How (and why) this man plans to live underwater for 100 days

The report was due on Christmas Day, 2012 — and so Joseph Dituri was up late on Christmas Eve.

Earlier that year, he'd retired as a U.S. Navy diver and officer and joined the team of filmmaker James Cameron's Deepsea Challenger mission to the bottom of the Mariana Trench — more than 35,000 feet under sea level.

One detail has stuck with him from reviewing the report on that trip that Christmas Eve: the finding that an organism at that depth contained a chemical that potentially could be used to treat Alzheimer's disease.

"And at that point in my life I said, 'Everything that we need is on this planet. We just need to find it,'" he told NPR's Juana Summers.

Dituri spoke to NPR from a considerably shallower depth of approximately 22 feet under the sea, in a lagoon of Key Largo, Florida. He plans to stay there for 100 days — we reached him on March 2, which was day two — which would smash the Guinness world record for continuous time spent in an underwater fixed habitat.

The record, he's told other media outlets, is only a small part of his quest. Dituri, whose website refers to himself as "Dr. Deep Sea," wants this mission to spark scientific curiosity. And he wants to harvest some data (on himself) for biomedical research.

"We gotta do something to find everything," he says.

Dituri won't be completely alone in his underwater stay. The Project Neptune 100 quest will see him receive visits from local schoolchildren on field trips, in an effort to get more kids excited about science, technology, engineering and math (STEM) pursuits.

He'll be teaching courses virtually for the University of South Florida, where he's an associate professor. And he will do "a bunch of outreach" with noted marine scientists who are coming down to conduct livestreamed conversations — among them, the oceanographer Sylvia Earle.

"I get to spend the night with Sylvia Earle down here and hang out and chitchat," he says. "How cool is that?"

His own academic background isn't exactly marine science. After 28 years in the U.S. Navy, where he became a diving special operations officer, Dituri earned a Ph.D. in biomedical engineering. His research interests are informed by his fellow veterans; he's studied treatments for PTSD, traumatic brain injury and CTE.

But his time undersea positions himself as the "guinea pig" to observe the long-term effects of a pressurized environment. He says he'll undergo a bevy of physiological exams before, after and during the 100 days. He indicated that some previous research with pressurized environments could produce positive outcomes regarding the count of circulating stem cells and the length of telomeres — the ends of chromosomes associated with cellular viability.

"We're going to look at extending life and and increasing the ability to heal myself," he says. "This is going to be great."

Regarding that pressure, even at the relatively shallow depth of 20-30 feet underwater, Dituri describes his home for 100 days as a "positive pressure habitat." Air must be pumped in to counteract the effects of water pressure.

"Basically, it has to continually bubble out," he said. "And [the noise is] an unfortunate side effect, but it's a necessity because I really like breathing."

His shelter is open to the general public at other times. It's called Jules' Undersea Lodge, and it's where the previous world record was set as well. He described it as two 8-foot diameter tubes, 13 feet long, running parallel to each other. Between them is a wet room ("unfortunately, it's very moist") where people can enter and exit the lodge.

One tube houses bunks for sleeping; the other, a small kitchen and living room area. He has a coffee machine and plenty of frozen food storage. On night one, he said he looked up an online recipe for poached salmon in the microwave.

"And it really came out wonderfully," Dituri says. "I was impressed."

Because we had to ask, he does have a toilet. He says humans have long since developed ways to flush a commode from under water. But in this case, it has to be pressurized and sent into the regular sewer lines.

"We have a macerated pump that's located down here and recycle it and push it up to the surface and joins the regular sewer line," Dituri says. "So that is a good question. You got to go somewhere."

Dituri says the living area is pretty austere, but he describes himself as a creature of habit, happy enough to eat similar things every day. But he does note that the current world record was 73 days. "Our biggest fear right now is the isolated, confined, extreme environment, because I'm at about a little over one and a half times the pressure that you're at right now," he says.

He has a team of medical doctors, trained in hyperbaric medicine, who are keeping an eye on his biometric data. He has scheduled weekly psychological interviews that he expects to increase in frequency as the days tick on. And he's taking plenty of Vitamin D supplements.

"Even though I'm having guests come down here, I'm basically in a prison cell," he says. "I mean, I can get out and swim around the outside of it, but I still have to get in and there is no sunlight."

He also notes he won't be seeing much of his family and friends for that span, including his three daughters. But he describes everyone in his corner as a little worried, and pretty supportive.

"My mother literally embraced me right before I went and — you know, typical stereotypical New York [parent] ... she goes, 'Don't do anything crazy when you're down there!'" he says. "I'm thinking to myself: I jumped out of airplanes for a living and I dove for a living in the Navy. But that was not dangerous. But you're worried about me being in Key Largo."

He has asked for a little help in one regard. In light of, well, a lack of natural light, Dituri is asking his friends and family for a facsimile: photos of the sun.

"I'm a creature of the sun, right?" he says. "So I wake in the morning, I go from my workout and I go watch the sunrise. And then on the way home from work, I stop at the bridge and I watch the sunset. So I am probably going to just chase that sun."

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