Low organic carbon burial efficiency in arctic lake sediments. Issue 6 (27th June 2014)

• Record Type: Journal Article
• Authors: Sobek, S.; Anderson, N. J.; Bernasconi, S. M.; Del Sontro, T.
• Is Part Of: Journal of geophysical research. Volume 119:Issue 6(2014)
• Page Start: 1231
• Page End: 1243
• Publication Date: 2014-06-27
• Subjects: Geobiology -- Periodicals; Biogeochemistry -- Periodicals; Biotic communities -- Periodicals; Geophysics -- Periodicals; 577.14
• DOI: 10.1002/2014JG002612
• Languages: English
• ISSNs: 2169-8953

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>Many arctic landscapes are rich in lakes that store large quantities of organic carbon in their sediments. While there are indications of highly efficient carbon burial in high‐latitude lakes, the magnitude and efficiency of carbon burial in arctic lake sediments, and thus their potential as carbon sinks, has not been studied systematically. We therefore investigated the burial efficiency of organic carbon (OC), defined as the ratio between OC burial and OC deposition onto the sediment, in seven contrasting lakes in western Greenland representing different arctic lake types. We found that the OC burial efficiency was generally low in spite of the differences between lake types (mean 22%, range 11–32%), and comparable to lakes in other climates with similar organic matter source and oxygen exposure time. Accordingly, post‐depositional degradation of sediment organic matter was evident in the organic matter C:N ratio, δ<sup>13</sup>C and δ<sup>15</sup>N values during the initial ~50 years after deposition, and proceeds simultaneously with long‐term changes in, e.g., productivity and climate. Pore water profiles of dissolved methane suggest that post‐depositional degradation may continue for several centuries in these lakes, at very low rates. Our results demonstrate that the regulation of the sediment OC burial efficiency is no different in arctic lakes than in other lakes, implying that the efficiency of the carbon sink in lake sediments depends similarly on environmental conditions irrespective of latitude.</p> </abstract>