Contents 6 Oceans 8 The Sunlight Zone Coral reefs and whales 10 Superhighway Fishing shipping and drilling 12 The Twilight Zone Crustaceans and squid 14 Exploring the Seabed Diving and filming below 16 The Midnight Zone Sharks and cuttlefish 18 Deep sea Discoveries A world of sponges 20 The Black Abyss Hot vents and frilled sharks 22 Secrets of the Abyss Searching for new species 24 The Ocean's Trenches Earth's deepest valleys 26 Taking the Plunge Technology at depth 28 Fantastic Ocean Facts 30 The Future 31 32 Glossary and Index
Oceans Earth's oceans are vast connected bowls of dark basalt rock Oceans cover 72 percent of the world and provide 70 percent of our oxygen These oceans filled with water that was created by gaseous clouds blowing over prehistoric Earth Ocean crusts began to form less than 200 milion years ago and now hold water at an average depth of 13 000 feet 4 000 meters The Sunlight Zone From the sunny surface to about 660 feet 200 m deep the continental shelf slopes down gently at this level The Twilight Zone From 660 feet 200 m to 3 300 feet 1 000 m with faint light the continental slope dips deep into the ocean The Midnight Zone From 3 300 feet 1 000 m to 13 100 feet 4 000 m where creatures adapt to darkness and heavy water pressure The Abyss From 13 100 feet 4 000 m to 19 700 feet 6 000 m the continental rise reaches gently up from the abyssal floor RAL The Trenches From 19 700 feet 6 000 m to 36 100 feet 11 000 m where steep sided narrow valleys plunge down
