School of Environment, Nanjing Normal University, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Jiangsu Key Laboratory of Environmental Change and Ecological Construction, Nanjing 210023, China.
School of Environment, Nanjing Normal University, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Jiangsu Key Laboratory of Environmental Change and Ecological Construction, Nanjing 210023, China.
Sci Total Environ. 2022 Feb 1;806(Pt 3):151260. doi: 10.1016/j.scitotenv.2021.151260. Epub 2021 Oct 27.
Sulfate (SO) concentrations in eutrophic lakes are continuously increasing; however, the effect of increasing SO concentrations on organic carbon mineralization, especially the greenhouse gas emissions of sediments, remains unclear. Here, we constructed a series of microcosms with initial SO concentrations of 0, 30, 60, 90, 120, 150, and 180 mg/L to study the effects of increased SO concentrations, coupled with cyanobacterial blooms, on organic carbon mineralization in Lake Taihu. Cyanobacterial blooms promoted sulfate reduction and released a large amount of inorganic carbon. The SO concentrations in cyanobacteria treatments significantly decreased and eventually reached close to 0. As the initial SO concentration increased, the sulfate reduction rates significantly increased, with maximum values of 9.39, 9.44, 28.02, 30.89, 39.68, and 54.28 mg/L∙d for 30, 60, 90, 120, 150, and 180 mg/L SO, respectively. The total organic carbon content in sediments (51.16-52.70 g/kg) decreased with the initial SO concentration (R = 0.97), and the total inorganic carbon content in overlying water (159.97-182.73 mg/L) showed the opposite pattern (R = 0.91). The initial SO concentration was positively correlated with carbon dioxide (CO) emissions (R = 0.68) and negatively correlated with methane (CH) emissions (R = 0.96). The highest CO concentration and lowest CH concentration in the 180 mg/L SO treatment were 1688.78 and 1903 μmol/L, respectively. These biogeochemical processes were related to competition for organic carbon sources between sulfate reduction bacteria (SRB) and methane production archaea (MPA) in sediments. The abundance of SRB was positively correlated with the initial SO concentration and ranged from 6.65 × 10 to 2.98 × 10 copies/g; the abundance of MPA showed the opposite pattern and ranged from 1.99 × 10 to 3.35 × 10copies/g. These findings enhance our understanding of the effect of increasing SO concentrations on organic carbon mineralization and could enhance the accuracy of assessments of greenhouse gas emissions in eutrophic lakes.
富营养化湖泊中的硫酸盐 (SO) 浓度不断增加；然而，不断增加的 SO 浓度对有机碳矿化的影响，特别是沉积物中温室气体的排放，仍不清楚。在这里，我们构建了一系列初始 SO 浓度为 0、30、60、90、120、150 和 180mg/L 的微宇宙，以研究增加的 SO 浓度与蓝藻水华相结合对太湖有机碳矿化的影响。蓝藻水华促进硫酸盐还原并释放大量无机碳。蓝藻处理中的 SO 浓度显著降低，最终接近 0。随着初始 SO 浓度的增加，硫酸盐还原速率显著增加，分别达到 9.39、9.44、28.02、30.89、39.68 和 54.28mg/L·d，SO 浓度分别为 30、60、90、120、150 和 180mg/L。沉积物中的总有机碳含量（51.16-52.70g/kg）随初始 SO 浓度降低（R=0.97），而上覆水中的总无机碳含量（159.97-182.73mg/L）呈相反模式（R=0.91）。初始 SO 浓度与二氧化碳（CO）排放呈正相关（R=0.68），与甲烷（CH）排放呈负相关（R=0.96）。在 180mg/L SO 处理中，CO 的最高浓度和 CH 的最低浓度分别为 1688.78 和 1903μmol/L。这些生物地球化学过程与硫酸盐还原菌（SRB）和沉积物中甲烷产生古菌（MPA）对有机碳源的竞争有关。SRB 的丰度与初始 SO 浓度呈正相关，范围为 6.65×10 至 2.98×10 拷贝/g；MPA 的丰度呈相反模式，范围为 1.99×10 至 3.35×10 拷贝/g。这些发现增强了我们对增加的 SO 浓度对有机碳矿化影响的理解，并可以提高对富营养化湖泊温室气体排放评估的准确性。
