The 4-1-1 on Coral Bleaching

by Carey Morishige Martinez, Executive director, AIC Secretariat

Since summer, I’ve seen a seemingly unending flow of media headlines like these: “Coral Bleaching Outbreak Triggered By Warming Seas,” “State continues to monitor coral bleaching off Windward Oahu,” “Report: Reef showing signs of coral bleaching,” and “Scientists report coral bleaching off Kauai coast.” And, they keep on coming.

What does this mean? Why is bleaching happening?

I went looking for answers and here are some of the great resources I found:

bleachingWhat is coral bleaching? – NOAA National Ocean Service’s Ocean Facts
“When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white.”


Bleached coral within Florida Keys National Marine Sanctuary. NOAA NOS


What happens when a coral bleaches? – NOAA’s Diving Deeper (pub. 12/3/14)

“MARK EAKIN: You know when the water warms up, what happens is it’s actually good for the algae in one way in that it makes all of their photosynthetic apparatus run really great, but the problem is they run too fast; and as they run too fast they’re not able to repair themselves and the lack of repair causes the algae to start releasing compounds that are toxic to the corals. The coral sees this as, “whew, we’ve gotta get rid of you because if we don’t, we’re both going,” and they will actually eject the algae out from their tissues. They move them into the guts, spit them out—it’s a literal gut-wrenching experience when they do this. They’re breaking up pieces of tissue to get rid of this, to slough it off.”

Daily 5-km Satellite Coral Bleaching Thermal Stress Monitoring How do I know when bleaching might happen? There’s a site for that! NOAA’s Coral Reef Watch
“The NOAA Coral Reef Watch program’s satellite data provide current reef environmental conditions to quickly identify areas at risk for coral bleaching..”



Hawaii Eyes of the Reef trainingWhat Can I Do? There are SO MANY ways you can help!

GOT Training?
Join an organization like Hawaii’s Eyes of the Reef Network, Guam Community Coral Reef Monitoring Program, Southeast Florida Action Network (SEAFAN) BleachWatch, or Coral Watch. Help monitor and report coral bleaching in your area.

Bleached coral in American Samoa. NPSTeach others!
Check out these free lesson plans:

  • Coral Bleaching: A White Hot Problem – grades 9-12 from Bridge. Students “assess coral bleaching using water temperature data from the NOAA National Data Buoy Center.”
  • Caution: Do Not Bleach! – grades 9-12 from NOAA Ocean Service Education. Focuses on “Why are coral reefs important, and what are possible explanations for the phenomenon known as ‘coral bleaching?'”
  • Sea Surface Temperature and Coral Bleaching – grades 3-8 from NOAA’s Coral Reef Conservation Program. “Students will learn about the anatomy of coral bleaching, how ocean temperature increase can be a cause of coral bleaching and will try to predict general areas likely to be affected by coral bleaching by interpreting sea surface temperature data.”
  • Coral Bleaching: Turning Up The Heat – grades 5-8 from the National Park of American Samoa. Students will be able to define global warming and adaptations and ID several coral reef species in American Samoa.

Now you know and as GI Joe says, “Knowing is half the battle.” 😉