The Kara Sea Expedition of RV "Akademik Boris Petrovw1997: First Results of a Joint Russian-German Pilot Study Edited by Jens Matthiessen, Oleg V. Stepanets, Ruediger Stein, Dieter K. Füttererand Eric M. Galimov Ber. Polarforsch. 300 (1 999) ISSN 01 76 - 5027 ra Sea Expedition of ademik Boris Petrov" 199 sults of a Joint Russian- erman Pilot Study Jens Matthiessen Alfred Wegener lnstitute for Polar and Marine Research ColumbusstraßeBremerhaven] Germany e-mail: jmatthiessen Qawi-bremerhaven.de Oleg V. Stepanets Vernadsky lnstitute of Geochemistry and Analytical Chemistry Kosygin Street, MOSCOW~Russia e-mail: elkorQgeokhi.msk.su Ruediger Stein Alfred Wegener lnstitute for Polar and Marine Research ColumbusstraßeBremerhaven, Germany e-mail: rstein @awi-bremerhaven.de Dieter K. Füttere Alfred Wegener lnstitute for Polar and Marine Research ColumbusstraßeBremerhaven] Germany e-mail: dfuettererQawi-bremerhaven.de Eric M. Galimov Vernadsky lnstitute of Geochemistry and Analytical Chemistry Kosygin Street] MOSCOW~Russia e-mail: galimovQgeokhi.msk.su TABLE OF CONTENT Preface ............................................................................................ 1 FütfererD, K. and Galimov, E.M. The expedition to the Kara Sea in Summer 1997: Summary of the shipboard scientific results .......................................................5 Matfhiessen, J., Sfepanets, 0,V. and the shipboard scientific party Oceanography and Hydrochemistry .............................................. 1 7 Pivovarov, S, V, and Stanovoy, V. V, Variability of water temperature, concentration of dissolved oxygen, alkalinity and silicon in the Vega Strait (Kara Sea) ..............................................18 Gribanov, V.V., lvanov, B.V., Stanovoy, V.V. and Churun, V.N. Micro- and mesoscale oscillations of thermohaline characteristics in the coastal zone in the vicinty of the Yenisei Gulf .............................................27 Marine Biology.............................................................................. 3 5 NöthigE.-M. and Kattner, G. Distribution of phytoplankton biomass and nutrient concentrations ..................37 Halsband, C. and Hirche, H.J. The role of mesozooplankton for the transformation of organic matter .............45 Poltermann, M., Deubel, H., Klages, M. and ßachorE. Benthos communities: Composition, diversity patterns and biomass distribution as first indicators for utilization and transformation processes of organic matter......................................................................................................... 51 Korsun, S. Benthic foraminifera in the Ob Estuary, West Siberia.......................................... 59 Matthiessen, J. and Boucsein, B. Palynomorphs in surface water of the Ob and Yenisei estuaries: Organic-walled tracers for riverine water ................................................................ 71 Organic Geochemistry ................................................................... 7 9 Erlenkeuser, H., Spielhagen, ßand Taldenkova, E. Stable isotopes in modern water and bivalve samples from the southem Kara Sea ...................................................................................... 80 Kodina, L.A., Bogacheva, M.P., Vlasova, L.N,, Meschanov, S.L. and Ljutsarev, S. V. Isotope geochemistry of particulate organic carbon in the Yenisei Estuary: Sources and regularities of distribution.................................................................. 91 Amon, ßM. W, and Spitzy, A. Distribution of dissolved organic carbon during estuarine mixing in the southern Kara Sea........................................................................................ 102 Neumann, K. Nitrogenous organic matter in surface sediments in the estuaries of the Ob and Yenisei rivers ....................................................................................110 50ucseir1, B., Fahl, K., Siebold, M. and Stein, ß Quantity and quality of organic carbon in suriace sediments of the Ob and Yenisei estuaries and adjacent coastal areas: Marine productivity vs. terrigenous input....................................................................................................... 116 Damm, E. Manganese, iron and nutrients in Pore water profiles from the Ob and Yenisei estuaries (Kara Sea) ............................................................127 Radio-Geochemistry .............i ...................................................... 