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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.

Large-scale deep-sea mining operations will soon be undertaken on the international seabed. The International Seabed Authority (ISA) has drafted the long-awaited mining code and is anticipating granting licences to mine in the seabed for precious metals by this summer. What effects will deep-sea mining have on marine habitats and are there any alternatives? This piece has been republished in the run up to World Oceans Day on June 8 2021. 

It was discovered nearly 50 years ago that it was feasible to extract rare earth metals and minerals from the sea floor. Companies and countries have promised that they would start pulling valuable ores from the depths, owing to a rise in demand for batteries for electric cars and to store renewable energy, but commercial efforts have stalled for a variety of reasons, including massive startup costs and the lack of regulations. Until now.

Before deep-sea mining operations can become commercialised, they must adhere to this mining code in order to be granted licences by the International Seabed Authority, an organisation established by the United Nations Convention on Law of the Sea (UNCOLS). The Code intends to provide the rules, regulations and technical guidelines for regulating mining contractor operations. Once approved, a 30-year license is granted to contractors allowing them to mine assigned ‘claim areas’ in parts of the international seabed.

What Are They Looking For? 

The seabed has an abundance of valuable metals such as copper, silver, zinc, manganese, cobalt and other rare earth metals. Three types of mineral deposits valuable to the mining industry are polymetallic nodules, polymetallic sulphide and cobalt crusts. 

Polymetallic nodules are found in the abyssal plains, ranging from depths of 3000 to 6000 meters. The abyssal plains cover 70% of the seabed, making it the largest habitat on the Earth’s surface. Areas where these nodules are found include the Clarion-Clipperton fracture zone (CCFZ) in the central Pacific Ocean. However, the area is not well understood in terms of its ecological function and biodiversity. 

Polymetallic sulphides contain prized metals including copper and gold. They can be found near one of the most productive areas in the ocean- the hydrothermal vents, which provide organic carbon for organisms in the nutrient-limited deep-sea environment. Many of these species are also endemic to these hydrothermal vent areas. 

Cobalt crust is formed by the settling of minerals in seawater on the rocky surface. Cobalt is one of the most essential components of electronic technology, particular for lithium-ion batteries. Deep-sea mining grinds the crust and transports the ore back to the surface, a process which generates plumes that cause particle suspension and blankets the water column with toxic materials. In addition, the seamount may contain a variety of organisms that are harmed by mining. 

An ecological risk assessment on the effects of deep-sea mining was conducted which attempts to evaluate the risk sources and perceived vulnerabilities of the mineral-rich habitat. It concluded that key habitats are vulnerable to habitat transformation due to the effects of deep-sea mining. 

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Understanding the Impacts of Deep-Sea Mining

There is limited knowledge about the deep-sea environment, especially about microorganisms; however, it is known that they play an irreplaceable role in its ecosystem. Recent studies have found that benthic bacteria sequester 200 million tons of carbon dioxide into the biomass on an annual basis. 

On top of that, microbial communities in these deep-sea habitats are highly diverse. Even in the most studied area- the CCFZ, with over 35 years of surveys, new species have been discovered in recent years. Given that it is difficult to cultivate deep-sea microbes due to their highly adaptive characteristics (i.e. ability to withstand high pressure and temperatures), habitat destruction may potentially result in the loss of these and other ecosystem services. 

There is also a prolonged effect of the disturbance on the deep-sea environment. A pioneer impact assessment named DISCOL has been conducted since 1989 which aims to examine the potential impact of future commercial manganese nodule mining in the seabed environment. Artificial disturbances had been made through dragging tracks on the seafloor with a device called a plough harrow. A long-term impact study called the Mining Impact Project shows that these tracks are still visible after 26 years and both the microbial communities and benthic animals have not recovered from the disturbance. 

Why Do We Need Deep-Sea Mining? 

