Assessing Holocene Environmental Change in the Kara Sea, Eurasian Arctic

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Little is known about the environmental change in the Eurasian Arctic, a major site for the formation and passage of sea-ice and water masses in the Arctic Ocean. The knowledge of climatic and oceanographic fluctuations in this region on a millenial and submillenial scale is especially important in view of the special role of the Arctic in the modern global change. This project is aimed at the first time-constrained reconstruction of Holocene paleo-environments in the Kara Sea, which is strongly influenced by both the extensive continental run-off and the Atlantic water advection. The Kara Sea sediments contain a unique record of variations in the discharge of Siberian rivers, Atlantic water flow, and the formation of bottom waters. A number of sediment cores and surface sediment samples were collected recently in the Kara Sea. Cores from key sites located in a corridor between the estuaries of Ob' and Yenisey Rivers and the marginal Saint Anna Trough, are chosen for a study of the Holocene environmental change on a millenial to centennial time-scale. Core stratigraphy will be time-constrained by AMS 14C dating of in situ calcareous faunal remnants. Mineralogical, geochemical, and grain-size analyses will be used to assess sediment dispersal sources and depositional environments. Stable isotopes will be measured on planktonic foraminifers from the northern Kara Sea to understand the relation between the Siberian river discharge and oceanographic change in the eastern Arctic Ocean. Modern distributional patterns of foraminifers and ostracodes with respect to the Kara Sea hydrology will be established to provide reliable paleo-environmental reconstructions for the Holocene. Results of this collaborative research will significantly improve our knowledge of environmental change in the Eurasian Arctic. Reconstruction of amplitude and timing of riverine and Atlantic water pulses throughout the Holocene will reveal new insights in mechanisms of heat and water vapor transfer from the North Atlantic to the Arctic, and their controls on the extent of sea ice and formation of water masses in the Arctic Ocean.