Dre Jorien Vonk - Thawing permafrost: the fate of soil organic matter in the aquatic environment

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Dre Jorien Vonk, Vrije Universiteit Amsterdam

Lundi 15 février 2021 à 10h00 - Monday, February 15, 2021 at 10:00 am
Lien Zoom / Zoom link: https://mcgill.zoom.us/j/87890935860?pwd=WVo2SVF0UHlvSEc3NlZKZ2pGYzllZz09
Résumé / abstract:

As the Arctic permafrost region warms, its large organic carbon (OC) pool becomes vulnerable to decomposition. This generates greenhouse gases (GHG) that in turn fuel increased surface warming: the permafrost carbon feedback. Higher temperatures will jump-start the coupling between the carbon and hydrological cycle, allowing for the introduction of previously frozen OC pools into aquatic systems. This lateral, or horizontal, aquatic flux remains largely unknown in contrast to the relatively well-studied vertical flux, GHG emission on land. Horizontal OC release either occurs via gradual thaw, slowly leaching OC into aquatic systems, or via abrupt thaw, where ground-ice melt causes destructive surface collapse and slumping of OC into aquatic systems. Both types of thaw facilitate decomposition of OC (generating GHG) but also re-bury OC into sediments (sequestering OC). The relative importance of decomposition versus burial is unknown.

Here I will present the first outcomes from my project THAWSOME, funded by the European Research Council, that started four years ago. The main focus of our team is particulate organic matter as this is the dominant form in which permafrost thaw-induced organic matter is released into aquatic systems. With results from three different study regions (Herschel Island/Canada, Peel Plateau/Canada, Kolyma River/ Siberia ) I will shed more light on the relative importance of decomposition versus burial of thawed permafrost OC and therewith its climatic implications.

Passcode: 509500

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Thawing permafrost: the fate of soil organic matter in the aquatic environment

Ajouter au calendrier 2021-02-15 10:00:00 2021-05-10 17:29:07 Dre Jorien Vonk - Thawing permafrost: the fate of soil organic matter in the aquatic environment As the Arctic permafrost region warms, its large organic carbon (OC) pool becomes vulnerable to decomposition. This generates greenhouse gases (GHG) that in turn fuel increased surface warming: the permafrost carbon feedback. Higher temperatures will jump-start the coupling between the carbon and hydrological cycle, allowing for the introduction of previously frozen OC pools into aquatic systems. This lateral, or horizontal, aquatic flux remains largely unknown in contrast to the relatively well-studied vertical flux, GHG emission on land. Horizontal OC release either occurs via gradual thaw, slowly leaching OC into aquatic systems, or via abrupt thaw, where ground-ice melt causes destructive surface collapse and slumping of OC into aquatic systems. Both types of thaw facilitate decomposition of OC (generating GHG) but also re-bury OC into sediments (sequestering OC). The relative importance of decomposition versus burial is unknown. Here I will present the first outcomes from my project THAWSOME, funded by the European Research Council, that started four years ago. The main focus of our team is particulate organic matter as this is the dominant form in which permafrost thaw-induced organic matter is released into aquatic systems. With results from three different study regions (Herschel Island/Canada, Peel Plateau/Canada, Kolyma River/ Siberia ) I will shed more light on the relative importance of decomposition versus burial of thawed permafrost OC and therewith its climatic implications. Passcode: 509500 Geotop admin@example.com America/New_York public