Bioindicators are organisms that rapidly reveal the quality of an environment, by highlighting the effect of environmental changes on a population, community, habitat or even on an ecosystem [1]. On the basis of this characterization, bioindicators are useful in assessing additive, synergistic and antagonistic effects upon living organisms within a broad pollutant-based spectrum of complex environments [1] and [2]. In the last few decades, several bioindicators for freshwater environments have been thoroughly studied. Most of these organisms are macrobenthic invertebrates, algae and microorganisms [3], [4] and [5]. Depending on the type of organism chosen, there exist a variety of scales that can be examined by biomonitoring: individual, multi-population and community-related [1], [6] and [7]. For example, aquatic macroinvertebrates can be considered sensitive sentinels in polluted freshwater; analyses show they can be recorded at different ecological levels. The response at the individual level is usually linked to a defined type of pollution stress. In contrast, a multi-population examination is slightly more difficult to understand, since it requires more exhaustive testing due to the complexity of additional sources of disturbance [8].
Materials and methods
Introduction
Results and discussion
Bacterial community structures as a diagnostic tool for watershed quality assessment