Organic carbon flow in the Ob, Yenisey Rivers and Kara Sea of the Arctic region

Stable carbon isotope and elemental C/N ratios of the organic fraction of a set of samples along a transect in the Ob and Yenisey Rivers into the Kara Sea in the Arctic were measured. Previously, the concentrations of (PU)-P-239.240 and Cs-137 in these same samples had been determined. The coupled measurements were carried out to assess possible connectivity between organic carbon How into the Kara Sea and transport of radioactive nuclides in this marine environment. Organic carbon flow into the Kara Sea is influenced significantly by terrigenous sources carried by the Ob and Yenisey Rivers. The carbon isotope-organic carbon relationship provides evidence that a rich source of terrigenous carbon exists in the riverine system. A weak, but significant relationship between stable carbon isotope ratio and Cs-137 suggests that most of the (CS)-C-137 is derived from riverine particles, as compared to Pu which is also derived from in situ scavenging within the water column. (C) 2001 Elsevier Science Ltd. All rights reserved.