Oriol Grau; blogging from Toolik, Alaska

I am a MSCA researcher of the research group ‘Plants and Ecosystems’ (PLECO) at the University of Antwerpen, Belgium. I focus on the impacts of permafrost thaw on the biogeochemistry of arctic peatlands, and my research is done within the framework of the FROSTLAND project. Permafrost peatlands in the Arctic typically develop as patterned-ground systems, through the development of ice-wedges forming a polygonal microrelief with higher rims enclosing a central depression. Polygon mires are commonly found in drained thermokarst lakes, floodplains and river deltas and occupy very vast regions in the Arctic. The functioning of these ecosystems is still poorly understood because active layer thickness, permafrost relief, water level, peat thickness and vegetation vary greatly over short distances making it difficult to assess the overall balance of permafrost aggradation /degradation, greenhouse gas fluxes and C sequestration /release. Permafrost thawing is associated with ecosystem-driven feedbacks, that may keep site conditions stable in spite of climate change. This intrinsic dynamism is still poorly understood and adds uncertainty on how polygon tundra will respond to climate warming. The INTERACT funded project THARCPEAT2 aims to shed light on the knowledge gaps highlighted above by investigating the variety and variability of permafrost characteristics across geomorphic features (e.g. polygon centers, rims and ice-wedges) in polygon mires.

In september 2022 I came to Toolik field station, on the north slope of the Brooks range in Northern Alaska together with two wonderful colleagues, Olga Margalef (University of Barcelona, Catalonia) and John Couwenberg (University of Greifswald, Germany). Our aim was to estimate the area occupied by degraded vs. non degraded permafrost features in polygon mires. To do so we used drone imagery and ground-validated data. This will provide novel information on fine-scale differences in permafrost stability across polygon peatlands. These data will be combined with plant, soil and water chemistry data that we collected in a previous campaign to upscale the stocks of C, N and P in the active layer and in the permafrost in this dominant ecosystem in the Arctic. We are very grateful to INTERACT and the staff at Toolik Field Station, who were amazingly helpful.

Polygon mire north of Toolik where permafrost is still well preserved. By Oriol Grau
Polygon mire north of Toolik where permafrost is thawing and the peatland is becoming a lake. By Oriol Grau
What are peatlands and why are permafrost peatlands important? By John Couwenberg

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