What is an estuary best defined as?

An estuary is best defined as a coastal area where tidal saltwater meets freshwater. This definition encompasses the unique characteristics of estuaries, where the mixing of saltwater from the ocean and freshwater from rivers creates a rich and productive ecosystem. Estuaries serve as crucial habitats for many species of fish and wildlife, providing both breeding grounds and nurseries, while also acting as natural filters that improve water quality by trapping pollutants and sediment.

The significance of this mixing zone lies in its biodiversity, as estuaries typically support a wide variety of organisms, including aquatic plants, fish, birds, and invertebrates, all of which thrive in the dynamic environments created by the interchange of salt and freshwater. This ecological complexity is essential for the health of marine and coastal environments and underscores the critical role that estuaries play in broader ecosystems.