This passage discusses the function of ocean reefs.

Lexile Level: 1070L

Categories: Animals & Nature

A coral reef may look like rock, but in fact, it's full of life. A coral reef is like a giant underwater apartment complex with coral polyps living in each unit. Reefs are usually found in warm, tropical waters. Choppy waves bring in food, nutrients, and oxygen. Reefs also need sunlight to grow algae, which provide food and oxygen to animals living there. Although they make up only about one percent of the ocean floor, coral reefs house more than 25 percent of ocean life, including sea urchins, sponges, sea stars, worms, fish, sharks, lobsters, shrimp, octopi, and snails. Corals can be white, pink, red, green, blue, orange, or purple. Beautiful, colorful reefs have existed for millions of years. But coral reefs are in trouble. More than a quarter of them have been destroyed by pollution and careless human activity. Unless something is done soon to save them, all of the reefs could die in the next few decades.


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