The Community Characteristics Of Zooplankton In The Water Body Of Suzhou Industrial Park And Its Relationship With Environmental Factors

The monthly sampling data from October 2012 to September 2013 were used to analyze the composition and community structure of the zooplankton both in the lakes and rivers of Suzhou Industrial Park.The variations of density and biomass of the zooplankton and the relationship with the environment factors were investigated.(1)A total of 82 species of zooplankton were found in lakes,including 46 species of rotifers which belong to 10 families and 21 genera,17 species of cladocerans which belong to 5 families and 9 genera,and 19 copepods which belong to 9 families and 13 genera.A total of 83 species of zooplankton were found in rivers,including 49 species of rotifers which belong to 10 families and 24 genera,16 species of cladocerans which belong to 4 families and 8 genera,and 18 copepods which belong to 9 families and 13 genera.The dominant species were Keratella cochlearis,Polyarthra trigla,Bosmina longirostris,Sinocalanus dorrii,Cyclops vicinus vicinus and Halicyclops sinensis both in the lakes and the rivers during the study period.(2)The density and biomass of the rotifers in spring and summer were higher than that of in winter and autumn,and two peaks were found in spring and summer respectively both in the lakes and the rivers.The average density and biomass of rotifers in the rivers were higher than that of in the lakes,and there is no significant difference between the rivers and the lakes(F1,274 = 0.155,P=0.694;F1,274 = 2.102,P=0.148).The peaks of the density and biomass of the cladocerans were all in May for the lakes and the rivers.The average density and biomass of cladocerans in the rivers were higher than that of in the lakes,and the difference between density is more significantly(F1,274 = 11.052,P<0.001),and that for biomass is significantly(F1,274 =7.830,P = 0.006).The peaks of the density and biomass of the copepods were in October for the lakes and the rivers,the average density and biomass of the copepods in the rivers were higher than those in lakes,and the differences between them were most significantly both for the density and biomass(F1,274 = 45.347,P<0.001;F1,274= 41.210,P<0.001).(3)The Shannon-wiener diversity index of rotifers in the lakes and rivers varied from 0.92 to 2.61 and 1.84 to 2.74 respectively,and the difference between them is most significantly(F1,274= 15.502,P<0.001).The Pielou index varied from 0.55 to 0.82 for the lakes and 0.68 to 0.84 for the rivers,and the difference between them is significantly(F1,274 = 4.454,P = 0.036).The Shannon-wiener diversity index of crustacean zooplankton in Suzhou Industrial Park varied from 1.77 to 3.15 for the lakes and 1.36 to 2.94 for the rivers,and there was the most significant difference between them(F1,274=29.678,P<0.001).The Pielou index varied from 0.54 to 0.87 for the lakes and 0.48 to 0.83 for the rivers,and there was no significant difference(F=1,274=3.344,P = 0.069).The Shannon-wiener diversity index and Pielou index were used to assess the water quality,and the annual results showed that the water quality of Suzhou Industrial Park could be classified as mesosaprobic status(a-mesosaprobic or p-mesosaprobic).(4)According to the redundancy analysis of the dominant species and environmental factors in Suzhou industrial park,the main factors affecting the dominant of rotifers distribution were water temperature,dissolved oxygen,pH and secchi depth.Both in the rivers and lakes,the density of rotifer species,Trichocerca pusilla and Anuraeopsis fissa,were correlated with water temperature positively,but with dissolved oxygen and secchi depth negatively;the density of Brachionus angularis,Brachionus calyciflorus,Keratella cochlearis,Polyarthra trigla,Synchacta oblonga and Synchacta tremula were correlated with pH,dissolved oxygen,secchi depth positively,but with water temperature and salinity negatively.All the dominance species of crustacean zooplankton were correlated with water temperature positively and with dissolved oxygen and secchi depth negatively in rivers.The density of Daphnia hyalina,Daphnia lumholtzi and Schmackeria inopinus were positively correlated with secchi depth,pH and total nitrogen,and negatively correlated with water temperature.