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As the world’s climate changes, the rate of ocean warming is accelerating at an unprecedented rate, sea levels are rising and many ocean species are dying out. However, one species that is not feeling the heat, but is, in fact, thriving in warm waters spurred on by the climate crisis, is the jellyfish. On World Jellyfish Day, which every year falls on November 3, here are some fascinating facts about this fascinating species.

Global climate change has been causing sustained warming of the oceans since 1970. It has likely been happening at an increasingly rapid rate since 1993, and with no reduction in intensity, according to the most recent report by the Intergovernmental Panel for Climate Change (IPCC). Despite this, the jellyfish is thriving in the fertiliser-rich, deoxygenated warm ocean waters. 

Jellyfish Facts

Putting a number on jellyfish populations is difficult due to a lack of quantitative records. However, a study showed that jellyfish populations have increased in at least 68 ecosystems around the world since 1950 and “are one of the few groups of organisms that may benefit from the continued anthropogenic impacts on the world’s biosphere.” 

Jellyfish populations fluctuate in blooming cycles naturally. However, the recent growth  is correlated with man-made changes to the environment. Blooms of the giant jellyfish (Nemopilema nomurai), which have historically happened in Japan once every 40 or so years, have become a yearly occurrence since the early 2000s. The animals cause many problems, such as clogging fishing nets, affecting tourism in places that rely heavily on its oceans, stinging people, killing fish by lodging within gills and clogging cooling screens in power plants, amongst others. In June 2018, over 1,000 people were stung by jellyfish in a single week in Florida. 

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Jellyfish are also particularly dangerous near nuclear coastal power plants. To prevent a disaster whereby a swarm of jellies block an underwater cooling system, costly shut-downs, such as in Torness (UK, 2011), or Oskarshamn (Sweden, 2013) are necessary. 

The gelatinous animals owe their explosion in numbers to a variety of factors, as outlined in a report by the Union of Concerned Scientists and below.

Jellyfish Thriving in Warm Waters

The warm waters are forcing tropical coral reefs to seek more temperate regions, a migration that has been happening at a rate of 8.7 miles per year since the 1930s. Migrating coral makes way for other marine species – including jellyfish – to extend their habitable territory. This throws the local ecosystems off-balance as jellyfish join the competition for zooplankton, as well as hinder the lives of fish by eating their eggs, larvae and juveniles, according to the Earth Institute of the University of Colombia. Increases in populations of non-indigenous species are possibly the most damaging of all.  

Additionally, oceans are dumping grounds for carbon, which further aid jellyfish. IPCC models show that as the concentration of atmospheric CO2 since the beginning of the century has increased, so has the oceanic absorption that has led to warm waters for jellyfish. It is estimated that within this time frame, oceans have absorbed 20-30% of total man-made emissions globally.

The rise of CO2 in the atmosphere means that more CO2 gets absorbed into seawater. This carbon reacts with water molecules to form carbonic acid, which then breaks down into hydrogen and bicarbonate. The presence of all these hydrogen ions this reaction creates causes the water to become more acidic. Gases dissolve more readily in cooler waters and so acidification is more pronounced in the Arctic and Southern oceans. This acidity inhibits coral growth and causes reefs to die off in a process called ‘coral bleaching,’ allowing jellyfish to roam and multiply freely.

Anthropogenic influences significantly impact jellyfish populations. Fertiliser and effluent sewage from land cause oversaturation of water with nutrients, particularly around coastal estuaries – a process known as eutrophication – enabling excessive algal growth. Decaying algae depletes water of oxygen. Jellyfish are able to tolerate low concentrations of oxygen and with plentiful food, they continue to multiply, while other fish suffocate and die. Additionally, coastal development, the building of docks, boats anchored in harbours and underwater infrastructure provide perfect surfaces for breeding jellyfish to attach to in their polyp stage.

Finally, the overfishing of species which prey on jellyfish, such as tuna and sea turtles, means that jellyfish are able to breed undeterred by predators. According to Dr Callum Roberts, a marine biologist and author of the seminal book “The Ocean of Life,” humans take 50% more fish than thought – “a staggering total of about 130 million tonnes a year.” He explains that the issue of fishery mismanagement and the release of misleading statistics can lead us to circumstances ‘beyond our capacity to cope.’ 

Another aspect spurring on the jellyfish’s population growth is the fact that at least five known species are effectively immortal. 

The phenomenon was first observed in Turritopsis dohrnii, the ‘immortal jellyfish.’ Not unlike the mythical phoenix, from the dead body of a jellyfish springs a new one into life. 

Dr Lisa-ann Gershwin, director of the Marine Stinger Advisory Service in Tasmania and jellyfish researcher, explains on a BBC Earth podcast episode

“When Turritopsis dies its body begins to decay, as it would, but then the cells reaggregate into polyps – it skips to the alternate part of its life cycle, the earlier life stage. These little polyps keep cloning and they can cover an entire dock in a matter of few days! Some types can form whole ‘shrubs’ and when the conditions are right they bloom in vast numbers like flowers and ‘bud off’ baby jellyfish.”

The more common moon jelly has also been shown to defy death. Observing the same ability in both is a surprising, complex and hopeful discovery. 

With the rapid expansion of these populations, scientists and policymakers are brainstorming ways of making the animals useful. The GoJelly project proposes employing the creatures’ ability to use their mucus to bind microplastic. The researchers intend to develop a microplastics filter to be used in wastewater treatment plans and in factories where microplastic is produced, which could help prevent much of these particles from getting into marine ecosystems and harming wildlife further.  

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Coral reefs are facing events of severe bleaching and physical destruction due to human coastal development, as well as the effects of unmanaged tourism, including anchoring, fish feeding, marine litter and diver contact. Their resilience depends on effective management. We take a look at how resilience-based management is being adopted in major reef regions around the world to secure the foundations for sustainable development and adapt to global warming.

