Ever Wonder Why The Arctic Ocean Isn’t Full of Freshwater Anymore?

It’s the only instance of a freshwater ocean on the planet.

Transcript

00:00It's easy to tell where glaciers have been on land because they leave glacial valleys and

00:07strange rock formations behind. But on the ocean, that's different. Well, according to new research

00:11published in the journal Nature, the Arctic Ocean was once a vast sheet of ice half a mile thick,

00:16and its water had a distinct peculiarity. Researchers say that the ocean was quite

00:21shallow back then, and it was separated by land from the other oceans. That's because during the

00:25ice ages, so much of the world's water was tied up in glaciers. But when summer temperatures

00:29rose, parts of the ice caps and rivers would melt, meaning the world's smallest ocean was also

00:34completely full of fresh water for a minimum of two glacial periods over the last 150,000 years.

00:41Dr. Walter Giebert of the Alfred Wegener Institute and the studies lead author said about the findings,

00:45To our knowledge, this is the first time that a complete freshening of the Arctic Ocean and the

00:49Nordic Seas has been considered, happening not just once but twice. To discover this, researchers took

00:54sediment core samples from the Arctic Ocean, the Fram Strait, and the Nordic Seas, finding that

00:59thorium-230 was missing from the samples in the same intervals. Thorium-230 being created when

01:04naturally occurring uranium decays in salty water, meaning at those times, the Arctic Ocean

01:09was a giant, albeit shallow, body of fresh water under a massive sheet of ice.