Name: What is Coral Bleaching?
Uploaded: undefined
Duration: undefined

Nova

Ives Family Fund

Koch Foundation

NOVA Science Trust Logo

When coral polyps are stressed they become bleached by ejecting tiny algae cells that normally live inside them and provide food and color. This somehow compromises their relationship with surrounding fish communities and reduces the overall dynamism and health of the reefscape.

It changes the dynamic of the entire reefscape, and can be detrimental to corals.

It changes the dynamic of the entire reefscape, and can be detrimental to corals and the animals that depend on them.

What is Coral Bleaching?

It changes the dynamic of the entire reefscape, and can be detrimental to corals and the animals that depend on them.

Planet Earth

What is Coral Bleaching?Published: February 26, 2019Onscreen: What is coral bleaching? Reefs are built by microscopic animals called coral polyps.Ruth Gates: A polyp is a little type of animal. A ring of tentacles around a mouth. That is over a stomach. You’ll see thousands of repeated polyps that create a coral colony. Inside the polyp’s tissue live tiny plant-like algae cells. Using the sun’s energy they make food for the coral polyp. In return the coral provides carbon dioxide and shelter.So the animal and algae combination is absolutely mutualistic and co-dependant. That means both benefit from the relationship and they die if they’re separated.Onscreen: If the water around the coral gets too warm the animal ejects algae cells.Gates: The animal now sees the algae as being a foreign body and tries to get rid of it as quickly as possible. Which is a bit of a problem when you think that it’s the algae that’s feeding the animal.Onscreen: The result is coral bleaching.Gates: What we’re really talking about here is the visual paling of the normally dark-brown corals turning white. A bleached coral is a coral that is likely to die. A bleached coral somehow doesn’t communicate well with the fish communities. There’s some change in the overall dynamic nature of the reefscape. And you can detect it when you’re on a bleached reef prior to it dying. It is different, it is more resilient, it is quieter. It doesn’t feel right. We have lost 50% of the world’s reefs in the last 30-40 years. That’s...I mean...even when I say it, I have to be honest I still find it shocking and I want to find a reason for that figure to be wrong but it’s not wrong.

United States

Northern Mariana Islands

Puerto Rico

American Samoa

Guam

U.S. Virgin Islands

U.S. Minor Outlying Islands

US & Territories

NOVA investigates the story of cannabis from the criminalization that has disproportionately harmed communities of color to the latest medical understanding of the plant. What risks does cannabis pose to the developing brain? How much do we know about its potential medical benefits? As cannabis becomes socially accepted, scientists are exploring its long-term health consequences. (Premiered September 29, 2021)Check out a previously recorded panel discussion and audience Q&amp;A featuring experts and producers from "The Cannabis Question" <a href="https://youtu.be/nSTT5RZ_hxA">here</a>.

As state-legalized cannabis spreads, NOVA explores its little-known risks and benefits.

The Cannabis Question

A 2006 composite image from NASA's Hubble Space Telescope and Spitzer Telescope shows the chaos of baby stars in the Orion nebula some 1,500 light-years away. Image Credit: NASA/JPL-Caltech/STScI

With the upcoming launch of the James Webb Space Telescope, the Hubble era is gradually drawing to a close. Here are some highlights from the countless wonders Hubble has shown us during its 31 years in space.

10 spectacular Hubble Space Telescope images

A statue of Zheng He at the Sam Poo Kong Temple in Java, Indonesia. Image Credit: Budianto Santosa, Shutterstock

In the 1400s, Zheng He sailed thousands of miles around Asia and Africa in ships the size of soccer fields, spreading Chinese innovations like compasses and gunpowder in the process.

What is Coral Bleaching?

Support Provided By

Explore More

Palau’s Improbably Healthy Coral Reefs

Decoding the Weather Machine

Why There's No Climate Hoax

Transcript

Credits

Support Provided By

Explore More

Palau’s Improbably Healthy Coral Reefs

Decoding the Weather Machine

Why There's No Climate Hoax