Freshwater regions
Ponds and lakes
Pond and lakes can vary in size, they have a very wide range. They can be very big or very small. Lakes can go on forever. Ponds and lakes are spread out all around the earth and some of them are leftovers from the Pleistocene glaciation. Lakes can last for up to 100 years and possibly longer, whereas ponds are seasonal. They come and go depending on the weather and environment. Pond and Lakes are divided into three zones depending on the depth and distance from the shoreline. The temperature in ponds and lakes vary depending on the environment and the time of the year. During the summer, the temperature can range from 4° C near the bottom to 22° C at the top. During the winter, the temperature at the bottom can be 4° C while the top is 0° C (ice). Streams and rivers These are bodies of flowing water moving in one direction. Streams and rivers can be found everywhere—they get their starts at headwaters, which may be springs, snow melt or even lakes, and then travel all the way to their mouths, usually another water channel or the ocean. The characteristics of a river or stream change during the journey from the source to the mouth. The temperature is cooler at the source than it is at the mouth. The water is also clearer, has higher oxygen levels, and freshwater fish such as trout can be found there. Towards the middle part of the stream/river, the width increases, as does species diversity—numerous aquatic green plants and algae can be found. Toward the mouth of the river/stream, the water becomes murky from all the sediments that it has picked up upstream, decreasing the amount of light that can penetrate through the water. Since there is less light, there is less diversity of flora, and because of the lower oxygen levels, fish that require less oxygen, such as catfish and carp, can be found. Wetlands Wetlands are areas where standing water covers the soil or an area where the ground is very wet. Freshwater wetlands are not connected to the ocean. They can be found along the boundaries of streams, lakes, ponds or even in large shallow holes that fill up with rainwater. Freshwater wetlands may stay wet all year long, or the water may evaporate during the dry season. There are many different types of freshwater wetlands, all of which have different names. This can sometimes lead to confusion. These are all names of different types of wetlands: marsh, bog, fen, swamp, mire, slough, and prairie pothole. These places can look very different, but because they are all areas with wet soil, or where water covers the soil, they are considered wetlands. |
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