Carbon geochemistry of plankton-dominated samples in the Laptev and East Siberian shelves: Contrasts in suspended particle composition

Recent Arctic studies suggest that sea ice decline and permafrost thawing will affect phytoplankton dynamics and stimulate heterotrophic communities. However, in what way the plankton composition will change as the warming proceeds remains elusive. Here we investigate the chemical signature of the plankton-dominated fraction of particulate organic matter (POM) collected along the Siberian Shelf. POM (>10 mu m) samples were analysed using molecular biomarkers (CuO oxidation and IP25 ) and dual-carbon isotopes (delta C-13 and Delta C-14). In addition, surface water chemical properties were integrated with the POM (>10 mu m) dataset to understand the link between plankton composition and environmental conditions.