— A guide to the big sto­ries in science

Noble gases can mea­sure the av­er­age tem­per­a­ture of the world’s oceans.

Cosmos - - Contents -

It would look nice in a drink, but the air bub­bles in this 24,000 year-old ice core drilled from the Antarc­tic po­lar ice cap of­fer a new way to mea­sure the av­er­age tem­per­a­ture of the oceans.

Mea­sur­ing the av­er­age tem­per­a­tures of the oceans is a di­a­bol­i­cally dif­fi­cult thing to do. While 90% of the planet’s heat is sunk into the oceans, it is un­evenly dis­trib­uted.

Bern­hard Bere­iter, of the Scripps In­sti­tu­tion of Oceanog­ra­phy, and his col­leagues mea­sured the con­cen­tra­tions of noble gases within the air bub­bles trapped within the an­cient ice.

They be­lieved noble gases like ar­gon could pro­vide a pre­cise ther­mome­ter. Cool oceans ab­sorb noble gases while warm­ing oceans re­lease them into the at­mos­phere. Be­cause the noble gases don’t in­ter­act with other mol­e­cules, they just shuf­fle be­tween the at­mos­phere, the ocean and back.

“Our study clearly shows that the ba­sic idea – the con­nec­tion be­tween the con­cen­tra­tion of noble gases in the at­mos­phere and the av­er­age ocean tem­per­a­ture – is cor­rect,” says Bere­iter.

The study, “Mean global ocean tem­per­a­tures dur­ing the last glacial tran­si­tion”, was pub­lished in Na­ture.

CREDIT: BERN­HARD BERE­ITER / SCRIPPS IN­STI­TU­TION OF OCEANOG­RA­PHY / EMPA / UNIVER­SITY OF BERN

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