Benthic Diatom Communities of a Large Mediterranean River under the Influence of a Thermal Effluent

Abstract

The influence of a thermal discharge caused by the cooling system of a nuclear power station on benthic diatom communities was assessed at the lower Ebro River (in Spain), and the information generated could be useful to understand the effects of increasing temperature on large Mediterranean rivers. Surveys conducted at sites before and after the effluent and collected from natural and artificial substrate were analyzed and, Non-metrical Multidimensional Scaling (NMDS), Similarity Percentage Analysis (SIMPER) and 1-way Analysis of Similarities (ANOSIM) were performed to assess changes in community structure. The relationship between diatom assemblages and environmental variables was assessed with a multivariate distance-based linear regression model (DISTLM) and the model was visualized through a redundancy analysis (dbRDA). NMDS ordination was obtained with a stress of 0.18 and 0.17 for natural and artificial substrates, respectively...