The Importance of Coral Reefs 

Coral reefs are among the most valuable ecosystems on the planet. Besides containing one of the most biodiverse ecosystems on earth, coral reefs protect coastlines from the damaging effects of wave action and tropical storms, are a source of nitrogen and other nutrients for marine food chains, assist in nitrogen and carbon fixing and are a source of income for millions of people around the world. They also play an important role in generating the sand and rubble that maintain islands and cays. 

Resilience-based management plans focus on the processes essential to coral’s ability to survive the impacts of global warming. Key strategies to include in these plans include identifying and protecting reef areas that are naturally resistant to climate change impacts, reducing sources of pollution that increase sensitivity of corals or increase their susceptibility to disease, preventing damage to reefs through poor boating practices or destructive fishing, preventing overfishing of herbivorous fish and restoring places of ecological priority following stress events. 

The Threats to Coral Reefs

Macroalgae and herbivorous fish populations should also be closely monitored. Macroalgae, such as seaweed, is known to poison corals and reduce or halt the settlement and survival of juvenile corals. Herbivorous fish, such as parrotfish and surgeonfish, reduce or eliminate macroalgae from coral reefs and facilitate the growth of reef corals. Increasing the diversity of herbivorous fish and other functional fish groups can indirectly drive coral reef recovery. 

Studying the trajectory of algal growth over time allows researchers to determine the success or failure of strategies to manage herbivory or other factors that contribute to algal growth and the success of reef corals. 

While coral animals are incredibly fragile (just one knock from the fin of a careless diver or snorkeller could cause coral breakage that takes many months, or even years, to recover from), they have proven to be resilient; healthy coral that is free from stress has a better chance of recovery, whereas coral that experiences stress will recover slowly, if at all. 

For example, while coral cover in Bonaire, an island in the Caribbean, suffered extensive damage following a hurricane and a coral bleaching event, corals have recovered to pre-bleaching levels less than a decade later due to effective resilience management.

Sustainable Management of Coral Reefs

Several factors contributed to its management success. The island developed its diving and hotel industries early and they have become Bonaire’s economic engine, above industries such as fishing. Additionally, the most economically valued fishing targeted fish other than coral reef dwelling fish. These factors mean that relatively few people in Bonaire depend on reef fish for food, allowing the fish to thrive. 

While addressing global threats poses a huge challenge, there are many things that can be done on a grassroots level. Therefore, focusing on reducing these direct threats- which can make corals more vulnerable to larger-scale stressors- is key. 

The Reef-World Foundation is a conservation NGO aiming to improve environmental practices across the marine tourism industry. The charity coordinates the Green Fins initiative globally in partnership with the UN Environment Programme. Green Fins focuses on helping diving and snorkelling businesses, as well as individual tourists, reduce their negative impact on coral reefs and other marine environments and provides the only internationally recognised environmental standards for diving and snorkelling.

Green Fins works to measurably reduce direct threats to coral reefs such as diver contact, anchoring, fish feeding, marine litter and chemical discharge, amongst others. Not only does this type of well-managed tourism protect coral reefs- leaving them healthier, more resilient to climate change impacts and more effective at their ecosystem services- but also presents an economic opportunity, creating food and sustainable employment for millions of people around the world. 

Sam Craven, Programmes Manager at Reef-World, has been involved in the implementation of the initiative for many years. Achieving conservation impact, for Sam and her team, is all about collaboration; whether that be with governments, marine tourism operators or individual dive guides and tourists. She explains: “More often than not, marine conservation is less about ‘saving the sea’ and more about managing people’s impact on the sea.” She continues: “Science alone doesn’t change the world; it’s how you use it that counts.” 

Climate change-related coral mortality is unavoidable, but local management actions can improve conditions for regrowth and rehabilitation. Yet, while management schemes should be seen as essential components of mitigating coral reef mortality, major reductions in global greenhouse gas emissions is vital for securing a sustainable future for coral reefs and those who depend on them. 

This is Part One of “Improving the Resilience of Coral Reefs.” Read Part Two here.

The US has proposed to protect 12 critical coral species in the Caribbean and Pacific Ocean, which- if implemented- would protect nearly 16 000 sq km of critical coral habitat.

Coral reefs are some of the most biodiverse ecosystems in the world, and they also serve as economic lifelines to millions around the world. According to the National Oceanic and Atmospheric Administration (NOAA), their annual economic value in the US alone exceeds USD$3 billion. 

What is Happening?

While Andrew Baker, a marine biologist with the University of Miami who specialises in the impact of climate change on coral reefs, praises the proposed protections, he calls them a “necessary but insufficient step” for helping coral species. He says, “The critical habitat designation in and of itself isn’t going to protect corals from climate change directly, but it does prevent certain potentially destructive activities from occurring in these habitats,” he said.

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In 2019, The Center for Biological Diversity sued the Trump administration for its failure to implement habitat protections for these species five years after the corals were initially listed under the Endangered Species Act in 2014. Threatened species are supposed to receive habitat protections at the same time they are listed. 

Featured image by: Flickr 

Corals are well-known for their captivating colours due to microscopic algae inhabitants. However, some have been seen glowing, which is unusual. Researchers have sought to understand the reason behind this glowing in a new study, which has found that it plays a significant role in maintaining the symbiotic relationship between corals and its zooxanthellae. How do these fluorescent pigments help corals to adapt to climate change? 


Coral reefs are one of the most productive ecosystems on the planet, and the primary production that occurs through photosynthesis is established by the mutualistic relationship between the zooxanthellae and corals. Zooxanthellae is a type of algae, known as dinoflagellates, that live symbiotically with corals. Zooxanthellae carry out photosynthesis to provide nutrients to corals, while corals offer shelter to the algae.

Fluorescent Pigments Act as a Protective Shield

In surface water, sunlight is a key driver for the photosynthetic primary production, where zooxanthellae undergo photosynthesis. Yet, high energy wavelengths such as UV rays may cause photoinhibition and photodamage to the algae. Previous studies have found that corals possess types of protein with fluorescent pigments to counteract the environmental stress induced by sunlight by absorbing or diverging the damaging wavelengths and converting them into lower-energy light such as visible and infra-red light. A similar mechanism can also be found in terrestrial plants such as blueberries, which contains a pigment called anthocyanins, to reduce light stress when exposed to sunlight. 