A report conducted by the Institute for Sustainable Futures concluded that even under the ambitious target to undergo a global transition to 100% renewable energy supply by 2050, the demand can be met without deep-sea mining, and that its effects do not warrant the efforts. Additionally, the demand for metals changes overtime. Cobalt is one of the major minerals extracted through deep-sea mining and is one of the most expensive and critical metals for lithium-ion batteries. Many companies, including Tesla, intend to cut down on the use of cobalt batteries and use lithium iron phosphate (LFP) batteries instead.

Some enterprises including Microsoft and Apple are also facing lawsuits; they are accused of violating human rights by forcing children to conduct harmful work without offering safety equipment in the Democratic Republic of Congo, the largest cobalt-producing country in the world. This may also affect the demand of  cobalt in the future, encouraging the development of cobalt-free electronic products. 

What Are The Alternatives? 

Urban mining has been discussed in recent years, which recovers valuable minerals from electronics waste (E-waste) and metal scrap. Mining this waste has potential to benefit both the economy and society. E-waste is categorised as hazardous waste under the Basel Convention, however this has been largely ineffective in controlling the illegal traffic of e-waste. Ghana, as one of the largest receivers of e-waste, imports 150 000 tons of so-called second-hand electronics annually, according to Ghana’s e-waste Country Assessment in 2011, where over 30% was non-functional e-waste. Many of the Ghanaians also rely on open burning to extract metals, while unusable items are transferred to open dumping sites that contaminate the surrounding environment. 

Urban mining is also less expensive compared to conventional mining. A study says that the urban mining of copper and gold from cathode-ray tube televisions and printed circuit boards is 13 and 7 times cheaper than mining virgin metals respectively. 

Commencing on commercial deep-sea mining depends on three criteria claimed by Michael Lodge, secretary general of the ISA, namely the regulation (i.e. Mining Code), technology advancements and market price of the metals. In the last ISA meeting in 2019, delegates convened to review a draft of the Code. The latest draft was released in 2019 and is pending approval in the next meeting by July. The mining may commence as soon as 2023.  

Considering that the international seabed area covers multiple locations, there is still a lack of knowledge on the deep sea environment, including the abundance of sea life in these environments. Urban mining, on the other hand, may serve as an alternative to meet the demand for future technology development, solve public health issues in developing countries, as well as achieving sustainability by close-the-loop.

The ocean is at the front line of mitigating the climate crisis. Making up over 70% of the Earth’s surface, the ocean plays a crucial role in controlling the global climate system through, among other processes, absorbing and storing carbon dioxide from the atmosphere. In the run-up to World Oceans Day on June 8, we’re looking at how as well as polluting the planet and killing animals, plastic waste is also reducing the ability of phytoplankton to absorb atmospheric carbon.

Phytoplankton and Oxygen

Such processes are made possible by microscopic single-celled aquatic creatures called phytoplankton. These tiny organisms, dubbed the ‘ocean’s invisible forests’, generate about half of the atmosphere’s oxygen and sequester as much carbon dioxide per year as all land plants. 

Similar to land plants, phytoplankton soak up sunlight and capture carbon dioxide for photosynthesis, producing oxygen. Just as trees store carbon in their trunks, leaves, stems and roots, phytoplankton store carbon in their bodies. When they die and sink to the seafloor, the trapped carbon in their bodies also sinks deep into the ocean’s waters. 

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The Importance of Phytoplankton

Phytoplankton are at the base of the marine food web, meaning that they provide marine creatures- from the tiny animal-like zooplankton to whales- with food. When phytoplankton and zooplankton are eaten by other larger sea creatures, the carbon in their bodies is transferred to these animals. This carbon will then settle into marine sediments on the ocean floor in fecal pellets and animal carcasses.

The process of carbon removal from the atmosphere and its absorption into seafloor sediments is called the biological pump. Through this process, the ocean regulates the Earth’s climate.

However, the plastic waste crisis will have a detrimental impact on the climate. Every year, 8 million tons of plastic enter the world’s oceans, which are categorised into micro- and  nanoplastics. Scientists continue to examine the effects of plastic debris on the biological pump process. Further, about four-fifths of all trash in the ocean comes from land-based activity, like poor waste management, litter and construction.

