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Impact of terrestrial carbon input on methane emissions from an Alaskan Arctic lake
Author(s) -
Mazéas Olivier,
von Fischer Joseph C.,
Rhew Robert C.
Publication year - 2009
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 - 10.1029/2009gl039861
Subject(s) - thermokarst , permafrost , tundra , active layer , methane , environmental science , arctic , hydrology (agriculture) , greenhouse gas , erosion , carbon fibers , atmospheric sciences , oceanography , geology , geomorphology , ecology , layer (electronics) , chemistry , materials science , composite number , composite material , biology , geotechnical engineering , organic chemistry , thin film transistor
Arctic warming is expected to increase thermokarst erosion in thaw lakes, thus inducing large emissions of CH 4 to the atmosphere. To reduce uncertainties about the mechanisms, magnitude and timing of methane emissions, we conducted an in‐situ experiment to simulate lake expansion following thermokarst erosion. Three tundra horizons were excavated, incubated at the bottom of a thaw lake and subsequently monitored for CH 4 ebullition from mid‐season until lake freeze‐up. Although the permafrost and seasonally frozen active layer emitted little CH 4 throughout the experiment, ebullition from the thawed active layer began the first week, quickly reaching rates (39 mg CH 4 m −2 day −1 ) comparable to background ebullition in Siberian thaw lakes. While the long‐term fate of permafrost carbon from thermokarst lake expansion remains uncertain, the short‐term methane release is dominated by upper active layer carbon. Thus, deepening of the upper active layer in a thaw lake dominated landscape should increase CH 4 ebullition rates.