阳澄湖浮游植物群落结构特征及其与水环境因子的关系

Community characteristics of phytoplankton in Yangcheng Lake and relationships with water environmental factors

2014年7-11月对阳澄西湖浮游植物群落结构及其时空分布进行了调查,运用Pearson相关性分析、冗余分析(RDA)与水环境因子的相关性进行了分析。调查期间共发现浮游植物8门68属142种,其中绿藻门63种,占44.37%,硅藻门27种,蓝藻门22种。优势种中绿藻门种数最多,其中61.11%的优势种为富营养型水体指示藻类。细胞密度年均(3.99±4.00)×106cell/L,生物量年均(1.41±1.05)mg/L,夏季均高于秋季;夏秋季藻类密度以蓝藻门最高,生物量则以硅藻门最高。多样性指数结果表明,阳澄西湖水质总体显示为中污染,其中秋季水质状况优于夏季。Pearson相关性分析表明,阳澄西湖夏季浮游植物现存量主要与pH、水温、NO-2-N呈正相关,秋季则主要与NO-2-N、CODMn、DTN和DTP有关。RDA分析显示,夏季浮游植物水平分布的主要影响因子是T、TN和DTP,而pH、T、DO和DTN为秋季藻类分布的主要影响因子。

An investigation was conducted in Yangcheng Lake from July to November,2014,Pearson correlation analysis and redundancy analysis（ RDA） were applied to analyze the relationship between the phytoplankton community structure and water parameters. 142 species, 68 genera and 8 phyla were identified,including Chlorophyta（ 63 species,accounting for 44. 37%）,Bacillariophyta（ 27 species）,Cyanophyta（ 22 species）. The number of Chlorophyta was the highest in dominant species,while Cyanophyta was with the highest density. 61. 11% of the dominant species were indicating algae of rich nutritional water.Abundance and biomass of phytoplankton during summer [averaging（ 3. 99 ± 4. 00） × 106 cell / L and（ 1. 41 ± 1. 05） mg /L,respectively] were considerably higher than those during autumn. Besides,algal density was mainly composed of Cyanophyta,while biomass was mainly composed of diatoms. The results showed that the water quality in Yangcheng Lake was moderately-polluted and the water during autumn was better than summer. The results of Pearson correlation analysis showed that the primary factors affecting the structure of phytoplankton community were identified to be p H,Tem and NO-2-N content during summer.Contents of NO-2-N,CODMn,DTN and DTP were the main factors affecting the structure of phytoplankton community during autumn. RDA results indicated that the key environmental factors influencing the phytoplankton assemblages were Tem,TN and DTP,whereas p H,Tem,DO and DTN were the key factors during autumn.