Wen Cheng-Cheng, Huang Ting-Lin, Kong Chang-Hao, Zhang Zhi-Gang, Tian Peng-Fei
Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Huan Jing Ke Xue. 2023 Mar 8;44(3):1452-1464. doi: 10.13227/j.hjkx.202205012.
Seasonal algal blooms produce a high risk for water supply safety. To explore the mechanism of seasonal algal blooms in northern eutrophic stratified reservoirs, the combination of taxonomic and functional classifications, local weighted regression (LOWESS), and Boundary line analysis (BLA) were employed to obtain the succession features and environmental thresholds of seasonal (e.g., spring and summer) algal blooms, based on the long-term and high-frequency monitoring from 2017 to 2020 in Lijiahe Reservoir. The results showed that:① the succession and response mechanisms of algal blooms were different in spring and summer. In detail, Chlorophyta, Bacillariophyta, and Dinoflagellates (e.g., low-temperature, small, high surface-to-volume genera) dominated in spring, whereas Chlorophyta, Bacillariophyta, and Cyanobacteria (e.g., high-temperature, large or colonial, low surface-to-volume genera) dominated in summer. The differences in physiological and morphological characteristics of algae were the internal cause triggering seasonal algal blooms. ② The main drivers of algal blooms were different in spring and summer. Spring blooms were controlled by water temperature (WT), mixing depth (i.e., ), and light availability (i.e., /), whereas summer blooms were jointly influenced by WT, , /, and total phosphorus (TP). The differences in the changes of the major drivers were external causes triggering seasonal algal blooms. ③ The water environment thresholds starting seasonal algal blooms were different in spring and summer. The thresholds of WT, , and / in spring were>9.4℃, <10.9 m, and>0.24, respectively, whereas the thresholds of WT, , /, and TP in summer were>16.0℃, <11.6 m, >0.16, and>0.011 mg·L, respectively. Based on the research on the mechanism of seasonal algal blooms and related thresholds, this work will provide a reference for the control of subsequent algal blooms.
季节性藻类大量繁殖给水供应安全带来了高风险。为探究北方富营养化分层水库季节性藻类大量繁殖的机制，基于2017年至2020年对李家河水库的长期高频监测，采用分类学和功能分类相结合、局部加权回归（LOWESS）和边界线分析（BLA）来获取季节性（如春季和夏季）藻类大量繁殖的演替特征和环境阈值。结果表明：①春季和夏季藻类大量繁殖的演替和响应机制不同。具体而言，绿藻门、硅藻门和甲藻（如低温、小型、高表面积体积比的属）在春季占主导，而绿藻门、硅藻门和蓝藻门（如高温、大型或群体、低表面积体积比的属）在夏季占主导。藻类生理和形态特征的差异是引发季节性藻类大量繁殖的内在原因。②春季和夏季藻类大量繁殖的主要驱动因素不同。春季藻类大量繁殖受水温（WT）、混合深度（即 ）和光照可用性（即 /）控制，而夏季藻类大量繁殖受WT、 、 /和总磷（TP）共同影响。主要驱动因素变化的差异是引发季节性藻类大量繁殖的外在原因。③春季和夏季开始季节性藻类大量繁殖的水环境阈值不同。春季WT、 和 /的阈值分别>9.4℃、<10.9 m和>0.24，而夏季WT、 、 /和TP的阈值分别>16.0℃、<11.6 m、>0.16和>0.011 mg·L。基于对季节性藻类大量繁殖机制及相关阈值 的研究，这项工作将为后续藻类大量繁殖的控制提供参考。
