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Arctic deep-sea research: the Nansen Basin Section
Deep-SeaResearch,Vol. 39, Suppl. 2, pp. $419--$423,1992. Printedin GreatBritain.
0198--0149/92$5.00+ 0.00 ~) 1992PergamonPressLtd
Introduction Arctic deep-sea research: the Nansen Basin Section STEPHANIE L. PFIRMAN* a n d Jt)RN THIEDE?
(Received 26 March 1992; in revised form 30 March 1992; accepted 30 March 1992)
The papers of this special issue of Deep-Sea Research concern the Arctic Ocean, an area that was inaccessible to full-scale oceanographic investigations until the recent advent of research icebreakers. During the summer of 1987, a multi-disciplinary and international team of investigators aboard the German R.V. Polarstern penetrated the Arctic pack ice as far north as the Gakkel Ridge in the central eastern Arctic basin (Fig. 1). At 86°11'N, R.V. Polarstern attained its northernmost position. Although Soviet nuclear-powered icebreakers had previously reached further north to the North Pole, their expeditions were not designed to conduct systematic deep-sea research. As a result, the 1987 expedition obtained the most complete oceanographic transect in the Arctic Ocean since the epic voyage of Fridtjof Nansen with the Fram in 1893-1896, nearly 100 years before. The 1987 expedition began on 4 July, in Troms6, Norway and ended on 2 September 1987 in Hamburg, Germany. Multi-disciplinary investigations were carried out by 55 scientists and technicians representing 20 institutions from seven countries. Investigations included meteorologic, oceanographic, biologic, geologic and sea-ice sampling. The goals were to assess the modern environment, and to determine, through geological investigations, variations in this environment through time. One of the key reasons driving our interest in the Arctic is to understand its relationship to past climate changes in order to predict potential future changes if global warming proceeds as projected. Global climate models predict that warming due to the anthropogenic enhancement of the greenhouse effect will be greatest in the Arctic and subarctic. This not only would have a dramatic impact on the Arctic environment, but also could have significant feedback on global climate through reduction in snow and ice albedos and changes in oceanic circulation. Oceanographic, geologic and biologic information gathered in 1987 represent a major step forward in documenting this complex system. The marine geology and geophysics working group on board R.V. Polarstern was composed of 28 people. Investigations included: 3.5 kHz and seabeam profiling (where ice *Environmental Defense Fund, 257 Park Avenue South, New York, NY 10010, U.S.A. and Lamont-Doherty Geological Observatory of Columbia University, Palisades, NY 10964, U.S.A. ?GEOMAR, Research Center for Marine Geosciences, Wischhofstrasse 1-3, Building 4, D-2300 Kiel 14, Germany. $419
$420
s.L. PFIRMANand J. THIEDE 88* , - ~
~
88*
Arktis LV/5
86*
86*
84*
84*
177.
\
82*
82*
80* 80*
78* 78 °
-L0*
5*
10*
15"
20 °
Fig. 1. Shiptrackof the 1987expeditionwithR.V. Polarstern (ARKIV/3) fromthe BarentsSea to the GakkelRidge, returningthroughFramStraitto the Norwegian-GreenlandSea.
conditions permitted) as well as gravity measurements, heat flow, box coring, piston coring, gravity coring, giant box coring (Kastenlot) and transmissometer profiling. The main objectives of the marine geology and geophysics program were to assess the relative importance of modern sediment sources and to understand the paleoenvironmental and tectonic evolution of the Nansen Basin. First results from the expedition (Polarstern Shipboard Scientific Party, 1988; SPIELHAGENet al., 1988; THIEDEet al., 1988; BAUMANN, 1990; BLEIL and THmDE, 1990; K6HLER and SPIELHAGEN,1990; MIENERT et al., 1990; THIEDE et al., 1990; BOHRMANN,1991; K6HLER, 1991; KUmSCH, 1991; MATTHIESSEN,1991;
Introduction
$421
180"
ALASKA
,NEWII~F o SIBERIAN ISLANDS
'ELIZABETH I ~ ISLANDS
NO.I.SLANOI
P.
