat CT Recorder SM37P SeaBird Electronics MicroCat CT Recorder with 3000 psi pressure sensor ST Sediment trap TC100 Aanderaa thermistor cable, 100 m length, 11 sensors, 10 m spacing TC250 Aanderaa thermistor cable, 250 m length, 11 sensors 25 m spacing ULS Upward Looking Sonar Christian Michelsen Research Inc. VACM Oregon Environmental Instruments vector averaging current meter with temperature sensor; automatic release and ARGOS data transmission VACM-P Oregon Environmental Instruments vector averaging current meter with temperature sensor and pressure; automatic release and ARGOS data transmission ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 APPENDIX 2, STATION LIST (SEE SUM FILE) APPENDIX 3, XBT DATA Failed Depth No. Date Time(GMT) Latitude Longitude (m) --- -------- -------- --------- --------- ----- 000 30.03.98 05:12 55°03.0'S 64°55.0'W 1000 001 06:07 55°13.0'S 64°43.2'W 1504 002 07:06 55°23.0'S 64°30.9'W 4757 003 08:05 55°32.9'S 64°19.7'W 3721 004 09:05 55°43.0'S 64°07.3'W 3721 005 10:05 55°52.5'S 63°55.3'W 3721 006 11:12 56°03.0'S 63°41.5'W 3721 007 12:10 56°13.0'S 63°29.0'W 4054 008 13:24 56°22.9'S 63°16.4'W 3965 009 14:30 56°33.0'S 63°03.1'W 4012 010 15:37 56°43.0'S 62°51.3'W 4084 011 16:45 56°53.0'S 62°38.1'W 4066 012 17:51 57°03.0'S 62°24.0'W 3915 013 18:56 57°13.0'S 62°10.5'W 3916 014 19:57 57°22.9'S 61°58.0'W 3929 015 20:59 57°33.0'S 61°44.7'W 3327 016 21:59 57°43.2'S 61°30.7'W 3760 017 22:56 57°53.1'S 61°17.6'W 3462 018 23:52 58°03.0'S 61°04.3'W 2882 019 31.03.98 00:52 58°13.1'S 60°50.5'W 3472 020 01:51 58°23.0'S 60°37.7'W 3621 021 02:51 58°33.0'S 60°24.6'W 3417 022 03:51 58°43.0'S 60°12.0'W 3835 023 04:51 58°53.0'S 59°57.6'W 3734 024 05:55 59°03.0'S 59°43.1'W 2916 025 06:59 59°13.0'S 59°29.7'W 3606 026 07:56 59°23.1'S 59°17.0'W 3123 027 09:01 59°33.0'S 58°04.9'W 3064 028 10:20 59°42.9'S 58°50.1'W 2426 029 11:40 59°53.0'S 58°34.7'W 1976 030 12:59 60°03.0'S 58°19.8'W 1831 031 14:13 60°13.0'S 58°06.5'W 3530 032 15:24 60°23.0'S 57°52.4'W 3740 033 f 16:36 60°33.0'S 57°38.0'W 4010 034 16:44 60°34.0'S 57°36.4'W 4150 035 19:37 60°38.9'S 57°32.1'W 4223 036 20:51 60°48.9'S 57°15.4'W 4676 037 22:08 60°58.9'S 57°00.0'W 2954 038 23:16 61°09.0'S 56°44.5'W 1912 Failed Depth No. Date Time(GMT) Latitude Longitude (m) --- -------- -------- --------- --------- ----- 039 01.04.98 00:25 61°19.0'S 56°29.0'W 4370 040 01:30 61°29.0'S 56°15.9'W 578 041 02:36 61°39.1'S 56°01.4'W 727 042 03:44 61°49.0'S 55°43.3'W 2630 043 04:59 61°59.0'S 55°22.6'W 1235 044 06:07 62°09.0'S 55°03.8'W 2750 045 07:22 62°19.1'S 54°45.0'W 3854 046 08:35 62°29.0'S 54°32.8'W 3377 047 09:50 62°38.9'S 54°03.8'W 3587 048 24.04.98 08:00 62°28.0'S 36°37.8'W 3904 049 10:00 62°38.5'S 35°56.6'W 5003 050 12:00 62°50.0'S 35°19.6'W 4813 051 14:00 63°02.1'S 34°38.9'W 4796 052 16:00 63°13.5'S 33°51.8'W 4870 053 18:00 63°24.6'S 33°02.4'W 4954 054 20:00 63°35.9'S 32°12.8'W 4545 055 22:00 63°47.6'S 31°29.9'W 4013 056 25.04.98 00:00 64°01.2'S 30°39.8'W 4888 057 02:00 64°13.4'S 29°49.7'W 4804 058 04:00 64°23.8'S 28°57.1'W 4951 059 06:00 64°33.4'S 28°05.0'W 4464 060 08:00 64°43.2'S 27°15.2'W 4754 061 10:00 64°53.3'S 26°28.6'W 4891 062 12:00 65°04.1'S 25°39.7'W 4704 063 14:00 65°14.8'S 24°51.0'W 4957 064 16:00 65°24.6'S 24°00.5'W 4964 065 18:00 65°34.9'S 23°09.8'W 4965 066 26.04.98 00:00 65°44.5'S 22°16.8'W 4969 067 13.05.98 15:41 56°59.3'S 00°01.1'W 3924 068 16:38 56°50.9'S 00°00.9'W 3975 069 17:35 56°41.5'S 00°00.0'W 4501 070 21:50 56°30.2'S 00°00.2'W 4090 071 22:50 56°20.9'S 00°00.0'W 3734 072 23:50 56°10.9'S 00°00.0'W 4168 073 14.05.98 03:30 55°59.2'S 00°01.2'W 3713 074 04:30 55°48.7'S 00°00.5'W 4069 075 