Whales swallow half a million calories in single mouthful

Faint disturbances in the heart of Antarctic waters gives way to

breathtaking images of whales hunting krill

in this fantastic video from BBC natural history masterpiece, Planet Earth.

From LiveScience

The filter-feeding strategy of blue whales, the largest animals on Earth, may explain their enormous size, according to a study that determined a single mouthful of food can contain 457,000 calories, or 240 times as much energy as they burn when grabbing that mouthful.

Blue and some other whale species eat by taking enormous mouthfuls of water and filtering out their meals, often tiny crustaceans called krill, using plates of baleen made of keratin, a protein found in hair, fingernails and feathers.
A team of researchers led by Jeremy Goldbogen, who is now at the Scripps Institution of Oceanography, calculated the efficiency of eating this way.

Their math supports the long-standing assumption that baleen whales are much more efficient feeders than their smaller relatives, the toothed whales, which hunt down individual prey.
The finding is detailed today (Dec. 9) in the Journal of Experimental Biology.

Although the finding isn't a surprise, the baleen whales' efficiency is unprecedented in the animal kingdom, said study researcher Robert Shadwick, who studies animal biomechanics at the University of British Columbia.

"When they take a gulp of water, they are filling their mouths with the amount of water equal to their own body mass, so there is nothing that comes close to doing that," Shadwick told LiveScience.

These whales may eat an enormous quantity of food in a single gulp, but the effort is taxing.
As the animals dive, they lunge into a school of krill and their mouths open to 80 degrees and inflate like a parachute as water gushes in.
This creates a drag, slowing the whale. Whales can make up to six lunges in a dive, according to the researchers.

To figure out how much energy the whales use when they dive, researchers recorded 200 dives between 2002 and 2007.
Then a doctoral student, Goldbogen used recordings of the sounds whales made as they dived through the water to calculate their speed.
He recruited a parachute aerodynamics expert to help work out the forces acting on the whales as they lunged.
Ultimately, they calculated that the whales spent as much as 8,071 kilojoules (1,900 Calories) on a single lunge.

The researchers then measured the jaw bones of whales in museums to estimate the volume of the whales' mouths.
They combined this with krill densities to determine how much energy the animals captured in one mouthful. The answer: up to 1,912,680 kilojoules (about 457,000 Calories).

"They are doing something that is energetically very expensive, but they are getting an enormous payoff," Shadwick said.

Links :

• BBCNews : Blue whale's gigantic mouthful measured
  

The Sharm shark mystery: why are the attacks happening?

Frightening: One of the sharks killed by officials who believed it was responsible for the attacks. But after this shark was killed, the attacks started again (Reuters)

From TheTelegraph

As arguably the world's foremost chronicler of shark attacks, George Burgess knows better than anyone what the sea's most ferocious predator is capable of.

His position as curator of the International Shark Attack File, a database started by the US Navy in the 1950s, has forced him to confront the results in mortuaries around the globe.
It is always a harrowing experience, one that demonstrates the fragility of the human body when faced with some of the most powerful jaws in the animal kingdom, as some of the more chilling entries in the shark attack file would attest.

Take the case of Shirley Anne Durdin whose head was decapitated and body torn in two after a White Shark attacked her as she snorkelled for scallops of the South Australian coast in 1985.
Then there was Theo Klein, disembowelled by another White that proceeded to tear chunks of flesh from his dead body in front of hundreds of horrified onlookers in 1971 after he was caught in its jaws off the breakers in Buffalo Bay, South Africa (see Jawshark.com)

Perhaps because the file, which contains over 4,000 investigations of shark attacks dating back as far as the 16th century, is largely secret, Mr Burgess is reluctant to discuss recent individual cases.

But when it becomes to the business of killing, it is clear that some sharks go about their task with all the finesse of a medieval executioner faced with a treasonous Plantagenet courtier.
"If something is big enough to get its mouth around your head, the neck is very easily severed," he said. "It can be done in several bites or maybe in just one. A large, fully-grown white shark could cut a human in half."

As a scientist, who was drawn into his profession by reading the books of the oceanographer Jacques Cousteau as a child, Mr Burgess has little appetite for the gore of shark attacks that exercises so morbid a fascination on the rest of us.

