title: Use of ciliates (Protozoa: Ciliophora) as bioindicator to assess sediment quality of two constructed mangrove sewage treatment belts in Southern China.
abstract: To complement physical and chemical data, information of biological communities is important to assess the qualities of mangrove sediments receiving wastewater. Ciliate communities have cosmopolitan distribution, short life cycle and high sensitivity to pollutants, which make them useful as biological indicators of the sediment environment. In most literature, ciliates are widely used as bioindicators for the state of water quality. In this study, the physico-chemical parameters and ciliate community structure of surface sediment collected at different sampling points from two constructed mangrove (Aegiceras and Sonneratia) belts for treatment of municipal sewage in southern China were investigated. Results showed that most (> 80%) of the 216 species ciliates identified at the two constructed mangrove belts were either omnivorous or bacterivorous. Sediment redox potential (Eh) was considered an important factor to govern the distribution of ciliate species within the mangrove sediment. The saprobic system originally derived from freshwater ecosystem was used to evaluate the saprobic degrees of these constructed mangrove belts. Saprobic index (SI) values declined from the sewage inlet to the outlet points of the constructed belts, suggesting better sediment quality at the outlet point caused by treatment processes within the mangrove belt system. Sediment quality of the sewage outlet area of the constructed Aegiceras belt was determined as class II-III (SI = 2.48), while that of the Sonneratia belt was as class III (SI = 2.71) according to the saprobic classification, indicating that a better sewage treatment efficiency was apparent in the Aegiceras than Sonneratia belt. The present data suggested that ciliates could serve as a good bioindicator in assessing organically polluted sediment qualities.
authors.affiliation: School of Life Sciences, Zhongshan University, Guangzhou 510275, China.
authors.forename: Qing-Hua
authors.initials: QH
authors.lastname: Chen
authors.forename: Run-Lin
authors.initials: RL
authors.lastname: Xu
authors.forename: Nora F Y
authors.initials: NF
authors.lastname: Tam
authors.forename: Siu Gin
authors.initials: SG
authors.lastname: Cheung
authors.forename: Paul K S
authors.initials: PK
authors.lastname: Shin
mesh_terms: D000818:Animals; D044822:Biodiversity; D002681:China; D016798:Ciliophora / Q000187:drug effects* / Q000502:physiology; D016000:Cluster Analysis; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D019684:Magnoliopsida; D012623:Seawater / Q000737:chemistry; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods / Q000592:standards; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D053833:Wetlands
chemical_list: D012722:Sewage; D014874:Water Pollutants, Chemical