~
FRANZ ,IOSEF .*.~ /LAND
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",, POLARSTERN 1987
O*
Fig. 2.
---.....
POLARSTERN 1991 ODEN 199!
o
POLAR STAR 1991
Cruise tracks of the 1987 and 1991 Arctic deep-sea expeditions.
MUEHE et al., 1991; NOWACZYK, 1991; PAGELS, 1991; SPIELHAGEN, 1991) reported that recent sedimentation rates are about 1 cm 1000 y-l, similar to those found in the Norwegian-Greenland Sea but an order of magnitude less than in the central Arctic. Many of the giant box cores were more than 4 m long, composed of silty and sandy clays with minor biogenic components and surprisingly little coarse ice-rafted material. Heat flow was extremely high in the rift valley of the Gakkel Ridge, and a box core from the valley contained fragments of altered basalts (MUEHEet al., 1991). The oceanographic working group comprised 24 researchers. Sampling included conductivity, temperature and depth (CTD) measurements coupled with a 24 bottle rosette water sampler, large volume sampling, expendable bathythermographs, expendable current profilers, and heavy metal sampling. The main goals of the oceanographic program were to understand water mass formation, distribution and renewal rates, including the
$422
s . L . PFIRMANand J. THIEDE
circulation of Atlantic and deep waters and to assess the influence of boundary currents and dense shelf water. Analysis of CTD and tracer data (freons, 14C, 180, tritium, helium) permitted definition of the basic features of surface and deep water circulation, and determination of mean residence times of key water masses (ANDERSON et al., 1989; KRYSELLand WALLACE; 1988; SCHLOSSERet al., 1990). Nine people were involved in the sea-ice program, overlapping with other program areas. Research included ice coring, snow and water sampling, and deploying an array of satellite-tracked buoys. The research effort focused on understanding sea-ice dynamics/ thermodynamics and the impact of sea ice on sedimentation and biologic productivity. Distinct provinces were observed in the ice cover. A thinner basin-marginal zone contained relatively little sediment, while to the north the ice cover was thicker, contained abundant sediment and drifted in the well-defined path of the Transpolar Drift current (PFIRMANet al., 1989a,b; PFIRMANet al., 1990; WOLLENBOR6, 1991). The biology and paleontology working group included 10 investigators. Station work involved box cores, bongo net, biological rosette, fish catcher, multi-net, plankton net, and secchi disk. The focus of this program was to understand the Arctic deep-sea environment, particularly the ecologic influence of Atlantic water and organism response to perennial sea-ice cover. Data from the expedition indicate that both planktonic and benthic communities are influenced by water mass structure in the Nansen Basin, with a major faunal transition between 83° and 84°N (Polarstern Shipboard Scientific Party, 1988; THIEDE et al., 1988; BAUMANN,1990; MUMM, 1991). Using a similar strategy and building on experience gained during the 1987 cruise, another major Arctic expedition took place from August to October 1991. With the combined ice-breaking capability of R.V. Polarstern, the Swedish icebreaker Oden, and the U.S. Coast Guard icebreaker Polar Star, the 1987 Nansen Basin section was extended into the Amundsen and Makarov basins (Fig. 2). Together, the results of the 1987 and 1991 expeditions provide a solid basis for future detailed studies of the central Arctic Ocean. REFERENCES ANDERSONL. G., E. P. JONES,K. P. KOLTERMANN,P. SCHLOSSER,J. H. SwIFr and D. W. R. WALLACE(1989) The first oceanographic section across the Nansen Basin in the Arctic Ocean. Deep-Sea Research, 36,475-482. BAUMANNM. (1990) Coccoliths in sediments of