Marine Pollutants: Thermal Pollution

The Global Water Crisis

Thermal Pollution
Thermal Pollution, image by

Thermal Pollution

Thermal pollution occurs when a body of water’s temperature is changed because of human activities.  In nature, even a slight change in temperature can have dramatic changes on the ecosystem; it can cause some life to die off and others to proliferate until they take over.

Where Does Thermal Pollution Come From?

Nuclear power plants and other industries use water as a coolant.  In other words, large quantities of water are essentially utilized as a heat sink.  Therefore, after being used, the water is usually discharged back into the body of water from which it came (This may be the ocean, a lake or a river).  As a result, when the water gets back into the system, it is often still heated and raises the ambient temperature of the body of water, or the area where it is being dumped.

What Effect Does Thermal Pollution Have on the Earth?

If you have ever owned a fish tank, you have probably been warned about thermal shock. When you are transferring fish from one tank to another, you have to allow water to normalize to the same temperature. As a result, if you suddenly move a fish to a new tank, the slight change in water temperature might be enough to shock the fish’s system, cause it to develop a disease and even kill it.

Unfortunately, this process is what happens in thermal pollution. For example, warmer water affects spawning cycles and can kill young fish. Also, temperature changes may alter the dissolved oxygen levels, causing death in many organisms whose enzyme systems are set to function at a certain temperature. Finally, yet another major change that takes place in warmer water is an increase in decomposition, leading to an abundance of organic nutrients in the water. This causes an increase in algae (and subsequently massive algae blooms), depleting even more oxygen from the water and suffocating other life.

What Effect Does Thermal Pollution Have on Humans?

Because of the increase in bacteria and algae, thermal pollution renders bodies of freshwater unsuitable for human consumption. For example, eating seafood contaminated with algae can cause illness.

Also, thermal pollution can damage commercial and recreational fishing/shrimping industries by decreasing the amount of marine life in the contaminated area.

Ultimately, the financial cost of clean-up and rehabilitation of the affected area is damaging to local economies.  As a result, time and effort has to be expended to create laws and regulations about thermal pollution and to monitor companies to make sure that these laws and regulations are followed.