Does Scuba Diving NITROX Damage Blood Vessels?

There is new research suggesting in the affirm, but the study did utilize a very limited sample.

Repeat scuba dives appear to harm the endothelium, particularly when breathing the mix of gases popular with recreational divers, according to a small study.

With the low-nitrogen air mix called nitrox, endothelial function as measured by flow mediated dilation dropped significantly after each dive -- and didn't fully recover between dives, Emeline Van Craenenbroeck, MD, PhD, of Antwerp University Hospital in Antwerp, Belgium, and colleagues reported.

Endothelial repair mechanisms appeared activated as well in their study of 10 divers, presented here at the European Society of Cardiology's EuroPRevent meeting.

Based on the results of this small study, Van Craenenbroeck told MedPage Today that in his opinion the use of regular compressed air was safer for vessels.

Nitrox is popular because its lower nitrogen content allows divers to stay down longer and return to the surface faster with less decompression time needed, she explained.

But in the study, each dive with standard air reduced endothelial function by roughly 2 percentage points from around 5% flow mediated dilation at baseline (P=NS), whereas it dropped roughly 4 percentage points on the initial dive with nitrox and then, without returning to baseline, fell more than 2 percentage points on a subsequent dive two days later (both P<0.05).

"We already knew diving was bad for the endothelium," Van Craenenbroeck told MedPage Today, noting that one prior study suggested that endothelial function didn't return to baseline more than six days after just a single dive.

What effect these repeated dings to blood vessels function and repair mechanisms for frequent divers, such as military and professional divers, have on cardiovascular outcomes isn't known.

"There's no data on it," Van Craenenbroeck cautioned.

But she noted that it might be expected to lead to more atherosclerosis and coronary artery disease.

Still, divers have a choice in the gas mix they use and could attempt to protect their vessels by a preconditioning jog before going down into the water, since this method boosts oxygenation in soccer players and stimulates endothelial progenitor cells in healthy individuals, she suggested.

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Aquanauts Living on Ocean Floor Come Up for Air

Wow. Can you imagine a 16-hour deco process? Or, how about spending 9 hours a day diving. And then returning to your underwater lair.

Just another day in the life of these grad students.

From the cramped conditions inside a school-bus-sized metal tube at the bottom of the ocean, scientist Chris Finelli traded his scuba gear for a T-shirt and bare feet, ready to talk about his latest mission: monitoring sponges on Conch Reef, more than three miles off the coast of Florida.

Sponges, bottom-dwelling filter-feeders, are one of two players locked in a silent battle for supremacy that is taking place at these coral reefs and others across the globe.

As coral populations disappear — they're down by 90 percent around Florida — other species are fighting for the newly freed up ocean real estate. The two top contenders to take over are sponges and algae, and which one emerges victorious will have far-reaching consequences for the species that make their homes in coral reefs and for the humans that depend on them.

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Finelli, along with several UNCW grad students and technicians, has been living deep under water for nine days now, aboard the Aquarius, the only seafloor laboratory and habitat in the world. The National Oceanic and Atmospheric Administration (NOAA) owns the facility, which is run by UNCW.

Since 1993, the Aquarius has been stationed 63 feet below the waves, in the protected waters of the Florida Keys National Marine Sanctuary, a few miles off the coast, providing an ideal place to study ocean life and even train astronauts for space missions.

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Sea Sponges Share Human Genes

And not just a few -- apparently 70 percent.

Genetic sequencing of sea sponges from the World Heritage-listed Great Barrier Reef showed the ancient marine animal shared many of its genes with humans, including a large number typically associated with disease and cancer.

Lead researcher Bernard Degnan, of the University of Queensland, said the findings "would shed light on a whole range of different things," and could lay the foundation for breakthroughs in cancer and stem cell research.

"Sponges have what's (considered) the 'Holy Grail' of stem cells," Degnan told AFP.

Exploring the genetic function of sponge stem cells could provide "deep and important connections" to the genes that influenced human stem cell biology, he said.

"(It) might actually inform the way we think about our own stem cells and how we might be able to use them in future medical applications," he said.

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Teenage SCUBAnauts Dive Deep into Marine Science

Here's a cool article about a terrific organization.

Growing up near the beach sparked an interest in the underwater world for teenager Morgan Liston.

"I'd look at the little fish. I'd dig in the sand and look at the shells and all the little clams and stuff like that," said Liston, who recently graduated from Palm Harbor University High School.

Her childhood fascination led to her becoming certified in scuba diving, and now she's among the many teens in Scubanauts International, a volunteer youth organization that works with marine scientists.

Members scuba dive and use specialized equipment to perform underwater surveys, fish counts, coral observations and marine archeology.

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Scubanauts International was founded in 2001 by U.S. Navy Capt. David Olsen, of Palm Harbor, with Walter Jaap, a marine scientist with Florida's Fish and Wildlife Research Institute. Jaap has worked for in coral reef research more than 30 years.

Olsen, who is assigned to U.S. Central Command at MacDill Air Force Base, "wanted to be able to provide kids 12 to 18 an experience using scuba diving doing underwater sciences," Hayes said.

There are chapters St. Petersburg, Tarpon Springs, Key West and Lake Hitchcock, Mass. Parents volunteer and run each chapter, and all of the scientists who assist are volunteers.

