科学美国人60秒:Fish Smell Badly in More Acidic Oceans

Rising levels of carbon dioxide are already souring the world's oceans. Globally, seawater has become 26 percent more acidic since the 19th century because of additional CO₂.
 
That's bad news for organisms like coral and plankton that need to form structures made of calcium carbonate and other minerals, because there’s less carbonate in a more acidic ocean.  But it's also bad news for fish.
 
Previous lab experiments had shown that fish living in high-CO₂ waters lost their sense of smell. That deficit caused them to lose their natural avoidance reaction to predators—an obvious challenge for survival.
 
So scientists looked at fish that live on coral reefs near spots where CO₂ naturally bubbles out of the seafloor near Papua New Guinea.
 
The researchers found the same impaired smell—and risky behavior—in the wild fish on reefs near the CO₂ seeps. But the same species of fish in regions with more normal acidity maintain a healthy fear of being eaten. The study is in the journal Nature Climate Change. [Philip L. Munday et al, Behavioural impairment in reef fishes caused by ocean acidification at CO₂ seeps]
 
The research team is now examining whether fish can adapt to more acidic waters. Otherwise, our crazy environmental impacts may make them increasingly reckless.
 
—David Biello