| According to the research made in all seasons from spring/May, summer/July, autumn/September to winter/October, diverse zooplankters were accumulated javascript:void(0);in the thirteen collection areas of nine pre-set sections in River NEN. Qualitative and quantitative analysis of collected zooplankter samples, whose community structure and bio-diversity were combined with the chemical index of NEN’s downstream, led to the comprehensive analysis of NEN’s downstream quality conditions by various professional methods.There are totally4phyla,44species among which the majority were26kinds of Rotifera and11kinds of Protozoa,6kinds of Copepoda,3kinds of Cladocera.In the period,it has found15common species in the downstream of Nenjiang in which there were mainly Protozoa The dominant species has been obviously affected,which is most in the autumn.Seeing from the superiority, Filinia longiseta has most superiority.The abundance and biomass of zooplankon. were identical in the temporal and spatial distribution in the downstream of Nenjiang River.Analyzing from the seasonal variations,annual abundance and biomass from large to small sort:Autumn(Sep.)> winter(Oct.)>summer(Jul.)>spring(May.). Distributions, aver age abundance of various sampling stations in the whole year from large to small sort:10#>9#>8#>6#>5#>1#>4#>3#>7#>2#.Annual average biomass from large to small sort:9#>10#>6#>8#>3#>5#>4#>1#>2#>7#.In the investigation,Shannon-Weaver index of zooplankon in the bio-diversity index was between1.93-3.33of the zooplankon in the downstream of Nenjiang River’s;Pielou index between0.5-1.16;Margalef index between0.97-2.7.The temporal and spatial distributions of zooplankon bio-diversity indexes were remarkable. Analyzed from the seasonal distributions, The results of the three methods are the same:spring(May.)>summer(Jul.)>Autumn(Sep.)> winter(Oct.).Analyzing from the spatial distributions of the whole year,the The results of correlation analysis of the three indices can show zooplankon bio-diversity well.From the results of Multidimensional scaling analysis to the zooplankon community,it showed that zooplankon bio-diversity in the upper,middle and lower parts in spring are remarkable.And in different seasons, the samples of zooplankon are different in similarity.MDS distribution charts can demonstrate community’s distance-similarity of various samples and can also indicate that composition of various sites zooplankon community existed different obviously. |
