Saturday, August 14, 2010
Californian surfer Chuck Patterson films great white sharks circling his board
The professional surfer had spotted two sharks while out stand-up paddling surfing with a couple of friends at San Onofre beach, California.
But undeterred by their presence, the 41-year-old waterman returned the following day with a waterproof camera and stroked out to see if they would show up again.
Within a matter of minutes, the Californian found himself surrounded by a pair of Great White Sharks and caught them on video swimming just feet away from him.
At one point during his 15-minute encounter, the bigger of the two creatures – a 9ft shark – even slapped his tail on Mr Patterson’s surfboard.
Chuck Patterson, from Dana Point, California, said: “The day before I shot this video, I was stand-up paddling surfing with a couple friends and two sharks circled us for about 15 minutes.
“The next day, I decided to go back out at around the same time and take my camera mounted on a 10ft pole and do some exploring.
“Sure enough within five minutes a 9ft shark came out of nowhere and circled twice and slapped his tail on my board before disappearing.
“Then a minute later a 7ft young juvenile Great White swam circles around me for 12 minutes.”
Some of the footage shows the predators’ dorsal fins breaking the water next to him, while more menacing underwater shots see the pair swimming just feet away.
The video is likely to alarm many local surfers at San Onofre as it is not regarded as a particularly sharky spot.
The break, known for its mellow waves popular with longboarders, lies adjacent to the world-class Trestles pointbreak, on which the world’s best surfers will descend next month for the sixth contest of the ASP World Tour.
The video has become an internet hit after married Mr Patterson, a champion stand-up paddle surfer and renowned big wave rider, posted it on Vimeo, the video sharing website.
Commenting on Mr Patterson’s bravery in capturing the footage, one viewer wrote on the site: “Great big white cojones you got there Chuck.”
Posted by Peio at 2:21 AM No comments:
Friday, August 13, 2010
Google Earth for sailors and travelers
All NOAA charts seamless displayed via a GE network link
From Franck Taylor, Google Earth blog
A big part of the experience of sailing around the world is meeting up with other sailors doing similar routes.
In French Polynesia, we have had numerous opportunities to meet up with the crews of boats we have met along the way, and many new boats as well.
As a big fan of Google Earth, I have been making sure to share tips on some of the ways I am making use of Google Earth as we sail.
Many of these tips apply equally to many other forms of travel.
One thing is apparent, few people realize some of the less-known, but best features of Google Earth for travel.
Here are some important tips on Google Earth's lesser-known features that every sailor (and many other travelers) should know:
1) Google Earth can be used without an Internet connection
As we are traveling, I actually use Google Earth more without an Internet connection than with.
Many people aren't aware that Google caches the last 2 GBytes (if your cache is set to the maximum) of imagery/layers you last loaded.
What I do is visit the places I'm about to travel to (in particular the anchorages) and make sure to load the imagery of those places most important to me.
It's important not to load too large an area or the cache will start forgetting the older stuff.
Once we are on a passage (with no easy way to be on the Internet) we can still load Google Earth and view those last places loaded.
I can view what the approach to an anchorage is like, and the places we plan to visit while reading other guide materials or charts we have.
Read more about using Google Earth off the Internet / GE Help
2) The Ruler
I frequently make use of the Google Earth ruler to measure distances between places we are going, or the places we have already traveled.
You can change the units (I frequently use the "nautical miles" units) to help convert to local measures.
Also, you can trace out paths, not just single measurements (look for the tabs at the top of the window that pops up to find the "Paths" tab). This is very handy for measuring routes.
As a sailor, I often use this feature to check distances on passages, determine the best places to anchor, estimate dinghy runs, and distances we'll have to walk to grocery stores and customs offices.
3) GPS Tracks
If you have a GPS, you can take your saved GPS tracks and use many free programs to convert your track to GPX.
Some GPS programs will even output your GPS tracks directly to Google Earth's KML.
But, Google Earth will read GPX files as well. Simply open your KML or GPX file of your track.
The new Google Earth 5.2 presents you with a new option to save your file as a "track".
This lets you play back the track with some new features like the time slider.
I also recommend a free online program called "GPSVisualizer" to generate highly customized GPS tracks for use with Google Earth.
4) GPS in Real-time
Google Earth can connect directly to many GPSes.
Look for the option under "Tools->GPS".
If you have a Garmin with a USB connection, it is very simple.
You can also use the NMEA option to connect.
Read more about that in the Google Earth user guide.
Once you have your GPS connected, Google Earth can show your position in real-time.
It makes Google Earth into something like a 3D "chart plotter".
