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Plant‐mediated methane emission from an Indian mangrove
Author(s) -
Purvaja Ramachandran,
Ramesh Ramachandran,
Frenzel Peter
Publication year - 2004
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2004.00834.x
Subject(s) - mangrove , avicennia marina , methane , aerial root , environmental science , avicennia , wetland , atmospheric methane , aerenchyma , monsoon , dry season , ecology , biology , oceanography , geology
Mangroves have been considered for a long time to be a minor methane source, but recent reports have shown that polluted mangroves may emit substantial amounts of methane. In an unpolluted Indian mangrove, we measured annual methane emission rates of 10 g CH 4 yr −1 from the stands of Avicennia marina . This rate is of the same order of magnitude as rates from Northern wetlands. Methane emission from a freshwater‐influenced area was higher, but was lower from a stunted mangrove growing on a hypersaline soil. Methane emission was mediated by the pneumatophores of Avicennia . This was consistent with the methane concentration in the aerenchyma, which decreased on average from 350 ppm v in the cable roots to 10 ppm v in the emergent part of the pneumatophores. However, the number of pneumatophores varied seasonally. The minimum number occurred during the monsoon season, which reduced methane emissions largely. Ebullition from unvegetated areas may also be important, at least during monsoon season when measured bubble fluxes were occasionally about five times as high as pneumatophore‐mediated emissions.