Groupe de Recherche Interuniversitaire en Limnologie, Département des Sciences Biologiques, Université du Québec à Montréal, Case Postale 8888, Succursale Centre-Ville, Montréal, Quebec, Canada H3C 3P8.
Nat Commun. 2014 Oct 30;5:5350. doi: 10.1038/ncomms6350.
Methanogenesis has traditionally been assumed to occur only in anoxic environments, yet there is mounting, albeit indirect, evidence of methane (CH4) production in oxic marine and freshwaters. Here we present the first direct, ecosystem-scale demonstration of methanogenesis in oxic lake waters. This methanogenesis appears to be driven by acetoclastic production, and is closely linked to algal dynamics. We show that oxic water methanogenesis is a significant component of the overall CH4 budget in a small, shallow lake, and provide evidence that this pathway may be the main CH4 source in large, deep lakes and open oceans. Our results challenge the current global understanding of aquatic CH4 dynamics, and suggest a hitherto unestablished link between pelagic CH4 emissions and surface-water primary production. This link may be particularly sensitive to widespread and increasing human influences on aquatic ecosystem primary productivity.
产甲烷作用传统上被认为仅发生在缺氧环境中，但越来越多的间接证据表明，在好氧海洋和淡水环境中也会产生甲烷（CH4）。在这里，我们首次直接在好氧湖泊水中证明了产甲烷作用的存在。这种产甲烷作用似乎是由乙酸营养型产生驱动的，并且与藻类动态密切相关。我们表明，好氧水的产甲烷作用是小型浅水湖中总 CH4 预算的重要组成部分，并提供了证据表明，这种途径可能是大型深湖和开阔海洋中 CH4 的主要来源。我们的研究结果对当前全球对水生 CH4 动力学的理解提出了挑战，并表明在海洋 CH4 排放和地表水初级生产力之间存在迄今尚未建立的联系。这种联系可能对广泛而不断增加的人类对水生生态系统初级生产力的影响特别敏感。
