Abstract
This study is focused on CDOM fluorescence of the Laptev Sea and East Siberian Sea surface waters. The preliminary results are based on ten samples collected along three transects from the estuarine regions of Khatanga, Kolyma and Indigirka rivers to the continental slope. Fluorescence spectra were recorded in wide ranges of excitation (230-550 nm) and emission (240-650 nm) wavelengths. Humification and biological/autochthonous indices were calculated in order to determine the degree of maturation of DOM and autochthonous biological activity in water. 'Blue shift' parameters of CDOM fluorescence (Δ270-310; Δ355-310) for the runoff-influenced surface waters were estimated as (26 nm; 33 nm), (24 nm; 40 nm), and (25 nm; 36 nm) for the Khatanga, Indigirka, and Kolyma transect, respectively. Desalinated surface waters of the Laptev Sea were found to be under a strong influence of humic substances, while in case of East Siberian Sea surface waters CDOM is characterized by a predominance of an autochthonous component. Evolution of CDOM fluorescence within the Laptev Sea and East Siberian Sea shelf is considered.