Open AccessMethane emission from Yangtze estuarine wetland, China
Author(s) -
Wang Dongqi,
Chen Zhenlou,
Xu Shiyuan
Publication year - 2009
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2008jg000857
Subject(s) - environmental science , wetland , estuary , flux (metallurgy) , environmental chemistry , atmospheric sciences , ecosystem , hydrology (agriculture) , chemistry , ecology , biology , geology , geotechnical engineering , organic chemistry
Yangtze estuary, lying in the subtropical monsoon region of China, is characterized by a unique environmental setting and endemic wetland plant species ( Scirpus mariqueter ). Methane (CH 4 ) emission fluxes were measured at the Yangtze estuarine wetland, Chongming Dongtan (CD), by a static closed chamber technique from May 2004 to April 2005. The results showed that CD is the source of atmospheric CH 4 , and emission fluxes had significant diurnal and seasonal variation. The annual average CH 4 emission flux was 2.06 mg m −2 h −1 at the CD marsh site and 0.04 mg m −2 h −1 at the CD bare tidal flat (nonvegetated). Wetland plant species ( S. mariqueter ) and temperature were the primary factors controlling the CH 4 emission. The results of the light and dark chamber comparison and plant shoot clipping experiment suggest that molecular diffusion and convective gas flow methods were the two main mechanisms of CH 4 transported via S. mariqueter plants in July. However, molecular diffusion was believed to be the primary transport mechanism from August to October, with leaf resistance as one of the factors regulating CH 4 diffusion. There was significant correlation between CH 4 fluxes and temperature, especially the 10 cm depth ground temperature ( R 2 = 0.7784). Although sediment organic carbon content did not determine CH 4 fluxes, net ecosystem production was significantly correlated with CH 4 fluxes, suggesting that the photosynthates of S. mariqueter effectively provided the substrate for methanogenic bacteria.