What is an estuary?

An estuary is defined as the area where a river meets the ocean, creating a unique and dynamic environment. This region is characterized by the mixing of freshwater from the river and saltwater from the ocean, leading to nutrient-rich waters that support a diverse array of wildlife. Estuaries serve as critical habitats for various species, including fish, birds, and invertebrates, which thrive in this productive ecosystem. They also provide essential services such as water filtration, flood protection, and nursery areas for juvenile marine organisms. The ecological importance of estuaries is underscored by their role in both the aquatic food web and coastal protection, making option B the correct and most comprehensive definition of an estuary.