Research On Distribution Pattern And Environmental Relevance Of Phytoplankton Functional Groups In Daqing Longfeng Wetland

As the main primary producer in the water ecosystem,the phytoplankton community pattern is closely related to the material circulation,information transmission and energy flow of the water body.Its distribution pattern is often used to indicate the environmental characteristics of coastal intertidal zones,rivers,wetlands,lakes and reservoirs and community succession model prediction.In this study,phytoplankton sammples were collected afrom 24 sampling sites in the Daqing Longfeng Wetland in spring,summer,and autumn in 2019 and autumn in2020.At the same time,physical and chemical parameters of the water were measured at collection time.Based on the information from the China Remote Sensing Data Network and field observations during the collection,the 24 sampling points of the Daqing Longfeng Wetland are divided into five areas,including the water inlet area,the upstream lake wetland area,the wetland protection area,the wetland residential area and the water outlet area.The species composition,distribution of dominant species,cell abundance,three functional groups of FG,MFG,MBFG and the succession law of C-S-R growth strategy of phytoplankton in Daqing Longfeng Wetland were studied,and the temporal and spatial distribution pattern of phytoplankton community structure was explored.At the same time,based on environmental factors,using the"Q"index and RDA redundancy analysis method,the relationship between environmental factors and the three functional groups of FG,MFG and MBFG was discussed,and the biodiversity index was used to determine the water environment of the Longfeng Wetland.The comprehensive evaluation is expected to provide a theoretical basis for the protection of the biodiversity of the Longfeng Wetland and the restoration of the damaged wetland ecosystem.The main results are as follows:1.The phytoplankton in Daqing Longfeng Wetland was surveyed in spring,summer and autumn in 2019 and autumn in 2020.A total of 209 taxa of phytoplankton were foundwhich belonging to 7 phyla,10 classes,and 18 Orders 35 families and 79genera.Among them,the Chlorophyta has the largest number of species,followed by Bacillariophyta,Cyanophyta and Euglena,and other phytoplankton species are relatively rare.The average abundance of phytoplankton in Daqing Longfeng Wetland in 2019 are 5.18×10~6ind./L,and the average abundance of phytoplankton in 2020 are1.95×10~6ind./L;phytoplankton abundance has obvious temporal and spatial distribution characteristics.In Daqing Longfeng wetland phytoplankton,55 taxa of dominant species were discovered in two years.Among them,there are many species of Chlorophyta,Cyanophyta and Bacillariophyta,and the dominant species are heterogeneous in each region.2.In the autumn of 2019 and 2020,the average water temperature of Daqing Longfeng Wetland is 16.51?and 18.06?,and the variation range is between4.10-27.20?;the average p H is 8.52 and 7.95,and the variation range is between7.49-9.29;the average conductivity is 1377.75pectively It 8.52 and the range is between 190.20-3999.00?the;the average dissolved oxygen is 7.68mg/L and9.16mg/L,the range is between 1.10-17.46 mg/L;The average turbidity is 35.67NTU and 58.25NTU,and the range is between 4.50-200.00 NTU;the average total nitrogen is1.57mg/L and 0.80mg/L,and the range is between 0.76-2.39 mg/L;the average total Phosphorus was 0.47mg/L and 0.48mg/L,and the variation range was 0.10-2.04 mg/L;the average permanganate index was 10.82mg/L and 13.63mg/L,and the variation range was 4.45-18.47 mg/L;the average five-day biochemical oxygen demand is 3.27mg/L and 4.21mg/L,and the range of variation is between 0.40-15.53 mg/L.One-way analysis of variance showed that the physical and chemical indicators of the water in Daqing Longfeng Wetland have significant differences at different time.The comprehensive nutritional status index(TSI_M)was used to evaluate the water bodies.The nutritional status of the water bodies in different regions was different.The water quality of the Daqing Longfeng Wetland in was generally in a moderately eutrophication state.3.According to the biodiversity index Shannon-Weaver(H'),Margalef(H),Pielou(J)and the diversity threshold(Dv),he water quality evaluation of Daqing Longfeng Wetland in the autumn of 2019 and 2020 was carried out,and the results obtained were slightly different.In terms of time,the highest average of H and H'values occurs in summer,the lowest average value occurs in spring,the highest average value of J and D values occurs in spring,and the lowest average value occurs in autumn;spatially,H,H',The highest average value of J and D values mostly occurs in the water outlet area.The average values of H,H',J and D in the water inlet area and the wetland residential area are at the lowest level.The Margalef diversity index,Shannon-Weaver diversity index,and Pielou uniformity index were used to evaluate the water quality of Daqing Longfeng Wetland in the autumn of 2019 and 2020.The results were shown as follows:he Marga pollution status,clean to?pollution status,clean to,Shannon-Weaver diversity index,and Pielou uniformited that phytoplankton had a relatively stable community structure during the study period;the evaluation results of water quality using the diversity threshold showed that the water body was at level I as a whole;in2019 and autumn of 2020,the water body of the Longfeng Wetland in Daqing showed a state of light to medium pollution.4.A total of 22 FG functional groups have been divided in two years,namely B/C/D/E/F/G/H1/J/L0/LM/M/MP/N/P/S1/S2/W1/W2/X1/X2/X3/Y groups,20 MFG functional groups,3a/5a/6a/7a/8a/9a/10a/11a/1b/3b/6b/9b/11b/1c/2c/6c/11c/There were 6 groups of 2d/5d/5e and MBFG functional groups,?/?/?/V/?/?groups respectively.In the past two years,15 FG advantageous functional groups were divided into B/C/D/G/F/J/M/MP/P/S1/S2/W1/X1/X2/Y groups,and 16 MFG advantageous functional groups were divided into 5a/6a/7a/8a/9a/10a/11a/1b/3b/7b/9b/11b/6c/2d/5d/5e,and there are 6 MBFG dominant functional groups,?/?/?/V/?/?respectively.The three functional groups of phytoplankton in Daqing Longfeng Wetland and the CSR strategy had a certain seasonal distribution pattern,but the spatial distribution pattern is not obvious.Based on the results of the Q index analysis,the average Q index in the fall of 2020 was slightly greater than that in the fall of 2019,and the Q indexes were both greater than 1.The evaluation result is that the water quality in the fall of 2020 was slightly better than that in the fall of 2019.A small number of sampling points were in good condition.5.The succession and spatial distribution pattern of phytoplankton functional groups in Daqing Longfeng Wetland are closely related to the spatial heterogeneity of environmental factors.Based on the results of redundancy analysis and Pearson correlation analysis,the main environmental factors affecting the succession and distribution of the three functional groups of FG,MFG,and MBFG in the Daqing Longfeng Wetland were:water temperature(WT),permanganate index(CODMn),conductivity Rate(Sp Cond.).According to Pearson's correlation analysis,DO and BOD5 were extremely significantly positively correlated.The increase in organic pollution and eutrophication in the water body lead to a decrease in dissolved oxygen in the water.