ASU working to save Hawaiian coral reefs during onset of new ocean heat wave


Joe Caspermeyer

Editor's note: Be sure to check back on ASU Now for this developing story, and the website as we provide further updates. Or follow us on social media: @asnerlab — @greg_asner — @asunews — #coralbleaching2019

ASU scientists map the Hawaii's coral reefs during a bleaching event

ASU Robin Martin and Patrick Gartrell are shown in the field measuring living and coral dying coral in preparation for the ocean heatwave in Hawaii.

UPDATE: Sept. 24, 2019

Ocean cauldron is creating widespread coral bleaching across Hawaii

In Hawaii, citizen scientists have sprung into action to help save the greatest source of ocean life diversity, its coral reefs during record breaking high temperatures this summer.

National Oceanic and Atmospheric Administration (NOAA) predicted in early August that there would be a widespread and severe bleaching event in the coming months after tracking a “blob” of warm water moving toward the Pacific, akin to one that triggered widespread bleaching in 2015.

Now, the blob has arrived.

This time, NOAA, the DLNR Division of Aquatic Resources (DAR), and the Arizona State University Center for Global Discovery and Conservation Science (ASU-GDCS) have joined forces to collaborate on coral reef science, conservation and management in Hawaii.

An ASU effort shows One of the outcomes of this partnership is the creation of a coral bleaching alert card, which depicts a list of six steps  people can take to reduce any additional stress on corals during the current bleaching event. 

ASU-GDCS research scientists recently hit the streets to distribute these cards to local dive and local tourist shops.

With a better-informed community, everyone is doing their part to help save the coral reefs.

A local dive shop holds ASU tips on how people can help preserve coral reef health

The Governor’s office issued another statement to raise awareness, and last week, a team from DAR conducted a rapid assessment of coral health at Molokini and along Maui’s south shore from Makena to Maalaea.

 The National Coral Reef Monitoring Program surveyed the Papahānaumokuākea Marine National Monument and found extensive bleaching. At Kure Atoll, the northernmost atoll in the archipelago, almost 100 percent of shallow-water corals (less than 15 feet deep) are bleached. Severe coral bleaching is predicted to extend across the Hawaiian Archipelago, and citizen science reports of bleaching have confirmed this widespread bleaching.

Russell Sparks, a DAR Aquatic Biologist reported, “Molokini is composed of high percentages of the coral species, Montipora capitata, and we found roughly 50% of this coral already bleached or paling heavily.”  The DAR team found in waters off Makena, Wailea, and Kihei the percentage of corals showing bleaching currently at less than 10%. 

Warm ocean temperatures are expected to persist in the coming weeks, likely worsening the coral bleaching that has recently been observed across the islands.

 ASU-GDCS has been focused on monitoring on Hawaii’s Big Island, and has seen similar bleaching in the pristine waters of Papa Bay. 

A team of divers from ASU is monitoring the health of coral reefs

 “We just finished installing 6 new fish camera traps in #Hawaii to monitor changes in fish communities during and after the bleaching event," said Greg Asner, director of ASU=GDCS. "We're geared up and ready to finish pre-to-early coral bleaching measurements as the ocean heatwave intensifies. Using fish camera traps, underwater temp sensors, and PLANET labs satelliate imagery, we're tackling coral reef research from above and from below."

Coral bleaching on Hawaii's Big Island

 Why are so many coming together to help save coral reefs?

 For the sea, coral reefs are like the rain forests on land in their support of biodiversity (see

 According to Hawaii’s Division of Aquatic Resources,, even though coral reefs cover just a tiny fraction of the ocean floor, they support almost one-third of the world’s marine fish species. Yesterday, with alarming news of up to 3 billion, or almost one-third of the entire bird-population of North America lost due to human activity, the fear is that the oceans are next. 

 Sometimes corals are able to recover from bleaching. However, they can die if stressors, such as warmer ocean temperatures, continue. Studies have shown that if local stressors are reduced before, during, and after bleaching events, corals are more likely to recover. Local stressors include human impacts, such as unintentionally knocking over coral while snorkeling or diving, boat anchors hitting coral, unsustainable fishing practices, and pollution from nearby watersheds. 

The State of Hawai‘i’s Department of Land and Natural Resources will introduce an initiative in October aimed at tour operators to inform their guests about good reef practices. Numerous operators, like FairWind Big Island Ocean Guides on Hawai‘i Island, are already educating people on their boats. They ask them not to stand on, sit on, or touch the reef and to use reef-safe sunscreen products. 

Worldwide, about 400 million people depend on coral reefs for work, food and protection. Hawaii is no different. Yet every single reef could be gone or threatened by global heating and ocean heatwaves, especially if they become an annual event.

Sept. 3, 2019

Citizen scientists give first reports of widespread coral bleaching events across Hawaiian Islands

On Aug.23, after the Hawaii Gov. David Y. Ige’s office issued a plea for help dealing with a pending widespread and severe coral bleaching event during an ocean heatwave, early efforts have been focused on informing the community of how they can best help save the reefs.

Through word of mouth and social media efforts, the Hawaii state government, local tourism offices and dive and surf shops have been spreading the word to its citizen scientists of being the extra eyes on the reef to help state and federal managers monitor and best respond to the ongoing bleaching event.