Microplastics and Phytoplankton

A recent study published in the journal, Marine Pollution Bulletin found that plastic pollution in the ocean may negatively affect the ocean’s role in removing atmospheric carbon dioxide, which will eventually disturb the global carbon cycle.

Microplastics in the ocean can negatively impact the growth of phytoplankton. Moreover, the abundance of microplasticslike those of the plastic garbage patches comprising thousands of tons of floating microplasticsforms a layer on the surface of the ocean, affecting light transmission and disturbing the efficiency of phytoplankton photosynthesis. Marine microplastics also affect the development and reproduction of phytoplankton and thus interfere with the process of oceanic carbon storage.

Additionally, the study highlighted how microplastics negatively affect zooplankton. Zooplankton, which feeds on phytoplankton, is one of the intermediaries between phytoplankton and other larger aquatic animals. 

Zooplankton-eating phytoplankton ensures the prevention of the stored carbon from re-entering the water and atmosphere. However, the plastic waste crisis disrupts this process. According to a 2015 study on a member of zooplankton known as copepods, microplastics can reduce copepod’s uptake and consumption of carbon; after eating microplastics, their carbon biomass intake was reduced by 40%. 

Microplastics, the study reported, may also alter the sinking rates of zooplankton’s fecal pellets. The pellets contaminated with microplastics sink slower than uncontaminated pellets. The study, however, points out that further research on the effects of microplastics on fecal pellets is still needed, noting that there are only a few studies conducted on the topic.

Because microplastics sink to the ocean floor in these fecal pellets, it may also affect ocean carbon stock, affecting the circulation of organic matter and nutrients in deep ocean water. 

Troublingly, the study notes that the potential impact of microplastics in the ocean’s deepest points remains, to a large extent, unclear. More studies are needed to establish a firmer link between marine plastic pollution and the biological pump.

However, what is clear is that the marine plastic crisis may make our climate worse; in fact, a study conducted in 2014 estimated that nearly 99% of the ocean’s plastic was unaccounted for, suggesting that creatures such as phytoplankton and other larger creatures are eating plastic, affecting their ability to absorb and store carbon. 

What Can Be Done?

Governments need to develop and implement measures to mitigate the plastic crisis. Developed countries must work collaboratively with developing countries, many of which have been named among the worst marine polluters– for example Indonesia, the Philippines, and Vietnam- who are struggling to build adequate recycling infrastructure.

Potential measures to be taken by governments include improving waste management facilities to prevent more plastic waste from entering the oceans and doing more research on how plastic waste affects the oceans. These solutions should be entrenched in government policy to ensure that efforts are effectively implemented and regulated, punishing those corporations and individuals that breach these policies.

Humanity needs to look beyond trees as a solution to mitigate the climate crisis; phytoplankton is one such solution. Further, marine plastic pollution is not just affecting the aesthetics of the ocean; it is affecting the planet’s climate, further exacerbating the crisis and allowing for the creation of climatic conditions that humanity is scarcely prepared for. 

Featured image by: Hani Amir

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. 


A new study has found that warmer ocean temperatures driven by the climate crisis have caused Australia’s Great Barrier Reef to lose more than half of its corals since 1995, which researchers say will continue unless drastic action is taken to mitigate the effects of the climate crisis. 

A variety of corals in the Great Barrier Reef, the world’s largest reef system, suffered a decline over the past quarter-century, with the most drastic falls occurring after mass bleaching events in 2016 and 2017. In August 2019, the outlook of the reef was downgraded to “very poor’ and this year, the reef suffered its third mass bleaching event in five years

The researchers of the study, published in the journal Proceedings of the Royal Society B and conducted at the ARC Centre of Excellence for Coral Reef Studies in Queensland, assessed the health and size of coral colonies across the reef from 1995 to 2017. It found that populations had dropped by more than 50% in all coral sizes and species, but especially in branching and table-shaped corals, the large, structural species which provide habitats for fish and other marine life. 

