BBC Oceans: Atlantic Ocean

BBC’s underwater science program Oceans takes us to the Atlantic this time. First, marine biologist Pooni Mahti brings us to the Bahamas’ “Black Hole,” an isolated column of water mimicking chemically toxic conditions similar to the seas of three and a half billion years ago. After diving eighteen meters (60ft) deep through emerald green water, suddenly the temperature spikes by six degree centigrade (10F) and the water turns a cloudy shade of purple. The cause is a purple sulfur bacteria that traps the sunlight through photosynthesis, thus heating the water, and producing hydrogen sulfide....