School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China; Shandong Provincial Engineering Center on Environmental Science and Technology, Jinan 250061, China.
Huai'an Hydrological Bureau, Huai'an 223005, China.
Sci Total Environ. 2022 Sep 10;838(Pt 4):156637. doi: 10.1016/j.scitotenv.2022.156637. Epub 2022 Jun 11.
The intensity of cyanobacterial blooms that predominate in the world's lakes and reservoirs is variable, which may lead to differing effects on the freshwater ecosystem. Planktonic eukaryotes play key roles in the structure and function of freshwater ecosystems; however, little is known about the influence of cyanobacterial blooms on eukaryotic plankton communities and their function. Herein, the dynamics of eukaryotic plankton communities in Hongze Lake, which is the fourth largest freshwater lake in China, with a range of bloom levels occurred, from low to high, were studied to reveal the effect of cyanobacterial blooms' spatial heterogeneity on planktonic eukaryotes. Results showed that the diversity, richness, and evenness of eukaryotic plankton community were not affected by low level of bloom; however, they were decreased obviously by high level of bloom. Metazoa, Ochrophyta, Chloroplastida, Cryptomonadales, and Ciliophora were the main planktonic eukaryotes in this lake. Metazoa relative abundance declined 25.1% and relative abundance of eukaryotic phytoplankton (mainly Ochrophyta, Chloroplastida, and Cryptomonadales) and Ciliophora increased 17.4% and 2.0%, respectively, during the period with low level of bloom; conversely, the site with the high bloom level manifested the opposite changes. The linkage density of planktonic eukaryotic network was 0.188 and 0.138 with low and high level of bloom, respectively, indicating the stability of planktonic eukaryotes was lower when a high level of bloom occurred compared to that of a low bloom level. Our findings indicate that cyanobacterial blooms should be controlled at low level to avoid their obvious negative impact on microeukaryotes in lakes or reservoirs.
水华蓝藻的强度在世界上的湖泊和水库中是多变的，这可能导致对淡水生态系统的不同影响。浮游真核生物在淡水生态系统的结构和功能中起着关键作用；然而，关于水华蓝藻对真核浮游生物群落及其功能的影响知之甚少。在此，研究了中国第四大淡水湖洪泽湖中真核浮游生物群落的动态，该湖的水华水平从低到高不等，以揭示水华蓝藻的空间异质性对浮游真核生物的影响。结果表明，真核浮游生物群落的多样性、丰富度和均匀度不受低水平水华的影响；然而，高水平水华明显降低了它们的水平。后生动物、黄藻、叶绿体、Cryptomonadales 和纤毛亚门是该湖中主要的浮游真核生物。后生动物相对丰度下降了 25.1%，而真核浮游植物（主要是黄藻、叶绿体和 Cryptomonadales）和纤毛亚门的相对丰度分别增加了 17.4%和 2.0%，在低水平水华期间；相反，高水平水华的区域则表现出相反的变化。低水平和高水平水华时浮游真核生物网络的连接密度分别为 0.188 和 0.138，表明高水平水华时浮游真核生物的稳定性低于低水平水华时。我们的研究结果表明，应该控制水华蓝藻的水平，以避免其对湖泊或水库中的微真核生物产生明显的负面影响。
