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River Inflow Dominates Methane Emissions in an Arctic Coastal System
Author(s) -
Manning Cara C.,
Preston Victoria L.,
Jones Samantha F.,
Michel Anna P. M.,
Nicholson David P.,
Duke Patrick J.,
Ahmed Mohamed M. M.,
Manganini Kevin,
Else Brent G. T.,
Tortell Philippe D.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl087669
Subject(s) - estuary , bay , environmental science , greenhouse gas , methane , hydrology (agriculture) , carbon dioxide , arctic ice pack , inflow , oceanography , arctic , discharge , sea ice , melt pond , cryosphere , atmospheric sciences , geology , drift ice , drainage basin , ecology , geotechnical engineering , cartography , geography , biology
We present a year‐round time series of dissolved methane (CH 4 ), along with targeted observations during ice melt of CH 4 and carbon dioxide (CO 2 ) in a river and estuary adjacent to Cambridge Bay, Nunavut, Canada. During the freshet, CH 4 concentrations in the river and ice‐covered estuary were up to 240,000% saturation and 19,000% saturation, respectively, but quickly dropped by >100‐fold following ice melt. Observations with a robotic kayak revealed that river‐derived CH 4 and CO 2 were transported to the estuary and rapidly ventilated to the atmosphere once ice cover retreated. We estimate that river discharge accounts for >95% of annual CH 4 sea‐to‐air emissions from the estuary. These results demonstrate the importance of resolving seasonal dynamics in order to estimate greenhouse gas emissions from polar systems.