Tag Archives: reef

Pristine coral reef found in Tahiti is as yet unaffected by bleaching

UNESCO scuba divers have discovered a new coral reef in the depths of Tahiti’s coastline.

Image credits UNESCO / Alexis Rosenfeld / 1 Ocean.

Most of the news regarding coral reefs we’ve heard recently revolves around bleachings — deadly events that take place when waters get too hot for corals to survive. Amid this backdrop, we get a rare piece of good news: divers from the United Nations Educational, Scientific and Cultural Organization (UNESCO) report discovering a new, massive reef off the coast of Tahiti, the largest island in French Polynesia, South Pacific.

The reef is composed of rose-shaped corals, untouched by humans so far, and in surprisingly good health given the global plight of coral reefs.

New reefs

The reef, which remains unnamed so far, measures around 1.9 miles (3 kilometers) in length and between 98 to 213 feet (30 to 65 meters) across. It formed at a depth of between 100 and 180 feet (31 to 55 meters), unusually deep for a coral reef in the tropics; they are usually found in shallow water, less than 82 feet (25 meters) from the surface.

Researchers believe that this depth helped insulate the reef from the brunt of climate-change-induced effects.

An encrusting plate coral species, Pachyseris speciosa, is the main dweller of the reef. It forms rose-like groupings that can reach up to 6.5 feet (2 meters) wide. The reef was discovered by seafloor explorers of the Ocean 1 project in November 2021.

“It was magical to witness giant, beautiful rose corals which stretch for as far as the eye can see,” Alexis Rosenfeld, an underwater photographer and founder of the Ocean project, which is jointly run by UNESCO, said in a statement. “It was like a work of art.”

The new reef lies close to the upper limit of the mesophotic zone. Corals in this zone receive less sunlight than those in shallower reefs and, to make up for this lack of light, corals like P. speciosa grow wide and flat to maximize their surface area and enable them to capture more light.

Reefs at this depth have historically been very hard to study, as unprotected divers cannot operate here for long due to a variety of reasons. At the same time, this zone is too shallow for the use of remotely operated vehicles (ROVs), according to NOAA. Novel developments, however, such as the use of air-helium mixes to prevent hallucinations and decompression sickness, mean that divers were able to explore these regions for longer periods of time. Better underwater camera equipment also allows them to capture more data faster than ever before, the statement adds, making the mesophotic zone fully explorable for the first time in history.

With the help of such advancements, the team carried out around 200 total diving hours on the reef, allowing them to map it out in great detail and even observe the spawning of corals.

This discovery is particularly exciting as coral reefs are one of the most at-risk ecosystems on the planet. Climate change, chemical and plastic pollution, sediment run-off, overfishing, explosive fishing (using dynamite), and tourism are all affecting them. In total, 237 species of coral are listed as threatened with extinction on the International Union for the Conservation of Nature (IUCN) Red List to date.

Climate change is the main driver of extinction among coral reefs, as it raises sea-surface temperatures and increases the acidity levels of the oceans. This combination of factors causes coral bleaching, a process through which heat-stressed corals expel their symbiotic, photosynthetic algae, the same organisms that supply them with energy. This process, often repeated at short intervals due to warmer climates, is very usually fatal for coral colonies. Roughly 75% of the world’s reefs experienced some degree of bleaching between 2014 and 2017.

The newly-found reef seems unaffected by climate change so far.

“The discovery of this reef in such a pristine condition is good news and can inspire future conservation,” Laetitia Hedouin, a coral expert at the French National Center for Scientific Research, who was involved with the project, said in the statement. “We think that deeper reefs may be better protected from global warming”.

The findings could suggest that mesophotic reefs may have a vital role to play as backups for shallow-water reefs, which are struggling to survive due to bleaching events. They can also provide new homes for species that rely on those reefs, such as fish and crustaceans, when shallow-water reefs are destroyed.

Researchers develop a new tool to identify at-risk corals

One of the first signs that climate change is already upon us came from heat-stressed corals. Now, new research aims to help us understand which species need protection the most.

Image via Pixabay.

Corals form sprawling reefs below the ocean’s surface, which provide food and shelter for a myriad of species. They are a very important link in marine ecosystems and a very useful indicator for their health. But they’re also being slowly killed by the heat. When corals experience an environment that is too hot for too long they ‘evict’ bacteria they share their chalky bodies with. They can recover from such bleaching events if they’re not too frequent. Sadly, however, climate change is making multiple bleaching events take place in quick succession, pushing corals way beyond their breaking point.

New research aims to address the issue by allowing us to tell which coral reefs are at risk of bleaching before such events take place — an ounce of prevention is worth a pound of cure, after all.

Deadly hot

“This is similar to a blood test to assess human health,” said senior author Debashish Bhattacharya, a distinguished professor in the Department of Biochemistry and Microbiology in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick. “We can assess coral health by measuring the metabolites (chemical byproducts) they produce and, ultimately, identify the best interventions to ensure reef health.”

“Coral bleaching from warming waters is an ongoing worldwide ecological disaster. Therefore, we need to develop sensitive diagnostic indicators that can be used to monitor reef health before the visible onset of bleaching to allow time for preemptive conservation efforts.”

The new approach could help us tell exactly which species of coral need special care and protection from climate change, the authors explain. Around 500 million people depend on reefs or reef-supported ecosystems around the world, so such a tool would be no mean feat.

Apart from higher average water temperatures (which lead to bleaching but also higher water acidity), corals and coral reefs need to contend with rising sea levels (which threaten their access to sunlight), unsustainable fishing (which can physically damage the reefs and damages the ecosystem’s balance), invasive species, impacts from crafts or marine debris, and natural events such as cyclones.

The study looked at how Hawaiian stony corals respond to heat stress to identify the metabolites that indicate the organisms are under stress. They used the heat-resistant Montipora capitata and heat-sensitive Pocillopora acuta corals, which were placed in seawater tanks at the Hawai’i Institute of Marine Biology for several weeks under warm conditions. The chemicals they produced were then compared to those of other corals not subjected to heat stress.

“Our work, for the first time, identified a variety of novel and known metabolites that may be used as diagnostic indicators for heat stress in wild coral before or in the early stages of bleaching,” Bhattacharya said.

The team is hard at work replicating their findings in a larger-scale experiment — so far, they say, the results are quite promising. Their end goal is to create a “coral hospital” featuring a new lab-on-a-chip device, which can monitor the organisms’ health in real time.

The paper “Metabolomic shifts associated with heat stress in coral holobionts” has been published in the journal Science Advances.

Climate change killed half the corals in the Great Barrier Reef — and it could get worse soon

Australia’s Great Barrier Reef has lost more than half of its coral population in the last three decades, according to a new study, with climate change being the main driver of this loss. The researchers found that all types of coral had suffered a decline here, in the world’s largest reef system.

Flickr American Rugbier

Coral reefs are some of the most vibrant marine ecosystems on the planet. They are called the rainforests of the sea, as between a quarter and one-third of all marine species rely on them at some point in their life cycle. Fishes and other organisms shelter, find food, and reproduce near them.

The Great Barrier Reef covers nearly 133,000 square miles and is home to more than 1,500 species of fish, 411 species of hard corals, and 4,000 types of mollusk. It also holds great scientific value as the habitat of species such as the dugong and the large green turtle, both threatened with extinction.

A group of researchers from the ARC Centre of Excellence for Coral Reef Studies in Australia assessed coral communities and their colony size along the length of the Great Barrier Reef between 1995 and 2017. The found depletion of virtually all coral populations.

“A vibrant coral population has millions of small, baby corals, as well as many large ones” said Andy Dietzel, co-author, in a statement. “Our results show the ability of the Great Barrier Reef to recover is compromised compared to the past, because there are fewer babies, and fewer large breeding adults.”

