The Features Of Phytoplankton Community And Relationship With Environmental Factors In The Yellow Sea In Spring,2014

The survey of phytoplankton in the Yellow Sea (120.99°～125.16°E,31.20°～39.23°N)was taken by the voyage since 28th, April to 18th May in 2014.173 samples were obtained by 40 stations,and 185 taxa in 81 genera of 7 phylum of phytoplankton was diagnosed by using Utermohl method in the lab. In the vertical distribution of phytoplankton, we found that the cell abundance has a maximum in the surface and subsurface layers. The phytoplankton cell abundance of surface layer peaks in the West of Korea Peninsula and the offshore of south of Liaodong. The phytoplankton in these area is mainly composed of diatoms and cyanobacteria, with the main dominant species as Cylindrotheca closterium, Synechocystis pevalekii, Chroomonas acuta, Par alia sulcata, Thalassiosira pacifica and Karenia mikimotoi etc. By analyzing the water temperature and salinity combined with the depth of the stations, the Yellow Sea is divided into 5 provinces, and the phytoplankton community of entire area and each district were analyzed and compared. The station of Provinces I (P-I) is on behalf of the southern Liaodong Coastal stations. The cell abundance of total phytoplankton is between 35419.815 X 103cells/Land 36162.634 X 103 cells/L, with average of 35791.225 × 103 cells/L.99.84% of the total phytoplankton biomass is contributed by cyanobacteria, with the dominant species as Synechocystis pevalekii; the station of Provinces Ⅱ (P-Ⅱ) represents for the Yellow Sea Western Coastal stations. The cell abundance of total phytoplankton in P-II is between 2.007 X 103 cells/Land 48.230 X 103 cells/L,with average of 23.870×103 cells/L.63.69% of the total phytoplankton biomass is contributed by diatoms, with the dominant species as Thalassiosira pacifica; the station of Provinces III (P-III) stands for the Yangtze River diluted water. The cell abundance of total phytoplankton in P-III is between 10.110 X 103 cells/L and 37.306 × 103 cells/L,with average of 23.708 X 103 cells/L.73.14% of the total phytoplankton biomass is contributed by diatoms, with the dominant species as Skeletonemacf. costatum; the station of Province IV (P-IV) represents for the aera affected by the Yellow Sea warm current. The cell abundance of total phytoplankton in P-IV is between 5.750 X 103 cells/Land 82.071 × 103 cells/L, with average of 27.293 X 103 cells/L.64.17% of the total phytoplankton biomass is contributed by diatoms, with the dominant species as Thalassiosira pacifica; the station of Province V (P-V) is on behalf of the cold water mass of the Northern Yellow Sea. The cell abundance of total phytoplankton in P-V is between 41.302 X 103 cells/Land 8912.301 X 103 cells/L,with average of 1763.332 X 103 cells/L.89.96%of the total phytoplankton biomass is contributed by diatoms, with the dominant species as Cylindrotheca closterium; considering the section distribution, the region with high value of phytoplankton cell abundance concentrates in the surface layer both of coastal stations and the Yellow Sea warm current. The Shannon Wiener diversity index of the phytoplankton community in the surface layer is from 0.009 to 3.984, with the average of 1.889; the Pielou evenness index is between 0.002 and 0.946, with the average of 0.493. Overall, the phytoplankton community structure in the Southern Liaodong Peninsula, Northern Shandong-Chengshan Corner area, the western area of Korean Peninsula and Subei Coastal Zone is relatively stable.Canonical correspondence analysis (CCA) was applied to explore the relationship between phytoplankton species and environmental factors using MVSP 3. The biplot showed the relationship between dominant species and environmental factors. The main environmental factors affected the distribution of the phytoplankton in the Yellow Sea in spring was temperature and salinity.