A Matter of Chance: Music Makes the Video

I was recently asked to give a 30-minute after-dinner talk to the 3CPR Resuscitation Panel of the American Heart Association at their annual scientific meeting in Anaheim, CA. In the audience were scientists, cardiologists, anesthesiologists, anesthetists, emergency physicians, and resuscitation technicians. It was a multimedia event with professionally managed sound and video.

Knowing that the group would be well acquainted with the role of chance in medical procedures, I chose to use a segue from medicine into the topic of extreme adventures in military and civilian diving. The focus of the talk was on how chance can turn adventures into mis-adventures.

I revealed three areas where Navy Biomedical Research is expanding the boundaries of the state of the art in military and civilian diving. One area was in deep saturation diving, another was polar ice diving, and the third was breath hold diving.

As an introduction to polar diving, I wanted to create a video travelogue of my National Science Foundation-sponsored research and teaching trips to the Arctic (Svalbard) and Antarctica (McMurdo Station and vicinity.) These projects were spearheaded by the Smithsonian Institution, and my participation was funded in part by the U.S. Navy.

To begin the preparation of the video, I assembled my most relevant photos, and those taken by various team mates, and imported them into my favorite video editing software, which happens to be Cyberlink Director.

Then I went looking for potential sound tracks for the approximately 5 minute video. Considering the topic, I thought Disney’s Frozen would have familiar themes that might be acceptable. I rejected a number of YouTube videos of music from Frozen; most were too close to the original and included vocal tracks. Finally I came across the “Let It Go Orchestral Suite” composed by the “Twin Composers,” Andrew and Jared DePolo.

It was perfect for my application. I extracted the audio track from the Suite as shown on YouTube, imported it into Director, and lined it up with the nascent video track which included all images and other video segments.

To match the music to the video, I simply cut back on the duration for each of 97 images, keeping the other 5 videos in their native length. By experimentation, I found that 3.21 seconds per image resulted in the last image fading out as the music came to a close and the end credits began to roll.

On the first run through of the new video, I couldn’t find anything to complain about; which for me is rare. So I ran it again and again, eventually creating an mp4 file which would play on a large screen and home audio system. But I couldn’t help notice that the gorgeous score would sweeten at interesting times, and serendipitously change its musical theme just as the video subject matter was changing.

How fortunate, I thought. It was then that I began to realize that “chance” had worked its way into the production effort, in an unexpected way.

First, the music seemed to my ear to be written in 4/4 time, with each measure lasting 3.2 seconds, precisely, and purely by happenstance matching the image change rate. At a resulting 0.8 seconds per beat, or 75 beats per minute, that placed the sensed tempo in the adagietto range, which seemed appropriate for the theme of the music. (Without seeing the score, I’m just guessing about the tempo and timing. But that’s how it felt to me.)

The timing coincidence was rather subtle at first, but as the finale began building at the 3:39 minute mark, the force of the down beat for each measure became more notable, and the coincidence with image changes became more remarkable. There was absolutely nothing I could do to improve it.

In some cases the technical dissection of music can be a distraction from the beauty of the music, but I’ve done it here merely to point out that sometimes you just luck out. In this case it truly was a matter of chance.

In my mind, the DePolo Orchestral Suite makes the video. Hope you enjoy the show.

To learn more about these composers and their music, follow this link. 


Nightmarish Thoughts of Being Eaten

DSCN1233aThere is a downside to situational awareness.

I discovered this fact while 868 miles north of the Arctic circle, 600 miles south of the North Pole. It took place in Ny-Ålesund, Svalbard, a part of the well-known island Spitsbergen. 

I was helping the Smithsonian Institution train divers in polar diving. My job was to teach them about scuba regulator performance in frigid water.

A fact of life in Ny-Ålesund, the most northern continuously occupied settlement, a research village, is that Polar Bears are always a threat. In fact, one came through town during our visit to Svalbard.  The Greenland sled dogs, tied down outside, were understandably, and quite noisily, upset. The bear walked right past them.


After the excitement of that nighttime polar bear prowl had begun to wane, the incident remained as a not so subtle reminder during seemingly routine activities. For you see, polar bears are emotionless killers; to them, we are prey. Tracking and eating a human gives it no more pause than us picking blackberries alongside the road. For adult polar bears, humans are simply a conveniently-sized food item, not nearly so fast and wily as their typically more available meals, seals.

Unlike the ploy of divers bumping potentially predatory sharks on the nose to dissuade them from biting, bumps on the nose don’t work with polar bears. Without a gun by your side, a walk in Svalbard is a walk on the wild side, and not in a good way.

2007-03-1505-59-59_0077I was observing and photographing boat-based diving operations from the end of a long pier jutting 375 feet (115 m) into the Kongsfjorden. Normally in March the fjord is ice covered, but the year I was there (2007) there was no ice to be seen except at the nearby glacier.

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I had been standing at the pier’s end for a while taking photographs, and soaking up the polar ambiance, when I looked back and realized that from a safety standpoint, I was vulnerable. That is when situational awareness began to kick in. 

