title: Shifts in methanogen community structure and function across a coastal marsh transect: effects of exotic Spartina alterniflora invasion.
abstract: Invasion of Spartina alterniflora in coastal areas of China increased methane (CH4) emissions. To elucidate the underlying mechanisms, we measured CH4 production potential, methanogen community structure and biogeochemical factors along a coastal wetland transect comprised of five habitat regions: open water, bare tidal flat, invasive S. alterniflora marsh and native Suaeda salsa and Phragmites australis marshes. CH4 production potential in S. alterniflora marsh was 10 times higher than that in other regions, and it was significantly correlated with soil organic carbon, dissolved organic carbon and trimethylamine concentrations, but was not correlated with acetate or formate concentrations. Although the diversity of methanogens was lowest in S. alterniflora marsh, invasion increased methanogen abundance by 3.48-fold, compared with native S. salsa and P. australis marshes due to increase of facultative Methanosarcinaceae rather than acetotrophic and hydrogenotrophic methanogens. Ordination analyses suggested that trimethylamine was the primary factor regulating shift in methanogen community structure. Addition of trimethylamine increased CH4 production rates by 1255-fold but only by 5.61- and 11.4-fold for acetate and H2/CO2, respectively. S. alterniflora invasion elevated concentration of non-competitive trimethylamine, and shifted methanogen community from acetotrophic to facultative methanogens, which together facilitated increased CH4 production potential.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.|University of Chinese Academy of Sciences, Beijing 10049, China.
authors.forename: Junji
authors.initials: J
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Weixin
authors.initials: W
authors.lastname: Ding
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Deyan
authors.initials: D
authors.lastname: Liu
authors.affiliation: School of Civil and Environmental Engineering, Yonsei University, Seoul 120-749, Korea.
authors.forename: Hojeong
authors.initials: H
authors.lastname: Kang
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.|University of Chinese Academy of Sciences, Beijing 10049, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Xiang
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.|University of Chinese Academy of Sciences, Beijing 10049, China.
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Lin
mesh_terms: D044822:Biodiversity; D018533:Biomass; D017753:Ecosystem; D004777:Environment; D058865:Introduced Species; D008697:Methane / Q000032:analysis*; D010944:Plants; D006109:Poaceae / Q000235:genetics / Q000378:metabolism; D012987:Soil
chemical_list: D012987:Soil; D008697:Methane