Organic Matter in the Ocean: Indicators of Biogeochemical Processes

The article presents informative organogeochemical indicators used in oceanology to characterize biogeochemical processes. A classification based on data on suspended particulate matter, plankton, benthos, bottom sediments, and sea, river, and pore water has been developed. Clusters have been identified that include the elemental and isotopic composition of organic matter (OM), the group composition of lipids, aliphatic and alicyclic hydrocarbons, higher alcohols, macromolecular acids and ketones, isoprenoids, lignin and its structural monomers, and PAHs. The most informative indices are considered, which make it possible to assess the genesis of the original OM, the degree of its transformation, sources, and the ratio of aquatic and terrigenous components. These indices reflect the influx of riverine and aeolian material and permafrost thawing and make it possible to reconstruct the temperature of river waters and coastal upwellings. They significantly complement biooceanological, lithological, and geochemical studies and expand the biogeochemical methodology for studying the carbon cycle.