05:30 55°38.9'S 00°00.0'W 3668 076 06:30 55°30.8'S 00°00.1'W 3774 077 09:40 55°31.4'S 00°01.8'E 3860 Failed Depth No. Date Time(GMT) Latitude Longitude (m) --- -------- -------- --------- --------- ----- 078 10:40 55°22.0'S 00°02.9'E 2899 079 11:40 55°09.8'S 00°01.2'E 3412 080 14:12 55°00.2'S 00°00.5'W 1750 081 15:11 54°48.9'S 00°00.7'W 1218 082 16:12 54°36.8'S 00°00.0'W 1092 083 18:22 54°29.5'S 00°00.6'W 1756 084 19:22 54°17.7'S 00°00.6'W 2584 085 20:22 54°06.2'S 00°00.3'W 2682 086 21:22 54°00.0'S 00°00.3'W 2459 087 22:58 53°59.8'S 00°00.6'W 2417 088 23:57 53°48.9'S 00°00.0'W 2673 089 15.05.98 00:59 53°37.0'S 00°00.5'E 2803 090 01:55 53°26.8'S 00°00.4'E 2550 091 02:54 53°16.1'S 00°00.6'W 2163 092 03:55 53°04.9'S 00°00.6'W 1836 093 06:35 53°00.9'S 00°00.2'E 2550 094 07:35 52°51.7'S 00°01.0'E 2670 095 08:35 52°41.2'S 00°00.4'E 2742 096 09:35 52°31.5'S 00°00.1'E 2650 097 10:35 52°22.6'S 00°00.1'W 2627 098 11:35 52°13.0'S 00°00.0'E 3148 099 18:45 52°01.6'S 00°02.3'W 3050 100 16.05.98 07:05 51°00.0'S 00°00.7'E 2359 101 08:05 50°51.1'S 00°00.4'E 2226 102 09:05 50°41.2'S 00°00.1'W 1541 103 10:05 50°31.4'S 00°00.1'E 3535 104 11:05 50°21.3'S 00°00.7'E 3653 105 12:03 50°10.8'S 00°00.3'E 3567 106 15:48 50°00.1'S 00°04.3'E 3452 107 16:48 49°50.0'S 00°04.7'E 3750 108 17:48 49°39.2'S 00°03.6'E 3965 109 18:48 49°28.6'S 00°02.2'E 4128 110 19:48 49°17.3'S 00°00.8'E 3180 111 20:48 49°06.2'S 00°00.3'E 3842 112 17.05.98 00:20 49°00.1'S 00°00.2'E 3970 113 01:19 48°50.8'S 00°00.2'E 3938 114 02:18 48°39.7'S 00°00.8'W 3863 115 03:19 48°28.3'S 00°00.3'W 3574 116 04:19 48°17.0'S 00°00.3'E 3246 Failed Depth No. Date Time(GMT) Latitude Longitude (m) --- -------- -------- --------- --------- ----- 117 05:20 48°05.2'S 00°00.4'W 3960 118 08:55 48°00.5'S 00°00.4'E 3922 119 09:55 47°50.5'S 00°05.0'E 3928 120 10:55 47°39.1'S 00°11.7'E 3868 121 11:55 47°28.0'S 00°17.9'E 3826 122 12:55 47°16.1'S 00°24.3'E 4191 123 16:50 47°03.0'S 00°29.7'E 3810 124 17:50 46°53.3'S 00°35.2'E 3370 125 18:50 46°42.3'S 00°42.2'E 4100 126 19:50 46°31.5'S 00°48.6'E 4100 127 20:50 46°20.9'S 00°54.5'E 4459 128 21:50 46°09.5'S 01°00.8'E 3776 129 18.05.98 01:14 46°08.9'S 01°04.9'E 4173 130 02:13 45°58.3'S 01°09.4'E 4456 131 03:12 45°46.9'S 01°13.6'E 4363 132 04:13 45°35.7'S 01°18.6'E 4475 133 05:13 45°24.3'S 01°24.3'E 4180 134 09:35 45°11.7'S 01°30.8'E 4226 135 10:35 45°02.0'S 01°35.5'E 3040 136 11:35 44°50.0'S 01°42.5'E 3777 137 12:33 44°39.2'S 01°48.7'E 4780 138 13:35 44°27.9'S 01°54.7'E 4672 139 14:36 44°16.4'S 02°00.5'E 4437 140 17:50 44°15.3'S 02°00.9'E 4444 141 18:50 44°05.6'S 02°05.8'E 4430 142 19:50 43°55.1'S 02°11.1'E 4633 143 20:50 43°43.6'S 02°17.7'E 4553 144 21:50 43°30.9'S 02°23.8'E 4435 145 22:50 43°20.3'S 02°29.3'E 4444 146 19.05.98 01:22 43°19.0'S 02°31.3'E 4481 147 02:21 43°12.6'S 02°44.7'E 4465 148 03:21 43°05.2'S 02°59.0'E 4460 ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 DATA PROCESSING NOTES DATE CONTACT DATA TYPE DATA STATUS SUMMARY -------- ----------- ------------- ---------------------------------- 07/25/01 Witte CTD/BTL/SUM Submitted The directory this information has been stored in is: 20010725.005322_WITTE_SR4 The format type is: ASCII The data type is: Sumfile BottleFile CTDFile DOCFile The Bottle File has the following parameters: CTDPRES,CTDTMP,CTDSAL,SALNTY,OXYGEN,SILCAT,NITRAT,NITRIT,PHS, PHT The Bottle File contains: CastNumber StationNumber BottleNumber WITTE, HANNELORE would like the data PUBLIC. And would like the following done to the data: place data on-line 12/04/01 Diggs CTD/BTL/SUM Website Update; Data OnLine New cruise! Submitted by Hannalore Witte on 7/25/2001. Data are