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Why are Corals Glowing in the Deep Sea? 

Apart from the surface water, corals also display psychedelic colours in the deep-sea region, where there is little or no sunlight. A recent study found evidence that corals use fluorescence to increase its survival in the deep-sea environment, which serve a different purpose than that of corals living in shallow water. 

Given that the deep sea environment is dominated by blue light, deep-sea corals are equipped with a specific protein, known as photoconvertible red fluorescent protein, which converts the blue light into longer wavelength (i.e. orange-red light). Orange-red wavelengths help enhance light penetration and reflection, and allow even distribution of light within the coral tissue and its skeleton, thus increasing the productivity of zooxanthellae living in deeper coral tissue.  

Studies have also discovered that more of the red fluorescent proteins in corals was found in the lower water column, demonstrating the ecological significance of the red fluorescent protein to help corals better adapt to the deep-sea region.

The glowing colour may also appear in cases where coral bleaching occurs. Given that coral symbionts are sensitive to heat and light stress, corals who suffer from these stressors would result in symbiont expulsion. Experimental studies demonstrated that corals have developed a self-regulating mechanism, known as an optical feedback loop, which is triggered by the increased internal backscattering light from the coral skeleton due to reducing symbiont density in coral tissue. Corals can enhance photoprotection through increasing internal light absorption by protein pigments to lower the light stress, which in turn helps facilitate the recolonisation of symbionts on bleached coral tissue. 

Scientists have just provided a new explanation as to why corals are being seen glowing in deep-sea environments, showing that it does so to adapt to environmental stresses. The study also emphasises how little we know about coral reefs and marine ecosystems. Coral reefs have long been known to be the most productive and biodiverse ecosystem on Earth and have recently been found to be a new reservoir for medicine discovery in recent years. 

In view of the increasing rate of coral bleaching due to the climate crisis, effective actions will need to be taken collaboratively by government and international organisations to prevent further degradation of environmental quality. 


Like a mermaid on an underwater picnic, she floats gently in the current as slivers of sunlight reveal a garden of corals in the Golfo Dulce, in southern Costa Rica. Holding a basket filled with round, spiked corals, she collects one last specimen, then begins her ascent. As she breaks the surface, Socorro Avila, a research assistant who grew up on this gulf, joins Joanie Kleypas and Tatiana Villalobos – two more mermaids – and they swim towards the boat that idles nearby.

The three scientists deliver their bounty, passing round, spiked corals into the waiting boat. Handling each piece requires patience — some trail along a clear fishing line, while others twist into woven strands of a rope. As they untangle each precious item, the corals’ branches jostle, tinkling like porcelain dolls colliding. The team board the boat, doff their scuba gear, and head further into the gulf — one step closer to understanding these mysterious species.

For three years, this team that goes by the name of Raising Coral Costa Rica has been snapping off coral pieces from existing reefs to grow them in an underwater nursery. Months later, the team moves the nursery-grown corals and attaches them to skeleton-like structures that once were living, thriving reefs in the Golfo Dulce. Kleypas, a scientist at the National Center for Atmospheric Research in Colorado, has spent 30 years spent studying coral reefs, while Villalobos, along with a handful of other researchers involved in the project, are a part of the University of Costa Rica’s ocean and freshwater science division, or CIMAR.

The team is using tested techniques and experimental ideas to grow coral and revive ancient reefs in the Golfo Dulce, an underwater oasis in the Eastern Tropical Pacific Ocean, where coral reefs have been historically understudied. By contrast, researchers have studied corals of the Caribbean Ocean and the Great Barrier Reef far more extensively. “These corals have been ignored, mainly because they don’t form big, huge reefs,” Kleypas said. But the species in this part of the Pacific support high levels of biodiversity, behaving similarly to the well-studied Caribbean reefs, but with fewer corals overall, she added.

Their findings are helping to restore local ecosystems, and could help researchers who hope to revive reefs in nearby countries. The species of the Golfo Dulce, when compared to a lot of the world’s reefs, may hold extraordinary clues about resilience to changing ocean conditions. Each day, the ocean’s tide ebbs and flows in the gulf, which raises and lowers the temperature, acidity, and salinity regularly. Because these reefs are exposed to constant fluctuations, researchers are curious whether they may be better suited to withstand changing ocean conditions than the corals that live in the ocean, without daily fluctuating conditions.

As the race to save our oceans against a changing climate accelerates around the world, knowing how to rebuild one of its foundational components, coral reefs, may be one way that scientists can help them survive in a warming world.

“Sweet Water” No More

Spanish explorers led by Christopher Columbus landed their ships on the western coast of Costa Rica in the early 1500s. In Spanish, Golfo Dulce translates to “sweet gulf,” but the early explorers in this part of Latin America used the name to refer to sweet, or fresh, water. Four large rivers — Tigre, Rincón, Esquinas and Coto-Colorado — empty into the gulf. This fresh and salty water mixture makes the gulf less salty than the ocean; the Golfo Dulce has a salinity of 28 to 34 parts per million, compared to an average of 35 parts per million in the ocean.

The gulf spans roughly 500 square miles and reaches more than 650 feet deep, making it one of the world’s few tropical fjords, a long stretch of deep water surrounded by steep shores. With its calm waters and expansive depths, Golfo Dulce is a hotspot for marine wildlife. It is the only known place where both northern and southern humpback whales migrate while calving, new invertebrates are still being discovered, and sharks, turtles and fish use these gentle waters as a temporary and permanent residence throughout the year.

Along the gulf’s shallow coastline, and on the sloping bottoms below, lie patches of ancient coral reefs — some dating back thousands of years. Decades ago, these reefs were nearly decimated by agricultural development. Chiquita Banana, part of the larger United Fruit Company, moved to the area in 1937 and began building its headquarters, as well as banana plantations. This heavily altered the tropical jungle, and dirt filled the rivers and gulf in unprecedented amounts. Development in the area continued when banana plantations were converted to plots for palm oil in the 1980s. A study between 1992 and 1996 revealed that live coral coverage on one reef in the gulf, in playa Sándalo, decreased from 29 to 17%, due to elevated amounts of erosion.

