Tag Archives: bioengineered corals

Repairing Damaged Coral Reefs

Rather than blocking waves, as a sea wall does, a reef slows them, dissipating their energy before they reach land. One estimate, from the University of California, Santa Cruz and the Pacific Coastal and Marine Science Centre, suggests natural reefs prevent $1.8bn a year of flood damage in America alone.

While natural reefs take centuries to grow, hybrid versions can be conjured up in months. The idea began with Wolf Hilbertz, an architect with an interest in marine biology. In the 1970s Hilbertz developed a technique that uses submerged electrodes to run electrical currents through seawater. This precipitates calcium carbonate and magnesium hydroxide out of the seawater, forming limestone similar to that of natural reefs. The artificial reef can become the substrate upon which a natural coral ecosystem develops…Later work with Thomas Goreau, a marine biologist, produced both a catchy name—“Biorock”—and the idea of using the stuff as the basis of coral reefs, and, in particular, for repairing damaged reefs.

In 1996 the Global Coral Reef Alliance, a charity, began using Biorock for reef repairs by growing a six-metre structure in the Maldives. Other repairs have followed in Indonesia, Jamaica and Mexico. The Pemuteran Coral Reef Restoration Project, in Bali, is more than 300 metres long and includes dozens of “nurseries” in which Biorock acts as nuclei for the natural extension of the reef….DARPA a research agency run by America’s Department of Defense, also sees hybrid reefs as a means of coastal defence—in this case protecting the country’s seaside military installations. Lori Adornato, head of DARPA’s “Reefense” project, says the goal is a hybrid reef-type system which will be maintenance-free and self-repairing. Reefense therefore involves not only creating reefs and measuring their effectiveness, but also attracting and fostering appropriate organisms to sustain the reefs’ health, ensuring they can survive even when natural reefs are suffering.

Excerpts from Ocean Reefs: Hybrid Vigor, Economist, Sept. 11, 2021

The Coral Reefs of the High Seas

While the terms “coral reef” and “high seas” are rarely combined in the same sentence, reef-building corals are found in Areas Beyond National Jurisdiction (ABNJ), the high seas. A study that has been published in the Frontiers in Marine Science identified 116 coral reefs in the Atlantic and Pacific Ocean, most of them located outside Marine Protected Areas (MPAs).

There is currently no comprehensive legal framework for the establishment of MPAs in ABNJ. Rather, initiatives to protect critical habitats on the high seas remain scattered throughout the legal mandates of organizations with different management purposes…. Yet, high seas MPAs are possible…. For example, the member countries of the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) and the Convention on the Conservation of Antarctic Marine Life (CCAMLR) have established MPAs in ABNJ of the North Atlantic and Southern Ocean, respectively While these MPAs provide important advances in protecting biodiversity on the high seas, they still only cover a very small portion of the international ocean. 

David Wagner et al., Coral Reefs of the High Seas: Hidden Biodiversity Hotspots in Need of Protection, Frontiers in Marine Science, Sept. 14, 2020

See also Coral Reefs on the High Seas Coalition

Assisted Evolution: Engineering Coral Reefs

Imagine ecologists cultivating whole new breeds of trees to restock a devastated wilderness…. Coral conservation has traditionally focused on minimizing damage from insults such as water pollution, invasive starfish, and destructive fishing or tourism. In the Caribbean, some conservationists have worked to “replant” damaged coral. But Gates and Van Oppen [two scientists]  have something more intrusive in mind. They want to try to alter the genetics of coral or the microbes that live on it. They dubb the effort “assisted evolution.”

Coral’s most remarkable characteristic—being an animal that is part plant—is also its Achilles’ heel in a hotter world. Normally, coral polyps—the individual coral organisms, which resemble a sea anemone the size of a pinhead—live in harmony with their algal partners, which help feed the polyps and give corals their bright colors. But during heat waves, the relationship sours. Overheated polyps perceive the algae as an irritant and eject them like unwanted squatters. The coral is left bleached, bone-white and starving. If the heat persists, the coral won’t take in new algae and can die.  The bond between coral and algae is complicated, however, and still not fully understood. Just 25 years ago, for example, researchers believed that coral housed just one variety of symbiotic algae. Now, they have identified hundreds. And they are just beginning to examine the role played by the coral’s microbiome, the menagerie of bacteria that inhabit a coral polyp.

Coral bleaching right.

