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1,000 Feet Down: Man Sets New Deep-Dive Record

1,000 Feet Down: Man Sets New Deep-Dive Record
An Egyptian man recently took the ultimate plunge for the sake of science. Setting a new Guinness World Record for the deepest scuba dive, the man dove more than 1,000 feet (305 meters) below the surface of the Red Sea.

When asked why he decided to dive deeper than any person had before, Ahmed Gabr, 41, told the media that he was hoping to prove that humans could survive the conditions of deep sea immersion, according to Guinness World Records.

Diving off the coast of Dahab, Egypt, Gabr reached a depth of 1,090 feet 4 inches (332.35 meters). The previous record holder for the deepest scuba dive, Nuno Gomes of South Africa, also dove off the coast of Dahab, in 2005, reaching a depth of 1,044 feet (318.21 m).

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New 3D Map of Civil War Shipwreck Released

New 3D Map of Civil War Shipwreck Released
On this day (Jan. 11) in 1863, a Union warship was sunk in a skirmish with a Confederate vessel in the Gulf of Mexico.

Exactly 150 years later, a new 3D map of the USS Hatteras has been released that shows what the remains of the warship look like. The Hatteras rests on the ocean floor about 20 miles (32 kilometers) off Galveston, Texas, according to a release from the National Oceanographic and Atmospheric Administration, which helped to sponsor the expedition to map the shipwreck.

The Hatteras was sunk in a battle with the Confederate raider CSS Alabama, and was the only Union warship sunk in combat in the Gulf of Mexico during the Civil War.

In the image above, the 3D sonar view of the USS Hatteras is from the vessel's port (left) side. More than half the hull lays buried in sediment. The curved tooth-like outline to the right is the remains of the stern and rudder.

 Credit: NOAA's Office of National Marine Sanctuaries/ExploreOcean et al 

 

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Silfra, the fissure between the continents

The Silfra fissure, is known as one of the top dive sites in the world two main reasons.

First, the Silfra fissure is actually a crack between the North American and Eurasian continents, meaning that you dive or snorkel right where the continental plates meet and drift apart about 2cm per year.

Silfra is the only place where one can dive or snorkel directly in the crack between two continental plates.

Secondly, the underwater visibility in the Silfra fissure is over 100 meters, which creates an underwater experience that will rarely, if ever, be surpassed. The reasons for this astounding water clarity are twofold: the water is cold (2°C – 4°C year round ) as it is glacial water from the nearby Langjökull and this water is filtered through porous underground lava for 30-100 years until it reaches the north end of Thingvellir lake, seeping out from underground wells. The Silfra water is as pristine as water can get and you can drink it at anytime during your dive or snorkel.

The Silfra fissure consists of four sections: Silfra Big Crack, Silfra Hall, Silfra Cathedral, and Silfra Lagoon.  We plan our dives and snorkel swims so that we are able to see all Silfra sections in every Diving Silfra Day Tour and our Silfra Snorkeling Tour.  We enter the water from a platform with steps leading down.  If you are diving, the maximum depth of the your dive in Silfra will be 18 meters, but the average depth of the dive is between 7 and 12 meters.

Although Thingvellir Lake has an abundance of fish species and trout fishing is very popular in the lake, the fish usually do not venture far into the Silfra fissure.  The marine life in Silfra consists mostly of bright green “troll hair” and different types of algae that provide a colorscape unlike anything that occurs naturally above the surface.

The National Park Thingvellir has been declared a UNESCO WORLD HERITAGE SITE both for its cultural and historical significance as well as natural and geological uniqueness.  It is well worth it to join our Golden Circle Day Tour to further explore Thingvellir on land.  Moreover, if you have friends or family accompanying you on your tour but do not wish to get in the water themselves, the area around Silfra is full of lovely walking trails that lead through this fascinating place.

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Survive Your Dive

"Nobody understands the allure of the sea more than the U.S. Coast Guard, but we also see the tragic results when people underestimate the hazards. The adventure and thrill of diving are appealing to many, but the ocean is an unforgiving environment — and even less forgiving to those who recreate beneath the surface."

— Rear Adm. Karl Schultz, commander of the 11th Coast Guard District

Recreational diving is by and large a safe activity, but when accidents occur the outcomes are often frightening and can be fatal. The beautiful blue world below can quickly become hostile for divers who lack adequate training, are in poor physical condition, use improperly maintained equipment or are otherwise unprepared.

Although the U.S. Coast Guard does not have regulatory authority over recreational diving as it does for recreational and commercial boating, Coast Guard search-and-rescue crews are frequently called on to assist when divers are lost or in trouble. In the aftermath of a dive injury or death, the Coast Guard marine casualty investigators work with other public health and safety organizations to identify what went wrong and evaluate how to prevent future accidents.

In 2009 the Coast Guard began to forge strong partnerships with the San Diego Lifeguard Services, the San Diego Harbor Police, the San Diego County Medical Examiner's Office, the University of California San Diego Health System and the Scripps Institution of Oceanography to analyze dive incidents. The committee formed by these groups produced six recommendations based on a comprehensive review of diver fatalities in the San Diego area. The committee encourages divers everywhere to ask themselves the following questions:

1. Is your training adequate for the current and predicted conditions? Will you respect the limitations created by the conditions and stop diving when conditions change or exceed your personal limits?All the normal hazards of water sports are magnified for those who spend time beneath the surface. Strong currents can occur at any time of year. Cold water temperatures, limited air supply, reliance on equipment for survival and the lack of underwater rescue capabilities make it essential that divers are fully aware of their limits and prepared for all possible problems.

2. Are you prepared to abandon your weights, inflate your buoyancy compensator and signal for help when in distress?Divers should not be afraid to ditch their weights, end their dives and signal for help at the first signs of distress. Interviews with divers who have experienced distress reveal that many of them did not understand they were in danger because they had not been taught how it would feel; therefore, divers should signal for help if they have any concerns at all.

3. Is your physical fitness adequate for the current and predicted conditions? Have you checked with your primary doctor to ensure that you are in good enough health for intense physical exertion? Diving is a strenuous physical activity involving physiological demands unlike those of any other sport. Many dive fatalities are caused by heart attacks, and the risk is especially great for divers over the age of 45. Divers who have not dived in more than a year should consult with their primary-care physicians before attempting to return to the sport. They should then reassess their abilities with a simple or less-challenging dive.

4. Are you diving with a buddy? Have you reviewed each other's abilities, equipment and plans?In addition to planning, health, physical fitness and awareness of weather and sea conditions, dive-safety experts stress the importance of the buddy system. Divers should never dive alone. They should always have detailed plans (which include times and locations) that they share with someone ashore.

5. Do you feel completely comfortable making this dive?It is essential to prioritize safety and remain realistic about upcoming dives. Any hesitations about any aspect of a dive should be completely resolved prior to commencing the dive. Divers should also clearly understand their experience levels and only attempt to exceed these limits when the conditions are optimal and they are diving with more experienced partners.

6. Do you plan to enter overhead environments? If so, do you have the proper training and equipment, and are you familiar with the necessary procedures?Diving in caves, wrecks or any overhead environments in which the path to the surface is indirect necessitates additional training, equipment and air supply. In overhead environments, prepare yourself for confined spaces, entanglement and disorientation.

According to the Coast Guard's Tactical and Strategic Statistics, in the past four years (2010-2013) the Coast Guard was called for assistance in 63 fatal dive accidents and 55 diving-related injuries. We hope that publishing these safety tips will lead to fewer dive-related tragedies. "The Coast Guard doesn't regulate recreational diving but is generally called in to assist during diving emergencies," Schultz said. "In many of these dive emergencies, injuries and death are preventable. We want everyone who enjoys the water, including divers (whose sport leaves little room for error), to make safety their top priority. We want you to survive your dive."

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Shipwreck hunters stumble across mysterious find

Deep down on the bottom of the Baltic Sea, Swedish treasure hunters think they have made the find of a lifetime.

The problem is, they're not exactly sure what it is they've uncovered.

Out searching for shipwrecks at a secret location between Sweden and Finland, the deep-sea salvage company Ocean Explorer captured an incredible image more than 80 meters below the water's surface.

At first glance, team leader and commercial diver Peter Lindberg joked that his crew had just discovered an unidentified flying object, or UFO.

"I have been doing this for nearly 20 years so I have a seen a few objects on the bottom, but nothing like this," said Lindberg.

"We had been out for nine days and we were quite tired and we were on our way home, but we made a final run with a sonar fish and suddenly this thing turned up," he continued.

I have been doing this for nearly 20 years so I have a seen a few objects on the bottom, but nothing like this
Peter Lindberg, team leader Ocean Explorer.

Using side-scan sonar, the team found a 60-meter diameter cylinder-shaped object, with a rigid tail 400 meters long.

The imaging technique involves pulling a sonar "towfish" -- that essentially looks sideways underwater - behind a boat, where it creates sound echoes to map the sea floor below.

On another pass over the object, the sonar showed a second disc-like shape 200 meters away.

