Open circuit scuba systems discharge the breathing gas into the environment as it is exhaled, and consist of one or more diving cylinders containing breathing gas at high pressure which is supplied to the diver through a diving regulator.
Also, breathing gas diluted with helium may be used to reduce the likelihood and effects of nitrogen narcosis during deeper dives. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Lambertsen in a patent submitted in 1952. The name 'scuba', an acronym for ' Self-Contained Underwater Breathing Apparatus', was coined by Christian J. Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply, and therefore has a limited but variable endurance. Recreational scuba diver The undersea kelp forest of Ana Capa off of the coast of Oxnard, California Diver looking at a shipwreck in the Caribbean Sea. Swimming underwater, breathing gas carried by the diver