We were in a deserted, industrial portion of the town. The old coal mining operations were shut down long ago. Other than the divers on and in the water, I was the only one around. And I was stuck out on the end of a very long pier, with no means of escape.

If an intruding and hungry bear made its appearance at the land side of the pier, I would be trapped. Although I was dressed for cold, I was not dressed for cold water. That water was, after all, ice water. Polar bears, on the other hand, are excellent swimmers in polar water. So after I’d jumped into the water, which I would have if faced with no alternative, it would have taken the bear only a few furry strokes before he would have me. While he or she would find my body parts chilled on the outside, my internals would still be pleasantly warm as they slid down its gullet.Me cropped

Being a sensible person, I called the boat drivers over and put them on alert; should a polar bear appear at the far, land-side end of the pier, they should pick me up post haste. Otherwise, there would be no way I could safely escape from my vulnerable position. No photograph is worth dying for. 


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Being nice fellows, they agreed they would keep an ear out for my shouts. They then returned to their duty of waiting for and recovering the divers.













As the boat eventually sped off with its load of thoroughly chilled divers, I realized that I had been deluding myself all along. At their distance and with the noisy interference of the boat motor, my shouts would have been inaudible. And from their low position on the water, they would have been unable to see what I was so agitated about; until it was too late.

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My return back to the safety of the diving center was a cautious one; with the full realization that I was exposed and vulnerable for the entire route. Fortunately, safety was only a third of a mile away, but that was a long 500 meters, which gave my alert mind plenty of time to focus on walking quietly, and avoiding being eaten.

Nothing focuses the mind like knowing that close by, hidden by piles of snow, could be lurking a camouflaged predator looking for lunch.




This Youtube video shows a Polar Bear searching for food in Ny-Ålesund during the brief Arctic summer.



Cold Water Regulator Blues

It’s a black art, the making of scuba regulators for use in polar extremes; or so it seems. Many have tried, and many have failed.

Once you find a good cold water regulator, you may find they are finicky, as the U.S. Navy recently discovered. In 2013 the Navy invested almost two hundred hours testing scuba regulators in frigid salt and fresh water. What has been learned is in some ways surprising.

Looking at a pony bottle that saved a diver when both his independent regulator systems free-flowed at over 100 feet under the thick Antarctic ice.

DSCN3557cropThe Navy has been issuing reports on cold water regulator trials since 1987. In 1995 the Navy toughened its testing procedures to meet more stringent diving requirements. Reports from that era are found at the following links (Sherwood, Poseidon).  (Here is a link to one of their most recent publicly accessible reports.)

The Smithsonian Institution and the Navy sent this scientist to the Arctic to help teach cold water diving, and to the  Antarctic to monitor National Science Foundation and Smithsonian Institution funded trials of regulators  for use in the under-ice environment. What those studies have revealed have been disturbing: many regulator models that claim cold water tolerance fail in the extreme environment of polar diving.

The Navy Experimental Diving Unit (NEDU) has developed testing procedures that are more rigorous than the EN 250 tests currently used by European nations. (A comparison between US Navy and EN 250 testing is found on this blog). All cold water regulators approved for U.S. military use must meet these stringent NEDU requirements.

Nevertheless, we learned this year, quite tragically, that the Navy does not know all there is to know about diving scuba in cold water.

For example, what is the definition of cold water? For years the U.S. and Canadian Navies have declared that scuba regulators are not likely to freeze in water temperatures of 38° F and above (about 3° C). (The 1987  Morson report identified cold water as 37° F [2.8° C] and below). In salt water that seems in fact to be true; in 38° F scuba regulators are very unlikely to fail. However, in fresh water 38° F may pose a risk of ice accumulation in the regulator second stage, with resultant free-flow. (Free-flow is a condition where the gas issuing from the regulator does not stop during the diver’s exhalation. Unbridled free flow can quickly deplete a diver’s gas supply.)

The regulator on the left free-flowed, the one on the right did not.

While a freshly manufactured or freshly maintained regulator may be insensitive to 38° F fresh water, a regulator that is worn or improperly maintained may be susceptible to internal ice formation and free-flow at that same water temperature. There is, in other words, some uncertainty about whether a dive under those conditions will be successful.

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An isolator valve that can be shut to prevent loss of gas from a free flowing regulator.

That uncertainty can be expressed by a regulator working well for nine under-ice dives, and then failing on the tenth. (That has happened more than once in Antarctica.)

That uncertainly also explains the U.S. Antarctic Program’s policy of requiring fully redundant first and second stage regulators, and a sliding isolator valve that a diver can use to secure his gas flow should one of the regulators free flow. There is always a chance that a regulator can free flow in cold water.

A key finding of the Navy’s recent testing is the importance of recent and proper factory-certified maintenance.  Arguably, not all maintenance is created equal, and those regulators receiving suspect maintenance should be suspected of providing unknown performance when challenged with cold water.

This finding points out a weakness of current regulator testing regimes in the U.S. and elsewhere. Typically, only new regulators are tested for tolerance to cold water. I know of no laboratory that routinely tests heavily used regulators.

Weddell seal on the Antarctic sea ice. Photo copyright Samuel Blanc. (From Wikimedia Commons).

