Why Are Coral Reefs Worth Protecting?

Did you know that we rely in part on coral reefs to help produce the oxygen we breathe? Author Maris Wicks explains the water cycle, coral bleaching, and what we can do to help protect coral reefs.

Sabrina Stierwalt, PhD
9-minute read
Episode #260

photo of Maris Wicks at a coral reedAs a parent, nothing is more humbling than when your child starts asking science questions that you don’t know the answers to. That’s why I was so excited to discover the science comics written and illustrated by Maris Wicks that delve into the science behind topics like primates and the human body with the help of lots of colorful pictures and fun story telling.

I got the opportunity to chat with Maris Wicks about her book called Coral Reefs: Cities of the Ocean. Thank you for being here, Maris!

EE: Your book covers a lot of ground on coral reefs, from types of coral to the coral life cycle, and even insights into the scientific method like categorizing by genus and species. What do you find most fascinating about coral reefs? Of all the things in the ocean—and across science—that you could have written about, what made you choose coral reefs?

MW: I love the whole ocean. Bonus fun fact: my name Maris actually means "from the sea" or "from the ocean." I grew up in New England and the closest ocean to me is pretty cold ocean water with intertidal animals (sea stars, hermit crabs, snails) and the coral reef was really a place that I never imagined myself ever going to. So I think that’s what kind of started my interest—a habitat or an environment that I had never been able to see before. And then once I got older, the incredible amount of biodiversity or just the amount of different animals that live in a coral reef I found fascinating. It’s kind of like visiting a really big city for the first time. So you have all these different people from all over living in one place doing all these different things and a coral reef is the same except instead of people you’ve got lots of different animals and some of those animals eat each other to survive.

Why are coral reefs important?

EE: In your book, our adorable little goby fish narrator explains that one billion people depend on coral reefs directly and then even more so do indirectly. Why are coral reefs important to humans?

MW: The number for the one billion people just has to do with how many people live near the ocean worldwide and how many people live in warmer areas near the ocean worldwide. But the rest of the world that doesn’t live near the ocean or lives near a colder ocean needs coral reefs just as much as people who live near them. The folks that live nearby are using the coral reefs for food or for work like fishing or using the ocean’s resources. We might do the same as well living far away. But without coral reefs, if you take them out of the picture, the rest of the ocean would suffer. Coral reefs are a really big puzzle piece to the puzzle that is Earth, and if you take them out the rest of the Earth can’t really survive as well. If coral reefs went away then fish and ocean animals all over the world would decline or disappear. And if that happened – this kind of gets me scared to think about this because I don’t want coral reefs to go away! They are really really important! – but if coral reefs weren’t there it wouldn’t just be the fish and whales and turtles, even small things like phytoplankton which are teeny tiny plant plankton in the middle of the ocean. If they were to go away then we would have less air to breathe on this planet. You need coral reefs for the planet to be healthy even if you don’t live near them.

What is coral bleaching?

EE: So the thought of coral reefs going away sounds super scary, and we hear about coral bleaching and I knew that it was linked to the death of the coral, but until reading your book, I didn’t realize exactly what causes it. Can you tell us what is coral bleaching?

MW: Yeah! Coral bleaching—I think before we can talk about it, we have to talk about coral’s very special relationship with teeny tiny algae named zooxanthellae which is my favorite science word in all of science: "zooxanthellae." Corals and zooxanthellae live together in perfect harmony. It’s a symbiotic relationship. The corals need the zooxanthellae to survive and the zooxanthellae need the corals to survive. The corals hang out there with the zooxanthellae, these little tiny algae-like plants, all over them and the zooxanthellae—for having a home that is the corals—will give the coral in return oxygen and food and really bright colors. If the temperature in the ocean nearby the corals increases or just goes up too much—if it gets too hot—the zooxanthellae say, “Ah! It’s too hot! We can’t survive here anymore! We’re outta here!” and they actually leave the corals.

So what happens is that not only do the corals lose their beautiful colors, they also lose their major source of food and oxygen which is a HUGE problem. The good news is that if the temperatures go back to normal or if it’s not too big of a temperature increase, the zooxanthellae might come back and the corals can recover. But if the temperature increases too much—if it gets too hot—the zooxanthellae will leave which means that the corals can survive for a little bit but eventually they’ll die. That’s one of the big scary parts that I think about. Because you do hear a lot about coral bleaching and you ask, “What is it? Is someone going in and bleaching the corals?” The reason why the word “bleaching” happens in there is because the corals literally turn white because their zooxanthellae friends are gone.


Please note that archive episodes of this podcast may include references to Ask Science. Rights of Albert Einstein are used with permission of The Hebrew University of Jerusalem. Represented exclusively by Greenlight.

About the Author

Sabrina Stierwalt, PhD

Dr Sabrina Stierwalt earned a Ph.D. in Astronomy & Astrophysics from Cornell University and is now a Professor of Physics at Occidental College.