Water Pollution & Its Effects on Marine Life

People can work to reduce the pollution levels in marine environments.

Water pollution comes in different forms, but all have devastating effects on marine life. Four of these forms are nutrients, toxins, oil and acid rain. They all involve foreign substances going into the water and affecting the chemical and toxicity levels. This in turn affects marine life and their future generations. Even if they will be able to survive and reproduce, the chances of deformity are high, completely changing the process of evolution in the waters where they live.

Nutrients

Once algae takes over, the oxygen the fish need to breathe is consumed.

Nutrients cause an increase in algae, which depletes water of oxygen. This eutrophication causes the suffocation of fish and other aquatic organisms. This is, according to the Global Development Research Center, caused by runoff -- approximately 50 percent from sewage and 50 percent from forestry, farming and other land uses. This sort of algae feeds in coastal waters, creating red tides that ultimately kill the fish.

Toxins

Agricultural drainage is very toxic to our waterways.

Industrial and waste water discharges cause metal toxins to seep into lakes and rivers. Pesticides from farms, forests and homes also create seepage. According to Dr. Peter Moyle of the University of California, Davis, the Kesterson Reservoir, used for agricultural drainage since the 1960s, in California was a prime example of this. From 1982 to 1985, the water was tested by the U.S. Fish and Wildlife Service. The metal levels were more than 500 times what they should have been due to the runoff. As a result, thousands of fish and waterbirds died, and the ones that survived had reproductive issues including developmental abnormalities.

Oil

Oil kills marine life and coastal habitats.

When oil spills, it not only affects the marine life below the water but also the marine birds that fly above it. This is because most oil floats on the surface. According to the Australian Maritime Safety Authority, some fish are attracted to the oil because it looks like floating food, and birds that fly above the water pick the oil up on their feathers. In both cases, this causes death for most as it poisons them, creates a sinking effect and, for birds, leads to hypothermia. The Exxon Valdez oil spill caused the death of 36,466 birds otters and crippled the fishing industry.

Acid Rain

Rain affects us differently than it does marine life, especially when the rain is acidic.

Acid rain is the release of nitrogen and sulfur into the atmosphere from oil and coal combustion that comes from power plants and automobiles. When it hits water, it changes the pH level making that water more acidic and therefore contaminated. According to Moyle, sensitive species of fish and other organisms lose their ability to reproduce and survive.

References

• MarineBio; Essays in Wildlife Conservation, Chapter 11: Wildlife and pollution; Dr. Peter Moyle
• The Global Development Research Center: Sources and Effects of Marine Pollution
• Pollution Issues: Sewage, Animal Waste, and Fertilizers
• Australian Maritime Safety Authority: The Effects of Oil on Wildlife

Resources

• Unwater: Statistics: Graphs and Maps