Background information
Thermal pollution is the rise or fall in the temperature of a natural body of water cause by human influence. It is caused by a large input of heated water, usually from a single plant or number of plants using the same lake or slow moving stream. Power plants are the leading cause of thermal pollution due to the fact that water is used to keep them from overheating. Environmental engineers and chemical engineers jobs' are to find ways to remove the heat from waste streams so that discharge regulations are satisfied. Unfortunately, the most common way that engineers do this is by taking air or cool water from the environment to exchange the heat with their waste streams. Almost half of all the water withdrawn in the United States each year is used for cooling electric power plants. The cheapest and easiest method to keep these plants cool is to draw from a nearby body of surface water, pass it thorugh the plant and then return the heated water to the same body of water. When water that has been used as a coolant is returned to the natural environment at a high temperature, the change in temperature impacts organisms by decreasing their oxygen supply and effecting ecosystem composition. Thermal pollution can also be caused by urban runoff storm water from roads and parking lots that runs into natural bodies of water.
Thermal pollution can also be caused by the release of very cold water from the base of reservoirs into warmer rivers. This issue has become increasing, due to the increasing call of globalization everywhere. The increase in industries around the world has caused the production of massive amounts of heat energy which in turn, has contributed greatly to the pollution. All the causes of thermal pollution are listed below...
- Power plants creating electricity from fossil fuel
- Water as a cooling agent in industrial facilities
- Doforestation of the shoreline
- Soil erosion
- Agriculture sources
Thermal pollution can also be caused by the release of very cold water from the base of reservoirs into warmer rivers. This issue has become increasing, due to the increasing call of globalization everywhere. The increase in industries around the world has caused the production of massive amounts of heat energy which in turn, has contributed greatly to the pollution. All the causes of thermal pollution are listed below...
- Power plants creating electricity from fossil fuel
- Water as a cooling agent in industrial facilities
- Doforestation of the shoreline
- Soil erosion
- Agriculture sources
effects on aquatic life
Warmer water temepatures lower dissolved oxygen content by decreasing the solutbility of oxygen. When there is less oxygen in water, it causes aquatic oganisms to increase their respiration rates and consume oxygen faster. If you've ever owned a goldfish and left it under a hot light, you may have noticed that the goldfish starts to open its mouth more often because it is respirating faster. Increased respiration may not seem very severe, but it actually is. When have to breath faster it increases their susceptibility to disease, parasites, and toxic chemicals. When heated water is discharged into shallow water near the shore of a lake it distrupts spawning and kills young fish. If the water is too hot, fish and other animals adapted to a certain temperature may die from thermal shock when exposed to different temperatures. Thermal shock is the effect of sharp changes in water temperature when new power plants open up or when plants shut down for repair.
A change in oxygen levels from warmer water also has an effect on algae. Less oxygen means a decrease in the rate of decomposition of organic matter. Green algae start to be replaced by blue algae and many animals fail to multiply. Trout eggs fail to hatch while salmon cannot spawn at higher temepratures. Cold water affects particularly fish eggs and larvae.
Thermal pollution may also change aquatic animals' metabolisms. It increases their metabolic rate, as enzyme activity, resulting in these organisms consuming more food in a shorter amount of time than if their environment had not been altered. An increase in food consumption by a large number of organisms can result food shortages followed by a decrease in population. Changes in the environment also causes fish to migrate from their current location to another, more suitable environment and causes in-migration of fishes that normally live in warmer waters elsewhere. This leads to competition for fewer resources between the organisms that were already there and the ones that just moved in. The more adapted organisms moving in may have an advantage over organisms that are not used to their warmer temperature. As a result, it compromises the food chains of the old and new environments and biodiversity can be decreased as a result.
A change in oxygen levels from warmer water also has an effect on algae. Less oxygen means a decrease in the rate of decomposition of organic matter. Green algae start to be replaced by blue algae and many animals fail to multiply. Trout eggs fail to hatch while salmon cannot spawn at higher temepratures. Cold water affects particularly fish eggs and larvae.
Thermal pollution may also change aquatic animals' metabolisms. It increases their metabolic rate, as enzyme activity, resulting in these organisms consuming more food in a shorter amount of time than if their environment had not been altered. An increase in food consumption by a large number of organisms can result food shortages followed by a decrease in population. Changes in the environment also causes fish to migrate from their current location to another, more suitable environment and causes in-migration of fishes that normally live in warmer waters elsewhere. This leads to competition for fewer resources between the organisms that were already there and the ones that just moved in. The more adapted organisms moving in may have an advantage over organisms that are not used to their warmer temperature. As a result, it compromises the food chains of the old and new environments and biodiversity can be decreased as a result.
Higher temperatures can also cause changes in the cells of organisms. A difference of just 1 or 2 degrees Celcius can cause significant changes in organism metabolism and cells. Changes include rendering cell walls less permeable to necessary osmosis, coagulation of cell proteins, and alteration of enzyme metabolism. These cellular level effects can adverselyt affect the lifespan and reproduction rate of aquatic animals. Warmer water temperatures also increase the growth rate of plants, which resulsts in shortened lifespans and species overpopulation. This causes algae to bloom which reduces the oxygen levels in water. The higher plant density leads to an increased plant respiration rate because the reduced light intensity decreases photosynthesis. Increase temperature also leads to the denaturing of life-supporting enzymes by breaking down hydrogen and disulphide bonds within the quaternary structure of the enzymes. Decreased enzyme activity in aquatic organisms can cause problems such as the inability to break down lipids, which leads to malnutrition.