Considering the inherent risk of diving in an overhead environment, where access to the surface could be potentially blocked by a 1400 lb (635 kg), 11 foot (3.4 m) long mammal that can hold its breath far longer than divers can, perhaps it is time to consider a change to that policy.

About to descend through a tunnel in 9-feet of ice on the Ross Ice Shelf.


A huge Weddell Seal blocks the diver’s entry hole. He looks small here, but like an iceberg, most of his mass is underwater.



Cold Water Scuba Regulator Testing — U.S. Navy vs. EN 250

Under thick ice in the Ross Sea, near McMurdo, Antarctica.

When scuba diving under 3-m thick polar ice with no easy access to the surface, the last thing you want to worry about is a failure of your scuba regulator, the system that provides air on demand from the aluminum or steel bottle on your back.

However, cold water regulators do fail occasionally by free-flowing, uncontrollably releasing massive amounts of the diver’s precious air supply. When they fail, the second stage regulators, the part held in a scuba diver’s mouth, is often found to be full of ice.

The U.S. Navy uses scuba in polar regions where water temperature is typically -2° C (28° F).  That water temperature is beyond cold; it is frigid. Accordingly, the Navy Experimental Diving Unit developed in 1995 a machine-based regulator testing protocol that most would consider extreme. However, that protocol has reliably reflected field diving experience in both Arctic and Antarctic diving regions, for example, in Ny-Ålesund, Svalbard, or under the Ross Sea ice near McMurdo Station.

There are currently both philosophical and quantitative differences between European standards and the U.S. Navy standard for cold water regulator testing. Regulators submitted for a European CE mark for cold water diving must pass the testing requirements specified in European Normative Standard EN 250 January 2000 and EN 250 Annex A1 of May 2006. In EN 250 the water temperature requirement for cold water testing ranges from 2° C to 4° C. Oftentimes, regulators that pass the EN 250 standard do not even come close to passing U.S. Navy testing.

An iced up, highly modified Sherwood SRB3600 Maximus second stage regulator

The Navy’s primary interest is in avoiding regulator free-flow under polar ice. The breathing effort, which is a focal point of the EN 250 standard, is of lesser importance. For instance, the 1991 Sherwood SRB3600 Maximus regulators long used by the U.S. Antarctic program have been highly modified and “detuned” to prevent free-flows. You cannot buy them off-the-shelf. Detuning means they are not as easy to breathe as stock regulators, but they also don’t lose control of air flow to the diver; at least not very often. Here is a photo of one that did lose control.

NEDU performs a survival test on regulators, and any that pass the harshest test are then tested for ease of breathing. The so-called “freeze-up” evaluation breathes the regulator on a breathing machine with warmed  (74 ±10°F; 23.3 ±5.6°C) and humidified air (simulating a diver’s exhaled breath) at 198 feet sea water (~6 bar) in 29 ± 1°F (-1.7 ± 0.6°C) water. Testing is at a moderately high ventilation rate of 62.5 L/min maintained for 30 minutes. (In my experience a typical dive duration for a dry-suit equipped diver in Antarctica is 30-40 min.)

To represent polar sea water, the test water is salted to a salinity of 35-40 parts per thousand.  The possible development of a “freeze up” of the regulator 2nd stage, indicated by a sustained flow of bubbles from the exhaust port, is determined visually.

In contrast, the European standards call for slightly, but critically, warmer temperatures, and do not specify a duration for testing at an elevated respiratory flow rate. I have watched regulators performing normally under EN 250 test conditions (4° C), but free-flowing in water temperatures approaching 0° C. Those tests were run entirely by a non-U.S. Navy test facility, by non-U.S. personnel, using a U.K. produced breathing machine, with all testing being conducted in a European country. The differences in testing temperatures made a remarkable difference.

Haakon Hop of the Norwegian Polar Institute in Ny-Ålesund, Svalbard.

The NEDU testing results have been validated during field testing by scientific diving professionals under Arctic and Antarctic ice. The same regulators that excel in the NEDU protocol, also excel in the field. Conversely, those that fail NEDU testing fare poorly under the polar ice. For instance, a Norwegian biologist and his team exclusively use Poseidon regulators for their studies of sea life inhabiting the bottom of Arctic ice.  (The hard hat in the photo is to protect cold skulls from jagged ice under the ice-pack.) Poseidon produces some of the few U.S. Navy approved cold-water regulators.

As is usual for a science diver in the U.S. Antarctic Program, a friend of mine had fully redundant regulators for his dive deep under Antarctic ice. He was fully prepared for one to fail. As he experienced both those regulator systems failing within seconds of each other, with massive free-flow, he might have been thinking of the words of Roberto “Bob” Palozzi spoken during an Arctic Diving Workshop run by the Smithsonian Scientific Diving program. Those words were: “It’s better to finish your dive before you finish your gas…”

In both NEDU’s and the Smithsonian’s experience, any regulator can fail under polar ice. However, those which have successfully passed U.S. Navy testing are very unlikely to do so.


A previous blog posting on the subject of Antarctic diving may also be of interest.