CHAPTER 1 The Blue Planet The oceans are filled with a diverse array of life Rocky shores tropical coral reefs frigid polar seas even the black sunless deep The ocean is a collection of many habitats all bursting with life Oceans may seem too big and vast to be harmed by anything humans could do But the effects of human activities are everywhere habitat the natural place and conditions in which a plant or animal lives
FACT The average depth of the ocean is about 12 400 feet 3 800 meters Its deepest point is the Marianas Trench in the western Pacific Ocean The trench is more than 7 miles 11 kilometers deep All of Mount Everest the world's tallest mountain would fit into the Marianas Trench The mountain's top would still be more than a mile from the water's surface Trash washes up on shores all over the world Giant schools of tuna have been reduced to small isolated groups Huge heaps of trash cover large areas of ocean Dazzling coral reefs are becoming gray lumps of rubble The oceans and all of the life within them are in danger The oceans formed billions of years ago But it has taken less than 150 years to change them forever
Sea of Life Why Oceans are needed Why should anyone care what happens to oceans People live on dry land Many live hundreds of miles from the shore But what affects the oceans affects people too People around the world rely on the ocean as a main source for food About 3 billion people worldwide eat more than 112 billion pounds 51 billion kilograms of seafood per year That's 37 pounds 17 kg per person Additionally fisheries and aquaculture provide jobs for 540 million people worldwide The ocean is Earth's largest source of oxygen Oxygen is necessary for all life on Earth Green plants produce oxygen Phytoplankton are one kind of green plant in the ocean Billions of these one celled tiny plants produce half of all the world's oxygen Fishers unload their catch at a market in Sam Muk Chonbuti Thailand
Tiny green plants in the ocean produce most of Earth's oxygen aquaculture raising aquatic animals in water for human use phytoplankton different kinds of one celled organisms that live in water and provide food for larger creatures Phytoplankton make oxygen during photosynthesis carbon dioxide CO oxygen Sunlight H2O water phytoplankton
