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Surface deformations as indicators of deep ebullition fluxes in a large northern peatland
Author(s) -
Glaser P. H.,
Chanton J. P.,
Morin P.,
Rosenberry D. O.,
Siegel D. I.,
Ruud O.,
Chasar L. I.,
Reeve A. S.
Publication year - 2004
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2003gb002069
Subject(s) - peat , bog , radiocarbon dating , geology , precipitation , methane , environmental science , plateau (mathematics) , atmospheric sciences , hydrology (agriculture) , physical geography , paleontology , meteorology , ecology , geotechnical engineering , geography , biology , mathematical analysis , physics , mathematics
Peatlands deform elastically during precipitation cycles by small (±3 cm) oscillations in surface elevation. In contrast, we used a Global Positioning System network to measure larger oscillations that exceeded 20 cm over periods of 4–12 hours during two seasonal droughts at a bog and fen site in northern Minnesota. The second summer drought also triggered 19 depressuring cycles in an overpressured stratum under the bog site. The synchronicity between the largest surface deformations and the depressuring cycles indicates that both phenomena are produced by the episodic release of large volumes of gas from deep semi‐elastic compartments confined by dense wood layers. We calculate that the three largest surface deformations were associated with the release of 136 g CH 4 m −2 , which exceeds by an order of magnitude the annual average chamber fluxes measured at this site. Ebullition of gas from the deep peat may therefore be a large and previously unrecognized source of radiocarbon depleted methane emissions from northern peatlands.