Thermal pollution appears when due to human activity natural bodies of water get to change their normal temperature downwards or upwards. It is very common to use water as a cooling agent for a variety of devices in industry, particularly in power plants, then, this warmer water is returned to the environment but at a higher temperature. Animal species are highly affected by such modifications in their living environment since the levels of oxygen drop while the temperature changes kill fish. Warm water thermal pollution is specific usually for the Northern hemisphere, whereas in the Southern it is the downwards temperature change that causes life damage in the ecosystems.
Another direct impact of thermal pollution on aquatic animals is the acceleration of the metabolism meaning that animals will consume a lot more food than it would be normal. Not only can thermal pollution indirectly lead to food shortage for some species but there will also be modifications in animal behavior, with warmer water species migrating from other areas and ruining the balance of the ecosystems. It has also been noticed that genetic mutations and size increase also occur due to water warming. Consequently, thermal pollution causes damages to food chains and decreases biodiversity in the affected areas.
On the other hand, Australia is one of the countries to have suffered dramatical changes in the river fauna because of the very cold water releases from reservoirs into water courses. This type of thermal pollution has actually led to the disappearance of major fish populations and to the impoverishment of the macro invertebrate species in the rivers. Controlled colonizing of the areas could prove the only solution to such a problem, but it is a sure fact that thermal pollution has to be kept under control one way or the other. Widely using alternative power sources is the first thing to do in order to reduce the reliance on power plants for instance.
Governments should take long term measures to counteract the possible side effects of power plant building and thermal pollution. The population can also contribute to the prevention of thermal pollution by using alternative power sources and saving as much energy as possible. Economic light bulbs instead of incandescent lamps is a first way to reduce the energy consume and lower the pressure power plants constantly put on the environment. It would be totally wrong for us to believe that we are safe from the impact of thermal pollution since everything that ruins the natural balance does affect us one way or the other.