A new high-resolution computer model of ocean acidity off the coast of California spells disaster for the local marine ecosystem, according to a new study published in Science last Thursday (June 14). Led by ocean biogeochemist Nicolas Gruber of the Swiss Federal Institute of Technology in Zuric, researchers modeled how atmospheric carbon dioxide emissions over the next 4 decades will lead to a rapid rise in ocean acidity in the California Current System—a complex system of currents extending more than 600 miles offshore and stretching from Oregon to Baja California, Mexico.
A rise in acidity will in turn lead to a reduction in carbonate ions in the water, which will lower the saturation rate of a mineral form of calcium known as aragonite. Both carbonate and aragonite are essential components for the shells and skeletons of oysters and other shell-building organisms. If the saturation of aragonite falls below a certain threshold, for example, calcium carbonate shells will dissolve.
The new model predicts that by 2050, the upper water layer of the California Current System—where the bulk of organisms live—will be undersaturated half of the year. Currently, these waters are undersaturated 2 to 4 percent of the time.
"It's dramatic how fast these changes will take place," Richard Feely, a chemical oceanographer at the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle, Washington, told ScienceNOW.
"It shows us that the windows of opportunity for organisms to succeed get smaller and smaller,” added George Waldbusser, an ocean ecologist and biogeochemist at Oregon State University, Corvallis.