Population declines were seen in both shallow and deep-water coral species, the researchers found. Branching and tablet-shaped corals, which provide habitats for several types of fish, were the worst affected by mass bleaching events in 2016 and 2017 (caused by record-breaking temperatures).

Bleaching occurs when corals that are under thermal stress drive out the algae, known as zooxanthellae, that give them color. Corals can recover if normal conditions return, but that can take decades. A study from last year found that damaged coral colonies had struggled to regenerate because most of the adult corals had died.

“We used to think the Great Barrier Reef is protected by its sheer size — but our results show that even the world’s largest and relatively well-protected reef system is increasingly compromised and in decline,” Terry Hughes, co-author, said in a statement. “There’s no time to lose, we have to decrease greenhouse gas emissions.”

Global temperatures have already risen by about 1ºC since pre-industrial times. The Paris Agreement on climate change commits countries to limit global warming to 2ºC, or ideally 1.5º. If that threshold is exceeded, 90% of the world’s corals will be gone, according to a report by the Intergovernmental Panel on Climate Change (IPCC).

The study was published in the journal Proceedings of the Royal Society B.

Oceans could be unviable for coral reefs by 2100 due to warmer, more acidic waters

Warmer and more acidic oceans could destroy nearly all of today’s coral reefs by the end of the century.

Image credits Marcelo Kato.

New research presented Monday at the Ocean Sciences Meeting 2020 paints a dire picture for the Earth’s reefs. According to the team, between 70% and 90% of coral reefs will disappear in the next 20 years due to a combination of climate change and pollution. By 2100, they add, very few habitats suitable for corals will remain on Earth — if any.


“Trying to clean up the beaches is great and trying to combat pollution is fantastic. We need to continue those efforts,” said Renee Setter, a biogeographer at the University of Hawaii Manoa who presented the findings.

“But at the end of the day, fighting climate change is really what we need to be advocating for in order to protect corals and avoid compounded stressors.”

The issues identified by the team will likely pose major challenges for ongoing reef conservation programs. For example, the researchers cite efforts to grow corals in laboratories and later transplant them back into wild reefs in an attempt to boost their health and resilience. While there is value to such an approach, Setter cautions that few to no habitats will remain suitable for reefs by 2100, rendering the lab-grown corals powerless.

What we need to do, she argues, is to focus on the issues of rising sea surface temperatures and acidity, as these are the two most pressing environmental factors plaguing reefs today. While pollution also poses a very real threat to marine life in general, the team adds, corals in particular are most at risk from environmental changes associated with human CO2 emissions.

Corals are very sensitive to increased temperatures. They can bear them for a short while but will expel their symbiotic algae if exposure continues for longer periods of time in a process known as ‘bleaching’ (these algae live inside the mineralized structures of the coral, giving them their color, and helping feed the polyps). Bleached corals aren’t necessarily dead, but they’re far less resilient to further shocks and stressors. Bleaching events have greatly increased in frequency in the last few years due to climate change.

A bleached coral reef.
Image via Wikimedia.

Setter and co-author Camilo Mora, also at the University of Hawaii Manoa, mapped the areas of the world that would be suitable for coral reefs over the coming decades. They based this on modeling of future environmental conditions that accounted for factors such as sea surface temperature, wave energy, water acidity levels, pollution, and overfishing in areas currently inhabited by corals. They also factored in human population densities and land cover use as proxies for how much pollution and waste would be present at different sites.

They found that most areas that harbor coral reefs today wouldn’t be able to sustain them by 2045; the situation would only worsen by 2100. Small portions of Baja California and the Red Sea would still be viable, but they’re not ideal locations for coral reefs because of their proximity to rivers, the team explains.

“By 2100, it’s looking quite grim,” said Setter. “Honestly, most sites are out [by this time].”

One of the more encouraging findings is that projected increases in human populations (and an associated increase in pollution) pose a limited threat to reef habitats in the future. On the flip side, the team explains that this is because human activity has already caused significant damage to coral reefs — meaning that there are only so many locations left to impact. Still, the authors underline that CO2 emissions and their associated effect on the climate and water acidity need to be addressed if the corals are to stand a chance in the future.

The poster “Impacts of climate change on site selection for coral restoration” has been presented on Monday, February 17 at the Ocean Sciences Meeting 2020 in San Diego (poster number PC14A-1691).

Tropical forests and coral reefs are buckling under interacting threats

Climate change, extreme weather, and human pressure are causing ecosystems across the tropics to collapse, a new study reports.

Image via Stokpic

The authors analyzed over 100 locations where tropical forests and coral reefs have been affected by hurricanes, floods, heatwaves, droughts, fires, and other types of extreme climate. The findings expand our understanding of the health of these ecosystems, especially in the wider context of climate change and damage caused by human activity.

The findings weren’t encouraging. The team echoes previous research and warns that only decreasing CO2 emissions can help reverse the damaging trend of climate change on ecosystems.

Compounding issues

“Tropical forests and coral reefs are very important for global biodiversity, so it is extremely worrying that they are increasingly affected by both climate disturbances and human activities,” says lead researcher Dr. Filipe França from the Embrapa Amazônia Oriental in Brazil and Lancaster University. “Many local threats to tropical forests and coral reefs, such as deforestation, overfishing, and pollution, reduce the diversity and functioning of these ecosystems. This in turn can make them less able to withstand or recover from extreme weather.”

“Our research highlights the extent of the damage which is being done to ecosystems and wildlife in the tropics by these interacting threats.”

Climate change is causing an increase in the frequency and strength of storms and marine heatwaves, which are very damaging to coral reefs; they both reduce the cover of live coral (i.e. they shrink reefs) and cause long-lasting changes in coral and fish communities, which reduce their ability to reduce further impacts.

On land, tropical forests are also threatened by more frequent and extreme hurricanes, the team explains. Such storms cause the destruction of plants which in turn affects the whole of the ecosystem, as animals, birds, and insects directly rely on the plants for food and shelter. The team explains that in some regions, such as the Caribbean, extreme weather events have decimated wildlife by more than half.

Finally, the interplay between higher average temperatures and shifting precipitation patterns has led to a rise in large-scale wildfires in the tropics, the team explains.

“We are starting to see another wave of global extinctions of tropical birds as forest fragmentation reduces populations to critical levels,” explained Dr Alexander Lees, from Manchester Metropolitan University, co-author of the paper.

The team took the 2015 El Niño as an example. One of the areas that felt its impact the most was Santarém, a city in the Brazilian state of Pará, which experienced “a severe drought and extensive forest fires” that affected local wildlife, the team explains. The drought associated with El Niño impaired the forests’ ability to recover from these fires by affecting dung beetles. The species plays a key role in spreading seeds in the forest, and the dry conditions during the 2015-2016 El Niño caused their activity levels to plummet. Coral reefs were also critically damaged by the same El Niño, explains Professor Nick Graham from Lancaster University.

“The 2015-16 coral bleaching event was the worst ever recorded, with many locations globally losing vast tracts of valuable corals,” he explained.

“Worryingly, these global bleaching events are becoming more frequent due to the rise in ocean temperature from global warming.”

The team underlines that we need new conservation strategies to help ecosystems — especially rainforests and coral reefs — handle multiple, concurrent threats and that we need them fast. However, they also explain that local action may simply not be enough if we don’t tackle global climate change.

The paper “Climatic and local stressor interactions threaten tropical forests and coral reefs” has been published in the journal Philosophical Transactions of the Royal Society B: Biological Sciences.

Sick reefs that sound healthy attract back marine wildlife

The world’s largest coral reef is in serious danger — and we’re to blame. Climate change — specifically the warming waters and the increasing acidity of the water from CO2 inputs — is pushing the reefs past the point of no return. Many scientists are experimenting with all sorts of methods meant to help the reef cope and recover in the face of increasing adversity. One such reef recovery technique might just be crazy enough to work — playing underwater sounds typical of a healthy reef from loudspeakers in order to attract marine life.

