ABSTRACT

Benthic diatoms are widely used as bio-indicators in water quality monitoring of rivers and streams, but less commonly in lentic waterbodies such as pools and lakes. Currently, a new method for assessing the ecological status of lakes is being tested in France to meet the requirements of the European Water Framework Directive (WFD) 2000/60/EC. This new method uses epilithic and epiphytic diatoms growing on stones and aquatic plants. Alternatively, freshwater turtles and the epizoic algae found on their carapaces may provide an excellent substrate for estimating water quality. Our study proposes an original diatom-based method for assessing the quality of water bodies in which turtles live. The main objective was to compare the Biological Diatom Index (BDI) values measured from epizoic diatom samples taken on the carapace of turtles with classical epilithic or epiphytic samples. Epizoic samples were taken from the carapaces of the turtle Emys orbicularis in two shallow French Mediterranean wetlands. Our results indicate that diatom assemblages differ slightly within the three substrates studied with limited variations in index value. However, some variability among epizoic samples from the same site suggests that several turtle individuals should be sampled for water quality biomonitoring.

抽象的

底栖硅藻被广泛用作河流和溪流水质监测中的生物指示剂，但在池塘和湖泊等大型水体中却很少使用。目前，法国正在测试一种评估湖泊生态状况的新方法，以满足欧洲水框架指令（WFD）2000/60 / EC的要求。这种新方法使用了生长在石头和水生植物上的表层硅藻和附生硅藻。另外，淡水龟和在其甲壳上发现的附生藻类可能为估计水质提供了极好的底物。我们的研究提出了一种基于硅藻的原始方法来评估海龟生活的水体的质量。主要目的是将在甲壳上采集的附生硅藻样品与经典附生或附生样品中测得的生物硅藻指数（BDI）值进行比较。从乌龟的甲壳中采集了生化样本Emys orbicularis在两个法国浅地中海湿地中。我们的结果表明，在所研究的三种基材中，硅藻的组合略有不同，并且折射率值的变化有限。然而，来自同一地点的生动物样本之间存在一定的差异性，这表明应该对几只乌龟个体进行水质生物监测。