Study On The Community Structure Of River Macroinvertebrates And Its Influence Mechanism Of Diversion Power Station

In order to solve the ecological environment effect caused by dam on the river,river diversion type power station built in this paper,and not to build power plants for continuous monitoring of the water temperature of river and the river with field investigation,benthic animals for research with diversion water temperature of river and along the change law of benthic animals,adopt comparative analysis research method,selection of Nanyang river diversion type power station built and the Qingjiang river upstream section of river diversion type power station（not built）as the research object,choose nine on Nanyang river section,select five section on Qingjiang river,a total of 14 monitoring cross section,Temperature of two rivers and zoobenthos and a year monitoring water physical and chemical properties,by utilizing the method of comparison and analysis of river water,physical and chemical properties,water temperature,macroinvertebrates were analyzed,and through linear fitting to build two months river section average monthly temperature and longitudinal distance,and the relationship between the altitude explore the change rule of water temperature on the longitudinal,the research of the main results were as follows:Firstly,In September,compared with March,the chlorophyll content of Nanyang River water was lower than 2g/L,the temperature change range of each section reached 5～10℃,the dissolved oxygen presented a downward trend with the rise of water temperature,the turbidity of the water was lower than 20NTU,and the conductivity of the water increased.The contents of TN,NH₄⁺-N and NO₃^--N in water decreased,while the TP content increased.Compared with April and August,the chlorophyll content in Qingjiang water body is at a low level,turbidity does not change much,water temperature varies greatly with seasonal changes,dissolved oxygen content changes with seasonal changes of water temperature,and ORP and conductivity of water body do not change much.The content of TN,NO₃^--N and NH₄⁺-N in Qingjiang water body is at a low level.The TP content in August（except QJ05）is lower than that in April.The nitrogen and phosphorus content in water body changes seasonally.Secondly,Compared with Nanyang River,the turbidity of Qingjiang river is less than20NTU.Conductivity and ORP vary with seasonal variation,and dissolved oxygen varies with water temperature.In March,the average TN,NO₃^--N and TP content of Nanyang River was lower than that of Qingjiang River,and the average NH₄⁺-N content was higher than that of Qingjiang River.In September,the average contents of TN,NO₃^--N,NH₄⁺-N and TP in Nanyang River were all lower than those in Qingjiang River.Thirdly,the Qingjiang with Nanyang river water temperature along the change present a linear correlation of daily variation on the water temperature along the do not have linear correlation,monthly average water temperature variation along the river are similar,both present a linear correlation between the monthly average temperature of the linear fitting results show that the average monthly temperature along the change of Nanyang river is averaging 0.59 above,the fit of the linear and nonlinear fitting altitude of 0.57 above,Qingjiang water temperature along the change of linear fitting are reaching more than 0.79,and the elevation of the nonlinear fitting are reaching more than 0.86.Fourth,the macroinvertebrates of Qingjiang river were mainly composed of Pipi and snails.The density of macroinvertebrates increased along the course,and the species of macroinvertebrates in all sections were basically the same.The Margalef index varied from0.54 to 1.49,the Simpson index from 0.3 to 0.76,the Shannon-Wiener index from 0.53 to1.55,and the Pielou evenness index from 0.33 to 0.87.Except for the source,the water quality of the other sections was severely to moderately polluted.Fifth,compared with the biodiversity of the two rivers,the species quantity and biodiversity index of Nanyang River are higher than that of Qingjiang River,and the water quality is better than that of Qingjiang River.The water body of Nanyang River is generally oversaturated with an average content of 8.62mg/L in each section,which is conducive to the survival of macroinvertebrates.However,the average content of dissolved oxygen in Qingjiang River reaches 7.46mg/L.Therefore,the content of dissolved oxygen in the water body is not the main factor limiting macroinvertebrates.The sediment particle size of Nanyang River is higher than that of Qingjiang River,which is more suitable for macroinvertebrates to live.Moreover,the riverbed is mostly filled with pebble particles,providing suitable living space for macroinvertebrates.Sixth,with the rise of water temperature,the biological density of macroinvertebrates in Qingjiang River increased rapidly,and the number of species increased,but the number of macroinvertebrates decreased,the distribution of individual species was uneven,and the dominance of macroinvertebrates decreased.