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.
Hyperventilation (a.k.a. overbreathing) occurs when the rate or tidal volume of breathing eliminates more carbon dioxide than the body can produce. This lowers the concentration of carbon dioxide dissolved in the blood leading to hypocapnia. The body normally attempts to compensate for this homeostatically but if this fails or is overridden, the blood pH will rise, leading to respiratory alkalosis.