Institute for Advanced Marine Research, China University of Geosciences, Guangzhou 511462, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan 430074, China; College of Fisheries, Ocean University of China, Qingdao 266003, China.
Institute for Advanced Marine Research, China University of Geosciences, Guangzhou 511462, China; Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin 300457, China.
Sci Total Environ. 2023 Jun 15;877:162831. doi: 10.1016/j.scitotenv.2023.162831. Epub 2023 Mar 15.
As a typical semiclosed coastal sea area in China, the ecological environment of Bohai Bay has been significantly disturbed by human activities. As primary producers, the chromophytic phytoplankton are the basis of ecosystems, especially in coastal ecosystems, and changes in the chromophytic phytoplankton community can affect the stability of the entire ecosystem. In this study, we investigated the effects of the human activity-induced spatial and temporal environmental heterogeneity on the community composition, diversity, assembly mechanisms, and co-occurrence networks of chromophytic phytoplankton in Bohai Bay during the wet season and the dry season. The results showed that in both seasons, there was obvious environmental heterogeneity between the nearshore area and the offshore area, and the nearshore areas were more affected by human disturbance. Although higher diversity was supported by the abundance of nutrients in nearshore areas, co-occurrence network analysis revealed that the chromophytic phytoplankton were less closely connected to each other in nearshore areas than in offshore areas due to chemical oxygen demand (COD), eutrophication index (EI), and dissolved inorganic nitrogen (DIN). The nearshore network was less stable than the offshore co-occurrence network in both seasons, which was related to the concentration of dissolved oxygen and COD. Both stochastic and deterministic processes dominated the assembly of the chromophytic phytoplankton communities, with different importance rankings of stochastic and deterministic processes in the nearshore and offshore areas. Drift dominated the assembly of the communities in nearshore areas, while variable selection dominated the assembly of the communities in offshore areas. DIN, EI, and COD, rather than geographic distance, were the main environmental factors affecting the phylogenetic turnover of the chromophytic phytoplankton. Our study showed that environmental heterogeneity caused by human disturbance had a greater impact on the chromophytic phytoplankton communities in Bohai Bay than natural factors such as temperature and salinity.
作为中国典型的半封闭沿岸海域，渤海湾的生态环境受到人类活动的显著干扰。作为初级生产者，色素浮游植物是生态系统的基础，特别是在沿海生态系统中，色素浮游植物群落的变化会影响整个生态系统的稳定性。本研究调查了人类活动引起的时空环境异质性对渤海湾湿季和干季色素浮游植物群落组成、多样性、组装机制和共存网络的影响。结果表明，在两个季节，近岸区和离岸区之间都存在明显的环境异质性，近岸区受人类干扰的影响更大。尽管近岸区丰富的营养物质支持了更高的多样性，但共存网络分析表明，由于化学需氧量（COD）、富营养化指数（EI）和溶解无机氮（DIN），近岸区的色素浮游植物之间的相互联系比离岸区更为松散。近岸网络在两个季节都比离岸共生网络不稳定，这与溶解氧和 COD 的浓度有关。近岸和离岸地区的色素浮游植物群落组装过程以随机和确定性过程为主导，但随机和确定性过程的重要性排名不同。漂移主导着近岸区群落的组装，而选择变量主导着离岸区群落的组装。DIN、EI 和 COD 而不是地理距离是影响色素浮游植物系统发育周转率的主要环境因素。本研究表明，人类干扰引起的环境异质性对渤海湾色素浮游植物群落的影响大于温度和盐度等自然因素。
