Advances in Earth Science
Limin Hu,Xuefa Shi,Jun Ye,Yuying Zhang. Advances in the Sources and Sink of Sedimentary Organic Carbon in the East Siberian Arctic Shelf[J]. Advances in Earth Science, 2020, 35(10): 1073-1086.
The East Siberian Arctic Shelf （ESAS） is one of the widest and shallowest continental shelves in the world. In the context of the global warming and rapid Arctic changes， the sources， transport and burial of sedimentary Organic Carbon （OC） in this area have experienced significant changes with spatial heterogeneity， which could be related to the sea-ice reduction， permafrost degradation， increased runoff and intensified coastal erosion. The sedimentary OC is mainly contributed by Terrestrial Organic Carbon （TerrOC） in the western East Siberian Sea and the Laptev Sea， and the coastal erosion increases the flux of Permafrost Carbon （PF/C） with a positive climate feedback effect. The Chukchi Sea has high organic carbon burial efficiency， where the seasonal variation of sea ice has direct effect on the source and sink of OC. Under the influence of hydrodynamic sorting， the cross-shelf transport times of TerrOC from the Lena estuary to the shelf edge requires approximately 3 000～4 000 years， by coupling with a significant geochemical differentiation and degradation. There existed spatio-temporal variation for the OC burial on the ESAS， and the large amount and rapid deposition of highly-reactive PF/C from the land to the sea could have important significance for the Arctic soil carbon， the OC mineralization in the aquatic environment， and CO2 outgassing. The following research should strengthen the application of the comprehensive geochemical indices and the compound-specific isotope method， emphasizing the relation between the sea-ice and the sources and sink of the OC. By coupling with the models of regional carbon cycle， we should emphasize the integration of the modern process and geological records， proxy records with the numerical simulation， which is necessary to better understand the sources and sink of sedimentary OC and the climate and environmental effect from the varied timescales.