Yet the bearded conservationist admits that the shark attacks that have taken place off the Egyptian Red Sea resort of Sharm el-Sheikh in the past fortnight are "right up there" with the most fascinating investigations he has ever mounted.

Over the space of six days, sharks struck at swimmers in relatively shallow waters along a three-mile stretch of beach lined with some of the most exclusive hotels on the Red Sea Riviera. Four people were maimed and a fifth was killed.

Called in to investigate by panicked Egyptian authorities, Mr Burgess was swiftly able to establish that at least two of the attacks were carried out by the same oceanic whitetip shark, an astonishing revelation in a generally extraordinary case.

In recent years, experts have largely debunked the notion that single "rogue" sharks, unlike the predator dreamt up by the author Peter Benchley in Jaws, ever strike more than one victim. Having discovered that the taste of human flesh is not to their liking, the vast majority of sharks do not make the same mistake again.

Yet photographic evidence clearly showed that a whitetip with a distinctive notch in its tail-fin attacked a Russian man on Nov 30, taking off part of his leg.

Six days later, the same shark returned to a nearby stretch of water by the Hyatt Regency hotel.
As her partner Rudi looked on in horror, Renate Sieffert, a German tourist who had been coming to Sharm el-Sheikh for 10 years, was pulled under the water.
Others swimmers described how she screamed as the churning waves around her turned red while the shark thrashed about, tearing at its victim.
By the time she was pulled ashore, Renate Sieffert was dead.

The whitefin has been all but absolved of involvement in two of the attacks, thought to have been carried out by shortfin makos, but remains a possible suspect in the mauling of Olga Martsinko, a Russian-Ukrainian woman.
So savage was the attack that her left buttock was ripped off, exposing the base of her spinal column.

Only once before has there been unimpeachable evidence of a shark striking more than one human victim.
In 1916, a great white killed four people and injured a fifth along an 80-mile stretch of shoreline off the New Jersey Coast.
The attacks captured the public imagination and became the inspiration for Jaws.

Although Mr Burgess has investigated that case exhaustively, even recreating the attacks around Matawan Creek, where three of the attacks took place on the same day, he has never been able conclusively to prove why the shark behaved in the way it did.

But the most convincing explanation, he says, is that the great white was in some way injured or malformed, forcing it to attack humans because it was unable easily to hunt its normal prey.
The same may be true of the serial attacker off Sharm el-Sheikh.
"It is something we are looking at here," he said.
"Was this just a shark that made a couple of errors of judgment or decided that humans were ok, or was it an act of desperation by a shark trying to make a living in order to survive?"

Solving the mystery is a little like mounting a murder inquiry.
In the days he has been in Egypt, Mr Burgess has been questioning witnesses, studying photographs, forensic evidence and pathologist reports and scouring the waters near each of the incidents.
The most pertinent questions revolve around what the sharks were doing so close to the shore in the first place.
Both whitetips and makos are pelagic sharks whose natural habitat is far out to sea - and it is here where they are most dangerous.

Whitetips were involved in the deadliest attack on humans ever recorded when they attacked survivors pitched into the water after the USS Indianapolis was struck by a Japanese torpedo in the Pacific in the dying days of the Second World War.
Over 800 sailors survived the initial attack, but over the course of four days in which they trod water clung to flotsam and died of thirst and exposure, at least two dozen, possibly many more, were picked off by whitetips.

But until last week's attacks only two juvenile whitetips had been seen off the coast of Sharm el-Sheikh all year, according to Elke Bojanowski, an expert on Red Sea sharks.

Preliminary findings suggest that humans, both directly and indirectly, are at the very least accessories to the crime.
Unusually warm water temperatures for the season, perhaps the result of global warming, may have lured the sharks into the northern reaches of the Red Sea, far from their normal habitats.

A ship carrying sheep from Australia is also a prime suspect, after it tossed carcasses and waste into the sea as it voyaged up the Red Sea.
With such a powerful sense of smell, sharks from 100 miles away could have been attracted by the ship - whose owners are facing possible litigation from the Egyptian government - according to Mr Burgess.
When the meat dried up, the sharks would have struggled to find food because of a dearth of tuna, their favoured prey, probably as a result of overfishing.

