Substrate sources regulate spatial variation of metabolically active methanogens from two contrasting freshwater wetlands
Substrate sources regulate spatial variation of metabolically active methanogens from two contrasting freshwater wetlands
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DOI：
10.1007/s00253-015-6912-7
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发表时间：
2015-08
影响因子：
5
通讯作者：
Yongxin Lin;Deyan Liu;W. Ding;Hojeong Kang;C. Freeman;Junji Yuan;Jian Xiang
中科院分区：
文献类型：
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作者：
Yongxin Lin;Deyan Liu;W. Ding;Hojeong Kang;C. Freeman;Junji Yuan;Jian Xiang
有充分证据表明，自然湿地的甲烷 (CH4) 排放在现场尺度上表现出巨大的空间变化。然而，人们对介导这些差异的代谢活性产甲烷菌知之甚少。我们探索了中国三江平原夏季淹没的低 CH4 排放的小叶茅草沼泽和永久淹没的高 CH4 排放的苔草沼泽中活性产甲烷菌的空间格局。因C.狭叶沼泽中,13C-乙酸盐的添加显着提高了CH4的产率,并且发现甲烷八叠球菌科产甲烷菌参与了乙酸盐的消耗。因C. lasiocarpamarsh，CH 4 生产率没有明显增加，并且没有产甲烷菌物种被13 C标记。然而，当添加 13 CO 2 -H 2 时，发现CH 4 的产生是由于C中的Fen簇（甲烷微生物目）。狭叶沼泽和甲烷杆菌簇 B (Methanobacteriaceae) 以及芬簇 C.拉西奥卡帕沼泽。这些结果表明，CH4 主要由氢营养型产甲烷菌使用主要源自 C 植物凋落物的底物产生。 lasiocarpamarsh 以及氢营养型和乙酰分解型产甲烷菌使用主要源自 C 根分泌物的底物。狭叶沼泽。在 C 中原位测量的 CH4 排放量显着降低。 angustifoliamarsh 与 C 相比主要是由于底物的缺乏。拉西奥卡帕沼泽。因此，我们推测底物源调节活性产甲烷菌的类型和 CH4 生产途径，从而导致在这些淡水沼泽中观察到的 CH4 生产的空间变化。
There is ample evidence that methane (CH4) emissions from natural wetlands exhibit large spatial variations at a field scale. However, little is known about the metabolically active methanogens mediating these differences. We explored the spatial patterns in active methanogens of summer inundatedCalamagrostis angustifoliamarsh with low CH4emissions and permanently inundatedCarex lasiocarpamarsh with high CH4emissions in Sanjiang Plain, China. InC. angustifoliamarsh, the addition of13C-acetate significantly increased the CH4production rate, andMethanosarcinaceaemethanogens were found to participate in the consumption of acetate. InC. lasiocarpamarsh, there was no apparent increase in the CH4production rate and no methanogen species were labeled with13C. When13CO2-H2was added, however, CH4production was found to be due to Fen Cluster (Methanomicrobiales) inC. angustifoliamarsh andMethanobacteriumCluster B (Methanobacteriaceae) together with Fen Cluster inC. lasiocarpamarsh. These results suggested that CH4was produced primarily by hydrogenotrophic methanogens using substrates mainly derived from plant litter inC. lasiocarpamarsh and by both hydrogenotrophic and acetoclastic methanogens using substrates mainly derived from root exudate inC. angustifoliamarsh. The significantly lower CH4emissions measured in situ inC. angustifoliamarsh was primarily due to a deficiency of substrates compared toC. lasiocarpamarsh. Therefore, we speculate that the substrate source regulates both the type of active methanogens and the CH4production pathway and consequently contributes to the spatial variations in CH4productions observed in these freshwater marshes.