About 360 kilometers from the nearest sea, in the heart of Madrid, a busy team of technicians and researchers from the Zoo-Aquarium of the capital put all their care in the development of a valuable facility in which, with much good work and a a pinch of luck, several colonies of very delicatecorals. The works are part of the SECORE research project, an international initiative whose objective is to obtain through sexual reproduction genetically viable populations of these organisms far from their natural environment. The issue is of utmost importance to much of the scientific community, from climatologists to experts in marine sciences, as the health of reefs is an excellent indicator of the state of the oceans.
Corals are actuallysmall polypsof a few millimeters that possess the ability tofix sea calcium. The calcareous structures that they form remain after the death of the animal and are colonized by other polyps, which causes them to spread over the years, giving rise to reefs. The process has been unchanging for thousands and thousands of years, until now. It is estimated that the effects associated with climate change, coral diseases, overfishing and massive exploitation of the coasts have wiped out 20% of the 285,000 square kilometers of known reefs, which is a threat to biodiversity – reefs are home to a high density of marine life? and annual losses of $ 30 billion, focused especially on two sectors, tourism and fishing. Last September, for the first timecorals on the Red List of Threatened Speciesproduced by the World Conservation Union: theTubastraea floreanaand theRhizopsammia Wellingtonof the Galapagos are considered critically threatened, and thePolycyathus Isabelait has been designated as vulnerable.
Four years ago, a report on the State of the World’s Coral Reefs indicated that half were in danger and that, if no action was taken,could disappear in two decades. Since then, things don’t seem to have gotten much better. The figures dance according to the sources, but all the experts and organizations that analyze the state of the corals agree that they are disappearing at a dizzying rate. Thus, according to a study by the UN Environment Program, almost a third of corals have vanished, and 60% are expected to do so in 2030.
According to Donald Kennedy, editor of the magazineScience, the explanation must be sought mainly in therise in sea temperatureand theexcess emissions of carbon dioxide and other greenhouse gases. About 30% of the carbon dioxide produced by industry is absorbed by the sea. When this happens, bicarbonate and hydrogen ions are formed, which lower the pH of the ocean, altering its acidity. The phenomenon directly affects the development of carbonate that corals take advantage of to develop their structures. Furthermore, it is estimated that since the Industrial Revolution, the pH has dropped globally by 0.1, and that by the end of the century it could even drop by 0.4. This mainly affects shallow-water corals, which develop in a narrow range of temperatures, and which are bleaching from the heat.
Drew Harvell, Professor of Ecology and Evolutionary Biology at Cornell University, head of the Coral Diseases Research Team, says that theincreased acidity of the watersprevents these organisms from forming their calcareous skeletons. ? Acidification threatens all life forms that have calcareous skeletons, from corals to crabs. We estimate that in just five decades CO2 levels will be so high that the situation for reefs will be unsustainable. Furthermore, although we can reduce overfishing and local sources of stress that may affect corals, in the medium term it will be necessary to address the CO2 problem.? Ove Hoegh-Guldberg, Director of the Center for Marine Studies at the University of Queensland in Australia, stresses the importance ofcoral reefs😕 are ecosystemsessential in the ocean food chainand directly provide livelihoods to some 100 million people living on the coasts of tropical developing countries; the loss of corals exposes the population to flooding, causes coastal erosion and the loss of billions of dollars a year to the fishing and tourism industries.?
An article published last December in the magazineScienceconfirms this trend. In it, an international team of scientists points out that the concentration of carbon dioxide in the atmosphere will soon exceed 500 parts per million and temperatures will rise by around 2 ° C between 2050 and 2100. A group of experts attached to the Coral Reef research program Targeted Research has pointed out in this same publication that once the 560 parts per million are exceeded, the calcification process is reduced by 40%. ? By 2100, the oceans will be so acidified that 70% of the habitat of deep-sea corals, which until now was considered relatively safe from the effects of climate change, will be uninhabitable for these organisms.?
In a report on the state of deep-sea corals, the U.S. National Oceanic and Atmospheric Administration (NOAA) notes that coral reefscold water corals, which develop between 50 and 3,000 meters deep, are very sensitive to physical changes in the environment. Precisely, last January, a team of researchers announced the finding nearBarcelonaof about400-million-year-old coral fossilsunique in the world, capable of moving to colonize other areas, avoid predators or dig up before falling sediments. Their morphology, however, is similar to that of modern deep-sea corals, very long-lived and slow-growing organisms that are being affected by the exploitation of energy resources and deep-sea trawling. The paleontologist from the University of León Esperanza Fernández-Martínez, who was part of the team, points out that this technique is destroying them at such a rate that we may never get to know them precisely.
