| MadSci Network: Environment/Ecology |
OK, lots of ground to cover on this question, so let's get started:
Pollution can be separated into two main types: man-made and "natural" pollution. Things classified as natural can still be the result of activities of humans, though. Here are some examples of each:
Man-made Natural Pesticides Sewage PCBs Fertilizer PlasticIn general, ocean waters nearest the coast are most polluted (from things coming in from rivers as well as being dumped directly into the water). The most polluted areas will be the ones with the most people living nearby and boating on that water.
Temperature can be a form of pollution. For example, some industries use water to cool things off, which leaves that water hotter than when it was taken from the river, lake, or ocean. The animals in the water may not be able to stand the heat of the replaced water, and it could even kill them. Temperature can also affect other types of pollution, such as fertilizers and sewage. These two types of pollution cause algae to bloom in the water, sometimes even creating what's called a "red tide." Many of these algae live best in warmer water, so temperature plays a role too.
If you need more information, you might check your library for information on the effects of sewage or plastic dumping in the oceans. Plastic is a very large problem, and it is illegal to dump plastic in the ocean anywhere. Red tides are also very interesting, because some of those algae make poisons that are harmful to people who eat clams and mussels.
Good luck in your studies!