the eastern Arctic Basin. In: Geological history of the polar oceans: Arctic versus Antarctic, U. BELIE and J. THIEDE, editors, NATO ASI Series C308, Kluwer Academic, Amsterdam, pp. 437-445. BELIEU and J. THIEDE,editors (1990) Geological history ofthepolar oceans: Arctic versus Antarctic, NATO ASI Series C308, Kluwer Academic, Amsterdam, 823 pp. BOHRMANNH. (1991) Radioisotopenstratigraphie, Sedimentologie und Geochemie jungquartiirer Sedimente des 6stlichen Arktischen Ozeans (Radioisotope stratigraphy, sedimentology and geochemistry of Late Quaternary sediments from the eastern Arctic Ocean, English abstract). Reports on Polar Research, 95,133 pp. K6HLER S. E. I. (1991) Sp/itquartiire paliio-ozeanographische Entwicklung des Nordpolarmeeres und Europ/iischen Nordmeeres anhand von Sauerstoff- und Kohlenstoff-Isotopenverh/iltnissen der planktischen Foraminifere Neogloboquadrina pachyderma (sin). Thesis Math.-Nat.Fak. Christian-Albrechts-Universitiit Kiel, 104 pp. + Appendix. K6HLERS. E. I. and R. F. SPIELHAGEN(1990) The enigma of oxygen isotope stage 5 in the central Fram Strait. In: Geological history of the polar oceans: Arctic versus Antarctic, U. BELIEand J. THIEDE,editors, NATO ASI Series C308, Kluwer Academic, Amsterdam, pp. 489-497. KRYSELL M. and D. W. R. WALLACE(1988) Arctic Ocean ventilation studied by a suite of anthropogenic halocarbon tracers. Science, 242,746-749. KUBISCHM. (1991) Die Eisdrift im Arktischen Ozean w~ihrend der letzten 250,000 Jahre. Thesis Math.-Nat.Fak. Christian-Albrechts-Universitiit Kiel, 127 pp. + Appendix.
Introduction
$423
MATrHIESSENJ. (1991) Dinoflagellaten-Zysten im Sp~itquartfir des Europ~iischen Nordmeeres: Paloekologie und Pal~io-Ozeanographie. GEOMAR Report, 7,104 pp. MmNERTJ., L. MAYER,G. A. JONESand J. W. KIN6 (1990) Physical and acoustic properties of Arctic Ocean deepsea sediments. In: Geological history of the polar oceans: Arctic versus Antarctic, U. BLEILand J. THmDE, editors, NATO ASI Series C308, Kluwer Academic, Amsterdam, 455-473. MUEHE R. K., H. BOHRMANN,P. K. HOERMANN,J. THIEDE and P. STOFFERS(1991) Spinifex basalts with komatiite-tholeiite trend from the Nansen-Gakkel Ridge (Arctic Ocean). Tectonophysics, 190, 95-108. MUMM N. (1991) Zur sommerlichen Verteilung des Mesozooplanktons im Nansen-Becken, Nordpolarmeer. Berichte Polarforschung, 92,146 pp. NOWACZYKN. R. (1991) Hochaufl6sende Magnetostratigraphie sp~itquartfirer Sedimente arktischer Meeresgebiete (High-resolution magnetostratigraphy of late-Quaternary Arctic marine sediments, English abstract). Reports on Polar Research, 78,187 pp. PAGELSU. (1991) Sedimentologische Untersuchungen und Bestimmung der Karbonatl6sung in sp6tquart/~ren Sedimenten des 6stlichen Arktischen Ozeans. GEOMAR Report, 10, 106 pp. PFIRMANS., J.-C. GASCARD,I. WOLLENBURG,P. MUDIEand A. ABELMANN(1989a) Particle-laden Eurasian Arctic sea ice: observations from July and August 1987. Polar Research, 7, 59-66. PFIRMANS,, I, WOLLENBURG,J. THIEDEand M. LANGE(1989b) Lithogenic sediment on Arctic pack ice: potential aeolian flux and contribution to deep sea sediments. In: Paleoclimatology and Paleometeorology, M. LEINEN and M. SARNTHEI)~,editors, Kluwer Academic, Amsterdam, pp. 463-493. PFIRMANS., M. LANGE,I. WOLLENaURGand P. SCHLOSSER(1990) Sea ice characteristics and the role of sediment inclusions in deep-sea deposition. In: Geological history of the polar oceans: Arctic versus Antarctic, U. BLEIL and J. THIEDE,editors, NATO ASI Series C308, Kluwer Academic, Amsterdam, pp. 187-211. Polarstern Shipboard Scientific Party (1988) Breakthrough in Arctic deep-sea research: The R/V Polarstern expedition 1987. EOS, 69, 665,676--678. SCHLOSSERP., G. BOENISCH,B. KROMERand K. O. MUENNICH(1990) Ventilation rates of the waters