yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Coral Reefs 101 | National Geographic


2m read
·Nov 11, 2024

(Gentle music) - [Narrator] Coral reefs, their bright, vivid colors can be seen in tropical ocean waters around the globe. Beyond their brilliant appearance lies a hidden significance.

Coral are animals. Though they may look like colorful plants, coral are, in fact, made up of tiny animals called polyps. These invertebrates can range from the size of a pinhead to a bit larger than a basketball. Each polyp consists of a soft, saclike body topped by a mouth covered in stinging tentacles. To protect their soft bodies and add support, the polyps secrete limestone skeletons, or calicles.

Corals are mega builders. Polyp calicles connect to one another, creating a colony that acts as a single organism. As colonies grow over hundreds and thousands of years, they join with other colonies and become reefs that can grow to hundreds of miles long. The largest coral reef is Australia's Great Barrier Reef, which began growing about 20,000 years ago.

Coral reefs are some of the most diverse ecosystems on Earth. Though they cover less than 1% of the ocean floor, coral reefs are home to 25% of all marine creatures. It's been estimated that up to two million species inhabit coral reefs, rivaling the biodiversity of the rain forest. The reefs provide rich habitat that helps protect young fish as they grow.

Coral are translucent. Coral reefs get their rainbow of colors from algae, or zooxanthellae, that live in their tissue. Though corals use their tentacles to capture some food, most of their food comes from the algae they house. When coral become stressed by pollution or other factors, they evict their algae. Coral bleaching results, revealing corals' white skeletons.

Coral provide a window to the past. As coral grow, their limestone skeletons form layers, similar to tree rings, that vary in composition and thickness based on ocean conditions at the time. With some coral reefs growing for thousands or even millions of years, scientists can study these layers to reveal what the Earth's climate may have been like in the ancient past.

Unfortunately, climate change is putting coral's future in danger, along with the millions of species that inhabit the reefs and the half-billion people that rely on reef fish for food. Warming waters result in prolonged coral bleaching that kill coral reefs or leave them vulnerable to other threats. Without significant action on climate change, our oceans could lose many of their colorful reefs by the end of the century.

More Articles

View All
How To Use The 2023 Market Crash To Get Rich
What’s up guys? It’s Graham here. So today, we have to answer the age-old question that philosophers and economists have pondered since the beginning of time, and that would be: Am I wearing pants? And the answer is no. Just kidding! Instead, it’s whether…
Introduction to meditation to reduce test prep anxiety
Hello, Sal here from Khan Academy. So when you hear the word meditation, for many of y’all, it might evoke some type of new age thing that has nothing to do with standardized tests. And if you’re about to take a standardized test, I’m sure there’s many t…
Text Messaging Helps Elephants and People Coexist | National Geographic
You know India has the highest number of Asian elephants, and there are millions of people living very close to or within the elephant landscapes. Between 1994 and 2015, 41 people lost their lives in direct encounters with elephants because people didn’t …
Mary Devotion Around the World | Explorer
[Music] I was approached by National Geographic last year to photograph people’s relationship with Mary. I traveled all around the world to some of the most unexpected places to document this project. I have my own questions about my faith. I was raised C…
Why Is Your BOTTOM in the MIDDLE?
Hey, Vsauce. Michael here. A human, running like a quadruped, is creepy. Artist Rui Martins created this animation about a year ago. 127 years ago, Eadweard Muybridge shot these real images of a child with infantile paralysis walking on all fours. Walking…
Misconceptions About Falling Objects
Let’s say Jack holds both balls above his head and then he drops them at exactly the same time. What do you expect to see? Well, they’re going to hit the ground at the same time. I expect them to both land at the same time. The same time, same time! This…