| As the primary producer in the food web,the diversity and dominant species of algae is widely used to measure environmental change and water quality monitoring in wetland ecosystem.Urban wetlands roles a key component in ecological process,is closed relate to regulate urban microclimate,alleviate urban environmental pollution,and are rich in biodiversity.Jin Hewan Wetland is located on the left bank of the main urban area of Harbin City,Heilongjiang Province.The total area of Jin Hewan Wetland is 1.8 square kilometers.In these study,18 sample sites were set to collected algal samples in spring,summer and autumn in the Jin Hewan Wetland during 2017~2018.Meanwhile,the physical and chemical parameters of the water were monitored.According to the type of water in the Jin Hewan wetland,18 sample sites were divided into three types of water bodies,which include the Lake Wetlands,the River Wetlands,and Constructed Wetlands.The species composition,dominant species distribution and functional group succession of algae in the Jin Hewan wetland were studied.The temporal and spatial variation characteristics of algal community structure were analyzed.Based on the diversity index and cluster analysis to reveal the community structure.Meanwhile,the redundant analysis was performed to explore the correlation between environmental factors and algal functional groups.At the same time,the Jin Hewan water quality was evaluated comprehensively,which provide the basic information for wetland restoration and protection.The main findings include:1.The results of physical and chemical factors of the water were monitored in the Jin Hewan wetland showed that the mean water temperature(WT)was 18.70°C;the mean pH was 9.64,which indicated the water was alkaline;the mean of the specific conductance(SpCond.)was 227.19?s/cm;the mean concentration of total nitrogen(TN)was 1.52 mg/L;the mean concentration of total phosphorus(TP)was 0.35mg/L;the mean chemical oxygen demand(COD)was 25.72mg/L;The study found that the physical and chemical indicators were significantly different in time,and the spatial differences were not significant.The results of the Nutritional Status Index(TSI_M)showed that the water quality of the Jin Hewan wetland was generally in the middle nutrient-mild eutrophication state.2.During the study period,the algae community in the Jin Hewan wetland were investigated.A total of 221 classification units of algae were identified,which belong to8 phyla,11 classes,18 orders,35 families and 79 genera.There are 97 species of Chlorophyta,followed by 58 species of Bacillariophyta,37 species of Cyanophyta,20species of Euglenophyta,5 species of Dinophyta,2 species of Cryptophyta,and only 1species of Chrysophyta and Xanthophyta.In 2017,the mean phytoplankton abundance in Jin Hewan wetland was 29.87×10~6 ind./L,while 16.73×10~6 ind./L in 2018.3.The diversity index and diversity threshold(Dv)were performed to evaluate the water quality of the Jin Hewan wetland.The results showed that the range of Margalef diversity index(H)varied from 1.05 to 8.07;the Shannon-Weaver diversity index(H')was from 0.10 to 2.98;the Pielou evenness index(J)showed from 0.03 to 0.97;the range of Simpson?s ecological dominance(D)varied from 0.03 to 0.92;the range of diversity threshold(Dv)was from 0.03 to 0.92;Our results revealed that the water quality of the Jin Hewan wetland is in a state of clean and moderate pollution.4.During the study period,the Jin Hewan wetland was divided into 21 functional groups according to the classification of FG functional groups.In 2017,a total of 17functional groups were divided into B/C/D/E/H1/J/Lo/MP/N/P/S2/SN/TC/W1/W2/X1/X3;In 2018,20 functional groups were summed up,which refers to B/C/D/E/F/H1/J/Lo/M/MP/N/P/S2/SN/TB/TC/W1/W2/X1/Y.For functional groups that determine the succession of community structure,such as H1/TC/D/P/B,they can be regarded as indicator groups for the changes of water environment during the Jin Hewan wetland among different seasons.5.Based on cluster analysis to explored the community structure of the algal functional groups in the Jin Hewan wetland in 2017~2018,the results showed that the functional distribution of algae was effectively tools to reflected the classification of water types.The Q index in 2017 was ranged from 0.56 to 2.32,while from 1.02 to 3.77in 2018.According to the Q value,water quality in 2018 was better than that in 2017.6.The redundancy analysis(RDA)was used to analyze the correlation between the abundance of algae and the environmental factors in the Jin Hewan wetland.The results showed that water temperature(WT),chemical oxygen demand(COD),total phosphorus(TP),total nitrogen(TN)and Oxidation-Reduction Potential(ORP)affected the distribution of functional groups of algae together. |
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