in the Nansen Basin of the Arctic Ocean derived from a multitracer approach. Journal of Geophysical Research, 95, 3265-3272. SPmLHAGENR. F. (1991) Die Eisdrift in der Framstrasse wfihrend der letzten 200,000 Jahre. GEOMAR Report, 4, 133 pp. SPIELHAGENR. F., S. PFIRMANand J. THIEDE (1988) Geoscientific report of the ARK IV/3 expedition of R/V POLARSTERN in summer 1987 into the central eastern Arctic Basin. Report 24, GeologischoPal/iontologisches Institut der Universitfit Kiel, Kiel, 106 pp. THIEDEJ. and Shipboard Scientific Party (1988) Scientific cruise report of Arctic Expedition ARK IV/3. Reports on Polar Research, 43,237 pp. THIEDEJ. et al. (1990) Properties and history of the central eastern Arctic sea floor. Polar Record, 26, 1-6. WOLLENBURGI. (1991) Sedimenttransport durch das arktische Meereis. Die rezente lithogene und biogene Materialfracht. Thesis Math.-Nat.Fak. Christian-Albrechts-Universitfit Kiel, 132 pp. + Appendix.
0198--0149/92$5.00+ 0.00 ~) 1992PergamonPressLtd
Introduction Arctic deep-sea research: the Nansen Basin Section STEPHANIE L. PFIRMAN* a n d Jt)RN THIEDE?
(Received 26 March 1992; in revised form 30 March 1992; accepted 30 March 1992)
The papers of this special issue of Deep-Sea Research concern the Arctic Ocean, an area that was inaccessible to full-scale oceanographic investigations until the recent advent of research icebreakers. During the summer of 1987, a multi-disciplinary and international team of investigators aboard the German R.V. Polarstern penetrated the Arctic pack ice as far north as the Gakkel Ridge in the central eastern Arctic basin (Fig. 1). At 86°11'N, R.V. Polarstern attained its northernmost position. Although Soviet nuclear-powered icebreakers had previously reached further north to the North Pole, their expeditions were not designed to conduct systematic deep-sea research. As a result, the 1987 expedition obtained the most complete oceanographic transect in the Arctic Ocean since the epic voyage of Fridtjof Nansen with the Fram in 1893-1896, nearly 100 years before. The 1987 expedition began on 4 July, in Troms6, Norway and ended on 2 September 1987 in Hamburg, Germany. Multi-disciplinary investigations were carried out by 55 scientists and technicians representing 20 institutions from seven countries. Investigations included meteorologic, oceanographic, biologic, geologic and sea-ice sampling. The goals were to assess the modern environment, and to determine, through geological investigations, variations in this environment through time. One of the key reasons driving our interest in the Arctic is to understand its relationship to past climate changes in order to predict potential future changes if global warming proceeds as projected. Global climate models predict that warming due to the anthropogenic enhancement of the greenhouse effect will be greatest in the Arctic and subarctic. This not only would have a dramatic impact on the Arctic environment, but also could have significant feedback on global climate through reduction in snow and ice albedos and changes in oceanic circulation. Oceanographic, geologic and biologic information gathered in 1987 represent a major step forward in documenting this complex system. The marine geology and geophysics working group on board R.V. Polarstern was composed of 28 people. Investigations included: 3.5 kHz and seabeam profiling (where ice *Environmental Defense Fund, 257 Park Avenue South, New York, NY 10010, U.S.A. and Lamont-Doherty Geological Observatory of Columbia University, Palisades, NY 10964, U.S.A. ?GEOMAR, Research Center for Marine Geosciences, Wischhofstrasse 1-3, Building 4, D-2300 Kiel 14, Germany. $419
$420
s.L. PFIRMANand J. THIEDE 88* , - ~
~
88*
Arktis LV/5
86*
86*
84*
84*
177.
