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Conceptual model of an Arctic landscape, highlighting the geomorphic processes that regulate the mobilization and fate of carbon released from thawing permafrost. As permafrost thaws, organic carbon is released from bedrock and permafrost soils. Once released from previously frozen soils, this organic carbon is susceptible to oxidation (generating CO2), methanogenesis (generating CH4), or it may be delivered to rivers. Geomorphology, geochemistry, and hydrologic connectivity govern the fate of organic carbon released from thawing permafrost.
Is climate change accelerating carbon loss from the Arctic landscape?
The Arctic is warming four times as fast as the rest of the planet (Rantanen et al., 2022).
A landscape, which has been frozen for thousands of years, is now thawing.
Permafrost soils hold nearly two times as much carbon than is currently in our atmosphere, but permafrost thaw is releasing this carbon.
The largest Arctic Rivers are now carrying 12% more water than during 1981-2010*, causing faster erosion rates.
*Data from NOAA's 2021 Arctic Report Card
We are only beginning to understand the carbon-climate feedback in the Arctic . . .
I study the feedbacks between climate change, permafrost thaw, and water chemistry in Arctic landscapes. The goal of my research is to understand how Arctic landscapes are physically changing, and how those changes affect water chemistry and carbon export from rivers. One of my research projects focuses on the Canning River in northern Alaska, where I have conducted field work to collect water, soil, and sediment samples from throughout the river system. I am working to analyze the spatial and temporal patterns of the change in the water chemistry carbon export, and link that change to patterns of permafrost thaw and other landscape characteristics.
Permafrost river banks of the Canning RIver in northern Alaska. Photo credit: Josh Koch
Canning River, Alaska
Canning River, Alaska
Erosion and sediment transport control the carbon storage capacity of the landscape, yet the link between fluvial morphodynamics and carbon cycling is poorly understood in Arctic river systems where climate change may have an outsized impact on landscape dynamics. Our team is studying the Canning River on the north slope of the Brooks Range, Alaska to identify the key processes triggering the export of organic carbon from a continuous permafrost landscape.
Feedbacks between river ice breakup, peak snowmelt runoff, and the growth and decay of aufeis can trigger profound geomorphic change in the river system, such as channel widening, crevasse-splays, and lateral erosion. We are studying how this geomorphic change can drive enhanced bank erosion and downstream export of organic carbon.Â
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