There are so many different kinds of wetlands that scientist cannot name them all. The plants, animals, climate and topography of Rivers and Lakes are unique and found nowhere else in the world.

Topography

Surprisingly, only three percent of the worlds water is fresh. Lakes hold twenty percent of all the worlds fresh water. Lake Baikal in Russia, holds one fifth of the worlds fresh water! Most rivers start high up in the mountains. Some rivers and lakes can be turned to salt water or vice versa. An example of a salty lake is the dead sea, it is nine times saltier then the ocean! The great lakes, the biggest bodies of fresh water in North America were formed by glacial activity. Most Canadian wetlands were formed this way also. Lakes normally last only fifteen thousand years. Some lakes aren’t formed by glacial activity though, some can form in craters or cracks in the earths surface.  The biggest river in the world, the amazon is South America, carries more water then the next ten biggest rivers combined! The Mississippi, being the second largest river in the world, has been damned up, and now cannot flow freely killing some animals. The Mississippi was vital to recolonization after the ice age. When a river meets the ocean, it drops all of its sediment creating huge deposits called deltas.

Climate

Rain is the source of all fresh water.  Cold water means higher oxygen content. Once they slow down they get warmer, supporting more life. Most wetlands are temporary and dry up during the summer or dry season, the amazon is a great example, during the wet season it floods a huge area of forest each year. Although it doesn’t dry up it does grow considerably during the wet season. Wetlands preserve bodies so well that a man was found, dead, with stubble still on his chin! Some lakes are saltier then the ocean. Without the sun we would have no liquid water and therefore no life.

Animals and Plants

Salmon are an amazingly strong species of fish, they travel upstream for thousand’s of miles each year to get to their breading grounds. Giant salamanders live in japan and are about two metres long and live up to eighty years! Otters, at four months old fish in rivers, they aren’t very good fishermen at that age so the parents share their catches. Crocodiles are predators of otters, to drive the crocodiles away, these bold creatures harass it until it leaves. Two million wildebeests cross the Nile river in Africa each year, once again the crocodiles prey upon these creatures. Almost all freshwater fish evolved from one. Eighty percent of the species in Lake Baikal are found nowhere else on earth. Forty percent of the worlds fish species live in fresh water. The Amazon in South America, contains more species then in the entire ocean! All fish must swim from lake to lake to prevent extinction if the lake drys up, as you can see, the fish and species of wetlands don’t live in a very stable environment.

Peat, is created from dead plant material, it eventually gets compressed and changed into coal.

Conclusion

The rivers and lakes of the world have abundant plants and animals, but human activity is endangering the ecosystem. People are polluting, destroying habitats and over hunting.