Methane in Arctic Lakes

Research Project: Year-round autonomous sampling of methane in Arctic lakes

Methane is a potent greenhouse gas, the release of which from Arctic sources is poised to increase with climate warming. The majority of methane flux to the Arctic atmosphere is estimated to come from soils and small lakes, although these estimates are based on few direct observations with large uncertainties. Our team was recently funded to measure methane concentrations in frozen lakes continuously throughout the Arctic winter using autonomous sampling devices, to more thoroughly address the variability in the methane flux from Arctic lakes to the atmosphere.

This project expands upon a successful pilot study that included the initial testing of autonomous continuous fluid sampler and sensor systems. The proposed expansion will involve additional capabilities and the deployment of a sampling unit in each of six small lakes along a north-south gradient in the Mackenzie River delta in the Canadian Arctic for a nine-month period, spanning the winter season. With these data will we characterize the physical, chemical, and microbial conditions in the water column to elucidate hydrologic, microbial, and weathering processes during the winter season, when methane builds in lake water under the ice cover. We hypothesize that sudden (week, days, or even hours) releases of methane, following spring flooding and ice cover breakup, produce a distinct atmospheric flux from Arctic lakes that would otherwise be missed, since most logistically reasonable sampling occurs in the summer months when methane concentrations in these lakes are low or below detection.

This project is supported through funding from the US National Science Foundation’s Division of Polar Programs through awards to Dr. Beth N. Orcutt (Award ID 1416961) at the Bigelow Laboratory for Ocean Sciences, to Dr. Laura L. Lapham (Award ID 1417128) of the University of Maryland Center for Environmental Science, and to Dr. C. Geoff Wheat (Award ID 1417815) of the University of Mississippi.