Last updated: November 18, 2022
Article
Linkages Between Global Climate Change and Dissolved Organic Carbon in Arctic Lakes
Frozen Arctic soils (permafrost) has stored carbon for thousands of years. But as the soils thaw, especially ice-rich permafrost, carbon is rapidly released. Numerous studies are underway to understand the impact of global climate change on carbon cycles related to thawing permafrost. Many studies have looked at soils and the release of dissolved organic carbon (DOC) from ice melt. This study looks at carbon in Arctic lakes. Lakes created by or supplemented with thawing permafrost are widespread in the Arctic and dynamic across the landscape. This is the first study to synthesize existing datasets across northern permafrost regions and explore the linkages between DOC concentration and environmental properties (such as permafrost zone, ecoregion, deposit types, ground ice content, and soil organic carbon content).
We analyzed 2167 water samples from 1,833 lakes across the Arctic in permafrost regions of Alaska, Canada, Greenland, and Siberia. Our dataset (PeRL-DOCv1) shows that the DOC concentration of a lake depends on its environmental properties, especially on permafrost extent and ecoregion, as well as vegetation, which is the most important driver of lake DOC in this study. The median lake DOC concentrations in our study regions are 12.4 mg L^-1 in Siberia, 12.3 mg L^-1 in Alaska, 10.3 mg L^-1 in Greenland, and 4.5 mg L^-1 in Canada.
We found higher lake DOC concentrations at boreal permafrost sites compared to tundra sites and significantly higher DOC concentrations in lakes in regions with organic-rich Pleistocene-age ice (yedoma) deposits compared to non-yedoma lakes. The PeRL-DOCv1 dataset will be fundamental to quantify a pan-Arctic lake DOC pool for estimations of the impact of lake DOC on the global carbon cycle and climate change.
First pan-Arctic assessment of dissolved organic carbon in lakes of the permafrost region
Abstract
Lakes in permafrost regions are dynamic landscape components and play an important role for climate change feedbacks. Lake processes such as mineralization and flocculation of dissolved organic carbon (DOC), one of the main carbon fractions in lakes, contribute to the greenhouse effect and are part of the global carbon cycle. These processes are in the focus of climate research, but studies so far are limited to specific study regions. In our synthesis, we analyzed 2,167 water samples from 1,833 lakes across the Arctic in permafrost regions of Alaska, Canada, Greenland, and Siberia to provide first pan-Arctic insights for linkages between DOC concentrations and the environment. Using published data and unpublished datasets from the author team, we report regional DOC differences linked to latitude, permafrost zones, ecoregions, geology, near-surface soil organic carbon contents, and ground ice classification of each lake region. The lake DOC concentrations in our dataset range from 0 to 1130 mg L−1 (10.8 mg L−1 median DOC concentration). Regarding the permafrost regions of our synthesis, we found median lake DOC concentrations of 12.4 mg L−1 (Siberia), 12.3 mg L−1 (Alaska), 10.3 mg L−1 (Greenland), and 4.5 mg L−1 (Canada). Our synthesis shows a significant relationship between lake DOC concentration and lake ecoregion. We found higher lake DOC concentrations at boreal permafrost sites compared to tundra sites. We found significantly higher DOC concentrations in lakes in regions with ice-rich syngenetic permafrost deposits (yedoma) compared to non-yedoma lakes and a weak but significant relationship between soil organic carbon content and lake DOC concentration as well as between ground ice content and lake DOC. Our pan-Arctic dataset shows that the DOC concentration of a lake depends on its environmental properties, especially on permafrost extent and ecoregion, as well as vegetation, which is the most important driver of lake DOC in this study. This new dataset will be fundamental to quantify a pan-Arctic lake DOC pool for estimations of the impact of lake DOC on the global carbon cycle and climate change.
Stolpmann, L., C. Coch, A. Morgenstern, J. Boike, M. Fritz, U. Herzschuh, K. Stoof-Leichsenring, Y. Dvornikov, B. Heim, J. Lenz, A. Larsen, K. Walter Anthony, B. Jones, K. Frey, and G. Grosse. 2021. First pan-Arctic assessment of dissolved organic carbon in lakes of the permafrost region. Biogeosciences 18: 3917-3936.