Ruff S Emil, Biddle Jennifer F, Teske Andreas P, Knittel Katrin, Boetius Antje, Ramette Alban
HGF MPG Group for Deep Sea Ecology and Technology and Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, D-28359 Bremen, Germany;
College of Earth, Ocean and Environment, University of Delaware, Lewes, DE 19958;
Proc Natl Acad Sci U S A. 2015 Mar 31;112(13):4015-20. doi: 10.1073/pnas.1421865112. Epub 2015 Mar 16.
Methane seeps are widespread seafloor ecosystems shaped by the emission of gas from seabed reservoirs. The microorganisms inhabiting methane seeps transform the chemical energy in methane to products that sustain rich benthic communities around the gas leaks. Despite the biogeochemical relevance of microbial methane removal at seeps, the global diversity and dispersion of seep microbiota remain unknown. Here we determined the microbial diversity and community structure of 23 globally distributed methane seeps and compared these to the microbial communities of 54 other seafloor ecosystems, including sulfate-methane transition zones, hydrothermal vents, coastal sediments, and deep-sea surface and subsurface sediments. We found that methane seep communities show moderate levels of microbial richness compared with other seafloor ecosystems and harbor distinct bacterial and archaeal taxa with cosmopolitan distribution and key biogeochemical functions. The high relative sequence abundance of ANME (anaerobic methanotrophic archaea), as well as aerobic Methylococcales, sulfate-reducing Desulfobacterales, and sulfide-oxidizing Thiotrichales, matches the most favorable microbial metabolisms at methane seeps in terms of substrate supply and distinguishes the seep microbiome from other seafloor microbiomes. The key functional taxa varied in relative sequence abundance between different seeps due to the environmental factors, sediment depth and seafloor temperature. The degree of endemism of the methane seep microbiome suggests a high local diversification in these heterogeneous but long-lived ecosystems. Our results indicate that the seep microbiome is structured according to metacommunity processes and that few cosmopolitan microbial taxa mediate the bulk of methane oxidation, with global relevance to methane emission in the ocean.
甲烷渗漏是由海底储层排放气体形成的广泛分布的海底生态系统。栖息在甲烷渗漏处的微生物将甲烷中的化学能转化为维持气体渗漏周围丰富底栖生物群落的产物。尽管微生物在渗漏处去除甲烷具有生物地球化学意义，但渗漏微生物群的全球多样性和分布情况仍不清楚。在这里，我们确定了全球分布的23个甲烷渗漏处的微生物多样性和群落结构，并将其与其他54个海底生态系统的微生物群落进行了比较，这些生态系统包括硫酸盐 - 甲烷过渡带、热液喷口、海岸沉积物以及深海表层和次表层沉积物。我们发现，与其他海底生态系统相比，甲烷渗漏群落的微生物丰富度处于中等水平，并且拥有具有全球分布和关键生物地球化学功能的独特细菌和古菌类群。厌氧甲烷氧化古菌（ANME）以及需氧甲基球菌目、硫酸盐还原脱硫杆菌目和硫化物氧化硫发菌目的相对序列丰度较高，这与甲烷渗漏处最有利的微生物代谢在底物供应方面相匹配，并将渗漏微生物群落与其他海底微生物群落区分开来。由于环境因素、沉积物深度和海底温度的影响，不同渗漏处关键功能类群的相对序列丰度有所不同。甲烷渗漏微生物群落的特有程度表明，在这些异质但长期存在的生态系统中存在高度的局部分化。我们的结果表明，渗漏微生物群落是根据集合群落过程构建的，并且少数全球分布的微生物类群介导了大部分甲烷氧化，这对海洋中的甲烷排放具有全球意义。
