Phytoplankton assemblage classification in Anbang River wetland in summer

An investigation on the phytoplankton was carried out in Anbang River wetland from ten localities in summer 2005. Phytoplankton species composition and assemblage classifications were analyzed by multivariate analyses, including cluster analysis and metric multidimensional scaling analysis (MDS). A total of 82 species was found, belonging to Chlorophyta (44), Cyanophyta (19), Bacillariophyta (12), Xanthophyta (2), Chrysophyta (2), Cryphophyta (2), and Euglenophyta (1). The average abundance was 268.45104 indL-1, and the predominant phytoplankton species were Anabaena sp., Merismopedia glauca, Microcystis aeruginosa, Cyclotella meneghiniana, Fragilaria capucina, and Pediastrum tetras. Based on the Bray-Cartis similarity matrix calculated according to species abundance of each locality, hierarchical cluster and MDS analysis showed that three assemblages can be distinguished and named by representative and dominant species: (i) Anabaena sp.-Microcystis aeruginosa-Cyclotella meneghiniana assemblage (AMC), with representative species of Anabaena sp., Aphanizomenon flos-aquae, Microcystis aeruginosa, Cyclotella meneghiniana, Synedra acus, Chlamydomonas olifanii, Scenedesmus arcuatus, Scenedesmus bijuga, and Cryptomonas marssonii, located in coast, (ii) Pediastrum tetras assemblage (PPP) in the center of wetland with representative species of Pediastrum boryanum, P. tetras, Staurastrum crenulatum, and Xanthidium sp., and (iii) Merismopedia glauca assemblage (MMM), with representative species of Merismopedia glauca, Chromulina pascheri, Closterium gracile, Cosmarium sp., Hyalotheca dissiliens, and Pediastrum biradiatum in the lotus flower pond. The representative species of phytoplankton in each locality demonstrated the differentiation of nutrition in sampling localities, thus associating with the geographical locations.