珠江三角洲河网桡足类群落结构及其与水环境因子的关系

为了解珠江三角洲典型河网水域浮游桡足类的生态特征,于2012年3月、5月、8月和12月对该水域进行4个季度的采样调查,通过数据分析,对桡足类的种类组成、现存量及生物多样性等指标进行了分析。共鉴定桡足类9科24属31种,以及桡足幼体和无节幼体。结果显示,该水域桡足类优势种的季节演替及空间变化明显,广布中剑水蚤(Mesocyclops leuckarti)、跨立小剑水蚤(Microcyclops varicans)和透明温剑水蚤(Thermocyclops hyalinus)等种类为常见种。桡足类及无节幼体的现存量分布具有明显的季节变化,丰水期现存量大于枯水期;桡足类现存量的平面分布较为均匀,无节幼体的现存量基本呈现自西南向东北方向降低的趋势。总体看来,丰水期桡足类的平均生物多样性指数及均匀度指数高于枯水期,空间分布格局基本呈现自西南向东北方向降低的趋势。PCA分析结果表明,珠江三角洲河网水域桡足类群落结构与水温、总磷、总氮、氨氮、高锰酸盐指数以及叶绿素a含量呈显著正相关,与透明度和p H呈显著负相关。

Community structure of copepods and the relationship with aquatic environmental factors in the Pearl River Delta

The Pearl River Delta (PRD) in Guangdong province is one of the most economically prosperous areas in China. Economic development in this region has resulted in an estimated 10% increase in the volume of domestic and industrial wastes in the past few years. The complex river web of the delta, characterized by multiple river channels, forms the entrance for the Pearl River into the South China Sea. A number of studies have focused on measuring the physical and chemical factors in this region, but there has been little attention paid to aquatic organisms. Our objective was to document the ecological characteristics of copepods in the river network of the Pearl River Delta. The species composition, biomass, and biodiversity of copepods were measured in samples collected from the water in March, May, August, and December of 2012. A total of 31 copepod species representing 24 genera and 9 families were identified, including copepodids and nauplii. The dominant copepod species exhibited seasonal and spatial changes in abundance, with being the most common species. The biomass of copepods and nauplii exhibited seasonal changes in abundance, and both were more abundant during the wet season than in the dry season. The copepod biomass was characterized by even horizontal distribution, whereas the nauplii biomass generally decreased along a gradient from southwest to northeast. In general, the average biodiversity and evenness indices were higher in the wet season than in dry season, and decreased from the southwest to northeast. The results of principal component analysis revealed that the community structure of copepods in the Pearl River Delta river network was significantly positively correlated with temperature, total phosphorus, total nitrogen, ammonia nitrogen, and permanganate contents, positively correlated with chlorophyll acontent, and significantly negatively correlated with water transparency and pH.