The freshwater biome consists of freshwater lakes, ponds, streams, springs, and rivers. These are found all over the world. Many are beautifully landscaped, but some are just downright ugly! Most all bodies of freshwater are enclosed by land, but some rivers and streams empty into the oceans at places called estuaries. Lakes and ponds are divided into three zones. The littoral zone is near the shore where plants and animals are abundant. The next zone is the limnetic zone, which is the open water next to shore, where plankton dominate the water. The last zone is the deep part of the lake/pond called the profundal zone. This is where organisms called heterotrophs, which eat dead organisms that float down from the surface. Temperatures vary in summer from 22*C – 4*C and in winter from 4*C – 0*C. In the spring and fall, the top and bottom layers mix and then the average temperature is 4*C. Streams and rivers are bodies of moving water flowing in one direction. They can be found anywhere, but their exact origin is not really known. They may start out as lakes, ponds, springs, or even melted snow. The characteristics change from the source to the mouth. The source is cooler than the mouth. The water is clearer than of lakes and ponds, and has higher oxygen levels. Freshwater animals such as trout, snails, crabs, and clams along with heterotrophs roam the waters. In the middle part of the stream/river, the width increases, it is less shaded, and more organisms including green plants and algae are found here. Towards the mouth, the water becomes murky and light can penetrate only so far. Fish that don’t loss as much oxygen as other fish, such as catfish and carp, live here. The freshwater biome is home to many beautiful and interesting fauna and flora.