in sr04_e/original. Need information, i.e. who is the PI? I just found a cruise that apparently has been languishing in the INCOMING area for a while, since last July 25,2001. Hannalore Witte went through the proper procedures and submitted them using the old webform. I have hand-edited the woce_lines.txt file and added it to the RCSable lines. It's been RCS'd, and resides in the data area under sr04_e/original The CTD files are 'close' to WOCE format, the bottle file seems dead-on, and the SUMfile is way off. 12/19/01 Hajrasuliha STATRK station track made Images created for the station track map. .JPG and .GIF 12/19/01 Bartolacci CTD/BTL/SUM Reformatted data online I have created an idex page for these data, reformatted all files and placed all files online. Correspondence will need to be initiated with the data PI Hannelore Witte in order to solve minor format and parameter questions, however all files are in WOCE format. All original files reside in the original directory, a station track map still needs to be generated for this cruise. 2001.12.17 DMB Reformatting notes for SR04_e 06AQANTXV_4. Data sent by Hannelor Witte in July, 2001. SUM: 1. Added Following parameter columns to file: EXPOCODE-06AQANTXV_4 WOCE SECT-SR04 2. CAST TYPE-added CTD, because original sumfile header indicated file was a list of CTD stations for this cruise, however since bottle data do exist, stations in the sumfile that contain bottle data should get ROS instead of CTD. This is a minor point however (as per J. Swift) and does not ffect the formatting of the file. 3. CODE- added UN, since no cast codes were given and only one line per cast exists. 4. NAV- added UNK, since no nav information was given. 5. Removed following columns, *note these should be confirmed with data PI as to relevance: SN- this column was had a value of 1360 throughout the entire file. possibly some serial number? As per J. Swift this column can remain deleted from WHP file. Confirm what WAT. DEPTH is. Currently WAT. was removed from the DEPTH header. As per J. Swift, WAT (water) depth can be removed from header. 6. Realigned all columns to adhere to woce format. 7. changed DATE from 03 31 1998 (mmddyyyy) format to 033198 (mmddyy) format. 8. changed UTC time from hhmm format to hhmm format. 9. Added hemisphere character designator and removed all negative signs in latitudes and longitudes. 10. Added ship name cruise name and leg designator to first header line. 11. Added name/date stamp. 12. Ran sumchk with no errors. 13. Renamed file sr04_esu.txt BOT: 1. Edited parameter header line to proper WOCE alignment. 2. changed expocode 06AQANTXV/4 to 06AQANTXV_4. 3. Added name/date stamp. 4. Ran wocecvt with no errors. Several pressure inversions and duplicate depths do exist. 5. Renamed file sr04_ehy.txt CTD: 1. Changed expocode 06AQANTXV/4 to 06AQANTXV_4 in all station files. 2. ran wctcvt with no errors, however TRANSMS header is unrecognized by diagnostic code. Format passed diagnostic code. 3. zipped up files remaning zip file to sr04_ect.zip ____________________________________________________________________________________________ ____________________________________________________________________________________________ SR04 • Fahrbach • RV/Polarstern • 1998 DATE CONTACT DATA TYPE DATA STATUS SUMMARY -------- ----------- ------------- ---------------------------------- 03/04/02 Uribe CTD/BTL Website Updated: Exchange file online CTD and bottle have been converted to exchange and put online. Data was checked in JOA and no apparent problems were noticeable. 