Despite everything he has seen, and although he nearly became one of his own statistics after narrowly escaping an encounter with a Lemon Shark by attempting to bop it on the nose, Mr Burgess is a true shark lover.
Sharks may inspire a visceral, even primal fear in humans, particularly after Jaws - a film Mr Burgess says set back the cause of shark conservation by 20 years - but in reality they pose us little danger.

There are an average of five shark-related deaths a year.
By contrast, human beings kill up to 75 million sharks annually, for their fins, a delicacy in China, their meat or simply as bycatch.
With some species seeing their numbers fall by 99 per cent in 50 years, the king of the seas is facing a battle for its survival.
Which is why, he says, it would send the wrong message to hunt and kill the sharks responsible for the Sharm el-Sheikh attacks.
Doing so would not make the beaches safer anyway, something that would be better achieved by increased monitoring of the seas so that beaches can be closed - as happens in America - when sharks are spotted close to shore.
"To catch that animal, you are going to have to find it first," he said.
"That's a lot of expenditure in human time. But in the end what have you got? Sure, you have some retribution for what it did but you have no assurance it was going to do it again and no assurance that its mates won't do it again."

Links :

• TheTime : The Red Sea shark attacks, killing spree puzzles scientists
• TheGuardian : Sharm el Sheick, scientists give initial findings on shark attacks
  

NOAA rescues Civil War-era coastal charts, now available online

Yakutat Bay (1741) oldest nautical chart from historicalcharts.noaa.gov

From GCN

A collection of nearly 400 Civil War era charts once again is available to the public, now in an online searchable database hosted by the National Oceanic and Atmospheric Administration, providing a historical record of U.S. terrain, ports and coasts as they were from 1861 to 1865.

“The agency has an amazing legacy,” NOAA Chief Geographer Meredith Westington said.
“We’re talking about 200 years’ worth of history.”

NOAA, together with the Library of Congress, still is in the process of digitally scanning 28,000 coastal and geodetic survey charts, and plans to launch a new version of the historical Web site in February, with a geographic information system that will enable searches of the collection using map coordinates.

The project is more than simply digitizing existing collections, Westington said. “It was more of a rescue effort” when it began in 1995 at an off-site printing facility used by NOAA. “They were closing their doors and they were going to throw out thousands of things.”

NOAA was notified and began gathering the documents. “We were pulling things from map drawers without knowing in advance what they were. Most of this stuff should have already been in the National Archives anyway.”

The online Civil War collection was launched in October in anticipation of the 2011-2015 sesquicentennial of the war and has received about 6,000 new hits since going up.
It is part of a larger historical collection that contains more than 21,000 maps and charts dating from 1747 to 2001.
It includes 394 maps and nautical charts, as well as documents including Notes on the Coast of the United States, secret records covering the coast from the Delaware Bay to the Mississippi Sound on the Gulf Coast.
The notes include detailed handwritten descriptions of ports and navigable rivers, along with sailing directions with positions of hazards, lights, beacons and buoys.

“The new collection is one of our more popular pages at the moment,” said Westington.
“We’ve received nearly as many questions about our historical maps and charts as our latest-edition nautical charts.”

A word of caution: The historical charts are marked “not for navigational use.
If you plan sailing through Charleston or Baltimore Harbor, use an up-to-date chart.

The process of digitizing historical material for preservation and online access is continuing
The equipment used has varied since 1995, when the metadata was collected by hand.
Much of that collection work now is automated, and for the past five years most of the scanning is being done by contractors, primarily HOV Services in Beltsville, Md., which provides document imaging and management services.

Current requirements call for the scanning to be done on a Crystal XL 42-inch wide format color scanner from Contex A/S of Denmark, in an uncompressed TIFF format at a minimum resolution of 300 dpi, in 24-bit color.
Information collected for each chart includes scan file name, date and resolution; chart title, edition and date; the dimensions of the original paper and the map on it; and the corner latitude and longitude.

The data is recorded using Microsoft Access and transferred to a larger PostgreSQL open-source object relational database.
PostGIS adds support for geographic objects to the database, spatially enabling the PostgreSQL server for geographic information systems.

