Abstract
The East Siberian Sea (ESS) is the largest, shallowest and most icebound Arctic marginal sea. It receives substantial input of terrigenous material and climate-vulnerable old organic carbon from both coastal erosion and rivers draining the extensive permafrost-covered watersheds. This study focuses on the interannual variability and spatial distribution of suspended particulate matter (SPM) in the surface and bottom waters of the ESS during the ice-free period in 2000, 2003, 2004, 2005 and 2008. We report on the composition and variability of particulate organic carbon (POC), total nitrogen (TN), POC/TN ratios, carbon and nitrogen isotopes (δ13C, δ15N) and provide estimates of the contribution of terrestrial organic carbon (terrOC) based on the δ13C isotopic values. The results show that interannual SPM distribution and elemental-isotopic characteristics of POC differ significantly between the western biogeochemical province (WBP; West of 165oE) and the eastern biogeochemical province (EBP; East of 165oE) of the ESS. The SPM mean concentration in the WBP is almost an order of magnitude higher than in the EBP. From west-to-east of the ESS, SPM tends to become more depleted in δ15N, while the δ13C becomes isotopically heavier. This trend can be explained by a shift in organic matter sources from terrigenous origin (erosion of the coastal ice complex and riverine POC) to becoming dominantly from marine plankton. The maximum contribution of terrOC to POC reached 99% in parts of the WBP, but accounts for as low as 1% in parts of the EBP. At the same time, the type of atmospheric circulation and its associated regime of both water circulation and ice transport control a displacement of the semi-stable biogeochemical border between WBP and EBP to the east or to the west if compared to its long-term average position near 165oE. Our multi-year investigation provides a robust observational basis for better understanding of the transport and fate of terrigenous material upon entering the ESS shelf waters. Our results also provide deeper insights into the interaction in the land-shelf sea system of the largest shelf sea system of the World Ocean, the East Siberian Arctic Shelf system.
Original language | English |
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Article number | 102903 |
Pages (from-to) | 1-19 |
Number of pages | 19 |
Journal | Progress in Oceanography |
Volume | 208 |
Early online date | 27 Sept 2022 |
DOIs | |
Publication status | Published - Nov 2022 |
Bibliographical note
Funding Information:This work was supported by the Russian Science Foundation (grant 21-77-30001 to IS). Field campaigns were supported by the assignement of the Russian Ministry of Science and Higher Education (theme 0211-2021-0010 to the POI) as well as by the Knut and Alice Wallenberg Foundation (KAW contract 2011.0027 to ÖG). Furthermore, this study was partly supported by the Russian Science Foundation (grant nos. 19-17-00058 to AC, 21-17-00027 to IP). Additional support was provided by the Russian Foundation for Basic Research (grant no. 20-05-00545 to SP) and by grants from the President of the Russian Federation to support young Russian scientists (projects MK-1774.2021.1.5 to AR and MK-3476.2021.1.5 to EG). Gap filling samples from the western ESS were supported by the Russian Ministry of Science and Higher Education (grant ID: 075-15-2020-928) to the HSE. Further support was provided by the Swedish Research Council (grant 2021-06670 to JM, grant 2017-01601 to ÖG).
Publisher Copyright:
© 2022 Elsevier Ltd
Keywords
- Arctic
- East Siberian Sea
- Organic matter
- Spatial and interannual variability
- Suspended particulate matter transport