the hydrosphere composes approximately what percent of the earths surface
Ocean The total mass of the hydrosphere is about 1.4 quintillion metric tons (7018140000000000000♠1.4×1018 long tons or 7018150000000000000♠1.5×1018 short tons), which is about 0.023% of Earth's total mass. Less than 3% is freshwater; the rest is saltwater, almost all of which is in the ocean. The area of the World Ocean is about 361.9 million square kilometers (139.7 million square miles),[9] which covers about 70.9% of Earth's surface, and its volume is approximately 1.335 billion cubic kilometers (320.3 million cubic miles).[9] This can be thought of as a cube of water with an edge length of 1,101 kilometers (684 mi). Its average depth is about 3,688 meters (12,100 ft),[9] and its maximum depth is 10,994 meters (6.831 mi) at the Mariana Trench.[29] Nearly half of the world's marine waters are over 3,000 meters (9,800 ft) deep.[16] The vast expanses of deep ocean (anything below 200 meters or 660 feet) cover about 66% of Earth's surface.[30] This does not include seas not connected to the World Ocean, such as the Caspian Sea.