Salt Marshes and Estuaries

Two Marine Ecosystems

What is an Estuary?

• Partially closed body of water with a mixture of fresh and salt water.

• Found near river mouths• Places of transition from land to sea and

from fresh to salt water.

What is a Salt Marsh?

• Coastal wetlands on protected shorelines

• Found on the edges of estuaries• Low coastal grassland• Transitional zone between land and

water

Location

• Found along any ocean coast, all over the world.

Abiotic Factors

• Tides• Temperature• Salinity (Salt)• Flow Depth• Marsh Age• Sediment Properties• Ice

Biotic Factors: Algae• Algal mats

• Algae grows into huge greenish gray mats. Some call it dragon-vomit

• Sea lettuce is a high component of the mats. • Form in shallow water in the late summer

• Pannes• shallow ponds in salt marshes created by poor

drainage, uneven distribution of sediment, or ice scouring. Extreme salinity and high temperatures prevent colonization by grasses. Sea Lettuce, Eelgrass, Ditch-grass and filamentous algae can grow there.

Biotic Factors: Plants

• Plants in a salt marsh are halophytic• Can excrete excess salt and/or retain

water• Are food for other species and

provide nutrients when they decompose

• Saltwater Cordgrass – found primarily in the low marsh, is a tough, dense grass that stands close to the water and can handle submersion

Biotic Factors:Plants

• Salt Meadow Grass – forms large meadows farther up on the tide line in the high marsh.

• Rush – mixed with cordgrass or alone forming strands in the mud.

• Glasswort – a salty plant that turns red in the fall.

Biotic Factors:Plants• Sedge – found throughout salt

marshes. Identified by their three-sided stems

• Sea-milkwort: small plant with pink flowers. They form dense beds in the mud.

• Arrow Grass – toxic to humans, grows in different sizes, can be found in the lower marsh.

• Seaside Goldenrod – found in the drier areas of marshes. Produces tall yellow flowers

Salt Marshes:Invertebrates

The ribbed mussel can be up to 10 cm

long. It is most commonly

related to the Blue Mussel.

The Salt Marsh Mud Whelk.

Belongs to the Whelk family,

more commonly

known as “Sea Snail” family, and can grow up two cm. in

length.

Salt Marshes:Invertebrates

The Common Dorcas Copper Butterfly has a wing span of 19 to 27 mm. long.

And is most commonly

related to the Purplish Copper.

Salt Marshes:Invertebrates

The Common Green Crab can

be found globally in a number of different

habitats. In the Salt Marsh they reach 7.5 cm.

Salt Marshes:Invertebrates

The Nine Spine

Stickleback is the smallest

of Sticklebacks, and is a food

source for many of the birds in the Salt Marsh.

Salt Marsh:Vertebrates

Salt Marsh:Vertebrates

The Black Duck typically measures

59 cm. (head to toe). Its ducklings are born able to

tolerate high concentrations of

salt.

The Great Blue Heron is also

know as the Blue Crane. When standing with

legs completely extended the Heron reaches about 1 meter

high.

Salt Marsh:Vertebrates

The Salt Marsh Kingfisher is one of the 90 different types of Kingfisher.

Its typical height is 33

cm.

Salt Marsh:Vertebrates

Raccoons, along with

other marsupials, feed on the

Mud Whelk and Ribbed oysters

found in the Salt Marshes.

Salt Marsh:Vertebrates

Estuaries:Invertebrates

The common periwinkle is actaully

found in a number habitats, but are

incredibly common among the muddy

waters of estuaries. Typically reach 3.1

cm.

The False Angel wing

mussel uses its sharp ray to bury itself

deep into the mud. Typically reaches 5 cm.

Estuaries:Invertebrates

Estuaries:Invertebrates

Lobsters, along with crabs, use

their large claws to break open and eat

the many different

mussels found in the estuary.

Estuaries:Vertebrates

Flounder are the most commonly

found fish in estuaries. They are

able to bury themselves in the

mud when threatened and

become completely camouflaged.

Estuaries:Vertebrates

The Osprey Bird, sometimes called the Fish Hawk, is

known for its ability to fly from great heights and catch fish in the waters below.

Estuaries:Vertebrates

Also found in Salt Marshes, the

American Alligator is a very important

part to both habitats. They are

the largest reptile in North America,

reaching up to 16 ft.

Estuary Food Web

Salt Marsh Food Web

Salt Marsh Keystone Species:American Alligator

Estuary Keystone Species: Mangrove crab

Competition

• The three main species in a salt marsh are Bids, Plants and fish. In between each of these species competition goes on. In the birds competition occurs in order to fight over fish, space and mates

Symbiosis

• Symbiosis is in layman's terms getting a helping hand. There are such things as mutualism (both parties benefit), Communalism (One benefits, other isn't harmed) and Parasitism (where one is helped and the other is harmed)

Crock Huntin’The American Alligator, left,

excavates depressions in its habitat that fill with water.  During dry times, these gator holes may be the only places with water.  Thus, to all the organisms whose survival depends on the water in those holes the alligator is a keystone mutualist.  Of course, the gator might eat a few of those things that come to live in its old home. But hey a gator’s got to eat!

Habitat Threats

• Any trash or sediment in a river naturally ends up in an estuary, since the river current slows due to the widening or running into the tidal force of the ocean. This leads to long term pollution, and the eventual killing off of many habitual animals.

Habitat Threats

A major issue salt marshes and estuaries are facing is industrial and housing development. Wetlands are considered highly valuable for developing, and it is estimated that 215 million acres have been developed world wide thus far.

Habitat Threats

Other problems include chemical deposit (which leads to erosion and sediment), irregular flow (caused by irrigation and damming), and salt water deposits, which can kill fresh water animals.

The Importance of Estuaries

Estuaries are home to a great many different plants and animals that we depend on for food. A number of commercially valuable fish return from the ocean to reproduce in the calm waters of salt marshes and estuaries. Oysters, clams and other shellfish thrive in bays and inlets, as do many species of crabs and fish.

The Importance of Salt Marshes

Salt marshes are particularly important because they are among the most productive habitats on earth and are home to a wealth of plant and wildlife species.