生态修复对浮游植物种群结构的影响

Influence of Ecosystem Repair on Phytoplankton Species Structure

惠州南湖(惠州西湖子湖之一)是典型的亚热带浅水城市湖泊。2007年5月,惠州西湖开展了以水生植被构建和鱼类调控为主的生态系统修复与构建(中试)工程,以控制湖泊富营养化,改善湖泊水质。生态修复后南湖中试区的营养盐含量和富营养化程度有很大的下降,其中TP降低了87.04%,TN下降了64.25%,N∶P比由5月份的6.99∶1升高到18.32∶1。生态修复前浮游植物浮游植物优势种有10种(属)5个门,其中绿藻为优势种群,约占浮游植物总生物量的72.79%。多样性指数为2.03,均匀度为1.095,为富营养化的稳态阶段;生态修复后浮游植物浮游植物优势种有20种(属)6个门,其中隐藻为优势种群,约占总生物量的52.84%,多样性指数为3.58,均匀度为1.113,为清水态型生态系统。生态修复后浮游植物的丰度、生物量以及各种属之间的比例关系发生了较大的变化。通过生态修复工程已经打破了浮游植物的稳态阶段,建立多藻共存的水生态系统,是藻类共存和多样性研究在工程当中一个成功的应用。

The south lake （one of the son lakes of Huizhou West Lake） of Huizhou is a typical subtropics shallow city lake. In May, 2007, ecosystem repair and construction project （pilot test） which focused on phytoplankton construction and fishes regulation in Huizhou West Lake were carried out to control lake eutrophication and improve water quality. After repairing, the nutrient content and eutrophication level has descended greatly in the south lake, in which, the total phosphate reduced by 87.04%, the total nitrogen reduced by 64.25%, and the ratio of nitrogen phosphate was 18.32：1 increasing from 6.99：1 in May. Before ecosystem repair, the dominant species included 10 kinds, in which Chlorophyta was dominant and occupied 72.79% of the total biomass. Diversity index was 2.03 and evenness was 1.095 in the south lake which was in the stable stage of eutrophication. After ecosystem repair, the dominant species included 20 kinds, in which Cryptophyta was dominant and occupied 52.84% of the total biomass. Diversity index was 3.58 and evenness was 1.113 in the south lake which was defined as clean water ecosystem. The abundance, biomass and species proportion of phytoplankton occurred a large change. Ecosystem repair engineering broken the stable stage of phytoplankton to build a water ecosystem of multi-algae coexistence which was a successful application in algae coexistence and diversity research.