Individual, population and community level effects of subtle anthropogenic contamination in estuarine meiobenthos. 
The study presented here searched for the level of taxonomic resolution required to detect the effects of low-level chronic pollution on estuarine meiobenthic communities.  Meiofauna from two sites, with special attention to harpacticoid copepods, was analysed at different taxonomic levels of aggregation using uni- and multivariate methods.  Adaptation processes that could buffer biodiversity disruptions were also considered through the analysis of fitness-related and tolerance traits in the harpacticoid copepod Paronychocamptus nanus.  Results showed that uni- and multivariate analyses could be inadequate when assessing subtle anthropogenic contamination.  Instead, the assessment of inter-population differences in tolerance to the main source of stress rises as a required procedure if potential effects of this type of contamination are being investigated.  Specifically, a 96 h acute toxicity test performed with populations from the affected site appears as a faster and reliable general tool to assess impacts of low-level chronic pollution in estuaries.