State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
Appl Microbiol Biotechnol. 2014 Feb;98(4):1817-29. doi: 10.1007/s00253-013-5104-6. Epub 2013 Aug 2.
Invasion by the exotic species Spartina alterniflora, which has high net primary productivity and superior reproductive capacity compared with native plants, has led to rapid organic carbon accumulation and increased methane (CH₄) emission in the coastal salt marsh of China. To elucidate the mechanisms underlying this effect, the methanogen community structure and CH₄ production potential as well as soil organic carbon (SOC), dissolved organic carbon, dissolved organic acids, methylated amines, aboveground biomass, and litter mass were measured during the invasion chronosequence (0-16 years). The CH₄ production potential in the S. alterniflora marsh (range, 2.94-3.95 μg kg(-1) day(-1)) was significantly higher than that in the bare tidal mudflat. CH₄ production potential correlated significantly with SOC, acetate, and trimethylamine concentrations in the 0-20 cm soil layer. The abundance of methanogenic archaea also correlated significantly with SOC, and the dominant species clearly varied with S. alterniflora-driven SOC accumulation. The acetotrophic Methanosaetaceae family members comprised a substantial proportion of the methanogenic archaea in the bare tidal mudflat while Methanosarcinaceae family members utilized methylated amines as substrates in the S. alterniflora marsh. Ordination analysis indicated that trimethylamine concentration was the primary factor inducing the shift in the methanogenic archaea composition, and regressive analysis indicated that the facultative family Methanosarcinaceae increased linearly with trimethylamine concentration in the increasingly sulfate-rich salt marsh. Our results indicate that increased CH₄ production during the S. alterniflora invasion chronosequence was due to increased levels of the non-competitive substrate trimethylamine and a shift in the methanogenic archaea community.
外来物种互花米草的入侵，与本地植物相比，它具有更高的净初级生产力和更强的繁殖能力，导致中国沿海盐沼中有机碳的快速积累和甲烷（CH₄）排放的增加。为了阐明这种效应的机制，在入侵时间序列（0-16 年）中，测量了产甲烷菌群落结构和 CH₄产生潜力以及土壤有机碳（SOC）、溶解有机碳、溶解有机酸、甲基化胺、地上生物量和凋落物质量。互花米草沼泽（范围为 2.94-3.95 μg kg(-1) day(-1))的 CH₄产生潜力明显高于裸潮滩。CH₄产生潜力与 0-20 cm 土壤层中的 SOC、乙酸和三甲胺浓度显著相关。产甲烷古菌的丰度也与 SOC 显著相关，优势种随着互花米草驱动的 SOC 积累而明显变化。在裸潮滩中，乙酸营养型 Methanosaetaceae 家族成员构成了产甲烷古菌的主要部分，而 Methanosarcinaceae 家族成员在互花米草沼泽中利用甲基化胺作为基质。排序分析表明，三甲胺浓度是导致产甲烷古菌组成发生变化的主要因素，回归分析表明，兼性家族 Methanosarcinaceae 随着硫酸盐含量越来越丰富的盐沼中三甲胺浓度的增加呈线性增加。我们的结果表明，互花米草入侵时间序列中 CH₄产生的增加是由于非竞争基质三甲胺水平的增加和产甲烷古菌群落的变化所致。
