Sea-water as an ore

The most accessible oceanic ore is sea-water, and a vast resource it is. Covering approximately 71 per cent of the earth's surface, its total volume is calculated at 1,370 million km³ and its surface area at 361 million km². Of all waters on the planet, only a little more than 1.2 per cent occurs outside the oceans—1.2 per cent as ice, 0.002 per cent as rivers and lakes, and 0.0008 per cent as vapour in the atmosphere. ¹