But the complexity also offers multiple paths for scientists trying to forge a less fragile bond between coral and algae. Today, four major lines of research exist: One involves cross-breeding corals to create heat-tolerant varieties, either by mixing strains within a species or by crossing two species that would not normally interbreed. The second enlists genetic engineering techniques to tweak coral or algae. A third tries to rapidly evolve hardier strains of coral and algae by rearing them for generations in overheated lab conditions. A fourth approach, the newest, seeks to manipulate the coral’s microbiome…

In 2018, Cleves [scientist] became the first to report successfully using the CRISPR-Cas9 gene-editing tool on coral. CRISPR is often touted as a method for making genetically modified species. But Cleves says he isn’t interested in creating new kinds of coral. Rather, he sees CRISPR as a tool for deciphering the inner workings of coral DNA by knocking out, or disabling, genes one by one. He hopes to identify genes that might serve as “master switches” controlling how coral copes with heat and stress—knowledge that could help researchers quickly identify corals in the wild or in the laboratory that are already adapted to heat.

Either way, such efforts to re-engineer coral reefs make people such as David Wachenfeld, chief scientist for the Great Barrier Reef Marine Park Authority here, uneasy. The authority is supposed to protect the reef and regulate activities there. In the past, that meant a hands-off approach. Now, he concedes that “it is almost inconceivable that we’re not going to need these tools.” But, he adds, “That doesn’t mean I’m happy about any of this. This is crisis management.”

He ticks off a list of potential difficulties. Scientists focused on breeding heat-loving coral have to avoid weakening other key traits, such as coping with cold. Introducing a new coral on the scale needed to make a dent on a network of 2900 reefs spanning an area half the size of Texas is a daunting challenge. Even in its damaged state, the Great Barrier Reef still contains hundreds of millions of corals—enough to swamp the genetic impact of new coral species…

Could some kind of “super coral,” as some researchers have dubbed them, also run amok in delicate coral ecosystems.

Excerpts from  The Reef Builders, Science, Mar. 22, 2019

Meddling with Nature: Is it Right? Is it Fair?

Many envisioned environmental applications of newly developed gene-editing techniques such as CRISPR might provide profound benefits for ecosystems and society. But depending on the type and scale of the edit, gene-edited organisms intentionally released into the environment could also deliver off-target mutations, evolutionary resistance, ecological disturbance, and extinctions. Hence, there are ongoing conversations about the responsible application of CRISPR, especially relative to the limitations of current global governance structures to safeguard its use,   Largely missing from these conversations is attention to local communities in decision-making. Most policy discussions are instead occurring at the national or international level even though local communities will be the first to feel the context-dependent impacts of any release. ..

CRISPR gene editing and other related genetic technologies are groundbreaking in their ability to precisely and inexpensively alter the genome of any species. CRISPR-based gene drives hold particular import because they are designed to rapidly spread genetic changes—including detrimental traits such as infertility—through populations of sexually reproducing organisms, to potentially reach every member of a species. Villages in Burkina Faso are weighing the release of gene drive–bearing mosquitoes that could suppress malaria. Nantucket Island residents in the United States are considering the release of genetically engineered white-footed mice to deplete Lyme disease reservoirs. New Zealand communities are discussing the possibility of using genetic methods to eliminate exotic predators.

But what if a gene drive designed to suppress an invasive species escaped its release site and spread to a native population? Or if a coral species gene edited to better adapt to environmental stressors dominated reef ecosystems at the expense of a diversity of naturally evolving coral species and the fish that depend on them ? The gravity of these potential outcomes begs the question: Should humans even be meddling with the DNA of wild organisms? The absence of generally agreed on answers can be used to support calls for moratoria on developing and releasing genetically altered organisms, especially those with gene drives (6).

However, the promising benefits of environmental gene editing cannot be dismissed. Gene drives may provide a long-sought-after tool to control vectors of infectious disease and save millions of human lives. Projects to conserve ecosystems or promote species resilience are often intended to repair human-inflicted environmental damage. Put simply, either using this technology irresponsibly or not using it at all could prove damaging to humans, our welfare, and our planet.

At the international level, the Convention on Biological Diversity (CBD) has enlisted an expert technical panel to, in part, update its Cartagena Protocol (of which the United States is not a party) that oversees transboundary transport of living modified organisms to accommodate gene drive–bearing organisms. The International Union for the Conservation of Nature (IUCN) is also developing policy to address the release of gene-edited organisms. Although the CBD and the IUCN offer fora to engage diverse public feedback, a role largely fulfilled by civil society groups, none of these agencies currently use the broad and open deliberative process we advocate….