Terence Hughes, one of the researchers, says, “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.” 

Corals are able to recover if conditions return to normal, but it can take decades. We are living in a world where anthropogenic changes will warm the planet for decades to come before any climate action begins to take effect, so conditions in the reef are unlikely to return to normal in time for a full recovery.

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According to the BBC, a 2019 study found that damaged corals struggled to recover because most of the adult corals had died. According to lead author Dr Andy Dietzel, a healthy coral population should have millions of baby coral as well as many large ones. The ability of the reef to recover has been compromised because there are fewer babies, and fewer large breeding adults.

The reef was designated a World Heritage Site in 1981 for its “enormous scientific and intrinsic importance,” but the past decade has seen the reef damaged by warmer seas which have killed off coral and other sea life and sped up the growth of algae and other contaminants. 

On Twitter, Hughes took aim at government leaders and particularly the “Murdoch press”- referring to Rupert Murdoch, whose titles account for nearly two-thirds of metropolitan circulation in Australia and who famously ignore or vilify climate change research- for ignoring the study. The Australian government has repeatedly resisted calls to reduce carbon emissions even as heat waves, droughts and fires continue to ravage the country. 

The UN has warned that if global temperature rise reaches 1.5 degrees Celsius by the end of the century, 90% of the world’s corals will be wiped out. 

All hope is not lost however. At the local level, nitrogen pollution, which exacerbates bleaching, can be controlled by controlling and mitigating fertiliser and sewage runoff, according to a study. As corals account for billions of dollars in global tourism for many countries around the world, especially Australia, it is certainly in their best interests to mitigate their carbon emissions.

A new study has found that marine heatwaves have become more than 20 times more frequent over the past four decades due to the burning of greenhouse gases. 

A marine heatwave is an extended period of time in which the water temperature in a particular ocean region is abnormally high. The study, published in the journal Science, is the first to look at the anthropogenic impacts on marine heatwaves and was conducted by a team of marine scientists at the University of Bern in Switzerland. By examining satellite measurements of sea surface temperatures from 1981 to 2017, the team found that these heatwaves have become longer, hotter and more frequent. 

In the 1980s, satellites recorded 27 major marine heatwaves, which each lasted about a month with water temperatures reaching a maximum of 4.8 degrees Celsius above average. In the last 10 years, there were 172 major heatwaves across the globe, lasting 48 days on average with temperatures reaching a maximum of 5.5 degrees above average.

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Heatwaves can have lasting, detrimental effects on marine ecosystems. Warmer temperatures can trigger algal blooms, impact on nutrient availability, cause coral bleaching and change fish migration patterns. 

In pre-industrial times, extreme marine heatwaves similar to those seen in the past decade would have occurred once every few hundred to thousands of years. However, the team found that if global temperatures rise 1.5 degrees Celsius- the goal of the Paris Agreement- these heatwaves could happen once a decade or century. If temperatures increase by 3 degrees Celsius, these heatwaves could become as frequent as once a year of decade. 

Charlotte Laufkӧtter, one of the authors of the study, says, “Ambitious climate goals are an absolute necessity for reducing the risk of unprecedented marine heatwaves. They are the only way to prevent the irreversible loss of some of the most valuable marine ecosystems.”

In early June, a fleet of around 260 Chinese vessels reached the limits of Ecuador’s exclusive economic zone around the Galápagos Islands to fish for Humboldt squid (Dosidicus gigas), engaging in illegal fishing. For months, the fleet skirted this area, drawing outrage among Ecuadorans as well as scientists and conservationists around the world.

The fleet remained in international waters and no ship crossed the country’s maritime limits, according to the Ecuadoran authorities, who detected no illegal actions. However, scientists and fishery analysts say the volume of fishing is so high as to potentially overexploit the squid. Moreover, the boats could be capturing species threatened with extinction. Beyond that, vessels within this Chinese fleet have a history of illegal fishing, according to Milko Schvartzman, a marine conservation specialist with the Argentine organization Circle of Environmental Policies, who has studied the fleet for years.