“I spent my childhood here. I did my homework, fished and swam,” said Jorge Largaespada Amador. Now 53, Amador moved to Playa Blanca, a small town on the gulf, when he was six. He recounted swimming with red snapper and sharks as they hunted nearby in the reefs.

“The reefs were alive, now they’re dead.”

Today, much of the land surrounding Golfo Dulce is protected as a national park or refuge, but only a small portion of the water is included. “About 10 percent of Piedras Blancas National Park, around 14,000 hectares total, extends into the gulf,” said Geinier Barquero Vanegas, a park ranger with MINAE SINAC, the division of the national government that manages conversation areas. In 2010, the Golfo Dulce was declared an Área Marina para la Pesca Responsable, making it the largest responsible fishing area in Central America. This declaration prevents commercial fishing boats from entering the Golfo Dulce, offering marine life in the gulf a chance to rebuild and flourish.

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costa rica corals

Coral polyps (source: Mongabay). 

“Los Corales,” the Corals

Most of the world’s reefs, including those in the Golfo Dulce, grow in shallow, tropical waters near the equator. In total, these reefs cover 284,300 square kilometers, or less than 1%, of the seafloor — and the reefs in this gulf represent a small fraction of the already thin sliver. But coral reefs build the foundation of marine ecosystems — they support over 25% of ocean life. Coral, using minerals from the seawater, build a structure for countless organisms to live. In the Golfo Dulce, little coral crabs are common tenants in the branches of the reefs, and schools of fish move through the reefs every day. Larger marine animals, like spotted eagle rays and nurse sharks, use these areas as nursery and hunting grounds.

Like New York City, filled with industrial buildings and people keeping the lights on, a coral reef is made up of animals that build the structures and algae that live inside. The algae, known as zooxanthellae, use sunlight to produce the majority of the energy needed to power the underwater cities, and the coral provides a safe haven.

When ocean conditions change, such as when water temperatures rise uncharacteristically or water clarity decreases, the two organisms that work together to build a reef fall out of sync. This off-balanced relationship causes the colorful, energy-producing organism to flee the reef, leaving behind a colorless, “bleached” coral skeleton with no substantial way of producing its own energy.

Over time, as runoff in Golfo Dulce accelerated, the corals were covered with sediment and sunlight was blocked. The algae weren’t able to produce enough energy and the corals eventually began to die. And ocean warming trends of recent history have only accelerated coral bleaching events in Golfo Dulce, and around the world.

During a massive global 2015-2016 coral bleaching event, 75% of the Golfo Dulce’s coral cover declined. But the Raising Coral research team was surprised when corals started to recover only two years later. “We got excited that they came back relatively quickly … they’re so tough,” Kleypas said. Filled with more than an inkling of hope from these hardy corals, the team is working towards establishing a process for coral restoration in the Eastern Tropical Pacific Ocean and genetic testing to define what’s behind this resilience.

Coral species as a whole have become increasingly threatened and researchers don’t know if these complex underwater communities can survive into the next century. Although we can’t necessarily halt climate change or human pressures altogether, there may be ways to lessen the impacts on coral reefs. If done right, coral reef restoration may be a way to produce climate-tolerant corals. In a world where haphazard restoration projects are springing up overnight, this team’s approach to restoration and the unique environment in Costa Rica may serve as a model for researchers racing to rebuild the world’s coral reefs.

The Team

When Joanie Kleypas was introduced to the eastern tropical Pacific waters of Costa Rica, she learned about ancient reefs that had been decimated by runoff. “I had to see them for myself,” she said. Kleypas was inspired and used funds from an award in 2011 to begin experimenting with ways to help the corals grow again. “This part of Costa Rica has a history of ecological conservation — the water quality was improving and people were starting to care about the Golfo Dulce,” Kleypas said.

Tatiana Villalobos, who grew up in the northern Alajuela Province in Costa Rica, was embarking on graduate studies at the University of Costa Rica when a mutual friend introduced her to Kleypas in 2016. Villalobos had experienced the shock of seeing a bleached coral reef in her teenage years, and knew that she had to do something to help. Together, they began a project that combined their passion for coral reefs and ties to southern Costa Rica.

The two researchers and their teammate, José Andrés Marín Moraga, who focuses on restoration in Costa Rica’s North Pacific coast, set off to the United States in 2016, to learn how to grow coral species from David Vaughan, then director of the Mote Marine Lab in Florida. Vaughan has pioneered a technique called “microfragmentation,” now used to grow corals around the world. A form of asexual reproduction, microfragmentation creates an exact genetic copy of an individual coral without female or male sex cells combining. It works by breaking off a small piece of living coral and growing it in optimal marine conditions: a steady flow of nutrients and plenty of sunlight. After spending 6 to 10 months in the nursery, the coral fragment grows as a clone of the organism from which it was harvested.

After learning the technique, Kleypas and Villalobos came back to Costa Rica. The team of Raising Coral now includes experts in coral reef ecology, social science, business, and local expertise. Avila, a lifelong resident of the land surrounding the Golfo Dulce, joined the team to help tend to the underwater nurseries each month. Finding people who grew up near these waters, who know them best and have a mutual interest in its health, was a major priority for Villalobos and Kleypas.

Before starting any work in the Golfo Dulce, Villalobos spoke with the local communities who rely on the health of the gulf. She met and interviewed nearly 200 residents, probing their knowledge of coral reefs. “It was really interesting, and at times, very frustrating,” she says. She learned that some of the local fishermen thought that the bleached corals, a brighter white color, were healthy and well, when in reality, healthy coral species of the eastern tropical Pacific have a dull, neutral coloring.

