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ambience: ocean
The ocean around Antarctica plays a vital role in maintaining a supply of nutrients to all the world’s oceans. But scientists needed to find a way to trace the currents which distribute the southern ocean’s nutrients worldwide. To find the answer, they turned to the surface layer of the ocean, home of tiny plants known as diatoms. I’m Jim Metzner, and this is the Pulse of the Planet.
“A diatom is a unicellular plant, which is absolutely microscopic.”
Jorge Sarmiento is a professor at Princeton University.
“They produce their cell walls out of opal, essentially out of glass, and these diatoms are incredibly important in the ocean.
“And one of the places where they’re extraordinarily abundant is in the southern ocean, the ocean that rings the Antarctic. And the reason that they are so abundant down there is that they are able to get out of the water the chemical that they need in order to form their glass shells. But the southern ocean has something rather unusual as compared with most other regions of the world, which is that it’s lacking in iron. And the lack of iron in the southern ocean has a very particular impact on diatoms in that they keep building bigger and bigger shells, and when they build bigger and bigger shells, they actually strip the chemical that is used to make the shells out of the sea water. So the water that is actually sinking out of the southern ocean actually has lots of nutrients, but is very low in concentration in this particular chemical that the diatoms make their shells out of. And so we were able to use this unusual characteristic of this water mass in order to trace it around the world.”
Thanks to this new way of tracing ocean waters, scientists have been able to track the currents that move the southern ocean’s nutrients worldwide.
Pulse of the Planet is made possible by the National Science Foundation.
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