小东江茂名段浮游生物及污染状况分析

Analysis of Plankton and Pollution State in Xiaodongjiang River in Maoming Area

2007年7月对茂名市小东江的浮游生物及污染状况进行调查和分析,结果共检出浮游植物122种,其中蓝藻门15属34种,占（总种类数,下同）27.9%,硅藻门16属26种,占21.3%,绿藻门29属52种,占42.6%,裸藻门3属6种,占4.9%,金藻门1属1种,占0.8%,黄藻门3属3种,占2.5%;浮游动物78种,其中原生动物门26属36种,占46.2%,轮虫动物门9属16种,占20.5%,节肢动物门枝角类8属14种,占17.9%,桡足类10属11种,占14.1%,水生昆虫1属1种,占1.3%。各调查断面浮游植物的种类数平均为37种,细胞密度在11.3×104~19.5×104/L,Ⅴ断面最高,Ⅰ断面最低,平均为14.4×104/L;浮游动物种类数平均为27种,密度平均为2 895/L。相邻断面间Jaccard种类相似性指数范围为0.13~0.23,各断面环境异质性相差较大,该季节河水流动性小。叶绿素a含量为19.9~45.3μg/L,它与细胞密度呈显著的正相关,与无机氮、无机磷和COD均不存在明显的相关性。各断面的浮游植物多样性指数为3.1~4.5,均匀度为0.62~0.85;浮游动物的多样性指数为2.7~3.9,均匀度我0.59~0.80。对βm-αm指示种种类组成和群落结构分析,Ⅱ、Ⅲ、Ⅳ、Ⅴ断面水质属生态中污类型,而Ⅰ断面属生态寡污类型。以国家地表水质量标准评判,各断面COD含量为Ⅰ类水;无机氮含量除Ⅰ断面外,其他断面均为Ⅲ类水;无机磷含量均优于Ⅱ类水;石油类除Ⅰ、Ⅱ断面为Ⅳ类水外,其他断面均为Ⅴ类水。单因子污染指数分析表明,小东江流域水质为中污染至重污染之间。

Field investigations and laboratory analysis were conducted on the planktons and the pollution in Xiaodongjiang river,Maoming city,Guangdong Province of China in July,2007.The results showed that a total of 122 species of the phytoplankton belonged to 67 genus;6 phyla were ascertained and 78 species of the zooplankton belonged to 54 genus;3 phyla were also found.Among phytoplankton,15 genus including 34 species belonged to Cyanophyta,accounting for 27.9% of all species,16 genus including 26 species were Bacillariophyta,accounting for 21.3%,29 genus including 52 species were Chlorophyta,accounting for 42.6%,3 genus including 6 species were Euglenophyta,accounting for 4.9%,1 genus including 1 species were Chrysophyta,accounting for 0.8%,and 3 genus including 3 species were Xanthophyta,accounting for 2.5%.Among zooplankton,26 genus including 36 species belonged to Protozoa,accounting for 46.2% of all species,9 genus including 16 species were Rotatoria,accounting for 20.5%,8 genus including 14 species were Cladocera,accounting for 17.9%,10 genus including 11 species were Copepoda,accounting for 14.1%,and 1 genus including 1 species were Diptera,accounting for 1.3%.The average species of phytoplankton was 37 every sections,the cell abundance ranged from 11.3×104 ind/L to 19.5×104 ind/L and the average individuals was 14.4×104 ind/L,with a maximum in the fifth section and a minimum in the first section. The average species of zooplankton was 27 and the average abundance was 2895 ind/L. Jaccard index was between 0.13 and 0.23 in each assembly of both sections, which meant the environmental diversity were six to one and the river liquidity was weak in this season. The concentration of chlorophyll a which ranged from 19.9 to 45.3 μg/L showed a significantly positive correlativity with the density of phytoplankton while there were not obvious correlation between the concentration of chlorophyll a, inorganic nitrogen, inorganic phosphorus and COD. The phytoplankton diversity index and evenness were respectively 3.1 - 4.5 and 0.62 - 0.85, and the zooplankton ones were respectively 2.7 - 3.9 and 0.59 - 0.80 in every section. From the analysis of the species and community composition of the βm-αm indicated species, it was found that the water quality belonged to the ecological middling pollution type in the Ⅱ,Ⅲ,Ⅳ and Ⅴ section and the ecological few types of pollution for the first section. According to the Environmental Quality Standards For Surface Water, the concentration of COD was theⅠtype in every section, the concentration of inorganic nitrogen was the Ⅲ type except for theⅠsection, and the concentration of inorganic phosphorus was excelled theⅡtype in all sections. The concentration of oil in each section was over the value of the fifth type except for the first and second sections. The water quality belonged to the grade between the middle and heavy pollution from the pollution index of single factor.