01/10/05 Key TCARBN Data Question: some lat/long values wrong? This is just a guess at this point based on a file I recently received from Mario Hoppema (PI for the tco2) for this cruise. It appears that both the WHPO SUM and exchange files have errors in the longitudes for stations which fall along the main S-N transect at the end of the cruise. I've attached a figure which shows the difference. I don't know for sure which is correct, but the ship probably went into Capetown which would favor the Hoppema file. Whichever is correct, it's just a sign change (or W to E) for the ones that are wrong. I'd appreciate a note if my guess is wrong and the WHPO locations are indeed correct. The Hoppema file also has about twice the number of bottle records as the one at WHPO. I haven't yet figured this out, but will keep you posted. 01/10/05 Key TCARBN Data Update: Key has public data I have recently been in contact with Mario Hoppema regarding data from this cruise. He sent me a new data file which contains TCO2 measurements which he now considers "public". He also believes that his data were submitted to WHPO quite awhile back. There is also the possibility that Roether has submitted his CFC and perhaps H3/He3 results from this cruise. Before I bother Wolfgang, could you see if you have anything which is not on-line. If you don't have the TCO2, I'll send it as soon as I've merged the values. If you don't have the CFC and/or H3/He3 let me know and I'll get in touch with Wolfgang. Since Wolfgang is now retired, we need to bump priority on these data before they're lost. DATE CONTACT DATA TYPE DATA STATUS SUMMARY -------- ----------- ------------- ---------------------------------- 01/11/05 Anderson SUM Website Updated: corrected longs. Corrected some of the longitude hemisphere indicators from W to E. Checked original .SUM file sent by H. Witte which also indicated that the stations in question should be E not W. 01/13/05 Anderson CTD Data Update: corrected longs. Made new exchange file for the ctd's to reflect the changes made to the longitudes in the .sum file on Jan. 11, 2005. A new NETCDF file and corrected station position map need to be generated. 01/31/05 Roether BTL/SUM Submitted new sum file & tracers CTDPRS, CTDTMP, CTDSAL, OXYGEN, SILICAT, NITRAT, NITRIT, PHSPHT, CFC-11, CFC-12, CFC113, CCL4, TRITUM, HELIUM, DELHE3, NEON, O18/O16, TCARBN, ALKALI, FCO2, PH Dear Bob (Key), Here are the tracer data that you asked for. Specifically: The first file is an ASCII table with all the bottle data of the cruise, as explained on p. 1 of the second file. I also enclose our station data for the cruise (Lat/long/water depth/date) , which might solve your problem with incoherent station information. If however the discrepancy remains unsolved, you should adress Mario because ANT 15-4 was an AWI cruise so they must have the real information. Comment: All our tracer data should have been submitted to WHPO, but the above file is the best info there is. Flags are according to WOCE requirements. There are two flag-words of 12 digits each at the end of each sample line (see table on p. 1 of the seond file what the individual flags refer to). The table includes errors for tritium and the helium/neon species, but not for the CFCs. Their errors are as follows: CFC-11, CFC-12 < 1% (all data) CFC-113 < 1.5 to 2% or O.002pmol/kg, whichever is greater CCl4 < 2.5% , but additional uncertainty of +- 0.18 pmol (or less) for Stas. 3-6. Part of the helium samples were taken in a non-traditional way (sucking water into an evacuated ampoule), such data are denoted by a 7 as the last digit in the second flag word (regular copper samples have an 8 at that position). Intercalibrations have been made, and the errors given in the big table account for that. Part of the vaccuum samples had some air contamination, if small enough a correction was made using the neon value, in which case no neon value is given in the table. 