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Marine Pollution: Ocean Acidification

| By Audrey Evangeline Lee
Topics: Cetacean Habitat, Dolphins, Science, Whales

Audrey Evangeline Lee is a writer living in Singapore.


What is Ocean Acidification?

One of the major effects of ocean pollution is ocean acidification. Ocean acidification is the rapid reduction of the pH levels in the Earth's oceans over a period of time, with seriouos consequences for the marine food chain.

Ocean acidification is caused by the ocean absorbing large amounts of carbon dioxide – almost 30 percent - in the atmosphere produced by the burning of fossil fuels and deforestation.  Carbon dioxide is slightly acidic.  As the amount of carbon dioxide increases in the ocean, the pH level of the ocean decreases.

Oceans require a certain level of pH to maintain the natural biochemistry essential for a healthy ecosystem to remain unbroken for the different species living in the water.

Negative Impacts on Marine Animals

In many rich areas of the ocean, the seawater is filled with calcium carbonate minerals essential for many marine organisms.

However, when ocean acidification occurs, corals and bivalves are negatively affected. As the acidic levels in the ocean rise, levels of carbonate decreases.

Diatoms and shrimp-like krill are at the base of the ocean food chain – very small, they survive in calcium carbonate shells in large numbers, providing food for other organisms, including small fish.  Ocean acidification makes it harder and harder for these organisms to form protective shells.

Bivalves such as mussels, oysters, clams, and scallops require calcium carbonate to build their shells. The lower level of carbonate reduces the ability of these bivalves to produce and maintain their shells. It may also cause existing shells to weaken and dissolve, making them more vulnerable and increases their chances of being eaten.

Because bivalves, krill and diatoms are at the bottom of the food chain, once their numbers start decreasing, it will affect the entire food chain.  

Corals will also be affected as they build their own homes from calcium carbonate to form complex reefs and also provide habitat for many marine organisms.  Combined with higher water temperatures, many coral reefs are dying around the world.

Ocean acidification may limit coral growth as the existing coral skeletons will be corroded and it will also slow the growth of new skeletons. This weakens the corals hence they will be more vulnerable to erosion.

Not only will ocean acidification affect corals and bivalves, but fishes will also suffer. Fishes and other forms of sea life will be contaminated, thus they are unable to be consumed by other animals in the sea, and humans as well. The continuing rise of acidic levels in the ocean may also cause reproductive disorders in fishes.

Whales and dolphins, of course, are directly impacted from ocean acidification harming the food chain, as they depend on krill and other small organisms and fish.

Negative Impacts on Humans

Human societies, which depends on goods and services provided by the ecosystems, will also suffer the consequences of the changes in marine ecosystems.

Many economies worldwide depend heavily on fishes and shellfish as a primary source of protein. If the number of these marine organisms continue to decline, society could face significant revenue declines, leading to a loss of jobs and livelihoods as well as coastal food shortages.

Ways You Can Help

Eat less meat. Acres of forests are being cut down to make space for agriculture and farming. Livestock is responsible for producing more greenhouse gasses that all the forms of transport. To feed the livestock, large amounts of fertilizers, fuel, and pesticides are used. Animal waste also contributes to the increase in greenhouse gases as they release nitrogen and methane that pollutes the air.

Reduce the use of energy at home by making sure your home is well insulated, especially around the windows. Turn off lights and unplug power sources when not in use and use shorter cycles on your washing machine.

Lastly, you can also contribute to helping the economy by reducing the use of plastic. Instead of using or buying bottled water, bring your own reusable containers or water canteens.  Support local efforts to ban single-use plastics in your town or city.

Let us all do our part in helping the economy and the marine ecosystems by starting out with these simple steps.


Please consider a donation to the International Marine Mammal Project's efforts to protect whales and dolphins!