\
82*
82*
80* 80*
78* 78 °
-L0*
5*
10*
15"
20 °
Fig. 1. Shiptrackof the 1987expeditionwithR.V. Polarstern (ARKIV/3) fromthe BarentsSea to the GakkelRidge, returningthroughFramStraitto the Norwegian-GreenlandSea.
conditions permitted) as well as gravity measurements, heat flow, box coring, piston coring, gravity coring, giant box coring (Kastenlot) and transmissometer profiling. The main objectives of the marine geology and geophysics program were to assess the relative importance of modern sediment sources and to understand the paleoenvironmental and tectonic evolution of the Nansen Basin. First results from the expedition (Polarstern Shipboard Scientific Party, 1988; SPIELHAGENet al., 1988; THIEDEet al., 1988; BAUMANN, 1990; BLEIL and THmDE, 1990; K6HLER and SPIELHAGEN,1990; MIENERT et al., 1990; THIEDE et al., 1990; BOHRMANN,1991; K6HLER, 1991; KUmSCH, 1991; MATTHIESSEN,1991;
Introduction
$421
180"
ALASKA
,NEWII~F o SIBERIAN ISLANDS
'ELIZABETH I ~ ISLANDS
NO.I.SLANOI
P.
~
FRANZ ,IOSEF .*.~ /LAND
'8' d
8AFFI N BAY ZEMLYA
'%.
",, POLARSTERN 1987
O*
Fig. 2.
---.....
POLARSTERN 1991 ODEN 199!
o
POLAR STAR 1991
Cruise tracks of the 1987 and 1991 Arctic deep-sea expeditions.
MUEHE et al., 1991; NOWACZYK, 1991; PAGELS, 1991; SPIELHAGEN, 1991) reported that recent sedimentation rates are about 1 cm 1000 y-l, similar to those found in the Norwegian-Greenland Sea but an order of magnitude less than in the central Arctic. Many of the giant box cores were more than 4 m long, composed of silty and sandy clays with minor biogenic components and surprisingly little coarse ice-rafted material. Heat flow was extremely high in the rift valley of the Gakkel Ridge, and a box core from the valley contained fragments of altered basalts (MUEHEet al., 1991). The oceanographic working group comprised 24 researchers. Sampling included conductivity, temperature and depth (CTD) measurements coupled with a 24 bottle rosette water sampler, large volume sampling, expendable bathythermographs, expendable current profilers, and heavy metal sampling. The main goals of the oceanographic program were to understand water mass formation, distribution and renewal rates, including the
$422
s . L . PFIRMANand J. THIEDE
circulation of Atlantic and deep waters and to assess the influence of boundary currents and dense shelf water. Analysis of CTD and tracer data (freons, 14C, 180, tritium, helium) permitted definition of the basic features of surface and deep water circulation, and determination of mean residence times of key water masses (ANDERSON et al., 1989; KRYSELLand WALLACE; 1988; SCHLOSSERet al., 1990). Nine people were involved in the sea-ice program, overlapping with other program areas. Research included ice coring, snow and water sampling, and deploying an array of satellite-tracked buoys. The research effort focused on understanding sea-ice dynamics/ thermodynamics and the impact of sea ice on sedimentation and biologic productivity. Distinct provinces were observed in the ice cover. A thinner basin-marginal zone contained relatively little sediment, while to the north the ice cover was thicker, contained abundant