Canadian permafrost as a source of easily-degraded organic carbon

The February issue of “Organic Geochemistry” will include a paper by David Grewer and colleagues from the University of Toronto and Queen’s University, Canada which investigates what happens to organic carbonĀ in the Canadian High Arctic when the surface permafrost layer slips and erodes. This is a paper that I was involved in, not as a researcher but as a reviewer, helping to make sure that published scientific research is novel, clear and correct.

Map of Cape Bounty in the Canadian High Arctic
Map of Cape Bounty in the Canadian High Arctic

The researchers visited a study site in Cape Bounty, Nunavut, to study a process known as Permafrost Active Layer Detachments (ALDs). The permafrost active layer is the top part of the soil, the metre or so that thaws and re-freezes each year. ALDs are erosion events where the thawed top layer is transported down the hillslope and towards the river. Rivers can then erode and transport the activated material downstream towards the sea.

The team used organic geochemistry and nuclear magnetic resonance spectroscopy to find out which chemicals were present in the river above and below the ALDs. The found that the sediment eroded from the ALDs contains carbon that is easily degraded and can break down in the river, releasing CO2 to the atmosphere and providing food for bacteria and other micro-organisms in the water.

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