Science has a prescription for the ocean’s heartburn. Some side effects are worth it

A project to de-acidify bay waters saved baby oysters in Oregon — and has the potential to save the oceans. We just need to get more comfortable with geoeingeering to do it.

Oyster shells in the ocean
primeimages / Getty Images

George Waldbusser is a professor of ocean ecology and biogeochemistry and graduate program director for the Ocean, Earth, and Atmospheric Sciences program at Oregon State University, and a public voices fellow of The Op-Ed Project. 

More than a decade ago, I was called upon to work with oyster hatcheries in Oregon that were seeing unprecedented and catastrophic deaths of their baby oysters. These businesses provide the foundation for much of the industry on the the West Coast and beyond by selling three-week-old oyster “seed” to farmers, who plant them in bays and estuaries and raise them until they reach market size. 

But the seeds weren’t even surviving the incubation period, creating major shortages and threatening growers from California to Washington. Hatchery operators and farmers were desperate to know what was causing the oyster seed crisis, and what could be done to restore production.

Industry leaders, scientist colleagues, and I eventually tied the failures directly to the change in marine chemistry from carbon dioxide emissions, a process called ocean acidification. The additional CO₂ was making it extremely difficult for newly hatched oysters, no bigger than the diameter of a strand of hair, to make their first shells in a bay where hatchery operators had successfully produced oyster seed for several decades.

The “evil twin” of climate change, ocean acidification has increased the average acidity of the ocean by approximately 30 percent since the industrial revolution. I think of it as the heartburn of the sea, and it was threatening thousands of jobs in rural coastal communities. Fortunately, it also presented an opportunity to try something new: We prescribed an antacid.

A rather nondescript oyster hatchery sitting on a small bay in Oregon became one of the first in the world to buffer incoming seawater with sodium bicarbonate, which lowered the acidity and helped resolve most of the production problems. The hatcheries limed their water much like farmers lime their fields to improve soil fertility. Since the intervention in 2010, regional hatchery output has increased by billions of oyster seed annually. This small-scale ocean alkalinity enhancement project has now been used successfully around the world by intrepid aquaculturists and is being evaluated as a potential approach within a larger framework of ocean carbon dioxide removal by the National Academies of Science.

This treatment for oceans falls under the umbrella of geoengineering, the large-scale intervention and manipulation of earth’s systems and processes to alter the earth’s climate in an attempt to mitigate global warming and ocean acidification. Geoengineering is not without controversy. Human intervention is what has damaged planet Earth, so human intervention should cause collective pause and reflection. However, we can no longer prevent the damage from climate change and ocean acidification merely by reducing carbon dioxide emissions. It’s time we get more comfortable with geoengineering, even as we stay alert to the hidden costs and potential for unintended consequences.

By deploying ocean antacids we are essentially speeding up the natural rock weathering processes that would bring them to the oceans slowly through rivers and streams. The quantity of natural material available on land is massive; unfortunately, weathering is hundreds of times slower than our current rates of carbon dioxide increase. 

Fix Solutions Lab, 2 August 2021. Full article.

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