| Urban water system is an important natural resource of a city,and its ecosystem function is of great significance to maintain the health of urban water ecosystem.However,under the dual pressure of urban population and social economy,some urban water ecosystems are facing threats such as water eutrophication,water shortage and water quality deterioration.At present,For typical urban water ecological system(rivers,lakes,wetlands)long-term focus of study is less,to objectively evaluate the typical water ecosystem,this study of jinan city as a study area,with typical characteristics of river water ecosystem(Xiaoqing River),lake water ecosystem(Daming Lake)and wetland water ecosystem(Jixi Wetland)as the research object,The annual phytoplankton,zooplankton and water environmental factors were investigated.The annual dynamic characteristics of plankton community structure were analyzed,and using canonical correspondence analysis(CCA)to identify the main drivers of plankton communities;Chemical comprehensive pollution index evaluation method,plankton diversity index evaluation method:Shannon-winner index(H'),Pieiou index(J),Margalef index(D)were used to evaluate the health of the typical aquatic ecosystem in Jinan city and analyze its countermeasures.The main results of this survey as follows:1.A total of 209 species of phytoplankton from 8 phyla were found in the annual survey of water ecology in Xiaoqing River,species are mainly composed of Chlorophyta,Bacillariophyta,the seasonal variation of species and density was higher in spring and summer than in autumn and winter,phytoplankton density for an average of 1.6926×10~7ind/L,The main dominant species in four seasons included Cyclotella meneghiniana,among which Cyanophyta appeared as the main dominant species in summer,including Phormidium tenus and Merismopedia minima etc,and eutrophication indicator species in spring and autumn included Scenedesmus,Melosira granulata etc.A total of 86 species of zooplankton were found in 4 phyla,species and density of both is given priority to with Rotifera and Protozoa,Copepods and Cladocera distribution is less,The average zooplankton density was 3.1629×10~2ind/L,and the seasonal variation trend of zooplankton density was the same as that of phytoplankton.Among them,Tintinnopsis wangi Nie mostly appeared in late autumn and early winter,As the dominant species,the pollution resistant species,such as Difflugia corona,Keratella cochlearis,Polyarthra trigla and Brachionus calyciflorus etc,were distributed in all seasons.Canonical correspondence analysis results showed that the most significant environmental factors affecting phytoplankton community structure in Xiaoqing River in spring were salinity,dissolved oxygen in summer,electrical conductivity in autumn,and water depth in winter.The most significant environmental factors affecting zooplankton community structure in spring were ammonia nitrogen and suspended solids,biochemical oxygen demand and PH in summer,PH in autumn,water temperature,biochemical oxygen demand and phosphate in winter.Chemical comprehensive pollution index evaluation results show that Xiaoqing River is in a moderate pollution state.According to the evaluation results of the three phytoplankton diversity indexes,Xiaoqing River was in?-moderate pollution state(H'),light pollution state(J),?-moderate pollution state(D).According to the evaluation results of three zooplankton diversity index,Xiaoqing River was in?-moderate pollution state(H'),light pollution state(J),?-moderate pollution state(D).Comprehensive judgment,Xiaoqing River is in?-medium pollution state.2.A total of 163 species of phytoplankton from 8 phyla were found in the annual survey of water ecology in Daming Lake,species are mainly composed of Chlorophyta,Bacillariophyta,between species and density of season for summer significantly higher than the other three seasons,phytoplankton density for an average of 6.6367×10~7ind/L,The density was much higher than that of Xiaoqing River and Jixi wetland with little difference of species,eutrophication degree is higher,among them,The density of Cyanophata was the highest,accounting for 57.47%,and Osillatoria minima and Osillatoria glauca were distributed in large quantities in four seasons.In summer,a large number of Cyanophata(warm-loving type)erupted,and the density was as high as 11.1334×10~7ind/L.Zooplankton found four phyla 62 species,species and density of both is given priority to with Rotifera and Protozoa,Copepods and Cladocera distribution is less,zooplankton density for an average of 6.2082×10~2ind/L,among them,the protozoa density is the highest,accounted for 80.62%,the density differences between seasons,winter density is significantly higher than the other