Microbial methane production in oxygenated water column of an oligotrophic lake
Microbial methane production in oxygenated water column of an oligotrophic lake
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DOI：
10.1073/pnas.1110716108
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发表时间：
2011-12-06
影响因子：
11.1
通讯作者：
Tang, Kam W.
中科院分区：
文献类型：
--
作者：
Grossart, Hans-Peter;Frindte, Katharina;Tang, Kam W.
水生科学的流行范式是微生物产甲烷主要发生在缺氧环境中。在这里，我们使用多种互补方法来证明微生物甲烷的产生可以而且确实发生在寡营养湖（德国施特林湖）的氧合良好的水柱中。在氧合良好的水柱上部 10 m 处反复记录到甲烷过饱和，并且甲烷最大值与 6 m 处的氧过饱和一致。未经处理的表湖湖水的实验室培养和用湖富集培养物接种光合自养生物，即使在有氧存在的情况下也能产生甲烷，并且其生产不受添加无机磷酸盐或甲基化化合物的影响。通过湖水的湖内孵化也检测到了甲烷的产生，在6 m处的最高产生率为1.8-2.4 nM.h(-1)，这可以解释当月观测到的环境甲烷积累的33-44%。现场和实验室测量支持甲烷生成和甲烷氧化之间的时间和空间解耦，这也有助于解释上部水柱中甲烷的过饱和。在含氧、富含甲烷的表层层中原位检测到潜在产甲烷古细菌，它们附着在光合自养生物上可能允许厌氧生长和直接转移用于产生甲烷的底物。对甲基辅酶 M 还原酶 A 基因 mRNA 的特异性 PCR 显示活跃的产甲烷作用。含氧水中微生物甲烷的产生是迄今为止被忽视的甲烷来源，并且对于水生环境中的碳循环和水到空气的甲烷通量非常重要。
The prevailing paradigm in aquatic science is that microbial methanogenesis happens primarily in anoxic environments. Here, we used multiple complementary approaches to show that microbial methane production could and did occur in the well-oxygenated water column of an oligotrophic lake (Lake Stechlin, Germany). Oversaturation of methane was repeatedly recorded in the well-oxygenated upper 10 m of the water column, and the methane maxima coincided with oxygen oversaturation at 6 m. Laboratory incubations of unamended epilimnetic lake water and inoculations of photoautotrophs with a lake-enrichment culture both led to methane production even in the presence of oxygen, and the production was not affected by the addition of inorganic phosphate or methylated compounds. Methane production was also detected by in-lake incubations of lake water, and the highest production rate was 1.8-2.4 nM.h(-1) at 6 m, which could explain 33-44% of the observed ambient methane accumulation in the same month. Temporal and spatial uncoupling between methanogenesis and methanotrophy was supported by field and laboratory measurements, which also helped explain the oversaturation of methane in the upper water column. Potentially methanogenic Archaea were detected in situ in the oxygenated, methane-rich epilimnion, and their attachment to photoautotrophs might allow for anaerobic growth and direct transfer of substrates for methane production. Specific PCR on mRNA of the methyl coenzyme M reductase A gene revealed active methanogenesis. Microbial methane production in oxygenated water represents a hitherto overlooked source of methane and can be important for carbon cycling in the aquatic environments and water to air methane flux.