田湾核电站海域浮游动物生态特征

2009年8月在田湾核电站附近海域进行了海洋浮游动物及环境因子的调查,在14个调查站位共鉴定浮游动物10大类43种.其中原生动物5种,水螅水母类17种,栉水母类2种,枝角类2种,桡足类11种,糠虾2种,樱虾类1种,磷虾1种,毛颚类1种,被囊类1种.浮游动物的丰度范围为99-2546个/m3,平均值为834个/m3.主要优势种为薮枝螅水母、太平洋纺锤水蚤、背针胸刺水蚤、鸟喙尖头潘、异体住囊虫、汤氏长足水蚤、强壮箭虫.优势度分别为0.804、0.586、0.569、0.485、0.197、0.140、0.116.各类指数变幅较大(种类数为9-17,丰富度指数为0.913-1.770,多样性指数为1.170-3.212,均匀度指数为0.369-0.803).多样性指数均值为2.188,均匀度指数均值为0.587,丰富度指数均值为1.336.相关性分析表明,水温与浮游动物丰度及种类数之间具有显著的相关性,相关系数(r)分别为-0.615和-0.574,P＜0.05；种类数与多样性指数、丰富度指数及均匀度指数有显著的正相关,相关系数(r)分别为0.730、0.759(P＜0.01)和0.552( P＜0.05),水温升高使浮游动物种类数减少；水温与氨氮含量之间有极显著的正相关性,氨氮含量与浮游动物种类数之间有极显著的负相关性,水温升高使氨氮上升引起浮游动物种类数下降,温排水导致调查海域水温升高引起了浮游动物群落多样性指数、丰富度指数及均匀度指数的下降.调查海域水质状况的生物多样性指数评价显示,目前该海域水质总体处于轻度污染.

Zooplankton ecology near the Tianwan Nuclear Power Station

Zooplankton are a secondary producer in the world's oceans. Changes in the species assemblage or abundance of zooplankton has a direct impact on both primary productivity and the biomass of fish and other marine animal resources. Because, zooplankton are a key member of marine food webs, they have been the focus of a number of studies in the Yellow Sea. However, the majority of these studies have evaluated zooplankton population dynamics at a large scale (e.g., the entire Yellow Sea). To date, there has been little effort to understand the effect of local anthropogenic activity, such as the discharge of nuclear cooling water, on zooplankton ecology. We evaluated the species composition, quantitative distribution, dominant species, and community structural characteristics of zooplankton at 14 inshore sites near the Tianwan nuclear power station (34.62°-34.76°N,119.46°-119.66°E) in August 2009. We identified 43 species belonging to 10 groups, including 5 species of Protozoa, 17 species of Hydromedusae, 2 Ctenophora, 2 Cladocera, 11 species of Copepoda, 2 Mysidacea, 1 Sergestidae, 1 Euphausiacea, 1 Chaetognath, and 1 Urochordata. The abundance of zooplankton ranged from 99 to 2546 ind/m³ (mean 834 ind/m³). The most abundant group were the Hydromedusae followed by the Copepoda. Twelve species had a dominance index ranking of >0.02 within the study area. Among these, Obelia spp., Acartia pacifica, Centropages dorsispinatus, Penilia avirostris, Oikopleura dioica, Calanopia thompsoni, and Sagitta crassa were the primary dominant species (dominance index: 0.804, 0.586, 0.569, 0.485, 0.197, 0.140, and 0.116, respectively). The amplitude of the index varied significantly (species: 9 to 17, richness: 0.913-1.770, diversity index: 1.170-3.212, evenness index: 0.369-0.803) suggesting the community structure was instable. The mean diversity index of zooplankton was 2.188, the mean richness index was 1.336, and the mean evenness index was 0.587. Water temperature and the abundance and the number of species were significantly correlated (P<0.05) (correlation coefficients: -0.615 and -0.574, respectively; P<0.05). We observed a significant relationship between the number of species and the diversity, richness, and evenness indices (correlation coefficients: 0.730, 0.759 (P<0.01), and 0.552 (P<0.05), respectively. There was a reduction in the number of zooplankton species as the temperature increased. We found a significant negative correlation between ammonia nitrogen content and water temperature and between ammonia nitrogen content and the number of species. Increases in temperature lead to increased ammonia, resulting in a decline in the number of zooplankton species. Thus, we hypothesize that increases in water temperature due to discharge of nuclear power cooling water have caused a decrease in the zooplankton community diversity, richness, and evenness indices in the nearshore region around the Tianwan nuclear power station. The zooplankton diversity index has since been adopted to assess water quality around the Tianwan nuclear power plant. Monitoring results suggest a low level of water pollution.