“We really needed to do our homework before we started this project,” Kleypas says. They surveyed all of the reef structures — investigating water quality, proximity to development, and ability to provide larvae to other reef structures. Ultimately, they identified two different sites, both on underwater slopes not far from the shore, that seemed most promising for restoration.

In 2017, the Raising Coral team built an underwater nursery in a shallow, calm section of the Golfo Dulce with PVC pipes, ropes, clear fishing line and empty plastic jugs used as buoys. They tied small bits of coral harvested from the gulf to the PVC structures, creating structures that looked like underwater Christmas trees with coral ornaments floating in the current.

In the beginning, things didn’t go well: about 80% of the corals growing in the nursery didn’t survive. “It was scary; we were learning as we went,” says Villalobos. Now, things have changed, after three years of trial and error, over 1,500 new coral reef pieces have grown in their nursery — some as large as a basketball. These are harvested months later and then transported and attached to deadened reef structures.

The researchers visit the newly planted corals each month, recording their growth progress and overall health. So far, about 200 corals have been planted, and of those, 70 to 80 percent appear healthy and growing. Kleypas points out that restoring coral reefs takes time, and that only if the restored reefs survive changing ocean conditions can the restoration be considered successful.

The Coral Garden

On a recent January afternoon, the team tends to its underwater garden. Villalobos and Avila use a toothbrush to carefully clean the PVC pipes, brushing away algae. Kleypas hovers in the water over a structure that resembles a raised garden bed attached to the bottom of the seafloor with ropes running its length. She is using small, sharp pliers to break apart a large piece of coral and attach each smaller piece into an unraveled section of rope. While the exact reasoning is still unknown, these newer, experimental rope gardens are producing bigger, healthier coral fragments than expected. “There’s something about the rope that they really like,” she said later. “The corals from this line nursery have been growing so fast!”

A long few days lay ahead for Avila and the team of researchers who must clean the underwater nursery, harvest and plant the larger corals and string up new, smaller pieces. Everything seems to take longer underwater, and similar to the investment required in restoration work, patience is a virtue. Much about how to get these corals to grow fast and strong enough to survive outside of the nursery remains unknown — their destiny hinges on an eventual understanding of these species and for now, luck.

Restoration projects around the world are taking off, Kleypas said. The amount of research that goes into the execution of some projects, however, seems shockingly stunted. In the 1970s, a non-profit organisation dumped two million used car tires off the coast of Fort Lauderdale, Florida, in an effort to attract more marine life to the area. Nearly 40 years later, the area was barren of any new life (or corals) and local authorities were faced with a new problem — how to remove millions of old tires from the bottom of the Atlantic Ocean.

Rebuilding for the Future

But something must be done. As ocean temperatures around the world warm as a result of climate change and human development continues nearly unabated, global coral researchers estimate that reefs may not be able to survive without active restoration. “By 2050, estimates predict that nearly all of the reefs will be threatened, with 75% facing high to critical levels,” said Jose M. Eirin-Lopez, a coral scientist at Florida International University. This means that the 500 million or so people who currently depend on reefs for food, protection or tourism income, 30 million of which are the poorest on the planet, will be affected in some way.

Meticulous, stepwise experiments may hold a key to remedy this climate change catastrophe. Villalobos is working with surrounding countries to share what’s worked and what hasn’t, in hope that it can help. El Salvador’s Pacific coast shares many of the same coral species as those found in the Golfo Dulce, and researchers are starting to take advantage of the lessons learned by Raising Coral to begin rebuilding their own reefs. Active, organized restoration is still in its planning stages, but Johanna Segovia, an associate researcher involved in coral reef management in El Salvador, sees the work of Raising Coral as pioneering and an example to follow.

Drifting Into the Sunset

As the boat engine roar subsides, we glide through the calm waters of the Golfo Dulce and the boat drifts to a stop near a large, once-thriving reef. The coastline is filled with jungle: trees, vines, an occasional set of scarlet macaws and a glimpse of dark volcanic sand. It’s time to give Avila’s recently-harvested corals a new home.

Villalobos, Kleypas, and Avila slip into the water and begin working to attach the new corals to the ancient reef structure. They hammer a large nail into a section of the reef and use a plastic zip tie to attach each coral ornament to its stake. Even underwater, the distinct tinkling sound of a hammer hitting a nail can be heard. The corals grown in the pieces of rope are left in the twining and attached at either end to the reef structure, swaying like a clothesline in the ocean current.

A symphony of cicadas blares from the shores as the sun begins to set and the Raising Coral crew wraps up their day in the field. The mood oscillates between excitement of what’s ahead and a calm quiet. It was a productive day.

“It’s exhausting but we’re rewarded with the fact that the corals want to grow,” Kleypas said. “As long as they don’t give up, we won’t.”

Featured image by: Mongabay

This article was originally published on Mongabay, written by Ashleigh Papp, and is republished here as part of an editorial partnership with Earth.Org.

Researchers have found a new large, detached coral reef, measuring more than 500 metres in height, in the Great Barrier Reef Marine Park in Australia. This is the eighth known detached coral reef in the area, and the first to be discovered in the past 120 years.

Scientists aboard the RV Folker made the discovery while mapping the seafloor off the coast of far north Queensland state, according to the Schmidt Ocean Institute, who facilitated the expedition. The more than 500m tall reef is about one-and-a-half times as tall as the Eiffel Tower and three-tenths as high as the Empire State Building. 

Why Does This Matter?

Robin Beaman, the expedition leader and a marine geologist at James Cook University, told Mongabay, “It’s exciting that we can still find such unusually tall … reefs in the Great Barrier Reef Marine Park. People have been mapping the Great Barrier Reef since 1770 when James Cook first sailed here. Since then, we have been progressively mapping the shallower coral reefs with technologies as advanced as airborne lidar bathymetry. But it still takes a modern multibeam-sonar equipped vessel, like the Schmidt Ocean Institute’s RV Falkor, to look in the right place and then do the 100% systematic mapping required in the deeper and more remote waters of the Great Barrier Reef Marine Park, to reveal such surprising discoveries.”