Researchers in the UK and Australia played audio recordings from speakers positioned underwater at dead patches of the Great Barrier Reef. Over the course of six months, researchers played a range of sounds typical of thriving coral communities, including noises made by shrimp, fish, and other reef-dwellers.

Marine life actually took this cue to start settling down in the sick reef, forming new communities. Up to twice as many fish populated the reefs where sounds were played compared to areas of similar decay that had no speakers installed. The researchers also noted higher biodiversity in areas where sounds were played, with up to 50% more species colonizing the coral.

Australia’s Great Barrier Reef has been hampered by four mass coral bleaching events since 1998, the most recent one lasting from June 2014 to May 2017. The longest, most damaging coral bleaching event on record killed 30% of the reef. Today, experts believe the Great Barrier Reef has declined by more than half in the last 30 years

An estimated half a billion people around the world depend on reefs for income from fishing and tourism. Economic activity derived from the Great Barrier Reef alone is thought to be worth $4.5 billion annually.

Bleaching occurs when the ocean’s waters become too warm and expel the photosynthetic algae, called zooxanthellae, which live in a symbiotic relationship with the coral. Without the algae, the coral dies and seaweeds take over. The main culprit is man-made climate change, which warms and increases the acidity of the waters.

If current trends continue unabated, coral bleaching might affect 99% of the world’s reefs within this century, the United Nations warns. Previously, the U.N. Intergovernmental Panel on Climate Change warned that tropical reefs could decline by 70% to 90% if the planet warms by 1.5ºC compared to preindustrial average temperatures — the upper limit set by the Paris Agreement. At 2ºC of warming, 99% of the world’s reefs could perish.

On this note, bringing back marine life to dead and dying coral won’t actually reverse the damage. Also, what happens to these populations once you turn the speakers off? It seems reasonable to assume that they’ll start evacuating the dead coral.

However, there is value to this approach when combined with coral transplanting. Previously, conservationists have also used other methods to restore the Great Barrier Reef such as “coral gardening”, which involves breaking up healthy coral and sticking healthy branches on the reef. 

The findings were described in the journal Nature Communications.

The Great Barrier Reef sees its greatest spawning event in recent memory

It’s not the best time to be a coral reef — but not all is lost. Over the weekend, corals in the Great Barrier Reef spawned, and it was the biggest spawn event we’ve seen in recent years.

Image via Wikimedia.

Despite extensive damage caused by bleaching events over the last few years, the Great Barrier Reef isn’t ready to throw in the towel just yet. Over the weekend, it engaged in the largest spawning event recorded in recent years. Coral spawning occurs in the Reef in the week after the November full moon, when water temperatures remain around 27 to 28°C. Soft corals being release egg and sperm bundles into the ocean for fertilization, followed by hard corals.

The seed is strong

“The corals are really looking spectacular since the bleaching events of 2016 and 2017,” said Stuart Ireland, a marine biologist from Calypso Productions who filmed the event.

“There was coral spawn everywhere last night. It was like a grey haze with beautiful pink bundles going up; it was a magical night. It’s a testament of how resilient the Great Barrier Reef really is.”

During the spawning period, millions of coral eggs become fertilized and go on to develop into the next generation of coral. The event is vital for the health of the reef. It ensures genetic diversity in individual species and spreads species out throughout the reef. Since corals are immobile, this is their only chance to ‘spread far and wide’ and settle into free spaces.

Typically, these events take place at night. However, the unique conditions this year led to a daytime spawning, explained Russel Hore, a Reef Bio Research Manager at Quicksilver Port Douglas, for Newsport. He adds that there’s a very good chance we’ll see a second spawning in December.

“We expect to see more pressures in the future, but the Great Barrier Reef’s size, complexity and huge biodiversity makes it a very strong ecosystem,” Ireland explains. “The reef has shown us that she is not lying down, she is doing extremely well and fighting for the future.”

The strong spawning event is particularly encouraging as the Great Barrier Reef, despite being the largest coral reef system in the world, is hard-pressed by rising sea temperatures linked to climate heating. Mashable India reports that researchers plan to use this event to restore dead parts of the reef, via the Coral Larval Restoration Project. The project’s page describes it as a “combination of enhanced techniques, aimed at both repairing the reproductive life cycles of corals and re-establishing breeding populations on damaged reefs by ensuring more naturally-produced larvae survive to adulthood.”

However, project leader Professor Peter Harrison said that the Project is, in effect, a bid to buy extra time for corals in the Great Barrier Reef. Climate action, he told Mashable India, is the only way to ensure that reefs will see the future.

3D-printed coral can help save reefs and the fish that live there

New research is looking into 3D-printed corals as a possible cure for the world’s ailing reefs and the animals that call them home.

Close-up of a brain coral.
Image via Pixabay.

Coral reefs aren’t faring very well anywhere on Earth right now. Environmental shocks such as climate shifts, more acidic waters, and pollution are pushing corals — often beyond their limit. As the reefs wither and die, the animals that live there find themselves essentially homeless.

New research at the University of Delaware (UD) is looking into the use of 3D-printed corals as a potential fix.

Hit print

“If the fish on a reef won’t use the 3D-printed coral models as a habitat in the wild, it could place them at greater risk for predation by other larger species,” said Danielle Dixson, an associate professor in UD’s College of Earth, Ocean and Environment’s School of Marine Science and Policy and the paper’s second author.

“If coral larvae won’t settle on 3D-printed materials, they can’t help to rebuild the reef.”

The team has shown that 3D-printed objects don’t impact the behavior of damselfish (a species closely associated with coral reefs) or the survival of a settling stony coral. Fish showed no preference for any of the materials used to print the corals, which suggests that biodegradable materials (such as cornstarch) could successfully be employed in lieu of plastics. This latter finding is particularly relevant in the context of today’s discussion on the role of plastic pollution in the ocean.

The team worked with damselfish and mustard hill coral larvae, which they presented with a coral skeleton and four 3D-printed corals (made from different materials). These artificial corals were replicas of an actual coral skeleton (that the team took around 50 images of using a smartphone). All four filaments used were low-cost, the researchers explain, and widely available; they included polyester and two biodegradable materials, one made from cornstarch and the other from cornstarch and stainless steel powder.

Blue-green damselfish (Chromis viridis) are a common coral-associated fish found in the Indian and Pacific Oceans, while mustard hill corals (Porites astreoides) are a stony coral found in the Caribbean Sea, the team explains. They placed the fish into a tank alongside the corals in a ‘cafeteria-style’ choice experiment — basically, they sat around to see if the fishes preferred one habitat/coral over another. Behavioral analysis showed that the fishes didn’t have a preference between the native coral skeleton and the 3D-printed ones. The fishes’ activity levels (such as frequency of movement and the total distance they swam in the tank) also stayed constant regardless of the habitat they were provided with.

UD alumnus Emily Ruhl, the study’s first author, says that it was surprising to see the fishes behaving the same near a natural or artificial coral skeleton. Furthermore, mustard hill coral larvae settled more readily on 3D-printed coral surfaces than on no settlement surface (as would be the case in a reef destroyed by a storm, for example).

“I thought the natural skeleton would elicit more docile behavior compared to 3D-printed objects,” said Ruhl, who earned her master’s degree in marine biosciences at UD in 2018. “But then we realized the small reef fish didn’t care if the habitat was artificial or calcium carbonate, they just wanted protection.”

When coral reefs degrade, they often lose structural complexity. Reef-associated fish, which tend to spend all of their lives in the reef, rely on this complexity for food and shelter — simpler reefs just don’t give them enough opportunities. Without the proper habitat, they don’t grow to their full size. This mechanism leaves the reef open to an overgrowth of algae (on which larger fish feed) that can destroy the whole reef.

