Estuary An estuary is a semi-enclosed coastal body of water which has a free connection with the open sea and within which sea water is measurably diluted with fresh water derived from land drainage. (D. W. Pritchard - 1952)
Updated Definition An estuary is a narrow, semi-enclosed coastal body of water which has a free connection with the open sea at least intermittently and within which the salinity of the water is measurably different from the salinity in the open ocean. (Tomczak)
Survival in an Estuary Life in a Transition Zone
As you view the images that follow, observe the environmental conditions for species that live in the estuary. Be prepared to describe physical conditions for one species. Consider conditions such as temperature, space, other species, weather, and water flow.
What is an estuary? An estuary is a partially enclosed body of water where two different bodies of water meet and mix (e.g. fresh water from rivers or streams and salt water from the ocean, or fresh water from rivers or streams and chemically distinct water of a large lake).
Estuaries Estuaries are formed where fresh water meets and mixes with ocean water. Estuaries are found where rivers meet the sea. Estuaries are found where rivers meet chemically distinct lakes.
Each estuary includes a variety of habitats. Some may be bordered by marshes. Estuary features such as swamps or lagoons form behind barrier islands and beaches. Estuary Features and Landforms
Bays, harbors, sounds, and inlets are all estuaries. Estuary Features and Landforms Bayous are formed by channels of slow moving water leading from a river or lake.
Salt marshes form in estuaries in areas protected from highenergy waves. Estuary Features and Landforms Tidal flats are part of many estuaries. Oyster and clams are harvested here.
Estuary Features and Landforms Mangrove forests surround wetland areas in southern estuaries. In mountainous areas, estuaries may be found in seaside fjords.
Estuary Life Many types of plants grow in estuaries. One of the most common is cordgrass. Eelgrass is another common plant that grows in brackish water.
Residents of Estuaries Many bivalves, such as oysters (above), and mussels (below), inhabit estuaries.
Residents of Estuaries Blue crabs are harvested to eat. Diamondback terrapins are the only turtle that lives in brackish water.
Residents of Estuaries Killifish thrive in estuaries. Alewives live in salt water but move through estuaries and into rivers to spawn. They are a favorite prey species for salmon and many other predators.
Residents of Estuaries Coho salmon migrate up rivers to spawn each year, returning to the area they were spawned. Great blue herons feed on fish and amphibians living in estuaries.
Estuarine Research Federation (ERF) St. Marks Florida Estuary - Seagrass Ecosystem Network Analysis page Neuse River Studies Neuse River Bloom Project Neuse River Modelling/Monitoring Team Simulation Model of the Neuse Phytoplankton and Chemistry Pamlico River Studies Water Quality in the Albemarle-Pamlico Drainage 1992-1995 (USGS report) Estuarine Research Reserves NOAA National Estuarine Research Reserve System Ace Basin National Estuarine Research Reserve (South Carolina) Apalachicola National Estuarine Research Reserve (Florida) Chesapeake Bay National Estuarine Research Reserve-MD (Maryland) Chesapeake Bay National Estuarine Research Reserve-VA (Virginia) Delaware National Estuarine Research Reserve (Delaware) Elkhorn Slough National Estuarine Research Reserve (California) Great Bay National Estuarine Research Reserve (New Hampshire) Hudson River National Estuarine Research Reserve (New York) Jacques Cousteau NERR at Mullica River and Great Bay (New Jersey) Jobos Bay National Estuarine Research Reserve (Puerto Rico) Kachemak Bay National Estuarine Research Reserve (Alaska) Narragansett Bay National Estuarine Research Reserve (Rhode Island) North Carolina National Estuarine Research Reserve North Inlet/Winyah Bay National Estuarine Research Reserve (South Carolina) Old Woman Creek National Estuarine Research Reserve (Ohio) Padilla Bay National Estuarine Research Reserve (Washington) Rookery Bay National Estuarine Research Reserve (Florida) Sapelo Island National Estuarine Research Reserve (Georgia) South Slough National Estuarine Research Reserve(Oregon) Tijuana River National Estuarine Research Reserve (California) Waquoit Bay National Estuarine Research Reserve (Massachusetts) Weeks Bay National Estuarine Research Reserve (Alabama) Wells National Estuarine Research Reserve (Maine) Estuarine Advocacy Groups Pamlico Tar River Foundation (PTRF) Chesapeake Bay Foundation