One major oceanic heat source for the European Arctic region comes from the extension of the northbound flow of the warm and saline North Atlantic Current (NAC) into the Arctic. The current is involved in shaping both climate and environmental changes in the Arctic as evidenced from instrumental time series (Aagaard and Carmack 1989; Schauer et al., 2004). Although reconstructions of Holocene Arctic climate change have revealed a somewhat consistent picture of the long-term (>millennial scale) paleoceanographic development (e.g., Lubinski et al, 2001, de Vernal et al., 2005; Andrews and Dunhill, 2004; Hald et al., 2004; Slubowska et al., 2007), there is still a lack of high-resolution paleoceanographic records that can provide more detailed descriptions of the spatial and temporal variability of the inflow of the warm and saline North Atlantic Current (NAC) into the Arctic. In this study we have investigated a compiled marine record (NP94-51) representing the last 17,000 years from a high accumulation area on the continental shelf, i.e. the Hinlopen Trough, northern Svalbard margin. This site has been chosen due to its present location within the inflow of Atlantic Water into the Arctic Ocean. The age model for the core is based on 18 AMS radiocarbon dates, yielding an average sedimentation rate of 53 cm/kyr (range 20-110 cm/kyr).

The paleoceanographic reconstructions are inferred from the content of benthic and planktic foraminifera and IRD. The last 17,000 years of paleoceanographic development on northern Svalbard margin is clearly illustrated by the relative abundance changes of the species Cassidulina reniforme and Elphidium excavatum. During the initial deglaciation period these two species dominated the benthic foraminiferal assemblages, indicating glaciomarine conditions in the Hinlopen Trough (Slubowska et al., 2005; Koc et al., 2002). Atlantic water indicative species increased at the expense of these two species during the Bølling-Allerød signaling the initial Atlantic water flow to the Arctic and ameliorated bottom water conditions while the onset of the Younger Dryas shows a return to glaciomarine conditions inferred from an increase of both E. excavatum and C. reniforme. During the Holocene, these two species show opposite trends; C. reniforme dominates in the early Holocene indicating inflow of saline but chilled AW while E. excavatum starts increasing at ca. 7000 cal yr and dominates from around 4000 cal yr BP suggesting overall deterioration of the paleoceanographic conditions due to less influence of AW water and increased glacial activity (Slubowska et al. 2005; Slubowska et al., 2007). Unexpectedly the late Holocene dominance of E. excavatum starts to decrease around 2000 cal yr BP and this trend continues towards present time. The shift in E. excavatum at around 2000 cal yr BP is accompanied by gradual increases in the relative abundance of species M. barleeanum, Buccella spp. and Islandiella spp. while the content of C. reniforme remains low. Moreover, the faunal composition of the last c. 2000 years is unprecedented compared to the last 17,500 years. We, therefore, infer from the faunal data that a fundamental shift in the Arctic environmental regime related to changes in the ocean circulation occurred around 2000 years ago. The causes for this environmental change at 2000 years ago is, however, not clear.