“Offering 3D-printed habitats is a way to provide reef organisms a structural starter kit that can become part of the landscape as fish and coral build their homes around the artificial coral,” Dixson said. “And since the materials we selected are biodegradable, the artificial coral would naturally degrade over time as the live coral overgrows it.”

In addition, 3D-printed coral models can be useful as a control for fish-related laboratory studies, enabling researchers to provide each fish an identical habitat, something that is currently not possible with the use of coral skeletons.

The paper “3D printed objects do not impact the behavior of a coral-associated damselfish or survival of a settling stony coral” has been published in the journal PLOS ONE.

Researchers sequence DNA of coral and their associated organisms

Research from The University of Queensland and James Cook University is looking into which genes allow corals to make friends with algae and bacteria.

Image via Pixabay.

Corals work together with microscopic organisms, establishing symbiotic relationships that benefit both parties. While we’ve been aware of this for some time now, we didn’t understand the biochemical mechanisms that underpin this collaborative predisposition. A new study is shedding light on the subject.

Coral secrets

“Symbiotic relationships are incredibly important for thriving corals,” says Dr. Steven Robbins, the paper’s lead author. “The most striking example of this is coral bleaching, where corals expel their algal symbiotic partners at higher-than-normal water temperatures.”

Corals partner up with algae and bacteria to make ends meet. The coral fishes raw material out of the water and provides housing, and, in return, the algae keeps everyone well fed and plump. Certain stressors, however — especially sustained, excessive heat — can cause a falling out between the two partners, i.e. bleaching. Judging by how well they work together, such a ‘breakup’ is undeniably bad for both, and we know for a fact that coral reefs suffer extensive damage as a result of bleaching episodes.

Dr. Robbins says that the findings further our understanding of these collaborations, and can aid in conserving or perhaps even healing the world’s coral reefs.

“As algae make up the bulk of the coral’s food through photosynthesis, the coral will die if temperatures don’t cool enough to allow symbiosis to re-establish,” he explains. “It’s possible that equally important interactions are happening between corals and their bacteria and single-cell microorganisms (archaea), but we just don’t know.”

The team worked with Porites lutea coral samples retrieved from a reef near Orpheus Island, north of Townsville, Australia. In the lab, they separated the coral itself from its algal symbiotes and associated microbes — then they did genetic sequencing for all the organisms.

After they had a complete picture of the genetic material involved, they used an algorithm to see which genes each actor in the collaboration could draw from.

“This allows us to answer questions like, ‘What nutrients does the coral need, but not make itself?’,” says Dr. Robbins.

Credit: University of Queensland
Associate Professor David Bourne from JCU and the Australian Institute of Marine Science said having high-quality genomes for a coral and its microbial partners was hugely important.

The study’s findings are important as it is the first overall look at the genetic material of corals, their associated organisms, and of the genes that keep them functioning. Associate Professor David Bourne from James Cook University and the Australian Institute of Marine Science calls the findings “truly ground-breaking”, as, in effect, they represent the “blueprint for coral and their symbiotic communities.”

The team hopes that their findings will be put to good use in safeguarding the world’s coral reefs. These beautiful communities have been created by corals over millions of years, but virtually all have experienced bleaching events in recent years as a consequence of man-made climate warming.

“Our coral reefs support incredible diversity and when we lose reefs, we lose far more than corals. There are many threats to coral, but climate change is the most existential [one] for our reefs,” Dr. Robbins said.

“In 2016 and 2017, nearly 50 percent of all corals on the Great Barrier Reef died, and we don’t see this trajectory reversing if carbon emissions remain at current levels.”

On the one hand, research such as this will enable us to better understand corals and to figure out ways of making them more resilient. On the other hand, however, we shouldn’t rest on our laurels. The most straightforward way to safeguard corals and all other life on Earth is to limit our environmental impact by slashing pollution, emissions, and habitat destruction — even kids know this.

The paper “A genomic view of the reef-building coral Porites lutea and its microbial symbionts” has been published in the journal Nature Microbiology.

Researchers look into reviving bleached corals using ‘non-preferred’ algal symbiotes

New research is looking into what makes algae ‘move in’ with their coral hosts — and why the partnership can turn sour, both under normal conditions and when temperatures increase.

Coral polyp.

Coral polyps extending to feed.
Image credits Егор Камелев.

What we know as corals aren’t really alive. They are large exoskeletons built by tiny animals called polyps. Tiny but industrious, these polyps work tirelessly to create the world’s wonderfully colorful coral reefs. A polyp has a sac-like body that ends in a mouth crowned with stinging tentacles called nematocysts (or cnidae). These animals filter calcium and carbonate ions from seawater that they combine to form the limestone (calcium carbonate) they use to build corals that protect their soft, defenseless bodies. If you ever get a chance to visit a coral reef at night, you’ll see these polyps extend their tentacles out to feed.

However, none of this would be possible without the help of various species of single-celled algae we call zooxanthellae, a type of dinoflagellate. These algae live in symbiosis with the polyps, taking up residence inside their cells in a mutually-beneficial relationship: the algae produce nutrients via photosynthesis, while polyps supply the raw materials. The algae are also what gives coral their dazzling colors, which brings us neatly to the subject of:


Warmer mean ocean temperatures (due to anthropic climate change) can apply so much thermal stress on the polyps that they ‘evict’ their symbiotic bacteria in a phenomenon called bleaching. We refer to it this way because, as the algae get expelled, the coral skeletons revert to their natural color: bone-white. If the bleached coral is not recolonized with new algae soon, however, it can die.

“We’re interested in understanding the cellular processes that maintain those preferential relationships,” says Arthur Grossman from the Carnegie Institution for Science, one of the paper’s co-authors.

“We also want to know if it’s possible that more heat tolerant, non-preferred algae could revive bleached coral communities even if the relationship is less efficient.”

The team focused on sea anemones, which are actually closely related to coral (they’re both part of the phylumCnidaria). Sea anemones also host algae, but are easier to work with than corals. The researchers looked at the differences in cellular function that occur when Exaiptasia pallida, a type of anemone, is colonized by two different types of algae — one native strain that is susceptible to thermal bleaching (Breviolum minutum), the other non-native but more resistant to heat (Durusdinium trenchii).

“In this study we hoped to elucidate proteins that function to improve nutrient exchange between the anemone and its native algae and why the anemone’s success is compromised when it hosts the non-native heat resistant algae,” Grossman said.

The anemones colonized by the native algae strain expressed heightened levels of proteins associated with the metabolism of organic nitrogen and lipids. Both are nutrients that get synthesized through the algae’s photosynthetic activity. These anemones also synthesized a protein called NPC2-d, which is believed to underpin the cnidarians’ ability to take in algae and recognize them as a symbiotic partner.

Anemones colonized by non-native algae species expressed proteins associated with stress, the team explains. This is likely indicative of a less-than-ideal integration between the metabolisms of the two organisms, they add.

“Our findings open doors to future studies to identify key proteins and cellular mechanisms involved in maintaining a robust relationship between the alga and its cnidarian host and the ways in which the metabolism of the organisms are integrated,” Grossman concluded.

The results can be used to further our understanding of the biochemical mechanisms that facilitate successful interactions between algae species and the corals that house them. Researchers can explore the metabolic pathways identified in this study to potentially find ways to merge corals with more heat-resistant species — all in a bid to help them both survive in the warmer world we’re creating on Earth.

The paper “Proteomics quantifies protein expression changes in a model cnidarian colonised by a thermally tolerant but suboptimal symbiont” has been published in the journal Nature.

Staghorn coral.

Miami dredging caused “extensive coral mortality and critical habitat loss” for the US’ only continental reef

Researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science say that local reefs have suffered extensive damage from sediment plumes stirred up by the 16-month dredging operation at the Port of Miami.

