Foraminifera from paralic zones are protozoa whose use in environmental studies has grown significantly in recent decades, due to their sensitivity to the physical-chemical variations of environments, hence their applicability in mangrove research. In addition, they are widely used in reconstructions of the ancient and recent environment. Coastal areas are among the most productive ecosystems on the planet, presenting a natural dynamic, often characterized by various factors, such as physico-chemical variations, which guarantee the balance and sustainability of these environments. This book includes an environmental assessment of estuarine systems and mangrove areas, both defined as important transitional ecosystems.