What

1
Whats an Estuary?
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What is an estuary?

• An estuary is a body of water formed where
  freshwater from rivers and streams flows into the
  ocean, mixing with the seawater.
• Estuaries and the lands surrounding them are
  places of transition from land to sea, and from
  freshwater to saltwater.

3
Estuaries trap nutrients and sediment that are
carried from the land by rivers and from the
ocean by tides. The tidal action and river flow
are constantly mixing these nutrients creating a
fertile area for plants and animals.
4
Estuaries are influenced by the tides while being
protected from the full force of ocean waves,
winds, and storms. Estuaries are shallow and
sunlight penetrates to the bottom. This promotes
plant growth.
5
Estuaries are one of the most productive
ecosystems on Earth. Estuaries are also good
nurseries because they provide a protected
environment for species to hatch and grow in
before they migrate to the sea.
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Estuaries help control coastal erosion and reduce
inland flooding. Estuaries also serve as
environmental filters as the plants (like salt
marsh grass) and animals (like oysters) filter
pollutants out of the water.
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Estuary Features and Landforms

• 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.

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Estuary Features and Landforms

• Bays, harbors, sounds, and inlets are all
  estuaries.
• Bayous are formed by channels of slow moving
  water leading from a river or lake.

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Estuary Features and Landforms

• Salt marshes form in estuaries in areas protected
  from high-energy waves.
• Tidal flats are part of many estuaries. Oyster
  and clams are harvested here.

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Estuary Features and Landforms

• Mangrove forests surround wetland areas in
  southern, tropical estuaries.
• In mountainous areas, estuaries may be found in
  seaside fjords.

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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.

Brackish water has more salinity than freshwater
but not as much as seawater.
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Residents of Estuaries

• Many bivalves, such as oysters (above), and
  mussels (below), inhabit estuaries.

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Residents of Estuaries

• Blue crabs are harvested to eat.
• Diamondback terrapins are the only turtle that
  lives in brackish water.

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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.

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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.

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