Seals find secrets of deep Antarctic

SCIENTISTS are uncovering the deepest secrets of the freezing Antarctic waters by enlisting elephant seals to carry probes to places never before reached by humans.

The seals’ diving ability is being used to collect data from far beneath the ice shelves of the Antarctic coastlines as well as from the open sea.

The creatures can reach depths of 6,500ft, so revealing information about the ocean’s greatest mysteries. Scientists from the British Antarctic Survey (BAS) and St Andrews University attached miniaturised sensors to about 80 seals, then proceeded to track them.

“The sensors are so good that they can record water temperature, salinity and pressure – even tell us what the animal was doing,” said Iain Staniland, a seal and penguin expert at BAS.

The seals were tagged at the islands of South Georgia, Kerguelen and Macquarie in the Southern Ocean, and at the western coast of the Antarctic Peninsula. Data from the seals were then transmitted back to land via satellite when they surfaced.

“The Southern Ocean is the hardest place in the world to obtain oceanographic data, especially during the winter,” said Mike Meredith, head of the atmosphere and ocean group at BAS. “The seals collected data from deep seas we couldn’t ordinarily access due to remoteness and harsh environments.”

The project’s success has led researchers to tag other marine creatures, such as penguins, fur seals and even albatrosses.

“We are designing very small, light tags to fix to birds so we can gather information on the Antarctic climate,” said Staniland. Such data are vital for understanding the processes that keep Antarctica frozen, and for measuring its responses to phenomena such as climate change. One theory is that the Antarctic stays cold because of a circumpolar current, whose low temperature cools the air above, so effectively insulating the continent.

In recent years, however, some regions, such as the Antarctic Peninsula, have shown signs of warming, and many ice shelves have been breaking up. The data collected by elephant seals could show if warmer currents are disrupting the polar circulation.

The research has also provided intriguing insight to the lives of one of the Antarctic’s most elusive mammals. Elephant seals only come ashore for short periods – once in September-October (to breed), then again in January (to moult). The other nine months are spent entirely at sea – mostly underwater.

Fascinatingly, elephant seals often take catnaps while drifting 1,500ft or more beneath the ice or waves. Scientists believe they have evolved this ability because they have to sleep, yet to do so on the surface puts them at risk of attack by killer whales and sharks. Researchers such as Staniland believe the seals’ most astonishing feature, though, is their ability to recover from a deep dive and head back underwater in just a couple of minutes.

“Diving builds up lactic acid in their muscles and empties their blood of oxgyen, but they reverse that within a few minutes and dive again,” he said. “It is a truly amazing feat.”

However, the diving ability of elephant seals may be rivalled by certain species of whale, in particular Cuvier’s beaked whale. In waters off Italy, this creature was recently found to be capable of reaching a depth of 6,200ft. While this is no deeper than the maximum of the elephant seals, the whale has shown itself able to stay down there for up to 85 minutes.

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Invisibility cloak 'step closer'

For now, the invisibility cloak remains a thing of science fiction Scientists in the US say they are a step closer to developing materials that could render people invisible. Researchers at the University of California in Berkeley have developed a material that can bend light around 3D objects making them "disappear". The materials do not occur naturally but have been created on a nano scale, measured in billionths of a metre. The team says the principles could one day be scaled up to make invisibility cloaks large enough to hide people. Stealth operations The findings, by scientists led by Xiang Zhang, were published in the journals Nature and Science. The light-bending effect relies on reversing refraction, the effect that makes a straw placed in water appear bent. Previous efforts have shown this negative refraction effect using microwaves—a wavelength far longer than humans can see. In order to have the 'Harry Potter' effect, you just need to find the right materials for the visible wavelengths Ortwin Hess The new materials instead work at wavelengths around those used in the telecommunications industry—much nearer to the visible part of the spectrum. Two different teams led by Zhang made objects made of so-called metamaterials—artificial structures with features smaller than the wavelength of light that give the materials their unusual properties. One approach used nanometre-scale stacks of silver and magnesium fluoride in a "fishnet" structure, while another made use of nanowires made of silver. Light is neither absorbed nor reflected by the objects, passing "like water flowing around a rock," according to the researchers. As a result, only the light from behind the objects can be seen. Cloak and shadow The fine structure of the material gives it light-bending abilities "This is a huge step forward, a tremendous achievement," says Professor Ortwin Hess of the Advanced Technology Institute at the University of Surrey. "It's a careful choice of the right materials and the right structuring to get this effect for the first time at these wavelengths." There could be more immediate applications for the devices in telecommunications, Prof Hess says. What's more, they could be used to make better microscopes, allowing images of far smaller objects than conventional microscopes can see. And a genuine cloaking effect isn't far around the corner. "In order to have the 'Harry Potter' effect, you just need to find the right materials for the visible wavelengths," says Prof Hess, "and it's absolutely thrilling to see we're on the right track." Original here

Aussies crack cancer secret

AUSTRALIAN scientists are hoping to cure leukaemia, asthma and rheumatoid arthritis after their breakthrough discovery of how to stop killer blood cells growing.

The team has unlocked the secrets behind the protein which controls the way the blood cancer cells spread when it is damaged - and have found a way to stop its deadly process.

Work is now starting to design a drug to prevent the damaged proteins operating, effectively stopping the cancer as well as asthma and inflammatory diseases such as rheumatoid arthritis.

After spending a decade uncovering the structure of the receptor protein, which sits on the surface of white blood cells, lead researcher Professor Michael Parker, of Melbourne's St Vincent's Institute, said scientists could now build a drug to attach itself to the protein and stop it sending messages into the cells telling them to multiply unchecked.

"If we can stop the signal for the proliferation of uncontrolled growth of the cells then we can stop the leukaemia in its tracks," he said.

Working with molecular biologists at Adelaide's Hanson Institute, the Melbourne scientists used X-ray and synchrotron imaging to build an image of the structure of the protein for the first time, hoping to find a way to block its process.

The GM-CSF hormone - which controls the production of blood cells in the body - works by attaching itself to the receptor proteins, which then send a message into white blood cells telling them to multiply.

When damaged, the protein's messages cause an over-production of cells or cells which persist too long, resulting in diseases such as leukaemia as well as some inflammatory conditions.

The major breakthrough came when the researchers realised the proteins linked together to form networks on the surface of white blood cells after being activated by the hormone, and that by stopping the networks forming they could also stop the growth.

Liam Heudebourck, who was diagnosed with asthma four years ago, was yesterday hopeful about the discovery.

The Camden seven-year-old was admitted to hospital in March after suffering a major attack.

"If scientists found a cure or something that could help not to have his puffer every day, that would be great," his mother, Belinda English said.

While the drug development phase has only just begun, Professor Parker said it would be easier to target a protein on the surface of the cell rather than trying to come up with a molecule to break its way into the centre of the cell.

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