The concurrent short-term fluctuations of methane (CH₄) and carbon dioxide (CO₂) concentrations and emissions in lakes are not well studied. Quantifying the differences in daytime versus nighttime dynamics may provide information about the controls over greenhouse gas production and may have relevance to lake carbon budgets. In this study, the diel variation of CH₄ and CO₂ emissions and concentration patterns were determined along the water column of 2 temperate lakes with different trophic states during July 2015. The results showed that the shallow eutrophic lake had significantly higher CH₄ and CO₂ releases than the deep oligo-mesotrophic lake. No significant diel fluctuations were observed in atmospheric CH₄ emissions from either lake or in CO₂ emission from the oligo-mesotrophic lake, but significantly higher CO₂ emission from the eutrophic lake occurred during the daytime compared to nighttime. Based on a diffusion–reaction model, it was possible to estimate the diel variation of the sources and sinks of dissolved CH₄ throughout the water column, suggesting lateral transport is a potential source of CH₄ in oxygenated water layers in the oligo-mesotrophic lake. Sources and sinks throughout the water column should be considered in future studies for a better understanding of CH₄ dynamics within the lakes.

湖泊中甲烷（CH ₄）和二氧化碳（CO ₂）浓度和排放的短期短期波动并没有得到很好的研究。量化白天与夜间动态之间的差异可能会提供有关温室气体生产控制的信息，并且可能与湖泊碳预算有关。在这项研究中，确定了2015年7月沿两个营养状态不同的温带湖泊水柱CH ₄和CO ₂排放的迪尔变化和浓度模式。结果表明，浅水富营养化湖泊中CH ₄和CO明显更高₂比深层的中营养湖泊释放更多。湖泊中的大气CH ₄排放或中营养型湖泊的CO ₂排放均未观察到明显的狄尔波动，但与夜间相比，白天富营养化湖泊中的CO ₂排放显着更高。基于扩散反应模型，可以估算出整个水柱中溶解的CH ₄的源和汇的diel变化，这表明侧向输送是贫油-中营养湖泊中氧化水层中CH ₄的潜在来源。。在以后的研究中应考虑整个水柱中的水源和汇，以更好地了解CH ₄ 湖泊内的动态。