Lakes and reservoirs globally produce large quantities of methane and carbon dioxide in their sediments, which accumulate in the hypolimnia (bottom waters) during thermally stratified conditions. A key parameter controlling hypolimnetic greenhouse gas concentrations is dissolved oxygen. Land use and climate change have increased hypolimnetic anoxia worldwide in lakes and reservoirs, which is expected to affect their methane and carbon dioxide concentrations. We conducted whole‐ecosystem oxygenation experiments to assess the effects of oxygen concentrations on dissolved hypolimnetic greenhouse gas concentrations in comparison to a reference reservoir and calculated the maximum hypolimnetic global warming potential in both reservoirs over three summers. We observed significantly greater hypolimnetic methane under anoxic conditions but similar carbon dioxide concentrations, leading to greater hypolimnetic global warming potential of anoxic hypolimnia. Our study indicates that the global warming potential of hypolimnetic greenhouse gas concentrations may increase as the prevalence of hypolimnetic anoxia increases due to global change.

中文翻译：

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整个生态系统的氧合作用实验显示，缺氧期间储层中的次低层甲烷浓度大大提高

全球的湖泊和水库在沉积物中会产生大量的甲烷和二氧化碳，这些沉积物在热分层条件下会积聚在低渗（底水）中。控制低温室气体浓度的关键参数是溶解氧。全世界的湖泊和水库中，土地利用和气候变化加剧了低铁性缺氧，预计将影响其甲烷和二氧化碳浓度。我们进行了整个生态系统的充氧实验，以评估氧气浓度对参比储层的溶解低速温室气体浓度的影响，并计算了三个夏季两个储层中最大的低速全球变暖潜能。我们观察到缺氧条件下的低通气甲烷明显增加，但二氧化碳浓度相似，导致缺氧性低通气的低通气性全球变暖潜力更大。我们的研究表明，由于全球变化引起的低氧性缺氧的发生率增加，低碳温室气体浓度的全球变暖潜力可能会增加。