Google Earth is not to be used for navigation purposes.
The data is not intended for that, so it is not guaranteed to be accurate enough to sail by. However, using it as an additional reference has proven to be very effective.
The satellite is often (but, not always) good enough to see underwater obstructions (such as coral heads, rocks, and even sunken ships).
It has also been handy for seeing the best route through passes.
In fact, I have often found GE imagery is more accurately placed than my electronic charts.
You need to remember some of the imagery can be several years old though. The imagery is definitely not real-time (read about Google Earth imagery).
5) Many other uses
I also share our position reports, GPS tracks, and photography using Google Earth.
You can share your photos for free with Google's Panoramio - which lets you map the positions of each photo when you upload them (or you can do the geotagging with another program).
The photos will later appear on Google Earth and Google Maps for everyone to see as icons when the Panoramio/Photos layer is turned on.
I also take 360 Panoramas and upload them to 360cities.net, which are also viewable on Google Earth, or you can put them on your web site (see example).
Most importantly, I often use Google Earth while on the Internet to do research on the places we are going to find information and pictures about popular places to visit.
Turning on the Panoramio layer is a fast way to find popular places (more photos in the most interesting spots).
I also showed a bunch of sailors how to use Google Earth to show the best place to watch the solar eclipse that occurred over the central Pacific waters on July 11th.
These are just a few of the many ways I use Google Earth while sailing/traveling.
They are all free, and easily available to anyone.
All you have to know is that they exist, and how to use them.
- Marine GeoGarage blog : NOAA nautical charts in Google Earth
- 'Google Ocean' : marine mashups for Google Earth
- SFGate : Google Earth creates boat racing replays
- GPSBabel lists the devices officially supported by the GE GPS import feature
Posted by Peio at 1:48 AM 1 comment:
Thursday, August 12, 2010
Artificial ocean dead zones help predict real thing
Hypoxic zones are areas in the ocean of such low oxygen concentration that animal life suffocates and dies, and as a result are sometimes called "dead zones."
This data visualization discusses the causes of hypoxia in the Gulf of Mexico
Predicting the spread of dead zones on the seafloor could get easier if scientists know what to look for in marine life behavior.
Their solution: create a tiny, artificial dead zone that simulates how bottom dwellers fight for survival in an oxygen-deprived environment.
A small Plexiglass chamber simulated what happens in real dead zones, where dying marine life litters the seafloor after suffering oxygen starvation. Researchers placed the experimental module at the bottom of the Adriatic Sea off the coast of Slovenia.
The team then recorded how marine life struggled with their fate about 79 feet (26 meters) below the ocean surface, and made a catalogue of behaviors that could more easily provide warning signs about future dead zones.
"Our approach would allow any camera system (hand-held or sent down on a cable or attached to a remote-operated-vehicle) or divers to observe the bottom and come to conclusions without expensive sensor technologies," said study researcher Michael Stachowitsch, a marine biologist at the University of Vienna in Austria.
By contrast, expensive electronic sensors typically don't even gauge oxygen levels at the bottom of the sea where much marine life exists, Stachowitsch noted.
He added that deploying oceanographic buoys also represents a cost-intensive effort, which involves technicians, and servicing and satellite fees.
Inside the dead zone
In any case, marine biologists want better monitoring of dead zones, where dissolved oxygen in bottom waters is very low to zero, around the world.
Pollution and warming seas have already led to dead zones covering a combined area about the size of Wyoming.
Such areas often arise because of nutrient runoff from fertilizers that can lead to an explosion of algae blooms. The algae eventually dies and attracts bacteria that end up using most of the oxygen supply, which triggers mass death in the water.
Researchers from the University of Vienna, the University of Angers in France and the University of Ghent in Belgium wanted to study the phenomenon outside of the lab.
They came up with the idea of a deployable experimental module in 2005, and have since successfully used it in their latest research.
The Experimental Anoxia Generating Unit (EAGU) creates oxygen deprivation by sealing off a cubic volume almost 20 inches (50 cm) on each side. Its Plexiglass lid holds a time-lapse digital camera that takes images every six minutes, and also contains sensors that measure oxygen level and pH (the level of acidity of the water) every minute.
Researchers gathered at the Marine Biology Station in Piran, Slovenia, to deploy the boxy device. Two divers set up the EAGU so that it could monitor its artificial dead zone for up to five days at a time.
"In the lab, you can put an animal into a glass jar and record its reactions to dropping oxygen values," Stachowitsch said in an e-mail. "This will tell you very little about what that animal might actually do in the real environment, or what might happen to it in the framework of the surrounding community."
