Community Structure Of Macrozoobenthos In Jiamusi Section Of Songhua River And Assessment Of The Water Quality

The Songhua river is one of the most important fresh water resources in Jiamusi area.The health of aquatic ecosystem in Songhua river affects industries and residents'daily life in Jiamusi area directly.Macrobenthos,as a very important component of aquatic ecosystem,are widely distributed,with long life history,species composition and community structure closely related to physicochemical factors of water quality.Therefore,the health of a Marine benthos community can largely reflect the health of the aquatic ecosystem.In this paper,the Songhua river basin Jiamusi section and its two typical imported branches as the research objects,to investigatethe community structure of large benthonic invertebrates and the space-time characteristics of dominant populations,and the relevance between community structure and abiotic factors of the aquatic environment were analyzed based on a survey of the composition and abundance of benthonic animal species.The research appraises water quality by applying multiple biological evaluation index,which provides supported data for Songhua river area water ecological system remediation.The main research results in this paper are as follows:Every September from 2015 to 2017,the survey were processed through five sampling positions in Songhua river Jiamusi section.Totally,30 samples of benthonic invertebrates were collected,identified 59 taxon benthic animals,belonging to 3 door 7classes to 42 families and 15 orders.Advantage species?advantage groups?are Heptagenia,Cheumatopsyche,Chironomidae,S.amurensis,and so on.Among them,Heptagenia and Cheumatopsyche are low resistance to pollution,so that both of them are signals of clean water.In the survey,both Heptagenia and Cheumatopsyche were found in abundance of sampling positions and place a majority position in community structure,dominance index are 0.065,0.149 respectively.The results suggested the water environment quality is generally favorable in the section.Community structure in Tangwang river estuary showed very similar among every year,extremely stable and great different from other sampling positions,based on the community structure cluster analysis and multidimensional scale ranking.But the community structure in Tangwang river estuary is significant different from other community structure of Jiamusi upper sampling position.The other three points communities located in downstream of the city have similar interannual community structure,with no obvious differenceever year.The results also showed that the community structure of large benthonic invertebrates relatively stable.From the water quality inspection results,the main pollution target of this section is total nitrogen?TN?in Jiamusi section of Songhua river,the concentration range is0.804².41 mg/L.The evaluation results of abiotic factors also meet the four types of water and above standards.Using redundancy analysis to study the relevance between benthic animal community and environmental factors.The result showed that the main factors changing community structure and species abundance were differences of various years.In 2015 and 2016 years,DO is the dominant factor influencing the change of community structure of large benthonic invertebrates,the concentration of BOD₅ was higher than the concentration of BOD₅ of in 2017 year.However,the major factors of the change of community structure of large benthonic invertebrates was BOD₅ in 2017year.Evaluation results showed of large benthonic invertebrates that the Jiamusi Songhua river locates between very clean and middle pollution range and no heavy pollution sampling positions.The water ecology comprehensive evaluation of benthic macrofauna and abiotic factors revealed that most sampling points is above light pollution level,then the evaluation grade of water ecology of individual section is health,which indicated that the water quality of this river section is really good.