Half Of All Coral Reefs Are Dead. A Maui ‘Super Reef’ Offers Hope.

Maui artist Michiko Smith grew up in Lahaina. After a deadly wildfire leveled much of her coastal town and destroyed her apartment, Smith took stock and decided to reprioritize her life.

The 30-year-old continues to make art from marine debris, mainly “ghost nets” cast adrift from fishing vessels. But making her beloved West Maui more resilient to climate-fueled disasters has become Smith’s obsession.

After enrolling in a marine studies program at University of Hawaii Maui College, she discovered the Super Reefs project. A partnership of Stanford University, Woods Hole Oceanographic Institute and The Nature Conservancy, the research aims to determine why some coral reefs are resilient to ocean warming, perhaps able to survive climate change.

Nearly half of the world’s coral reefs have died since the 1950s. Besides ocean heat, reefs face threats from overfishing, polluted run-off, ocean acidification and other human-caused stressors.

But there’s hope. And it may lie at Olowalu, just 4 miles from the epicenter of the August 2023 Maui fire that killed 102 people. There, a thriving reef larger than New York’s Central Park is drawing attention from some of the world’s top scientists.

They’re seeking answers to some basic questions: Is Olowalu a super reef and, if so, how do it and others like it survive marine heat waves that spell mass extinction for others? If it’s something special about their DNA, can that be replicated and transported to dying reefs to help them recover?

Because conservation often starts at the local level, the super reef investigators are training volunteers like Smith on the protocols and experiments that could unlock the mystery of why and where super reefs exist.

“Knowing that what I’m doing on the land is helping out the reef, it feels good.”

Michiko Smith, Maui artist

They’re keeping costs down with low-tech tools, including Igloo ice chests from Walmart that serve as makeshift coral tanks.

“We’re kind of working from the ground up rather than like a top-down approach,” said Tiara Stark, program manager with The Nature Conservancy, “just really working with the community and making sure their voices are heard.”

Smith and other volunteers spent much of last summer running heat experiments, extracting DNA, photographing coral responses and documenting data. The experience opened up a new job for Smith with Kipuka Olowalu, a nonprofit that restores native plants, removes invasive species and incorporates traditional Hawaiian principles in land stewardship at Olowalu Valley.

The two pursuits are related. The goal of restoring the land scarred by cattle grazing and wildfires is to prevent sediment from flowing down the valley and onto the reef.

Smith hopes that those efforts, combined with a $10 million ridge-to-reef restoration project led by the Hawaii Department of Land and Natural Resources, will improve West Maui’s ecological health and resilience to future fires.

“Knowing that what I’m doing on the land is helping out the reef,” she said, “it feels good.”

Olowalu Reef: An Underwater Eden

The Olowalu reef is one of Hawaii’s oldest and most iconic.

As the Earth’s largest living structure, corals are fragile ecosystems protected under state law. It’s illegal to damage or remove coral and restoration work can only be conducted under a permit from the Department of Land and Natural Resources.

Corals hold deep cultural and spiritual significance in Hawaii. The Hawaiian creation chant, or Kumulipo, says all life began with a coral polyp that emerged from the darkest depth of the sea. Hawaiians view coral as an akua, or supernatural being, and believe that without coral, life on Earth could not exist.

Hawaii’s subtropical waters support up to 80 species of coral. At Olowalu, the most common are cauliflower, finger, rice and massive lobed coral. In shades of lemon chiffon, green tea, pastel pink and khaki, coral colonies attract copious marine life and oceangoers.

At some 1,000 acres, the Olowalu reef is thought to foster the largest population of manta rays in the nation as well as the most fish biomass — fish measured by weight — in West Maui, according to The Nature Conservancy.

Olowalu also functions as a nursery for black tip reef sharks and a cleaning station for manta rays and sea turtles.

The underwater Eden sheltered from strong trade winds and big ocean swells offers tourists and locals some of Hawaii’s best snorkeling and diving. Oceangoers are treated to rare coral formations, some more than 500 years old, and tropical fish found only in Hawaii, including bluestripe butterflyfish and Hawaiian cleaner wrasse.

