长江口南北支浮游甲壳动物的比较及南水北调工程影响预测

Comparison of planktonic crustaceans in north and south branches at Yangtze River estuary and impact prediction of South-to-North Water Transfer Project

南水北调东线、中线工程实施后将给长江口水生生物的生态环境带来影响。2005年秋季和2006年春季,对长江口南、北支浮游甲壳动物进行了2航次的调查。调查区域从长江口徐六径至河口50号灯标,全长181.8km,自西向东江面宽由约5.7km扩展为约90km,平面形态呈扇形分布,设立3个断面14个调查采集点。采集到浮游甲壳动物共23科37属54种,其中枝角类6科8属15种,桡足类17科29属39种;秋季种类数多于春季,北支桡足类种类数多于南支;平均总密度为9.10ind.L-1,平均总生物量为0.1179mg.L-1,以桡足类为主;北支III断面的现存量远远高于南、北支其他断面;长额象鼻溞、简弧象鼻溞为优势枝角类;中华华哲水蚤、汤匙华哲水蚤、球状许水蚤、广布中剑水蚤为优势桡足类。文中还对长江口南、北支浮游甲壳动物的总体水平及时空分布、南水北调对浮游甲壳动物的影响进行了分析。

The implementation of South-to-North Water Transfer Project will bring about some impacts on the ecological environment of aquatic organisms at Yangtze River estuary. Planktonic crustaceans are the one of important components of aquatic organisms. In this study, the planktonic crustaceans in the north and south branches at Yangtze River Estuary were surveyed in autumn 2005 and spring 2006, with the region from Xuliujing to lighthouse 50 on the estuary, a total length of 181.8 kin, and a broad expansion from west to east about 5.7 km to about 90 km with a fan-shape. Three cross-sections and 14 survey points were established. A total of 54 planktonic crustacean species, which belonged to 37 genera under 23 families, were recorded. There were 15 species of eladoeerans belonging to 8 genera under 6 families, and 39 species of copepods belonging to 29 genera under 17 families. More planktonic crustacean species were observed in autumn than in spring, and more copepod species were found in north branch than in south branch. Planktonic crustaceans had an average density of 9. 10 ind · L^-1, and their total biomass, mainly composed of copepods, was 0. 1179 mg· L^-1. The standing crop at cross-section Ⅲ in the north branch was far higher than that at other sections. Bosmina longirostris and Bosmina coregoni were the dominant species of cladocerans, and Sinocalanus sinensis, S. dorrii, Sehmackeria forbesi and Mesocyelops pehpeiensis were the dominant species of copepods. The overall level and spatiotemporal distribution of planktonic crustaceans in the north and south branches of Yangtze River estuary and the impacts of the Water Transfer Project on the planktonic crustaceans were also analyzed.