History Īccording to Merriam Webster, the word hydrosphere was brought into English in 1887, translating the German term hydrosphäre, introduced by Eduard Suess. The average salinity of Earth's oceans is about 35 grams of salt per kilogram of sea water (3.5%). Approximately 71% of Earth's surface, an area of some 361 million square kilometres (139.5 million square miles), is covered by ocean. At any given time, about 2 × 10 13 tonnes of this is in the form of water vapor in the Earth's atmosphere (for practical purposes, 1 cubic metre of water weighs 1 tonne). The total mass of Earth's hydrosphere is about 1.4 × 10 18 tonnes, which is about 0.023% of Earth's total mass.

Of this fresh water, 68.9% is in the form of ice and permanent snow cover in the Arctic, the Antarctic and mountain glaciers 30.8% is in the form of fresh groundwater and only 0.3% of the fresh water on Earth is in easily accessible lakes, reservoirs and river systems. Saltwater accounts for 97.5% of this amount, whereas fresh water accounts for only 2.5%. This includes water in gaseous, liquid and frozen forms as soil moisture, groundwater and permafrost in the Earth's crust (to a depth of 2 km) oceans and seas, lakes, rivers and streams, wetlands, glaciers, ice and snow cover on Earth's surface vapour, droplets and crystals in the air and part of living plants, animals and unicellular organisms of the biosphere. It has been estimated that there are 1.386 billion cubic kilometres (333 million cubic miles) of water on Earth. This is caused by seafloor spreading and continental drift, which rearranges the land and ocean.

Although Earth's hydrosphere has been around for about 4 billion years, it continues to change in shape. The hydrosphere (from Ancient Greek ὕδωρ ( húdōr) 'water', and σφαῖρα ( sphaîra) 'sphere') is the combined mass of water found on, under, and above the surface of a planet, minor planet, or natural satellite. The Earth captured in the Pacific Ocean side

Covered by water drift