When the GIS tool is enabled on the NOAA Web site, users will be able to search by coordinates or drill down from a reference map to find the desired documents, rather than using a word search in the collections.

Links :

• NOAA : How the U.S. Coast Survey Helped ‘Chart a More Perfect Union’
  

Age of sail boats inspires green solutions

Wind-powered tall ships are once again important as oil prices hurt trade

From CNN

With its long hull, towering masts and expansive sails, it resembles a schooner from the 19th century.
But fitted with a series of high-tech features, this so-called "sail ship" is designed to cut carbon emissions on the high seas today.

Part of a fleet of carbon-neutral, wind-powered sail ships planned by Britain's B9 Energy, it's just one example of how companies are looking to the past for greener alternatives to the gas-guzzling vessels that transport the world's cargo.

When it comes to wind power replacing fuel in shipping vessels, "it's not a question of if, but when," according to David Surplus, the chairman of B9 Energy, Britain's largest windfarm operator.
"By most people's estimates, we have reached peak oil -- sooner or later the fuel will run out and there will simply be no alternative," said Surplus.

Roughly 87% of international trade is carried out by the shipping industry, figures from the International Maritime Organization show.
With the majority of world trade traveling by sea, the shipping industry is responsible for around 4% of global carbon emissions, according to the latest figures available from the United Nations.

B9 expects its 100% carbon-neutral trading ship to be in production by 2012.
B9 claims its vessel will be the first commercially produced merchant ship to harness alternative energy, but it certainly isn't alone in using old-fashioned sail boats to move goods.
"At the moment it's happening on a fairly small, fairly local scale," said Jan Lundberg, founder of Sail Transport Network, a group that promotes sailing as a means of eco-friendly, cost-efficient trade.

But the trend is growing, he said, pointing to examples like El Lago Coffee Company, which uses traditional sail boats to ship Guatemalan coffee beans to the United States, and the Sail Transport Company, a Seattle-based group that uses sailboats to deliver "petroleum-free organic produce."

B9's new eco-friendly ships, planned to be in production by 2012, signify a return to a much more traditional form of merchant shipping.
Before diesel-powered steel tankers came to dominate the seas, international trade was conducted on vast, wooden sail ships.

The 100% carbon-neutral freighter will feature automated, self-adjusting sails that respond to minute changes in the wind to maximize propulsion.
The boat will also take advantage of "skysail" technology -- a kite-styled towing system currently used on some cargo ships to improve fuel efficiency.
In addition, a biofuel-powered engine will operate under less windy conditions.

Surplus says that with these technologies, the B9 sail ship will be able to carry up to 9,000 tons of cargo. That's just a fraction of the more than 100,000 tons that much larger ships used for long-haul trade can carry, he admitted.

But B9 will initially just operate within Europe, particularly in the North Sea and Baltic where the winds are strong.
Surplus added: "There are currently about 1,500 similarly sized fossil fuel-powered ships working along these routes and our dream is to replace all of them."

Whether sail ships can replace modern freighters on a large scale, however, remains to be seen. Jeremy Harrison, communications director at the British-based Chamber of Shipping, has his doubts.
"I would love to see sail boats replace the current system," he said. "But I just can't see how it will be economical, even as fuel prices rise."
According to Harrison, advances in fuel efficiency onboard super-large cargo ships will help offset the rising cost of fossil fuels.
"Big shipping companies have already made huge savings just by 'slow steaming' -- reducing their speeds to save on fuel consumption," he said.

Earlier this year Maersk, the world's largest container shipping firm with more than 600 ships, announced that it had adapted its giant marine diesel engines to travel at super-slow speeds -- reducing emissions by 30% and saving a reported $100 million in the process.

"Unless you can build a sail-powered boat as big as the ships that are out there today, it will be very difficult to achieve the economies of scale to make it competitive," Harrison said.
Surplus, however, is undeterred.
He said: "A lot of people don't understand what renewable energy has achieved onshore. If you simply transfer those economic models across to shipping, it completely transforms the economic proposition."

