Hold the Champagne: Climate Change Is Killing Off Oysters
Add oysters to the list of your favorite foods threatened by climate change.
Dramatic failures of oyster populations began in 2006, when aquaculture operators saw die-offs of larvae rocket to 80 percent in the United States. At the time, the reason for these collapses was a mystery, but the science now indicates that rising carbon dioxide levels in the ocean from climate change is causing acidification that interferes with the ability of shellfish to form proper shells and thrive.
But there’s some good news. Thanks to a network of ocean monitors and a new Web portal, West Coast shellfish growers, researchers, and regular people can now find accurate, real-time data on the changing chemistry of nearshore environments with a simple mouse click. Scientists at the National Oceanic and Atmospheric Administration) and researchers at the University of Washington collaborated on the system, which should help growers fight the effects of acidification.
It’s the first time that real-time ocean acidification data has been crunched for public use, making the rapidly changing chemistry of the seas readily apparent and trackable for anyone—from high school science teachers to coastal conservation advocates. The portal—though designed to assist the shellfish aquaculture industry—could demystify ocean acidification killing off coral reefs that serve as habitat for a plethora of marine life.
“Until seven or eight years ago, we didn’t work much on water quality,” said Benoit Eudeline, hatchery manager of research and development at Taylor Shellfish, one of the country’s largest producers. “That may sound strange, but we didn’t need to.”
Climate changed has changed all that. The Pacific Northwest is a fertile shellfish production zone, but it is also prone to the deepwater upwelling that can rapidly shift the acidification levels of a bay or an inlet from day to day.
“The areas can be pretty dynamic,” said Dwight Gledhill, deputy director of NOAA’s ocean acidification program. “Acidification is a pretty long-term process, but in the subsurface, those waters are enriched in CO2, and as you move through time, the expectation is these waters will increase their CO2. Certainly in the past five decades we’ve seen dramatic changes in ocean chemistry.”
Those changes are having dramatic effects on our dinner plates. With the consumption of oysters growing in the United States along with the importance of shellfish aquaculture to regional economies, NOAA scientists responded quickly to the industry’s need for an early alert system for poor growing conditions. With this real-time data, shellfish operators can make micro-adjustments to their systems—adding calcium carbonate to their pools, for instance—or waiting until conditions improve to introduce seed larvae.
“In a hatchery, everything is controlled, man-made, and funneled through pipes,” said Eudeline. “There is a lot that is not fully known about the direct impact of ocean acidification on natural environments—once [the oysters] are out in the bay, there’s not much you can do.”
The outlook for shellfish is rather bleak, says Eudeline. “Even if we reduce emissions right now, things will get worse before it gets better,” he said. “Hopefully we’ll never get to this kind of extreme, but technically you could envision a land-based oyster-growing operation. But the price of oysters would multiply by 10 or 20.”
The new monitoring system, though, is cause for optimism, he said. “The network can serve a multipurpose goal,” said Eudeline. “Shellfish farmers and researchers have a diagnostic tool, and then you have an educational tool for everyday people, who can look at our data to see how things are changing.”
The American infatuation with sweet, briny bivalves may slowly be pushing the awareness of ocean acidification, but NOAA’s Gledhill says we can’t lose sight of the big picture.
“There are other major problems associated with ocean acidification,” he said. “The fact that the southern ocean might become corrosive by the year 2050 is pretty alarming, but there aren’t any industry folks that are really ultimately concerned about that.”