In one case, the team discovered that creatures less sensitive to oxygen deprivation, such as sea anemones, could consume more sensitive creatures such as brittle stars – at least for a time before oxygen levels dropped below what any organism could tolerate.
Under the sea
The early efforts have paid off so far, despite difficulties working underwater with delicate instruments.
"This is not a theoretical approach or a desk job," Stachowitsch said. "The depth is rather deep for regular scuba work, and the visibility is poor at the bottom, and we are at the mercy of winds and waves."
But such work becomes necessary if scientists want to understand how certain ecosystems serve the greater marine ecology, Stachowitsch said.
For instance, the bottom feeders, such as mussels, sponges, brittle stars and anemones, typically filter water and remove particles of food, and their loss can lead to more deaths among marine life.
Humans also need to figure out the value of such ecosystems, and how much it might cost to replace them with technological solutions if the natural system collapses, according to Stachowitsch.
"Today, everyone is talking about bacteria, viruses, genomics, proteomics ... but is knowledge about these things going to save our planet and save us?" Stachowitsch said. "As interesting intellectually as many of these topics are, my answer is an emphatic 'No.'"
- BBCNews : Jumbo squid survive deep ocean 'dead zones'
Posted by Peio at 1:23 AM 1 comment:
Wednesday, August 11, 2010
The jellyfish-like salp: most efficient filter-feeder in the deep, scientists discover
Salps drift, sometimes in long chains, in the open ocean.
There they are the sea's most efficient filter-feeders, grazing on food particles from large to small.
From NSF News
What if trains, planes and automobiles all were powered simply by the air through which they move? What if their exhaust and by-products helped the environment?
Such an energy-efficient, self-propelling mechanism already exists in nature.
The salp, a small, barrel-shaped organism that resembles a streamlined jellyfish, gets everything it needs from ocean waters to feed and propel itself.
Scientists believe its waste material may help remove carbon dioxide (CO2) from the upper ocean and the atmosphere.
Now researchers at the Woods Hole Oceanographic Institution (WHOI) and MIT have found that the half-inch to 5-inch-long creatures are even more efficient than had been believed.
"This innovative research is providing an understanding of how a key organism in marine food webs affects important biogeochemical processes," said David Garrison, director of the National Science Foundation (NSF)'s biological oceanography program, which funded the research.
Reporting this week in the journal Proceedings of the National Academy of Sciences (PNAS), the scientists have found that mid-ocean-dwelling salps are capable of capturing and eating extremely small organisms as well as larger ones, rendering them even hardier--and perhaps more plentiful--than had been believed.
"We had long thought that salps were about the most efficient filter-feeders in the ocean," said Larry Madin, WHOI Director of Research and one of the paper's authors.
"But these results extend their impact down to the smallest available size fraction, showing they consume particles spanning four orders of magnitude in size. This is like eating everything from a mouse to a horse."
Salps capture food particles, mostly phytoplankton, with an internal mucus filter net. Until now, it was thought that included only particles larger than the 1.5-micron-wide holes in the mesh; smaller particles would slip through.
But a mathematical model suggested salps somehow might be capturing food particles smaller than that, said Kelly Sutherland, who co-authored the PNAS paper after her PhD research at MIT and WHOI.
In the laboratory at WHOI, Sutherland and her colleagues offered salps food particles of three sizes: smaller, around the same size as, and larger than the mesh openings.
"We found that more small particles were captured than expected," said Sutherland, now a post-doctoral researcher at Caltech. "When exposed to ocean-like particle concentrations, 80 percent of the particles that were captured were the smallest particles offered in the experiment."
The finding helps explain how salps--which can exist either singly or in "chains" that may contain a hundred or more--are able to survive in the open ocean where the supply of larger food particles is low.
"Their ability to filter the smallest particles may allow them to survive where other grazers can't," said Madin.
Perhaps most significantly, the result enhances the importance of the salps' role in carbon cycling. As they eat small, as well as large, particles, "they consume the entire 'microbial loop' and pack it into large, dense fecal pellets," Madin says.
The larger and denser the carbon-containing pellets, the sooner they sink to the ocean bottom. "This removes carbon from the surface waters," said Sutherland, "and brings it to a depth where you won't see it again for years to centuries."
And the more carbon that sinks to the bottom, the more space there is for the upper ocean to accumulate carbon, hence limiting the amount that rises into the atmosphere as CO2, said paper co-author Roman Stocker of MIT.
"The most important aspect of this work is the very effective shortcut that salps introduce in the process of particle aggregation," Stocker said. "Typically, aggregation of particles proceeds slowly, by steps, from tiny particles coagulating into slightly larger ones."