The reef caught the attention of Mission Blue, a nonprofit founded by legendary oceanographer Sylvia Earle in 2017. Earle thought so highly of Olowalu that her organization designated it a Mission Blue Hope Spot, a place critical to ocean health.

Because of the large number of sea turtles it attracts, Olowalu often is called Turtle Reef. Its other name is Mother Reef of Maui Nui because it’s a primary source of coral larvae for reefs near Lanai, Molokai and other parts of Maui island.

During the spawning season, currents and waves carry the free-floating larvae, called planulae, for miles, where they create new coral colonies.

That so-called larval connectivity is a key attribute of super reefs.

The reef’s ecological, economic and cultural significance, and the threats from ocean warming and sediment from fire-scarred landscapes inland, were what motivated Nature Conservancy staff and West Maui residents to ask the Super Reefs team to consider Olowalu for its global research project.

After some initial research and discussion, the scientists agreed to take a look.

Reefs Face Unique Challenges Amid Climate Change

The Super Reef project at Olowalu is timely.

The University of Hawaii found in a 2022 study that almost all of the world’s coral reefs will face “unsuitable conditions” by 2055, likely leading to major die-offs. Some scientists say that coral cover in parts of Hawaii has declined by 60% in recent decades.

Smith has seen the decline with her own eyes.

“When I was growing up, it was really vibrant,” Smith said, describing the reefs of West Maui. Now, she said, there are fewer herbivore fish, more reef-smothering algae and more dead zones.

Beyond the usual stressors, West Maui reefs face a unique challenge.

The Lahaina fire left behind a burn scar spanning five acres. Scientists, government officials and ocean users feared rains would wash toxins from the fire into the ocean, polluting nearshore waters, poisoning fish and harming the reef.

The Environmental Protection Agency applied a soil stabilizer to keep fire residue in place until the U.S. Army Corps of Engineers could scrape the burn zone clean.

Scientists at UH Maui College, UH Manoa, U.S. Geological Survey, Hawaii Sea Grant and local organizations are all studying how the fire altered the coastal environment. Some early results are promising but much remains unknown.

It was the fire and its aftermath that jolted Smith into action. She wanted to help prevent another catastrophe. When one of her Maui College professors told her about the Super Reef project, she jumped at the chance to participate.

Before long, she found herself setting up makeshift tanks under the direction of Courtney Klepac, a postdoctoral scholar at Stanford who is leading the Olowalu portion of Super Reefs.

Klepac relies on sophisticated computer programs designed by Woods Hole Oceanographic Institute to decide where to look for super reefs.

The 3D computer modeling tracks and predicts ocean temperatures, currents, wind and wave action, larval spawning and distribution, and other data points.

“Basically what the model is doing is running some physics equations about what we know about how water moves,” said Calvin Quigley, a Woods Hole scientist. “It’s running physics equations over and over.”

The models yield ultrafine-scale information about salinity, temperature, density and velocity and other aspects of an ocean location that are relevant to coral reefs. It helps determine where to focus the super reef research.

After Olowalu rose to the top of the list of new super reef candidates, Klepac enlisted the help of The Nature Conservancy and Maui Nui Marine Resource Council to find people like Smith.

An important goal of the Super Reef project is to develop a trained local workforce that can continue the research and advocate for reef protection.

Unlike in other remote places where super reefs have been found, in Belize, Palau and the Marshall Islands, the scientists were able to easily recruit Maui residents.

They proved invaluable, Klepac said.

“They helped us the entire time,” Klepac said in a recent video presentation for Maui Nui Marine Resource Council. “They were wonderful humans to work with.”

Investigating Coral Bleaching

With coral samples from eight sites in West Maui in hand, Klepac trained Smith and the other volunteers how to set up the Igloo coolers and get to work.

“We can literally work anywhere. All we need is access to seawater and a source of power,” she said.

They set up the coolers inside the Maui Ocean Center Marine Institute in Maalaea, which runs its own coral research program and operates a sea turtle hospital.

Five coolers were outfitted with heaters, pumps and gauges to run heat stress tests. The other five served as control tanks, holding seawater at regular ocean temperature.

Smith learned to rate how the fragments from four coral species responded to the temperature variations. A score of one meant the coral did not react while a five equaled severe bleaching.

