Changes in the Fatty Acids Profile of the Zooplankton Community Reveals the Quality of Four Reservoirs in the Hydroelectric Power Plants Located in the Iguaçu River, Paraná, Brazil

Abstract

Fatty acids are molecules with important physiological functions, proved to be good bioindicators of the presence of natural and chemical stressors and so used as early warning signals. Indeed, biochemical analyzes, such as fatty acids, are an important tool in water body management and water quality analysis, allowing detecting molecular changes in aquatic communities, related to the trophic status of the systems, before they are perceived in the environment. In this work was investigated the fatty acid composition on zooplankton community collected in four reservoirs of hydroelectric plants on the Iguaçu River, Brazil, and assessed the species distribution to assess and compare the water quality in these reservoirs. Results showed the trophic state index presented a wide variation among samples, ranging from oligotrophic (Salto Caxias) to hypereutrophic (Foz do Areia). The most abundant fatty acid was docosahexaenoic acid (DHA, C22:6n3) an essential fatty acid with health benefits, playing a pivotal role in biological functions. This study highlights the sensitiveness of the zooplankton community to environmental conditions and underlines the role of fatty acids as good bioindicators, being good endpoints to use in ecological studies. This supports the zooplankton contribution as a biological quality element in the assessment of reservoir quality elements.