A MARTÍNEZ, HOST:
Climate change is forcing animals and plants to move because their habitats are getting hotter and harder to survive in. One of the most consequential shifts involve some of the smallest living things on the planet. Lauren Sommer from NPR's climate desk has more.
LAUREN SOMMER, BYLINE: A paleontologist is a scientist who studies fossils. Adam Woodhouse is a micropaleontologist. So when people hear that, they ask him...
ADAM WOODHOUSE: Oh, is that like tiny dinosaurs?
SOMMER: It's not tiny dinosaurs. As a postdoc at the University of Texas Institute for Geophysics, he studies plankton - a kind called Foraminifera.
WOODHOUSE: They're about the size of a grain of sand. They just float around in the ocean.
SOMMER: And when they die, their tiny shells fall to the ocean floor and become microfossils. Over time, there are layers of them that build up, and the layers tell a story.
WOODHOUSE: So you just kind of have pages of the book of life. The more sediment you dig up, the more kind of pages you're opening as you go down.
SOMMER: In a study in the journal Nature, Woodhouse and his colleagues found that 8 million years ago, when the oceans were warmer, plankton were in different places. They were closer to the poles - about 2,000 miles from where they are now. And that matters because with climate change, we're heating up the oceans again. So the question is...
WOODHOUSE: Are those plankton going to move back to where they were, 2,000 miles away from the equator, again?
SOMMER: Why care if plankton are moving? They're the base of the food chain. So where they are, you'll also find...
WOODHOUSE: Tuna, billfish, krill and squid. And these organisms, of course, provide sustenance and the livelihood to billions of people around the globe.
SOMMER: Scientists are already seeing this plankton shift. Charlie Stock, a research oceanographer at the National Oceanic and Atmospheric Administration, says in the past, plankton had millennia to adjust to changing oceans.
CHARLIE STOCK: The key difference is the pace of that change. You know, with anthropogenic climate change, we're talking about looking at changes that are introduced rapidly over a century time scale.
SOMMER: And when plankton and fish move, entire fisheries could shift from one state or country to another.
STOCK: And that's certainly an issue that's already causing friction internationally and nationally.
SOMMER: It's why climate change is making protecting the ocean even harder. Predicting those changes could help, and that means closely tracking its tiniest planktonic creatures.
Lauren Sommer, NPR News. Transcript provided by NPR, Copyright NPR.
