New Tool Detects Coral Reef Bleaching In Near Real-Time

Now anyone can check if reefs under heat stress have started to bleach.

Dead table coral bleaching in Wakatobi National Park, Indonesia

kampee patisena/Getty Images

The coral reefs are in trouble. Yet much of that trouble is—for the vast majority of the world’s population—hidden out of sight. Unless you happen to be a scuba diver or snorkeler, or if you make your living from fishing, the impact or extent of coral reef loss is hard to visualize. 

Until now. 

A team of scientists—under the banner of the Allen Coral Atlas—launched what they describe as the world's first satellite-based global coral reef monitoring system. The monitoring system is designed to work with the Atlas’ other tools such as reef extent and composition maps. Much like the use of cyborg mussels as environmental warning systems, the full suite of Atlas is designed to provide near real-time data and insights on coral health.

This, the team hopes, will help scientists, conservationists, and policy makers alike to both understand how corals are being impacted by environmental changes, and also what measures are most effective in protecting them and helping them recover. Dr. Greg Asner, managing director of the Allen Coral Atlas, and director of the Arizona State University Center for Global Discovery and Conservation Science, described the launch as a significant breakthrough in the effort to protect reefs: 

“Our ability to monitor changes in coral reef condition has always been a clear but challenging requirement to drive decisions on where to apply our best restorative and protective strategies. The new Atlas Monitoring System is a major step in our effort to bring eyes to the reef at a global scale and yet with extraordinary detail needed for progressive reef interventions.”

The monitoring system itself works by capturing satellite imagery of known reefs and detecting changes in color that could indicate bleaching events. David Knapp, the senior scientific programmer, explained how the system captures and compares images over an extended period—rather than just a snapshot in time—in order to avoid interference from cloud cover or other disturbances:

“Every two weeks, we process a clean mosaic and look for pixels that have brightened consistently over the weeks that we monitor. We also check the NOAA CRW data every two weeks to see which regions around the world are at a bleaching status of “warning” or higher and we process the data for those regions until they are no longer in that status.”

According to Asner, the Atlas—which was developed as a collaboration between Arizona State University, Vulcan Inc., University of Queensland, Planet, and National Geographic—will eventually be expanded to monitor other threats besides heat-induced bleaching.

“It’s important for people to understand that this is just the first version of our monitoring system," Asner said. "We intend to improve and expand it to include a broader range of impacts on reefs such as land-sea pollutants and sediments. This first reef monitoring system is simply a drop in the bucket for what is to come.”

Given the significance of reefs both for global biodiversity and for fisheries that many people rely on for survival, a worldwide, publicly accessible tool that actively monitors the health of coral will be invaluable. The trick, of course, will then be translating the insights it provides into effective, policy-level interventions, as well as evidence-based restoration efforts at the scale and pace necessary to slow or even reverse the current disturbing loss. 

We’re not short of ideas for how to help coral. Hopefully, now, we will have a much better understanding of which ones actually work.