Mary Silk, a member of Scubanauts for five years and a junior at Northeast High School, said meeting and working with the leaders in the marine science field is one of her favorite parts of the program.

"I actually do think I would be interested in pursuing a career in marine science, mostly because of this program," she said. "It's definitely opened my eyes to this wonderful career."

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You can learn more about SCUBAnauts International online at: www.scubanautsintl.org

Happy 100th, Jacques!

Born on June 11, 1910, French naval officer, explorer, ecologist, filmmaker, innovator, scientist, photographer, author and researcher Jacques-Yves Cousteau has inspired generations of ocean-lovers and made an indelible impression on our planet.

And for diligently pursuing that which he was passionate about, we are eternally grateful.

Here’s to Jacques-Yves Cousteau.

NASA Announces Dates And Crew of Next Undersea Exploration Mission

From UnderwaterTimes:

NASA will send two astronauts, a veteran undersea engineer and an experienced scientist into the ocean depths off Florida's east coast this month to test exploration concepts and learn more about working in an unforgiving, treacherous environment. The 14th expedition of NASA Extreme Environment Mission Operations, or NEEMO, begins May 10.

Canadian Space Agency astronaut and veteran spacewalker Chris Hadfield will lead the NASA team on a 14-day undersea mission aboard the Aquarius Underwater Laboratory near Key Largo. Aquarius is owned by the National Oceanic and Atmospheric Administration (NOAA) and operated by the University of North Carolina at Wilmington.

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During NEEMO 14, the ocean floor will simulate aspects of another planet's surface and a low-gravity environment. In October 2009, a team of aquanauts set the stage for NEEMO 14 by placing mockups near Aquarius of a lander, rover and small crane that simulates a robotic arm.

The NEEMO 14 crew will live aboard the underwater laboratory, venture out on simulated spacewalks, operate the crane and maneuver the vehicles much like explorers would in setting up a habitat on another planet. As the aquanauts interact with these developing technologies, they will provide information and feedback to NASA engineers.

The crew will simulate removing a mockup of the Lunar Electric Rover from the lander, retrieve small payloads from the lander and the ocean floor, and simulate the transfer of an incapacitated astronaut from the ocean floor to the deck of the craft.

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Deep Sea Oddities

From the Census of Marine Life.

Baby Octopus?

Most cephalopods (like octopus and squid) go through a paralarval stage that can look very different from the adult, although both share arms with suckers and large eyes for visual hunting. Paralarvae are generally semi-transparent, but have some photophores that allow them to change appearance very rapidly.

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Florida Cave Diving is Lucrative

That's according to the results of study recently published in a fancy schmancy academic journal.

The writers and researchers of the article — O. Ashton Morgan and William Huth of Appalachian State University in North Carolina and University of West Florida, respectively — developed a single-site travel cost model to show the economic value associated with recreational cave diving.

The end results, published recently in “Resource and Energy Economics,” amazed even the researchers. The article states that under the spring’s existing conditions, the economic impact of each diver was estimated to be approximately $146 to $167 per person, per trip. Based on the number of expected trips this translates into approximately $1,075 in annual per-person economic impact, or $575,000 a year.
However, Huth explained that since publishing the article, he has since talked to Blue Springs personnel who say the number of divers has since doubled.

“So basically we are not looking at $575,000 in annual surplus, we’re talking more like a $1 million,” Huth said. “Blue Springs could easily, beyond the jails, be the biggest incoming revenue source for Jackson County, with it bringing in about a $1 million a year.”

However, the study revealed more than just the economic impact of springs diving. It also gave insight to the cave’s potential demand among divers, if improvement to access were made.

Huth and Morgan described in their article that the cave has two potential ways to grow in consumer demand.

The first is to improve access to Twin Caves Spring and Hole in the Rock Spring, which are currently only accessible by boat.

Second, if divers were granted access to a newly discovered passage, this too would have an impact.

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Scientists Dive the Extremes for Arctic Research

And you thought your place of work got chilly in the winter.

If you want to know how polar bears are doing, it's not enough to spy on them with satellite telemetry and other technology. You have to go where they live.

You have to tap into the stories these bears carry in and on their bodies, and drop in on the tiniest of organisms beneath the places they walk, the ones that feed the shrimp-like creatures that feed the fish that feed the seals that feed the bears.

That's what scientists did for five weeks this fall aboard the U.S. Coast Guard Cutter Polar Sea as they addressed the question: How are polar bears coping with sea-ice loss due to climate change?

To get some answers, they traveled to a part of the world few get to see, and far fewer get to see from beneath the sea ice. Or would want to.

"It's definitely not for everyone," said Katrin Iken, associate professor of marine biology at the University of Alaska Fairbanks, who led the team of ice researchers from UAF.

The ice divers, layered in polypropylene, fleece and dry suits, went to work through holes cut in the ice to gather samples from biological communities associated with sea ice. Tethered to a team member above, they went as deep as 40 feet to explore the bottoms of ice ridges -- the underwater version of the pressure ridges up top -- for a look at what lives down there.

In the big picture, it's all about understanding what melting ice means to the larger food web in the Arctic.

To Iken, the underside of sea ice is a beautiful and fascinating place.

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Don't forget to check out the photos.