| The Huainan-Huaibei mining area had formed a large area subsidence area because of coal mining.Digou coal mining subsidence wetlands was caused by Huainan-Huaibei mining area coal mining subsidence of ground subsidence seeper and belonged to the national important wetlands,in the protection of national wetland park.This study took Digou coal mining subsidence wetlands as an example,research and investigation of subsidence basin of phytoplankton community composition and structure,understanding of various water quality factor(Total nitrogen,total phosphorus,ammonia nitrogen,nitrate nitrogen,chemical oxygen demand,chlorophyll a,pH,temperature,etc.)and the relationship between the phytoplankton community,its very important for mining subsidence wetlands as a special risk prediction,reasonable utilization of water resources,biodiversity conservation and ecological rehabilitation.According to the sampling survey of Digou coal mining subsidence wetlands in August 2015 to June 2016,phytoplankton community structure characteristics were studied,including species composition,dominant species,cell density,biomass,biodiversity index,In order to investigate the influence of wetland water body nutrient status of algae and the wetlands habitat types influence on phytoplankton biodiversity.Through redundancy analysis(RDA),analyzes the main environmental factor affecting phytoplankton community structure.The results showed that:1.A total of 155 species of phytoplankton were identified,which belong to 8 phyla,10 classes,17 orders,32 families and 62 genera in six sampling survey of 12 sites in Digou coal mining subsidence wetlands,mainly composed of cyanobacteria,chlorophyta and bacillariophyta,whilst chlorophyta species was most,a total of 59,accounted for 38.1%of phytoplankton species;Followed by the bacillariophyta species,a total of 47,accounted for 30.3%of phytoplankton species;Cyanobacteria species,a total of 18,accounted for 11.6%of phytoplankton species;And other algae species,a total of 31.From August 2015 to June 2016,the phytoplankton time dynamic of subsidence wetlands mainly marked by cyanophyta massive appearance and disappearance.In August of 2015,October and June of 2016,the main dominant species were Phormidium tenu and Oscillatoria amphibia;Chlorella vulgaris,Synedra ulna,Chroomonas acuta and Dinobryon sertularia dominated in December 2015 and February 2016.The variation range of the density and biomass of phytoplankton respectively was 22.68 × 105?22.68 × 105 cells/L and 2.47?7.41 mg/L.Algae overall trend of total density showed down first and then up,biomass variation trend and density fluctuation were similar,cell density and biomass of cyanobacteria dominanted during most of the survey period.2.The range of phytoplankton Shannon Wiener index(H')in Digou coal mining subsidence wetlands were from 1.09 to 3.68.The range of Margalef index(D)were from 0.39 to 2.10.The average range of Pielou index(J)were from 0.40 to 0.72.The study found that Shannon Wiener diversity index,Margalef abundance index and Pielou evenness index had spatial difference.The space difference of index was caused by different habitat types of mining subsidence wetlands,drainage communication and aquatic vegetation engraftment made the diversity of phytoplankton sound development.3.Redundancy analysis(RDA)in Digou coal mining subsidence wetlands,the relationship between phytoplankton and the main factors of water environment,the analysis results showed that the water temperature,total phosphorous,nitrate nitrogen and transparency were the important factors influencing phytoplankton community structure in the subsidence wetlands,and the water temperature is the key factor of phytoplankton temporal variation.4.Comprehensive nutrition state index and phytoplankton biomass showed that poor eutrophic state of subsidence wetlands.The water of Digou mining subsidence wetlands appear high nutrition and high temperature condition,and there was a potential risk of cyanobacteria bloom. |
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