There is a great concern about the impacts of climate changes namely due to salinity seawater and temperature alterations in aquatic organisms with the estuarine and coastal environments being the major affected areas. The intensive usage of chemicals in an indiscriminate way in agriculture practices, achieving, in some cases, values above the limits of contamination authorized by the European legislation, also drastically affects the surrounded estuarine areas with profound consequences to the water quality and the aquatic communities. It is known that stressors affect organisms’ physiological conditions with recent works concerning alterations in the fatty acid (FA) profiles associated with environmental and contamination events that become more frequent. FA plays a key role in immune and physiological functions and is associated with the prevention of some diseases, shown to be good bio‐indicators to assess the organisms’ impacts under stress conditions. Thus, this chapter proposes to address natural (salinity and temperature) and chemical (herbicide and metal) stressors’ impacts in the FA profiles of Thalassiosiraweissflogii and Cerastodermaedule and infers about the effects on organisms’ physiological processes and along the food web. Consequences in food resources and to healthier and nutritious food consumption with benefits to human beings are also assessed.
Part of the book: Fatty Acids
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.
Part of the book: Plankton Communities