Li Yuyu, Zhang Songhe, Wanyan Jianfei, Song Yingying, Guo Shaozhuang, Lv Xin, Zhang Shuyou, Guo Hongyu, Xu Junsong
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China.
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China.
Sci Total Environ. 2025 Aug 20;998:180287. doi: 10.1016/j.scitotenv.2025.180287.
Algal bloom is one of the major current problems, while the impacts of algal bloom on the planktonic microbial community remain unclear. This study investigated the nutrients in water quality and surface sediment, and planktonic microbial community in twelve sampling sites from the western, eastern, northern, and center areas of Lake Taihu during the algal bloom period. We found that the mean total nitrogen, ammonium nitrogen, Chlorophyll(a) and chemical oxygen demand concentrations in overlying water varied significantly (p < 0.05) among four areas. The alpha diversity index of both bacterial and micro-eukaryotic communities was the highest in eastern Lake, and species turnover was important in compositional dissimilarity of the planktonic microbial community. Five algal bloom (ABM) and five non-algal bloom sites (UABM) were according to nutrients, Chlorophyll(a), and principal coordinate analysis results. The null model revealed that stochastic processes other than deterministic processes played a greater role, while decreased dispersal limitation and increased heterogeneous selection were observed in the microbial community within ABM compared to UABM. Network analyses revealed that algal blooms destabilized planktonic microbial food web by disrupting interactions among phytoplankton, protozoa, metazoans, and bacteria. Partial least squares path modeling analysis showed that sediment nutrients have significant impacts on water quality, and the algicidal microbial community was driven by the algal group. Redundancy analysis results showed that algicidal flora was positively related to Chlorophyll(a) and water quality but not to Cyanobacteria. Interestingly, bacterial organic carbon biosynthesis, ammonification process, and dissimilatory sulfate reduction decreased, while organic carbon decomposition and assimilatory sulfate reduction functions increased in ABM compared to UABM. These results highlight the algal bloom disturbed the nutrients cycle and planktonic microbial community and suggest that algicidal flora in the bloom area may primarily target eukaryotic algae rather than Cyanobacteria.
藻华是当前主要问题之一，然而藻华对浮游微生物群落的影响仍不明确。本研究调查了太湖西部、东部、北部和中部地区12个采样点在藻华期的水质和表层沉积物中的养分以及浮游微生物群落。我们发现，四个区域上覆水中的总氮、铵态氮、叶绿素(a)和化学需氧量平均浓度存在显著差异(p < 0.05)。东部湖区细菌和微型真核生物群落的α多样性指数最高，物种周转对浮游微生物群落的组成差异很重要。根据养分、叶绿素(a)和主坐标分析结果，划分出五个藻华(ABM)和五个非藻华站点(UABM)。零模型显示，除确定性过程外，随机过程发挥了更大作用，与UABM相比，ABM内的微生物群落中扩散限制降低，异质性选择增加。网络分析表明，藻华通过破坏浮游植物、原生动物、后生动物和细菌之间的相互作用，使浮游微生物食物网不稳定。偏最小二乘路径建模分析表明，沉积物养分对水质有显著影响，杀藻微生物群落受藻类群体驱动。冗余分析结果表明，杀藻菌群与叶绿素(a)和水质呈正相关，但与蓝藻无关。有趣的是，与UABM相比，ABM中的细菌有机碳生物合成、氨化过程和异化硫酸盐还原减少，而有机碳分解和同化硫酸盐还原功能增加。这些结果突出了藻华扰乱了养分循环和浮游微生物群落，并表明藻华区域的杀藻菌群可能主要针对真核藻类而非蓝藻。
