The world's oceans cover 70% of Earth's surface. And they contain roughly 321 million cubic miles of water. Yeah, we're talking cubic miles here. How much is that? 46.8 BILLION gallons of seawater for every person on the planet! In other words, the ratio of you to the amount of seawater on the planet is 1:71,000 Olympic-size swimming pools. All that water, of course, contains an incredible abundance of life. There are over 220,000 identified plant, animal, and other species in the world's oceans. And estimates suggest there are as many as 2 million species in the seas that remain undiscovered. But the ocean water ... (full story)