Experts say the presence of these ships is not only a problem for Ecuador but for other countries in the region, too. Every year they travel a route that goes from the South Atlantic off Argentina to the South Pacific near the Galápagos, passing through Chile and Peru. According to Schvartzman, at least two boats that have been caught illegally fishing in Argentine waters and were pursued by that country’s navy were fishing south of the Galápagos in August.

The Route of the Chinese Ships

Between December and May, in the western South Atlantic off Argentina, the controversial Chinese fleet fishes another species of squid, Illex argentinus. Then, between May and July, it moves to the Pacific, passing through the Strait of Magellan, and operates just outside the northern stretches of Chile’s exclusive economic zone. Next it continues toward Peru in the direction of the Galápagos. Then it makes a return trip.

“There are years that they start a little further north,” Schvartzman said. “This year the fleet started the season closer to Peru than to Chile but there have been years in which the fleet has been operating on the edge of Chile’s exclusive economic zone.”

These variations depend on the movement of the squid, said Max Bello, an ocean policy adviser with Mission Blue, a California-based NGO created by renowned oceanographer Sylvia Earle.

In Bello’s opinion, the difference is that this year the ships “have come much closer to the exclusive economic zone and two or three years ago we did not have the level of satellite information that we have today.”

Indeed, ship-tracking platforms, including Global Fishing Watch, show that “we are talking about a gigantic fleet,” said Luis Suárez, director of Conservation International-Ecuador.

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chinese vessels illegal fishing
Hammerhead sharks congregate around Wolf Island and Darwin Island in the Galápagos archipelago. Chinese vessels have been contributing to the illegal fishing of this endangered shark. Image by Pelayo Salinas de León.

However, Bello said it is impossible to know exactly how many boats made up the fleet. “All the numbers we have are not real or official,” he said. “We don’t know how much they are really fishing either.” This is because these ships constantly change their registration, turn off their satellite transmitters and have no observers on board, he said.

report released this month by the international NGO Oceana based on an analysis of the fleet’s behavior between July 13 and Aug. 13 on Global Fishing Watch tried to clarify the scope of the fleet and its activities. It put the number of Chinese vessels at 294, compared with 10 vessels from other nations, and claimed they logged a total of 73,000 hours fishing near the Galápagos. The report found 43 instances where the Chinese vessels in the fleet appeared to turn off their tracking devices, each for an average of two days, a common ploy to obscure illegal fishing activity, although there are innocuous explanations for such breaks, too, such as gaps in satellite coverage.

The large volumes of marine life these boats could be catching is the main concern for scientists. The overfishing of squid could cause ecological problems because various species, some of them emblematic of the Galápagos such as the scalloped hammerhead shark (Sphyrna lewini), feed mainly on them, according to Alex Hearn, a marine biologist and vice president of the California and Mexico-based NGO Migramar. Also, scientists fear that the ships are catching species threatened with extinction.

Industrial and artisanal fishermen in South America who fish for squid are also concerned, as are the companies that process the squid. Pascual Aguilera, a spokesperson for the National Coordinator of Jibieros a Chilean association of artisanal squid fishers, said the fleet “is like a city, a chain, a wall [of boats],” which settle in to fish at the 200-nautical-mile (370-kilometer) limit of the exclusive economic zone, where the territorial waters of each country end. That is why “we find that the resource is increasingly scarce. We have to go looking for it further and further,” the fisherman said.

Alfonso Miranda, president of the Committee for the Sustainable Management of the Giant Squid (CALAMASUR), added that the concern is greater because this fleet “has illegal and transgressive behaviour within our maritime domains.”

In fact, Schvartzman has identified at least two vessels within the Chinese fleet that recently fished outside the Galápagos territory that have a history of illegal fishing and were pursued by the Argentine Navy, captured and sanctioned.

