Carbon from permafrost in Siberian rivers

A study explores carbon release from permafrost and peat into rivers. Climate warming is expected to release dormant carbon from peat and permafrost, a portion of which will enter rivers. Large spatial heterogeneity in permafrost thaw hinders understanding of continent-wide carbon mobilization patterns. Birgit Wild and colleagues combined decade-long observational records of 14C in organic carbon from four major Siberian rivers with a database of 14C fingerprints of potential carbon sources to quantify the fraction of organic carbon in the rivers that originated in permafrost and peat deposits (PP-C). Around 17% of total organic carbon in the rivers could be attributed to permafrost and peat. PP-C contributed to around 12% of dissolved organic carbon (DOC), and to more than half of particulate organic carbon (POC). Seasonal patterns in PP-C contributions suggest that PP-C in DOC derived primarily from gradual leaching of surface soils, whereas the PP-C fraction of POC reflected abrupt collapse of deep Holocene and/or Pleistocene deposits. Differences in the relative amounts of dissolved versus particulate PP-C between rivers were consistent with differences in the type and extent of permafrost in their basins. According to the authors, the 14C content of carbon in rivers can be used to monitor release of PP-C in response to climate warming.

Article #18-11797: "Rivers across the Siberian Arctic unearth the patterns of carbon release from thawing permafrost," by Birgit Wild et al.

MEDIA CONTACT: Birgit Wild, Stockholm University, SWEDEN; tel: +46-76-561-00-02; e-mail: birgit.wild@aces.su.se; Örjan Gustafsson, Stockholm University, SWEDEN; tel: +46-703247317; e-mail: orjan.gustafsson@aces.su.se

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