Scientists uncover more evidence of warmer oceans

SAN FRANCISCO BAY, Calif. For some of those answers, researchers are looking at some of the world's smallest creatures found directly off the coast of California.

For a few hundred copepods, the bad luck of the draw is picking the wrong day and the wrong rock along San Francisco Bay because the plastic cup is their destiny.

"They're really common, but really small -- about a millimeter long," said Ph.D. candidate Morgan Kelly with UC Davis.

Kelly has done a lot of dipping in the past two years, beginning in Mexico and traveling as far north as Oregon, and while this was one of the colder days, she's all about learning the effects of global warming.

"We want to understand whether species are able to evolve in response to climate change," Kelly said.

One species of copepod, called Tigreopus californicus, is especially well-suited, according to advisor Dr. Rick Grosberg.

"It's significant because these little creatures are about the toughest we know in the sea," Grosberg said, "and they're telling us they can't take much more than they are taking now."

As sea creatures go, Tigriopus is fairly benign -- not a big part of the food chain. As soon as a female develops eggs, a male makes the scene, and for Tigriopus, life doesn't get much more fulfilling than that.

They were ideal for the experiment because each colony remains pretty much isolated from every other, meaning they have adapted to specific, long-term temperature ranges. Each generation lives only five weeks, meaning that if any species could evolve fast enough to keep pace with climate change, they could.

"I think over time I have counted thousands of dead crustaceans," Kelly said.

Back in the lab, Kelly has spent a few years pushing and measuring their ability to survive in warmer temperatures, and the outcome is not good.

"That means they are already at their limit," Kelly said. "Living close to the upper-temperature limit."

"These creatures might tell us that a little more change is potentially catastrophic," Grosberg said.

That's nothing we haven't heard before, just another creature that's adding to the weight of evidence.

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