In Australia, which has the best preserved corals on the planet, experts from the Institute of Marine Science continually monitor these changes, but the reality is that in many areas of the world, corals are not only not protected, but are being depleted, on the one hand to be exported to the West, especially to turn them into jewelry or as decoration for aquariums, as is the case with theCorallium, or to catch some species that live in them and that are considered authentic delicacies in Asian restaurants. Those responsible for the World Union for Conservation of Nature warn especially about the very delicate situation of the Caribbean corals, whose population was reduced by half in 2005 due to a rise in sea temperatures and suffered intense bleaching. Now, these experts fear that this situation will happen again and urge governments to reduce CO2 emissions.
At 10,7000 kilometers from the Caribbean waters, Hudi Benayahu, professor at the School of Environmental Studies at Tel Aviv University (Israel), points out thatsofter coralsdirectlythey melt. ? The stress you are putting on the environment is damaging the symbiotic relationship between soft corals and the microscopic algae that live in their tissues. In Japan, these corals seem to have suddenly disappeared. ? It is as if they had massively vanished in less than two years. Is the area now totally deserted? One of the least appreciated consequences of this loss is that some organisms thrive on the reefs that we could use to treat diseases. The conservation organization SeaWeb, which has launched the campaign “Too precious to wear”, also influences in this regard. ? In many countries, corals are considered a mere accessory, but with their disappearance we may be forever losing the opportunity to find some key drugs. One of the best known that use chemicals obtained from reefs is AZT, a compound used to treat HIV.?
Now himSECORE projectis emerging as a tool to mitigate this trend. Once the gametes have been collected in the massive spawning directly from the sea, they are kept in Kreisel incubators, special aquariums designed for the maintenance of very delicate organisms, such as jellyfish. After fertilization occurs, the developing larvae are transported to the aquariums. ? At the moment they are only taken to US centers, since, on the one hand, the larvae are very sensitive and transport should be brief, and, on the other, because special permits are needed to be imported to Europe ,? he explains to VERY Pablo Montoto, curator of the Madrid Zoo Aquarium, the only Spanish institution that participates in this initiative. It has started from the case ofAcropora palmata, an emblematic species of the Caribbean reef whose populations have decreased by 90% in recent years.?
In research centers,survival and growth of larvae. The very complex process includes reproducing suitable conditions both in the water and in the lighting of the environment. Mitch Carl, from the Henry Doorly Zoo in Omaha, managed to maintain 821 colonies out of the thousands of larvae that were collected for this purpose last August in Puerto Rico, and says he would be happy if a single colony survived after a year. But the incorporation of the use of Kreisel containers is profoundly changing this. According to Montoto, in 2007 1,296 colonies were thus obtained.
At the moment, asexual reproduction of these organisms has been achieved, obtainingcoral cuttings. But, according to Montoto, sexual reproduction offers advantages:? It is clear that for the reef a much less aggressive method; Furthermore, in the future this technique could be used to produce colonies for aquarium or research at an industrial level.? From a biological point of view, obtaining colonies by asexual reproduction is nothing more than obtaining clones whose genetic pool is very limited compared to that of a natural population; thus, it is much more exposed to being completely eliminated by the appearance of a disease or an alteration against which that particular individual from which the clones come was not resistant. The SECORE project will also serve to carry out a very important work of conservation ofAcropora palmata. In this way, a network of aquariums will serve to conserve this species, which has never before been kept away from its habitat due to its special demands for light, currents, water quality and food. Another line of the SECORE, promoted by Mary Hagedorn, of the Smithsonian Institution, involves the cryogenization of the gametes ofAcroporato create a bank of gametes from which viable larvae could be obtained in the future for reintroduction into recovered reefs.
The disappearance of the corals isAccording to Thomas Lovejoy, president of the Heinz Center for Science, Economics and the Environment,the most profound environmental change we have witnessed in our lives?, a phenomenon in which, according to Camilo Mora, a researcher at Dalhousie University, in Halifax (Canada), we are directly involved. In a report published in the magazineProceedingsof the Royal Society of London, Mora adds another factor to the crisis that corals are going through: the increase in population. ? The number of people living in the vicinity of reefs is the main cause of coral mortality and fish loss. Although reefs benefit from policies aimed at reducing emissions or controlling fishing, it is clear that under all these factors is overpopulation. If the forecasts are fulfilled and in 2050 humanity reaches 9,000 million individuals, will corals have to face a global ecological crisis?
