Link to Global Warming

And it seems to be tied to global warming. Polovina's study, published in Geophysical Research Letters, finds that the areas of low productivity are expanding in lockstep with increasing water temperatures. As surface temperatures warm, that prevents colder water from rising up from the depths. And that colder water carries the nutrients that would feed the algae.

Scientists studying climate change have predicted this kind of change. But the sea desert has been spreading 10 times faster than climate scientists predicted.So Polovina is a bit cautious — this could be a shorter-term fluctuation, not a permanent change.

"In the next 10 years, maybe it could switch back," he says. "Until we get a much longer time series, we don't know."