sediment and drifted in the well-defined path of the Transpolar Drift current (PFIRMANet al., 1989a,b; PFIRMANet al., 1990; WOLLENBOR6, 1991). The biology and paleontology working group included 10 investigators. Station work involved box cores, bongo net, biological rosette, fish catcher, multi-net, plankton net, and secchi disk. The focus of this program was to understand the Arctic deep-sea environment, particularly the ecologic influence of Atlantic water and organism response to perennial sea-ice cover. Data from the expedition indicate that both planktonic and benthic communities are influenced by water mass structure in the Nansen Basin, with a major faunal transition between 83° and 84°N (Polarstern Shipboard Scientific Party, 1988; THIEDE et al., 1988; BAUMANN,1990; MUMM, 1991). Using a similar strategy and building on experience gained during the 1987 cruise, another major Arctic expedition took place from August to October 1991. With the combined ice-breaking capability of R.V. Polarstern, the Swedish icebreaker Oden, and the U.S. Coast Guard icebreaker Polar Star, the 1987 Nansen Basin section was extended into the Amundsen and Makarov basins (Fig. 2). Together, the results of the 1987 and 1991 expeditions provide a solid basis for future detailed studies of the central Arctic Ocean. REFERENCES ANDERSONL. G., E. P. JONES,K. P. KOLTERMANN,P. SCHLOSSER,J. H. SwIFr and D. W. R. WALLACE(1989) The first oceanographic section across the Nansen Basin in the Arctic Ocean. Deep-Sea Research, 36,475-482. BAUMANNM. (1990) Coccoliths in sediments of the eastern Arctic Basin. In: Geological history of the polar oceans: Arctic versus Antarctic, U. BELIE and J. THIEDE, editors, NATO ASI Series C308, Kluwer Academic, Amsterdam, pp. 437-445. BELIEU and J. THIEDE,editors (1990) Geological history ofthepolar oceans: Arctic versus Antarctic, NATO ASI Series C308, Kluwer Academic, Amsterdam, 823 pp. BOHRMANNH. (1991) Radioisotopenstratigraphie, Sedimentologie und Geochemie jungquartiirer Sedimente des 6stlichen Arktischen Ozeans (Radioisotope stratigraphy, sedimentology and geochemistry of Late Quaternary sediments from the eastern Arctic Ocean, English abstract). Reports on Polar Research, 95,133 pp. K6HLER S. E. I. (1991) Sp/itquartiire paliio-ozeanographische Entwicklung des Nordpolarmeeres und Europ/iischen Nordmeeres anhand von Sauerstoff- und Kohlenstoff-Isotopenverh/iltnissen der planktischen Foraminifere Neogloboquadrina pachyderma (sin). Thesis Math.-Nat.Fak. Christian-Albrechts-Universitiit Kiel, 104 pp. + Appendix. K6HLERS. E. I. and R. F. SPIELHAGEN(1990) The enigma of oxygen isotope stage 5 in the central Fram Strait. In: Geological history of the polar oceans: Arctic versus Antarctic, U. BELIEand J. THIEDE,editors, NATO ASI Series C308, Kluwer Academic, Amsterdam, pp. 489-497. KRYSELL M. and D. W. R. WALLACE(1988) Arctic Ocean ventilation studied by a suite of anthropogenic halocarbon tracers. Science, 242,746-749. KUBISCHM. (1991) Die Eisdrift im Arktischen Ozean w~ihrend der letzten 250,000 Jahre. Thesis Math.-Nat.Fak. Christian-Albrechts-Universitiit Kiel, 127 pp. + Appendix.
