Ocean Alkalinity Enhancement (OAE) is a method that aims to reduce the effects of ocean acidification and help marine life. It's been suggested that OAE could potentially help marine creatures that make shells or skeletons out of calcium carbonate, known as marine calcifiers. However, recent studies show that OAE might not be as effective as hoped.

The study looked at 27 different types of marine calcifiers. These creatures have been struggling because of ocean acidification, which makes it harder for them to build their shells and skeletons. The study found that some of these creatures, like gastropods and pteropods, have seen a significant decline in their ability to calcify since pre-industrial times. Others, like threshold responders, have seen only a small decline.

Adding alkalinity to the ocean can help these creatures, but the amount needed to fully restore their calcification rates is quite large. For example, adding 50 μmol kg

-1

 of alkalinity can only partially restore calcification rates, with the largest benefits seen in species that are most sensitive to ocean acidification. To fully restore pre-industrial calcification rates, the study suggests that much larger amounts of alkalinity would be needed, especially when considering the equilibration with atmospheric CO

2

.

Moreover, the study found that while OAE can help marine life, it might not align perfectly with climate goals. This is because the process that makes OAE more effective at removing CO

2

 from the atmosphere can also reduce its ability to mitigate ocean acidification. This makes it tricky to use OAE in ocean management and climate policy.

In summary, while OAE has potential benefits for marine life, it's not a straightforward solution. The amount of alkalinity needed to fully restore marine calcification rates is substantial, and the method's effectiveness in mitigating ocean acidification might not align perfectly with climate goals. Therefore, it's important to approach OAE with a critical eye and consider its limitations.

Can Ocean Alkalinity Enhancement Really Save Marine Life?

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