What Is an Estuary?
An estuary is a partially enclosed coastal body of water where freshwater from rivers and streams mixes with saltwater from the ocean. This creates a unique environment with brackish water—a mixture of fresh and salt water—that supports a diverse range of plant and animal life.
Section 2: Key Characteristics
The primary characteristics of an estuary are its variable salinity and tidal influence. The salinity (salt content) changes with the tides, the season, and the amount of freshwater flowing from rivers. Tides create a constant mixing of water, which circulates nutrients and removes waste, making estuaries highly productive ecosystems.
Section 3: A Practical Example
A classic example of an estuary is the Chesapeake Bay on the East Coast of the United States. Freshwater flows into the bay from over 150 rivers and streams, mixing with the saltwater from the Atlantic Ocean. This creates a vast, rich habitat for crabs, oysters, and numerous species of fish and birds.
Section 4: Why Estuaries Are Important
Estuaries are vital for several reasons. They act as natural filters, trapping pollutants and sediment from river runoff before it reaches the ocean. They also serve as critical nurseries for many species of fish and shellfish, provide flood protection for coastal communities, and support economic activities like fishing and tourism.