Sediment plume.

Natural sediment plumes from the Mississippi River (right) and the Atchafalaya River (left).
Image credits NASA.

The team estimates that over half a million corals were killed — those that lived within 550 yards (500 meters) of the dredged channel. Dredging operations, which involve clearing the seabed by scooping out mud, weeds, and rubbish with a dredge, seem to have impacted more than 15 miles (25 kilometers) of Florida’s reef tract, resulting in widespread coral death.

Deadly dredging

“Coral reefs worldwide are facing severe declines from climate change,” said Andrew Baker, associate professor of marine biology and ecology at the UM Rosenstiel School and senior author of the study. “If we want to conserve these ecosystems for the generations that come after us, it’s essential that we do all we can to conserve the corals we still have left.”

“These climate survivors may hold the key to understanding how some corals can survive global changes. We have to start locally by doing all we can to protect our remaining corals from impacts, like dredging, that we have the ability to control or prevent.”

Dredging operations at the Port of Miami began in 2013 as part of a larger construction effort in the area. The team analyzed data that was originally collected by consultants as part of the dredge’s environmental monitoring program. This program did note the loss of coral in the area but wrote it off as the consequence of a coral disease that was making a region-wide outbreak at the same time.

The present research ruled out disease by controlling for its impacts: the team looked at losses in coral species that were known to be immune to the outbreak. They tested whether corals closer to the dredge site were more likely to die during the dredging period than those further away. Most of the documented coral losses near the Port of Miami were the result of dredging, the team found.

Staghorn coral.

Staghorn coral, a species of coral in the Florida Reef.
Image via Wikimedia.

“It was important to differentiate these multiple impacts occurring on the reefs to understand the direct effects of dredging specifically,” said lead author Ross Cunning, who began the project while a postdoctoral scientist at the UM Rosenstiel School and is now a research biologist at the Shedd Aquarium in Chicago.

“We brought together all the available data from satellites, sediment traps, and hundreds of underwater surveys. Together, the multiple, independent datasets clearly show that dredging caused the major damages observed on these reefs.”

The team also looked at sediment plumes, which are clouds of suspended sediment stirred up by the dredges — the team reports they’re big enough to be seen from space — and whether they could predict the damage observed on the reefs below. It turns out that they could; the team says that the satellite-tracked plumes had a very high correlation with coral death on the seafloor. This is the first study to show that satellite data can be reliably used to predict dredging impacts on corals and their habitats.

“This connection allowed us to predict impacts beyond where ship-based monitoring was taking place, and showed that dredging likely damaged this reef several kilometers away,” said study co-author Brian Barnes of the University of South Florida.

“While this same relationship may not apply in all projects, this is a remarkable finding that further establishes Earth-observing satellites as independent monitoring tools to fill in gaps where data are otherwise not available.”

Rachel Silverstein, executive director and waterkeeper of Miami Waterkeeper and a co-author of the study says the study uncovered a “devastating story of loss that we cannot afford to ignore any longer.” She hopes that the team’s findings can be used to guide restoration efforts and to prevent similar tragedies in the future.

Florida can boast the only nearshore reef in the continental United States, but its coral cover has declined by at least 70% since the 1970s, the team explains. Some species in this reef — Staghorn corals (Acropora cervicornis), which were once common in shallow water and have declined by an estimated 98% — are now listed as threatened under the Endangered Species Act. The sites directly adjacent to the dredge site have been designated as “critical habitat” for the staghorn corals.

The paper “Extensive coral mortality and critical habitat loss following dredging and their association with remotely-sensed sediment plumes,” has been published in the journal Marine Pollution Bulletin.


Researchers unveil the most comprehensive atlas of coral reefs to date

A new research effort from the Khaled bin Sultan Living Oceans Foundation and the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science created an atlas of the world’s coral reef — the body of data contains maps of over 65,000 square kilometers (25,097 square miles) of coral reefs and their surrounding habitats.


Image via Pixabay.

Scientists now have a new tool at their disposal to accurately map large areas of coral reefs — much cheaper and faster than any time before. Traditionally, coral reef surveys are expensive, slow, and limited in scope. The main problem was that they relied on highly-trained divers swimming through the reefs, gathering data. Using the new model, however, researchers can now create detailed coral reef habitat maps at a regional scale without having to survey the entire reef in person.

Mapped reef

“In order to conserve something, it’s imperative to know where it is located and how much of it you have,” said Sam Purkis, professor and chair of the UM Rosenstiel School Department of Marine Geosciences, and the study’s lead author.

“Developing such an understanding for coral reefs is especially challenging because they are submerged underwater and therefore obscured from casual view. With this study, we demonstrate the potential to use satellite images to make coral reef maps at global scale.”

The atlas is the product of the 10-year long Global Reef Expedition by researchers from the Khaled bin Sultan Living Oceans Foundation, who traveled to over 1,000 coral reefs in 15 countries. They surveyed the reefs down to a one-square meter scale in a bid to help us better understand coral health and resilience. Many of the reefs they surveyed had never been studied before, the team notes.

The survey gathered data on shallow marine habitats such as fore and back reefs as well as associated habitats such as seagrass beds and mangrove forests for key reefs. These associated habitats are key components of tropical coastal ecosystems, the authors explain, which filter water, protect coasts from storms, and support fish populations. Coastal development, overfishing, and climate change impact these associated habitats as they do reefs.

Mapping extent.

The location of sites visited by the Khaled bin Sultan Living Oceans Foundation Global Reef Expedition. Red polygons show the extent of mapping activity and encompass a total area of 65,000 sq. km of habitat situated shallower than 25 m water depth. Accompanying site names in red also.
Image credits Sam J. Purkis et al., (2019), Coral Reefs.

Data collected by divers of the Global Reef Expedition was analyzed and — using ultra-high-resolution satellite imagery –extrapolated across entire reef structures. The team used video footage taken with cameras dropped at precise coordinates along the reef to validate the accuracy of their mapping method. The resulting maps are publicly available on the World Reef Map, an interactive coral reef atlas that anyone can use to explore all of the coral reefs and shallow water marine habitats mapped by the Global Reef Expedition.

“Benthic habitat maps are an essential tool in coral reef conservation as they provide a snapshot of where reefs are located and the status of their health,” said Alexandra Dempsey, the director of science management for the Khaled bin Sultan Living Oceans Foundation and a co-author of the paper.

“Scientists will use these habitat maps as baseline data to help track changes in reef composition and structure over time.”

Although the maps do not cover every reef in the world, they do include a meaningful portion of global reefs, the team says. As it was constructed with data recorded over the last 10 years, it also offers a unique baseline of coral reef health prior to the massive 2017 bleaching event. The team hopes that the publicly-available atlas will help governments, as well as conservation organizations, to protect and restore reefs. It is estimated that 50% of the world’s reefs have been lost in the past 40 years due to climate change and human activity, the paper also writes, underscoring the need for conservation and restoration efforts.

The paper “High-resolution habitat and bathymetry maps for 65,000 sq. km of Earth’s remotest coral reefs” has been published in the journal Coral Reefs.

Great Coral Reef hit by massive surge of muddy water — visible from satellite

As if the corals didn’t have enough going against them, a massive water runoff has now spilled into the sea, straight towards the reef.

Image credits: NASA.

An unusual surge of rainfall in Queensland, Australia, has led to swollen rivers, which in turn have overflown and brought massive amounts of muddy water to the ocean. The plume is so large it can be easily seen from satellite, and has already reached the closest reefs some 60 km from the coast.

“If you look at the remote sensing images, the one that’s standing out at the moment is the Burdekin, which is the biggest river in that area,” Frederieke Kroon from the Australian Institute of Marine Science (AIMS), who is part of a team which is monitoring water quality in the region, told ABC.