See also: Quest for Sir Francis Drake's remains

Lindberg's team believe they are too big to have fallen off a ship or be part of a wreck, but it's anyone's guess what could be down there.

"We've heard lots of different kinds of explanations, from George Lucas's spaceship -- the Millennium Falcon -- to 'it's some kind of plug to the inner world,' like it should be hell down there or something.

"But we won't know until we have been down there," said Lindberg.

The Head of Archaeology at Sweden's Maritime Museums, Andreas Olsson, admits he's intrigued by the picture, but remains sceptical about what it could be.

The reliability of one-side scan sonar images is one of his main concerns, making it difficult to determine if the object is a natural geological formation or something different altogether.

"It all depends on the circumstances when you actually tow the [sonar] fish after the boat," he said.

"What are the temperature conditions, the wave conditions, how deep is your fish in relation to the sea bed etcetera and all those parameters also affects what kind of image you have in the end," he explained.

Even Lindberg agrees the image "isn't the best it could be." But his crew are still planning to return to the site in the calmer waters of spring to investigate their find.

It's a risky and expensive business, and not one that always pays off.

British maritime historian, Professor Andrew Lambert, says the costs of recovery are now too high for most.

If you want to stand in a cold shower tearing up £50 notes, go shipwreck hunting.
Professor Andrew Lambert, British maritime historian.

"If you want to stand in a cold shower tearing up £50 notes, go shipwreck hunting," he said. "Most shipwrecks are rotting away, or carrying dull things -- all the romance has been taken out of it."

It's a problem Lindberg and his team are aware of.

"It's a very difficult industry to be in -- it's money all the time," he confessed. "The best thing it could be, would be 60 meters of gold -- then I would be very happy."

"This thing is very far out, it's really off-shore, so first of all we need a bigger ship... more equipment.. and we have to do bottom sampling, water sampling, to see if it is something poisonous."

But even if the mystery object doesn't contain retrievable treasure the site could still prove to be a gold mine for the Ocean Explorer team, with tourists and private investors paying to see it up-close, in a submarine.

"The object itself is maybe not valuable in the sense of money it can be very interesting whatever it is, historical or a natural anomaly," said Lindberg.

In the North Atlantic, one American salvage company is also hoping to beat the odds.

Using side-scan sonar, the team found a 60-meter diameter cylinder-shaped object, with a rigid tail 400 meters long.
Using side-scan sonar, the team found a 60-meter diameter cylinder-shaped object, with a rigid tail 400 meters long.

Odyssey Marine Exploration -- a company made up of researchers, scientists, technicians and archaeologists -- have at least 6,300 shipwrecks in their database that they are looking to find.

Their latest discoveries include two British war-time shipwrecks off the coast of Ireland that could be laden with hundreds of tonnes of silver.

Mark Gordon, president of Odyssey, says at least 100 ships on their watch-list are known to have values in excess of $50 million dollars.

"When you think about the fact until the mid 20th century, the only way to transport wealth was on the oceans and a lot of ships were lost, it adds up to a formula where we have billions of dollars worth of interesting and valuable things on the sea floor," he said.

The lure of treasure has lead to an increasing number of discoveries in recent years. But one which doesn't come without its dangers, warns Olsson.

"I think recently we're entering a time of a lot of discoveries," he said of the technological advancements in finding shipwrecks.

"The professional shipwreck discoverers are doing a great effort for cultural heritage management in the long run... what we don't support is the action of actually taking up items and selling them," he said.

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Drink up! 200-year-old booze found in shipwreck

The 200-year-old Selters bottle contained alcohol that is likely a gin or vodka
The 200-year-old Selters bottle contained alcohol that is likely a gin or vodka. (Photo: National Maritime Museum GdaÅ„sk)
 
A 200-year-old stoneware seltzer bottle that was recently recovered from a shipwreck at the bottom of the Baltic Sea contains alcohol, according to the results of a preliminary analysis.
 
Researchers discovered the well-preserved and sealed bottle in June, while exploring the so-called F53.31 shipwreck in Gdańsk Bay, close to the Polish coast. Preliminary laboratory tests have now shown the bottle contains a 14-percent alcohol distillate, which may be vodka or a type of gin called jenever, most likely diluted with water.
 
The chemical composition of the alcohol corresponds to that of the original brand of "Selters" water that is engraved on the bottle, according to the National Maritime Museum in Gdańsk, Poland.
 
The bottle is embossed with the word "Selters," the name of a supplier of high-quality carbonated water from the Taunus Mountains area in Germany. Water from Selters was discovered about 1,000 years ago, which makes it one of the oldest types of mineral water in Europe, and one whose alleged health benefits are legendary. [See Images of the Seltzer Bottle and Baltic Shipwreck]
 
"The bottle dates back to the period of 1806-1830 and has been recovered during the works on the F-53-31 shipwreck, or the so-called GÅ‚azik," which in Polish means a small rock, Tomasz Bednarz, an underwater archaeologist the National Maritime Museum who leads the research on the shipwreck, said in a statement last month.
 
The bottle, which has a capacity of about 1 liter (34 ounces), was manufactured in Ranschbach, Germany, a town located about 25 miles (40 kilometers) away from the springs of Selters water.
 
In addition to the bottle, researchers exploring the shipwreck also recovered fragments of ceramics, a small bowl, a few pieces of dinnerware, stones and rocks, Bednarz said.
 
At the beginning of July, researchers submitted the bottle and its contents for testing to the J.S. Hamilton chemical laboratory in Gdynia, Poland, to see if the vessel contained original "Selters" water, or whether it had been refilled with a different liquid. The final results of the laboratory analysis are expected to be completed at the beginning of September, though their preliminary results suggest the bottle had been refilled with some kind of alcohol.
 
How does it taste? Apparently, the alcohol is drinkable, the archaeologists involved told the news site of Poland's Ministry of Science and Science Education. "This means it would not cause poisoning. Apparently, however, it does not smell particularly good," Bednarz said, according to the Ministry.
 
The springs of Selters water eventually went dry at the beginning of the 19th century, and therefore the water became much harder to obtain, according to the National Maritime Museum in Gdańsk.
 
In 1896, a group of Selters residents decided to look for new sources of the legendary water, and, after they made multiple boreholes, a fountain of water exploded from one of the wells in an area near a local castle.
 
These days, Selters is sold as a luxury product. Although glass bottles have replaced the stoneware bottles, the water quality is believed to be the same as it was when the water was originally discovered.
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Nature's tiny engineers: Corals control their environment, stirring up water eddies to bring nutrients

Vortical ciliary flows enhance the exchange of oxygen and nutrients between corals and their environment. The paths of tracer particles are color-coded by fluid velocity, demonstrating that the coral surface is driving the flow.   Credit: Courtesy of the researchers

Conventional wisdom has long held that corals -- whose calcium-carbonate skeletons form the foundation of coral reefs -- are passive organisms that rely entirely on ocean currents to deliver dissolved substances, such as nutrients and oxygen. But now scientists at MIT and the Weizmann Institute of Science (WIS) in Israel have found that they are far from passive, engineering their environment to sweep water into turbulent patterns that greatly enhance their ability to exchange nutrients and dissolved gases with their environment.

"These microenvironmental processes are not only important, but also unexpected," says Roman Stocker, an associate professor of civil and environmental engineering at MIT and senior author of a paper describing the results in the Proceedings of the National Academy of Sciences.

When the team set up their experiment with living coral in tanks in the lab, "I was expecting that this would be a smooth microworld, there would be not much action except the external flow," Stocker says. Instead, what the researchers found, by zooming in on the coral surface with powerful microscopes and high-speed video cameras, was the opposite: Within the millimeter closest to the coral surface, "it's very violent," he says.

It's long been known that corals have cilia, small threadlike appendages that can push water along the coral surface. However, these currents were previously assumed to move parallel to the coral surface, in a conveyor-belt fashion. Such smooth motion may help corals remove sediments, but would have little effect on the exchange of dissolved nutrients. Now Stocker and his colleagues show that the cilia on the coral's surface are arranged in such a way as to produce strong swirls of water that draw nutrients toward the coral, while driving away potentially toxic waste products, such as excess oxygen.

Not just passive

"The general thinking has been that corals are completely dependent upon ambient flow, from tides and turbulence, to enable them to overcome diffusion limitation and facilitate the efficient supply of nutrients and the disposal of dissolved waste products," says Orr Shapiro, a postdoc from WIS and co-first author on the paper, who spent a year in Stocker's lab making these observations.

Under such a scenario, colonies in sheltered parts of a reef or at slack tide would see little water movement and might experience severe nutrient limitation or a buildup of toxic waste, to the point of jeopardizing their survival. "Even the shape of the coral can be problematic" under that passive scenario, says Vicente Fernandez, an MIT postdoc and co-first author of the paper. Coral structures are often "treelike, with a deeply branched structure that blocks a lot of the external flow, so the amount of new water going through to the center is very low."

