Freshwater ecosystem types

Freshwater ecosystems
There are several different types of freshwater ecosystems.
Freshwater has a low salinity. In this video is cover streams and rivers, along with lakes and ponds.
In addition, I cover wetlands. There are two major types, swamps, and marshes. A marsh is a wetland without trees and a swamp has trees growing in the water.
There is no standard definition about the size of a pond or a lake, however, the water in lakes and ponds have low salinity.

Aquatic Biomes Crossword
http://www.moomoomath.com/aqua....tic-biomes-crossword