Release of ballast material during sea-ice melt enhances carbon export in the Arctic Ocean
| Type | : | ACL |
|---|---|---|
| Nature | : | Production scientifique |
| Au bénéfice du Laboratoire | : | Non |
| Statut de publication | : | Publié |
| Année de publication | : | 2024 |
| Auteurs (9) | : | SWOBODA Steffen KRUMPEN T NÖTHIG E,m METFIES K RAMONDENC Simon WOLLENBURG Jutta FAHL K PEEKEN Ilka IVERSEN Morten |
| Revue scientifique | : | Proceedings of the National Academy of Sciences nexus |
| Volume | : | |
| Fascicule | : | |
| Pages | : | |
| DOI | : | 10.1093/pnasnexus/pgae081 |
| URL | : | https://doi.org/10.1093/pnasnexus/pgae081 |
| Abstract | : | Globally, the most intense uptake of anthropogenic carbon dioxide (CO2) occurs in the Atlantic north of 50°N, and it has been predicted that atmospheric CO2 sequestration in the Arctic Ocean will increase as a result of ice-melt and increased primary production. However, little is known about the impact from pan-Arctic sea-ice decline on carbon export processes. We investigated the potential ballasting effect by sea-ice derived material on settling aggregates and carbon export in the Fram Strait by combining 13-years of vertical flux measurements with benthic eDNA analysis, laboratory experiments, and tracked sea-ice distributions. We show that melting sea-ice in the Fram Strait releases cryogenic gypsum and terrigenous material, which ballasts sinking organic aggregates. As a result, settling velocities of aggregates increased ≤ 10-fold, resulting in ≤ 30% higher carbon export in the vicinity of the melting ice-edge. Cryogenic gypsum is formed in first-year sea-ice, which is predicted to increase as the Arctic is warming. Simultaneously, less sea-ice forms over the Arctic shelves, which is where terrigenous material is incorporated into sea-ice. Supporting this, we found that terrigenous fluxes from melting sea-ice in the Fram Strait decreased by >80% during our time-series. Our study suggests that terrigenous flux will eventually cease when enhanced sea-ice melt disrupts trans-Arctic sea-ice transport and thus, limit terrigenous-ballasted carbon flux. However, the predicted increase in Arctic primary production and gypsum formation may enhance gypsum-ballasted carbon flux and compensate lowered terrigenous fluxes. It is thus unclear if sea-ice loss will reduce carbon export in the Arctic Ocean. |
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| Commentaire | : | - |
| Tags | : | - |
| Fichier attaché | : | - |
| Citation | : |
Swoboda S, Krumpen T, Nöthig EM, Metfies K, Ramondenc S, Wollenburg J, Fahl K, Peeken I, Iversen M (2024) Release of ballast material during sea-ice melt enhances carbon export in the Arctic Ocean. PNAS Nexus | doi: 10.1093/pnasnexus/pgae081
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