One of those boats is the Hua Li 8. On Feb. 29, 2016, the vessel was detected illegally fishing 800 meters, about half a mile, within Argentine waters. The coast guard attempted to detain the vessel but it fled into international waters without even responding to the warning shots the navy fired.

A few days later, on March 3, the ship reentered Argentine waters. This time it was heading for the port of Montevideo, Uruguay. Argentina sent two coast guard ships and a helicopter to the area and began a five-hour chase. The ship managed to escape, but two months later it was captured by the Indonesian Navy.

This July and August, the Hua Li 8 was fishing outside the Galápagos exclusive economic zone, as Schvartzman confirmed via Global Fishing Watch. He said this is not an isolated event since the Lu Rong Yuan Yu 668, which the Argentine Navy also chased in April this year for illegally fishing, was there too.

A Regional Problem

“This is a regional problem and all countries have a responsibility. None of them are 100% victim,” Schvartzman said, pointing out that the countries provide logistical support to the vessels.

“Argentina has a responsibility because it should not release the captured ships,” he said. The offending vessels are taken to port, where they stay for a while and operators hit with a fine. “Purely economic sanctions are not enough to prevent, discourage and combat predation and illegal fishing,” Schvartzman’s organization, Circle of Environmental Policies, wrote in a document it presented to the Argentine Congress, which is currently working on a bill to toughen the sanctions against vessels caught fishing illegally.

Ecuador, for its part, has at least one oil tanker that supplies Asian vessels. Last year, the country’s navy detected the Ecuadoran vessel María del Carmen IV supplying fuel to the Chinese fleet while it was, like this year, fishing outside the Galápagos exclusive economic zone. The company that owns the ship, Oceanbat S.A, said in a statement addressed to the newspaper El Telégrafo, that it had all the proper permits to carry out its activities.

In addition, Schvartzman’s analysis shows that Panama has mother ships, known as reefers, that receive fish from Asian vessels on the high seas and take it to ports in Peru and Uruguay. The Oceana report documented six apparent transshipment encounters between different Chinese fishing vessels and a Panama-flagged reefer between mid-July and mid-August.

“It does not necessarily mean that the Chinese ship that passed the fish to the Panamanian reefer had been fishing illegally,” Schvartzman pointed out. However, he said, one of the reasons why such transfers, called transshipments, are carried out is to launder fish. “Reefers receive loads from many fishing boats made up of different species that were caught in different places. This [legally and illegally caught fish] is mixed in the hold and no one can later know which ship the cargo that arrives in the reefer belongs to,” he said. In fact, according to the FAO, transshipment is the biggest cause of illegal, unreported or unregulated fishing.

Flor Torrijos, director of the Panama Aquatic Resources Authority, told Mongabay that all Panamanian-flagged cargo ships must have an observer on board. “It is a mandate from the IATTC and Panama that all vessels that provide support to purse-seine vessels must have an observer onboard,” she said, referring to the Inter-American Tropical Tuna Commission, which manages tuna and other fisheries in the eastern Pacific Ocean. She added that there is “considerable control and surveillance over Panamanian vessels everywhere in the world and now especially in this area [around the Galápagos exclusive economic zone].”

“It is important that Latin American countries form an alliance to fight illegal fishing, and part of that is to prevent collaboration with this fleet,” Schvartzman said, referring to port services, transshipments and fuel supply.

President Lenín Moreno of Ecuador announced the formation of a team of experts to design a protection strategy for the Galápagos Islands. Private sector actors in the region — both artisanal and industrial, as well as squid-processing companies — also signed an agreement to demand the regulation and inspection of distant-water fleets, such as China’s.

Faced with pressure, in early August China announced a fishing ban on its boats in the vicinity of the Galápagos exclusive economic zone. Global Fishing Watch indicates that the fleet moved away from the Galápagos around the end of August. However, observers remain skeptical.

“It would be necessary to study whether this closure is going to have an effect or not,” Bello said. “It could be that it coincides with the time when the resource is no longer in that place and they are simply going to move the fleet from place to place, which is part of the normal action of the fishery.”

