Lesson 9: Along Our Coast

Part One

How do you make a saltwater marsh?

Remember how much fun it was to make mud pies? Making a saltwater marsh would be fun, but not quite as easy. If you could create your own saltwater marsh, the recipe would read something like this:

Combine the following ingredients:
      Thousands of gallons of salt water
      Tons of gooey, smelly mud
Add:
      Marsh grass or cordgrass (spartina variety)
      Sea lavender
      Sea lettuce
      Needle rush
Toss in:
      Periwinkles, snails, mussels, shrimp, worms,
      fiddler crabs, fish and insects
Mix:
      All ingredients twice daily to produce tides

Saltwater marshes are one type of wetland you would find near the ocean. Animals and plants in these marshes need salt water to live. Saltwater marshes may have mud flats, open water or shallow grassy areas.

Mangrove swamps are another kind of coastal wetland. They are shallow areas with salt water and many mangrove trees. Mangrove swamps provide homes for wading birds and other wildlife. Shrimp and other sea animals give birth to their young in these swamps. Mangroves are useful in other ways too.

Part Two

What do you think happens to leaves that fall from mangrove trees? They decay and become food for small creatures living in the water. Mangroves growing near the water’s edge also help keep the shoreline from eroding (washing away) during storms.

Mangrove swamps and saltwater marshes are wetlands. They cleanse water before it flows into nearby areas called estuaries.

An estuary is a body of water where salt water and freshwater meet and mix. Freshwater enters the estuary through rivers, creeks and canals. Salt water from the ocean enters through inlets. This mixture of salt water and freshwater is called brackish water.

Mangrove roots in swamp

Part Three

Estuaries are special because both freshwater and saltwater plants and animals depend on them. Florida’s Indian River Lagoon is a very large estuary. It is 156 miles long and contains more species of plants and animals than any other estuary in the United States. Of the 4,300 species found in the Indian River Lagoon, 36 are rare or endangered. This lagoon is the only place in the world where you can find the Atlantic salt marsh snake. It is also home for about one-third of all the manatees in the United States.

Estuaries are important to Florida’s economy. They are spawning grounds and nurseries for commercial fish and shellfish. Estuaries also provide recreational opportunities, such as fishing and boating.

How do these animals depend on each other?

We have already learned about freshwater food chains. Saltwater ecosystems have their own food chains too.

Plants are the first link in a saltwater food chain. They are considered primary producers. Some of these plants are used by a wide variety of organisms. Take sea grass, for example. Manatees love to munch on it!

Part Four

Other animals such as snails and shrimp will ignore the plant itself but nibble on the algae that grows on its blades.

Plant-eating primary consumers such as mullet, shrimp and snails prefer a sort of “salad” called detritus. Detritus is made up of decaying plants that have settled to the bottom. Detritus is also found in freshwater and on land.

Next in the chain are secondary consumers such as snapper or other fish, which dine on shrimp and crabs.

Tertiary consumers (third order) are animals such as ospreys, which swoop down on the water to catch a juicy snapper for dinner. Last in the food chain, tertiary consumers are top predators. They are often the biggest or fastest animals in the food chain. This means they are usually safe from being eaten. But they do die. And when they die, their bodies decay and become nutrients for more plant food.

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