1. Life in a Transition Zone
Life in an Estuary
Life in a Transition Zone

2. What is an Estuary?
Where land, rivers, the ocean and the atmosphere intersect
Brackish water(salt and fresh)
80% - 95% of commercial seafood species spend some part of its life cycle here
There are 2 million acres of estuaries in North Carolina
Estuaries are where salt water from the ocean and fresh water from rivers and the atmosphere (i.e. rainwater) meet. This creates what is know as brackish water, which can range in salinity from 35 parts per thousand (ocean water) to 0 part per thousand (fresh water).
Estuaries are very important to NC. Not only does it serve as a nursery for commercial seafood, it also serves as a buffer against storms and hurricanes.
There are approximately 2 million acres of estuaries along in NC. 2

3. 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.

4. 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.

5. 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.

6. 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.

7. Estuary Features and Landforms
Mangrove forests surround wetland areas in southern estuaries.
In mountainous areas, estuaries may be found in seaside fjords.

8. 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.
Plants are not usually termed “residents”

9. Residents of Estuaries
Many bivalves, such as oysters (above), and mussels (below), inhabit estuaries.
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10. Residents of Estuaries
Blue crabs are harvested to eat.
Diamondback terrapins are the only turtle that lives in brackish water.

11. 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.

12. 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.

13. Importance of Estuaries
Sheltered waters provide a “nursery” for sea life to grow. Many species are born in an estuary.
Estuaries protect water quality by filtering dirty polluted river water before it enters the ocean
Estuaries provide protection from flooding during hurricanes and other storms.