A wetland is a type of ecosystem in which water covers the land either throughout the year or at least, a part of the year. Such wetlands may contain water that either flows or is standing. Water can be freshwater, salty water, or even brackish water. Brackish water is water that is formed as a mixture of fresh and salty water. Wetland acts as the breeding grounds for many fishes, insects, and other marine life.
Estuaries are also a type of wetland. They are formed by meeting of freshwater from river with the salty water from the sea. Such ecosystems are shallow and hence are able to get maximum sunlight. They serve as the spawning places for many marine species. Primary producers produce food and are mostly consumed by the detritivores.
Some example of wetland are swamps, bogs, and marshes whereas, some examples of estuaries include salt marshes and mangrove swamps.