The Siberian Rivers, especially the Lena, contribute most of the freshwater, organic matter and silicate to the Amerasian basin of the Arctic Ocean and to the Transarctic current. A central idea behind this proposal is to link the land hydrology in watersheds of the Lena, Yana, Indigirka, and Kolyma with the transport and fate of riverine waters to the Laptev and East-Siberian seas through variability of atmospheric forcing. Our driving hypotheses are:

• Recent changes in Arctic climate are leading to increased frequency of cyclones, warming, melting of permafrost, and increased river runoff that can lead to environmental changes in the Arctic seas. Increased atmospheric forcing and runoff cause an increase in the flux of dissolved and solid terrestrial material to the Laptev and East-Siberian seas. Increased offshore transport of terrestrial material is expected to show important contributions to sediment accumulation and CNP cycling in the Arctic Ocean.


• A change from the cyclonic mode of wind-driven circulation (the positive AO) to the anti-cyclonic mode (the negative AO) determines major environmental changes in the Laptev and East-Siberian seas. The two dominant modes of atmospheric forcing are expected to explain differences in the freshwater budget, circulation, ice condition and hydrochemical regime in the East-Siberian region.

To test our hypothesis, we propose to determine the inter-annual and intra-seasonal variability of atmospheric forcing over Siberia and the adjacent part of the Arctic Ocean that influences the land hydrology, runoff, water circulation and biogeochemical regime. We propose to do this by acquiring, synthesing, integrating and comparing land-shelf (meteorology, land and marine hydrology, hydrochemistry) data for two seminal areas of the Arctic: 1) the Lena -Laptev Sea system, and 2) the East-Siberian land-shelf system, which is influenced strongly by the Pacific water inflow.

An important component of this project is an analysis of the existing collection of frozen water, sediment and particulate matter sampled in winter (April-May, 2002) and summer (August-September, 2000) in the Laptev and East-Siberian seas. A transect of the eastern Laptev and East-Siberian seas corresponds to a number of geographically critical contrasts in the Arctic system. This area remains largely understudied and provides an excellent natural laboratory to use our approach to make progress on an improved understanding of the interactions across atmosphere-land-ocean system and their impacts on freshwater dynamics and biogeochemistry.