Diving Gases
Diving is thrilling. It gives you the feeling of exploring the unexplored and going where no one else has ever ventured. The deep blue sea is alluring. Only about 1% of the deep parts of the ocean have been explored, so it’s natural to be curious about what lurks in the blue abyss that drops out below you. It’s a world that once you are in it; you often don’t want to leave.
Most divers dive with air, which is a mix of 78% nitrogen, 21% oxygen, and 1%, other gases. It allows you to safely venture to 132 feet or 40 meters below the ocean surface. This is where the majority of sea life lives and is plenty deep for any recreational diver. If you dive any deeper you are at more risk for nitrogen narcosis and decompression sickness, not to mention that you use your air much quicker. It’s just dangerous.
Science divers often need to go deeper or stay longer. It may be that they are researching algae that only live hundreds of feet below the surface or they are observing an electric eel feeding. When this happens they need to use a different air mix. This means that they are changing the normal mixture of 78% nitrogen, 21% oxygen, and 1% other gases to allow them to dive deeper or stay longer. There are two main air mixes that allow divers to do this. They are Nitrox and Trimix.
Nitrox is a common air mix. Recreational divers can become certified nitrox, or enriched air, divers. Nitrox increases the amount of oxygen in the mix. It usually boosts the oxygen percentage to 32 or 36 percent. Nitrox increases the amount of time a diver can stay underwater without risk of decompression sickness, but does not necessarily increase how deep they can go. Nitrox increases your risk of oxygen toxicity if you go too deep, but decreases your risk of decompression sickness. It also reduces fatigue. These are all benefits for science divers that are doing repetitive dives in relatively shallow waters and want to maximize bottom time.
Trimix is the most common type of air mix if you want to dive deeper. Instead of only mixing oxygen and nitrogen, it also adds a third gas - helium. The addition of helium to the mix decreases the amounts of the other gases and allows divers to decend up to 100 meters. Using trimix also means more training and more responsibility. You need to have an intricate understanding of diving physics, be prepared to follow exact instructions for filling air mixes, and be able to carry extra trimix tanks and travel air to allow for safety stops and safe travel through shallower waters.
Air mixes add a whole new element to diving. They open up new doors and allow for longer and/or deeper diving. With proper training and procedures, air mixes truly benefit the scientific diving world.
