Yuan Junji, Ding Weixin, Liu Deyan, Kang Hojeong, Xiang Jian, Lin Yongxin
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.
Sci Rep. 2016 Jan 5;6:18777. doi: 10.1038/srep18777.
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.
互花米草入侵中国沿海地区增加了甲烷（CH₄）排放。为阐明其潜在机制，我们沿着一个沿海湿地样带测量了CH₄产生潜力、产甲烷菌群落结构和生物地球化学因子，该样带由五个栖息地区域组成：开阔水域、光滩潮间带、互花米草入侵沼泽以及本地的盐地碱蓬和芦苇沼泽。互花米草沼泽中的CH₄产生潜力比其他区域高10倍，且与土壤有机碳、溶解有机碳和三甲胺浓度显著相关，但与乙酸盐或甲酸盐浓度无关。尽管互花米草沼泽中产甲烷菌的多样性最低，但与本地的盐地碱蓬和芦苇沼泽相比，入侵使产甲烷菌丰度增加了3.48倍，这是由于兼性甲烷八叠球菌科增加而非乙酸营养型和氢营养型产甲烷菌增加所致。排序分析表明，三甲胺是调节产甲烷菌群落结构变化的主要因素。添加三甲胺使CH₄产生速率提高了1255倍，但乙酸盐和H₂/CO₂的产生速率仅分别提高了5.61倍和11.4倍。互花米草入侵提高了非竞争性三甲胺的浓度，并使产甲烷菌群落从乙酸营养型转变为兼性产甲烷菌，这共同促进了CH₄产生潜力的增加。
