What is the role of hydrological connectivity in shaping carbon dioxide concentrations and emissions in Arctic lakes?

The role of Arctic lakes as sites of carbon processing is amplified with rapidly changing climate leading to permafrost thaw and altered hydrological connections. Land-to-water hydrological connections represent an important regulatory mechanism of carbon transport, especially in systems with low rainfall-runoff ratios such as the Arctic tundra. While the importance of hydrological connectivity has been inferred locally, there is no assessment of its role at a pan-Arctic scale across different lake types. To better understand how hydrological connectivity controls annual aquatic carbon dioxide concentrations and emissions, we collated previously published and unpublished data from more than 200 Arctic lakes distributed across permafrost regions in Alaska, Northern Canada, Greenland, Siberia, and Scandinavia. To characterize land-to-lake connections, we delineated lake catchments and characterized climate, land topography, soil properties, and land use within each watershed. High hydrological connectivity is associated with relatively low carbon dioxide concentrations, low emissions, and low across-lake variability. Regions with low hydrological connectivity characterized by low effective precipitation have very high across-lake variability of both concentrations and fluxes, having both the lowest and the highest measured concentrations and fluxes. Lakes with the highest emissions (top 25%) are in low-relief lowlands in the zone of continuous/discontinuous permafrost and have smaller catchments with a high proportion of wetlands.

Primary Presenter: Vaclava Hazukova, University of Maine (vaclava.hazukova@maine.edu)

Authors:

Vaclava Hazukova, University of Maine  (vaclava.hazukova@maine.edu)

Fredrik Sundberg, Umeå University  (fredrik.sundberg@umu.se)

Cristian Gudasz, Umeå University  (cristian.gudasz@umu.se)

Chunlin Song, Sichuan University  (songchunlin@scu.edu.cn)

Matthew Bogard, Lethbridge University  (matthew.bogard@uleth.ca)

Joshua Dean, University of Bristol  (josh.dean@bristol.ac.uk)

Anders Jonsson, University of Umeå  (anders.jonsson@umu.se)

Erik Lundin, Swedish Polar Research Secretariat  (erik.lundin@polar.se)

Suzanne Tank, University of Alberta  (suzanne.tank@ualberta.ca)

Jasmine Saros, University of Maine  (jasmine.saros@maine.edu)

Jan Karlsson, University of Umeå  (jan.p.karlsson@umu.se)