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Methane flux: Water table relations in northern wetlands
Author(s) -
Moore T. R.,
Roulet N. T.
Publication year - 1993
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 - 10.1029/93gl00208
Subject(s) - peat , water table , flux (metallurgy) , table (database) , environmental science , subarctic climate , hydrology (agriculture) , wetland , atmospheric sciences , atmosphere (unit) , boreal , soil water , temperate climate , drainage , soil science , groundwater , geology , chemistry , oceanography , ecology , meteorology , geography , geotechnical engineering , organic chemistry , computer science , data mining , biology , paleontology
Water table position, through the creation of aerobic and anaerobic conditions in the soil profile, plays an important role in controlling CH 4 flux from wetlands. A laboratory study of peat columns revealed that CH 4 emission rates initially increased and then decreased as the water table was lowered from the peat surface to a depth of 50 cm, with the release of CH 4 trapped in pores. There was a strong hysteresis between CH 4 flux on the falling and rising water table limbs (falling > rising). When expressed as seasonal average values, there was a strong relationship (r² 0.08 – 0.74) between log CH 4 flux and water table position for sites within 5 wetland regions in boreal‐subarctic Canada. The regression coefficients were similar among regions (0.022 – 0.037), but there were differences in the regression constants (0.47 – 1.89). CH 4 flux from drained, forested peatland soils decreased as the water table depth increased, and several sites were transformed from sources to sinks of CH 4 . Global CH 4 emissions to the atmosphere may have been reduced by ≈ 1 Tg yr −1 by peatland drainage during the last 100 yr.