Water currents are common in aquatic ecosystems. In rivers and streams , fast currents occur during the rainy season. In ponds , lakes and seas, water currents are due mainly to differences in Temperature between the upper and lower parts of a water body.
Water currents increase aeration and the turbidity of water. They also carry warm waters to colder regions. These effects of currents affects the distribution of aquatic organisms
The type of organisms that are found in an aquatic habitat is affected by the speed of the water flow. For example , animals living in the fast moving waters usually have structures for attaching themselves to rocks or the substratum, so that they cannot be swept away.
