Tag Archives: corals seed bank

Preserving Seeds that Feed the World: the Svalbard Global Seed Vault

Six hundred miles from the North Pole, on an island the size of West Virginia, at the end of a tunnel bored into a mountain, lies a vault filled with more than 1 million samples of seeds harvested from 6,374 species of plants grown in 249 locations around the globe.The collection, the largest of its kind, is intended to safeguard the genetic diversity of the crops that feed the world.  If disaster wipes out a plant, seeds from the vault could be used to restore the species. If pests, disease or climate change imperil a food source, a resistant trait found among the collection could thwart the threat.

While some countries have their own seed banks—Colorado State University houses one for the U.S.—the Svalbard Global Seed Vault serves as a backup. The vault, built in 2008 at a cost of about $9 million, is owned and maintained by Norway, but its contents belong to the countries and places that provide the samples.  “It works like a safe-deposit box at the bank,” said Cary Fowler, an American agriculturalist who helped found the vault. “Norway owns the facility, but not the boxes of the seeds.”

In 2015, after the International Center for Agricultural Research in the Dry Areas was destroyed in the Syrian civil war, scientists who had fled the country withdrew seeds to regenerate the plants in Lebanon and Morocco.  “It had one of the world’s biggest and best collections of wheat, barley, lentils, chickpeas, faba beans and grass pea,” Dr. Fowler said. “It was the chief supplier of a disease-resistant wheat variety for the Middle East.”  In 2017, the group returned copies of its seeds to the vault.

The 18,540-square-foot seed vault includes three rooms with the capacity to house 4.5 million samples of 500 seeds each—a maximum of 2.25 billion seeds. The environment’s natural temperature remains below freezing year round, but the seeds are stored at a chillier -18 degrees Celsius, or around -0.4 degrees Fahrenheit. They’re expected to last for decades, centuries or perhaps even millennia….

While dwindling diversity might not seem like an imminent threat, four chemical companies now control more than 60% of global proprietary seed sales…That concentration of power, some worry, could lead to less agricultural variety and more genetic uniformity…In the meantime, the seed vault (which doesn’t store genetically modified seeds) will continue to accept deposits in an effort to preserve all of the options it can.

Excerpts from Craven McGinty, Plan to Save World’s Crops Lives in Norwegian Bunker, WSJ,  May 29, 2020

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

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