Freshwater Biomes

            Most of the rivers, lakes and ponds located on the continents contain fresh water. Fresh water has a much lower salt concentrations than ocean water. It also has greater temperature and seasonal variations than marine biomes. Because of these variations, organisms living in freshwater biomes must adapt to environmental changes that marine organisms do not experience.

Categories of Freshwater Biomes

Moving Water Biome

            Moving water biomes consist of streams and rivers. The moving water of rivers makes life difficult for organisms living in the water. Because vegetation is frequently swept away by moving water, rivers contain few algae and other small plants. Animals in rivers must therefore feed on insects that fall into the water, and on dead plants and animals that are carried into the water from the land.

            Many animals living in rivers have adaptations that prevent them from being washed away in the current. Insects have large special hooks, tadpoles have suckers and such fish as trout and salmon have streamlined bodies that resist the fast-moving currents.

Standing Water Biome

            This type of freshwater biome includes lakes and ponds. The main difference between ponds and lakes is their size. In general, ponds are smaller and more shallow than lakes. Ponds are usually shallow enough for light to reach the entire bottom. In contrast, light can reach only some parts of a lake bottom.

            Eggs, seeds and small organisms are often carried into ponds by wind and running water. As a result, ponds tend to have a large variety of plant and animal life. Pond animals include a variety of fishes as well as frogs, insects, turtles and birds. Vegetation includes algae, along with rooted and floating plants.

            Shallow lake water contains many of the same kinds of organisms found in ponds. Insect larvae live near the shorelines of lakes, where they pass through their developmental stages rapidly. Freshwater phytoplankton are the main producers in the parts of lake away from the shore, in deeper water. Organisms living in this part of the lake also feed on decaying plant and animal remains that wash into the water from the land.

Protecting the ecosystem does not tell us to avoid any change, but that we should recognize that human-induced changes can have far-reaching and often unpredictable consequences. Ecology is a call for wisdom, care, and restraint as we alter the ecosphere.