The team's approach of looking at corals with video microscopy and advanced image analysis changed this paradigm. They showed that corals use their cilia to actively enhance the exchange of dissolved molecules, which allows them to maintain increased rates of photosynthesis and respiration even under near-zero ambient flow.

The researchers tested six different species of reef corals, demonstrating that all share the ability to induce complex turbulent flows around them. "While that doesn't yet prove that all reef corals do the same," Shapiro says, "it appears that most if not all have the cilia that create these flows. The retention of cilia through 400 million years of evolution suggests that reef corals derive a substantial evolutionary advantage" from these flows.

Corals need to stir it up

The reported findings transform the way we perceive the surface of reef corals; the existing view of a stagnant boundary layer has been replaced by one of a dynamic, actively stirred environment. This will be important not only to questions of mass transport, but also to the interactions of marine microorganisms with coral colonies, a subject that attracts much attention due to a global increase in coral disease and reef degradation over the past decades.

Besides illuminating how coral reefs function, which could help better predict their health in the face of climate change, this research could have implications in other fields, Stocker suggests: Cilia are ubiquitous in more complex organisms -- such as inside human airways, where they help to sweep away contaminants.

But such processes are difficult to study because cilia are internal. "It's rare that you have a situation in which you see cilia on the outside of an animal," Stocker says -- so corals could provide a general model for understanding ciliary processes related to mass transport and disease.

David Bourne, a researcher at the Australian Institute of Marine Science who was not connected with this research, says the work has "provided a major leap forward in understanding why corals are so efficient and thrive. … We finally have a greater understanding of why corals have been successful in establishing and providing the structural framework of coral reef ecosystems."

Bourne adds that Stocker has made great strides by "applying his engineering background to biological questions. This cross-disciplinary approach allows his group to approach fundamental questions from a new angle and provide novel answers."

In addition to Stocker, Shapiro, and Fernandez, the research team included Assaf Vardi, faculty at WIS; postdoc Melissa Garren; former MIT postdoc Jeffrey Guasto, now an assistant professor at Tufts University; undergraduate François Debaillon-Vesque from MIT and the École Polytechnique in Paris; and Esti Kramarski-Winter from WIS. The work was supported by the Human Frontiers in Science Program, the National Science Foundation, the National Institutes of Health, and the Gordon and Betty Moore Foundation.

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Nature's tiny engineers: Corals control their environment, stirring up water eddies to bring nutrients

Vortical ciliary flows enhance the exchange of oxygen and nutrients between corals and their environment. The paths of tracer particles are color-coded by fluid velocity, demonstrating that the coral surface is driving the flow.   Credit: Courtesy of the researchers

Conventional wisdom has long held that corals -- whose calcium-carbonate skeletons form the foundation of coral reefs -- are passive organisms that rely entirely on ocean currents to deliver dissolved substances, such as nutrients and oxygen. But now scientists at MIT and the Weizmann Institute of Science (WIS) in Israel have found that they are far from passive, engineering their environment to sweep water into turbulent patterns that greatly enhance their ability to exchange nutrients and dissolved gases with their environment.

"These microenvironmental processes are not only important, but also unexpected," says Roman Stocker, an associate professor of civil and environmental engineering at MIT and senior author of a paper describing the results in the Proceedings of the National Academy of Sciences.

When the team set up their experiment with living coral in tanks in the lab, "I was expecting that this would be a smooth microworld, there would be not much action except the external flow," Stocker says. Instead, what the researchers found, by zooming in on the coral surface with powerful microscopes and high-speed video cameras, was the opposite: Within the millimeter closest to the coral surface, "it's very violent," he says.

It's long been known that corals have cilia, small threadlike appendages that can push water along the coral surface. However, these currents were previously assumed to move parallel to the coral surface, in a conveyor-belt fashion. Such smooth motion may help corals remove sediments, but would have little effect on the exchange of dissolved nutrients. Now Stocker and his colleagues show that the cilia on the coral's surface are arranged in such a way as to produce strong swirls of water that draw nutrients toward the coral, while driving away potentially toxic waste products, such as excess oxygen.

Not just passive

"The general thinking has been that corals are completely dependent upon ambient flow, from tides and turbulence, to enable them to overcome diffusion limitation and facilitate the efficient supply of nutrients and the disposal of dissolved waste products," says Orr Shapiro, a postdoc from WIS and co-first author on the paper, who spent a year in Stocker's lab making these observations.

Under such a scenario, colonies in sheltered parts of a reef or at slack tide would see little water movement and might experience severe nutrient limitation or a buildup of toxic waste, to the point of jeopardizing their survival. "Even the shape of the coral can be problematic" under that passive scenario, says Vicente Fernandez, an MIT postdoc and co-first author of the paper. Coral structures are often "treelike, with a deeply branched structure that blocks a lot of the external flow, so the amount of new water going through to the center is very low."

The team's approach of looking at corals with video microscopy and advanced image analysis changed this paradigm. They showed that corals use their cilia to actively enhance the exchange of dissolved molecules, which allows them to maintain increased rates of photosynthesis and respiration even under near-zero ambient flow.

The researchers tested six different species of reef corals, demonstrating that all share the ability to induce complex turbulent flows around them. "While that doesn't yet prove that all reef corals do the same," Shapiro says, "it appears that most if not all have the cilia that create these flows. The retention of cilia through 400 million years of evolution suggests that reef corals derive a substantial evolutionary advantage" from these flows.

Corals need to stir it up

The reported findings transform the way we perceive the surface of reef corals; the existing view of a stagnant boundary layer has been replaced by one of a dynamic, actively stirred environment. This will be important not only to questions of mass transport, but also to the interactions of marine microorganisms with coral colonies, a subject that attracts much attention due to a global increase in coral disease and reef degradation over the past decades.

Besides illuminating how coral reefs function, which could help better predict their health in the face of climate change, this research could have implications in other fields, Stocker suggests: Cilia are ubiquitous in more complex organisms -- such as inside human airways, where they help to sweep away contaminants.

But such processes are difficult to study because cilia are internal. "It's rare that you have a situation in which you see cilia on the outside of an animal," Stocker says -- so corals could provide a general model for understanding ciliary processes related to mass transport and disease.

David Bourne, a researcher at the Australian Institute of Marine Science who was not connected with this research, says the work has "provided a major leap forward in understanding why corals are so efficient and thrive. … We finally have a greater understanding of why corals have been successful in establishing and providing the structural framework of coral reef ecosystems."

Bourne adds that Stocker has made great strides by "applying his engineering background to biological questions. This cross-disciplinary approach allows his group to approach fundamental questions from a new angle and provide novel answers."

In addition to Stocker, Shapiro, and Fernandez, the research team included Assaf Vardi, faculty at WIS; postdoc Melissa Garren; former MIT postdoc Jeffrey Guasto, now an assistant professor at Tufts University; undergraduate François Debaillon-Vesque from MIT and the École Polytechnique in Paris; and Esti Kramarski-Winter from WIS. The work was supported by the Human Frontiers in Science Program, the National Science Foundation, the National Institutes of Health, and the Gordon and Betty Moore Foundation.

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What It's Like To Dive In Near Freezing Water

Usually there’s some sort of payoff to diving in near-freezing conditions — a magnificent wreck perhaps, or a unique geological feature. I wasn’t so lucky. When I first dived in 37-degree water, in a shallow lake outside London, there was nothing. Well, that’s not quite accurate: At one point I think I spotted a traditional British black taxi through the murk. But I couldn’t be sure — with visibility of only 20 feet, it was hard to tell.

It was so cold, I could barely think. This was problematic because I was there to make the open-water dives for my PADI Dry Suit Diver qualification and needed my wits about me. The water temperature at Wray Bury Dive Centre’s 15-acre lake is always on the chilly side — this is England, after all — but 37 degrees was unusual. A cold snap the week before caused the surface of the lake to freeze, though it had begun to melt by the time of my visit.

Taking my first steps into the lake was just about bearable. It was when my hands — protected by only 3 mm of neoprene — touched the water that I got a sense of just how hard this was going to be. But that was nothing compared to the brain freeze that struck as I made my first descent. I’m a confident, experienced diver, not prone to panic, but the feeling of ice-cold water surrounding my head and neck was too much. I motioned desperately to the instructor that I needed to surface, and came up, my breathing shallow and hurried.

He helped me to calm down, and we soon rejoined the rest of the group on a platform at 22 feet to complete the skill tests. That dive, and the follow-up that afternoon, were kept to just 20 minutes’ bottom time due to the cold. Even so, I had such limited feeling in my fingers by the time I came up for the skill tests that basic tasks — like undoing the clips on my BC or disconnecting and reconnecting my dry suit second stage — were enormously challenging. It took several attempts, with a great deal of motivational support from my instructor, to demonstrate the skills successfully.

Writing about the experience today while I’m warm and dry, it’s hard to even conjure that unexpectedly extreme environment. They are still the hardest dives I’ve ever made.