"Now, the efficient foraging of salps on particles as small as a fraction of a micrometer introduces a substantial shortcut in this process, since digestion and excretion package these tiny particles into much larger particles, which thus sink a lot faster."
This process starts with the mesh made of fine mucus fibers inside the salp's hollow body.
Salps, which can live for weeks or months, swim and eat in rhythmic pulses, each of which draws seawater in through an opening at the front end of the animal. The mesh captures the food particles, then rolls into a strand and goes into the gut, where it is digested.
"It was assumed that very small cells or particles were eaten mainly by other microscopic consumers, like protozoans, or by a few specialized metazoan grazers like appendicularians," said Madin.
"This research indicates that salps can eat much smaller organisms, like bacteria and the smallest phytoplankton, organisms that are numerous and widely distributed in the ocean."
The work, also funded by the WHOI Ocean Life Institute, "implies that salps are more efficient vacuum cleaners than we thought," said Stocker.
"Their amazing performance relies on a feat of bioengineering--the production of a nanometer-scale mucus net--the biomechanics of which remain a mystery."
Posted by Peio at 1:28 AM No comments:
Tuesday, August 10, 2010
Recording the blues might explain whale speak
After three months of work, a team of San Francisco State scientists has amassed more than 4,000 recordings of underwater moans and bubbling chatter made by blue whales off the California coast - a collection that could help explain how the largest of ocean animals communicates.
Yet the scientists still don't know whether the whales' calls represent a kind of cetacean groupthink, a beacon for possible mates, or perhaps a social signal that an entire group is migrating or moving toward some new source of food.
Roger Bland, an acoustical physicist at San Francisco State University, and his colleagues have analyzed 4,378 blue whale songs recorded as the animals swam past an undersea observing station on the Pioneer Seamount, 50 miles out from Mavericks, the famed surfing spot north of Half Moon Bay.
Four hydrophones captured the loud and eerie sounds. Each is a burst of warbles, a little like someone gargling underwater, followed exactly 130 seconds later by a loud, long, deep-toned and sad-sounding moan.
Like humpbacks and fin whales, only the male blues are believed to vocalize. Yet unlike most whales, which have widely varied song repertoires, the blue whales all communicate at the same pitch, Bland said.
"We can only speculate what they mean and wonder just what adaptive advantage the (songs) may give the whales in their evolution," he said.
The songs Bland and his colleagues recorded seemed most often to be associated with either fast travel that might have happened during their migration or while they milled about near abundant masses of krill.
So far, the scientists analyzed only the long, mournful moans the whales make - known as their "B calls" - while their bubblings remain to be scrutinized.
But each of the calls made by the whales sounded exactly the same - precisely four octaves below middle C on the human scale. And where the calls did vary occasionally, their pitch differed by barely half of 1 percent. By comparison, a tiny change in human musical pitch between the notes middle C and C sharp would mark a change of fully 6 percent, a change that might go unnoticed by tone-deaf humans but would be clear to musicians.
One possibility for such mass accuracy, Bland and his colleague suggest, is that female blues may be able to locate a group of males by their sounds, which may be slightly higher or lower in pitch when the males are swimming toward the females or away from them. That effect is called the Doppler Shift - the change in pitch heard as a siren or a train whistle is nearing or speeding away.
Blue whales live in all the oceans of the world, and in each region the species and subspecies vary. But all are endangered because their numbers were decimated by worldwide hunting before international protections imposed in 1966.
They are the largest animals ever known to have lived: more than 100 feet long and weighing up to 200 tons for the south Pacific species, and somewhat less in the north Pacific.
Bland's colleagues working on this latest report include Michael D. Hoffman, a former S.F. State student, and Newell Garfield, an S.F. State oceanographer and director of the university's Romberg Tiburon Center for Environmental Studies. They published the results of their study in the July issue of the Journal of the Acoustical Society of America.
- SFStatesNews : Blue whales align the pitch of their songs with extreme accuracy, study finds
- LiveScience : Using blue whales' perfect pitch to drive people insane
Posted by Peio at 1:10 AM No comments:
Monday, August 9, 2010
Greenland glacier calves island four times the size of Manhattan
From University of Delaware
A University of Delaware researcher reports that an "ice island" four times the size of Manhattan has calved from Greenland's Petermann Glacier. The last time the Arctic lost such a large chunk of ice was in 1962.
"In the early morning hours of August 5, 2010, an ice island four times the size of Manhattan was born in northern Greenland," said Andreas Muenchow, associate professor of physical ocean science and engineering at the University of Delaware's College of Earth, Ocean, and Environment. Muenchow's research in Nares Strait, between Greenland and Canada, is supported by the National Science Foundation (NSF).
