MOLECULAR DIVERSITIES OF PLANKOTIC MICROBIAL EUKARYOTES IN THE PEARL RIVER AND THEIR RELATIONSHIP WITH WATER ENVIRONMENT

To analyze the molecular diversity of planktonic microbial eukaryotes as well as relationships between the community structures and physicochemical factors based on the terminal restriction fragment length polymorphism (T-RFLP), water samples were collected from 43 sites in Guangzhou Reach of Pearl River and Guangdong Reach of Xijiang River during wet season and dry season, respectively. The results revealed that water bodies of Guangzhou Reach of Pearl River and Guangdong Reach of Xijiang River were seriously polluted by nitrogen and phosphorus, and the water were in poor quality. The diversity indexes of planktonic microbial eukaryotes in Guangdong Reach of Xijiang River were higher than those in Guangzhou Reach of Pearl River. The Shannon-Wiener indexes of samples collected in wet season were lower than those in dry season. There were significant differences in community structures of microbial eukaryotes from different seasons and regions. The community structures of planktonic microbial eukaryotes in Pearl River were affected by chemical oxygen demand, permanganate index, ammonia nitrogen, total nitrogen and total phosphorus. However, correlation coefficients between community structures and physicochemical factors were different depending on seasons and regions. In addition, one T-RF and six T-RFs were selected as possible sensitive species (Cystobasidium sp. or Protostelium nocturnum) and pollution-tolerant species (Acanthamoeba hatchetti, Babesia bicornis, Blastocystis sp., Botryosphaerella sudetica, Candida caryicola, Coccomyxa simplex, Cryptomonas ovata, Filos agilis, Stenophora robusta, Sulfonecta uniserialis and Theileria sp. etc.), respectively.