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Diving Impaired: Nitrogen Narcosis

It's true what they say, getting narced is fun — of a certain kind. Similar to drinking way too much, then driving waaay too fast. As in, "Whoa, dude, you almost hit that tree! Hahahaha!"

Which should indicate the downside. Not to sound like your mother here, but nitrogen narcosis is, in fact, drunk diving. Though you hear a lot about decompression illness, getting narced should probably be a bigger worry, at least when you dive below 100 feet. At that depth, nitrogen narcosis becomes more likely than a DCI hit, and when it occurs it is more dangerous because it attacks your most important piece of life-support equipment: your brain. That, not DCI, is the primary reason for the traditional recreational depth limit of 130 feet. But there's good news too: You can manage this risk and still dive safely below 100 feet.

What Is Nitrogen Narcosis?

You probably know the term "rapture of the deep" and have heard stories of divers offering their regs to fish and so on. Inappropriate euphoria and general silliness are the best known symptoms of nitrogen narcosis, though narcosis can also trigger anxiety, even terror. The exact mechanism is not well understood, but it's probably no coincidence that the usual symptoms resemble the early stages of general anesthesia. Compare, for example, the effects of the common dental anesthetic nitrous oxide, called laughing gas. "The same kinds of mechanisms are involved," says Dr. Peter B. Bennett, author of the chapter on inert gas narcosis in Alfred Bove's Diving Medicine. "General anesthesia and nitrogen narcosis both occur when a given anesthetic gas — and I would include nitrogen as one — reaches a certain critical molar concentration." In fact, nitrogen narcosis "may be considered as a state of impending general anesthesia" according to the authors of Diving and Subaquatic Medicine. Not the best mental state, probably, with 100 feet of water over your head.

Nitrogen narcosis has also been compared to alcoholic intoxication, the so-called "Martini Law" — each 50 feet of descent is equivalent to drinking one martini. Your thinking slows down. Your inhibitions and self-control are reduced, allowing euphoria or anxiety to emerge. Perceptual narrowing and a tendency to become fixed on one idea are common. Nitrogen narcosis, like alcohol, also impairs your motor control and memory. If it progresses far enough, you become unconscious. Precisely which mental functions are impaired, in what order and to what degree are debated by researchers, and studies have yielded conflicting results. What everyone agrees on, however, is that nitrogen narcosis degrades your ability to react quickly to a crisis and reason your way out of it.

Not You? You Wish

You've been below 100 feet many times and you've never been narced? Maybe. Divers, like drinkers, vary widely in their susceptibility, and you may in fact be more resistant to narcosis than some others. But it's hard to know that for sure based on your subjective feelings. "One of the biggest effects of nitrogen narcosis is an amnesia of what happened when you were down there," says Bennett. "Divers don't even remember what they were like." So you may have been more narced than you remember. Add forgetfulness to overconfidence and recklessness, other important effects of nitrogen narcosis, and you're like the guy leaving the party after a few too many who insists he's OK to drive. He has done it before and may do it again, but only if he's not called upon to react to a sudden emergency like a sharp curve and a stout tree.

Nitrogen narcosis is related to the partial pressure of the nitrogen in your gas mix, so narcosis becomes more likely as you go deeper. You may as well say nitrogen narcosis is caused by going deep. The threshold for significant narcosis on air is often said to be 100 feet, but that's only a rough guide. Actually, narcosis probably begins to appear as soon as you leave the surface. For example, a Navy test found slight but measurable effects at only 33 feet. It's a lot like asking what blood alcohol level constitutes drunk driving. The law states a number, though everyone knows there is some effect on your reaction time at lower levels.

Nitrogen and alcohol are different in some ways too. Serious, noticeable narcosis comes on more quickly whenever you reach your personal threshold depth. Studies show it reaches a peak within two minutes, and does not get worse even after three hours at that depth. It goes away very quickly as you ascend, and totally disappears before you reach the surface. As far as anyone knows, nitrogen narcosis, unlike alcohol abuse, does not do long-term harm and leaves no hangover. However, it's not what narcosis itself does to you that you should worry about, it's the harm you can do yourself because you're too narced to think clearly.

Many Unknowns

Different divers feel different amounts of narcosis at the same depth. The same diver may feel different amounts of narcosis at the same depth on different days. Narcosis takes different forms, too. Just as there are happy drunks, sad drunks and angry drunks, some divers are euphoric when narced, but some are terrified and some are just confused.

Some of the variables affecting all divers are:

  • Interaction with drugs. It is well-known that several drugs can interact in surprisingly intense ways, so that 1 + 1 equals 3. Some drugs, including anti-motion sickness pills, may interact with nitrogen to increase your narcosis susceptibility and intensity. Not much research has been done, but Bennett suggests that if a drug would increase the effect of alcohol, it's a reasonable assumption that it might increase nitrogen narcosis.
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  • Interaction with alcohol. Drinking and diving is never a good idea, of course, and some experts think the nitrogen/alcohol interaction may be especially strong because they have similar effects on your nervous system--1 + 1 may equal 5, in other words. Even a hangover can potentiate nitrogen narcosis.
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  • Interaction with carbon dioxide. Among the intensifiers of nitrogen narcosis, "carbon dioxide is a big one," says Bennett. "High levels of carbon dioxide in your blood are going to work with nitrogen to make narcosis worse." Elevated carbon dioxide levels generally result from rapid, heavy breathing. You may be working hard--finning into a current, for example--or sucking on a poorly performing regulator. Anxiety is another cause of rapid breathing and therefore high carbon dioxide.
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  • Fatigue. Doing heavy work at depth seems to bring on nitrogen narcosis, though whether that's because of the elevated carbon dioxide that usually goes with hard work or is an independent effect of being tired is not clear.
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  • Task-loading, time stress. Trying to do too many things, or trying to do too much in a short time, also increases the narcosis effect. Again, whether this is a carbon dioxide effect caused by the anxiety of trying to cope with too many tasks or an independent effect is not clear.
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  • Cold. Being cold is often mentioned as a contributing cause of nitrogen narcosis. The reasons aren't known, but some of the effects of hypothermia are similar to those of narcosis, including mental dulling, sluggishness and amnesia.
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In addition to the variables that affect all divers, some divers seem to be more susceptible to nitrogen narcosis than others. Obviously the relaxed, healthy diver with good breathing habits and a low air consumption rate has an advantage over the nervous, heavy breather. Also, some experts think highly intelligent and emotionally stable divers are less susceptible to nitrogen narcosis.

Adaptation to Narcosis

Most divers who regularly go very deep on air are convinced that they become adapted to it and after a while have less trouble with nitrogen narcosis. Is it true physical adaptation (meaning the divers are actually less narced) or have the divers just learned to compensate better for it? That's another unknown. The adaptation, if that's what it is, is temporary. Most say it wears off in about five days.

In any event, common practice among divers who must go very deep using air is to work up to the depth by making the first dive of each day progressively deeper. In 1989, Bret Gilliam set a depth record on air of 452 feet, and worked down to the depth with more than 600 dives, at least 100 of them deeper than 300 feet. As a result, Gilliam was not so narced at 452 feet that he could not do a series of math problems and, more to the point, return to the surface alive.

How Deep Is Too Deep?

Gilliam's 452 feet on air is off the chart for the rest of us. Various studies have described the narcotic effect of air at 300 feet as "stupefaction," "severe narcosis," "marked impairment of practical ability and judgment," and even unconsciousness. Other reports: "severe impairment of intellectual performance" at 230 feet; "sleepiness, illusions, impaired judgment" at 165 feet; and "idea fixation, perceptual narrowing and overconfidence" in the 100- to 132-foot range. Probably the customary 130-foot limit for recreational diving in the U.S. is a good one until you know better your personal susceptibility to nitrogen narcosis and have trained yourself in coping with it. For diving much deeper than that, trimix (in which most of the nitrogen is replaced with less-narcotic helium) is probably a safer gas.

How To Tell If You Are Narced

That's tough because your judgment, the faculty you depend on to tell you if you are affected, is the first to be attacked by the narcosis. Returning to the analogy to alcohol, it's like asking how you can tell if your driving is affected after you've had a few drinks. In both cases, you should probably just assume it.

Some divers experienced with deep water like Gilliam have developed their own versions of roadside sobriety tests. Not foolproof, but better than nothing:

  • Every few minutes, check your depth and tank pressure, and write them on your slate. Check your buddy's depth and pressure and write them on your slate. Your buddy does the same on his slate. Now each of you has to point to your own and your buddy's numbers on both slates, and the slates have to agree. This test automatically compares both divers, which can be valuable if one diver is narced and the other is not.
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  • Every few minutes, hold up a number of fingers to your buddy (say, three fingers). He has to respond with the same number plus one (four fingers).
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These "roadside" tests aren't foolproof because many of the effects of mild to moderate nitrogen narcosis can be overcome, or at least masked, if you try hard enough. Your mind can be impaired, but if you devote all your diminished resources to one job, you can do it well. This can drive researchers crazy. In one case, subjects in a chamber at a "depth" where they should have been narced performed the tests better than at the surface. In other studies, narced divers have often been able to attain good accuracy at the expense of speed, or vice versa. This means you might be able to perform the match-slates test or the count-fingers test and still be narced. So watch your responses (and your buddy's) for both accuracy and speed.

