Underwater 'Seaview' Allows You Discover Coral Reef

An underwater variant of the Google Street View service will from today begin giving web users an unprecedented photographic tour of Australia's Great Barrier Reef – and another reef in Bermuda will soon be getting similar treatment.

Called the Catlin Seaview Survey, the project is a joint venture between Google, the University of Queensland and their sponsor, a multinational insurance firm called the Catlin Group. Part science project and part public outreach, the aim is to learn as much as possible about the reef's state of health from a panoramic underwater photographic and video survey – and let the rest of us enjoy the reef's untrammelled beauty online.

"For the first time in history, we have the technology available to broadcast the findings of an expedition through Google. Millions of people will be able to experience the life, the science and the magic that exists under the surface of our oceans," says the survey's chief scientist, Ove Hoegh-Guldberg of the University of Queensland in Brisbane.

Triple choice

So far, only a few sample, limited surveys have been undertaken. These are now online and viewable at seaview.org. The project proper kicks off in September, when three surveys begin at 20 points around the 2300-kilometre long reef. Footage from each site will be posted online as the surveys progress.

These comprise a shallow reef survey using a 360-degree camera on a motorised diver-pulling underwater "scooter", a deep reef survey ploughing the depths between 30 and 100 metres using robotic submarines, and a megafauna survey studying the migratory behaviour of tiger sharks, green turtles and manta rays as seawater temperatures increase.

To give deskbound divers a 360-degree view on the web, the camera work is a real challenge, says Richard Vevers, founder of Underwater Earth, the group handling the diving, submarine robots and all camerawork for the survey.

"Issues with water clarity, low light conditions and light distortion underwater called for a very different camera set-up to Street View. The development of the camera has been carried out independently from Google using underwater photography specialists. The result is a very different panoramic camera," says Vevers.

Multiple angles

One camera uses four SLR cameras with extreme fish eye lenses shooting simultaneously to give the full 360-degree image. One of the cameras on the scooter points directly downwards, photographing the surface that the reef is growing from as it travels along.

For those who don't want to steer around a panoramic web page, there are also plans for video capture at each reef location for screening on YouTube – where a bespoke channel is being developed by Google.

"We are also already looking into a 360-degree panoramic video version of the camera, however due to the extremely high volume of data that this involves, further developments are needed in technology before this information could be made accessible online," says Vevers.

Damage checker

The survey data is expected to be useful when the reef is damaged – by ship groundings, cyclones, bleachings and pollution events – and Vevers says the Great Barrier Reef Marine Parks Authority is be interested in visualising such damage with the surveying equipment.

After trying out the virtual dive, Buki Rinkevich, a coral reef expert with Israel's National Institute of Oceanography in Haifa, is impressed. "This virtual dive in the reef is a fascinating experience that may well bring their 3D beauty to the public," he says.

In future, he would like to see the Catlin team give viewers the option of revealing more information about marine life, coral polyps and other reef structures in shot to add to the educational aspect.

Source: New Scientist

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Ocean Present Reduction Made Earth Rotate Rapidly

IT SOMETIMES feels as though some months go by faster than others, but November 2009 really did. Events in the Southern Ocean conspired to make the Earth spin ever-so-slightly faster, shortening half of the days in the month by 0.1 milliseconds each.

Different factors affect how fast the Earth spins. For instance, if the winds that whip around the planet slow down, the Earth spins faster to conserve angular momentum.

There was a more down-to-earth cause in November 2009, however. The Antarctic Circumpolar Current is a powerful ocean current that rings the continent. Stephen Marcus and his colleagues at NASA's Jet Propulsion Laboratory (JPL) in California and at the Institute of Earth Physics of Paris in France noticed that it slowed abruptly on 8 November 2009, only to speed up two weeks later.

Precise day-length data revealed that the changes immediately caused the Earth to spin faster, shortening each day by 0.1 milliseconds. Like the currents, day length returned to normal on 20 November (Geophysical Research Letters, DOI: 10.1029/2011gl050671).

This is the first time we have seen a rapid change in the oceans that is large enough to affect the Earth's rotation, says Marcus. The event is worth noting as the Antarctic currents directly impact the health of the ice sheets.

No one knows for sure why the currents slowed, but Marcus and his colleagues note that it happened in lockstep with atmospheric changes. Two days before the currents slowed, regional winds that move in the same direction slowed too. Two days after the winds went back to normal, so did the currents. Winds help drive currents, so that may not seem surprising. But it's unusual to see such a large response, says Marcus.

Tong Lee, also at JPL, believes that a slightly shifted El Niño may be to blame for the drop in wind speed. That, in turn, could come back to the environmental zeitgeist: models suggest that such shifts will happen more frequently as a result of climate change.

