Grain Size Distribution, Organic Carbon, and Geochemical Markers in the Surface Layer of Bottom Sediments in the Northeastern Kara Sea

The upper layer of bottom sediments in the northeastern Kara Sea is studied. It is shown that the sediment composition is dominated by silt, while the percentage of sand increases towards the coast. The organic carbon content (average value 1.1 wt %) is close to the average content in Kara Sea sediments, increasing at deep-sea stations. The linear correlation found between the organic carbon content and surface area of sediments shows adsorption on particle surfaces and is the predominant form of organic matter (OM) accumulation in the sediments. The average n-alkane concentration in the analyzed samples is 1.1 μg/g of sediment; the distribution spectrum is dominated by odd high-molecular homologues of terrigenous origin.