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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: Brittle Shell Keeps Octopuses Afloat
18 May 2010 7:01 pm
In 300 B.C.E., Aristotle proposed that the brittle white shells found on female argonaut octopuses functioned as a kind of boat, allowing the creatures to sail on the water surface. More recently, scientists have suggested that the shell is primarily used to incubate the argonaut's eggs, and also to trap air for buoyancy: Unlike most octopuses, argonauts live near the sea surface rather than the seabed, and they need to control their depth to avoid being crushed by waves or eaten by seabirds. (The diminutive males, which are up to 8 times smaller and 600 times lighter than the females, don't need this buoyancy aid.) To test this idea, scientists captured three female argonauts and scuba dived with them after releasing them into a nearby harbor. In a study published online tomorrow in the Proceedings of the Royal Society B, the researchers report that when they inverted an argonaut underwater to allow the air to bubble out from its shell, the creature became negatively buoyant--i.e. it sank if it didn't swim. However, when the argonaut then swam to the surface, it took air into its shell and reclaimed its control of buoyancy as it dived underwater.
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