Links :

• SkySails : shipping vessels with towing kite system (YouTube)
• CTMV, maritime sail transport company
• E-Ship 1, a rotor or Flettner ship
• Cousteau Turbosail
  
• Physicsworld / BBC : cloud-seeding ships could combat climate change
• Windships, modular sailing rigs for larger vessels
• ShippingEfficiency, vessel energy efficiency rating & container CO2 rating for the world's shipping fleet
  

Seeing through bubbles: new method uses dolphin-inspired sonar

Watch the dolphins at SeaWorld Orlandos Dolphin Cove as they artfully create and play with underwater bubble rings and hear what SeaWorlds trainers, educators and guests have to say about this fun and fascinating behavior.

From TechNewsDaily

By thinking about how dolphins might solve problems using echolocation — the method the marine mammals use to locate objects within water — researchers have come up with a way to detect objects through bubble clouds that would effectively blind man-made sonar systems.

The new technique could prove helpful in shallow waters, where bubbly water is more common and where sonar is increasingly finding use.

Sonar operates much the same way as the echolocation used by dolphins and bats.
By analyzing the differences between emitted sound pulses and their echoes, sonar can detect and identify targets.

Unfortunately, standard sonar does not perform well when bubble clouds are present, which scatter sound and clutter sonar images. Bubble clouds are common from breaking waves in shallow waters.

"Cold War sonar was developed mainly for use in deep water where bubbles are not much of a problem, but many of today's applications involve shallow waters," said researcher Timothy Leighton, a physicist at the University of Southampton.
"Better detection and classification of targets in bubbly waters are key goals of shallow-water sonar."

"Look at the coastal waters around the Persian Gulf -- they are full of crud-like bubbles from breaking waves on the shoreline and mud from the rivers Euphrates and Tigris," Leighton told TechNewsDaily. "Mines here are hidden.
The U.S. Navy used dolphins and divers here, as sonar did not work to find mines in this region."

Leighton turned to dolphins for inspiration after learning that the animals weave circular “bubble nets” around schools of fish.
The nets force the fish to cluster together, making them easier for the dolphins to pick off.

“It occurred to me that either dolphins were blinding their sonar when making such nets, or else they have a better sonar system,” Leighton said.

Scientists don’t know what type of sonar dolphins use while hunting with bubble nets, so Leighton couldn’t copy from dolphins directly.
"I sat down and worked out what pulse I would use if I were a dolphin," he said.

The result was a new sonar concept named twin inverted pulse sonar (TWIPS).
This novel technique exploits the way that bubbles pulsate in sound fields, which influences the characteristics of sonar echoes.

This method uses a series of twinned pairs of sound pulses, with the first pulse of each pair emitted a fraction of a second before its twin.
The waveform of the first pulse is an inverted replica of that of its twin.

Unlike the case with inert solids, sound pulses cause bubble walls to move significantly.
The bubble expansion that a sound pulse causes cannot exactly match the bubble compression experienced by an inverted replica of that pulse -- although the bubble can expand as far as it likes, it cannot compress to the point that it disappears altogether.
In this way, researchers can tell which echoes reflected off solid targets versus those from bubbles.

In experiments in a water tank, the researchers found their method outperformed standard sonar at detecting a small steel disc under bubbly conditions resembling those found under oceanic breaking waves.
They next conducted trials at sea aboard a coastal research vessel, comparing their technique with standard sonar that scans the seabed in Southampton Water.

"TWIPS outperformed standard sonar in the wake of large vessels such as passenger ferries," said researcher Justin Dix at the University of Southampton.

In addition to scanning the water for targets, another use for TWIPS is its ability to detect bubbles in materials -- they weaken sediment if one wants to build bridges, for instance, and they can lead to blowouts when drilling for oil, as seen in the Deepwater Horizon disaster. Industrially, they can also look for bubbles in ceramics, glasses, plastics and other materials that can cost millions of dollars in useless — and thus wasted — products.

This method of using twinned pulses could also help remove clutter from radar as well. As such, one could use it to detect hidden electronic bugs and improvised explosive devices, or IEDs.

"I really hope that radar systems using the technique can be built that would detect IEDs in Afghanistan, as that would be very important," Leighton said.

The research is detailed in the Dec. 8 issue of the Proceedings of the Royal Society A.

Links :

• NOC : TWIPS, sonar inspired by dolphins
• YouTube : Humpback whale, hunting with bubbles technique