By Christopher Joyce, Source: NPR

The world’s oceans are changing — chemically changing. As people put more carbon dioxide into the atmosphere, the oceans absorb more of it, and that’s making the water more acidic.

The effects are subtle in most places, but scientists say that if this continues, it could be a disaster for marine life.

In fact, some scientists have taken a glimpse of what a more acidic ocean might look like. , a marine biologist at the University of California, Davis, has dived down to vents in the ocean floor where CO2 seeps up into the water column. “It’s like you’re swimming through a glass of champagne where there are bubbles coming up all around you,” she says — but with a shot of vinegar thrown in. And the effects of that acidity are nasty.

It’s really striking,” says Kroeker. “And it’s not, I think, what people want their oceans to look like. The algae tends to overgrow just about everything, so you get a more monotone, green, slimy ecosystem.”

There’s almost nothing alive.

These are natural seeps, not man-made acid baths, and the rest of the world’s oceans aren’t nearly that bad. But even small increases in acidity already are having subtle effects — for example, on shellfish. “It takes more energy for these animals to build their shells in more acidic conditions,” says Kroeker. “These are things like oysters, or mussels or snails.” Anything that uses calcium to build its body — from tiny floating snails called pteropods, to giant coral reefs — suffers when water gets acidic. And, by extension, anything that needs them for food suffers, too.

Kroeker recently reviewed 228 studies of ocean acidification and says there’s a lot of variety in how marine organisms respond to acidity. Some do OK, others don’t. And that’s somewhat hopeful, she says. It has led scientists to find out which plants and animals are the hardiest, and how to protect those that aren’t.

Read the full story at: NPR