百家湖浮游植物种群结构及其富营养化状况

Community Structure of Phytoplankton and Status of Eutrophication in Baijia Lake

为揭示百家湖水环境问题,2015年对湖泊进行采样调查,选取3个生物多样性指数,采用冗余度分析(RDA)和指示物种法等方法,揭示了百家湖藻类种群构成特征、多样性及其水体富营养化状况。结果表明,百家湖检出浮游植物6门23种,优势种为隐藻、蓝隐藻、平裂藻和衣藻,优势度分别为0.32、0.09、0.03、0.03,且优势种夏、秋季略有不同,夏季以隐藻、弓形藻、二角盘星藻的丰度最高,秋季优势种为隐藻、蓝隐藻和平裂藻;生物多样性指数分析结果表明,百家湖浮游植物种群组成结构较为简单,主要由高丰度的单一耐污种组成,生物多样性不高;RDA分析结果表明TN和COD_(Mn)是影响百家湖种群结构的最主要因子,NO_3^-、Chl.a和SD等对优势种属时空分布也有一定影响;另外,水质评价结果表明百家湖水体为中度富营养化、夏季面临隐藻水华爆发的危险。

In order to reveal the problem of water environment in Baijia Lake, phytoplankton community structures were investigated in 2015 in the Baijia Lake of Nanjing. Meanwhile, three biodiversity indices were chosen, and redundancy analysis （RDA） and species indicator methods were used to analyze the status of eutrophication and environmental variables.The study identified a total of 23 phytoplankton species belonging to 6 phyla.The ecological dominance of Cryptomonas spp, Chroomonas spp, Merismopedia spp and Chlamydomonas spp respectively were 0.32, 0.09, 0.03 and 0.03. Dominant species varied in different seasons.In summer, the ecological dominance of Cryptomonas spp was the highest species, followed by Pediastrum duplex and Schroederia spp.In autumn, Cryptomonas spp, Chroomonas spp and Merismopedia spp were the dominant species. Biodiversity indices show that phytoplankton of Baijia Lake is comprised of the absolute dominant species. The results of redundancy analysis（RDA） indicates that TN and CODMn are the main factors to affect the phytoplankton community structure in the Baijia Lake, The NO-3、Chl.a and SD could also have a certain influence on the temporal and spatial distribution of the dominant species; According to the water quality and ecosystem health evaluation, the water body of Baijia Lake was currently in a moderate eutrophication state and made the water quality of this lake decline.