April 18, 2024

By Ethan Yan. (Student Journalist)

Coral reefs are one of the most beautiful underwater habitats the earth has to offer, but many of them are dying due to the same factor killing off many of the world’s other habitats, climate change. 

Many of you have heard of the greenhouse effect, where light penetrates greenhouse gasses in the atmosphere, is converted into heat when it hits the earth’s surface, and can’t escape. This greatly contributes to much of the extinction happening here on earth, as recent temperatures have risen much higher than they should be. Sure, organisms can adapt to heat, but currently, the world is changing much faster than most creatures can keep up with. One of these organisms is coral, which is dying in massive numbers due to these changes in ocean conditions.

Bleaching is when coral loses much of its color due to warmer than usual ocean conditions. Zooxanthellae, the type of photosynthetic algae which resides within these coral, provide the coral with oxygen, glucose, and amino acids, which allow the coral to  thrive, in return for shelter within the coral’s hard, bony structure. These algae are also the ones responsible for giving the coral its color. The corals thrive best when the zooxanthellae also thrive, but when waters get too warm, the algae leaves the coral, resulting in a bleach. Bleached coral appears white, and when it is bleached, it is not completely dead. Instead, it is very stressed, which can result in death.

Bleaching, usually, is a result of warm water. However, while that is the most common form, there are many other ways a coral can bleach, including cold temperatures, sunlight exposure, exposure to air, and pollution. With more extreme weather and pollution due to climate change, as warm weather isn’t the only thing it brings, these other bleaching factors increase, too.

So how do we fix this? Some scientists are out in the reefs, in restoration projects. They can first cut off a snippet of coral, which, since the coral is many polyps combined into one organism, can be separated and have the new part grow into a complete organism. Scientists then strap these pieces on a reef in the ocean as soon as they grow big enough, which will replenish the reef. Scientists are also looking into selectively modifying corals via artificial selection so that they are more resistant to bleaching, and thus can survive in the reefs.

Climate change is a persistent issue, though, and it’s not just coral being affected by it. Many other organisms here on our planet are struggling, too. So next time you leave the room, turn off the lights, buddy.