“Over the last two weeks, other rivers have produced large flood plumes as well, which have dissipated since then,” but they are still affecting an “extraordinarily large area,” she said.

The muddy water stops sunlight from going through the water, essentially smothering the reef and any other wildlife unfortunate enough to be in the area. The net impact of this damage is not yet clear, but researchers are worried that the longer the plume stays in place, the more damage it will do — and there are currently no strong winds to disperse it.

To make matters even worse, the mud washed into the oceans contains common farming chemicals like nitrogen and phosphorus, which could kill even more corals and seagrass.

We really can’t afford to put even more pressure on the coral reef. Rising temperatures and increasing water acidity have put a tremendous amount of environmental pressure on the coral and caused massive bleaching, putting the entire Great Barrier Reef at extreme risk. In addition to these threats, the reef faces many other threats, including poor water quality, parasites, and increasing touristic pressure. Half of the Great Barrier Reef has already disappeared, and if things carry on as usual, it may very well be gone forever. Saving the reef, if possible at all, will require urgent and massive intervention, and this recent event just adds more salt to the wound.

There may yet be one very thin silver lining to this story: the murky waters might actually work to temporarily reduce water temperatures

“If you want to have a flipside to the story that would be one, yes,” marine scientists Frederieke Kroon told the ABC, “but it’s still a huge disturbance to the reef [after] the bleaching and the cyclones that we’ve had over the last couple of years.”


Rising seas might mean more coral reef islands — if we don’t murder all the corals

There might be a silver lining to sea level rise — emphasis on ‘might’.


Coral reef rim islands, Huvadhoo Atoll, Republic of Maldives.
Image credits Prof. Paul Kench.

New research proposes that rising sea levels may help the long-term formation of coral reef islands, such as the Maldives. However, all the other bits of climate change may destroy any benefits it brings.

Climate change, island change

“Coral reef islands are typically believed to be highly vulnerable to rising sea levels. This is a major concern for coral reef island nations, in which reef islands provide the only habitable land,” says lead author Dr. Holly East of the Department of Geography and Environmental Sciences at Northumbria University, Newcastle.

Coral reef islands aren’t very keen on altitude; typically, they’re less than three meters (about 10 feet) above the water’s surface. This obviously makes them very vulnerable to rising sea levels. However, the same high seas might’ve also created the islands, the team reports.

The researchers studied five islands in the southern Maldives. By drilling out core samples, they were able to reconstruct when and how the islands formed. They report that storms off the coast of South Africa created a series of large waves (‘high-energy wave events’) that led to the formation of the Maldives. These violent waves dislodged large chunks of pre-existent reefs and transported them onto reef platforms. This stacking of reef material created the foundations of the islands we see today.

“We have found evidence that the Maldivian rim reef islands actually formed under higher sea levels than we have at present,” Dr. East adds.

“This gives us some optimism that if climate change causes rising sea levels and increases in the magnitude of high-energy wave events in the region, it may actually create the perfect conditions to reactivate the processes that built the reef islands in the first place, rather than drowning them.”

The seas were around 0.5 meters (1.5 feet) higher than today during the islands’ formations — this allowed the waves to carry more energy. Both the higher sea level and large wave events were critical to the construction of the islands. Now, (man-made) climate change is also pushing up sea levels; the team says that projected increases in both sea level and the magnitude of large wave events could actually lead to the growth of reef islands.

For that to happen, however, you need living, healthy coral in the region’s reef communities, Dr. East stresses. And we’re murdering them pretty fast right now.

“As these islands are mostly made from coral, a healthy coral reef is vital to provide the materials for island building. However, this could be problematic as corals face a range of threats under climate change, including increasing sea surface temperatures and ocean acidity,” she says.

“If the reef is unhealthy, we could end up with the perfect building conditions but not the bricks.”

She also cautioned that “the large wave events required for reef island building may devastate island infrastructure, potentially compromising the habitability of reef islands in their current form.” Factoring in higher sea levels as well, she says that reef island nations need to “develop infrastructure with the capacity to withstand, or be adaptable to, large wave events” — a task she summarizes as being a “challenge”.

Their paper, “Coral Reef Island Initiation and Development Under Higher Than Present Sea Levels,” has been published in the journal Geophysical Research Letters.


Autonomous killer drone aims to save the Great Barrier Reef

A syringe-wielding, toxin-injecting bot will defend the Great Barrier Reef against invading starfish.


It’s quite the looker, too!
Image via Youtube.

It’s definitely a bad time to be a coral. Climate change is stressing the life out of these tiny creatures (literally), causing more and more frequent bleaching events. While this is likely enough to turn most reefs into dry husks on its own, corals also have to contend with overfishing and pollution, which has sped up their decline.

And it seems that the stars are also conspiring against the Great Barrier Reef — or, more specifically, the crown-of-thorns starfish.

Unleash the robots!

Crown-of-thorns starfish (Acanthaster planci) feed on coral, which isn’t generally a problem. If left to themselves, they keep the coral population in check, but not in sufficient numbers to damage the reef. However, there are clues that human activity (most notably agricultural runoff and port activity) has driven up their numbers to such an extent that in 2012 they were responsible for 42% of the total losses of coral, reported Terry Huges for The Conversation.

In a bid to protect the reef against this ravenous tide, Australia plans to unleash teams of killer bots on the starfish.

The idea first took root in 2015, when researchers at the Queensland University of Technology (QUT) showcased the Crown-of-thorns Starfish robot (COTSbot). The bot was capable of autonomously seeking out its targets — with 99% accuracy — and delivering a chemical cocktail to finish them off.

The same team has further refined their idea, resulting in the RangerBot. The new drone (sporting the same yellow garb) can kill starfish just as easily as its predecessor. In addition, RangerBot brings several new tools to bear — it can monitor the reef’s health indicators, map underwater areas, and it comes with an extended battery allowing it to function for eight hours straight — about three times as long as a human diver. RangerBot’s advanced design, low cost, and autonomous capability won it the 2016 Google Impact Challenge People’s Choice prize.

RangerBot can work much cheaper and more efficient than human divers for the task and can operate at any time, be it night or day. It’s the world’s first underwater robotic system designed specifically for coral reef environments using that uses only robot-vision for real-time navigation, obstacle avoidance, and complex science missions.

It is operated using a smart tablet. The researchers also made a concentrated effort to keep the bot as simple to use as possible:

“Weighing just 15kg and measuring 75cm, it takes just 15 minutes to learn how to operate RangerBot using a smart tablet,” said Professor Matthew Dunbabin, who lead the team that designed RangerBot.

“We also spent a lot of time getting the user interface as simple to use as possible so that as many of our stakeholders (from researchers, management authorities and school children) could potentially operate it with a small amount of training.”

While virtually all reefs are struggling, the Great Barrier Reef — being a designated World Heritage Site — enjoys a lion’s share of the efforts and technology dedicated to coral protection and rehabilitation. Drones, cameras, artificial reefs, and computer simulations have all been brought to bear to prevent the reef from undergoing irreversible damage.

Hopefully, these efforts will be successful and other coral reefs around the world will benefit from the lessons learned here.

“Environmental robotics is a real passion of ours and we see so much potential for these advanced technologies to transform the way we protect the world’s coral reefs,” Dunbabin concludes.

Lophelia pertusa

A coral reef longer than Delaware was hiding off the US east coast

A massive coral reef has just been discovered off the coast of South Carolina.

Lophelia pertusa

Alvin collects a sample of Lophelia pertusa from an extensive mound of both dead and live coral. Image credits: Woods Hole Oceanographic Institution.

