| 基于时间序列分析的青草沙水库浮游植物群落结构的变化 |
| 摘要点击 1209 全文点击 300 投稿时间：2023-10-08 修订日期：2024-01-12 |
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| 中文关键词 青草沙水库 浮游植物 群落结构 理化指标 易消化藻类 |
| 英文关键词 Qingcaosha Reservoir phytoplankton community structure physicochemical indexes digestible algae |
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| 中文摘要 |
| 青草沙水库是上海重要水库之一,为饮用型水源地.于2014~2021年每月在该水库采样,分析浮游植物群落结构和水环境因子,以期为城市水库调度管理、水资源保护以及开发利用提供合理的参考依据.结果表明,8 a共鉴定出浮游植物8门561种,以硅藻门、绿藻门和蓝藻门为主,分别占总物种数的34.94%、34.58%和17.65%.年度优势种共有4门26种,蓝藻门最多,占比为50%.浮游植物丰度变化范围为8.391×105~2.115×107 cells·L-1,平均为6.345×106 cells·L-1.浮游植物生物量变化范围为0.113~11.903 mg·L-1,平均为1.538 mg·L-1.时间分布上,丰度最大值出现在夏季、生物量最大值出现在春季.空间分布上,生物量和丰度最大值都出现在库中.浮游植物群落结构与水环境因子的冗余分析（RDA）表明,水温（WT）、溶解氧（DO）和营养盐（TN、TP）是影响浮游植物群落结构的重要环境因子.鲢、鳙和鲤鱼与易消化藻类的RDA分析表明：在春季、秋季和冬季,易消化藻类生物量与鲢鳙鱼和鲤鱼生物量呈正相关关系.这些结果说明藻类的易消化性改变了滤食性鱼类的资源利用效率,导致浮游植物的群落结构发生变化. |
| 英文摘要 |
| Qingcaosha Reservoir is one among the important reservoirs and drinking water sources in Shanghai. Samples were collected from the reservoir every month from 2014 to 2021 to analyze phytoplankton community structure and water environmental factors to provide a reasonable reference for urban reservoir operation management, water resource protection, and development and utilization. The results showed that 561 species of phytoplankton were identified from eight phyla in 8a, mainly diatomata, chlorophyta, and cyanophyta, accounting for 34.94%, 34.58%, and 17.65% of the total species, respectively. A total of 26 dominant species were present in four phyla, and cyanobacteria accounted for 50%. Diatoms and green algae were the dominant species, cyanobacteria was the absolute dominant species, and other phyla accounted for a low proportion in the community structure. The Qingcaosha reservoir had the tendency of transforming into a cyanobacteria-type reservoir. The major dominant genera of chlorophyta were Scenedesmus, Ankistrodesmusc, and Chlorellaceae. The dominant genera of the phylum cyanobacteria were Merismopediaceae, Microcystaceae, Aphanocapsa,and Pseudanabaenaceae. The major dominant genera of the diatoms were Cyclotella, Melosira,and Aulacoseira. The dominant genus of xanthophyta was Tribonemataceae. Phytoplankton abundance ranged from 8.391×105 to 2.115×107 cells·L-1, with an average of 6.345×106 cells·L-1. The biomass of phytoplankton varied from 0.113 to 11.903 mg·L-1, with an average of 1.538 mg·L-1. The maximum abundance occurred in summer, and the maximum biomass occurred in spring. In spatial distribution, the maximum biomass and abundance appeared in the reservoir. Redundancy analysis （RDA） of phytoplankton community structure and water environmental factors showed that water temperature （WT）, dissolved oxygen （DO）, and nutrient salts （TN, TP） were important environmental factors affecting phytoplankton community structure, and significant changes occurred in 2014-2017 and 2018-2021. From 2018 to 2021, cyanobacteria disappeared and cyanobacteria dominated the reservoir and even changed to cyanobacteria-type reservoirs. From 2016 to 2021, half of the dominant species were cyanobacteria, and the cyanobacteria abundance accounted for the highest proportion during this period. The reasons for the extinction of xanthophyta were speculated to be the increase in phosphorus concentration and water temperature, and the reasons for the dominant position of cyanophyta, to be the rise of water level, water temperature, and alkaline water. Reservoirs use filter-feeding fish to control algal overgrowth； however, filter-feeding fish do not filter all algae and not all of their filter-feeding algae is easily digestible. In this study, it was observed that the size of digestible algae biomass in the four seasons was in the order of spring > summer > autumn > winter. RDA analysis of silver carp, bighead carp, and digestible algae showed that the biomass of digestible algae was positively correlated with that of silver carp and bighead carp in spring, autumn, and winter. These results suggest that the digestibility of algae changed the resource use efficiency of filter-feeding fish and led to changes in phytoplankton community structure. The phytoplankton community structure was directly affected by the descending effect of fish and indirectly affected by the digestibility of algae. |
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