Carbon-dioxide emissions are boosting acid levels in the waters off the California coast and threatening marine life, according to an article published online today by the journal Science.
Animals including oysters and mussels that depend on calcium carbonate to build skeletons or shells may struggle to survive in 20 years to 30 years because the more acidic the water, the less calcium carbonate it contains, Nicolas Gruber, the lead author of the article and a professor of environmental physics at ETH Zurich, said in a telephone interview.
The potential threat to marine life is another example of how greenhouse-gas emissions are damaging the environment. More than 130 world leaders are expected to discuss climate change in Rio de Janeiro next week during the United Nations Conference on Sustainable Development.
“Oysters in early life stages, the larvae, are sensitive to” an increase in acid levels, Gruber said in an interview.
“Organisms are trying to build shells out of calcium carbonate,” he said. “If the water they live in becomes undersaturated with that, they have great difficulties.”
The issue may affect marine life worldwide and will be especially acute off the California coast, which is naturally more acidic than some other regions, according to the article.
Commercial fishing operations also may be endangered as organisms higher on the oceanic food chain are threatened by acidification’s effects on single-cell algae, coral and surrounding ecosystems, he said.
“There’s a very thin line of not being alarmist but still sounding the bell,” Gruber said. “These changes are coming up very quickly.”