Can humans live underwater?
Saturation diving allows the body to soak up inert gases by staying at depth for a long period of time. Usually, these gases would harm a standard scuba diver by expanding in their blood like bubbles in a shaken bottle of soda when the diver returns to the surface. This will cause pain, paralysis and sometimes even death.
Being "saturated" means that the diver's tissues have absorbed the maximum partial pressure of gas possible for that depth due to he diver being exposed to breathing gas at that depth for prolonged periods. This is significant because once the tissues become saturated, the time it takes to ascend from depth and decompress safely does not increase with further exposure. With the team never surfacing, after a dive and sleeping at depth, they benefit from being able to dive for up to 8 hours at a time, without suffering from decompression sickness. At the end of the mission, the capsule is brought back to normal pressure, allowing the built up gases withing the divers bodies to be released so that they can return back to the surface.
So how does living underwater affect us?
Taste
Many oceanauts claim that their tastes were diminished during their time beneath the surface. Divers have been found to put hot sauce on everything that they eat! Smell was almost non existent, meaning fewer particles are diffused for the nose to detect. Air particles are less likely to travel all the way to your nose! They also had to eat a lot more than they normally would in an unpressurised environment. The denser air and the long periods of dive time meant that to keep their body temperature normal, they needed a higher calorie intake.
Speaking and Breathing
Greater air density causes voices to sound much more high pitched on first entering the pressurised environment. However, after a time, either the ears adjust to this new pitch or it subsides, scientists are not yet sure which.
Teams have to be very careful not to catch any respiratory illnesses from their dive gear. If one person get sick, the whole team has to be brought back to normal pressure and resurfaced and the mission is over.
Sleeping
White noise can sometimes be heard from carbon dioxide scrubbers and also from surrounding marine creatures such as shrimps. Divers have been said to complain about small silvery fish swimming past the portholes reflecting lights into the bunk, keeping them awake at night.
Nitrogen Narcosis
Scientists have said that the capsules are not deep enough for the teams to experience nitrogen narcosis (a feeling of drunkenness due to a build up of nitrogen). However, divers that have been saturated for an amount of time (greater than 24 hours) have reported feeling a sense of giddiness.
Real life Experiments
One dream for one man in particular surprisingly enough became a reality when he set up an experiment to see if humans could live underwater for large amounts of time. Captain Cousteau put his idea to the test when he set up Continental Shelf 1, 10m below the surface just off of the coast of Marseilles in 1962.
Two men set out to put their bodies to the test and see if they could live in a cylinder 5m long and 2.5m in diameter, becoming the first "oceanauts" to live under water for a week. The capsule offered quite a few home comforts including a bed, a TV, radio and a library. They were monitored by 30 people on the surface and they each left the capsule for up to five hours per day to work in the ocean, investigating animals and building an underwater farm. It was a success and they continued their experiments in 1963 in the Red Sea with a star shaped capsule at 10m and 15m. After this second success, in 1965, 100m Conshelf III was born. 6 oceanuats lived there for three weeks working on a mock up oil rig. Conshelf III showed that humas could live underwater for prolonged periods of time.
“Conshelf proved that human beings can live under the sea for long periods of time but that, even though they have the physical and psychological capabilities, humans are not made to exist in a world without sun. Nevertheless, these experiments gave rise to the training astronauts undergo today before leaving for a world of billions of suns: Space. Here, too, Cousteau was a precursor.”
A human/'s psychology and state of mind may be affected by long amounts of time underwater. Normal sensations such as feeling the wind on your face or gaining vitamin D form sunlight is non existent during long missions.With more modern underwater habitats, oceanauts have wifi connection so can stream netflix and contact their friends and families. Boredom is not so much of a problem.
Since Conshelf I, II and III there have been many other underwater habitats set up for divers to be based underwater during working missions.
Aquarius is currently one of only three operational underwater laboratories. It is located just off of Key Largo in the Florida Keys National Marine Sanctuary. 19m below the surface, it sits next to a very deep reef called Conch Reef. The Reef Base is dedicated to science and education. Many undersea bases have lost their funding over the years. Aquarius stands as the last and is still used for research missions by marine biologists.
So, we can live underwater! All be it for limited periods of time, but it is possible. It has been said that if we were to extend a stay beneath the surface then eventually we would experience side effects. Breathing the denser air may lead to symptoms that would harm us. However, for the research that is being conducted at the moment, a maximum of 7-10 days is needed. And with wifi and netflix down there, who wouldn't want to be an oceanaut!