As a diver scans the depth of the oceans, he faces several hazards like the high pressure under water, poor light conditions and low temperatures. Marine explorers have invented a variety of special equipments to ensure safe diving.
The equipment used by divers is called a SCUBA-or self-contained underwater breathing apparatus, also called an aqualung. This invention, by the famed oceanographer Jacques Cousteau and Emile Gagnan has revolutionized deep-sea explorations in the last 50 years. Many advances in SCUBA technology have now made the equipment easier to use, safer and more affordable, allowing not only professional divers, but also common people to take a trip into the deep seas.
The SCUBA equipment weighs about 30 kg. The breathing apparatus contains compressed air in a gas cylinder, maintained under pressure and fitted with a regulator. The regulator supplies air on demand. In addition, the apparatus has three other air containing apparatus for emergency conditions. One of them is a snorkel. A snorkel is a small, light breathing tube with a mouthpiece attached to your mask. When a diver comes to the surface the snorkel allows breathing of outside air.
The exhaled air goes out into the water in the form of bubbles. Some SCUBA equipment has a rebreather. A rebreather removes carbon dioxide from the exhaled air, and replaces the oxygen consumed during breathing from the apparatus.
Why is there a need for such foolproof breathing equipment? The air we breathe is a mixture of mostly nitrogen (78 percent) and some oxygen (21 percent). When one inhales, the body uses the oxygen and releases carbon dioxide. The nitrogen of the air remains dissolved in the blood and does not normally cause any problems. However, under water, the pressure of water is very high. As a result of this pressure, more nitrogen gets dissolved in the blood leading to life-threatening conditions. Moreover even oxygen under such high-pressure conditions can be toxic. It is therefore important that a diver gets the most natural air conditions to breathe. Thus, the body of a deep-sea diver is protected from the high pressure conditions under water by the special dress he wears.