1 Great Barrier Reef Is Visible from Space The Great Barrier Reef is a chain of coral along the northeast coast of Australia It’s bigger than the Great Wall of China It’s the only life form large enough to see from space It’s the world’s largest structure made of life forms The reef has been growing for 500,000 years Coral polyps are animals in the jellyfish family They join together to make reefs A reef is made up of hundreds of thousands of polyps Algae live inside the corals The corals protect the algae from other marine life The algae make food for the coral The algae also make a limestone skeleton for the coral The algae give corals their beautiful colors This NASA space image shows the reef is not a single reef but a vast maze of reefs passages and coral islands
CORALS IN DANGER Corals need water between 70 and 100 degrees Fahrenheit 21 to 38 C to live Global warming caused by mining and burning fossil fuels like coal is making the oceans warmer In recent years warmer ocean waters have been killing corals in the Great Barrier Reef 10 percent of the world’s fish species live in the Great Barrier Reef 2 million Number of people who visit the Great Barrier Reef each year The Great Barrier Reef is a huge coral structure Coral polyps and algae grow to form the reef The reef is home to thousands of colorful sea animals The Great Barrier Reef is home to all kinds of marine life Whales dolphins and porpoises live there Over 1,500 fish species and 5,000 mollusks are found on the reef Sea snakes turtles crocodiles and seabirds abound The bright colors of the fish and the clear blue water are a favorite sight of visitors People from all over the world come to the Great Barrier Reef They can scuba dive snorkel Jet Ski skydive or ride in glass-bottom boats
2 Challenger Deep Is Dark Cold and Very Deep The Challenger Deep is a point on the Mariana Trench It is in the Pacific Ocean between Japan and Papua New Guinea It is the deepest point in all the oceans of Earth If Earth’s tallest mountain were put in the trench it would still be covered by more than a mile of water Earth’s crust is made up of huge plates that float on a layer of hot rock The Mariana Trench was formed where two plates bumped into each other One plate was pushed downward This made a huge canyon on the ocean floor In 1875 the British Royal Navy first measured the trench in a ship named the HMS Challenger A second British ship with the same name returned Maug is a volcano in the islands along the Mariana Trench
down to the Challenger Deep The trench is a hard place to explore because it is so dark and cold The water pressure is too high for most animals to survive Crustaceans sea cucumbers amoeba like creatures and bacteria live in the deep waters Cusk eels are common in the deep sea Depth in miles 11 km of Challenger Deep The Challenger Deep is the deepest known point in any ocean on Earth A collision between two plates of Earth’s crust formed the trench Explorers have found 6 8 microbial life forms in the Deep 7 to measure the trench in 1951 The Deep is named after these ships Only three explorers have descended into the Deep Swiss engineer Jacques Piccard and US naval officer Don Walsh traveled down in a Navy seacraft in 1960 In 2012 Canadian filmmaker James Cameron went THINK ABOUT IT Thousands of climbers have made it to the top of Mount Everest the highest place on Earth Only three people have gone down to the Challenger Deep Why is this
