The National Oceanic and Atmospheric Administration's Fisheries Service is seeking to add more than 60 coral species to the endangered list, citing climate change.
In the wide-sweeping proposal announced Friday, the Fisheries Service said 59 species in the Pacific and seven in the Caribbean would be listed as endangered or threatened under the Endangered Species Act (ESA).
The Fisheries Service is also proposing that two Caribbean species, the elkhorn and staghorn corals, already listed under the ESA, be reclassified from threatened to endangered.
"Climate change and other activities are putting these corals at risk," said Jane Lubchenco, head of NOAA.
"This is an important, sensible next step toward preserving the benefits provided by these species," Lubchenco added.
Lubchenco says corals provide habitat that support fisheries, generate jobs through recreation and tourism, and protect coastlines.
The proposal is in response to a 2009 petition from the Center for Biological Diversity seeking to have 83 species listed.
NOAA considered listing 82 of the species, and ultimately decided 66 met the criteria. Friday’s action is the result of a court-approved settlement between the agency and the environmental group.
Last April, NOAA scientists reported that more than half of those 82 species were "more likely than not" to face extinction by 2100.
“It’s a bittersweet victory to declare these animals endangered. I’m deeply saddened that our extraordinary coral reefs are on the brink of extinction, but there’s hope that protection under the Endangered Species Act will give them a powerful safety net for survival,” said Miyoko Sakashita, the ocean director at the Center for Biological Diversity.
Climate change is the most important threat to these key ocean species, with more than 97 percent of reefs predicted to experience severe thermal stress, which can cause massive bleaching and mortality, according to the proposal.
Corals are very sensitive to disease and temperature change, and the fact that seas have warmed and become more acidic as carbon dioxide emissions have risen, led to NOAA's proposal and focus on climate change. The acidity weakens the skeletal structure of coral.
The polar bear is the only other species listed under the Endangered Species Act because of climate change, and that's because of shrinking sea ice.
NOAA had never before analyzed so many species over such a wide geographic range. The closest in scope was a review of 30 West Coast salmon and steelhead species in 1994.
Cayman's coral reefs are under threat. - PHOTO: NORMA CONNOLLY
The Cayman Islands Tourism Association is backing the proposed expansion of Cayman’s marine parks.
A public consultation on proposals by the Department of Environment to increase the sizes of protected marine areas ended on Friday, 23 November.
In a statement released by the Cayman Islands Tourism Association, which represents hotels, condos, water sports operations, restaurants, attractions and other tourism-related businesses, the organisation said the Cayman Islands reefs and fish stocks are threatened today as never before and protecting only conch, lobster and grouper, which are protected under the existing Marine Conservation Law, is no longer enough.
“The importance of reef fish, stingrays, sharks, transient mammals, pelagics and coral reef health has been lacking under the current Marine Parks regulations and without new measures we will inevitably follow the same fate that Jamaica and Haiti now face, beyond the point of no return,” the CITA statement read.
The association pointed out that a healthy environment and coral reef systems are Cayman’s biggest asset and why “hundreds of thousands of tourists, residents and businesses live in or visit our islands each year”.
“Protecting the environment is not only good for the environment, but very good for all business and tourism in the Cayman Islands,” the statement read.
It continued: “CITA believes that most Caymanians are in favour of protecting their future and heritage, but not as many are prepared to take the actions needed today to ensure that there is a tomorrow. Minor adjustments and further consultation need to happen, and the most important thing is that the marine parks do not stay the same as that would in fact be a step backward.
“The concept that the Marine Parks is ‘taking away’ is incorrect; the marine parks are giving back and the expansions proposed will do just that – give back more healthy reefs, more fishing stock and more opportunities to make a livelihood from the seas.”
The association acknowledged that not everyone agrees on the details of the proposals to expand the marine parks, but that most people do not want them removed.
During its several public meetings at which it presented the advantages of expanding the marine parks and protecting more of Cayman’s threatened reefs, the Cayman Islands Department of Environment showed that the existing protections and reserves in place have had a positive impact, but that over the years, the health of the local reefs and fish stocks were slowly declining.
“We are facing new threats that did not exist 25 years ago, including continuing development, invasive lionfish, coral bleaching, climate change and more,” the CITA statement read. “CITA members are concerned about what our reefs will look like in the year 2037, 25 years from now.