1 3 1 Stepanets, 0.V., Borisov, A,P. and Solov'eva, G. Yu. Distribution of anthropogenic radionuclides in the estuaries of Ob and Yenisei rivers and adjacent Kara Sea ...............................................132 Kremlyakova, N. Yu., Ligaev, A.N., Stepanets, 0.V, and Sizov, E.M. Determination of radiostrontium in sea water and bottom sediments from the southeastem Kara Sea ............................................................................141 Miroshnikov, A. Y. and Asadulin, A.A, Tracking and distribution of radioactive contamination from nuclear plants to the bottom sediments of the Ob and Yenisei rivers and the Kara Sea Basin.......................................................................................... 145 Sedimentology and lnorganic Geochemistry ..............................154 Lukashin, V.N., Ljutsarev, S,V,, Krasnyuk, A.D., Shevchenko, V.P. and ßusakovV. Yu. Suspended particulate matter in the Ob and Yenisei estuaries ......................155 MüllerC, and Stein, ß Grain-size distribution and clay-mineral composition in surface sediments and suspended matter of the Ob and Yenisei rivers.......................................... 179 Krasnyuk, A.D. and Vanshteyn, 5.G. Heavy metals in bottom sediments from the estuaries of the rivers Ob and Yenisei ..........................................................................................................188 Schoster, F, and Stein, ß Major and minor elements in suriace sediments of Ob and Yenisei estuaries and the adjacent Kara Sea ...................................................................196 Micropaleontology ....................................................................... 20 8 Polyakova, Ye.1, New data On diatom distribution in surface sediments of the Kara Sea .........209 Matthiessen, J. Distribution of palynomorphs in surface sediments from the Ob and Yenisei estuaries (Kara Sea, Arctic Ocean) ....................................................................... 222 Addresses of Contributors ........................................................... 236 PREFACE FüttererD.K.1, Galimov, E.2 1 Alfred Wegener Institute, Bremerhaven, Germany 2 Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow, Russia The Arctic Ocean can be considered a giant estuary fed by rivers draining a significant part of the Eurasian continent and of North America. A major amount of this fresh water stems from the Russian rivers Pechora, Ob, Yenisei and the Lena. Freshwater input from these rivers logether with meltwater from Arctic glaciers and ice sheets is of critical importance in influencing the global climate system since formation of deep water masses in the North Atlantic as a major climatic driving force is heavily dependent On salinity variations derived from the Arctic Ocean. The Siberian rivers together with their adjacent shelf seas represent also an important Part of a bio-geochemical system within which extensive interaction between continent and ocean is a significant component. The sediments accumulating in the Arctic Ocean basins and shelf seas are rich in organic matter. Virtually nothing is known about the sources of this organic matter - terrestrial or marine - and on the processes that have led to its accumulation. A better understanding of these factors is necessary to assess the role of the Arctic Ocean as a potential sink for carbon dioxide. The sediments of the Arctic shelf seas are well known to represent significant sources of climatically relevant gases such as methane which is released at the sea floor. At present, the Arctic region faces two most serious ecological problems. The first one is related to the discovery of huge gas and oil resources. The hydrocarbon reserves On the shelves are estimated at tens of trillions of cubic meters of gas and tens of billions of metric tons of oil what equals to about a quarter of the world's hydrocarbon reserves. The prospect of an intense economic development in the Arctic region requires the knowledge of the bio- geochemical background as the principal basis for handling and managing principal environmental issues. Another serious problem is a potential radioactive pollution of the Arctic Ocean and particularly the Kara Sea due to fallout from nuclear testing activities and radioactive wastes from various sources. The distribution and behavior of radionuclides in the ocean is determined by their sources and a number of geochemical factors such as composition of particulate matter, conditions of reworking of the organic substance, the resulting redox conditions in the sediments and the hydrophysical parameters of the sea water. To get a better idea of the relevant modern processes being active in this continent-ocean system along a strong salinity gradient from the Ob and Yenisei estuaries, over the shallow shelf of the eastern and northern Kara Sea and continental slope into the Open Arctic Ocean and to answer the various questions mentioned above, a bilateral Russian-German multi-disciplinary Programme has been defined. As a first step and pilot study a scientifically