The Ocean Is Getting More Acidic—What That Actually Means

An autonomous glider floats about two miles off Atlantic City, after being deployed by a team from Rutgers University. Researchers are using the glider to sample ocean pH to help them understand how increasing carbon dioxide in the atmosphere is boosting levels of ocean acidity in the water. Photograph by Eric Niiler

Grace Saba steadies herself on the back of a gently rocking boat as she and her crew slide a six-foot long yellow torpedo into the sea. A cheer erupts as the device surfaces, turns on its electronic signal, and begins a three-week journey along the New Jersey coast.

“It’s taken seven years to get this done,” said Saba, who has been working on this experiment since 2011. “I’m so happy, I think I might cry!”

Saba is an assistant professor of marine ecology at Rutgers University, where she is studying how fish, clams, and other creatures are reacting to rising levels of ocean acidity. Acidification is a byproduct of climate change; a slow but exorable real-life experiment in which industrial emissions of carbon dioxide into the atmosphere are absorbed and then undergo chemical reactions in the sea. Rising ocean acidity has already bleached Florida’s coral reefs and killed valuable oysters in the Pacific Northwest.

Now scientists like Saba want to know what might happen to animals that live in the Northeast, a region home to commercially important fishes, wild stocks of quahogs (clams), scallops, and surf clams that can’t swim away from growing acidic waters.

“They are just stuck there,” Saba said.

Saba’s torpedo-like instrument is actually an underwater drone, known as a Slocum glider, that is carrying an ocean acidity sensor. This is the first time that oceanographers have married the two technologies—glider and pH sensor—to get a big-picture view of changes underway in the commercially important fishing grounds of the Northeastern United States.

The glider will travel 130 miles from Atlantic City to the edge of the underwater continental shelf and back. It will complete a series of dives to the ocean bottom, sampling water temperature, salinity, and pH as it swims. The glider will feed Saba and colleagues data on changing water chemistry more quickly than the testing conducted every four years by seagoing oceanographic vessels. 06-15-18

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