This isn't the only way that climate change may affect Earth's spin. Models suggest that rising sea levels will shift water towards the poles, drawing mass in closer to the Earth's axis and making it spin faster.

Source: New Scientist

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Rain Dissolves Power Beyond Of World's Wind

Every time it rains, a little bit of energy gets wasted. For the first time we have an estimate of the amount of energy falling raindrops pull from the air.

The team behind the calculations say that the atmosphere's energy balance will drop as climate change increases rainfall, slightly weakening winds around the world.

As a raindrop falls it is slowed by contact with the air. This friction takes energy away from the droplet, dissipating it in the atmosphere. The energy – originally from the sun – is not destroyed, but is converted into diffuse heat that cannot be used to generate winds.

This is basic physics, but that doesn't tell us how much energy is lost, says Olivier Pauluis of New York University. With Juliana Dias of the NOAA Earth System Research Laboratory in Boulder, Colorado, he set about finding out.

We know roughly how much energy is dissipated by a single raindrop, so Pauluis just needed an estimate of total global rainfall. He got that from the TRMM (Tropical Rainfall Measuring Mission) satellite, which also told him how far each raindrop fell – a crucial point, as drops that fall further dissipate more energy. On average, 1.8 watts were dissipated for every square metre of atmosphere.

That's a lot, says Dargan Frierson of the University of Washington in Seattle. "Falling water droplets and ice crystals make up only a tiny fraction of the total mass of the atmosphere," he says, but nevertheless they take out a lot of energy. Pauluis's estimate may even be too low, as TRMM is thought to underestimate rainfall.
Small changes in future

As Earth's climate warms due to greenhouse gases, rainfall is expected to increase. The raindrops will also fall further, because in a warmer atmosphere water vapour has to rise higher before it condenses.

Pauluis expects energy losses from rainfall to increase by a few per cent for every degree of warming – meaning there will be marginally less energy available for wind.

That's in line with existing predictions, says Frierson. "We do expect large-scale tropical circulations like the Hadley Circulation and the Walker Circulation to decrease in strength with global warming," he says. The Hadley Circulation helps to power the trade winds and jet streams, which control how weather systems move around the world, a weaker Hadley Circulation would mean weather systems move around slightly less.

The change is unlikely to affect our daily lives, however. The energy loss probably won't affect hurricanes, which are expected to become more powerful as the world warms. That's because the strength of hurricanes is determined by sea surface temperatures, not energy in the atmosphere.

Source: New Scientist

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Resume Building Nuclear Plants in the U.S.

For the first time since 1978, the United States has approved the construction of nuclear reactors. While the decision could herald a new dawn for nuclear power there, the major growth in the sector is likely to be elsewhere.

The nuclear industry had been expecting a renaissance in the next few years, until a major setback occurred – last year's Fukushima Daiichi disaster in Japan. In the aftermath, Japan closed most of its reactors for safety tests, Germany announced it was abandoning nuclear and other countries elected to review their plans.

The situation may now be changing. On 9 February the US Nuclear Regulatory Commission issued a licence for Southern Company, an energy utility based in Atlanta, Georgia, to build a pair of reactors at its Vogtle site. No new reactors have been built in the US since before the Three Mile Island accident in Pennsylvania in 1979.

The Georgia plant will probably soon be followed by a second pair of reactors which the South Carolina Electric and Gas Company wants to build at its VC Summer Nuclear Station in Jenkinsville, subject to licences being granted. The Florida Power & Light Company also hopes to build two new reactors.
Passive safety system

The Fukushima plant overheated when last year's tsunami flooded the engines that powered its cooling pumps. By contrast the Georgia site, along with the other two US sites awaiting approval, will use new AP1000 reactors, built by Westinghouse. These are fitted with passive safety systems that need no power – for instance, a rooftop water tank that can keep the reactor cool for 72 hours.

The US decision suggests the nuclear renaissance may be back on track, though at a slower pace than first expected, according to Tim Abram of the University of Manchester, UK.

He says the real nuclear revival will be in emerging economies, not the US or Europe. "They will build numbers of plants that will dwarf anything we'll ever see in the UK."

China was the first country to commission AP1000 reactors, ordering two pairs. India is also forging ahead, with six reactors under construction to a different design from the AP1000, and more planned.

Abram suspects Japan will also end up building new reactors, despite the government's announcement last year that it would not. The country has almost no energy resources of its own, and has been forced to increase its imports of oil and gas massively over the last few months while its nuclear reactors remain idle. "They are living hand-to-mouth," Abram says.

Source: New Scientist

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