Transcript What is an Estuary?

Have a seat quickly and quietly
Today we will be learning about
estuaries.
What is an Estuary?
Adapted from http://web.utk.edu/~ctmelear/ossabaw/PattersonStanfordSutton/estuaryL2.html
What is an Estuary?
• Estuary-- a body of water formed where
freshwater from rivers and streams flows into
the ocean, mixing with the saltwater; a place
of transition between land and sea
• Estuary water is known as brackish- a mixture
of salt water and fresh water; salinity is lower
than saltwater but higher than freshwater
What is an Estuary?
• Estuaries are influenced by the tides but are
protected from the force of ocean waves,
winds, and storms by the reefs, barrier islands,
or fingers of land, mud, or sand that define an
estuary's seaward boundary.
• Estuaries come in all shapes and sizes and go
by many different names, often known as
bays, lagoons, harbors, inlets, or sounds.
• Some familiar examples of estuaries include
San Francisco Bay, Puget Sound, Chesapeake
Bay, Boston Harbor, and Tampa Bay.
What is an Estuary?
• The waters of estuaries support unique
communities of plants and animals, specially
adapted for life at the margin of the sea.
• 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.
What is an Estuary?
• Many different habitat types are found in and
around estuaries; along the US coasts, most are
wetlands and are either mangrove forests or salt
marshes
Mangrove Forest
• Have arching prop roots that anchor the trees to
the land
• Roots break up wind and waves protecting
organisms that live there
• Roots also trap sediment so water is rich in
nutrients
What is an Estuary?
Salt Marsh
• Have muddy soil that is rich in nutrients
• Dominant plant is cord grass
• Tide channels running through the grass break
up waves, protecting organisms from the
ocean surf
Why Are Estuaries Important?
They are critical for the survival of many species.
• Birds, fish, crustaceans, mammals, shellfish,
marine worms, and reptiles link to one another
and a variety of plants and microscopic organisms
through complex food web
• Wildlife depends on estuarine habitats as places
to live, feed, and reproduce.
• Estuaries provide ideal spots for migratory birds
to rest and refuel during their journeys.
Why Are Estuaries Important?
• Many species of fish and shellfish rely on the
sheltered waters of estuaries as protected
places to spawn, giving them the nickname
“Nurseries of the Sea.“
• Hundreds of marine organisms, including most
commercially valuable fish species, depend on
estuaries at some point during their
development.
Why are Estuaries Important?
Estuaries work as a natural filtering system
• Water draining from the uplands carries sediments,
nutrients, and other pollutants.
• As the water flows through fresh and salt marshes,
much of the sediments and pollutants are filtered
out.
• This filtration process creates cleaner and clearer
water, which benefits both people and marine life.
Why are Estuaries Important?
Estuaries provide stability.
• Wetland plants and soils also act as a natural
buffer between the land and ocean, absorbing
flood waters and dissipating storm surges.
• This protects upland organisms as well as
valuable real estate from storm and flood
damage.
• Salt marsh grasses and other estuarine plants
also help prevent erosion and stabilize the
shoreline.
Estuaries of North Carolina
• North Carolina’s system of estuaries spans a
surface water area of about 3000 sq miles;
second only to Chesapeake Bay in United
States
• North Carolina estuaries are shallow (<30 ft);
this means sunlight can usually penetrate
through the water, leading to increased
photosynthesis, plant growth, and usable
habitat for a huge variety of organisms
Estuaries of North Carolina
• Great Dismal Swamp- northeast corner of NC,
shared with southeast Virginia
• Pamlico Sound- largest in NC; separated from
Atlantic by the Outer Banks (barrier islands)
• Crystal Coast Salt Marshes- stretch along the
Crystal Coast beaches of NC (Emerald Isle to
Pamlico Sound)
Estuaries of North Carolina