You are like the drunk driver who, by fierce concentration, is able to keep his car between the white lines. Obviously, the greater danger for both of you is the unexpected, not the routine. It's the entanglement or a regulator free-flow, the sharp curve and the tree. So leave the nitrogen party early and dive carefully. Mom's right: There is such a thing as too much fun.

How To Beat Narcosis

Start by assuming you will be narced if you go deeper than 100 feet. You can't prevent nitrogen narcosis entirely, but you can minimize it and compensate for it.

  • Be clean and sober. Avoid over-the-counter meds like Sudafed and Dramamine if you can, because they may potentiate the narcotic effect. It goes without saying that you shouldn't drink and dive, but even a hangover from last night's drinking can make narcosis worse and reduce your ability to cope with it.
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  • Be rested and confident. Fatigue and anxiety may help trigger narcosis, and certainly are stresses that diminish your ability to solve problems.
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  • Use a high-quality regulator in good condition. High breathing resistance elevates your carbon dioxide level, which potentiates narcosis.
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  • Avoid task-loading. Don't try to do too much, because that causes stress and anxiety. Your first excursion below 100 feet is not the time to figure out a new camera housing, for example, because it will divert your diminished mental capacity from what's most important—diving safely. Keep it simple, stupid, because stupid you will be.
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  • Be overtrained. Most of us never practice the basic safety skills like air sharing and weight dumping because they seem so simple. But under the influence of narcosis, the simplest tasks become more difficult. If you have to think about it, you may not be able to do it, and your repertoire of skills may be stripped down to those made automatic by frequent rehearsal.
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  • Approach limits gradually. Don't go to 130 feet until you've been to 110 a few times, seen how you react and become comfortable with the depth. And descend slowly, as there is some evidence that rapid compression makes narcosis more severe.
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  • Use a slate. Don't depend on remembering the dive plan or the camera controls; write them down. That frees up mental RAM for coping with the dive itself. And a slate is useful for narcosis tests like writing down depth and tank pressure.
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  • Schedule gauge checks and buddy checks. Don't check your tank pressure only when you think of it. Plan to check at stated intervals, say every two minutes. Likewise, plan to look for your buddy and make eye contact on a schedule, like every minute. Discipline helps keep you focused, and if either of you consistently misses appointments, suspect narcosis.
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  • Be positive and motivated. Experiments have shown that divers who want to conquer narcosis and believe they can, actually do. At recreational depths, narcosis is fairly mild and controllable. The key is to be optimistic but prepared, confident but prudent.
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Aliens of the Deep: Deep-sea Sharks Are the Hidden Stars of Shark Week

I have spent much of the last 30 years underwater. I’ve explored the deep on thousands of scuba dives and numerous submersible trips to 18,000 feet [5,500 meters] below the surface. Yet during all these journeys, I have only rarely encountered some of the ocean’s biggest mysteries: deep-sea sharks.

Twenty-seven years ago, a small cable outfit broadcast a week of television all about sharks. In the many years since, while the Discovery Channel’s Shark Week has not shied away from controversial shows depicting attacks, it has also brought sharks into the public consciousness and educated the public about their importance to our oceans.

The casual fan of Shark Week can probably name the big three: the great white, tiger and bull sharks. They are the DiCaprio, Clooney and Pitt of the shark world. As important as these are, they are just three members of the shark family, which includes over 400 species. To me, the most amazing sharks are the little-known species that lurk in the deep sea.

Over the years, we’ve learned quite a bit about shallow-water sharks because they’re in the reef — in the dive zone where we can see them. Deep-sea sharks seem almost alien to us because they’re so deep in the ocean that it’s hard to get there and observe them. The pressure is extremely high, temperatures are extremely low and only in the last several decades have we had underwater vehicles, robots and submarines that can get down into these depths.

Here are some of the few things that we do know about them:

Goblin shark: One of the strangest-looking fish in the ocean, very few specimens have been caught and studied. It was first found in Japan, but is probably widely distributed in the deep sea. Frill shark: This true example of a living fossil is typically never found in shallow water; when it is, it’s usually in distress. Eel-like in shape, and up to 6 feet [1.8 meters] long, they can distend their mouths open and eat things that are more than half their body length.

Bluntnose sixgill shark: This shark can grow up to 16 feet [5 meters] long and 1,300 pounds and can attack like a great white shark, but with a stronger bite. Though primarily a deep-sea species, some make trips to the shallows at night, allowing for the unsuspecting night-diver to chance upon them.

Greenland shark: This is one of the largest sharks in the world, reaching up to 24 feet [7.3 meters] in length. It is probably the most northern-ranging of shark species, living mainly in deep, very cold water of the high North Atlantic and Arctic Oceans The species has been found at a depth of more than 7,000 feet [2,130 meters], yet stomachs of some specimens have contained polar bear, pieces of horse and even an entire reindeer. Whether those animals were eaten at the surface or scavenged from the bottom is not known.

Megamouth shark: This species was only first discovered in the ocean in 1976; with only about 50 sightings worldwide, it remains one of the poorly known sharks. This species filters plankton from the water, a feeding mode that it may have evolved independently from the two other known filter-feeding sharks, the basking shark and whale shark.

We know that all sharks are important to human well-being. Some evidence of this is well-proven; other potential benefits remain unstudied. We know that sharks keep the food web in check and are a vital part of healthy fisheries. They boost local economies through ecotourism, have the potential to cure a variety of diseases, are a vital part of the carbon cycle and inspire smart design in items ranging from swimsuits to mechanisms that harness wave energy.

Studying deep-sea sharks in particular could bring us valuable knowledge. Science is on the cusp of understanding the power of genomes in nature. These deep-sea sharks, along with other specialized deep-sea organisms, including bacteria and worms that live on the seafloor, contain an infinite encyclopedia of genetic knowledge that has allowed them to survive in the most extreme environment on our planet. Their evolutionary secrets could open doors to understanding our own existence and survival on Earth.

One thing we do know is that sharks in all parts of the ocean are under pressure from human activity. Overfishing and unsustainable practices, like shark finning, account for the death of an estimated 100 million sharks per year. Even these deep-water dwellers face these threats.

The oceans’ depths are no doubt hiding many more secrets that human beings have yet to lay eyes upon. The Megalodon — an extinct shark the size of a school bus — may be gone, but there is still a whole range of deep-sea sharks in our oceans waiting to be studied, with probably others waiting to be discovered. As long as we can give them the same attention and protection we give to great white, tiger and bull sharks, I know there is much we can learn from them about how our oceans work.

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Ultrasound Ocean Noises Pose Risk to Marine Life

Noise pollution has now become one of the common themes of human-generated impacts on the ocean. Shipping noise, military sonar, and seismic airgun surveys are increasingly becoming part of the public discussion in marine conservation. These noises are easy for us to understand; they are loud, ubiquitous, and they are all in the range of human hearing. We can all imagine what it must be like having an expressway of supertankers and cargo vessels plying the shipping lanes over our heads, or being subjected to ear-piercing tactical sonar signals.

But there is a flood of noises creeping into the ocean that, while we humans can’t hear them, may prove equally as insidious as the loud noises that we can hear. Dolphins, porpoises, beaked whales, and sperm whales – the “toothed whales”–use high frequency bio-sonar, so their sound frequency sensitivities reach well above the frequencies that we humans can hear.

Some of their fish prey can also hear these higher frequencies as an adaptive measure against predation. And while we don’t yet have evidence of seals using bio-sonar, we do know that many seals also hear sounds well above the highest frequencies that humans can hear.

While marine technologists don’t seem to be giving it a lot of thought, our sonar technologies are increasingly crowding out these higher frequency bands with underwater acoustical beacons, echo sounders, and underwater communication systems. The spectrogram below (and the ones accompanying the sound examples) is a method of visualizing sound with time on the horizontal “x” axis, and frequency on the vertical “y” axis. The lower frequencies are closer to the bottom.

This particular spectrogram from NEPTUNE Canada displays a year of sound near the sea floor in the ocean off of Vancouver Island.

In the figure there is a thick cyan line just between the 30 kHz and 40 kHz index lines going across the entire year. This is from an upward-looking echo-sounder used to measure ocean currents. This signal is way above our hearing range, so we call it “ultrasound.” But this sound is right in the middle of the hearing range of orcas, dolphins, and porpoises.

The echo-sounder signal is not complex, but it is persistent. Communication signals on the other hand are necessarily complex and can sound quite obnoxious (these examples are in the human auditory range).

Increasingly, these types of sounds are being used to control equipment, report on sensor conditions, and even monitor the movement of tagged sharks. Given that some of these high frequency signals are designed to broadcast up to 10 kilometers (6 miles), the increasing density of these signals in the ocean may be cropping up as a problem for the animals that can hear them.