Different societal views about the human relationship to nature will therefore shape decision-making. Local community knowledge and perspectives must therefore be engaged to address these context-dependent, value-based considerations.  A special emphasis on local communities is also a matter of justice because the first and most closely affected individuals deserve a strong voice in the decision-making process…Compounding this challenge is that these decisions cannot be made in isolation. Organisms released into local environments may cross regional and even international borders. Hence, respect for and consideration of local knowledge and value systems are necessary, but insufficient, to anticipate the potentially ramifying global implications of environmental release of gene-edited organisms. What is needed is an approach that places great weight on local perspectives within a larger global vision…

The needs of ecosystems could also be given voice to inform deliberative outcomes through custodial human proxies. Inspired by legislative precedent set by New Zealand, in which the Whanganui River was granted legal “personhood,” human representatives, nominated by both an international body like the IUCN and the local community, would be responsible for upholding the health and interests of the ecosystems in question. Proposed gene-editing strategies would be placed in the larger context of alternative approaches to address the public health or environmental issue in question…

An online registry for all projects intending to release genetically engineered organisms into the environment must be created. Currently, no central database exists for environmental gene-editing applications or for decision-making outcomes associated with their deployment, and this potentially puts the global community at risk…A global coordination task force would be charged with coordinating multiple communities, nations, and regions to ensure successful deliberative outcomes. As a hypothetical example, genetic strategies to eliminate invasive possums from New Zealand must include representatives from Australia, the country likely to be affected should animals be transported outside the intended range. Similarly, the African Union is currently deliberating appropriate governance of gene drive–bearing mosquitoes to combat malaria on a regional scale. 

Excerpts from Natalie Kofl et al.,  Editing nature: Local roots of global governance, Science Magazine, Nov. 2, 2018

A Resurrection Story: the Great Barrier Reef

Great Barrier Reef, which runs for 2,300km along the coast of Queensland, is one of the icons of environmentalism. Conservationists constantly worry that human activity, particularly greenhouse-gas-induced global warming, will harm or even destroy it….Reef-forming corals prefer shallow water so, as the world’s sea levels have yo-yoed during the Ice Ages, the barrier reef has come and gone. The details of this have just been revealed in a paper published in Nature Geoscience by Jody Webster of the University of Sydney and her colleagues…. They discovered that it has died and then been reborn five times during the past 30,000 years. Two early reefs were destroyed by exposure as sea levels fell. Three more recent ones were overwhelmed by water too deep for them to live in, and also smothered by sediment from the mainland. The current reef is therefore the sixth of the period.

The barrier reef’s ability to resurrect itself is encouraging. But whether it could rise from the dead a sixth time is moot. The threat now is different. It is called bleaching and involves the tiny animals, known as polyps, which are the living part of a reef, ejecting their symbiotic algae. These algae provide much of a polyp’s food, but also generate toxins if the temperature gets too high, in which case the polyp throws them out. That causes the coral to lose its colour.  Polyps can tolerate occasional bleaching, but if it goes on too long, then they die. In the short term, therefore, global warming really does look a serious threat to the reef. It would, no doubt, return if and when the sea temperature dropped again. But when that would be, who knows?

Excerpts from Conservation: A Great Survivor, Economist, June 2, 2018, at 78

The Super-Corals

By some estimates, half of the world’s coral has been lost since the 1980s. Corals are delicate animals, and are succumbing to pollution and sediment from coastal construction. Also to blame are sewage, farmland run-off and fishing, all of which favour the growth of the big, fleshy algae that are corals’ main competitors for space. (The first two encourage algal growth and the third removes animals that eat those algae.) But the biggest killer is warming seawater. Ocean heatwaves in 2015, 2016 and 2017 finished off an astonishing 20% of the coral on Earth. This is troubling, for countless critters depend on coral reefs for their survival. Indeed, such reefs, which take up just a thousandth of the ocean floor, are home, for at least part of their life cycles, to a quarter of marine species. Losing those reefs would cause huge disruption to the ocean’s ecosystem. So researchers are looking for ways to stop this happening.

A growing number of scientists reckon that an entirely different approach to saving coral is needed. If oceans are changing faster than coral can adapt via the normal processes of evolution, why not, these researchers argue, work out ways to speed up such evolution  One way to do this would be selective breeding. Most species of coral spawn on just one or two nights a year, a process regulated by the lunar cycle, the time of sunset and the temperature of the water. The sperm and eggs released during spawning meet and unite, and the results grow into larvae that search for places where they can settle down and metamorphose into the stone-encased sea-anemone-like polyps that are the adult form. In the wild, the meeting of sperm and egg is random. Some researchers, however, are trying to load the dice. By starting with wild specimens that have survived a period of heat which killed their neighbours, they hope to breed heat resistance into the offspring.

