As nightmares go, being trapped in a small box deep underwater is probably high on many peoples’ lists. But one US professor is doing this on purpose. Joe Dituri, a former US navy diver has been living in a 55 square meter space 30 feet below the surface of the Florida Keys since 1 March, and plans to stay for 100 days. If he manages this, he will break a record for most time spent in a habitat beneath the surface of the ocean.
Dituri conducts research into the effects of hyperbaric pressure – when air pressure is greater than it would be at sea level, on the human body.
Interestingly, Dituri’s endeavour will be very different from living on a submarine. Submarines are sealed when submerged and maintained at sea level pressure
But Dituri’s underwater habitat won’t have any solid hatches or air locks between the ocean and the dry living space, as a submarine does. Think of it like when a glass of water is turned upside down and pushed into a sink full of water.
This means that the air inside his habitat is squeezed by the ocean’s weight, increasing the air pressure around him.
the two major gases involved in breathing (oxygen and carbon dioxide) are the only two that freely cross between our lungs and our blood, but as pressure increases, nitrogen in the air is forced across the delicate walls of our lungs and into our blood. At depths of ten to 30 meters, this may cause mild euphoria and positive moods. After about 30 meters below sea level and beyond, it can lead to intoxicated-like behaviour.
Fortunately, this won’t be a risk to Dituri, as he’s only at a depth of ten meters, but Dituri can expect to experience other physical changes while living in his underwater habitat.
Another challenge for Dituri will be getting enough vitamin D. The skin must receive UV exposure to make this vitamin, and this typically comes from the sun. It’s likely that Dituri will not be exposed to enough vitamin D while living in his underwater environment.
Vitamin D plays key roles in maintaining bone density, muscle function and immunity.
Besides a minimal amount of walking around a very small habitat, the only exercise Dituri will get is from swimming. As swimming is non-weight bearing, losses in bone and muscle mass are likely.
After two months below the sea, submariners still had disturbed sleep patterns. Crew also showed losses in bone and muscle mass. This reinforces how important it will be for Dituri to get enough vitamin D exposure and exercise.
Of course, the biggest question that remains is what effect long-term hyperbaric pressure will have on Dituri. What studies we do have on the effects of hyperbaric pressure have only looked at short-term exposures, this will be both a physiologically and possibly psychologically challenging feat so, although Dituri is only one person, data from his experiment will still be useful to the field.