Yet relief may be within reach. While the ocean is getting louder with the sounds of mechanization and technology, it was not necessarily quieter before the industrialization of shipping. The ocean was probably a pretty noisy place before the 20th century due to biological noise. Since the industrialization of whaling and fishing millions of whales and perhaps 90% of all fish have been pulled out of the sea–along with all of their noises.

The difference, of course, is that these “legacy noises” were natural. This may or may not be significant with the broad-band mechanical noises of ships or the loud pulsing of seismic surveys, but it is possible that technical communication signals could be crafted to sound more like animal communication sounds, and less like the antagonistic sounds currently in use.

We know that some of these community animals can be quite loud, and that for the last 30 million years they have been swimming around in large groups. If technical communication signals sounded more like animal communication signals they may fit right in!

Subsea telemetry acoustic transceivers used in offshore oil operations  Illustration: NautronixSubsea telemetry acoustic transceivers used in offshore oil operations (Illustration: Nautronix)

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Michael Stocker on Alaska BowpickerMichael Stocker on Alaska Bowpicker

Michael is the founding director of Ocean Conservation Research, a scientific research and policy development organization focused on understanding the impacts of, and finding technical and policy solutions to the growing problem of human-generated ocean noise pollution. He is a technical generalist conversant in physics, acoustics, biology, electronics, and cultural history, with a gift for conveying complex scientific and technical issues in clear, understandable terms.

He has written and spoken about marine bio-acoustics since 1992, presenting in national and regional hearings, national and international television, radio and news publications, and in museums, schools and universities.

His book titled “Hear Where We Are: Sound, Ecology, and Sense of Place” is published by Springer. The book reveals how humans and other animals use sound and sound perception to establish their placement in their environment, and communicate that placement to others.

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Tips for Wearing Less Weight While Diving

The ballast weight you carry doesn't change during a dive, but it's often the biggest problem for divers who struggle with perfecting neutral buoyancy. Many divers are overweighted for the type of diving they do, carrying more lead than they need. That makes buoyancy control more difficult because every extra pound of lead has to be balanced with an extra pound of buoyancy. 

But because the air in your BC expands and contracts with depth changes, you have to be constantly adding or subtracting air from your BC. So extra lead means extra thrust up or down when you change depth, and requires extra fiddling with your BC valve controls. Sometimes it means nearly constant fiddling.

Here are our tips for taking off that extra weight.

Just do it. Take off two pounds before your next dive. Can't get below the surface? Before you reach for the lead again, make sure you really need it. Getting below the surface, especially on the first dive of the day, can be surprisingly difficult and can trick you into carrying more lead than you really need. 

Be patient. The plush lining of a dry wetsuit can trap a surprising amount of air, and therefore buoyancy, in its fibers, and it takes a minute or so to get fully wet.

Reach up. Hold the inflator hose over your head and stretch it upward a little so its attachment point to your BC is highest. At the same time, says Linda Van Velson, a PADI course director, "dip your right shoulder and squeeze the BC against your chest with your right arm." This maneuver encourages the last few bubbles to find the exit.

Rock backward a little. Many BCs trap a bubble of air just behind your head. Rocking backward as if you are in a La-Z-Boy recliner moves the exhaust hose over the bubble and lets it escape.

Relax. Many of us move our hands and feet more than we realize, especially at the beginning of the dive. To counteract that, hold your right arm still at your side (your left is holding up your exhaust hose), extend your legs and point your fins straight down so they have the least resistance to sinking.

Exhale. Another tendency is to hold your breath, and a lungful of air adds as much as 10 pounds of buoyancy. Exhale and hold it until you start sinking, then take shallow inhales until you get below five feet.

Force it. Another option is to use your body weight to generate some downward momentum by lifting part of it out of the water, then letting it fall back. Lying on your face, jackknife your upper body downward, then lift one leg, then another, out of the water. The weight of your legs will drive you downward, and once your fins are in the water you can kick down.

Use the line. If the dive boat is tied off at a mooring, use the line to help pull yourself down. This trick also works for divers who need to go down slowly to equalize. 

Get a little help from your friends. Ask your buddy to gently tug your fin and pull you down for the first few feet of your descent. Usually, by the time you're in 10 to 15 feet of water, you should sink without help.

What's the ideal amount of weight? Use our Buoyancy Calculator to determine what's right for you.

Read our Tips on Neutral Buoyancy for more secrets on achieving a the feeling of weightlessness underwater.

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Tips for Avoiding Dive Mask Leaks

A leaky mask has got to be the most annoying thing a diver has to  deal with when trying to enjoy a dive (with a fogged-up mask coming in a close second). So any extra effort you can invest in the dive store fitting a new mask to your face is definitely time well spent. 

However, the standard dry-fit procedure of centering the mask on your face, making sure all skirt edges are in contact with your skin, then inhaling gently —without the strap attached — to see whether you can get an airtight seal, won’t necessarily guarantee that you’re going to have a leak-proof dive. While some lucky divers are able to put their masks on and hit the water and never touch their mask for the entire dive, for most of us, getting our mask fully sealed takes a little finesse. We've got some tips to avoid those annoying leaks:

• After giant-striding into the water and popping to the surface, take a moment to remove your mask, give your head a good double-dunking, and hand-squeegee your hair back and away from your face. Then, position the mask on your face before stretching the strap over your head. If you’re wearing a hood, you can forgo the hair step as long as no renegade strands are sticking out. But run a finger around the edge of the hood opening to make sure the mask skirt is against your skin and not overlapping the neoprene.

• Double-check to make sure the mask is properly centered on your face. If it’s not, you probably will break the seal once you start diving. Also, double-check the position of the strap on the back of your head. If it it's too high, it tends to lift the bottom of the skirt; if too low, it affects the top of the skirt. If it's too tight, it can distort the shape of the skirt — that can break the seal too. 

• Just before descending, push the mask lens inward, forcing some air out and creating a good air pressure seal. Now you’re ready for your descent. Once under water, if the seal is sound, water pressure should take over and you should be good to go. At some point, you’ll probably want to nose-blow a little air back in to avoid getting mask squeeze as you go deeper.

By following these steps, hopefully you’ll be able to pull off a dive without having to contend with water constantly seeping — or gushing — into the mask. If not, you might want to consider investing in a purge mask. 

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The Secret to Neutral Buoyancy Underwater

There's no denying that peak performance buoyancy control separates the dive paddlers from the pros. When all the big talk is over and the water closes over your head, there is nothing that pulls the whole scuba diving thing together like perfect buoyancy control. 

The secret is pinpoint buoyancy control, and it all begins with fine-tuning your weighting — that's how much lead you thread on your belt or put into your pouches. If you are carrying just the right amount of weight, you will have the smallest amount of BC inflation. That means less drag and more efficient finning. Less BC inflation also means less buoyancy shift with depth, so you'll make fewer adjustments. There are many tricks, but pinpoint buoyancy control is the fundamental skill. Precise control of your buoyancy is what enables you to hover completely motionless and fin through the water, at any depth, without using your hands at all.

It sounds easy, so why isn't it?

In fact, pinpoint buoyancy control requires getting more than one thing right. 

The factors that affect your buoyancy besides ballast weight are BC inflation, your trim, exposure suit, depth and breath control. Your ballast weight and your trim are the only two factors that, once you've selected them, stay put. All the others are variables, changing during the dive along with time or depth or both. Some you can control, some you can't. 

Here is our advice for getting perfect neutral buoyancy so you can enjoy your time underwater without fiddling too much with your BC inflator hose.

Take a course. PADI offers a course in buoyancy and weighting called "Peak Performance Buoyancy." The course teaches precise buoyancy control, streamlining, weight and trim adjustment, equipment configuration options and relaxation techniques. 

Pre-dive preparation. Real buoyancy control begins, as does any dive, with pre-dive preparation. As you pack and check your equipment, double-check to make sure nothing has changed that could affect initial weighting. New wetsuit? Major factor. Nice, springy wetsuits need more weight than old rancid flatties. A fresh suit has more inherent buoyancy at first because diving, especially deep diving, simply bursts its bubbles. New BC? Unlikely to have a major effect at this point, but it will in the water. New weight belt? Maybe a nifty new shot belt? Take a moment to make sure the new compares well to the old. Stick 'em on a bathroom scale; often there is variation between claimed and actual weight. New cylinder? Another biggie. Some cylinders are negatively buoyant when full and simply less negative when empty; others sink first and float later.

Do a buoyancy check. Here's how to make a proper buoyancy check: With your lungs half-full, you should float at eye level with no air in your BC. But the fact that your average cylinder loses about 5 pounds as it empties gets you thinking about the buoyancy change in a tank and is a good reminder that it's best to do a buoyancy check with a nearly empty cylinder before you dive. This is obviously a bit of a pain, so add about 5 pounds to your weight if you have done your buoyancy check with a full one. You can always take a moment and recheck buoyancy after a dive, just before you get out of the water. See our Buoyancy Calculator  for more tips on being properly weighted. If you you're overweighted because you struggle with descents, read How To Take Off Weights for tips on getting down without adding weights.

