Isotopic composition of carbon in organic matter of sediments and particulate matter from the Northwest Pacific

A study was made of isotopic composition of carbon in lipids found in three samples of separate particulates and in eight bottom sediment samples collected in a from the Simushir Island towards the open Pacific Ocean. Average d13C of lipids from particulates was 2.3 per mil lower than one of sediments. Humic acids from sediments are the most isotopically heavy fraction (d13C = -21.2 per mil). Isotopic composition of carbon in lipids depended on their total content in samples and on composition of sediments. Formation of isotopically heavy lipids in the surface layer of sediments may be associated with biogeochemical resynthesis of humic acids.