The Effects of Thermal Pollution on Marine Life

Thermal pollution is a unique type of contamination that happens when the discharge from an industrial cooling process degrades nearby water quality by changing the ambient water temperature. Power plants and factories are major contributors to thermal pollution. This type of pollution can have a number of dramatic effects on the local environment.

Thermal Shock

• Thermal shock is a risk of thermal pollution, as many organisms have enzyme systems that are adapted to a very narrow range of temperature, according to Pollution Issues. A sudden temperature change can kill these organisms. Power plants design their cooling water discharges to minimize these effects, but periodic heat treatments that flush out the piping can kill fish. Some power plants have designed a way to increase the heat gradually to drive away fish before the water gets too hot.

Oxygen Depletion

• Even small, chronic changes in the temperature can harm an organism's reproductive system and make them more vulnerable to disease. Cold water has more oxygen than warmer water, and a higher water temperature means organic matter decomposes faster, depleting the dissolved oxygen in the water. The heated water increases the metabolic rates of the organisms, increasing their need for sufficient oxygen.

Forced Migration

• Bad oxygen and temperature environments will prompt organisms to move away from the area and populate new areas, radically changing the ecosystems in both areas. Some power plants have introduced heat-shock proteins to the discharge to protect some organisms from the changes in temperature.

Shorter Plant Life

• An increase in water temperature increases the growth rates of aquatic plants, which results in a shorter life for the plants and overpopulation of the species. A rush of warm water can cause an algae bloom that will reduce the oxygen in the water, cause increased plant respiration, and cloud the water.