Skip to main content
U.S. flag

An official website of the United States government

Hydrologic and landscape controls on dissolved organic matter composition across western North American Arctic lakes

December 22, 2022

Northern high-latitude lakes are hotspots for cycling dissolved organic carbon (DOC) inputs from allochthonous sources to the atmosphere. However, the spatial distribution of lake dissolved organic matter (DOM) is largely unknown across Arctic-boreal regions with respect to the surrounding landscape. We expand on regional studies of northern high-latitude DOM composition by integrating DOC concentrations, optical properties, and molecular-level characterization from lakes spanning the Canadian Taiga to the Alaskan Tundra. Lakes were sampled during the summer from July to early September to capture the growing season. DOM became more optically processed and molecular-level aromaticity increased northward across the Canadian Shield to the southern Arctic and from interior Alaska to the Tundra, suggesting relatively greater DOM incorporation from allochthonous sources. Using water isotopes (δ18O-H2O), we report a weak overall trend of increasing DOC and decreasing aromaticity in lakes that were hydrologically isolated from the landscape and enriched in δ18O-H2O, while within-region trends were stronger and varied depending on the landscape. Finally, DOC correlated weakly with chromophoric dissolved organic matter (CDOM) across the study sites, suggesting that autochthonous and photobleached DOM were a major component of the DOC in these regions; however, some of the northernmost and wetland-dominated lakes followed pan-Arctic riverine DOC-CDOM relationships, indicating strong contributions from allochthonous inputs. As many lakes across the North American Arctic are experiencing changes in temperature and precipitation, we expect the proportions of allochthonous and autochthonous DOM to respond with aquatic optical browning with greater landscape connectivity and more internally produced DOM in hydrologically isolated lakes.

Publication Year 2023
Title Hydrologic and landscape controls on dissolved organic matter composition across western North American Arctic lakes
DOI 10.1029/2022GB007495
Authors Martin R. Kurek, Fenix Garcia-Tigreros, Kimberly Wickland, Karen E. Frey, Mark Dornblaser, Robert G. Striegl, Sydney F. Niles, Amy M. McKenna, Pieter J.K Aukes, Ethan D. Kyzivat, Chao Wang, Tamlin M. Pavelsky, Laurence C. Smith, Sherry L. Schiff, David Butman, Robert G.M. Spencer
Publication Type Article
Publication Subtype Journal Article
Series Title Global Biogeochemical Cycles
Index ID 70239227
Record Source USGS Publications Warehouse
USGS Organization WMA - Earth System Processes Division