Pollution de l’environnement et changement climatique

Abstrait

Use of Protozoa for Assessing Water Quality in a Humid Subtropical Urban Wetland Ecosystem, Southern China

Cuicui Hou, Xinlu Shi, Guijie Liu, Songlu Liu, Xiaowen Zhu, Henglong Xu

Multivariate bioassessment based on community data has many advantages to assess environmental quality status in aquatic ecosystems. However, there are few reports on their use for bioassessment in subtropical wetland systems. In this study, the protozoan microfauna and their use in evaluating water quality status was investigated in a humid subtropical urban (XiXi) wetland system in southern China, during the period of June 2013-May 2014. Samples were collected every month at six sampling stations within different pollution/eutrophication levels. A total of 85 protozoan species were recorded, including 67 ciliates, 10 flagellates, 8 sarcodines. A clear variation on spatial scale in protozoan community structures were represented at the six stations. Multivariate approaches revealed that the variations in the community structure were significantly related to the changes of environmental variables, especially nutrients ammonia-N (NH₄-N), nitrate-N (NO₃-N) and total phosphorus (TP), alone or in combination with water temperature (T) and dissolved oxygen (DO) and Four dominant species (Euglena acus, Cucurbitella mespiliformis, Codonella acutula and Hemiophrys punctata) were significantly correlated with nutrients. Otherwise, the species richness, diversity and evenness indices represented significant correlations with the nutrients. The results demonstrate that the community-based bioassessment using protozoa may be used as a feasible protocol for determining the water quality status and human disturbance in a humid subtropical urban wetland system.