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Quale è il ruolo biogeochimico delle piattaforme continentali? Articolo con contributo di T. Tesi (Ismar-CNR)

Datazioni su biomarcatori terrestri rivelano per la prima volta il tempo di trasporto del materiale organico terrestre nei sedimenti marini

Friday 09 March 2018

Quale è il ruolo biogeochimico delle piattaforme continentali? Articolo con contributo di T. Tesi (Ismar-CNR)

 

L'articolo è disponibile on line al link della rivista: https://www.nature.com/articles/s41467-018-03192-1

Broder, L; Tesi, T; Andersson, A; Semiletov, I; Gustafsson, O    BO
Bounding cross-shelf transport time and degradation in Siberian-Arctic land-ocean carbon transfer
NATURE COMMUNICATIONS, 9 10.1038/s41467-018-03192-1 FEB 23 2018

Abstract

The burial of terrestrial organic carbon (terrOC) in marine sediments contributes to the regulation of atmospheric CO2 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 similar to 85% during transit resulting in a degradation rate constant of 2.4 +/- 0.6 kyr(-1). 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.


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