Research And Application Of Biological Index In The River Ecosystem Health Assessment

Any change of river ecosystem might affect of the physiological functions, species abundance, population density and community structure of the aquatic life, so biological index of the aquatic life can reflect that the river ecosystem is an important indicator of river ecosystem health. Now,we can describe the status of river ecosystem health by monitoring the changes of biomass, productivity, structural indicators, function indicators and some physiological and ecological states of biology or groups, and it has been widely used.This paper mainly investigated and studied the aquatic life, which contains phytoplankton,zooplankton and zoobenthos in Suzhou Creek Water System. Evaluat the health status of river water quality by biological index and physicochemical index,and the application of biological index in river ecosystem health assessment was discussed. The main results were briefly summarized as follows:1. The sampling sites in Suzhou Creek Water System are eutrophication water bodies from the point of view of phytoplankton biomass. The water quality in Suzhou Creek Water System belongs toα-moderately polluted zone orβ- moderately polluted zone ;Dominant species of zoobenthos is Limnodrilus hoffmeisteri, it is an anti-contaminated pollution indicators .In a word, the river health state of Suzhou Creek Water System is poor by assessment of biomass and dominant species of the aquatic life.2.Combination of physicochemical index, we assessment the river water quality health state by zooplankton Shannon-wiener index, the results are: the degree of water pollution generally stays betweenα-moderately polluted zone andβ- moderately polluted zone ;then,when we used zoobenthos Shannon-wiener index and G.B.I.index to assessment the water quality health state, the results are: the degree of water pollution generally are pollutted strictly.3.There has relevant relation between the density of phytoplankton (concentration of Chl.a) and DO in each sampling site of Suzhou Creek Water System. There also has certain correlation between H index of plankton and the physicochemical index,such as DO, transparency, TP, and so on in different situations;the G.B.I.index nd the physicochemical index, such as transparency, TP are obviously correlated.4. The dominant species which contains Oocystis lacustis, Westella botryaides, Ankistrodesmus convolutus, Aphanizomenon flosaquae ,Chlamydomonas komma are the pollution indicators inα-moderately polluted zoneorβ- moderately polluted zone in Suzhou Creek Water System;Acanthocystis erinaceus and Vorticella lutea are the pollution indicators inα-moderately polluted zone, copepod nauplii.is the pollution indicators inα-moderately polluted zoneorβ- moderately polluted zone in Suzhou Creek Water System.