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Carbon dioxide supersaturation in high‐elevation oligotrophic lakes and reservoirs in the Sierra Nevada, California
Author(s) -
Cohen Adam P.,
Melack John M.
Publication year - 2020
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.11330
Subject(s) - carbon dioxide , supersaturation , environmental science , flux (metallurgy) , oceanography , carbon dioxide in earth's atmosphere , ecosystem , elevation (ballistics) , hydrology (agriculture) , atmospheric sciences , climate change , geology , ecology , chemistry , biology , geometry , mathematics , geotechnical engineering , organic chemistry
To better understand the contribution of alpine lakes to global CO 2 emissions, carbon dioxide concentrations and fluxes to the atmosphere were measured in five high‐elevation lakes and five reservoirs in the Sierra Nevada, California. Median summer surface concentrations of dissolved CO 2 (reservoirs: 21.1 μ M, lakes: 23.7 μ M) were supersaturated for most of the ice‐free season. Median diffusive flux of CO 2 was low as compared to other inland waters (lakes: 260 mg CO 2 m −2 d −1 , reservoirs: 192 mg CO 2 m −2 d −1 ). Linear mixed modeling demonstrated that the length of ice cover, persisting for 5–9 months and allowing for accumulation of under‐ice CO 2 , was a strong predictor of summer surface CO 2 . During the ice‐free period, surface evasion of CO 2 was highest for the first 40 d after ice‐off when carbon dioxide that had accumulated during winter was released, although supersaturation and evasion continued until fall at most sites despite low rates of ecosystem metabolism. This study suggests that the contribution of high‐elevation, oligotrophic lakes and reservoirs in the Sierra to global CO 2 emissions are small despite persistent supersaturation, and are primarily driven by the duration of ice cover.