Stable oxygen and carbon isotopes from the planktonic foraminifera Neogloboquadrina pachyderma in the Western Arctic surface sediments： Implications for water mass distribution

Neogloboquadrina pachyderma is the most abundant planktonic foraminifera species found in the modern polar oceans. The δ^18O and δ^13C of N. pachyderma from the Western Arctic Ocean sediments were analyzed to reveal the implications of the proxies to environmental changes. The δ^18O from N. pachyderma in the Chukchi Sea reflect the water mass distribution in this area. Heavier δ^18O values were found along the Anadyr Current （AC） and lighter values in the central and eastern Chukchi Sea..These may reflect the freshwater signal from the Alaska Coastal Current （ACC） and Bering Sea Shelf Water （BSSW）. The light δ^18O signature in the high Arctic basin comes from the freshwater stored in the Arctic surface layer. The δ^18O distribution pattern in the Chukchi Sea is also influenced by the current system. High primary productivity along the AC results in heavy δ^18O. The relatively low primary productivity and the freshwater component from the BSSW and ACC may be the reason for this light δ^13C signal in the central and eastern Chukchi Sea. Our data reveal the importance of well ventilated Pacific Water through the Chukchi Sea into the Arctic Ocean.