We’d like to think that we’ve got Earth squarely under our thumb by now, but a new discovery comes to show that the planet still scoffs at us from time to time. Researchers from the National Oceanic and Atmospheric Administration (NOAA), the Bureau of Ocean Energy Management (BOEM), and the US Geological Survey (USGS) report finding a 260-kilometer (160-mile) long coral reef off the coast of Charleston.

Reefer madness

Despite exploring the Atlantic Ocean for nearly six centuries now, we don’t have a very good idea of what its depths hold. However, the discovery of the reef — announced earlier this week — definitely helps improve that image. Furthermore, it helps to flesh out our understanding of how and where corals can develop.

“This finding changes where we thought corals could exist off the East Coast,” Erik Cordes, the expedition’s chief scientist, told The Washington Post.

“And the function of the reefs, in terms of recycling nutrients, is critical to fuel surface productivity and the fisheries we rely on. This discovery is already changing our predictive models for corals, This will undoubtedly lead to new discoveries in the region once we can digest all of the information. That will take months to years.”

The discovery was made under the Deep Sea Exploration to Advance Research on Coral/Canyon/Cold seep Habitats (DEEP SEARCH) initiative, a five-year project that aims to explore the seas off the coasts of Virginia, North Carolina, and South Carolina. DEEP SEARCH aims “to improve knowledge of geology along the U.S. continental margin, the types of communities found on the seafloor, and the mid-water communities that interact with those seafloor communities”.

Judging by what the project’s website details of these areas — “massive submarine canyons and cold-seep communities” of algae that munch on natural gas rather than sunlight — they’re definitely a sight to behold. About a month ago, researchers aboard the research vessel Okeanos mapped several mound-like features on the seafloor.

Visiting the ocean’s bottom aboard the research submersible Alvin, researchers found evidence of coral, which had them understandably excited: as far as we knew, corals had no business living here. Alvin allowed them to take samples up to the surface for inspection. Analysis of these samples revealed that what was initially considered coral debris actually harbored living coral on the top layers.

“We thought that the structure would mostly be rock, and hopefully with live coral cover on top,” Cordes told The Washington Post.

“We have yet to find a single rock on any of these features. Just coral for miles and miles.”

The structures were bio-constructed entirely by corals over several thousand — or even hundreds of thousands — of years, the team explains. A video posted by the Woods Hole Oceanographic Institution shows a time-lapse of the dive: you can see the team pick up samples of corals a short distance to the south of where Okeanos identified the new reef. Most of those coral samples comprise of the species Lophelia — the same species whose rubble formes the reefs.

“As Lophelia grows and dies over time, new Lophelia grows atop the old skeletons, forming continuous reef structures that could stretch much farther than we ever imagined on the U.S. east coast,” explains Caitlin Adams, Web Coordinator at the NOAA Office of Ocean Exploration and Research.

Beyond their academic significance, the findings could also carry political weight. The US is looking to roll back bans on ocean drilling — a move that would reinstate offshore drilling leases, and has been publicly opposed by more than 140 municipalities, The Washington Post reports.

Back in January, the current administration has unveiled plans that would allow companies to drill in the US continental shelf, including in protected areas of the Arctic and Atlantic oceans. The BOEM has identified 47 areas where companies could essentially buy drilling permits.

“The goal of this whole project is to discover new, fragile habitats and make them priorities for BOEM’s management plan for the area in case it is opened up to drilling,” Cordes said.

“It is critical that we know where these places are, or they could be drilling right on top of a coral reef that no one knew was there.”

Great Blue Hole.

UNESCO takes the Belize Barrier Reef off the endangered sites list thanks to conservation efforts

The Belize Barrier Reef has been removed from the endangered World Heritage Sites after nine years, thanks to the country’s “visionary” steps to preserve it.

Great Blue Hole.

The reef’s Great Blue Hole.
Image credits U.S. Geological Survey (USGS).

The 190-mile-long Belize Barrier Reef System has been removed from UNESCO’s lists of endangered sites following a widespread campaign to protect it, the United Nations (UN) reported on Tuesday.

The reef was designated as a World Heritage Site in 1996 and harbors almost 1,400 different species — held to be one of the most biodiverse marine sites on the planet. Charles Darwin himself described it as “the most remarkable reef in the West Indies”. However, the Belize Reef System was listed as “in danger” in 1996 by UNESCO as oil exploration, mangrove deforestation, and illegal land sales and subsequent land use infringed upon the reef’s stability.

Over half of Belize’s population, some 200,000 people, are estimated to depend on the reef directly for their livelihood. Furthermore, tourism is a key industry for Belize, bringing in millions of dollars each year — so these threats to the reef represented a huge concern for the country’s government.

Last December, officials issued an indefinite moratorium on all oil exploration and drilling in the country’s waters — UNESCO says that this decision warranted removing the reef from the list of endangered sites.

“The Belize Barrier Reef Reserve System […] is an outstanding natural system consisting of the largest barrier reef in the northern hemisphere, offshore atolls, several hundred sand cays, mangrove forests, coastal lagoons and estuaries,” the agency said in its description of the region.

“The system’s seven sites illustrate the evolutionary history of reef development and are a significant habitat for threatened species, including the marine turtle, the manatee and the American marine crocodile.”

The UN writes that the “Belizean government deserves tremendous credit” for taking concrete steps towards protecting this unique ecosystem. Marco Lambertini, head of the World Wildlife Fund, also pointed to a public activism campaign that Belizeans undertook to help secure the reef’s future.

“We have seen an incredible turnaround from when the reef was being threatened by seismic testing for oil just 18 months ago,” Lambertini told AFP. “Belizeans stood up to protect their reef, with hundreds of thousands more globally joining the campaign to save our shared heritage.”

The world’s coral reefs are struggling under the effects of climate change. Mass coral bleaching events have become so frequent during the last few years that reefs can’t recover between episodes. Against this backdrop, Belize’s effort — and success — shows that there is still hope for corals everywhere; we just have to work on it.

Billions of plastic pieces are entangled in the coral reefs, slowly killing them

A new study reports that about a third of all coral reefs are littered with plastic, with devastating consequences for the corals.

A survey of 150 reefs found plastic was a common pollutant. Image credits: Kathryn Berry/Science.

Too much

The world is producing an ungodly amount of plastic. Every year, millions of tons of waste end up in the oceans, where they remain indefinitely. Plastics are virtually indestructible, taking hundreds of years or even more to biodegrade completely. The ocean floor is like a cemetery for plastic, and marine wildlife is paying a huge price. This puts an additional stress on corals, which are already severely suffering from rising temperatures.

“The likelihood of disease increases from 4 percent to 89 percent when corals are in contact with plastic,” researchers report in the journal Science.

In order to assess how much plastic there is in the reefs, international researchers surveyed more than 150 reefs for four years (from 2011 to 2014). They found that one-third of them were contaminated with plastic — sometimes large patches of plastic garbage were visible.

“A lot of times we come across big rice sacks or draping plastic bags,” said Dr. Joleah Lamb of Cornell University in Ithaca, US., who led the study. “What we do find is these corals with a lot of complexity like branches and finger-like corals will become eight times more likely to be entangled in these types of plastics.”

However, the fact that so many big pieces of plastic were found around corals might also have an upside: it allows scientists to identify the sources of that plastic, and perhaps start tackling the pollution problem there.

“It’s sad how many pieces of plastic there are in the coral reefs …if we can start targeting those big polluters of plastic, hopefully, we can start reducing the amount that is going on to these reefs.”

Plastic ain’t fantastic

Image credits: NOAA.

Plastic hurts coral in several ways. Firstly, it abrades them. Coral reefs are hotspots of life, including microscopic life such as bacteria. Plastic scrapes the surface of the corals, drastically raising the potential for infection. Secondly, plastic also blocks sunlight from reaching the corals, which can also pose a long-term threat.

