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Replicas of the "Little Foot's" bone structures.

Short Science, March 16, 2014

Ocean-going fish can't live any deeper than 8,200 metres, according to a new study. All fish have their limits - you'll never find sharks below four kilometres, for example. But why there are not any fish at all below eight kilometres has always remained a mystery.

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Ocean-going fish can't live any deeper than 8,200 metres, according to a new study. All fish have their limits - you'll never find sharks below four kilometres, for example. But why there are not any fish at all below eight kilometres has always remained a mystery. Now, a team of biologists says the threshold is set by two competing effects of trimethylamine N-oxide (TMAO), a chemical in fish cells that prevents proteins from collapsing under high pressure. While fish should need more and more TMAO to survive ever greater depths, higher concentrations of the compound also draw in more and more seawater through osmosis, the process by which cells regulate their water content. In the deepest waters, high TMAO levels reverse osmosis pressure, swelling brain cells to the point that they stop working and, in principle, bursting red blood cells open. In order to test that claim, the team of scientists explored 7,000 metres down in the Kermadec Trench north of New Zealand. There, they captured five Notoliparis kermadecensis snailfish, whose record TMAO levels and osmosis pressures matched projections the researchers made based on shallower dwelling fish. Washington Post

 

A short, hairy "ape man" who tumbled into a pit in South Africa millions of years ago is back in the running as a candidate ancestor for humans, scientists said. A painstaking 13-year probe has "convincingly shown", they said, the strange-looking creature named Little Foot lived some three million years ago - almost a million years earlier than calculated by rival teams. If so, it would make Little Foot - so named for the diminutive size of the bones - one of the oldest members of the Australopithecus hominid family ever found, said Laurent Bruxelles from France's National Institute for Archaeological Research, who took part in the study. And it would bolster the status of South Africa's Sterkfontein cave complex as part of the "Cradle of Humankind", a UN-recognised World Heritage Site. AFP

 

The Massachusetts Institute of Technology (MIT) has unveiled a robot fish that it claims can change direction almost as fast as the real thing. The fish - or "autonomous soft robot" - can perform escape manoeuvres through rapid convulsions of its body, powered by carbon dioxide released from a canister in its abdomen. Graduate student Andrew Marchese built the fish using 3D printing technology to create a mould, which was used to cast the fish's body from silicone rubber. The project is part of MIT's research into the emerging area of "soft robotics". The Guardian

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