Northeast Greenland ice loss accelerating, researchers say

 Glaciers of Greenland

According to previous measurements and aerial photographs, the northeast Greenland ice sheet margin appeared to be stable for 25 years -- until 2003.

 Around that time, a string of especially warm summers triggered increased melting and calving events, which have continued to the present day.

From Ohio State University

All margins of ice sheet now unstable—and contributing to sea level rise

An international team of scientists has discovered that the last remaining stable portion of the Greenland ice sheet is stable no more.

The finding, which will likely boost estimates of expected global sea level rise in the future, appears in the March 16 issue of the journal Nature Climate Change [DOI:10.1038/NCLIMATE2161].
The new result focuses on ice loss due to a major retreat of an outlet glacier connected to a long “river” of ice—known as an ice stream—that drains ice from the interior of the ice sheet.

 Open water in northeast Greenland, where ice loss is accelerating.

Photo by Finn Bo Madsen, courtesy of The Ohio State University.

The Zachariae ice stream retreated about 20 kilometers (12.4 miles) over the last decade, the researchers concluded.
For comparison, one of the fastest moving glaciers, the Jakobshavn ice stream in southwest Greenland, has retreated 35 kilometers (21.7 miles) over the last 150 years.
Ice streams drain ice basins, the same way the Amazon River drains the very large Amazon water basin. Zachariae is the largest ice stream in a drainage basin that covers 16 percent of the Greenland ice sheet—an area twice as large as the one drained by Jakobshavn.

Composite photograph of a GNET GPS unit implanted in the southeastern Greenland bedrock.

Image by Dana Caccamise, courtesy of Ohio State University.

This paper represents the latest finding from GNET, the GPS network in Greenland that measures ice loss by weighing the ice sheet as it presses down on the bedrock.
“Northeast Greenland is very cold. It used to be considered the last stable part of the Greenland ice sheet,” explained GNET lead investigator Michael Bevis of The Ohio State University. “This study shows that ice loss in the northeast is now accelerating. So, now it seems that all of the margins of the Greenland ice sheet are unstable.”

 This map shows major ice drainages in Greenland, along with measured ice surface velocities.

The northeast Greenland ice stream (NEGIS) now appears to be retreating as rapidly, or perhaps more rapidly, than other parts of the ice sheet, including Jakobshavn Isbræ (JI), Helheim Glacier (HG) and Kangerdlugssuaq (KG).

Catchments for those regions are outlined on the map.

(Image credit: The Ohio State University, Natural History Museum of Denmark)

Historically, Zachariae drained slowly, since it had to fight its way through a bay choked with floating ice debris.
Now that the ice is retreating, the ice barrier in the bay is reduced, allowing the glacier to speed up—and draw down the ice mass from the entire basin.
“This suggests a possible positive feedback mechanism whereby retreat of the outlet glacier, in part due to warming of the air and in part due to glacier dynamics, leads to increased dynamic loss of ice upstream. This suggests that Greenland's contribution to global sea level rise may be even higher in the future,” said Bevis, who is also the Ohio Eminent Scholar in Geodynamics and professor of earth sciences at Ohio State.

Study leader Shfaqat Abbas Khan, a senior researcher at the National Space Institute at the Technical University of Denmark, said that the finding is cause for concern.
“The fact that the mass loss of the Greenland Ice Sheet has generally increased over the last decades is well known,” Khan said, “but the increasing contribution from the northeastern part of the ice sheet is new and very surprising.”

GNET, short for “Greenland GPS Network,” uses the earth’s natural elasticity to measure the mass of the ice sheet. As previous Ohio State studies revealed, ice weighs down bedrock, and when the ice melts away, the bedrock rises measurably in response.
More than 50 GNET stations along Greenland’s coast weigh the ice sheet like a giant bathroom scale.

Khan and his colleagues combined GNET data with ice thickness measurements taken by four different satellites: the Airborne Topographic Mapper (ATM), the Ice, Cloud and Land Elevation Satellite (ICESat), and the Land, Vegetation and Ice Sensor (LVIS) from NASA; and the Environmental Satellite (ENVISAT) from the European Space Agency.

They found that the northeast Greenland ice sheet lost about 10 billion tons of ice per year from April 2003 to April 2012.
According to previous measurements and aerial photographs, the northeast Greenland ice sheet margin appeared to be stable for 25 years—until 2003.
Around that time, a string of especially warm summers triggered increased melting and calving events, which have continued to the present day.
A large calving event at the Zachariae glacier made the news in May 2013, and Khan and his team witnessed and filmed a similar event in July.

 This map shows difference from average wind speed across the Northern Hemisphere for January-February 2014. Blues indicate areas with wind speeds that were higher than the 1981-2010 average; browns indicate winds were lower than average.