Satellite imagery of this remote area at 81 degrees N latitude and 61 degrees W longitude (position in the Marine GeoGarage), about 620 miles [1,000 km] south of the North Pole, reveals that Petermann Glacier lost about one-quarter of its 43-mile long [70 km] floating ice-shelf.
Trudy Wohlleben of the Canadian Ice Service discovered the ice island within hours after NASA's MODIS-Aqua satellite took the data on Aug. 5, at 8:40 UTC (4:40 EDT), Muenchow said.
These raw data were downloaded, processed, and analyzed at the University of Delaware in near real-time as part of Muenchow's NSF research.
Petermann Glacier, the parent of the new ice island, is one of the two largest remaining glaciers in Greenland that terminate in floating shelves. The glacier connects the great Greenland ice sheet directly with the ocean.
The new ice island has an area of at least 100 square miles and a thickness up to half the height of the Empire State Building.
"The freshwater stored in this ice island could keep the Delaware or Hudson rivers flowing for more than two years. It could also keep all U.S. public tap water flowing for 120 days," Muenchow said.
The island will enter Nares Strait, a deep waterway between northern Greenland and Canada where, since 2003, a University of Delaware ocean and ice observing array has been maintained by Muenchow with collaborators in Oregon (Prof. Kelly Falkner), British Columbia (Prof. Humfrey Melling), and England (Prof. Helen Johnson).
"In Nares Strait, the ice island will encounter real islands that are all much smaller in size," Muenchow said. "The newly born ice-island may become land-fast, block the channel, or it may break into smaller pieces as it is propelled south by the prevailing ocean currents. From there, it will likely follow along the coasts of Baffin Island and Labrador, to reach the Atlantic within the next two years."
The last time such a massive ice island formed was in 1962 when Ward Hunt Ice Shelf calved a 230 square-mile island, smaller pieces of which became lodged between real islands inside Nares Strait.
Petermann Glacier spawned smaller ice islands in 2001 (34 square miles) and 2008 (10 square miles). In 2005, the Ayles Ice Shelf disintegrated and became an ice island (34 square miles) about 60 miles to the west of Petermann Fjord.
- Wired : Enormous ice block breaks off Greenland glacier
Posted by Peio at 1:15 AM 3 comments:
Sunday, August 8, 2010
Sable island : the graveyard of the Atlantic
From Maritime Museum of the Atlantic
Sable Island, a 44-km-long sand bar about 150 miles east south east of Halifax, Nova Scotia, is renowned for its wild horses (position in the Marine GeoGarage).
For sailors, it was the graveyard of the Atlantic, an island hidden by waves, storms and fog that meant only death and destruction.
Since 1583 there have been over 350 recorded shipwrecks on Sable Island.
Very little now remains of the ships that were wrecked on the island: a shoe buckle, a few coins, ship name boards, timbers buried in the sand.
Why so many wrecks?
- Location: Sable lies near one of the world's richest fishing grounds. It is also near one of the major shipping routes between Europe and North America. Hundreds of vessels sailed past each year.
- It's a very stormy place: Sable lies right in the path of most storms that track up the Atlantic coast of North America. Storms were extremely treacherous for sailing ships. Vessels were simply blown onto Sable.
- Fog shrouds the island: in summer warm air from the Gulf Stream produces dense banks of fog when it hits air cooled by the Labrador Current around Sable. Sable has 125 days of fog a year. Toronto has 35.
- The currents around Sable are tricky: Sable lies near the junction of three major ocean currents, the Gulf Stream, the Labrador Current and the Belle Isle Current.
Prior to then the sextant was the principal instrument used to fix a ship's position.
Sextants were accurate, but they worked by taking a sighting from the sun or the stars.
They were useless in dense fog or cloudy skies.
In bad weather, the captain navigated by "dead reckoning", using the ship's speed and direction to estimate his position.
But even in good conditions this was educated guessing.
Currents and storms confused the calculations of the best skippers.
Many accounts of shipwrecks report that the captain simply lost his way: he misjudged his ship's position and bumped into Sable Island by mistake.
After World War II radar and other advanced navigational equipment became widely used on commercial vessels.
Sable ceased to be a major threat to shipping.
Only one vessel has been lost since 1947, the small yacht Merrimac which sank on July 27, 1999.
- Sable island : a story of survival
- Strange map : the graveyard of the Atlantic
- Virtual Museum
Posted by Peio at 1:10 AM No comments:
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