Growth and population dynamics of anaerobic methane-oxidizing archaea and sulfate-reducing bacteria in a continuous-flow bioreactor
Growth and population dynamics of anaerobic methane-oxidizing archaea and sulfate-reducing bacteria in a continuous-flow bioreactor
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DOI：
10.1128/aem.71.7.3725-3733.2005
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发表时间：
2005-07-01
影响因子：
4.4
通讯作者：
DeLong, EF
中科院分区：
文献类型：
--
作者：
Girguis, PR;Cozen, AE;DeLong, EF
缺氧海洋沉积物中甲烷的消耗是由两个古细菌群（ANME-1和ANME-2）介导的生物地球化学现象，它们与硫酸盐还原菌共生存在。这些厌氧甲烷氧化菌尚未在纯培养中恢复，其生态学和生理学的关键方面仍然知之甚少。为了表征这些厌氧甲烷氧化菌和合养硫酸盐还原菌的生长和生理特征，我们在两个不同平流孔隙水流速的实验中，使用缺氧、连续的生物反应器培养海洋沉积物。我们使用定量PCR作为细胞计数的代理来检测厌氧甲烷氧化菌和脱硫类硫酸盐还原菌的生长动力学，并使用膜入口质谱法测量甲烷氧化速率。我们的数据表明，ANME-1和ANME-2古菌的特定生长速率对孔隙水How率的响应不同。ANME-2型甲烷氧化菌在低流量工况下的产率最高(mu（ANME-2) 0.167中心点周（-1）），而ANME-1型甲烷氧化菌在高流量工况下的产率最高(mu（ANME-1) = 0.218中心点周（-1））。在两种培养条件下，类似于desulfosarcina的硫酸盐还原细菌的生长速率约为0.3中心点周（-1），它们的生长动态表明硫酸盐还原细菌的生长可能受到厌氧甲烷营养菌群的促进，但不依赖于厌氧甲烷营养菌群。ANME-1的生长速率证实了实地观察，即ANME-1古菌在高流量条件下繁殖旺盛。我们的生长和甲烷氧化速率共同表明，厌氧甲烷氧化菌能够在这些实验中使用的一系列环境条件下实现大幅增长，包括相对较低的甲烷分压。
The consumption of methane in anoxic marine sediments is a biogeochemical phenomenon mediated by two archaeal groups (ANME-1 and ANME-2) that exist syntrophically with sulfate-reducing bacteria. These anaerobic methanotrophs have yet to be recovered in pure culture, and key aspects of their ecology and physiology remain poorly understood. To characterize the growth and physiology of these anaerobic methanotrophs and the syntrophic sulfate-reducing bacteria, we incubated marine sediments using an anoxic, continuous-How bioreactor during two experiments at different advective porewater flow rates. We examined the growth kinetics of anaerobic methanotrophs and Desulfosarcina-like sulfate-reducing bacteria using quantitative PCR as a proxy for cell counts, and measured methane oxidation rates using membrane-inlet mass spectrometry. Our data show that the specific growth rates of ANME-1 and ANME-2 archaea differed in response to porewater How rates. ANME-2 methanotrophs had the highest rates in lower-flow regimes (mu(ANME-2) 0.167 center dot week(-1)), whereas ANME-1 methanotrophs had the highest rates in higher-flow regimes (mu(ANME-1) = 0.218 center dot week(-1)). In both incubations, Desulfosarcina-like sulfate-reducing bacterial growth rates were approximately 0.3 center dot week(-1), and their growth dynamics suggested that sulfate-reducing bacterial growth might be facilitated by, but not dependent upon, an established anaerobic methanotrophic population. ANME-1 growth rates corroborate field observations that ANME-1 archaea flourish in higher-flow regimes. Our growth and methane oxidation rates jointly demonstrate that anaerobic methanotrophs are capable of attaining substantial growth over a range of environmental conditions used in these experiments, including relatively low methane partial pressures.