1. Where Fresh Water Meets Salt Water
Estuaries
Where Fresh Water Meets Salt Water

2. Estuary Defined
An estuary is a partially enclosed body of water formed where fresh water from rivers and streams flows into a bay or ocean, mixing with the salt water.

3. Estuaries come in all shapes and sizes and go by different names.
Estuaries can also be called bays, lagoons, harbors, inlets, or sounds. Sometimes these water bodies by those names are not necessarily estuaries. The defining feature of an estuary is the mixing of fresh and salt water, not the name!

4. What are some familiar estuaries?
Some familiar estuaries include
San Francisco Bay, Puget Sound,
Boston Harbor, Tampa Bay, and of
course, the Chesapeake Bay.

5. Chesapeake Bay Estuary
The Chesapeake Bay is the largest of about 130 estuaries in the United States.
The Chesapeake Bay is one of the most productive estuaries in America.

6. Chesapeake Bay Characteristics
The bay stretches from Havre De Grace, MD to Norfolk, VA. The bay is about 200 miles long, but along with its tributaries has a shoreline that measures approximately 11,684 miles in total. The Chesapeake Bay is shallow, as its average depth is only 21 feet.

7. Quick Fact: Tidewater is water that is affected by the ebb and flow of tides.

8. Why do Living Organisms need Special Adaptations to Live in an Estuary?
The salinity level (amount of salt in the water) is constantly changing!
If rivers bring in extra water, during periods of flooding, the salinity of the estuary will be reduced.
If drought causes the flow of freshwater to decrease, then the salinity of the estuary may be increased.

9. What type of organisms live an estuary?
The tidal, sheltered waters of estuaries support unique communities of plants and animals, specifically adapted to life where the salinity (amount of salt) constantly changes as freshwater mixes with salt water.
Blue Heron

10. Variety of Estuarine Animals
Shore birds, fish, crabs and lobsters, marine mammals, clams and other shellfish, marine worms, sea birds, and reptiles are just some of the animals that make their homes in and around estuaries.

11. Animals in an Estuary
Copperhead

12. Bay Grasses Add Oxygen to the Water and Habitats for Animals
Cattails
Eel Grass
Common
Waterweed

13. Why are Estuaries Important?
Estuaries are critical for the survival of many species.
They provide ideal spots for migratory birds to rest and refuel during their journeys.
Many fish and shellfish rely on the sheltered waters of estuaries as protective places to spawn. Estuaries are called the “Nurseries of the Seas.”

14. Migratory Birds

15. Estuaries Provide a Variety of Habitats
river deltas
tidal pools
sea grass and kelp beds
wooded swamps
oyster reefs
shallow waters
fresh and salt water marshes
sandy beaches
mud and sand flats
rocky shores

16. Part 2

17. Estuaries are Important for Humans
Cultural benefits include recreation, scientific knowledge, and education.
Boating, fishing, swimming, surfing, and bird watching are just a few of the numerous recreational activities people enjoy.

18. Importance to Humans, continued.
Scientific knowledge and education:
As transition zones, estuaries are invaluable laboratories for scientists and students, providing countless lessons in biology, geology, chemistry, physics, history and culture.

19. Economic benefits include tourism, fisheries, and other commercial activities that thrive on the wealth of natural resources.
The protected coastal waters provide harbors and ports vital for shipping, transportation, and industry.

20. Measuring Economic Benefits
Estuaries provide habitat for 75% of America’s commercial fish catch.
Estuaries provide more than 28 million jobs.
The average American Spends 10 recreational days on the coast of an estuary each year.

21. Health of Estuaries
Unfortunately, an increase in concentration of people near estuaries is upsetting the natural balance of estuarine ecosystems.

22. Part 3

23. People can Harm Estuaries
Channels are dredged, which causes sediment to get in the estuary and cause higher turbidity.

24. People Harm Estuaries…continued
Shorelines are reconstructed to make room for housing and agricultural needs by filling marshes and wetlands.

25. People Harm Estuaries, Continued
Water is polluted and recreation creates excess sediments.
“Over fishing” fish, crabs and shellfish affect the complex food web of the estuary.

26. The Following can Occur in an Unhealthy Estuary:
Fish kills, unsafe drinking water, closing of
beaches and shellfish beds, harmful algal
blooms , unproductive fisheries, loss of
habitat and aquatic vegetation disappears.

27. Windows to the Universe team. Ecosystems
Windows to the Universe team. Ecosystems. Boulder, CO: © University Corporation of Atmospheric Research (UCAR), © , 2000 The Regents of the University of Michigan, December 4, Online. Available: . May 5, 2008.