When diving, Scuba divers breathe gas under pressure. The greater pressure causes the nitrogen in the breathing gas to dissolve in their bodily tissues (the body metabolises the oxygen).
When the diver ascends from depth, the pressure is reduced, and so the gas comes out of the tissues and into the bloodstream, where the diver expels it through his lungs. Normally these bubbles are very small (sometimes called "micro" bubbles or "silent" bubbles) and present no risk to the diver.
Normal off-gassing in this was is not harmful, but if a diver stays too deep for too long, the rapid release of gas can form larger bubbles which can cause decompression sickness. In minor cases this can cause discomfort and localised swelling, which can normally be resolved with oxygen. Severe cases can lead to permanent tissue damage, paralysis and even death. This is why divers are trained to understand no-decompression limits and to utilise tables or dive computers to keep them safely within margins.
If they don't then small bubbles can form in their blood, and in some severe cases it can kill them.
There isn't a specific collective noun that is universally recognized for a group of scuba divers, but some suggestions that have been used informally include: A "school" of scuba divers A "team" of scuba divers A "group" of scuba divers A "buddy" of scuba divers These terms are not as commonly used or established as collective nouns for some other groups of animals, but they can be used informally in conversation or writing to refer to a group of individuals who are scuba diving together. Ultimately, you can choose whichever term you feel best suits the context.
scuba divers
Free divers do but scuba divers do not need to. Scuba divers take their air with them and would have no need to hyperventilate.
They swim
seebees
In the Water....
scuba divers
Scuba - self contained underwater breathing apparatus
Scuba Bob's Ocean Quest - 2006 Fearless Divers Scuba Rangers 2-7 was released on: USA: 2007
That only occurs when divers remain under longer than the recommended no-decompression limits. But it is done to allow the body to slowly rid itself of nitrogen that has built up in the bloodstream due to breathing pressurized air at depth. If it isn't done, the bubbles pop in a blood and cause decompression sickness, which is very dangerous.
Skin divers are people who dive into the ocean without using special equipment, unlike Scuba divers.