Sun Xuewei, Zhang Huayong, Wang Zhongyu, Huang Tousheng, Huang Hai
Research Center for Engineering Ecology and Nonlinear Science, North China Electric Power University, Beijing 102206, China.
Microorganisms. 2022 Dec 27;11(1):75. doi: 10.3390/microorganisms11010075.
A river-estuary ecosystem usually features a distinct salinity gradient and a complex water environment, so it is enormously valuable to study the response mechanism of living organisms to multiple abiotic factors under salinity stress. Phytoplankton, as an important part of aquatic microorganisms, has always been of concern for its crucial place in the aquatic ecosystem. In this study, phytoplankton data and 18 abiotic factors collected from 15 stations in Duliujian River, a seagoing river, were investigated in different seasons. The results showed that the river studied was of a Cyanophyta-dominant type. Salinity (SAL) was the key control factor for phytoplankton species richness, while water temperature (WT) was critical not only for species richness, but also community diversity, and the abundance and biomass of dominant species. Apart from WT, the abundance and biomass of dominant species were also driven by total nitrogen (TN), nitrate (NO), pH, and water transparency (SD). Moreover, total dissolved phosphorus (TDP), pH, and chemical oxygen demand (COD) were crucial for community diversity and evenness. The bloom of dominant species positively associated with TDP led to lower diversity and evenness in autumn. In addition, when available nitrogen was limited, sp. could obtain a competitive advantage through the N fixation function. Increased available nitrogen concentration could favor the abundance of to resist the negative effect of WT. The results show that could serve as an indicator of organic contamination, and nutrient-concentration control must be effective to inhibit bloom. This could help managers to formulate conservation measures.
河口生态系统通常具有明显的盐度梯度和复杂的水环境，因此研究盐度胁迫下生物对多种非生物因素的响应机制具有极高的价值。浮游植物作为水生微生物的重要组成部分，因其在水生生态系统中的关键地位一直备受关注。本研究调查了从入海河流独流减河15个站点采集的不同季节浮游植物数据及18个非生物因素。结果表明，所研究的河流属于蓝藻门优势型。盐度（SAL）是浮游植物物种丰富度的关键控制因素，而水温（WT）不仅对物种丰富度至关重要，对群落多样性以及优势种的丰度和生物量也至关重要。除水温外，优势种的丰度和生物量还受总氮（TN）、硝酸盐（NO）、pH值和水体透明度（SD）的驱动。此外，总溶解磷（TDP）、pH值和化学需氧量（COD）对群落多样性和均匀度至关重要。秋季，与总溶解磷相关的优势种水华导致多样性和均匀度降低。此外，当有效氮有限时， 种可通过固氮功能获得竞争优势。增加有效氮浓度有利于 的丰度，以抵抗水温的负面影响。结果表明， 可作为有机污染的指标，必须有效控制营养物浓度以抑制 水华。这有助于管理者制定保护措施。