“We can literally work anywhere. All we need is access to seawater and a source of power.”

Courtney Klepac, postdoctoral scholar at Stanford University

Bleaching occurs when corals — which are animals — expel their microscopic algae, or zooxanthellae. A primary food source, the algae also give the corals their unique colors. When stressed, the animals shed the colorful zooxanthellae that lives in their tissue.

Bleaching doesn’t always automatically spell instant death for corals. They can survive. But the more times they bleach, or if the heatwave causing the bleaching is hot or long enough, the more likely they are to perish.

The heat tests Smith did replicated those stressful scenarios.

Key To “Super Reef” Designation Is Resilience

Maui suffered two major marine heatwaves, in 2015 and 2019, that resulted in significant bleaching at Olowalu reef. Fortunately, the events were spread out enough that the corals have been able to recover and rebuild.

The combination of future heat waves alongside other human-driven stressors, add a sense of urgency to understand and protect Olowalu, and maybe use its resiliency and robust genes elsewhere.

If Olowalu makes the super reef cut, next steps would likely include engaging the local community to ask the state Department of Land and Natural Resources to protect the area.

“Regardless of what… the super reef project finds, we’ve already identified it as critically important.”

Russell Sparks, aquatic biologist and education specialist with DLNR’s Division of Aquatic Resources.

That could take a variety of forms but activities such as fishing can be limited or even banned in other types of marine protected areas in Hawaii.

“It is not up to us to decide which reef gets protection,” Klepac said in an email. “Agencies consider multiple factors, such as commercial and recreational use, fish stock, algal and invertebrate abundance, in addition to our results when making decisions.”

Because super reef designation is not binding, government agencies can simply ignore the research findings entirely, she said.

That’s not likely to happen.

“Regardless of what this project, the super reef project, finds, we’ve already identified it as critically important,” said Russell Sparks, aquatic biologist and education specialist with DLNR’s Division of Aquatic Resources. “We’ve identified some of the key threats and we’re working with the community to address them.”

The $10 million ridge-to-reef restoration project that DLNR expects to begin soon will benefit Olowalu, and Kelpac said she hopes the super reef test results “can assist with how big that protected area should be.”

With funding from NOAA, the Division of Forestry and Wildlife will rehabilitate the watershed to prevent sediments from washing into the ocean.

That includes controlling feral pigs, goats and axis deer with fencing and ultimately removing them. It also involves reforestation with native species, wetlands restoration, construction and maintenance of firebreaks and vegetative corridors known as “greenbreaks,” and creating a sediment basin to capture run-off.

The work, announced in July, is expected to take three years.

Jill Wirt, program manager with Maui Nui Marine Resource Council, is hopeful that what’s learned at Olowalu can be adapted for use in places like South Maui where reefs are threatened by other damaging factors, including sedimentation, pollution and development.

“You find heat resistant coral but that’s only one side of the story,” Wirt said.

Klepac and the Stanford team left behind the equipment they used for the Olowalu experiments so it could be deployed on coral samples from other Maui reefs. Using it to test coral resilience to other threats could be a game changer.

Maui has ongoing problems with reef-killing discharges from wastewater injection wells, for example, which continue despite years of litigation.

Adapting the science would require additional equipment, so it would be more expensive, Klepac said in her email, but it is possible.

“I always love to suggest that the system can be used on more than just coral and/or more than just heat,” she wrote.

Today Klepac and her Stanford team are in the midst of analyzing the data collected last summer, which is laid out in detailed spreadsheets with charts and scores. The team is crunching bleaching rates from samples of four coral species taken from eight extraction sites that stretch from Honolua Bay — north of the Kaanapali tourist district — down to Coral Gardens, south of Olowalu.

Early signs are pointing to Olowalu as the next designated super reef.

“A lot of our Olowalu sites are generally pretty tough,” Klepac said. “So that’s quite exciting.”

This series is part of the Pulitzer Center’s nationwide Connected Coastlines reporting initiative.

Civil Beat’s coverage of environmental issues on Maui is supported by grants from the Center for Disaster Philanthropy and the Hawaii Wildfires Recovery Fund, the Knight Foundation and the Doris Duke Foundation.