Lipids in ocean particulate matter and bottom sediments

Lipid contents both in particulate matter and bottom sediments decreases with passage from the shelf toward the open ocean. Lipid concentration in particulate matter collected by a separator (Ls) decreases by a factor of 7 (from 7.05 to 0.95 % of dry matter), while in particulate matter collected on filters (Lf) it decreases by a factor of 13 (from 78 to 6 µg/l) in the vicinity of the Limpopo River and by a factor of 6 (from 74 to 13 µg/l) in the vicinity of the Zambezi River. Concentration of Lf also decreased with depth. In the upper sediment layers lipid concentration was 0.0028-0.039% of dry matter; all mud samples were richer in lipids, than sand samples. During sedimentogenesis there is an increase in proportion of lipids relative to other classes of organic matter, proportion of low-polarity compounds increases among the lipids, and proportion of hydrocarbons rises among these compounds. Sediments inherit composition of particulate matter to the greatest degree in the vicinity of river mouths.

Zooplankton and seston in the White Sea and its chemical composition

A technique of zooplankton net sampling at night in the Kandalaksha and Dvinskii Bays and during the full tide in the Onezhskii Bay of the White Sea allowed us to obtain "clean" samples without considerable admixtures of terrigenous particulates. Absence of elements-indicators of the terrigenous particulates (Al, Ti, and Zr) in the EDX spectra allows to conclude that ash composition of tested samples is defined by constitutional elements comprising organic matter and integument (chitin, shells) of plankton organisms. A quantitative assessment of accumulation of ca. 40 chemical elements by zooplankton based on a complex of modern physical methods of analysis is presented. Values of the coefficient of the biological accumulation of the elements (Kb) calculated for organic matter and the enrichment factors (EF) relative to Clarke concentrations in shale are in general determined by mobility of the chemical elements in aqueous solution, which is confirmed by calculated chemical speciation of the elements in the inorganic subsystem of surface waters of Onezhskii Bay.