1The World’s Smallest Construction Workers
Coral reefs are some of the most spectacular sights on Earth, and they are built by tiny animals called polyps! These soft-bodied creatures are no bigger than a pea, but they are master architects. To protect their squishy bodies, each polyp pulls a mineral called calcium from the seawater to build a hard, stony cup around itself. When thousands of these polyps grow next to each other, their skeletons connect to form the solid foundation of a reef. Because they grow so slowly—sometimes only 1 to 10 centimeters a year—the massive reefs we see today have actually been under construction for thousands of years!
2A Superpowered Team-Up
Did you know that corals have a secret partnership with tiny algae called zooxanthellae? These algae live safely inside the coral's skin and act like tiny solar panels. They take energy from the sun to create food, which they share with the coral to help it grow. In return, the coral provides the algae with a safe home and the nutrients they need to survive. This amazing team-up is also what gives coral reefs their vibrant pink, orange, and purple colors. This is why reefs grow best in shallow, clear water—the algae need plenty of bright sunlight to keep their coral friends healthy and strong!
3The Rainforests of the Sea
Even though coral reefs cover less than 1% of the entire ocean floor, they are home to more than 25% of all marine life! Because of this, scientists often call them the "rainforests of the sea." These underwater cities provide food and shelter for over 4,000 species of fish, as well as sea turtles, octopuses, and crabs. From the Great Barrier Reef, which is so big it can be seen from outer space, to the small fringing reefs near tropical islands, these tiny architects create the most biodiverse ecosystems in our oceans.
