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

Abstract

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