We hear the phrase “ocean acidification” often, frequently connected to conversations around climate change, but what exactly is ocean acidification? The Cooperative Institute for Climate, Ocean and Ecosystem Studies research scientist Sophie Chu walks us through the causes, effects and implications of ocean acidification.

Q: What do you study?

A: My research focuses mainly on evaluating existing ocean carbon sensor technology and developing new technologies to measure the carbon cycle and ocean acidification.

Q: What is ocean acidification, and what causes it?

A: Ocean acidification is the decrease in ocean pH, or increase in ocean acidity, over the last 250 years since the industrial revolution.

Everyone’s heard about global warming; global warming is caused by excess carbon dioxide that humans release into the atmosphere. About 50% of the carbon dioxide we release into the atmosphere stays in the atmosphere, about 20% is taken up by plants through photosynthesis and then the last 30% is absorbed by the ocean. That 30% of carbon dioxide has increased the amount of hydrogen ions that are in the ocean, causing ocean acidification.

Q: Why should we care about ocean acidification?

A: We care about ocean acidification because it affects calcifying organisms (such as oysters and clams) that are really important to the Pacific Northwest fisheries, and the people whose livelihoods depend on them. It will affect all of the marine food web, both calcifying and non-calcifying organisms. There have been some studies that found that fish can’t detect predators as easily in more acidic water. There have also been some studies that have shown that they can’t find their way back home as easily, so there will be effects throughout the food chain.

Q: Who or what is most affected by ocean acidification?

A: Calcifying organisms are most sensitive to ocean acidification. They need something called carbonate to build their skeletons and shells, which is less available when there’s more acidity. If the ocean is more acidic, they need to spend more energy trying to grow a shell instead of on other biological processes, like tissue growth or reproduction.

Q: Is there anything that we, as individuals, can do to help mitigate the effects of ocean acidification?

A: The main thing is to reduce our own carbon footprint. The other side of that is to support efforts around green energy, carbon offsets and carbon removal. It’s kind of depressing to think about ocean acidification, but I want to leave with the hope that everyone can help in their own way to reduce their carbon footprint. Ocean acidification is reversible, we would just need to try really hard to reverse it.