象山港国华宁海电厂附近海域小型底栖动物的群落结构

于2008年夏季(6月)和冬季(12月),在象山港国华宁海电厂沿排水口右侧、从近到远相隔500m设立三个断面A、B、C,并对小型底栖动物丰度及其群落结构变化进行调查研究,结果表明:共鉴定出10个小型底栖动物类群,平均丰度达9407.9inds/10cm².从类群上看,自由生活海洋线虫占总丰度的62.3%,介形类占第二位,为19.3%.ANOSIM分析结果显示小型底栖动物季节间的丰度存在明显差异(p<0.05),夏季平均丰度(8055.3±1282.9inds/10cm²)比冬季(2141.1±614.2inds/10cm²)约高出3倍.冬季不同断面间的丰度无显著差异,但夏季断面间差异显著(p<0.05),尤其在排水口附近的A断面丰度最低,为1002.8inds/10cm².SIMPER分析结果显示海洋线虫、介形类、腹足类、涡虫、桡足类是各断面之间非相似的关键类群,这些类群的迁移指示电厂温排水已导致排水口附近海域小型底栖群落结构不稳定,不仅水平分布有差异,垂直分布也明显不同.

Community structure of meiofauna near Guohua Power Plant in Ninghai in Xiangshan Bay

Three sections(designated as A,B,C),separated by 500 m along the right outfall near Guohua Power Plant in Ninghai in XiangShan Bay,were designed and used to test changes in meiofauna abundance and community structure in summer(June) and winter(December),2008.Ten meiofauna taxa with average abundance 9407.9 inds/10 cm2 were founded.The dominant fauna was free-living marine nematoda,which accounted for 62.3 % and the following dominant one was ostracoda(accounted for 19.3 %).ANOSIM results showed that there was seasonally significant difference in meiofauna abundance(P < 0.05),and average abundance(8055.3±1282.9 inds/10 cm2) in summer was about three times higher than that in winter(2141.1±614.2 inds/10 cm2).Among three sections,no difference in abundance existed in winter,while significant difference existed in summer(P < 0.05).Furthermore,the lowest abundance in section A(1002.8 inds/10 cm2) was also founded.SIMPER analysis indicated that marine nematode,ostracoda,gastrotricha,tubellaria and copepoda were the taxa that contributed to the non-similarities among sections.Moreover,these taxa often shifted in different seasons which indicated that the meiobenthic community near the Power Plant was unstable due to the high-temperature drainage,not only in horizontal distribution,but also in vertical distribution.