A search party is underway across the world’s coral reefs.
As warming waters turn more coral into bone-white deserts, scientists are looking for the species and regions with the best chances of resisting global warming.
To find these “hope spots,” divers are using creative methods to gather a greater number of observations from a wider range of reefs. Their bigger mission is to help steer conservation efforts toward the species that, with some extra protection, may be able to survive a warmer, more acidic ocean.
“There’s incredible value in having eyes on the reefs all over the world,” said Emily Darling, an associate conservation scientist at the Wildlife Conservation Society (WCS) in New York.
Darling is leading a new initiative to crowdsource data from scientists and savvy divers alike.
With a pencil, a clipboard, and a basic knowledge of corals, participants can jot down relatively simple observations about how coral responded to recent spikes in water temperatures. Did they bleach, for instance, and by how much?
Bleaching occurs when corals expel the symbiotic algae that give them their vibrant colors and provide corals’ main source of food. Without the algae, coral turn white and grow more susceptible to disease and death.
The surveys, refined over years of research, are designed so people can conduct them on their existing trips. After each outing, divers type their information into an Excel template, which WCS will later post online. Participants also revisit spots months later, to see which species recovered and which did not.
Darling said this approach could address two big challenges related to coral research. Given how remote and widespread reefs are, scientists often don’t observe corals until long after a bleaching event occurs. Another issue is that many researchers have focused on reefs in Australia and the U.S., while corals off the coasts of developing countries draw less attention.
Coral reefs are among the planet’s most diverse ecosystems and offer shelter and sustenance to everything from algae, worms, and snails to thousands of fish species and shellfish. They also provide vital food supplies for coastal communities and draw billions of tourism dollars each year.
Yet corals are facing unprecedented threats from human-caused global warming, which is raising water temperatures worldwide and causing the oceans to turn more acidic.
The world’s longest coral bleaching event in recorded history is still underway. The event, which began in June 2014, is now in its 34th month.
Previous bleaching events, by contrast, have lasted for less than 12 months, said Mark Eakin, who coordinates the Coral Reef Watch program at the National Oceanic and Atmospheric Administration (NOAA).
The primary cause of the nearly three-year-long bleaching event is “global climate change, driven by the increase in carbon dioxide and other heat-trapping gases in the atmosphere,” Eakin said.
While El Niño and La Niña events in the tropical Pacific Ocean have exacerbated bleaching, the ongoing global bleaching event began a year before the last El Niño and has continued well after the last La Niña, Eakin noted.
Coral bleaching has taken a particularly devastating toll on Australia’s Great Barrier Reef.
In 2015 and 2016, the iconic reef suffered its largest die-off on record due to unusually warm waters, with an average of 67 percent of corals in one area declared dead. Scientists had hoped 2017 would offer the Great Barrier Reef a reprieve, but found two-thirds of the corals have been impacted by coral bleaching in a 900-mile-long zone.
This summer, crowd-sourced WCS surveys will help scientists to see whether that bleaching has affected the wider Indo-Pacific region.
Austin Humphries, who studies coral reef fisheries at the University of Rhode Island, said he plans to conduct about 50 surveys during a four-month expedition to study fish in Indonesia.
“Bleaching is becoming an issue that we’re having to deal with more and more,” he said. “It’s important to get information quickly. We can’t sit around and wait for five years to go out and monitor a reef,” he added.
Humphries was among the dozens of participants who contributed about 300 surveys from the Indian and Pacific Oceans during the program’s initial phase. The results showed that, in 2016, more than 50 percent of the 70,000 coral colonies studied were bleached.
Wade McGillis, who studies coral heat stress and isn’t involved with the WCS program, applauded the idea of crowd-sourcing coral observations. He said such data are critical for helping experts decide where to return, and when, to gather more sophisticated measurements.
“Monitoring the day-to-day, and week-to-week changes of corals is very important,” said McGillis, a professor at Columbia University’s Lamont-Doherty Earth Observatory. “It’s spectacular having people to be the eyes and ears all over the place.”
McGillis said he’s a fan of citizen science in general. He works with a group of passionate kayakers and fishermen in the New York City area to conduct weekly water quality testing. He also helped advise the World Surf League on its Coral Bleach Patrol project, which allows surfers and snorkelers to upload photos and make simple observations via the goFlow app.
“Measurements, especially documenting and taking pictures of coral reefs — you don’t need a PhD to do that,” McGillis said. “So the contribution is enormous.”
Darling, the WCS scientist, said nontraditional approaches are key to not only identifying the more resilient spots but also identifying the most vulnerable corals that are in need of more urgent intervention.
“Climate change is an unexpected force; it’s not going away and everybody is trying to figure out what’s happening,” she said. “By working together, and reaching out to citizen scientists, this is really how we scale up our science to meet the challenges of global climate change.”