During the dive. Now for the dive itself. Understand why feet-first descents have many advantages: One is that it's easiest to completely empty your BCD in this position. Double-check that the point where the deflator hose attaches to the bladder is really the closest point to the surface as you prepare to descend. It's often helpful to dip your opposite shoulder. Exhale, and if you're properly weighted, you should sink slowly. Keep your hand on the BC inflator and get ready to add controlled bursts of air to adjust your descent rate. You'll add more as the descent continues. If you're making a deep dive for the first time, it can be a bit of a surprise to see just how much air you have to add as you continue. During the dive, enjoy the fruits of your labor. Concentrate on what happens as you breathe. If you see something interesting below you, exhale and drift down for a look. Inhale and you'll level off and start to rise. Don't vary your breathing habits too much, though; breathing slowly deeply and continuously is of primary importance. 

During the ascent. Keep the point about BC positioning in mind while making gradual ascents too. It's easy to trap some air in an unfamiliar BC, which will continue to expand as you ascend. On deeper dives, and given neutral buoyancy, you should only have to start swimming up a little before expanding air takes over. Make sure you're ready to vent this off as needed.

Make the safety stop count. The goal is to be neutral while doing your end-of-dive safety stop, so that's when you can really fine-tune your buoyancy. As you near the surface, stop at 15 feet. After three minutes, kick slowly for the surface. If you have done everything right, there should be no air in your BCD as you break the surface. You should also now be floating at eye level, rising a little as you inhale and sinking slowly as you exhale. If this is not the case, make appropriate adjustments before your next dive.

Log it. After each dive, write down what exposure suit you wore, what equipment you used, how much lead you carried, how much your body weighs and whether you seemed too heavy or light at your safety stop.

SALT WATER VS. FRESH WATER WEIGHTING

If most of your diving is done in freshwater springs or lakes, then ballast calculations should be done in freshwater. If you dive mostly in the ocean, then do the calculations in saltwater. If you switch back and forth, you’ll need to adjust your ballast needs as you go. Be prepared to add anywhere from 4 to 7 pounds going from fresh to saltwater.

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Young loggerhead turtles not going with the flow

uvenile loggerhead turtles swim into oncoming ocean currents, instead of passively drifting with them, according to a study published August 6, 2014 in the open-access journal PLOS ONE by Donald Kobayashi from National Oceanic and Atmospheric Administration and colleagues.

After loggerhead turtle hatchlings leave nesting beaches, they live in the ocean for 7-12 years before migrating to coastal habitats. Juvenile loggerhead turtles have good swimming abilities, but scientists aren't sure if they passively drift in ocean currents or actively swim. Combining turtle movement data with ocean circulation models aids scientists in understanding how juvenile turtles orient themselves in response to a current flow. In this study, scientists compared the daily movement over the course of 13 to 350 days of ~40 juvenile loggerhead turtles tracked by satellite with oceanic circulation data from various sources off New Caledonia.

The authors found that the turtles were swimming against the prevailing current in a statistically significant pattern at a rate of 30 cm/sec, which indicates an ability to detect the current flow and orient themselves to swim into the current flow direction. The authors suggest that the turtles likely use multiple sensory cues that enable them to orient and offset displacement due to wind and ocean currents. Additional factors could be taken into consideration for future studies to provide more information about why this swimming pattern exists, to further explore turtle ecology in ocean currents.

"This study provides evidence that these oceanic stages of loggerhead sea turtles studied with satellite tags do not necessarily get passively transported with ocean currents and, further, provides compelling evidence that these turtles are able to resist such transport using some mechanism not yet fully understood. They are apparently able to detect the direction of current flow and swim against the prevailing current," Dr. Kobayashi added.

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Family Finds 300-Year-Old Sunken Treasure

A Florida family scavenging for sunken treasure on a shipwreck has found the missing piece of a 300-year-old gold filigree necklace sacred to Spanish priests, officials said on Tuesday.


Eric Schmitt, a professional salvager, was scavenging with his parents when he found the crumpled, square-shaped ornament on a leisure trip to hunt for artifacts in the wreckage of a convoy of 11 ships that sank in 1715 during a hurricane off central Florida's east coast.


After the discovery last month, a team of Spanish historians realized the piece fit together with another artifact recovered 25 years ago. It formed an accessory called a pyx, worn on a chain around a high priest's neck to carry the communion host. The dollar value is uncertain.


"It's priceless, unique, one of a kind," said Brent Brisben, operations manager for Queens Jewels, which owns rights to the wreckage, located in 15-foot (4.5-meter) deep Atlantic Ocean waters.


Schmitt, who lives near Orlando, last year discovered about $300,000 worth of gold coins and chains from the same wreckage, Brisben said. Schmitt's parents have hunted for sunken treasure as a hobby for a decade.


By law, the treasure will be placed into the custody of the U.S. District Court in South Florida, Brisben said. The state of Florida may take possession of up to 20 percent of the find. The rest will be split evenly between Brisben's company and the Schmitt family.

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Octopus mom protects her eggs for an astonishing 4-1/2 years

A deep-sea octopus (Graneledone boreopacifica) is shown on a ledge near the bottom of Monterey Canyon, California, about 1,400 meters (4,600 feet) below the ocean surface.

 

WASHINGTON (Reuters) - If someone were to create an award for "mother of the year" in the animal kingdom, a remarkably dedicated eight-limbed mom from the dark and frigid depths of the Pacific Ocean might be a strong contender.

Scientists on Wednesday described how the female of an octopus species that dwells almost a mile below the sea surface spends about 4-1/2 years brooding her eggs, protecting them vigilantly until they hatch while forgoing any food for herself.

It is the longest known egg-brooding period for any animal, they wrote in the scientific journal PLOS ONE.

The scientists used a remote-controlled submarine to monitor the deep-sea species, called Graneledone boreopacifica, off the coast of central California.

They tracked one female, recognizable by its distinctive scars, that clung to a vertical rock face near the floor of a canyon about 4,600 feet (1,400 meters) under the surface, keeping the roughly 160 translucent eggs free of debris and silt and chasing off predators.

This mother octopus never left the oblong-shaped eggs - which during the brooding period grew from about the size of a blueberry to the size of a grape - and was never seen eating anything. The octopus progressively lost weight and its skin became pale and loose. The researchers monitored the octopus during 18 dives over 53 months from May 2007 to September 2011.

Bruce Robison, a deep sea ecologist at the Monterey Bay Aquarium Research Institute in Moss Landing, California, said this species exhibits an extremely powerful maternal instinct.

"It's extraordinary. It's amazing. We're still astonished ourselves by what we saw," Robison said.

Most octopus females lay a single set of eggs in a lifetime and die shortly after their offspring hatch. The newborn of this species are no helpless babies. The long brooding period enables the hatchlings to come out of their eggs uniquely capable of survival, emerging as fully developed miniature adults able to capture small prey.

At this tremendous depth, there is no sunlight - the only light comes from bioluminescent sea creatures - and it is very cold - 37 degrees Fahrenheit (3 degrees Celsius). "It may seem nasty to us, but it's home to them," Robison said.

During the brooding period, the mother octopus seemed to focus exclusively on the welfare of the eggs.

"She was protecting her eggs from predators, and they are abundant. There are fish and crabs and all sorts of critters that would love to get in there and eat those eggs. So she was pushing them away when they approached her," Robison said.

"She was also keeping the eggs free from sediment and was ventilating them by pushing water across them for oxygen exchange. She was taking care of them," Robison added.

This species measures about 16 inches (40 cm) long and is a pale purple color with a mottled skin texture. It eats crabs, shrimp, snails - "pretty near anything they can catch," Robison said.

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World Trade Center Ship Traced to Colonial-Era Philadelphia

 

 

Four years ago this month, archaeologists monitoring the excavation of the former World Trade Center site uncovered a ghostly surprise: the bones of an ancient sailing ship. Tree-ring scientists at Columbia University’s Lamont-Doherty Earth Observatory were among those asked to analyze its remains for clues about its age and origins. In a study now out in the journal Tree Ring Research, the scientists say that an old growth forest in the Philadelphia area supplied the white oak used in the ship’s frame, and that the trees were probably cut in 1773 or so — a few years before the bloody war that established America’s independence from Britain.

The entire ship was scanned before its removal to create a precise record of where each of its pieces were originally found. (Corinthian Data Capture LLC)

 

Key to the analysis was wood sampled from Philadelphia’s Independence Hall two decades earlier by Lamont tree-ring scientist Ed Cook. It turns out that growth rings still visible in the building’s timbers matched those from the World Trade Center ship, suggesting that the wood used in both structures came from the same region. As trees grow, they record the climate in which they lived, putting on tighter rings in dry years and wider rings in wet years. In the process, a record of the region’s climate is created, allowing scientists to see how Philadelphia’s climate differed hundreds of years ago from say, New York’s Hudson Valley. The climate fingerprint also serves as a kind of birth certificate, telling scientists where pieces of wood originated.

