Its average depth is about 3,688 meters (12,100 ft), and its maximum depth is 10,994 meters (6.831 mi) at the Mariana Trench. Nearly half of the world's marine waters are over 3,000 meters (9,800 ft) deep. The vast expanses of deep ocean (anything below 200 meters or 660 feet) cover about 66% of Earth's surface.
hyperventilation. 1. increase of air in the lungs above the normal amount. 2. abnormally prolonged and deep breathing, usually associated with acute anxiety or emotional tension. A transient, respiratory alkalosis commonly results from hyperventilation. More prolonged hyperventilation may be caused by disorders of the central nervous system, or by drugs.
All of these symptoms are the result of abnormally low levels of carbon dioxide in the blood caused by overbreathing. The term hyperventilation syndrome (HVS) is sometimes used to describe the effects of hyperventilation observed in an emergency department setting. Many acute (sudden onset) cases of hyperventilation arise from panic, anxiety, and other emotional conditions.