What’s going on?
The ocean absorbs the extra carbon dioxide we emit into the atmosphere when we burn fossil fuels, and that changes the chemistry of the ocean. We call this “ocean acidification.”
When the carbon dioxide interacts with the seawater, a series of chemical reactions occurs that result in an increase in hydrogen ions. This decreases the pH of the water, meaning it is more acidic.
This change in chemistry also reduces the amount of carbonate ions in the ocean.
Why it matters.
Just as humans need calcium to build their bones, sea creatures need calcium carbonate to build strong skeletons and shells. The decrease in carbonate ions makes it difficult for animals like oysters, corals and sea urchins to build their calcium carbonate skeletons and shells. This effect is known as “osteoporosis of the sea,” because the changing chemistry is causing sea creatures’ skeletons and shells to become thinner or more brittle.
Even if they can build their shells, they must expend more energy to do so, which takes that energy away from other important processes, like reproduction.
Ocean acidification also impacts organisms that do not have carbonate shells. The changing ocean chemistry can impair certain fish species’ ability to detect predators. Increased larval mortality of fish and shellfish has also been observed as an effect of decreased ocean pH.
What you can do.
The solutions to ocean acidification are also the solutions to climate change. Because the decreased pH of the ocean is caused by increased atmospheric carbon dioxide, the best solution would be to decrease fossil fuel emissions.
As an individual, you can reduce your personal carbon dioxide emissions and encourage others to join you. Additionally, if you live near the coast, you can limit nutrient pollution in your yard and community, as that exacerbates the impacts of ocean acidification.
Information from NOAA, Woods Hole Oceanographic Institution, the Smithsonian Institution, the National Network for Ocean and Climate Change Interpretation, and the EPA.