In the North Atlantic, an unusually high number of hurricane-force storms have left splashes of dark blue off southeastern Greenland, Norway, Europe, and the western Mediterranean.

(Map credit: NOAA)

Increased ice flow in this region is particularly troubling, Khan said, because the northeast ice stream stretches more than 600 kilometers (about 373 miles) into the center of the ice sheet, where it connects with the heart of Greenland’s ice reservoir.
“This implies that changes at the margin can affect the mass balance deep in the center of the ice sheet. Furthermore, due to the huge size of the northeast Greenland ice stream, it has the potential of significantly changing the total mass balance of the ice sheet in the near future,” he added.
Bevis agreed: “The fact that this ice loss is associated with a major ice stream that channels ice from deep in the interior of the ice sheet does add some additional concern about what might happen.”
The Greenland ice sheet is thought to be one of the largest contributors to global sea level rise over the past 20 years, accounting for 0.5 millimeters of the current total of 3.2 millimeters of sea level rise per year.

Great white shark's epic ocean trek

How OCEARCH tagged and released the first great white in Florida waters, Lydia.

From BBC

A great white shark called Lydia is about to make history as the first of its species to be seen crossing from one side of the Atlantic to the other.

The satellite-tagged 4.4m-long female is currently swimming above the mid-Atlantic ridge - which marks a rough boundary line between east and west.
Lydia was first tagged off Florida as part of the Ocearch scientific project.
The shark has travelled more than 30,500km (19,000 miles) since the tracking device was attached.

Dr Gregory Skomal, senior fisheries biologist with Massachusetts Marine Fisheries, told BBC News: "No white sharks have crossed from west to east or east to west."

Lydia is now roughly 1,600km (1,000 miles) from the coasts of County Cork in Ireland and Cornwall in Britain, and nearly 4,800km (3,000 miles) from Jacksonville, Florida, where she was tagged by scientists in March 2013.

Researchers are using a hydraulic platform to tag the sharks safely - including Lydia (pictured)

Dr Skomal explained: "Although Lydia is closer to Europe than North America, she technically does not cross the Atlantic until she crosses the mid-Atlantic ridge, which she has yet to do.
"She would be the first documented white shark to cross into the eastern Atlantic."
The mere act of tagging a great white shark (Carcharodon carcharias) is a feat in itself.
The scientists have been using a custom-built 34,000kg (75,000lb) capacity hydraulic platform, operated from their research vessel the M/V Ocearch, to safely lift mature sharks so that researchers can tag and study them.

 Lydia is over the underwater mountain system known as the Mid-Atlantic ridge and is now roughly 1,600km (1,000 miles) away from the British Isles
see Ocearch shark tracker

The Ocearch project was initiated to gather data on the movements, biology and health of sharks for conservation purposes as well as for public safety and education.
Though Lydia's journey is impressive, the sharks are known for their marathon migrations of thousands of kilometres.
A great white nicknamed Nicole travelled from South Africa to Australia and back - a circuit of more than 20,000km (12,400 miles) - over a period of nine months between November 2003 and August 2004.
As for where Lydia might go next, Dr Skomal explained: "We have no idea how far she will go, but Europe, the Med, and the coast of Africa are all feasible."

Links :

• BBC : Transatlantic great white shark 'may be pregnant'
• Wired : Spending 15 minutes with a great white shark on a boat deck

Soft robotic fish moves like the real thing

Autonomous, self-contained soft robotic fish at MIT

From MIT news

Soft robots — which don’t just have soft exteriors but are also powered by fluid flowing through flexible channels — have become a sufficiently popular research topic that they now have their own journal, Soft Robotics.
In the first issue of that journal, out this month, MIT researchers report the first self-contained autonomous soft robot capable of rapid body motion: a “fish” that can execute an escape maneuver, convulsing its body to change direction in just a fraction of a second, or almost as quickly as a real fish can.

“We’re excited about soft robots for a variety of reasons,” says Daniela Rus, a professor of computer science and engineering, director of MIT’s Computer Science and Artificial Intelligence Laboratory, and one of the researchers who designed and built the fish.
“As robots penetrate the physical world and start interacting with people more and more, it’s much easier to make robots safe if their bodies are so wonderfully soft that there’s no danger if they whack you.”

Another reason to study soft robots, Rus says, is that “with soft machines, the whole robotic planning problem changes.”
In most robotic motion-planning systems, avoiding collisions with the environment is the highest priority.
That frequently leads to inefficient motion, because the robot has to settle for collision-free trajectories that it can find quickly.

With soft robots, collision poses little danger to either the robot or the environment.
“In some cases, it is actually advantageous for these robots to bump into the environment, because they can use these points of contact as means of getting to the destination faster,” Rus says.

