Division Of Phytoplankton Functional Groups In Coastal Freshwater Wetlands

The phytoplankton samples and environmental factors were investigated seasonally in Beidaihe national wetland park from April 2017 to November in 2017,as a representative of coastal freshwater wetlands.25 sampling sites were set up in different water areas as rivers,drainage ditches and ponds.The phytoplankton functional groups were divided according to the environmental factors and circumstances of the sampling sites.Water quality was evaluated on the basis of the comprehensive nutrition index,biodiversity index and phytoplankton functional groups Q index.Compatible patterns to divide the phytoplankton groups and background information and references for the management of Beidaihe national wetland park were the purposes of the survey.232 species or genera of phytoplankton were identified belonging to 8 families,among which 90 species(genus)of Bacillariophyta,accounting for 39% of total of total phytoplankton species;76 species(genus)of Chlorophyta,accounting for 33% of total phytoplankton species;19 species(genus)of Cyanophyta,accounting for 8% of the total phytoplankton species;19 species(genus)of Euglenophyta,accounting for 8% of total phytoplankton species;12 species(genus)of Pyrrophyta,accounting for 5% of total phytoplankton species;8 species(genus)of Chrysophyta,accounting for 3% of total phytoplankton species;7 species(genus)of Cryptophyta,accounting for 3% of total phytoplankton species;1 species(genus)of Xanthophyta,accounting for less than 3% of total phytoplankton species.The results suggested that the dominant species pertained to Bacillariophyta and Chlorophyta in Beidaihe national wetland park in the period of the investigation,for instance Cyclotella meneghiniana and Chlorella vulgaris.During some seasons the dominant species pertained to Cyanophyta,Euglenophyta and Cryptophyta,for instance Chroococcus tenax,Trachelomonas curta,Trachelomonas euch Lora and Cryptomonas ovata.Abundance of phytoplankton was different in different season,and the dominant phytoplankton community were Bacillariophyta,Chlorophyta and Cyanophyta during the period of the investigation.The abundance of Bacillariophyta and Cryptophyta in spring and winter was visible higher than it in summer and autumn,and the abundance of Chlorophyta,Cyanophyta and Euglenophyta were on the opposite.On the spatial,the abundance of phytoplankton in the sampling sites in drainage ditches and ponds far from the coast was large than others.The Shannon-Wiener diversity index of phytoplankton ranged from 1.093-3.483.On the temporal,the seasonal Shannon-Wiener diversity index of phytoplankton was steady besides it in autumn.On the spatial,the average of it in sites S11 was lower than others.The Margalef index ranged from 0.777 to 3.671.On the temporal,the Margalef index in spring was lower than others.On the spatial,the average of Margalef index in S2 was lower than others.Pie Lou evenness index ranged from 0.354 to 0.932.On the temporal,the Pie Lou index in spring was higher than others.On the spatial,the average of it in S7 was higher than others and the average of Pie Lou index in S11 was lower than others.The phytoplankton functional groups was divided in accordance with the way of FG.In total,14 phytoplankton functional groups was classed in the area of the investigation.7 functional groups was distinguished in spring,11 functional groups was distinguished in summer,11 functional groups was distinguished in autumn,10 functional groups was distinguished in winter.The functional groups such as D,W2,X1,X2,were identified in all the time,and B was only occurred in winter.The changes of phytoplankton functional groups were significant at each sampling site on spatial and temporal.The abundance of phytoplankton functional groups accounted for the lowest proportion in spring and that accounted for the largest proportion in winter.On the spatial,the abundance of phytoplankton functional groups accounted for the lowest in S7,and that in S11 was the highest.The water quality was evaluated.The comprehensive index,Shannon-Wiener index,Margalef index and Q index showed that the waters were from medium eutrophication to severe eutrophication.But the Pie Lou index showed that the waters were in situation of light pollution or no pollution.In summary,the waters in the surveyed areas were in state of medium eutrophication-severe eutrophication.The redundancy analysis(RDA)suggested that the relationship between phytoplankton functional groups and environmental factors was complicated.The phytoplankton functional groups were positive correlation with nutrients,Chl-a,SD and DO in spring;the phytoplankton functional groups were positive correlation with TN,NH4+-N,WT,COD,Chl-a and pH in summer;the phytoplankton functional groups were positive correlation with TN,NH4+-N,WT,SD and COD;the phytoplankton functional groups were positive correlation with pH and COD.