text: In the U.S. Pacific Northwest, oysters bring in $111 million per year. In Australia, where Scanes is a marine biologist at the University of Sydney, it's $26 million. But those millions — and the oysters that bring them in — are in danger. In the Pacific Northwest, baby oysters have died off by the billions. Their tiny shells dissolved before they were fully formed. In Australia, Scanes finds there are more female and fewer male Sydney rock oysters — which could affect how many oysters fill the plates of future Australian diners.
  The cause is ocean acidification. Through their industrial activities and the burning of fossil fuels, people have been pumping more and more greenhouse gases, such as carbon dioxide, or CO2, into the air. The ocean will absorb about one-fourth of that gas. There, it will react with water in ways that make the ocean slightly more acidic. People might never notice the change when going for a swim, but to organisms that call the sea home, acidification is a source of stress. It puts many of the seafoods we love to eat — such as oysters — at risk. And the only way to stop it is to stop the release of CO2 into the air.