But the new robotic fish was designed to explore yet a third advantage of soft robots: “The fact that the body deforms continuously gives these machines an infinite range of configurations, and this is not achievable with machines that are hinged,” Rus says.
The continuous curvature of the fish’s body when it flexes is what allows it to change direction so quickly.
“A rigid-body robot could not do continuous bending,” she says.

Escape velocity

The robotic fish was built by Andrew Marchese, a graduate student in MIT’s Department of Electrical Engineering and Computer Science and lead author on the new paper, where he’s joined by Rus and postdoc Cagdas D. Onal.
Each side of the fish’s tail is bored through with a long, tightly undulating channel.
Carbon dioxide released from a canister in the fish’s abdomen causes the channel to inflate, bending the tail in the opposite direction.

Each half of the fish tail has just two control parameters: the diameter of the nozzle that releases gas into the channel and the amount of time it’s left open.
In experiments, Marchese found that the angle at which the fish changes direction — which can be as extreme as 100 degrees — is almost entirely determined by the duration of inflation, while its speed is almost entirely determined by the nozzle diameter.
That “decoupling” of the two parameters, he says, is something that biologists had observed in real fish.
“To be honest, that’s not something I designed for,” Marchese says. “I designed for it to look like a fish, but we got the same inherent parameter decoupling that real fish have.”

That points to yet another possible application of soft robotics, Rus says, in biomechanics.
“If you build an artificial creature with a particular bio-inspired behavior, perhaps the solution for the engineered behavior could serve as a hypothesis for understanding whether nature might do it in the same way,” she says.

Marchese built the fish in Rus’ lab, where other researchers are working on printable robotics.
He used the lab’s 3-D printer to build the mold in which he cast the fish’s tail and head from silicone rubber and the polymer ring that protects the electronics in the fish’s guts.

A new flexible robotic fish is the first soft robot

with an onboard power source that can move its body at high speed

The long haul

The fish can perform 20 or 30 escape maneuvers, depending on their velocity and angle, before it exhausts its carbon dioxide canister.
But the comparatively simple maneuver of swimming back and forth across a tank drains the canister quickly.
“The fish was designed to explore performance capabilities, not long-term operation,” Marchese says. “Next steps for future research are taking that system and building something that’s compromised on performance a little bit but increases longevity.”

A new version of the fish that should be able to swim continuously for around 30 minutes will use pumped water instead of carbon dioxide to inflate the channels, but otherwise, it will use the same body design, Marchese says.
Rus envisions that such a robot could infiltrate schools of real fish to gather detailed information about their behavior in the natural habitat.

“All of our algorithms and control theory are pretty much designed with the idea that we’ve got rigid systems with defined joints,” says Barry Trimmer, a biology professor at Tufts University who specializes in biomimetic soft robots.
“That works really, really well as long as the world is pretty predictable. If you’re in a world that is not — which, to be honest, is everywhere outside a factory situation — then you start to lose some of your advantage.”

The premise of soft robotics, Trimmer says, is that “if we learn how to incorporate all these other sorts of materials whose response you can’t predict exactly, if we can learn to engineer that to deal with the uncertainty and still be able to control the machines, then we’re going to have much better machines.”

The MIT researchers’ robot fish “is a great demonstration of that principle,” Trimmer says. “It’s an early stage of saying, ‘We know the actuator isn’t giving us all the control we’d like, but can we actually still exploit it to get the performance we want?’ And they’re able to show that yes, they can.”

Hammerhead shark swarm

It's just a regular dive off the coast of Mozambique -- a dolphin pod here, a few kingfish there -- until a swarm (and we mean dozens!) of hammerhead sharks show up (01:24).
Here's what it's like to find yourself surrounded by hammerheads!
The distinctive-looking sharks are highly threatened by the fin trade, so it's special to see them converge in such large numbers.

Expedition to the end of the world - Official trailer

Expedition to the End of the World - trailer from Haslund Film.

A grand, adventurous journey to the last uncharted areas of the globe.
Yet no matter how far we go, and how hard we try to find the answer, the ultimate meeting is with ourselves and our own transience.

Photographer: Simon Rubardo

Synopsis :
A real adventure film – for the 21st century.
On a three-mast schooner packed with artists, scientists and ambitions worthy of Noah or Columbus, we set off for the end of the world: the rapidly melting massifs of North-East Greenland.
An epic journey where the brave sailors on board encounter polar bear nightmares, Stone Age playgrounds and entirely new species.
But in their encounter with new, unknown parts of the world, the crew of scientist and artists also confronted the existential questions of life.

Teaser Ekspeditionen til Verdens Ende / Teaser Expedition to the End of the World from Haslund Film.

Curiosity, grand pathos and a liberating dose of humour come together in a superbly orchestrated film where one iconic image after the other seduces us far beyond the historical footnote that is humanity.
A film conceived and brought to life on a grand scale  - a long forgotten childhood dream lived out by grown artists and scientists.