Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
Water Res. 2024 May 1;254:121344. doi: 10.1016/j.watres.2024.121344. Epub 2024 Feb 20.
Changes in salinity have a profound influence on ecological services and functions of inland freshwater ecosystems, as well as on the shaping of microbial communities. Bacterioplankton, generally classified into free-living (FL) and particle-attached (PA) forms, are main components of freshwater ecosystems and play key functional roles for biogeochemical cycling and ecological stability. However, there is limited knowledge about the responses of community stability of both FL and PA bacteria to salinity fluctuations. Here, we systematically explored changes in community stability of both forms of bacteria based on high-frequency sampling in a shallow urban reservoir (Xinglinwan Reservoir) in subtropical China for 3 years. Our results indicated that (1) salinity was the strongest environmental factor determining FL and PA bacterial community compositions - rising salinity increased the compositional stability of both bacterial communities but decreased their α-diversity. (2) The community stability of PA bacteria was significantly higher than that of FL at high salinity level with low salinity variance scenarios, while the opposite was found for FL bacteria, i.e., their stability was higher than PA bacteria at low salinity level with high variance scenarios. (3) Both bacterial traits (e.g., bacterial genome size and interaction strength of rare taxa) and precipitation-induced factors (e.g., changes in salinity and particle) likely contributed collectively to differences in community stability of FL and PA bacteria under different salinity scenarios. Our study provides additional scientific basis for ecological management, protection and restoration of urban reservoirs under changing climatic and environmental conditions.
盐度变化对内陆淡水生态系统的生态服务和功能以及微生物群落的形成有深远影响。浮游细菌一般分为自由生活（FL）和颗粒附着（PA）两种形式，是淡水生态系统的主要组成部分，对生物地球化学循环和生态稳定性起着关键的功能作用。然而，对于 FL 和 PA 细菌群落稳定性对盐度波动的响应，我们的了解还很有限。在这里，我们通过在中国亚热带地区的一个浅水城市水库（杏林湾水库）进行了为期 3 年的高频采样，系统地研究了这两种形式的细菌群落稳定性的变化。我们的结果表明：（1）盐度是决定 FL 和 PA 细菌群落组成的最强环境因素——盐度升高增加了两种细菌群落的组成稳定性，但降低了它们的α多样性。（2）在低盐度波动的高盐度水平下，PA 细菌的群落稳定性明显高于 FL 细菌，而在低盐度波动的高盐度水平下则相反，FL 细菌的稳定性高于 PA 细菌。（3）FL 和 PA 细菌群落稳定性的差异可能与细菌特征（如细菌基因组大小和稀有分类群的相互作用强度）和降水引起的因素（如盐度和颗粒的变化）共同作用有关。我们的研究为气候变化和环境条件变化下城市水库的生态管理、保护和恢复提供了额外的科学依据。