three seasons,among them,As the main dominant species in winter,there was a large proliferation of Tintinnopsis wangi Nie and Tintinnopsis sinensis,and most of the water was dominated by pollut-tolerant species such as Brachionus diversicornis and Brachionus calyciflorus.Canonical correspondence analysis showed that the most significant environmental factors affecting the phytoplankton community structure in Daming Lake in spring were total phosphorus,transparency in summer,suspended matter in autumn,and ammonia nitrogen in winter.The most significant environmental factors affecting zooplankton community structure in Daming Lake in spring were permanganate,transparency in summer,total phosphorus in autumn and water depth in winter.Chemical comprehensive pollution index evaluation results show that Daming Lake is in a moderate pollution state.According to the evaluation results of three phytoplankton diversity indexes,daming Lake was in?-moderate pollution state(H'),light pollution state(J),?-moderate pollution state(D).According to the evaluation results of three zooplankton diversity indexes,daming Lake was in?-medium pollution state(H'),light pollution state(J),?-medium pollution state(D).Comprehensive judgment,Daming Lake in?-?pollution state.3.A total of 163 species of phytoplankton from 8 phyla were found in the annual survey of water ecology in Jixi Wetland,species are mainly composed of Chlorophyta,Bacillariophyta,species and density of seasonal changes in summer is higher than other three seasons,between phytoplankton density for an average of 9.3363×106ind/L,density mainly Chlorophyta,The density in summer and autumn is much higher than that in spring and winter,the proportion of Cyanophyta density increased in summer and autumn.From the point of view of dominant species,In summer and autumn,there were many Cyanophyta such as Phormidium tenus,Merismopedia minima,Merismopedia glauca,and other lean trophic species such as Dinobryon sertularia and Dinobryon divergens as the dominant species in spring and winter.The main dominant species in four seasons were mostly lean trophic species such as Achnanthes javanica,Scenedesmus spinosus and Ankistrodesmus falcatus etc.A total of 69 species of zooplankton were found in 4 phyla,species and density is given priority to with Rotifera,miniaturization of species composition,the seasonal variation of species composition was significantly higher in spring and autumn than in summer and winter,zooplankton density for an average of2.3826×10~2ind/L,Copepod mostly exist in the form of Nauplius,and Tintinnopsis wangi Nie most appeared in late autumn and early winter.Keratella cochlearis and Polyarthra trigla were the dominant species distributed in all seasons.Canonical correspondence analysis showed that the most significant environmental factors affecting the phytoplankton community structure in Jixi Wetland in spring were total phosphorus,biochemical oxygen demand,transparency in summer,permanganate index in autumn and water depth in winter.The evaluation result of chemical comprehensive pollution index shows that Jixi Wetland is clean and polluted.According to the evaluation results of three kinds of phytoplankton diversity indices,Jixi Wetland was in light pollution state(H'),clean state(J),?-medium pollution state(D).According to the evaluation results of three kinds of zooplankton diversity index,Jixi Wetland was in the light pollution state(H'),light pollution state(J),?-medium pollution state(D).Comprehensive judgment,Jixi Wetland in light pollution-?-medium pollution state.4.According to the comprehensive analysis results and the actual situation,the countermeasures and suggestions for the protection of the typical water ecosystem in Jinan city were obtained,For Xiaoqing River:improving the aquatic biodiversity,improving the ecological environment,ensuring the ecological base flow,and focusing on the way of"protecting the upstream and restoring the middle and downstream";For Daming lake:connection spring groups,Forming the annular water ecosystem of lake and Quancheng district,moreover,connecting the Xiaodong lake,the Xiaodong lake building as the"water purification ecological regulation pool",by raising the daming lake water self-purification ability,improve the ecological environment,water and its positioning for cultural,commercial,entertainment,city water ecological protection zone;For Jixi Wetland:Based on the ecological system structure and its own carrying capacity characteristics,the aquatic plant community restoration,with the original native plants as the main,moderately introduced as the auxiliary,fully reflects the natural ecological features of Jixi Wetland. |
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