“During the past eight days since the Governor’s Office announcement, there have been 62 reports of bleaching events coming from our citizen scientists,” said Greg Asner, who directs Arizona State University’s Center for Global Discovery and Conservation Science

A map showing reports of coral bleaching events

This past week, Asner has been in a series of emergency meetings with state and federal officials to help mitigate the harmful effects of the looming coral reef crisis.

ASU helped launch a citizen science and satellite tracking effort for sharing information and reporting coral bleaching. Quickly, Asner’s team created, a partnership between the Center for Global Discovery and Conservation Science (Twitter @ASU_GDCS), NOAA (@NOAA) and Hawaii's Division of Aquatic Resources (DAR), Planet (@planetlabs) and Allen Coral Atlas (@AllenCoralAtlas) to inform about coral reef bleaching in Hawaii and to galvanize action.

To help map incoming reports, the website offers an easy interactive tool for citizens to report the location and severity of bleaching events.

The map shows reports of moderate to severe bleaching already underway from out west on Kauai to the Big Island. Responding to these reports, GDCS scientists like Robin Martin and Patrick Gartrell have been measuring living and dying coral in preparation for the ocean heatwave (see:

The latest temperature update from NOAA offer little solace for relief for the coral reefs, as sea surface temperatures continue to rise toward the levels found during the worst mass bleaching event in 2015 (see:

For Hawaii’s communities, people are asked to be ready to get out to the reefs and help by reporting any bleaching Please participate and spread the word. #coralbleaching2019 @asuresearch

On Twitter, please follow @hawaiicoral_org for updates on ASU's work with Hawaii's Division of Aquatic Resources & @NOAA monitoring coral reef health during the current ocean heatwave in #Hawaii.

Aug. 23, 2019

July ended with the hottest recorded average temperature since people have been making daily readings. With the warming, climate change is ensured. A huge chunk of Greenland has melted, Arctic seas have opened, and the diversity of life on Earth may be threatened

Now, the effects are spreading across the Hawaiian Islands, with some of the most diverse and abundant life under peril due to a massive coral bleaching event underway.

According to NOAA scientist Jamison Gove, "Ocean temperatures are extremely warm right now across Hawaii, about 3°F warmer than what we typically experience in mid-August. If the ocean continues to warm even further as projected, we are likely to witness severe and widespread coral bleaching across the islands."

Ocean heatwave shows warming temperatures

This event is coming a mere four years after the unprecedented bleaching events of 2014 and 2015. Just as the Hawaiian coral reefs were showing remarkable resiliency and making a recovery, they are faced with yet another event.

Coral bleaching is a change from normal coloration of browns, yellows and greens to a nearly white color. This change occurs when corals are stressed by environmental changes, especially temperature increases. Although corals can recover from moderate levels of heat, if it is prolonged, they will die.

But scientists say that reducing secondary stress on corals during these ocean heat waves can improve the chances of coral survival.

According to Division of Aquatic Resources (DAR) administrator Brian Neilson, “We know this bleaching event is coming, and it’s probably going to be worse than the one we experienced a couple of years ago, when West Hawaii experienced a 50% mortality rate and Maui experience 20-30% mortality rates on DAR fixed monitoring sites. We’re asking for everyone’s help in trying to be proactive and minimize any additional stress put on coral.”

As part of its sustainability commitment to help preserve life on Earth, Arizona State University is leading the effort to help Hawaiians save the reefs by providing real-time monitoring in support of DAR's efforts. 

 "The work that the team is doing here, in cooperation with DAR, is the first time on planet Earth that we are doing real-time monitoring of a bleaching event," said Greg Asner, who directs the new ASU Center for Global Discovery and Conservation Science.

Their suite of technology has extensively mapped the state of coral reef health before the warming event. Now, their heroic efforts will monitor the warming ocean’s impact on coral bleaching through space satellite imaging, 3D laser mapping from the air and sensors sunken on the ocean floor.

"The sea surface-temperature alert already went up, and this is the highest temperature ever recorded in Hawaii," Asner said. “But bleaching is not death, so there is still a chance to save the coral reefs.” 

Asner mentions that what ultimately kills coral are algae, who thrive and multiply with the higher temperatures, gobbling up all the surrounding oxygen and snuffing out coral and ocean life.

DAR is working with the Hawaiian community on simple ways that they can specifically help:

• Avoid touching the reef while diving, snorkeling or swimming.

• Do not stand or rest on corals.

• Use sunscreens with no oxybenzone or octinoxate.

• Boaters should use mooring buoys, or anchor only in sand areas and keep anchor chains off the reef.

• Fishers should reduce or stop their take of herbivores, such as parrotfish, surgeonfish and sea urchins. Herbivores clear reefs of algae, which overgrow and kill corals during bleaching events.

• Taking extra precaution to prevent contaminants from getting to the ocean like dirt from neighboring earthwork, chemical pollution from fertilizers, and soaps and detergents getting to storm drains.

Together, through state agencies, ASU research and the community, they may help stem the tide on coral bleaching.

A bleached coral from the unprecedented bleaching events of 2014 and 2015. Just as the Hawaiian coral reefs were showing remarkable resiliency and making a recovery, they are faced with yet another event in 2019.