Colored dissolved organic matter of the Kara and Laptev seas in the case of eastern distribution of Ob and Yenisei River runoff

Abstract

The absorbance and fluorescence of chromophoric fraction of dissolved organic matter (CDOM) have proved to be optical markers to study estuarine and coastal mixing, dynamics of quantitative and qualitative changes in DOM, and also necessary as preconditions for remote sensing techniques. Optical properties and distribution of CDOM of the Kara and Laptev seas were investigated during the 72nd cruise of the R/V Akademik Mstislav Keldysh in August-September 2018. Autochthonous material was found to be most abundant. The predominance of terrestrial-derived humic substances was observed for the Ob and Yenisei river-influenced regions. The transport of allochthonous DOM to the Laptev Sea occurred through the Vilkitsky Strait mainly along the coast of the Taimyr Peninsula, and the content of humic-like CDOM decreases about twofold at 50 m depth.