Characteristics Of Phytoplankton Functional Groups In Dalihu Natural Reserve

To understand of phytoplankton functional groups and its seasonal and horizontal distribution characteristics in Dalihu Natural Reserve.The plankton community compositions and water chemistry indicators were investigated in Dalihu Natural Reserve in spring(May),summer(July)and autumn(September)of 2015 respectively.The lake included 8 sampling sites in Dalihu Natural Reserve.The aim of this study is to reveal the spatiotemporal distribution of phytoplankton functional group composition and their biomass,and also the relationship between the phytoplankton functional groups with environmental factors in high alkalinity water of northern cold area.The results showed that 35 species of phytoplankton and their variants were identified in the Dalihu Natural Reserve,and the bacillariophyta species were most,followed by the chlorophyta.The dominant species of phytoplankton in the three seasons of the Dalihu Nature Reserve are the Cyanophyta,The most dominant species of Merismopedia minima,which have the highest dominance in three seasons.Phytoplankton abundance showed obvious seasonal variation,which showed the characteristics of autumn> spring> summer.According to the international harmonized standard,the phytoplankton in the Dalihu Nature Reserve is divided into 13 different functional groups.According to the relative biomass ratio of at least one sampling point> 20%,there are seven dominant functional groups in the Dalihu Nature Reserve,namely Lo,H1,MP,P,C,X2,F.The seasonal variation of phytoplankton functional group was significant,and the seasonal variation of biomass group showed the characteristics of C+X2?H1+X2?Lo+X2 according to spring?summer?autumn.In the spring,the biomass of the sampling points in the summer was dominated by the functional groups X2 and H1,and the biomass 2# was the highest.The biomass of the sampling points in the autumn was higher than that in the other two seasons,mainly in the functional groups Lo and X2,and the biomass of the 5# sampling points was the highest,and the functional groups Lo,X2 dominant,2#,3#,4# and 8# sampling points to function group Lo dominant,7# sampling points to function group X2 dominant.The functional group X2 was the most of important phytoplankton functional group in cold region of Dalihu Nature Reserve,which indicated the habitat wetland was shallow water with moderate or high content of available nutrient and low content of filter feeding zooplankton.Factors affecting the phytoplankton functional group mainly include temperature,nutrient and hydrodynamics,but the main water environmental factors affecting the phytoplankton functional group in the Dalihu Nature Reserve are obviously different.The total alkalinity(ALK)is the most important factor affecting the phytoplankton functional group in the Dalihu Nature Reserve.Because the alkalinity is bigger of the Lake,it has the inhibitory effect on the growth of most algae.The total alkalinity(ALK)showing a significant negative correlation.Mercury(Hg)and arsenic(As)are the main influencing factors for the phytoplankton functional group,which have a strong inhibitory effect on most functional groups.Only MP function group showed strong adaptability.Because MP functional group mainly of Navicula,which is strong adaptability related to arsenic(As).The main influencing factors of water eutrophication in Darihu are water temperature and total phosphorus(TP).The growth of functional group H1 is related to temperature.The growth of functional group Lo and X2 is related to total phosphorus(TP).Total nitrogen(TN)had little effect on the phytoplankton functional group.According to the phytoplankton biomass,the dominant phytoplankton functional groups and Q index of phytoplankton functional groups,the Dalihu Nature Reserve in the seasons of the sampling points as a whole in the light pollution state,but only shows the situation of water nutrient,And did not reflect the heavy metal pollution in the water situation.This article embarks from the biomass,illustrated the phytoplankton functional group composition and the spatial and temporal distribution characteristics,and also the relationship between the functional groups and environmental factors in the typical wetlands of the Dalihu Nature Reserve.We also evaluated the pollution state of Dalihu Nature Reserve using the Q pollution index basing on phytoplankton functional groups.According to the situation of heavy metal pollution in the water body and the evaluation result,the deficiency of the biological evaluation was supplemented,which provided the basic data for the biological evaluation of the water environment.