Sorbonne Université, UMR 7619 METIS, 4 place Jussieu, Box 105, 75005, Paris, France.
School of Environment, Nanjing Normal University, Nanjing, 210023, People's Republic of China.
Environ Sci Pollut Res Int. 2021 Mar;28(9):10967-10976. doi: 10.1007/s11356-020-11374-y. Epub 2020 Oct 26.
Inland freshwater lakes have been widely considered as significant sources of CO to the atmosphere. However, long-term measurements of CO dynamics in lakes are still lacking, but are necessary due to their large temporal variations. Herein, we present the long-term dynamics of water parameters in Lake Donghu from 2002 to 2016, and further calculate the partial pressure of CO (pCO) based on the measurements of pH, water temperature, and alkalinity from 2008 to 2016. The results revealed that a significantly high pCO occurred during the winter in Lake Donghu (p < 0.01), whereas no significant spatial difference was observed (p = 0.37). Statistical analysis indicated that the pCO in the lake was only positively correlated with the total phosphorus (TP) concentration (p < 0.05). A multilinear regression model provided the best predictors for the pCO; however, it only explained 16% of the observed pCO variability. This indicates the complex factors that influenced the pCO in Lake Donghu between 2008 and 2016. Our estimated CO flux revealed that Lake Donghu acted as a small CO source to the atmosphere during this period, with a mean CO flux of 10.8 ± 37.4 mg m day corresponding to a mean CO emission of 0.13 ± 0.43 Gg year. The CO emission fluxes in Lake Donghu were much lower than the mean CO fluxes reported for other lakes in China and globally. Furthermore, the long-term evolution of the CO flux indicated that Lake Donghu has shifted between acting as a CO source and sink, which highlights the need for long-term monitoring to accurately evaluate CO emissions from lakes.
内陆淡水湖泊被广泛认为是大气中 CO 的重要来源。然而，由于湖泊 CO 动态具有较大的时间变化，因此长期测量湖泊 CO 动态仍然缺乏，但这是必要的。在此，我们展示了 2002 年至 2016 年东湖的长期水参数动态，并进一步根据 2008 年至 2016 年 pH、水温、碱度的测量值计算了 CO 的分压（pCO）。结果表明，东湖冬季的 pCO 显著升高（p < 0.01），而没有观察到显著的空间差异（p = 0.37）。统计分析表明，湖泊中的 pCO 仅与总磷（TP）浓度呈正相关（p < 0.05）。多元线性回归模型为 pCO 提供了最佳预测因子，但仅解释了 16%的观测到的 pCO 变异性。这表明在 2008 年至 2016 年期间，影响东湖 pCO 的因素较为复杂。我们估算的 CO 通量表明，在此期间，东湖作为大气的 CO 小源，平均 CO 通量为 10.8 ± 37.4 mg m-2 d-1，对应于平均 CO 排放量为 0.13 ± 0.43 Gg year-1。东湖的 CO 排放通量远低于中国和全球其他湖泊报告的平均 CO 通量。此外，CO 通量的长期演变表明，东湖在作为 CO 源和汇之间发生了转变，这强调了需要进行长期监测以准确评估湖泊的 CO 排放。