Introduction
$423
MATrHIESSENJ. (1991) Dinoflagellaten-Zysten im Sp~itquartfir des Europ~iischen Nordmeeres: Paloekologie und Pal~io-Ozeanographie. GEOMAR Report, 7,104 pp. MmNERTJ., L. MAYER,G. A. JONESand J. W. KIN6 (1990) Physical and acoustic properties of Arctic Ocean deepsea sediments. In: Geological history of the polar oceans: Arctic versus Antarctic, U. BLEILand J. THmDE, editors, NATO ASI Series C308, Kluwer Academic, Amsterdam, 455-473. MUEHE R. K., H. BOHRMANN,P. K. HOERMANN,J. THIEDE and P. STOFFERS(1991) Spinifex basalts with komatiite-tholeiite trend from the Nansen-Gakkel Ridge (Arctic Ocean). Tectonophysics, 190, 95-108. MUMM N. (1991) Zur sommerlichen Verteilung des Mesozooplanktons im Nansen-Becken, Nordpolarmeer. Berichte Polarforschung, 92,146 pp. NOWACZYKN. R. (1991) Hochaufl6sende Magnetostratigraphie sp~itquartfirer Sedimente arktischer Meeresgebiete (High-resolution magnetostratigraphy of late-Quaternary Arctic marine sediments, English abstract). Reports on Polar Research, 78,187 pp. PAGELSU. (1991) Sedimentologische Untersuchungen und Bestimmung der Karbonatl6sung in sp6tquart/~ren Sedimenten des 6stlichen Arktischen Ozeans. GEOMAR Report, 10, 106 pp. PFIRMANS., J.-C. GASCARD,I. WOLLENBURG,P. MUDIEand A. ABELMANN(1989a) Particle-laden Eurasian Arctic sea ice: observations from July and August 1987. Polar Research, 7, 59-66. PFIRMANS,, I, WOLLENBURG,J. THIEDEand M. LANGE(1989b) Lithogenic sediment on Arctic pack ice: potential aeolian flux and contribution to deep sea sediments. In: Paleoclimatology and Paleometeorology, M. LEINEN and M. SARNTHEI)~,editors, Kluwer Academic, Amsterdam, pp. 463-493. PFIRMANS., M. LANGE,I. WOLLENaURGand P. SCHLOSSER(1990) Sea ice characteristics and the role of sediment inclusions in deep-sea deposition. In: Geological history of the polar oceans: Arctic versus Antarctic, U. BLEIL and J. THIEDE,editors, NATO ASI Series C308, Kluwer Academic, Amsterdam, pp. 187-211. Polarstern Shipboard Scientific Party (1988) Breakthrough in Arctic deep-sea research: The R/V Polarstern expedition 1987. EOS, 69, 665,676--678. SCHLOSSERP., G. BOENISCH,B. KROMERand K. O. MUENNICH(1990) Ventilation rates of the waters in the Nansen Basin of the Arctic Ocean derived from a multitracer approach. Journal of Geophysical Research, 95, 3265-3272. SPmLHAGENR. F. (1991) Die Eisdrift in der Framstrasse wfihrend der letzten 200,000 Jahre. GEOMAR Report, 4, 133 pp. SPIELHAGENR. F., S. PFIRMANand J. THIEDE (1988) Geoscientific report of the ARK IV/3 expedition of R/V POLARSTERN in summer 1987 into the central eastern Arctic Basin. Report 24, GeologischoPal/iontologisches Institut der Universitfit Kiel, Kiel, 106 pp. THIEDEJ. and Shipboard Scientific Party (1988) Scientific cruise report of Arctic Expedition ARK IV/3. Reports on Polar Research, 43,237 pp. THIEDEJ. et al. (1990) Properties and history of the central eastern Arctic sea floor. Polar Record, 26, 1-6. WOLLENBURGI. (1991) Sedimenttransport durch das arktische Meereis. Die rezente lithogene und biogene Materialfracht. Thesis Math.-Nat.Fak. Christian-Albrechts-Universitfit Kiel, 132 pp. + Appendix.