Abraham Alonso
To know morewww.secore.org
www.coralreef.noaa.gov
Pale shadows on the reef
Many reefs are being affected by various diseases that cause intense coral degradation. Experts suspect that they will also worsen as the average ocean temperature rises. These are some of them:
1. Yellow band disease.The pathogen that causes it has not yet been identified. Leaves a trail of affected areas in the form of yellow rings.
2. White diseases of the Caribbean.Of bacterial origin, they reveal the calcareous skeleton of the coral. They are related to the increase in water temperature.
3. Aspergilosis. Caused by the fungus Aspergillus sydowii. Some corals are developing some resistance.
4. White syndrome.Unknown cause. Destroy the outside of the coral. Present in the Great Barrier Reef, Hawaii and the Marshall Islands.
Reefs are home to a large number of living things. Among the branches of the Oculina varicosa corals near the Florida coast alone, John Reed, a researcher at the Harbor Branch Oceanographic Institution, found 20,000 invertebrates of 300 different species in 2002. Shortly after, the Center for Applied Biodiversity Science identified the 10 most threatened reefs on the planet and the main attacks to which they are subjected. To protect these true havens of biodiversity, the World Wide Fund for Nature (WWF) indicates that these measures must be taken as soon as possible:
– The number of protected reefs in the world should be doubled.
– These areas must be controlled so that they can recover quickly from the stress to which they are subjected and the effects of climate change.
– Human activity should be significantly reduced in designated places.
– Governments and civil society must collaborate in the control of protected areas.
Biological heat treatment
It’s a sunny afternoon and Andrew Baker is in a knee-deep tank of seawater at the University of Miami’s Rosenstiel College of Marine Sciences experimental hatchery. He has straight hair and tanned skin, and his image matches that of a model more than that of a respected British scientist. At 35, Baker has a Ph.D. in marine biology and is interested in corals. Especially those that rest at the bottom of the tank.
“Look at this one,” he says, pulling a hand-sized bluish-gray piece out of the water. ? It is in perfect condition, just like that other one, the one with the bright green grooves. These colors are conferred by the alga zooxanthella ?. The zooxanthellae, a member of the dinoflagellate group, is a permanent tenant in many corals. It pays for the rent by giving the coral polyps energy in the form of carbon compounds derived from photosynthesis. In fact, this tiny alga supplies up to 90% of the coral’s energy needs.
But zooxanelle is intolerant to heat. Some species cannot withstand the rise of a single degree centigrade, and flee in terror from their calcium carbonate buildings, turning them white and leaving the reef vulnerable to all kinds of diseases. That’s when the delicate coral polyps begin to starve. The hardiest species can last a few weeks without their algae … but little longer.
Andrew Baker wants to give corals a chance to survive climate change, which will most likely warm the water in which they live. His strategy is as simple as it is interesting: to inject into some more vulnerable pieces of coral the zooxanthella from other species of coral that are more tolerant of warm water. For now, the experiment will be confined to these university tanks, but in a few years, Baker plans to work in the open sea, applying this treatment to some selected pieces of coral, which he will cover with a protective cap to see what happens.
Baker’s approach to zooxanthellae was first featured in the magazineNaturein 2001, where he refers to the genetic differences of the various classes of zooxanthellae, something that until now no one had bothered to explore. In fact, all algae were believed to be the same. However, Baker’s lab proves otherwise. Frozen in a cryogenic sleep of minus 115 degrees Celsius, 12,000 coral tissue samples from 20 countries with their zooxanthellae await their turn to pass under the microscope. So far, Baker’s studies have made it clear that zooxanthella is a kind of heat shield. They also showed that some corals adapted better to warm water, “contracting” more heat-tolerant algae after undergoing traumatic bleaching. ? It is like in a tropical jungle, where there are plants that are more resistant to the sun and others that need shade ?, says the biologist, hurrying to place the samples under the water again. ? And in a reef it happens that sometimes a species of coral can be associated with more than one species of algae, which complicates things.?
Baker’s research has earned him $ 150,000 from the prestigious Pew Fellowship in Marine Conservation for a three-year project during which his group will try to develop ways to inoculate the most delicate corals against the looming problem of global warming. “Rather than simply documenting the decline and writing reef obituaries, he is looking for innovative solutions to prevent his demise,” says Ellen Pikitch, executive director of the Pew Institute for Ocean Science.
Angela Posada-Swafford
