Dissolved organic carbon export and its contribution to the carbon budget in a boreal peat landscape undergoing rapid permafrost thaw

Oliver Sonnentag, Université de Montréal, oliver.sonnentag@umontreal.ca (Presenter)
Julien Fouché, Université de Montréal, julien.fouche@tuta.io
Manuel Helbig, McGill University, mhelbig85@gmail.com
Karoline Lillie, Université de Montréal, karoline.wischnewski@gmail.com
Gabriel Hould Gosselin, Université de Montréal, ghgosselin@gmail.com
William Quinton, Wilfrid Laurier University, wquinton@wlu.ca
Tim Moore, McGill University, tim.moore@mcgill.ca

In boreal lowlands with warm and thin isolated permafrost, increasing temperatures cause a thaw-induced expansion of permafrost-free wetlands at the expense of forested permafrost peat plateaus. Permafrost thaw associated with warming may enhance decomposition of soil organic matter but also modify dissolved organic carbon (DOC) export to aquatic systems, which may play a non-negligible role for the carbon budget. We quantified the DOC export from a boreal peat landscape in the southern Northwest Territories (Canada) and estimate its contribution to the net ecosystem carbon balance. DOC export ranged from 2.5 to 4.0 g C m-2 from April to August, which accounted for ~51% (2014), 25% (2015) and 16% (2016) of the annual net ecosystem exchange. Our findings suggest that thawing boreal peat landscapes along the southern limit of permafrost are currently carbon neutral and increased vegetation productivity may turn the site into a weak sink.

Poster Location ID: 51

Session Assigned: Carbon Dynamics