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The newly-discovered reef is about 1.5 km wide at its base, rising up to 500 m, the shallowest depth being around 40 m below sea level. It is entirely separate from the Great Barrier Reef’s main shelf edge. 

To explore the reef, the team deployed a remotely operated vehicle, the ROV SuBastian, which started at the base of the reef and worked its way up, capturing the entire process and collecting biological samples. 

Excitingly, marine life was found all the way up the reef, but near the summit where waters are warmer and submit, there was a “thriving” shallow coral reef ecosystem, according to the researchers. 

In more good news, the newly-discovered reef seemed to be mostly intact, unaffected by recent bleaching events that have plagued large areas of the northern section of the park.

The discovery of this new coral reef adds to a year of underwater discoveries by the institute. In April, scientists discovered the longest recorded sea creature–a 45m siphonophore in Ningaloo Canyon, plus up to 30 new species. In August, scientists discovered five undescribed species of black coral and sponges and recorded Australia’s first observation of scorpionfish in the Coral Sea and Great Barrier Reef Marine Parks. Finally, in February, deep sea coral gardens and graveyards in Bremer Canyon Marine Park were discovered. 

Featured image by: Schmidt Ocean Institute

The climate system is holistic, meaning that in the current climate crisis, the issue of global temperature increase causes other problems, such as ocean acidification, biodiversity loss, and negative mass balance of glaciers. A concern of climate scientists is the impact that ocean warming has on ocean ecosystems, especially ones of high biodiversity value, such as coral reefs. A less observed area of coral reefs affected by ocean warming is that in the Maldives. For an island that revolves heavily around the health of its coral reefs, how can the Maldives protect them from the effects of the climate crisis?

Coral reefs in the Maldives are subjected to climatic and anthropogenic pressures. Anthropogenic pressures come in the form of overfishing, tourism activities such as diving, poor waste management systems on certain “community islands” – islands that are primarily residential and not used for tourism –  as well as dredging, land reclamation and beach nourishment (a process in which sand lost from wave deposition is replaced from other sources), which are done extensively in the Maldives according to the Maldives Underwater Initiative (MUI), a private advocacy group based at a resort/ research centre in Laamu.

In terms of climate, ocean warming is the main pressure on the local reef systems. The ocean acts as a “sink”- a natural source, such as oceans, peatlands or forests, that absorbs quantities of carbon dioxide, or in this case, heat. The International Union for the Conservation of Nature (IUCN) states that “the ocean absorbs vast quantities of heat as a result of increased concentrations of greenhouse gases in the atmosphere, mainly from fossil fuel consumption,” as GHGs trap incoming radiation in the Earth’s atmosphere, causing the climate to warm. The Fifth Assessment Report from the Intergovernmental Panel on Climate Change (IPCC) found that the ocean has absorbed more than 90% of the excess heat generated from GHG emissions since the 1970s. 

While sinks sound like the solution to all our climate problems, they have a limited storage capacity. In terms of ocean heat absorption, known as ocean heat content, the maximum quantity of heat it can absorb without undergoing any physical or chemical changes has been surpassed, resulting in the sea surface temperature (SST) and ocean acidification we see today. Moreover, as the ocean is so large, the response time is often delayed, so despite the predicted plateau of GHG emissions this decade, increases in ocean heat content show no indication of slowing down. In turn, this has impacts for sea-level rise, sea ice loss, and coral bleaching, with the latter being the greatest ecological concern in the Maldives. 

When SST, for the majority of coral reefs are at shallow depths, is too warm, coral bleaching occurs because it causes the corals to expel the symbiotic algae (zooxanthellae) living within their tissues, causing the coral to turn completely white. The coral is not dead but is under stress, but is subject to increased chance of death. Temperature is not the only thing that can cause this; changes in light availability, nutrients or pH can also cause bleaching. In the Maldives, however, SST increase is the main driver.

The SST in the Maldives records an average of 28-30°C, but can vary across the island ecosystem. Over the last two decades, the SST of the Maldives has begun to increase beyond the resilience of local coral reefs. In the pre-2000s, there were seven bleaching events in the Maldives: in 1977, 1983, 1987, 1991, 1995, 1997 and 1998 with the last being the most severe. In 1998, over 98% of shallow water corals died during the bleaching event that was caused by unusually high SST during an El Niño event. 

Bleaching events have continued throughout the 2000s, the most devastating being the recent 2016 mass bleaching. In their report on the event, the IUCN states that ‘the 2015-2016 El Niño weather phenomena and associated sea surface temperature anomalies in 2016 caused one of the largest recorded episodes of mass bleaching in the Maldives’. In 2016, on exposed outer reefs, SST reached a maximum of 32-33°C, while lagoonal reefs reached 35°C and higher, an estimated 1-2°C higher than average. The 2016 bleaching event affected around 70% of corals across the country. Data from the National Oceanic and Atmospheric Administration (NOAA) shows that the Maldives is often placed on Alert Level 1 or 2 for coral bleaching during March and April every year. 

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While it is not guaranteed that each year will succeed the next in SST increase or bleaching extent, the overall trend is that SST in the Maldives is increasing, which is predicted to result in more bleaching events. However, the recent recorded resilience of the coral reefs has given hope to scientists and conservationists in the region.

Following the 2016 event, both governmental and private institutions and organisations have implemented action plans. The most salient element to these plans was the need for more intense monitoring of reef systems, as championed by the MUI, located at Six Senses Laamu, which acts as a tourist resort and research centre. Immediately following the 2016 event, they initiated regular bi-annual species surveys of the reef surrounding the facility and around proposed protected areas to help create a designated network of marine protected areas. They also monitor light and temperature at various depths around Laamu’s house reef and use photography to monitor coral recovery. 

With the data collected from the monitoring project, a few solutions to assist with reef recovery have been devised. Initially, the MUI trialled a Coral Nursery Project, in which they planted 180 Acropora and Pocillopora coral colonies from their mid-water rope nurseries onto the house reef, which was supported by continuous monitoring to assess coral health. However, they emphasise that more research is needed on attachment, bleaching and growth of their first batch of nursery-grown corals.

