Inventories and behavior of particulate organic carbon in the Laptev and East Siberian seas

Laura Sánchez-García, Vanja Alling, Svetlana Pugach, Jorien Vonk, Bart Van Dongen, Christoph Humborg, Oleg Dudarev, Igor Semiletov, Örjan Gustafsson

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52 Citations (Scopus)

Abstract

[1] Fluvial and erosional release processes in permafrost-dominated Eurasian Arctic cause transport of large amounts of particulate organic carbon (POC) to coastal waters. The marine fate of this terrestrial POC (terr-POC), water column degradation, burial in shelf sediments, or export to depth, impacts the potential for climate-carbon feedback. As part of the International Siberian Shelf Study (ISSS-08; August-September 2008), the POC distribution, inventory, and fate in the water column of the extensive yet poorly studied Eurasian Arctic Shelf seas were investigated. The POC concentration spanned 1-152 mM, with highest values in the SE Laptev Sea. The POC inventory was constrained for the Laptev (1.32 ± 0.09 Tg) and East Siberian seas (2.85 ± 0.20 Tg). A hydraulic residence time of 3.5 ± 2 years for these Siberian shelf seas yielded a combined annual terr-POC removal flux of 3.9 ± 1.4 Tg yr?1. Accounting for sediment burial and shelf-break exchange, the terr-POC water column degradation was ?2.5 ± 1.6 Tg yr?1, corresponding to a first-order terr-POC degradation rate constant of 1.4 ± 0.9 yr?1, which is 5-10 times faster than reported for terr-DOC degradation in the Arctic Ocean. This terr-POC degradation flux thus contributes substantially to the dissolved inorganic carbon excess of 10 Tg C observed during ISSS-08 for these waters. This evaluation suggests that extensive decay of terr-POC occurs already in the water column and contributes to outgassing of CO2. This process should be considered as a geographically dislocated carbon-climate coupling where thawing of vulnerable permafrost carbon on land is eventually adding CO2 above the ocean.

Original languageEnglish
Article numberGB2007
JournalGlobal Biogeochemical Cycles
Volume25
Issue number2
DOIs
Publication statusPublished - 2011
Externally publishedYes

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Environmental Science(all)
  • Atmospheric Science

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    Sánchez-García, L., Alling, V., Pugach, S., Vonk, J., Van Dongen, B., Humborg, C., Dudarev, O., Semiletov, I., & Gustafsson, Ö. (2011). Inventories and behavior of particulate organic carbon in the Laptev and East Siberian seas. Global Biogeochemical Cycles, 25(2), [GB2007]. https://doi.org/10.1029/2010GB003862