 

The ship itself has been tentatively identified as a Hudson River Sloop, designed by the Dutch to carry passengers and cargo over shallow, rocky water. It was likely built in Philadelphia, a center for ship-building in Colonial times. After 20 to 30 years of service, it is thought to have sailed to its final resting place in lower Manhattan, a block west of Greenwich Street. As trade in New York harbor and the young country flourished, Manhattan’s western shoreline inched westward until the ship was eventually buried by trash and other landfill. By 1818, the ship would have vanished from view completely until the terrorist attacks on Sept. 11, 2001 set in motion the events leading to the World Trade Center’s excavation and rebirth. 

Some of the trash found amid the ship’s remnants included this leather shoe identified by experts at Colonial Williamsburg as made sometime from 1790-1810.

 

All images courtesy of Lower Manhattan Development Corporation unless otherwise stated. 

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X Still Marks Sunken Spot, and Gold Awaits

But the quest to salvage the S.S. Central America — which went down in 1857 in a hurricane off South Carolina carrying 425 souls, as well as thousands of coins, bars and nuggets of California gold — has produced a quarter-century of broken dreams and legal nightmares.

The bones of the side-wheeler were discovered in 1988, nearly a mile and a half down. The finder hauled up glittering coins and boasted of treasure worth $1 billion.

But paralysis ensued as waves of insurers and angry investors filed rival claims. Recovery of the shipwreck languished as courtrooms echoed with charges of fraud. In 2012, the finder became a fugitive.

Now, with the legal obstacles cleared, a private company working with a court-appointed receiver has become the first to revisit the shipwreck in two decades. It is, the team was delighted to find, still heavy with treasure.

On April 15, the company, Odyssey Marine Exploration, lowered a robot into the depths of the Atlantic Ocean and hauled up five gold bars weighing 66 pounds — worth about $1.2 million as metal and more as artifacts. That step, the company says, opened a new chapter in the saga of the Central America that will include raising the rest of the gold and exploring the deteriorating shipwreck. “We want to show that it can be done right,” Gregory P. Stemm, Odyssey’s chief executive, said in an interview. “It’s a great opportunity.”

When it sank, the Central America was steaming toward New York with a cargo meant to strengthen the city’s banks. The 280-foot vessel was carrying so much gold — commercial and personal riches from the California fields estimated at three tons, as well as a rumored secret federal shipment of 15 tons — that its loss contributed to the Panic of 1857, considered the first global financial crisis.

From the start, the locus of the recovery drama has been Columbus, Ohio — a landlocked city not known for treasure hunters. It is, however, home to the Battelle Memorial Institute, a private contractor specializing in science and technology.

Thirty years ago, Thomas G. Thompson, a plucky Ohio native who was a young engineer at Battelle, began wooing investors with dreams of finding the Central America. Soon, the Columbus America Discovery Group was formed to finance the hunt, including a robot with lights, cameras, arms and claws.

The team hit pay dirt in September 1988: Piles of gold coins and ingots lay scattered across the ship’s rotting timbers, and overnight, the investors became millionaires — in theory, at least.

In all, the team lifted up about two tons of gold. If sold today as pure metal, it would fetch $76 million.

But as news of the sensational find went public, the group’s investors were not the only ones paying attention. Claims to the fortune came from an order of Catholic monks, a Texas oil millionaire, and Columbia University, where an oceanographer had provided Mr. Thompson with sonar imagery of what turned out to be the shipwreck. And scores of insurance companies insisted that the treasure was rightfully theirs because of claims paid more than a century earlier.

Thus began a legal battle that kept the gold locked away. The disputes crippled Mr. Thompson’s ability to raise new funds, and treasure. It was not until about 2000, when insurers were awarded $5 million in gold, that his hands were untied. He sold much of the remaining treasure that his team had recovered, making a reported $52 million.

But his 251 investors got nothing. In 2005, some of them sued. John G. McCoy, a Columbus mogul who had invested $219,000, told Forbes in 2006, “I think he was dishonest from the word go.” Mr. Thompson avoided courtrooms, always speaking through intermediaries.

One dispute centered on 500 coins that had seemingly vanished. In a 2012 filing, Mr. Thompson said they had gone into a trust in Belize, and in August of that year — when he failed to show up for a hearing — a federal judge ordered his arrest.

It turned out that Mr. Thompson and his assistant, Alison Antekeier, for years had lived in Vero Beach, Fla., in a mansion set on four acres. By the time federal marshals went there to arrest Mr. Thompson, they had fled.

The Columbus Dispatch, whose parent company had invested $1 million in the gold hunt, reported that the couple had left behind empty coin boxes, currency wrappers marked $10,000 (used to band $100 bills in stacks of 100), a bank statement listing a balance of more than $1 million, and a book on assuming a new identity.

Federal marshals had billboards put up in Ohio and Florida seeking information about Mr. Thompson and Ms. Antekeier.

 

       

N.C.

S.C.

pproximate location of wreck

Mr. Thompson’s last known lawyer, Shawn J. Organ, in Columbus, no longer represents the gold hunter. “He’s incommunicado,” said Liberty P. Casey, Mr. Organ’s office manager. “We haven’t seen him or been able to track him down.”

Last May, the marshals auctioned off Mr. Thompson’s 180-foot ship, the Arctic Discoverer. Its safe was empty.

An important part of the legal drama was resolved that month, when Judge Patrick E. Sheeran of the Court of Common Pleas in Franklin County, Ohio, named as receiver Ira O. Kane, a Columbus lawyer and businessman whose task was to recover as much gold as possible for the benefit of creditors and duped investors.

This March, Mr. Kane picked Odyssey — based in Tampa, Fla., and publicly traded — to resume the hunt.

The stakes? Mr. Thompson recovered 532 gold bars and some 7,500 gold coins whose total face value, in 1857 dollars, was $1,126,000. Experts hired by Mr. Kane estimated the likely face value of the remaining gold at $760,000, but put the range at $343,000 to $1,373,000. In other words, more than half the treasure could still be sitting at the bottom of the sea, at least in theory.

Mark D. Gordon, Odyssey’s president, told investors in March that the remaining treasure, thought to be mostly gold coins, would fetch at least $85 million if sold for its value to collectors. On eBay, $20 coins from the original haul sell for up to $26,500.

Not included in the receiver’s estimate was a cargo long rumored to be aboard the wreck: 15 tons of Army bullion. A best-selling book about the discovery, “Ship of Gold in the Deep Blue Sea” by Gary Kinder, published in 1998, called it a secret shipment meant to shore up the faltering Northern industrial economy, and said the Army had recently declassified its existence.

In an interview, Mr. Stemm of Odyssey said the reconnaissance dive and retrieval of the five gold bars on April 15, as well as two gold coins, was important for demonstrating that, contrary to rumors that the site had been looted, the deteriorating shipwreck was still tantalizingly rich with treasures.

“It’s clear they didn’t do a complete recovery,” Mr. Stemm said of the original team. He added that the dive “confirms that the site has remained untouched” since the last retrievals more than two decades ago.

Helping direct the April 15 operation was Bob Evans, the chief scientist and historian of the Recovery Limited Partnership, one of Mr. Thompson’s insolvent companies and the legal owner of the shipwreck. “I’m elated,” Mr. Evans said in an interview. “I’m fulfilling my dream.”

On April 23, the new recovery ship, Odyssey Explorer, sailed from Charleston to renew the hunt. As a prelude to recovering the remaining gold, Odyssey is surveying the wreckage and will perform an archaeological excavation of the remaining artifacts. The company also plans to collaborate with a scientist from the Woods Hole Oceanographic Institution to study deep-sea life colonizing the site, and to continue science experiments initiated by Mr. Thompson’s team.

Odyssey will absorb the expedition costs if little treasure is recovered. If the take is substantial, the company will get 80 percent until it recoups its costs. After that, Odyssey’s share will drop to 45 percent.

Judge Sheeran, like the surviving investors, is eager to see what develops.

The new plan, he wrote last year, bodes well for “the rebirth” of the enterprise and a renewed sense of awe as “more treasure, both historical and monetary, makes its way from the depths of the seas.”

As for Mr. Thompson, it seems likely that he, too — wherever he is — is giving serious attention to what emerges next from his ship of gold 

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U/W Bike Race

eventsiconJoin us on July 4th for this annual event benefitting the Children's Mile of Hope.

Lionfish Tournament

eventsiconWe need your help to make Carteret County's 6th Annual "If you Can't Beat 'em, Eat 'em" Spearfishing Tournament a success! This Tournament is a joint effort between Discovery Diving and Eastern Carolina Artificial Reef Association (ECARA).

Treasure Hunt

eventsiconFood, prizes, diving, and fun! Proceeds benefit the Mile Hope Children's Cancer Fund and DAN's research in diving safety.

ECARA Event

2013Join us in support of the East Carolina Artificial Reef Association.  Click here for more info on this great event and how you can help to bring more Wrecks to the Graveyard of the Atlantic.