A more technical method called coral micro-fragmentation, developed by Dr David Vaughan, has shown great promise. The technique involves cutting coral into tiny pieces which stimulates rapid growth and placing fragments of the same colony close together, encouraging them to fuse, which can result in growth rates 25-50 times faster than the natural rate. However, while rope nurseries, as mentioned above, and biorock methods are more common, micro-fragmentation is yet to be trialled in the Maldives.

Encouragingly, in March 2019, coral specialists Dr Vaughan and Shidha Afzal found promising signs of natural recovery at Laamu, suggesting that additional intervention such as micro-fragmentation is not needed. They suggest, however, that the technique be applied to Olhuveli Island’s coral reefs, and that resources be invested into establishing more thorough monitoring schemes across the Maldives. 

The future for coral reefs in the Maldives is hard to predict. While climate change models predict increases in SST, models contain their own uncertainties, meaning the extent to which coral reefs are threatened is hard to determine precisely. Efforts to reduce GHG emissions cannot waiver, as this is essential in reducing the effects of ocean temperature increase. However, the noted resilience of coral reef structures following the 1998 and 2016 mass bleaching events shows promise, but the key now is to reduce the other anthropogenic and natural pressures they face to ease recovery. If these systems can be supported by thorough protection, monitoring and recovery strategies, reef systems will have the best chance for survival in a warming world.

Featured image by: Flickr

According to researchers at the University of Hawaii, a newly discovered seaweed has been wreaking havoc on the pristine coral reefs throughout the Northern Hawaiian islands. Individual mats of this seaweed are as big as football fields, have the ability to break off and form tumbleweed-like structures, and- most dangerously- compete with corals for nutrients and light. They have described this seaweed as ‘highly destructive with the potential to outgrow entire reef systems’. 

The seaweed was discovered in the Papahanaumokuakea Marine National Monument, a pristine conservation area with high ecological value considered as a World Heritage Site. The area is home to over 7 000 marine species, 14 million seabirds, and is home to the threatened green sea turtle and endangered Hawaiian monk seal. Each of these species relies on the existing reef systems for shelter, food and structural protection (erosion protection from waves). 

The red seaweed, known as Chondria tumulosa, was initially discovered through surveys conducted by the National Oceanic and Atmospheric Administration (NOAA) back in 2016. The first appearance was in the Pearl and Hermes Atoll. A follow-up survey was conducted in 2019 and it was then that researchers discovered their alarming growth rates that had covered entire reef systems. From DNA testing, there is no existing match of known algae, hence it is considered a new type of seaweed in the genus Chondria. 

According to the US National Invasive Species Information Center, the new seaweed is not considered invasive, as it is unknown whether it was introduced to the native islands by humans or if it originated from there in very small numbers and only recently exploded. Normally, marine invasive species are introduced into new areas via human activities, through fish being accidentally transported on ships, for example. 

Researchers have instead characterised the seaweed as a ‘nuisance species’ due to the sudden ecological impact caused by its expansive and explosive growth. There is conclusive evidence of their abilities to destroy coral reefs; according to the published article, the seaweed was found to outgrow native reef species and replace keystone species, fundamentally, changing the ecological structure of reefs. This has caused irreversible damage to coral reefs in Hawaii because the seaweed is outcompeting the corals for light and nutrients, causing a collapse in the ecosystem. 

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The researchers are also concerned at the seaweed’s tendency to break off into tumbleweed-like structures and travel far distances, posing risks for nearby coral reef ecosystems. 

Another example where an invasive species has decimated the native ecosystem is that of the lionfish. Originating from the South Pacific and Indian Ocean, the lionfish has invaded the Atlantic ocean, with frequent sightings along the southeastern coast of the US and the Bermuda Islands. The Lionfish hunts and outcompetes native fish for food, causing an imbalanced food chain.

In areas where the seaweed had taken over, Heather Spalding, one of the researchers and an algae specialist from the University of Hawaii says that “everything was dead underneath.” The large mats of seaweed essentially block light that corals need to live, making it difficult for these and other marine life to flourish. Known species of fish that graze on algae do not touch the new seaweed, and such areas are void of marine life. 

Determining the causes of a systemic change in the ecosystem is rather difficult but one important factor favouring seaweed growth is increasing ocean temperatures. Opportunistic seaweed can adapt to fluctuating warmer waters and completely overtake coral-dominated systems. An example of this is in the Gulf of Maine where there used to be an abundance of kelp beds but these are currently being overtaken by turf seaweed. Growth of kelp beds favour lower temperatures and they provide large areas of cover for the native fish. Without this cover, native fish are being predated on by migratory fish species.

Seasonal changes can contribute to seaweed blooms throughout the year, but with over 20 years of NOAA observations and surveys in the area, the researchers have concluded that it is not an ordinary seaweed seasonal growth, but rather a symptom of an existing problem, such as increasing water temperature from climate change. 

To combat this nuisance seaweed and save coral reefs in Hawaii and beyond, it is vital to find out the origins and causes of growth, both of which are still unknown at this stage. The researchers are returning to the area to study for more information.

Featured image by: Mike Cialowicz

A team of marine scientists and architects in Hong Kong has created the first 3D-printed terracotta ‘reef tiles’ to help restore eroding local corals. In July, the first clay coral tiles were placed on the seafloor at Hoi Ha Wan Marine Park in Sai Kung as part of a week-long endeavour. Could this be the future of coral restoration and conservation?  

Marine scientists from the Swire Institute of Marine Science (SWIMS) have been collaborating with architects from Hong Kong University (HKU) to construct the world’s first terracotta coral tiles in the hopes of conserving marine habitats. 

Built at HKU’s Faculty of Architecture, the Reformative Coral Habitats Project has been printing clay hexagonal tiles mimicking the natural shape of brain coral since 2016. The 3D-printed tiles placed on the Hong Kong corals limits negative impacts on the ocean’s biodiversity and prevents potential interference with natural coral’s growth patterns. Vriko Yu, a student involved in the project, said the coral tiles act as a ‘substrate that can facilitate coral restoration, while conserving the local biodiversity’.  

