Many coastal habitats are found in and around estuaries, including salt marshes, sandy beaches, mud and sand flats, rocky shores, oyster reefs, mangrove forests, tidal pools and seagrass beds. Estuaries are sheltered bodies of water where rivers meet the sea, nutrient-rich freshwater mixes with saltwater, and sunlight penetrates the shallow depths. All of these conditions combine to create some of the most biologically-rich waters on the planet. Species able to adapt to the changing environment and sometimes harsh conditions thrive in estuaries.
Because they are biologically productive, estuaries attract migratory birds as places to feed and stop over during annual migrations. Estuaries also serve as nursery areas where fish and shellfish can grow and mature. Most important species of marine fish harvested as seafood or caught by recreational anglers rely on estuaries at some point in their life histories.
Over half of the U.S. population lives within 100 miles of a coast, including watersheds that empty into estuaries. Increased runoff of pollutants and sediments from urban and agricultural development impacts on water quality in estuaries. Excessive amounts of nitrogen and phosphorous can fuel blooms of algae that deplete waters of life-giving oxygen. Dams and flood control structures also can change the amounts and rates of freshwater flows. Regional cooperation among local governments, states and federal agencies such as the National Park Service is helping to address these challenges.
Move to What You Can Do?
Here are 10 tips from the NOAA that you can do to help protect estuaries.