In terms of the entire ecosystem, plastic can be devastating for the countless species which call reefs their home. Turtles and fish can mistakenly eat plastic debris and it’s estimated that more than 1 million seabirds die each year from ocean pollution and ingestion or entanglement.

With warmer waters causing already so much damage in the form of coral bleaching, plastic may very well be the last nail in the coffin for coral reefs. That might sound dramatic but researchers have already warned that unless we take massive action — and soon — most of the world’s corals are pretty much doomed.

However, it’s not too late to make a difference. Researchers have found that active environmental policies, especially concerning recycling, can have a big impact.

Australian reefs had the least amount of plastic observed on reefs, while other surveyed reefs in the Pacific area had much more plastic in and around them — probably because Australia is much stricter about what gets dumped in the ocean.

Meanwhile, Indonesia fared the worst when it came to plastic pollution.

“The country’s estimated amount of mismanaged plastics – so the way they deal with their plastic waste – was a strong predictor of how much we would see on the reef,” said Dr. Lamb.

In 2012, it was estimated that there was approximately 165 million tons of plastic pollution in the world’s oceans. Much of it is directly toxic to both marine life and humans, which is dangerous since it tends to build up along the food chain, and often ends up in our plates. A 2017 study found that 83% of tap water samples taken around the world contained plastic pollutants. We have a massive plastic pollution problem, with no solution in sight.

Journal Reference: Joleah B. Lamb et al. Plastic waste associated with disease on coral reefs. DOI: 10.1126/science.aar3320

Reef coast.

It’s “make or break” for coral reefs, says the UN head of Environment

It’s the “make or break” point in the fight for our coral reefs, says the UN’s Executive Director of the Environment Programme. He says the shift away from coal and plastics is good news, and calls for more action from “countries that host” coral reefs to overcome the “huge decline” in the world’s coral

Reef coast.

Image credits Kanenori / Pixabay.

Efforts to save our planet’s coral reefs have reached their “make or break point” thinks Erik Solheim, chief of the UN’s Environment Programme (UNEP). He adds that countries which host such reefs have to step up and, by their example, lead to a world with fewer greenhouse gas emissions, less plastic pollution and lower-impact agriculture.

Speaking to The Guardian after the International Coral Reef Initiative launched is international year of the reef, Erik Solheim said he expected governments “to step up to concrete actions,” Solheim said.

Save the reefs!

Fiji took the lead, with its prime minister Frank Bainimarama announcing new protections set in place for large swathes of the Great Sea Reef by nominating it a Ramsar site. The Ramsar Convention is aimed at protecting wetlands (including coral reefs) that have a large part to play in maintaining global biodiversity and sustaining human life.

Bainimarama paired his announcement with a more disturbing remark: that it was shocking to realize this might be the last generation to ever witness the beauty of coral reefs first-hand.

“Today I appeal to every single person on Earth to help us. We must replace the present culture of abuse with a culture of care,” he added.

Solheim said that another significant step towards coral reef conservation was taken earlier this year, when Belize imposed a moratorium on oil exploration and extraction in its waters. The move was hailed by Belize’s prime minister Dean Barrow, who added that this was the first time such a decision was taken by a developing country.

There are also other clear signs of improvement, Solheim adds, pointing to the global shift away from coal and into renewable energy, efforts to mitigate climate change in general and a growing public awareness on plastic pollution. However, we’re nowhere near out of the woods just yet.

“We have seen a huge decline in the reefs and that is absolutely serious,” Solheim cautioned.

“Beyond the complete moral failure of destroying the enormous beauty and all the different species in the ocean living in the reefs, it would also be an economic disaster.”

What he means by that is that coral reefs sustain the lives of an estimated one billion people around the world — either as direct food sources, as an economic resource, or simply by protecting coastlines.

The decline of the reefs is a global problem, Solheim adds, and global response needs to be well coordinated. As such, he “expects” host countries such as Australia, the Pacific Islands, and the Caribbean “to protect their coral reefs” and lead the way for others to follow. He “strongly” encouraged Australia to renew its efforts of moving away from coal and into renewables, adding that the country has already made important progress “but the faster it happens the better.”


“[Loss of the reefs] would have a huge impact for Australia – the reduction of tourism, and an impact on the fishing industry. Tourism is the most rapidly growing business on the planet and a huge job provider. At a time when every nation is desperate for jobs, restoring reefs is fundamental to economic success everywhere,” Solheim concludes.

During the same event, UNEP announced the start of a collaboration with WWF that aims to “drive an urgent response to combat the decline of coral”.

Ocean exploration reveals trove of natural diversity off Cuba’s shores

An unprecedented expedition revealed Cuba’s stunning marine biodiversity.

Whenever you feel good about your job, just remember that people are paid to snorkel around reefs and look at wildlife. Image credits: Cuba’s Twilight Zone Reefs Expedition/CIOERT at FAU Harbor Branch.

As Cuba opens up to the US and subsequently, to the world, the country is expected to significantly develop its economy due to increased trade, investments, and tourism. But there are also concerns — especially about Cuba’s pristine habitats.

In some ways, Cuba has been frozen in time for the past 20 years, but as relations start to thaw, things will definitely change. In 2015, Cuban researchers joined to speak against these risks and about the need for protecting the country’s environment. Well, the first step towards protecting the environment is to know it, and that’s exactly what this expedition is about.

It took two decades for the researchers from Florida Atlantic University’s Harbor Branch Oceanographic Institute to plan the details with local scientists, but it paid off. They carried out a month-long circumnavigation of the entire coast of Cuba, which spans about 1,500 miles (2,729 kilometers). Except for a few select places, the entire coast was completely unknown in terms of habitats. There was no data and nothing to document what’s happening beyond the shallow reefs.

“This expedition would not have been so successful without the hard work and collaboration of all the scientists from Cuba and the United States who participated in the cruise,” said John K. Reed, chief scientist and research professor at FAU’s Harbor Branch.

They used a remotely operated underwater vehicle (ROV) and snorkeling expeditions to chart and document the subsurface. In total, they designated 43 diving spots. They came up with 20,000 underwater photographs, over 100 hours of high-quality video, and collected 500 marine plants. Oceanographic data and water samples also were also collected daily to evaluate seawater chemistry and patterns of water circulation.

At every single diving site along the coast, researchers found mesophotic reefs. Many of these reefs hosted new species, as well as many of the old familiar faces. The biodiversity of the Cuban reefs clearly rivals that of their Caribbean counterparts.

 “We were thrilled to discover that overall, the majority of the mesophotic reefs that we explored are very healthy and nearly pristine compared to many reefs found in the U.S. We saw little evidence of coral disease or coral bleaching, and evidence of human impact was limited to some lost long lines at some of the sites. Our biggest concern, however, is that we saw few large grouper,” Reed added.

Now that the areas have been described, it remains to be seen how they can be best protected. Around 22 percent of the Cuban shore is a designated Marine Protection Area (MPA). At least four new sites that fit the criteria for an MPA but are not yet designated have been discovered in the expedition.

“This expedition was a very successful collaboration between numerous institutions, universities and scientists,” said Anton Post, Ph.D., executive director of FAU’s Harbor Branch. “These new discoveries will provide important documentation on the density of corals and fish in Cuba and ultimately determine the genetic connectivity of their corals and those collected from the U.S. Flower Gardens Bank and Florida Keys National Marine Sanctuaries.”

The fact that these areas were still relatively untainted was underlined by the fact that invasive species were present, but in much smaller numbers than in other places. The lionfish, for instance — a genus of venomous marine fish found in the Atlantic, the Caribbean, and the Mediterranean Sea — often number in the hundreds in Florida’s reef. Fewer invasive individuals were present around Cuba.

With worldwide reefs being in disarray, protecting these still understudied areas is more important than ever. The country’s thousands of miles of coral reef ecosystems are healthier than those in the Caribbean — let’s try to keep them healthy, shall we?