It is the water, covering about 70% of the earth’s surface. The greater part of hydrosphere is ocean rest is formed by river, lakes and ponds. Ocean water is saline and contains about 3.5 Kg. of salts in every 100 kg. Ocean water. Large number of organisms is found in hydrosphere compared to lithosphere. It is believed that life first originated in the hydrosphere and then entered into the lithosphere.