National Research Council, Institute of Ecosystem Study, Largo Tonolli 50, 28922 Verbania Pallanza, Italy.
UFZ - Helmholtz Centre for Environmental Research, Department of Lake Research, Brückstr. 3a, D-39114 Magdeburg, Germany.
Sci Total Environ. 2017 Mar 1;581-582:10-18. doi: 10.1016/j.scitotenv.2017.01.004. Epub 2017 Jan 7.
Globally, reservoirs are a significant source of atmospheric CO. However, precise quantification of greenhouse gas emissions from drinking water reservoirs on the regional or national scale is still challenging. We calculated CO fluxes for 39 German drinking water reservoirs during a period of 22years (1991-2013) using routine monitoring data in order to quantify total emission of CO from drinking water reservoirs in Germany and to identify major drivers. All reservoirs were a net CO source with a median flux of 167gCmy, which makes gaseous emissions a relevant process for the carbon budget of each reservoir. Fluxes varied seasonally with median fluxes of 13, 48, and 201gCmy in spring, summer, and autumn respectively. Differences between reservoirs appeared to be primarily caused by the concentration of CO in the surface water rather than by the physical gas transfer coefficient. Consideration of short term fluctuations of the gas transfer coefficient due to varying wind speed had only a minor effect on the annual budgets. High CO emissions only occurred in reservoirs with pH<7 and total alkalinity <0.2mEql. Annual CO emissions correlated exponentially with pH but not with dissolved organic carbon (DOC). There was significant correlation between land use in the catchment and CO emissions. In total, German drinking water reservoirs emit 44000t of CO annually, which makes them a negligible CO source (<0.005% of national CO emissions) in Germany.
全球范围内，水库是大气 CO 的重要来源。然而，精确量化饮用水水库在区域或国家尺度上的温室气体排放仍然具有挑战性。我们使用常规监测数据，计算了 39 个德国饮用水水库在 22 年（1991-2013 年）期间的 CO 通量，以量化德国饮用水水库的 CO 总排放量，并确定主要驱动因素。所有水库均为 CO 净源，中值通量为 167gCmy，这使得气态排放成为每个水库碳预算的一个相关过程。通量随季节变化，春季、夏季和秋季的中值通量分别为 13、48 和 201gCmy。水库之间的差异似乎主要是由地表水的 CO 浓度引起的，而不是由物理气体转移系数引起的。由于风速变化导致气体转移系数的短期波动对年度预算的影响较小。仅在 pH<7 和总碱度 <0.2mEql 的水库中才会发生高 CO 排放。年 CO 排放量与 pH 呈指数相关，但与溶解有机碳（DOC）无关。集水区的土地利用与 CO 排放之间存在显著相关性。总的来说，德国饮用水水库每年排放 44000t 的 CO，这使得它们在德国 CO 排放中微不足道（<0.005%）。