This is the tack taken, for example, by Christian Voolstra of the Red Sea Research Centre in Thuwal, Saudi Arabia. He describes it as “making sure super papa and super mama meet and reproduce”. Corals bred in this way at the Hawaii Institute of Marine Biology, on Oahu, survive in water that is warm enough to kill offspring resulting from normal, random reproduction.

The reason corals die when the surrounding water gets too hot is that the microscopic algae and bacteria which live on and in their tissue, and are their main food sources, are sensitive to small changes in temperature. When stressed by heat these symbionts start producing dangerous oxidants. This causes the polyps to eject them, to ensure short-term survival. The reef thus turns ghostly white—a process called bleaching. Bleached coral is not dead. But unless the temperature then drops, the polyps will not readmit the algae and bacteria, and so, eventually, they do die.

Polyps that survive one such ordeal will, however, fare better if temperatures rise again. The second time around they have acclimatised to the change. Some species, indeed, can pass this resilience on to their offspring by a process called intergenerational epigenesis. The Hawaii Institute’s efforts to develop hardier corals thus include administering a near-death experience to them. Ruth Gates, the institute’s director, says the goal is to create reefs “designed to withstand the future”. The institute’s first such reef will probably be grown inside Biosphere 2, an enclosed ecosystem run by the University of Arizona.

Another approach, taken by the Australian Institute of Marine Science (AIMS) in Queensland, is to crossbreed corals from different places, to create hybrid vigour. The results of such crosses are unpredictable, but some survive heat greater than either of their parents could cope with.

The artificial breeding of corals is, though, constrained by their cyclical breeding habits, so researchers at the Florida Aquarium, on Tampa Bay, are trying to speed the process up. The operators of the aquarium’s “coral ark” nursery stagger lighting and temperature patterns to fool the animals into releasing their gametes on a day of the researchers’ choosing. This also permits the co-mingling of sperm and eggs that would not normally meet, thus allowing new varieties to be created. According to Scott Graves, the aquarium’s boss, half a dozen such varieties show most promise of heat resistance, but the team is generating thousands more, “just like a seed bank”, as a backup.

A coral’s fate is tied so closely to the algae and bacteria which live in its tissues that, as Dr Gates puts it, it is best to think of the whole thing as “a consortium of organisms”. This is why scientists at AIMS are keen also to produce algae that withstand higher temperatures without releasing the oxidants that lead coral to kick them out. They are doing so using a process which Madeleine van Oppen, a researcher at the institute, calls “directed laboratory evolution”. In the past few years her team have grown more than 80 generations of algae, repeatedly culling those organisms most susceptible to heat stress and also to acidification, another curse of a world with more carbon dioxide around than previously. The resulting algae release fewer toxins and photosynthesise better in warm water than do their wild brethren..

[A]fter the trauma of bleaching, polyps do extend a preferential welcome to algae that have greater levels of heat tolerance. His team are thus now using special lights to bleach corals. Polyps “stress hardened” in this way will be planted on wild reefs in coming months…

This raises the question of whether the genomes of coral, algae and bacteria might be edited for greater robustness. According to Dr Voolstra, more than ten laboratories around the world are trying to do so. His own team has successfully inserted genetic material into about 30 larvae of a coral called Acropora millepora. Editing corals’ heat thresholds in this way is, he reckons, about five years away.

Whether they are created by selective breeding or genetic engineering, supercorals, the thinking goes, would not need to be placed on reefs in astronomical numbers… That thought, however, does not please everybody. Some object in principle to the idea of releasing human-modified creatures into the wild, or feel that amelioration of this sort is a distraction from the business of reducing carbon-dioxide emissions. Others have pragmatic concerns—that corals bred to survive warming seas might suffer handicapping trade-offs. So regulators have been cautious. The Great Barrier Reef Marine Park Authority, for example, will probably require that the hybrid organisms AIMS hopes to test in the open reef are removed before they begin spawning. …[T]he alternative, of doing nothing, is the equivalent of “ just throwing our hands up in the air and saying, ‘OK, we’re prepared now not to have coral’.” For the world’s oceans, that loss would be catastrophic.

Excerpts from Accelerating Evolution: Refreshing Reefs, Economist, Mar. 17, 2018, at 75