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Jellyfish can grow to be pretty large, but they're nothing compared to the size of the ocean. So it may come as some surprise to hear that jellyfish and similar animals could be influencing oceans and the climate on a global scale. That's what a report in this week's issue of the journal Nature suggests. NPR's Geoff Brumfiel has more.
GEOFF BRUMFIEL: It's not obvious that jellyfish would be involved in something as important as climate change. They're not particularly exciting animals. They don't have fins or teeth or even eyes to speak of. And they bob around in pretty much the same way that their ancestors did half a billion years ago.
Professor JOHN DABIRI (Bioengineer, Caltech University): If you see them in the ocean, you think of them as sort of the leftovers in the gene pool, if you will.
BRUMFIEL: That's John Dabiri. He's a bioengineer at Caltech who has been studying jellyfish for the better part of a decade.
Prof. DABIRI: However, jellyfish are actually the first animals to use muscle power to swim. They've survived some major extinction events. And so we actually see them as a model system for successful propulsion now.
BRUMFIEL: In fact, they're more successful than Dabiri, who, as it turns out, is a lousy swimmer. But he's got the upper hand when it comes to fluid mechanics. He's devoted a lot of time to learning about the swirls and eddies that jellyfish make as they swim. For decades, some scientists have speculated that swimming animals might contribute to stirring up water in the oceans, and that's where climate change comes in.
Carbon dioxide from the air dissolves in the surface layer of the ocean. Stirring up the ocean sends that dissolved carbon dioxide to the bottom and stores it there. To find out whether jellyfish were helping the process, his team filmed dozens of the animals. It wasn't easy.
Prof. DABIRI: We actually had a jellyfish that we were measuring out in Woods Hole. It's a place where we go quite often. And you have to understand that it can take a half an hour, an hour to get an animal in the perfect position to take these measurements. And right when the animal was set up, a crab comes out and grabs it in its claw and pulls it away. So we lost our data.
BRUMFIEL: After studying the tapes, Dabiri and his team noticed something. As jellyfish swim, they stir up the water, but they also pull it along behind them. And, Dabiri says, it could work on a large scale. That's because every night, jellyfish and other smaller creatures swim thousands of feet up to the surface to feed. They may be dragging up cold water without much carbon dioxide in it, and pulling down warm water filled with carbon dioxide when they return to the depths.
So could jellyfish help to combat climate change?
Dr. BILL DEWAR (Oceanographer, Florida State University): I wouldn't go so far as to say that jellyfish are a solution to global warming.
BRUMFIEL: Bill Dewar, an oceanographer at Florida State University.
Dr. DEWAR: What I think we can say defensively at the moment is, is that it's a plausible idea, plausible input to mixing, which has been overlooked.
BRUMFIEL: Dabiri says this work means that swimming marine life may need to be accounted for in future computer models of climate change. To do that, scientists need to know more about how the animals behave.
Prof. DABIRI: So it really is a big question mark as to exactly where the animals are at any given time, and which animals are generating the mixing. We need more data.
BRUMFIEL: For John Dabiri's colleagues, that's good news and bad. They're going to be traveling to more great ocean dive spots. But they're also probably going to be getting a lot more jellyfish stings.
Geoff Brumfiel, NPR News.
INSKEEP: And when you're checking the latest news throughout the day at npr.org, you can also find a video, and see jellyfish dragging the water behind them.
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