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Estuaries: About


What Is an Estuary?

An estuary is a partially enclosed, coastal water body where freshwater from rivers and streams mixes with salt water from the ocean. Estuaries, and their surrounding lands, are places of transition from land to sea. Although influenced by the tides, they are protected from the full force of ocean waves, winds, and storms to land forms such as barrier islands or penisulas.

Estuarine environments are among the most productive on earth, creating more organic matter each year than comparably-sized areas of forest, grassland, or agricultural land. The sheltered waters of estuaries also support unique communities of plants and animals, specially adapted for life at the margin of the sea.

Many different habitat types are found in and around estuaries, including shallow open waters, freshwater and saltwater marches, swamps, sandy beaches, mud and sand flats, rocky shores, oyster reefs, mangrove forests, river deltas, tidal pools, and seagrass beds. Continue reading from EPA

Where are Estuaries Found?

Estuaries and their surrounding wetlands are bodies of water usually found where rivers meet the sea. Estuaries are home to unique plant and animal communities that have adapted to brackish water--a mixture of fresh water draining from the land and salty seawater.

However, there are also several types of entirely freshwater ecosystems that have many similar characteristics to the traditional brackish estuaries. For example, along the Great Lakes, river water with very different chemical and physical characteristics mixes with lake water in coastal wetlands that are affected by tides and storms just like estuaries along the ocean coasts. These freshwater estuaries also provide many of the ecosystem services and functions that brackish estuaries do....  Continue reading from National Ocean Service

Importance to the Ecosystem

Estuaries are important natural places. In addition to essential habitats for birds, fish, insects, and other wildlife, estuaries provide goods and services that are economically and ecologically indispensable, such as commercial fishing and recreational opportunities.

Estuaries provide critical habitat for species that are valued commercially, recreationally, and culturally. Birds, fish, amphibians, insects, and others wildlife depend on estuaries to live, feed, nest, and reproduce. Some organisms, like oysters, make estuaries their permanent home; others, like horsehoe crabs, use them to complete only part of their life cycle. Estuaries provide stopovers for migratory bird species such as mallard and canvasback ducks. Many fish, including American shad, Atlantic menhaden and striped bass, spend most of their lives in the ocean, but return to the brackish waters of estuaries to spawn. Continue reading from National Ocean Service


Learn More About Marine Ecosystems: From the Collection

Link to Deep blue home : an intimate ecology of our wild ocean by Julia Whitty in the catalog
Link to The Ocean of Life by Callum Roberts in the catalog
Link to Waters of the world : the story of the scientists who unraveled the mysteries of our oceans, atmosphere, and ice sheets and made the planet whole by Sarah Dry in the catalog
Link to The sea trilogy : Under the sea-wind ; The sea around us ; The edge of the sea by Rachel Carson in the catalog
link to the gulf the making of an american sea by jack e davis in the catalog
Link to Ocean : the definitive visual guide by the American Museum of Natural History in the catalog
Link to Ocean anatomy : the curious parts & pieces of the world under the sea by Julia Rothman in the catalog
Link to Systems Biology of Marine Ecosystems by Anjanette S. Tadena in Freading
America's marine sanctuaries: a photographic exploration by US National Marine Sanctuary Foundation in the catalog
Link to The brilliant abyss : exploring the majestic hidden life of the deep ocean and the looming threat that imperils it by Helen Scales in the catalog
Link to Vanishing sands : losing beaches to mining by Orrin H. Pilkey in the catalog
Link to The Atlas of Disappearing Places: Our Coasts and Oceans in the Climate Crisis by Christina Conklin in the catalog
Link to Below the Edge of Darkness by Edith Widder PhD in the catalog

Link to Marine Ecosystems Resource Guide Series Homepage