Bounding cross-shelf transport time and degradation in Siberian-Arctic land-ocean carbon transfer.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29476050.
- Also identified by DOI 10.1038/s41467-018-03192-1 and PMC identifier 5824890.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The burial of terrestrial organic carbon (terrOC) in marine sediments contributes to the regulation of atmospheric CO<sub>2</sub> on geological timescales and may mitigate positive feedback to present-day climate warming. However, the fate of terrOC in marine settings is debated, with uncertainties regarding its degradation during transport. Here, we employ compound-specific radiocarbon analyses of terrestrial biomarkers to determine cross-shelf transport times. For the World's largest marginal sea, the East Siberian Arctic shelf, transport requires 3600 ± 300 years for the 600 km from the Lena River to the Laptev Sea shelf edge. TerrOC was reduced by ~85% during transit resulting in a degradation rate constant of 2.4 ± 0.6 kyr<sup>-1</sup>. Hence, terrOC degradation during cross-shelf transport constitutes a carbon source to the atmosphere over millennial time. For the contemporary carbon cycle on the other hand, slow terrOC degradation brings considerable attenuation of the decadal-centennial permafrost carbon-climate feedback caused by global warming.