“We all know that time will come, but won’t know until then if we protected enough, too much or too little – two of these outcomes we will be thanked for, the other held to blame.
“More marine park reserves, means more fish for divers, for snorkellers, for fishermen, for the health of the reefs. This has been proven by the Department of Environment studies over the last 25 years,” the statement read. The tourism association also pointed out that drawing boundaries outlining expanded marine parks were not enough, that there must also be resources assigned “to enforce and protect what is at risk”.
“Expansion of the marine parks, must include the enforcement provisions to safeguard our environment from poachers and violators,” the association said.
Feedback received during the consultation period for the draft proposals for expanding protection for marine life in Cayman will be incorporated into the proposals. Although there has been support from many quarters in Cayman for the proposals, there has also been some vocal opposition from fishermen who say the proposed restrictions will reduce their catches.
Protected marine parks were first established in Cayman 25 years ago, with the intention of safeguarding local coral reefs and fisheries.
The parasite attached near this fish's eye makes it harder for it to get away from predators
The parasite attached near this fish's eye makes it harder for it to get away from predators (Dominique Roche)
Parasitic crustaceans cause significant drag on reef fish impeding their ability to swim fast and stay safe, researchers have found.
Coral-reef-dwelling fish like the bridled monocle bream (Scolopsis bilineatus) have a tough time keeping safe, says Binning.
Such small fish have to swim fast just to stay in one place as they are pushed this way and that by currents and waves in the shallow reef waters.
"You get areas on the reef where the water is moving quite dramatically," says Binning.
She says being able to swim fast is important if they want to stay hidden from predators in the coral reef, or if they need to actively escape a chasing predator.
But such fish also often have to contend with a relatively large parasitic crustacean called Anilocra nemipteri stuck on its head.
The parasite can be 15 per cent of the fish's total body length and hang around for up to two years, says Binning. It is presumed to suck the blood of the host and is related to another parasite that eats out the tongues of fish, says Binning.
Binning and colleagues investigated the impact of Anilocra nemipteri on Scolopsis bilineatus's physiology and on its streamlining and swimming performance.
Water is a lot denser than air, says Binning, so anything stuck on the fish can easily increase drag and slow it down.
The researchers collected fish from reefs around Lizard Island on the Great Barrier Reef and set up experiments designed to separate out the impact of the parasite on physiology and streamlining.
Binning and colleagues set up an underwater treadmill - a loop-shaped tank with a propeller in it that generates a current of known speed.
Because fish tend to swim against a current to stay in one place, this enabled Binning and colleagues to measure the speed the fish were swimming.
They were also able to measure the amount of oxygen the fish were consuming, which indicated how much energy the fish were using.
Binning and colleagues found that parasitised fish had a higher resting metabolic rate than non-parasitised fish.
"Even for doing nothing they need more energy use to survive," says Binning.
These fish also used more oxygen when swimming and were not able to swim as fast as non-parasitised fish, she says.
Binning says the parasite reduced the maximum swimming speed of the fish by half a body length per second.
The researchers then tested what happened when they stuck a plastic 'parasite' on a healthy fish.
"We glued on a fake parasite that had approximately the same weight, length and width as the normal parasite that you see in the wild," says Binning.
They found this had no effect on the fish's resting metabolic rate, but had the same effect on the fish's swimming abilities as a real parasite.
The plastic parasite reduced the fish's maximum swimming speed and caused it to consume more oxygen when swimming.
"They were really struggling, just as the fishes that had the parasite were," says Binning.
Levels of parasitism
Sampling shows that overall about 4 per cent of Scolopsis bilineatus around Lizard Island are parasitised by the crustacean.
Among juveniles this rises to about 10 per cent, says Binning, and in some habitats up to about 30 per cent of adult fish are parasitised.
Binning says it will be important to find out why fish in some habitats are more likely to parasitised. It could be, for example, because the water is warmer or contains more nutrients, she says.
Según advirtió el Programa de las Naciones Unidas para el Medio Ambiente (PNUMA) en un informe divulgado ayer, el derretimiento del permafrost puede causar un mayor calentamiento global del estimado hasta hoy.
El documento señala que hasta el momento, las proyecciones de calentamiento del planeta no habían tomado en cuenta que la capa del suelo que se encuentra congelada permanentemente en las regiones polares –o permafrost– ha empezado a fundirse y señaló que esto puede acelerar el cambio climático.
