| Compared to traditional physico-chemical monitoring methods for water quality, PFU method has many advantages, such as high efficiency and investigative speed and low cost. It has been widely used for pollution assessment and monitoring of freshwater environment. Three representative coastal water bodies in Qingdao were chosen as sampling sites and the structural and functional parameters of protistan communities were investigated separately in different seasons by modified PFU method– BPFU method. The present work assessed the pollution conditions of waters in combination with physical and chemical indexes in order to analyze the relationship between protistan community and water quality.Total 321 species of protists were observed during the whole survey period. Among them, there are 98 diatoms, 121 ciliates, 67 flagellates, and 35 sarcodina. The dominant groups of communities– ciliates were identified to genus or species by optical microscope and some species which tend to live in highly polluted waters were discussed as potential pollution bio-indicator.The results showed that structural parameters of three sites presented obvious seasonal change and spatial distribution. Total species number is the highest in autumn and it is the lowest in summer. In each season, total species number of site 1 is much higher than other two sites and there is no obvious difference between site 2 and site 3. The diversity index of site 1 and site 3 is the highest in autumn and it is the lowest in summer, which has the same trend as total species number. The diversity index of site 2 is the highest in spring, which is different with other sites. The diversity index of site 1 is usually higher than other two sites, which is also not obviously different from each other.Functional parameters of three sites also demonstrated their own seasonal change. The trend of spatial distribution showed that: species number during the equilibrium of colonization (Seq) of site 1 is higher than other sites which have no obvious difference except in spring. The constant value of colonization rate (G) of site 3 is the highest and the value of site 1 is the lowest. The time taken for reaching 90% Seq (T90%) has opposite trend with G value because T90% value is a parameter that is positively correlated with G value.This work showed that structural and functional parameters of protistan communities collected by BPFU systems coincided well with the water conditions at the main sites and could clearly differentiate their pollution levels. This study proves that BPFU method could be applicable for monitoring the pollution conditions of coastal waters and provides new solution ideas for biological assessment and monitoring of pollution status of seawater, and scientific foundations for general governance and improvement of marine water quality. |