The project will see the installation of 128 reef tiles, covering approximately 40 square meters of seafloor in total, at three sites within the marine park. One of the three sites was so badly damaged that its coral communities had deteriorated into sand. 

“Our hope is that our planted corals can become big enough to stabilise themselves and form a natural habitat,” Yu says.

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hong kong corals
Photo by Agriculture, Fisheries and Conservation Department via Hong Kong Free Press.

Weighing around 20 kilograms and measuring 65 centimeters in diameter, each tile consists of three parts: the legs, nine-grid layers and six coral-like layers. Together, the tile units act as an anchoring bed for corals to attach to and grow. Lidia Ratoi, assistant lecturer at HKU, says, “the tiles aren’t conventional tiles. Hong Kong’s subtropical climate entails much underwater sedimentation. That’s why our tiles have a lot of perforations so that sediment doesn’t deposit on the surface and suffocate the corals.”

The team hopes that once the environmentally-friendly terracotta tiles have helped to regenerate coral communities, they will erode and disappear into the seafloor. The 3D printed corals have also been carefully designed to withstand the unique water conditions in Hong Kong- marked by water pollution, overfishing, bioerosion and excessive sedimentation- which precipitated the collapse of local marine ecosystems, including corals.

Hong Kong waters are one of the harshest environments for coral to thrive in; those that are able to grow and flourish in such environments are referred to as ‘super-coral’. “Hong Kong is not an easy place for corals … The water quality has improved a lot over the last decade which has given us one important condition to keep the corals healthy. However, there are some external factors like red tides and typhoons which could take away our efforts in a blink of an eye,” Yu told Hong Kong Free Press. 

In addition to restoring marine life and providing habitats for small fish, coral reefs protect coastlines from storms and erosion, provide jobs for local communities, offer opportunities for recreation and are a source of food and new medicines. 

Going Forward

As the project develops, the team will monitor the sites quarterly, collecting data on the amount of corals that attach to the tiles and the biodiversity levels within the developing reefs. Though still in its early stages, the project’s success thus far is a positive advancement towards marine preservation and conservation in Hong Kong. Yu hopes that the project will encourage and inspire other cities to preserve and restore their local reefs: “If we can do it in Hong Kong, we believe other metropolises can do it, too.”

The marine team estimates that the effort will generate a total area of restored coral habitat of about 40 square metres. “This is quite small compared to the total area of coral communities in Hong Kong,” said David Baker, director of SWIMS and associate professor. “However, even small patches of corals can enhance local biodiversity by creating a home for other species, and small patches can be very important in the long-term by generating propagules – baby corals that can settle on nearby areas, thus spreading corals naturally in our area.”

Featured image by: Vriko Yu


In late March, the Government of the Seychelles announced that it will extend the protection of its seas to 400 000 sq km, an area twice the size of Great Britain, fulfilling its promise to protect 30% of its surrounding marine territory and biodiversity. What does this mean for the future of the archipelago’s marine biodiversity?

The Seychelles, an 115-island archipelago off the eastern coast of Africa, is bursting with marine biodiversity and endangered endemic species that it endeavours to protect. Home to the vulnerable Dugong, a saltwater cousin of the manatee, the critically endangered hawksbill sea turtle, and over 320 different species of coral, the Seychelles are teeming with marine life, making its protection all the more important.

Seychelles’s Marine Protected Area

The new Marine Protection Area (MPA) is part of a debt-for-nature initiative facilitated by the US-based NGO, The Nature Conservancy. Financial sponsors allowed the island nation to restructure its US$21.6 million international debt into funding for an MPA expansion plan.

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With over one third of the local economy tied to fishing and marine tourism, the 30% conservation commitment reconciles economic sustainability with a two-zone Marine Spatial Plan. Marine spatial planning is a collaborative process by which multiple organisations and industries coordinate to establish sustainable practices and resource management plans. Zone one is a 200 000 sq km ‘High Biodiversity Protection Area.’ It expands upon the already-protected Aldabra islands’ UNESCO World Heritage site which includes the world’s second largest raised coral atoll. This zone sees the strongest restrictions on human activity as a ‘no-take zone’, limiting access to only non-extractive tourist uses, and banning fishing, mining and drilling. Zone two is a 217 000 sq km square ‘Medium Biodiversity Protection and Sustainable Use Area.’ According to The Nature Conservancy, this zone is ‘designed to conserve natural ecosystems and support sustainable economic activities, including catch and release fishing, tourism charters, and renewable energy’.

The Seychelles are home to numerous protected marine ecosystems. From coral reefs to sea grasses and mangrove lagoons, these environments host thousands of species, many of which are either vulnerable, threatened or critically endangered. Sea grasses for instance, serve as a widely-used nursery habitat, food for sea turtles and dugongs, help to stabilise sediments, and reduce seawater acidity.  By allowing these ecosystems the ability to grow and flourish, they can be rehabilitated and repair human-induced damage, while having their biodiversity and habitat preserved.  

Environmental stewardship has been a fundamental part of the Seychelles’ mission since its inception. As article 38 in the Seychelles Constitution states: “The State recognises the right of every person to live in and enjoy a clean, healthy and ecologically balanced environment and with a view to ensuring the effective realisation of this right, the State undertakes to ensure sustainable socio-economic development of Seychelles by a judicious use and management of the resources of Seychelles.” 

It is the ultimate hope that the Seychelles can serve as a model for other island nations struggling to balance a “Blue-Economy” within a changing ocean. By showing its commitment to preserving its oceans while ensuring stable economic growth, the Seychelles can show other nations that rely on ocean tourism that this decoupling is possible. 

While the UN has set a goal for 10% of the world’s oceans to be protected by 2020, only about 2- 5.7% of the world’s oceans are currently protected areas.

Featured image by: Klaus Stiefel

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