El PNUMA explicó que al derretirse, el permafrost causará grandes emisiones de dióxido de carbono y metano, lo que alteraría los ecosistemas y causaría daños graves de infraestructura dado que el suelo sería cada vez más inestable.
Ante este panorama, el estudio insta al panel intergubernamental sobre cambio climático a evaluar la magnitud del fenómeno y a crear redes nacionales de monitoreo.
Además, exhorta a elaborar planes de adaptación para afrontar los impactos de las emisiones.
El permafrost cubre casi la cuarta parte del hemisferio norte y contiene 1.700 gigatones de carbón, dos veces la cantidad que hay actualmente de ese elemento en la atmósfera.
El 2011 es el noveno año con las temperaturas más altas desde que comenzaron a registrarse globalmente.
El personal encargado de las zonas costeras australianas aseguró que el alga no es tóxica. Diferentes playas de Australia fueron cerradas debido al brote de una especide de alga que tiñe el agua de rojo.
La especie conocida como Noctilluca scintillans pintó de rojo las playas de Clovelly y Gordons Bay, además de la mundialmente conocida, Bondi, en la costa de Sydney.
El alga tiende a proliferar en situaciones de climas extremos, sobre todo cuando se trata de una temperatura cálida combinada con lluvias abundantes, de acuerdo con los expertos.
"La temperatura del agua incrementó de 19 a 21 grados centígrados rápidamente y eso provocó un aumento substancial de las algas en las playas" dijo a la cadena CNN el guardacostas Bruce Hopkins.
La especie se caracteriza por disminuir el oxígeno del agua, lo que provoca la muerte de los peces en el área. El personal encargado de las zonas costeras asegura que el alga no es tóxica, sin embargo, puede provocar irritaciones en la piel y en los ojos, por lo que prefirieron cerrar las playas al público.
Leatherback turtle (Dermochelys coriacea)
Editor’s note: this post is courtesy of Sea Turtles 911, a nonprofit dedicated to rescuing sea turtles in the South China Sea.
Chinese fishermen have reported the death of a Leatherback sea turtle (Dermochelys coriacea) on Hainan Island, China. The turtle was caught as by-catch by a fishing vessel on November 24 and held in a concrete saltwater pool. Leatherback turtles are adapted to the open ocean, so they swim continuously against tank walls since these pelagic turtles do not recognize physical barriers.Contact with the rough surface caused tissue abrasions, bone exposure, and infection on the Leatherback’s nose, flippers, and ridges along the back of its shell.
When the turtle’s finger bones protruded from its skin and began falling out, the fisherman housing the turtle reportedly searched online for information on how to care for Leatherbacks in captivity. After failed attempts at restoring its health, the fisherman contacted Sea Turtles 911, the American based sea turtle conservation organization that operates in China. Medical volunteers experienced in sea turtle rescue and rehabilitation immediately arrived on the scene to help, but upon examination of the Leatherback her condition was terminal.
Sea Turtles 911 Founding Director Frederick Yeh describes, “She was very weak, very far gone. Despite the emergency treatments we performed, there was little we could do at that point to save her. Leatherbacks are particularly vulnerable to injury in captivity, and the fisherman contacted us much too late. The waste of such a precious life is heartbreaking.”
The turtle was a female weighing approximately 500 pounds (227 kg) and measured 5 feet (1.5 meters) in length. The local Hainan name for Leatherbacks literally translates into ‘tire turtle’ due to their black, rubbery bodies resembling the appearance of a tire. Leatherback sea turtles are listed as critically endangered on the IUCN Red List of Endangered Species, primarily due to direct harvest by humans who take their eggs from nesting beaches, or kill the turtles for their meat, leathery skin, and for oil extraction. Leatherbacks have no cultural significance in Chinese trade, unlike Green (Chelonia mydas) and Hawksbill (Eretmochelys imbricata) sea turtles, which incur high prices in the illegal market. However, fishermen will bring by-catch Leatherbacks onto land and attempt to sell them.
It is unknown how many Leatherback sea turtles are bought and sold illegally in China, or what they do in the surrounding waters, but the frequency of local fishermen reporting ‘tire turtle’ sightings suggests possible migration routes past the island. Yeh is determined to find out for certain, “This beautiful, rare sea turtle’s death cannot be in vain. We need more resources to help us find out what the Leatherbacks are doing here, and how many are being taken by local fishermen. Only then will we be properly equipped to protect them.
