Coral bleaching off the coast of Okinawa, Japan
Coral bleaching off the coast of Okinawa, Japan, in September 2016. Credit: The Ocean Agency/XL Catlin Seaview Survey/Stephanie Roach

A global bleaching event that devastated many coral reefs around the world from 2014 to 2017 has further raised the sense of urgency among coral experts to protect the reefs from damage from future elevated temperature conditions. The National Oceanic and Atmospheric Administration (NOAA) says the event is the third such global episode and the most widespread, longest, and most damaging bleaching event on record. This latest round of devastation is prompting scientists to examine potentially radical interventions.

A study by an ad hoc committee of the National Academies of Sciences, Engineering, and Medicine, which kicked off in February, is looking into the science, risks, and benefits of a range of possible interventions—some involving engineering, others mainly ecological or genetic—to help reefs recover and survive.

“The major problem that we are faced with is that our conventional methods of coral reef conservation that we have come to rely on are not keeping pace with the environmental change that we are seeing these days,” Ned Cyr, director of the NOAA Fisheries Office of Science and Technology, said on 8 February. He was speaking at the initial meeting of the committee, which is in fact-finding mode in its 2-year study of interventions to increase the resilience of coral reefs. NOAA, the study’s sponsor, has environmental stewardship responsibilities that involve coral science, coral assessment and management, and conservation of corals under the U.S. federal Endangered Species Act, said Cyr, one of several NOAA scientists who made presentations to the committee about the state of reefs and the agency’s goals for the study.

Coral reefs provide ecosystem goods and services such as fisheries, storm surge protection, and tourism. However, under stressful conditions such as higher than normal temperatures, bleaching can occur when corals expel symbiotic algae. This expulsion causes the corals to turn white and become more vulnerable to disease.

“We spend millions [of dollars] on coral reef marine protected areas, on implementing sustainable fishing practices, minimizing land-based sources of pollution, replanting reefs with live corals, etc., and yet these intervention methods simply don’t match the scale of what we are facing now from global warming,” Cyr remarked. Rising levels of atmospheric carbon dioxide are leading to changing pH and calcification conditions in the oceans that are having profound consequences for reefs, he added.

“We really need new solutions that match the scale of the problem.”

“We really need new solutions that match the scale of the problem,” Cyr said. “What we really need is a paradigm shift in our approach to conservation biology.”

Radical Interventions

The project scope for the committee’s study states that reefs are threatened by “rapidly deteriorating environmental conditions that are warmer, less favorable for calcification, have impaired water quality, and pose continuing disease threats.” The study calls for looking into strategies that include translocating nonnative coral stocks or species, managed selection, “stress hardening,” and engineering solutions such as shading and cooling reefs during bleaching events. “Although these interventions raise societal, policy, legal, and likely ethical implications for decision making, these considerations are beyond the scope of this review,” the project scope notes.

Some of the interventions “are not without controversy within the scientific community and the conservation community,” Cyr told the committee, mentioning, for instance, potential concerns about genetically modified organisms, or “frankenfish.” “Where you can help us is by helping to develop a consensus for the science and management community to justify the testing and the implementation of some of these novel techniques that we think ultimately are going to be helpful in our conservation mission.”

At the meeting, Jen Koss, director of NOAA’s Coral Reef Conservation Program, told the committee that although “radical solutions” are needed quickly, “we are mindful that these need to be reviewed.” She noted past examples of interventions in other ecosystems that led to significant problems, such as introducing kudzu for soil retention in the southeastern United States.

Committee Concerns

Committee members largely agreed with the scope of the problem and the need to do something quickly about it. “The conventional things that we are doing aren’t really working or certainly aren’t working well enough or fast enough,” committee member Nancy Knowlton told Eos. Knowlton is a coral reef biologist and the Sant Chair for Marine Science at the Smithsonian Institution. She is also a senior scientist emeritus at the Smithsonian Tropical Research Institute.

“We are faced with a situation here even in reefs which have been well managed with respect to, say, overfishing and pollution, which are the things that were problematic, say, a couple of decades ago,” Knowlton continued. Corals “are still being hit really, really hard by, particularly, global warming in these mass bleaching events.”

The committee is looking into potential ecological, genetic, and engineering interventions to help coral reefs. This aerial photo shows coral bleaching in March 2016 in New Caledonia, a French territory in the South Pacific. Credit: The Ocean Agency/XL Catlin Seaview Survey/Richard Vevers

An important consideration is weighing the costs and benefits of potential interventions such as moving species around the world, committee chair Stephen Palumbi told Eos, while bearing in mind those that have sometimes gone awry. Past failures are “a huge wake-up call” about the need to be “very careful” in considering and potentially using new interventions, added Palumbi, a professor of marine biology at Stanford University’s Hopkins Marine Station, Pacific Grove, Calif.

The goal is to have coral reefs “that can persist and thrive and still benefit humans even if we’re causing the climate to change into the future,” he said.

“We know that climate change is accelerating and accelerating bleaching. And so we need to make sure that this study isn’t something that talks about some nice areas of science but is too little and too late for the corals.”

Mark Eakin, coordinator of NOAA Coral Reef Watch, emphasized to the committee the need for quick, effective action. “We know that climate change is accelerating and accelerating bleaching,” he said. “So we need to make sure that this study isn’t something that talks about some nice areas of science but is too little and too late for the corals.”

—Randy Showstack (@RandyShowstack), Staff Writer


Showstack, R. (2018), Scientists examine novel options to save coral reefs, Eos, 99, Published on 18 April 2018.

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