Studies On Physico-chemical Parameter And Its Correlation With The Distribution Of Three Main Zooplanktons Collected From Rivers In Chongming Island

This study was aimed at researching six physical parameters (including water temperature, dissolved oxygen, electrical resistance, electric conductance, total dissolved solids and salinity), eighteen chemical parameters (including pH, total alkalinity, hardness, ammonia, phosphate, sulphate, colority, sulphide, sulphite, iron, fluoride, magnesium, zinc, silica, copper, potassium, manganese and nitrite) and three biological species (including Schmackeria poplesia, Tortanus vermiculus and Labidocera euchaeta) in three representative rivers ( Jie River, Puzhengang River and Baxiao River ) in Chongming Island (Shanghai) from January to October 2007. Correlation analysis, principal component analysis and cluster analysis were used to analyze the correlations among parameters mentioned above.The results of correlation analysis showed that both in low-flow and high-flow period, the relations among electrical resistance, electric conductance, total dissolved solids and salinity were stable, which can be expressed as accurate formulas. As for water temperature or dissolved oxygen, however, its relation with other parameters was nuclear. Ten relations have been found among chemical parameters no matter in low-flow or high-flow period. Some of these relations can be expressed accurately while some need further research.Except for one sample site, no different chemical component was detected in low-flow or high-flow period using cluster analysis. And five principal components with above 85% variance were extracted by principal component analysis. In low-flow period, sulphate, phosphate and potassium had high load in first component; magnesium in the second component; and iron, colority & sulphide in the third component. But in high-flow period, potassium had high load in first component; magnesium and copper in the second component; and sulphite and nitrite in the third component. The five possible mechanisms have also been supposed. The distributions of parameters in low-flow period were disciplinary, however, that of high-flow period were insignificant. In both periods, the first key factor influencing water quality was agriculture, the second was seawater, and the last was industry.There existed positive correlation between the quantity of each zooplankton and water temperature. But different correlation was observed between salinity and the quantity of each zooplankton. Also it was found that Schmackeria poplesia and Tortanus vermiculus had strong resistant capability against salinity, however, Labidocera euchaeta had weak resistant capability. As for dissolved oxygen and silica, no significant influence was spotted towards these three zooplanktons. But sulphate and fluoride can cause inhibitive effects. To sum up, the distribution of zooplanktons in targeted rivers was affected by physical parameters mostly compared with chemical parameters.