Under the Sea

It’s easy to assume that the oceans will just be there the way they’ve always been—full of majesty and mystery; providing sustenance, adventure and escape. But what goes into the air goes into the oceans and the great watery expanse that covers some 71% of the Earth’s surface is beginning to turn corrosive to sea life. The early signs have been unmistakable. Oyster larvae in controlled hatcheries in the Pacific Northwest began to die in large numbers in 2006. It took researchers and hatchery owners years of trial and error to realize that the cause was the ocean water they were pumping in—the water’s pH had fallen, and the early-stage oysters couldn’t form their shells.

Researchers have long known that the oceans act as a giant sponge when it comes to carbon dioxide emissions—they absorb a third of those emissions accumulating from coal plants, cars, factories, planes, trucks and utilities. In all, the oceans swallow some 22 million tons of carbon dioxide a day, and once underwater, the CO2 starts to change the chemistry of the ocean. That chemical change is called ocean acidification and the impacts on shellfish are only the beginning.

As shellfish farmers scramble to better monitor and control the ocean water coming into their tanks, ocean acidification is beginning to impact tiny marine snails known as pteropods—creatures on which a host of commercially important fish (including salmon) depend. And then there are coral reefs—those intricate, magnificent underwater habitats on which more than one million plant and animal species and the lives and livelihoods of countless coastal communities depend. For the world’s reefs, already on the brink thanks to a slew of stressors including pollution, overfishing, runoff and warming waters, ocean acidification is just the latest in a long line of threats. But because it robs the coral of its ability to form a skeleton, it is one stressor for which no easy management or mitigation strategy exists.

So lies the oceans’ dilemma: Emissions are a global problem requiring a global solution, and there is little political will, particularly in the U.S., for taking major action to curb emissions. I wrote this issue’s cover story to provide insight into the main threats posed by ocean acidification, and to lay out some possible solutions, both local and global. In a related Q&A, Duke professor and climate expert Rob Jackson, Ph.D., weighs in on the problem of emissions. Writer Sharon Kelly explores the impacts of shrimp farming, particularly in Thailand, which has led to the wholesale destruction of mangrove forests, important both for hosting coral and for trapping carbon. Calls for sustainable shrimp, a fossil-free future and a global approach to emissions reduction are out there, but in order to prevent the oceans from changing forever, such strategies need to be implemented quickly. And as Jackson points out: “I don’t see a political environment in this country where we’re close to any kind of comprehensive greenhouse gas or carbon bill.”