2010年夏季雷州半岛海岸带浮游植物群落结构特征及其与主要环境因子的关系

Abstract

Phytoplankton are the most important primary producers in marine ecosystems and their distribution is influenced by environmental factors such as light,temperature,salinity,and nutrient availability,among others.The community structure and the spatial and temporal distribution of phytoplankton can reflect the characteristics of the environment.Leizhou Peninsula is located along the southern border of mainland China and is characterized by a winding coastline,numerous bays and islands,a wealth of marine biological resources and characteristic ecosystems such as coral reefs,mangroves,and seaweed beds,and so on.Interference from human activity has contributed to increased pollution levels in Leizhou Peninsula.To provide basic data for sustainable development of the economy and use of biological resources in the peninsula,the community structure of phytoplankton and the associated environmental factors were investigated in the coastal area of Leizhou Peninsula of Guangdong in the summer of 2010.Of the total 211 species(including distinct varieties and forms) from 76 genera of 7 phyla identified,143 species from 45 genera were Bacillariophyta,49 species from 15 genera were Pyrrophyta,13 species from 10 genera were Chlorophyta,3 species from 3 genera were Cyanophyta,and 1 species each was identified as Euglenophyta,Chrysophyta,or Raphidophyceae.Diatoms were predominant in the phytoplankton community in terms of species and biomass and 13 dominant diatom species were analyzed.Most of the dominant species were eurythermic and euryhaline,which is characteristic of a sub-tropical community structure along the seashore.Skeletonema costatum was the only dominant species that spread throughout the coastal area of Leizhou Peninsula.Phytoplankton species richness ranged from 10 to 59,and cell abundance varied from 1.25 to 1503.50 × 104 cells/L(averaging 131.76 × 104cells/L).Both phytoplankton species richness and cell abundance decreased from landward zone to seaward zone.In addition,the greatest abundance of species was observed in the southwest area,followed by the northwest area,south area,southeast area,and northeast area;however,the highest cell densities occurred in the northeast area,followed by the south area,southwest area,northwest area,and southeast area.The average diversity index and evenness of species exceeded 3.0 and 0.7,respectively,in the whole coastal area with the exception of the northeastern coastal area.Correlation analysis indicated that species richness of the phytoplankton was positively correlated with water temperature,Si/P,SiO2-3-Si,and Si/N,negatively correlated with NO-2-N and PO3-4-P,and not correlated with salinity,pH,surface chlorophyll a,DO,NO-3-N,NH+4-N,DIN,and N/P.Phytoplankton cell abundance was positively correlated to pH,surface chlorophyll a,DO,and NO-2-N,negatively correlated to salinity,and was not correlated to water temperature,NO-3-N,NH+4-N,DIN,PO3-4-P,SiO2-3-Si,N/P,Si/P,and Si/N.Furthermore,no correlation was found between phytoplankton species richness and cell abundance.Assessment of water quality according to the biological indicators of phytoplankton revealed that the quality was of middle-poor trophic type;however,according to nutrient indicators,the coastal area of Leizhou Peninsula was designated as nitrogen-limited mesotrophic or nitrogen-limited potential eutrophication.