02/15/05 Anderson CFCs/HeTr/CO2 Update Needed: requested data from Key I don't see any of that data here. Send it along and I will merge it this week. DATE CONTACT DATA TYPE DATA STATUS SUMMARY -------- ----------- ------------- ---------------------------------- 02/16/05 Key CFCs/HeTr/CO2 Submitted The new data for this cruise are attached. I only included what you don't have. As usual, my software doesn't worry about number of decimal places and truncates trailing decimal zeros. The flags are as assigned by the data generators (Roether, Hoppema and perhaps others) and follow WOCE convention. tracer"e" are errors and tracer"f" are flags. The header is not WOCE, but I don't think you'll have any problem. You should get a 1 to 1 match to the hydro file. I did a quick check and these appear to be first class data. 02/18/05 Anderson CFCs/HeTr/CO2 Website Updated: Data Online Merged the TCO2, CFC-11, CFC-12, CFC113, CCL4, TRITUM, TRITER, HELIUM, HELIER, DELHE3, DELHER, NEON, and NEONER into the online file. Data were submitted by Bob Key on Feb. 16, 2005. There were no apparent problems. 04/14/05 Witte Cruise Report Submitted summary as attachment I send you the summery of the cruise report of ANTXV/4. The whole cruise report is only a hard copy. If you want it also, please let me know. 04/26/05 Witte Cruise Report Submitted Hard Copy Report is German and English. will need to be scanned and converted to text and PDF files. 05/20/05 Kappa STATRK Data Update: Station Track incorrect I noticed that our station plot for sr04_e has an error in it. I've attached a pdf showing approximately how it should look: the northernmost leg should curve east, not west. This may mean the the values in the .sum file are incorrect, too. Can one of you fix this and send me a ps. file of the new station track? 05/23/05 Diggs STATRK Website Updated: new sta. track online Updated Map on website from entries in new SUMFILE corrected by S. Anderson. DATE CONTACT DATA TYPE DATA STATUS SUMMARY -------- ----------- ------------- ---------------------------------- 05/26/05 Kappa STATRK Data Update: made new station track I hand corrected the old station track to include with the cruise report. It contains the 6 stations missing from Steve's recently generated station track. A pdf of my new statrk is attached. 05/26/05 Key CFCs/HeTr/CO2 Data Update: Key has new data files The bottle data file available on-line for this cruise just has T,S.O2,nuts. I have been in contact with Mario Hoppema, Wolfgang Roether and Birgit Kline. With their help, I now have values (and flags) for: CFC-11,12,113, CCl4 H3,He3,He-4 (with errors) Neon (with errors) TCO2 Roether says that he had previously submitted the data to WHPO and that it just hadn't been posted. Regardless, let me know what you don't have and I'll send it along. I'm still trying to verify responsible PIs for the new values. Documentation for this cruise says that C13 was collected, but I haven't been able to dig anything up on this. 05/27/05 Kappa Cruise Report Assembled new pdf and text reports Previous online report was only CTD calibrations. New report, from hard copy submitted by H. Witte, contains: a cruise narrative, reports on tracers, atmosphere investigations, and marine biology. Also includes figures, tables, and these data processing notes. PDF and Text versions made.