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

Whilst only occupying 0.1% of the Earth’s surface, seagrass is a vital weapon in the fight against the escalating climate crisis. Worryingly, it is estimated that each year, 7% of seagrass meadows are lost from anthropogenic activities. With greenhouse gas emissions escalating, the role of nature-based solutions is paramount in tackling the crisis head on, and one which requires greater levels of attention and funding if it is to be effective.

Seagrass meadows fall under the term ‘Blue Carbon’, which incorporates different ocean and coastal ecosystems which sequester organic carbon. Other examples of blue carbon ecosystems include mangroves and tidal marshes. 

Thought to be responsible for storing 23-78% of the organic carbon buried in coastal vegetated ecosystems, seagrass is estimated to sequester CO2 twice as quickly as terrestrial forest ecosystems. It is therefore clear that seagrass plays a vital role in sequestering CO2, which in turn helps to reduce atmospheric CO2 emissions.

Researchers have found that globally, seagrass meadows have decreased by 29% since the beginning of the 20th century.  

Seagrass losses have occurred because of a variety of human activities, including coastal developments like dredging and the construction of storm infrastructure, whereby seagrasses and their soils are physically removed, resulting in the exposure of organic carbon in the soil, leaving it vulnerable to oxic conditions, potentially leading to the remineralization of this organic matter into CO2

As well as these direct losses of seagrass, other indirect impacts such as eutrophication and heatwaves can threaten the seagrass canopy, causing the organic carbon stocks in the soil to be exposed which can then be released into the atmosphere as CO2.

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Australia is particularly significant in the conversation around seagrass and blue carbon ecosystems since around 5% to 11% of the world’s blue carbon ecosystems are situated along the country’s extensive coastline. Whilst this makes Australia a key player in helping to tackle the climate crisis via natural mechanisms, and potentially a leader in its ability to protect blue carbon ecosystems, it also makes carbon stocks stored here vulnerable. For instance, the 2010-11 heatwave that gripped Western Australia resulted in 22% of seagrass meadows from Shark Bay being lost, releasing close to 10 million tons of carbon into the atmosphere. 

There is currently a real lack of understanding surrounding the effects of disturbances, such as eutrophication, on organic carbon stocks within seagrass soils and since significant amounts of seagrass are lost due to these disturbances, there is a pressing need to fully understand them to effectively manage these vegetated coastal ecosystems and implement seagrass carbon strategies. 

In a recent study carried out by researchers at Edith Cowan University in Australia, they discovered that over the last four decades, organic carbon stocks from seagrass soils were lost at a greater extent in areas characterised by bare soil exposure. These findings suggest that conservation efforts should be focussed on coastal areas where both organic carbon stocks and erosion are high. 

The UK has lost up to 92% of its seagrass meadows which once thrived along the country’s coastline. Human activity such as anchor damage and port building has played a key role in their demise. However, a primary driver of seagrass loss along the British coastline is nutrient pollution from sewage and livestock waste which causes epiphytes, a microscopic algae, to form which coats the seagrass leaves and prevents them from capturing light. 

In a recent bid to restore seagrass meadows around the British coastline, The Seagrass Ocean Rescue Project has been launched with a 20 000 square metre seagrass meadow being planted off the Pembrokeshire coast. The £400 000 initiative hopes to become the first-ever full scale seagrass restoration project in the UK. 

Seagrass restoration projects are one of a number of nature-based solutions being used to tackle the climate crisis. Research has shown that such solutions could account for a third of the reduction of greenhouse gases required by 2030. However, up until now, only 2.5% of funding for reducing emissions has been given to projects working to restore natural habitats. 

Seagrass meadows pose an opportunity to reduce global greenhouse gas emissions and store carbon for millennia. However, for this to be a successful strategy, more funding needs to be invested into conservation and restoration efforts. If dealt with effectively, seagrass meadows are a powerful tool in the ongoing challenge to tackle the climate crisis, but this will only happen if their value is realised and widespread, global action is taken. 

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

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