Some wetlands are wet all of the time, while some aren’t flooded most of the time. Salt marsh wetlands fill with water when the tide comes in, so you can find barnacles, clams and crabs, and fish that feed on plankton and shrimp. (See image of Salt Marsh, from: http://www.learnnc.org/lp/editions/cede_blackwaterriver/53)
Seasonal wetlands are filled in the winter and start to dry out in the summer. When the land is covered with water you will see insects, birds, reptiles, and the plants start to grow. When seasonal wetlands are dry, some animals move deep into the muddy soil and others die off or migrate.
Fresh water marshes have fish, crustaceans (animals with shells, such as crabs), worms, birds, raccoons, mice, insects and other small mammals. Often, even when the wetland dries, there will be small pools of water with larva and small plants. When the wetland surface is dry, the soil will still contains some organisms.
Bogs have acidic water and are known for low-nutrient soil and carnivorous plants. Birds are common, as well as reptiles and amphibians.
Though salt marshes, seasonal wetlands, bogs, and freshwater wetlands are all considered wetlands, they are very diverse. They may be filled with salt water or fresh water, they are dry at different parts of the year, some species will very, and so on. What do you think would happen if you moved an organism from one wetland to another type of wetland?
http://www.epa.gov/OWOW/wetlands/vital/wetlands.html
http://www.geography4kids.com/files/water_wetlands.html
http://www.kidport.com/reflib/Science/Animals/Crustaceans.htm
