Introduction. Siberian river run-off into the Kara Sea: Characterization, quantification, variability and environmental significance - An introduction (D.K. Futterer, E.M. Galimov). A. Modern discharge: Data and modelling. River run-off influence on the water mass formation in the Kara Sea (S. Pivovarov, R. Schlitzer, A. Novikhin). Salt intrusions in Siberian river estuaries: Observations and model experiments in Ob and Yenisei (I.H. Harms, U. Hubner et al.). Atlantic Water flow to the Kara Sea: Comparing model results with observations (M.J. Karcher, M. Kulakov et al.). Freshwater distribution and brine waters in the southern Kara Sea in summer 1999 as depicted by &dgr;18O results (D. Bauch, H. Erlenkeuser et al.). DIC stable carbon isotope pattern in the surface waters of the southern Kara Sea, Sep. 2000 (H. Erlenkeuser, H.H. Cordt et al.). Stable isotope ratios in bivalve shells: Suitable recorders for salinity and nutrient variability in the Kara Sea? (J. Simstich, V. Stanovoy et al.). Geochemical processes in the Yenisei River and Estuary (B. Beeskow, V. Rachold). Radionuclides in the water column and surface sediments of the Ob and Yenisei rivers and adjacent Kara Sea shelf (O.V. Stepanets, A. Borisov et al.). B. Discharge and biological processes. Phytoplankton distribution in the inner Kara Sea: A comparison of three summer investigations (E.-M. Nothig, Y. Okolodkov et al.). The freshwater phytoplankton biomass and its role in the formation of a highly productive zone on the Ob-Yenisei shallows (southern Kara Sea) (P.R. Makarevich, N.V. Druzhkov et al.). Distribution of meroplankton in the southern Kara Sea in relation to local hydrographic pattern (I. Fetzer). Benthic fauna of the southern Kara Sea (N.V. Denisenko, E. Rachor, S.G. Denisenko). The southern Kara Sea ecosystem: Phytoplankton, zooplankton and benthos communities influenced by river run-off (H. Deubel, M. Engel et al.). Organic carbon consumption of the Kara Sea macrozoobenthos: A first assessment (M. Klages, H. Deubel, E. Rachor). C. Discharge and organic carbon cycle. Dissolved organic matter (DOM) in the estuaries of Ob and Yenisei and the adjacent Kara Sea, Russia (H. Kohler, B. Meon et al.). Particle fluxes from short-term sediment trap deployments in late summer in the southern Kara Sea (B. Gaye-Haake, D. Unger et al.). Biomarkers in surface sediments from the Ob and Yenisei estuaries and the southern Kara Sea: Evidence for particulate organic carbon sources, pathways, and degradation (K. Fahl, R. Stein et al.). Contribution of biogenic methane to ikaite formation in the Kara Sea: Evidence from the stable carbon isotope geochemistry (L.A. Kodina, V.G. Tokarev et al.). D. Discharge and sediment records. Diatom assemblages in surface sediments of the Kara Sea (Siberian Arctic) and their relationship to oceanological conditions (Ye.I. Polyakova). Holocene siliciclastic and organic carbon fluxes in the Ob and Yenisei estuaries and the adjacent inner Kara Sea: Quantification, variability, and paleoenvironmental implications. (R. Stein, K. Fahl et al.). A Holocene marine pollen record from the northern Yenisei Estuary (southeastern Kara Sea, Siberia) (M. Kraus, J. Matthiessen, R. Stein). Holocene sediment budget and sedimentary history of the Ob and Yenisei estuaries (K. Dittmers, F. Niessen, R. Stein).