Browsing by Author "Coelho, Susana Isabel Eusébio"
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- Environmental conditions and biotic communities in Foz de Almargem and Salgados coastal lagoons, Algarve (South Portugal)Publication . Coelho, Susana Isabel Eusébio; Gamito, Sofia; Pérez-Ruzafa, AngelThe present study intended to compare environmental conditions and biotic communities of two choked coastal lagoons located in the Algarve region, Foz de Almargem and Salgados, with the purpose of evaluating the effects of organic pollution from wastewater discharges in water quality and biotic communities from different levels of the food chain, namely phytoplankton and benthic macroinvertebrates. Both lagoons were seasonally connected to the sea, but most of the year they were isolated receiving the freshwater input from small rivers and wastewater (in Salgados). Data were collected from June 2001 to July 2002 in three sampling stations, according to a gradient of proximity with the sea. Characterization of environmental conditions was performed based on the study of hydrological parameters, physical and chemical water parameters, and sediment parameters. Phytoplankton communities were analyzed in terms of phytopigments concentrations; taxa composition, richness, abundance, diversity and salinity tolerance. Relations between phytoplankton and water parameters were analyzed through bivariate and multivariate statistical techniques. Results indicated that the two lagoons presented different phytoplankton communities, which were associated to water parameters and particularly with organic pollution in the case of Salgados lagoon. Taxonomic composition, richness, abundance and diversity of benthic macroinvertebrate communities were also characterized, just as ecological features concerning the salinity tolerance of taxa, trophic groups and sensitivity to an increasing stress gradient. Relations between benthic macroinvertebrate parameters, water and sediment parameters were analyzed with the same techniques used with phytoplankton. Results also revealed distinct benthic macroinvertebrate communities in Foz de Almargem and Salgados lagoon, which were related with the environmental parameters that indicated a greater organic pollution in Salgados lagoon. Water quality and trophic state were evaluated using different indices and approaches that classified Salgados lagoon as a hypereutrophic system with bad water quality. Most indices pointed out to mesotrophic conditions in Foz de Almargem, although they were not always concordant.