The Seasonal Dynamics Of Phytoplankton Ecological Groups And Its Influencing Factors In Dianshan Lake, China

This study of Dianshan Lake (including Yuandang Lake) have 12 sites as the research sample, in January to October 2015, during season as the time scale for collection of phytoplankton, zooplankton, and have a field testing and indoor experimental study within the sample for the physical and chemical indexes. Using the chi square test and the analysis of the Pearson correlation coefficient test link and interrelation between phytoplankton species. At the same time, we will through factor analysis, combined with the correlation between phytoplankton, and divide phytoplankton ecological species group, so that we can have a further study of Dianshan Lake phytoplankton community structure. Pearson correlation analysis between ecological Phytoplankton species group and environmental factors (physical and chemical factor, biological factor), to explore the environmental factor driving action of phytoplankton ecological species group. This study in the perspective of ecology of phytoplankton community, summed up the phytoplankton ecological species group dynamics in season, and explores the role of phytoplankton dynamics of environmental factors driving. This study has an important meaning to the further understanding of phytoplankton dynamics in Dianshan Lake, and providing a valuable reference for Dianshan lake recovery. The main results were as follows:1. During the 2015, annual average temperature of Dianshan Lake is 19.39℃, annual change in the range of 7.30～29.10℃. Light attenuation coefficient average of 2.33, annual range of 0.59～4.67. PH year average of 8.62, its weak alkaline, range of 6.82-11.97. Dissolved oxygen average of 7.15 g/m3, annual and the range is 0.54～ 12.35 g/m3, volatile throughout the year. Transparency with a mean of 0.63 m, the year SD range from 0.37～1.80 m. Conductivity average of 619.58 us/cm, annual range from 478.00～969.00. Total phosphorus average of 0.06 mg/L, annual range of 0.03～ 0.13 mg/L, the four seasons average sort of summer> autumn> spring> winter. Total nitrogen average of 3.10 mg/L, the range of 0.14～6.47 mg/L, all the year round the value sorting for the winter> spring> autumn> summer, the four seasons have larger fluctuation.There were 38 species of zooplankton 3 door are identified, among them,15 kinds of rotifers, Cladocera class 14,9 kinds of copepods. The number of species is summer> autumn> spring> winter. Zooplankton density for an average of 1510 single/L throughout the year, annual change in the range of 430～2804 single/L. The average range of Biomass in 0.0003-22.1780 mg/L, the highest average biomass is Sinocalanus dorrii, the second is Mesocyclops leuckarti.2. During the 2015, identification of phytoplankton 210 species belonging to 80 genera and 8 class (including variant, variant), of which the Chlorophyta 40 genera and 98 species, Bacillariophyta 18 genera and 49 species, Cyanophyta 9 genera and 27 species, Euglenophyta 5 genera and 27 species, Pyrrhophyta 3 genera and 5 species, Cryptophyta 2 genera and 4 species, the Chrysophyte 2 genera and 2 species,1 kind of Xanthophyta 1 genus. Annual species was summer> spring> autumn> winter. Sort the mean density of the four seasons of autumn> summer> spring> winter, the average density of 31.4 x 106 cells/L. The average chlorophyll is 24.1 mg/cm3, annual range is 3.1 mg/cm3～50.2 mg/cm3, then four quarters between mean is spring> winter> summer> autumn.3. During the investigation, the spring phytoplankton species overall coupling test show that the interspecific relationship is positive connection (VR= 1.08), but not significant; the 24 kinds of phytoplankton is divided into six main ecological species group. Summer phytoplankton species overall coupling test show that the interspecific relationship is positive connection (VR=2.50), the overall coupling significantly; The 26 kinds of phytoplankton in summer is divided into eight ecological species group. Autumn phytoplankton species overall coupling test show that the overall interspecific relationship is positive connection (VR= 0.91), the overall species was not significant; The 14 kinds of phytoplankton in autumn is divided into six main ecological species group. The overall coupling test of phytoplankton species in winter showed that the overall interspecific relationship is positive connection (VR= 2.82), the overall coupling significantly; The 22 kinds of phytoplankton in winter is divided into seven ecological species group.4. Spring ecological species group is given priority to with green algae, diatoms-algae, all sorts of group are positively correlated with physical and chemical factors, the main influence factors is the conductivity, dissolved oxygen and chla; The kind of group is given priority to with blue-green algae-diatom-green algae in summer, temperature is a major factor driving between groups of phytoplankton growth, conductivity is part of a group of limiting factors; Autumn group is given priority to with green algae, cyanobacteria, pH is the main impact factor; Winter is given priority to with green algae, relationship between groups and environmental factors is relatively scattered, appeared on the conductivity of adaptive opposite groups, each group have a differentiation is more obvious.5. Chroomonas acuta are dominant species in the investigation. Kd is the main physical and chemical factors affect the group. These species also has good tolerance for Kd that with Chroomonas acuta same group.