School of Environment, Nanjing Normal University, Nanjing 210023, PR China.
School of Environment, Nanjing Normal University, Nanjing 210023, PR China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, PR China; Jiangsu Key Laboratory of Environmental Change and Ecological Construction, Nanjing 210023, PR China; Jiangsu Engineering Laboratory of Water and Soil Eco-remediation, Nanjing 210023, PR China.
Sci Total Environ. 2019 Feb 15;651(Pt 1):466-474. doi: 10.1016/j.scitotenv.2018.09.197. Epub 2018 Sep 17.
Lakes are regarded as one of the important sources of atmospheric CH. However, the role of cyanobacteria blooms (CBBs) play in the CH production in eutrophic lakes is not fully clear. In this study, the spatial distribution characteristics of CH concentrations in surface water and sediment columns were investigated in Zhushan Bay of Taihu lake, China. Results showed that CH concentrations in CBBs accumulated zones were much higher than that in the open lake areas, with the highest values of 3.79 μmol·L and 2261.88 μmol·L in surface water and sediment columns, respectively. CH concentrations were strongly influenced by various factors. In surface water, the occurrence of CBBs greatly contributed to CH productions, as evidenced by the well-predicting for CH concentrations using Chl-a and NH concentrations. In the sediments, the Ignition Loss and C:N ratio values were two indicators of CH contents, suggesting that the methanogenesis processes were influenced by not only the quantities, but also the qualities of organic matter. The labile substrates produced during the CBBs decomposition processes promoted the CH production and migration from sediments to the water column, resulting in the coherence in CH concentrations between the sediments and the surface water. The high-resolution determinations of CH concentrations in surface water and sediments clarified that the CBBs were a neglected facilitator of CH productions, which should be considered in the future estimation of CH emissions in eutrophic lakes.
湖泊被认为是大气 CH 的重要来源之一。然而，富营养化湖泊中蓝藻水华（CBBs）在 CH 产生中的作用尚不完全清楚。本研究调查了中国太湖竺山湾表层水和沉积物柱中 CH 浓度的空间分布特征。结果表明，CBBs 积聚区的 CH 浓度明显高于开阔湖区，表层水和沉积物柱中的最高值分别为 3.79 μmol·L 和 2261.88 μmol·L。CH 浓度受多种因素的强烈影响。在表层水中，CBBs 的出现极大地促进了 CH 的产生，这可以通过 Chl-a 和 NH 浓度很好地预测 CH 浓度来证明。在沉积物中，Ignition Loss 和 C:N 比值是 CH 含量的两个指标，表明产甲烷过程不仅受有机质数量的影响，还受有机质质量的影响。CBBs 分解过程中产生的易分解底物促进了 CH 的产生和从沉积物向水柱的迁移，导致沉积物和表层水之间 CH 浓度的一致性。对表层水和沉积物中 CH 浓度的高分辨率测定表明，CBBs 是 CH 产生的一个被忽视的促进因素，在未来对富营养化湖泊 CH 排放的估计中应予以考虑。
