Contrasting regimes for organic matter degradation in the East Siberian Sea and the Laptev Sea assessed through microbial incubations and molecular markers

• Published in: Marine chemistry 2015-03, Vol.170, p.11-22
• Main Authors: Karlsson, E.S., Brüchert, V., Tesi, T., Charkin, A., Dudarev, O., Semiletov, I., Gustafsson, Ö.
• Format: Article
• Language: English
• Subjects: Applied Environmental Science; Arctic Ocean; Carbon; Coastal shelf; Continental margin; CuO oxidation; Decomposition; Degradation; Incubations; Lignin; Marine chemistry; Markers; Microorganisms; Organic geochemistry; Organic matter lability; Origins; Permafrost; Pools; Reactivity; Regression; Remineralization; Sediment; Sediments; Terrestrial organic carbon; tillämpad miljövetenskap; Wax lipids
• ISSN: 0304-4203; 1872-7581; 1872-7581
• DOI: 10.1016/j.marchem.2014.12.005

Compositional studies of organic matter on the East Siberian Arctic Shelf (ESAS) suggest that different terrestrial carbon pools have different propensities for transport and/or degradation. The current study combined laboratory-based microbial degradation experiments with earlier published degradation-diagnostic composition of several classes of terrestrial biomarkers on the same sediments to investigate differences and driving forces of terrestrial organic matter (TerrOM) degradation in two biogeochemically-contrasting regimes of the ESAS. The incubation-based anaerobic degradation rates were consistently higher (by average factor of 6) in the East Siberian Sea Kolyma Paleoriver Channel (ESS-KPC) (15μmolCO2gOC−1day−1) compared to the Laptev Sea Buor-Khaya Bay (LS-BKB) (2.4μmolCO2gOC−1day−1). The reported molecular markers show similarities between the terrestrial carbon pools in the two systems, but impose contrasting degradation regimes in combination with the incubation results. For the LS-BKB, there was a strong relationship between the degradation rates and the three lignin phenol-based degradation proxies (r2=0.93–0.96, p