Evaluation of Aquatic Ecological Health of Typical Lake in the River Network Area of Northern Zhejiang:A Case Study of Zhuxiyang Lake
Based on the lack of differential evaluation standards for aquatic ecosystems with different habitat characteristics,this paper took the lake aquatic ecosystem in the river network area of north Zhejiang plain as the starting point,adopted a set of lake aquatic ecological health evaluation system according to its functional structure and regional characteristics,and selected a typical lake to carry out aquatic ecological health evaluation research by evaluating 13 indicators of four essential factors including physical habitat,water quality,sediment and aquatic organisms.The results showed that the ecological health status of Zhuxiyang Lake,which is the largest lake in Deqing County,was sub-healthy.The large width ecological buffer zone and high vegetation coverage rate of Zhuxiyang Lake,created a good habitat condition for the conservation of biodiversity.Sufficient dissolved oxygen concentration,appropriate eutrophication degree and low risk of antibiotics,provided good water quality condition.However,high concentrations of total nitrogen and total phosphorus in the sediment of Zhuxiyang Lake,indicated a risk of endogenous pollution.A relatively high proportion of omnivorous fish,leading to a low diversity index of phytoplankton and zooplankton,revealed the imbalance and instability of Zhuxiyang Lake aquatic ecosystem.It is suggested that the breeding density of omnivorous fish should be appropriately reduced in fishery aquaculture of Zhuxiyang Lake to avoid excessive feeding on plankton.And corresponding measures should be taken to reduce the input of agricultural planting pollution and domestic pollution sources surrounding Zhuxiyang Lake,in order to control the cumulative risk of endogenous pollution in sediment.
aquatic ecological health evaluationtypical lakeplains river network areanorthern Zhejiang
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