combined mass of water found on, under, and above the surface of a planet, minor planet or natural satellite

The hydrosphere is the total mass of water on, under, and over the surface of a planet. It is part of physical geography. The oceans, rivers, and lakes are all part of the hydrosphere. Some electricity is made by the hydrosphere.

The total mass of the Earth’s hydrosphere is about 1.4 × 1024 grams, which is about 0.023% of the Earth’s total mass. Around 2 × 1019 grams of this is the Earth’s atmosphere. In addition, 71% of the Earth’s surface, an area of 361 million square kilometers, is covered by ocean.[1]


  1. World Water Resources: a new appraisal and assessment for the 21st century (Report). UNESCO. 1998. [1]