淀山湖河蚬与翘嘴红鲌国家级水产种质资源保护区水质评价及初级生产力时空变化特征

为了解淀山湖河蚬与翘嘴红鲌国家级水产种质资源保护区的水质及初级生产力现状,2015年在保护区选取了10个采样点进行了野外采样和实验室研究,运用综合营养状态评价和相关性分析,分析了当前淀山湖保护区水质因子和初级生产力的时空变化特征,以及叶绿素a(Chl.a)与环境因子之间的关系。研究结果表明:保护区营养元素含量、高锰酸盐指数(COD_(Mn))和Chl.a含量季节间差异显著,呈现为春夏季节高于秋冬季节,而实验区与核心区无明显差异。水体N/P值范围为5.30~64.66,氮磷比适宜藻类生长。综合营养状态指数范围为46.67~60.70,水体为轻度富营养状态。保护区Chl.a变化范围为6.06~29.37 mg/m~3,初级生产力范围为65.18~1 423.11mg/(m~3·d),叶绿素a含量和初级生产力时空变化较为一致,均为季节间差异较大,而核心区与实验区无显著差异。Pearson相关性分析结果表明保护区Chl.a含量与TN、TP均呈极显著相关,相关系数(R2)分别为0.501和0.432。保护区氮磷含量均处于较高水平,这为保护区水华的发生奠定了基础。

The spatiotemporal variations analysis of water quality and primary productivity in Dianshan Lake National Aquatic Germplasm Resources Conservation Area of Asian Clam and Erythroculter Ilishaeformis

In order to investigate the water quality and primary productivity of national aquatic germplasm resources conservation area of asian clam and erythroculter ilishaeformis in Dianshan Lake, ten sampling points were chosed in the conservation area in 2015. The spatiotemporal variations of nutrients, chlorophyll-a (Chl.a) and primary productivity, and the relationship between Chl.a and environmental factors were analyzed by comprehensive nutrition status assessment and correlation analysis. The results showed that the concentrations of nutrients, COD_Mn and Chl.a had a significant difference. The results in spring and summer were higher than autumn and winter. But there was no significant difference in the test area compared with the core area. The N/P (nitrogen and phosphorus) ratios were between 5.30-64.66 and they are suitable for the algal growth. The comprehensive nutrition state index in conservation area was between 46.67 to 60.70. It showed the water columns in conservation area were in mild eutrophication state. The variations of Chl.a concentration and primary productivity were between 6.06 to 29.37 mg/m³ and 65.18 to 1 423.11 mg/(m³·d), respectively. The spatiotemporal variations of them were similar. There was a significant difference between the seasons, but there was no significant difference in the test area compared with the core area. The Pearson Correlation Analysis showed there was a significant correlation between the concentrations of Chl.a and TN, TP. The correlation index (R²)of them were 0.501 and 0.432, respectively. The concentrations of nitrogen and phosphorus were higher. They could lead to the water-bloom occurrence in this conservation area.