By Stacy Morford, Lamont-Doherty Earth Observatory
Attention surfers, divers, snorkelers, and other ocean enthusiasts: Those vibrant coral reefs below you need your help. In many parts of the world, corals are getting sick in the warm water accompanying El Niño, and they’re turning bone white.
It’s called coral bleaching, and in severe cases it can kill them over time. But while scientists know that coral bleaching has been connected to changes in water temperature, many questions remain about the causes and the recovery process.
To track the evolution of coral bleaching and home in on its triggers, a group of surfer-scientists at Columbia University’s Lamont-Doherty Earth Observatory has teamed up with the World Surf League and GoFlow to launch Bleach Patrol, a citizen science project and app. The app and website went live just ahead of spring break, as millions of people headed for the beaches.
Using Bleach Patrol, any surfer, diver, or ocean enthusiast out on the reef can become the eyes of the scientists and contribute to global understanding of coral reefs.
“By giving us that information, we can start targeting some very interesting scientific questions about what’s going to happen to corals over the next year or the next 10 years or the next 100 years. Is bleaching going to lead to a lot of coral mortality? Or will corals gain enhanced ability to recover from bleaching? These are all really important questions in the field right now. And hopefully with data from people who get to experience these reefs, we can start really chipping away at answering some of these hard questions,” Farmer said.
Healthy corals get their bright colors from photosynthetic algae called zooxanthellae that share their skeletal structure and provide food that keeps the coral alive. Under stress, however, these algae can produce oxidizing substances that the corals can’t handle. When a coral bleaches, it expels the algae, leaving a bone-white skeleton. Algae eventually recolonize most corals over the following months, but if that doesn’t happen, they can die.
NOAA puts out a coral bleaching map based on water temperature changes that generally coincide with bleaching events, but real-time reports from the reefs with details have been rare.
“Citizen scientists are crucial to the success of Bleach Patrol,” said Tim Greenberg, SVP of Digital for the World Surf League. “By making it easy for people all over the world to contribute data on their local reefs to the larger research project, we’ll be able to gain insights into the health of the global reef ecosystem more quickly and efficiently than any single research organization could do on its own.”
Lamont’s marine scientists will use the information uploaded to Bleach Patrol to target vulnerable and bleaching locations, both for sampling and for monitoring from high above via satellite. By sampling corals that have just recovered from bleaching, scientists hope to develop of a geochemical fingerprint of bleaching in the coral skeleton, and then compare that fingerprint to coral records through time to determine when bleaching events occurred in the past. They can also use Bleach Patrol reports to coordinate satellite images that can look back to the same location a few weeks and months before the bleaching event and follow the bleaching through time.
Diving on a coral reef (Photo: Brad Linsley)
Recognizing the Value of Reefs
Keeping coral reefs healthy is about much more than beauty. They protect coastlines from storm erosion and provide protective habitats for young fish and sea life and are relied on by some 500 million people worldwide. These ecosystems are important for medicines, and they contribute an estimated $30 billion to the world’s economies annually, according to NOAA.
“I think a huge point of value is not just the data that we’re collecting, but just to have people caring and getting involved and how that’s going to change their practices,” said Logan Brenner, a graduate student and scuba diver working on the project. “Even if they only make a few posts, the fact they were involved and felt like they were contributing I think increases accountability.”
NOAA’s Coral Reef Watch regularly updates a map of bleaching risk areas, with the highest risk areas in red. This is the map from March 2, 2016.
Where to Look?
Global episodes of coral bleaching have coincided with four recent strong El Niños, in 1982-83, 1998-98, 2010 and the event underway now. Hawaii saw severe coral bleaching last fall. Fiji is currently seeing coral bleaching.
Anyone living in or near Mauritius or Madagascar will soon be seeing peak bleaching, as well. Panama and Costa Rica are also in a special position right now—bleaching is just starting there, so reports of healthy reefs there and elsewhere can be just as important as reports of bleaching for tracking future bleaching, said Lamont research scientist and surfer Bruce Shaw.
“What we’re really asking people to do is snorkel out there, look at cool things, and come back. So I think it’s something that will both be fun and help you learn in a way that makes your appreciation for it much deeper,” Shaw said.
For people fortunate enough to live near a reef or visit frequently, the scientists are starting a program called “adopt a colony” to help track coral health over time. When you adopt a colony, you choose one area of the reef that you will return to regularly, give it a name in the app, and then provide regular updates and photos.
Distressed coral near Ft. Lauderdale (Photo: Barbara DeClerque '83SEAS)