Read more: http://www.care2.com/causes/leatherback-turtle-dies-in-china.html#ixzz2Dgg9dWc7Source: http://www.care2.com/causes/leatherback-turtle-dies-in-china.html
Photo by Terry Lilley
By Kim Murphy, Los Angeles Times
HANALEI, Hawaii — When compiling a list of places that may be described as paradise, Hanalei Bay on the rugged north shore of the island of Kauai surely qualifies.
The perfect crescent bay, rimmed by palm trees, emerald cliffs and stretches of white sand, has always had a dreamy kind of appeal. It was on these shores that sailors in the movie "South Pacific" sang of the exotic but unattainable "Bali Ha'i."
The problem is what lies below the surface of the area's shimmering blue waters.
Since June, a mysterious milky growth has been spreading rapidly across the coral reefs in Hanalei and the surrounding bays of the north shore — so rapidly that biologist Terry Lilley, who has been documenting the phenomenon, says it now affects 5% of all the coral in Hanalei Bay and up to 40% of the coral in nearby Anini Bay. Other areas are "just as bad, if not worse," he said.
The growth, identified by scientists at the U.S. Geological Survey as both a cyanobacterial pathogen — a bacteria that grows through photosynthesis — and a fungus, is killing all the coral it strikes, and spreading at the rate of 1 to 3 inches a week on every coral it infects.
"There is nowhere we know of in the entire world where an entire reef system for 60 miles has been compromised in one fell swoop. This bacteria has been killing some of these 50- to 100-year-old corals in less than eight weeks," Lilley said. "Something is causing the entire reef system here in Kauai to lose its immune system."
The discovery of the new coral disease is only one of a number of ailments afflicting nearly all the world's coral reefs, which are threatened by poisonous runoff, rising oceans, increasingly acidic waters and overfishing.
But this one could jeopardize a multibillion-dollar tourist industry in Hawaii, which depends on the stunning displays of color and wildlife for divers and snorkelers. That is especially true along the beaches of Kauai, where the north shore with a few exceptions remains a place of pristine natural beauty.
"It's very alarming," said Wendy Wiltse of the federal Environmental Protection Agency in Honolulu. "All of us are concerned about it. We want to do more. Part of the problem is we don't know what to do, especially in the case of a disease that's spread by a pathogen. It's not like we can put antibiotics in the ocean."
Researchers at the U.S. Geological Survey reported last week that the disease had reached epidemic proportions. "This is the first time a cyanobacterial/fungal disease on this scale has been documented in Hawaiian corals," Thierry M. Work, USGS wildlife disease specialist, said in an analysis released Wednesday.
Scientists say there are no signs so far that the bacteria killing the coral are dangerous to humans or wildlife, though they are conducting further tests.
But Lilley, who does not hold a graduate degree but dives daily around the reefs all across the north shore, said he has documented a large number of cases of black-and-white toby fish feeding near diseased corals that turned completely black, lost their fins and died.
He has also videotaped a sea turtle, seen feeding on seaweed growing out of an infected coral, whose eyes seemed to have rotted away. When Lilley saw it, the creature was bumping blindly into the reef in an attempt to find food.
The disease was first spotted around Hanalei in 2004, but "at very low levels," and is the fourth coral disease outbreak documented in the state since 2009, said Greta Aeby, a coral expert with the University of Hawaii Institute of Marine Biology who has been working with Lilley to document the phenomenon.
"Hawaii's reefs are in decline. They are faced with the chronic stressors of land-based pollution, overfishing and human use. The reefs have been dealing with these problems for years, and are starting to show the signs," she said. "We need to help people understand the seriousness of the situation before it is too late."
Lilley said the rapid growth of the coral disease this year followed two years of heavy sedimentation traveling down the Hanalei River, which he believes could be traced to development upstream and heavy rains.
Thick mud often coated the corals, he said, and studies paid for by a community group showed high levels of heavy metals in the water — studies that were dismissed by the state Department of Health, which said such metals were natural to the volcanic soil of Hawaii.
Wiltse said other studies had shown high levels of sewage-related bacteria in the Hanalei River, probably because the town of Hanalei has no sewer system and homes are connected to cesspools and septic systems.
"There have also been some studies of sediment and nutrients, primarily in Hanalei River, and during rain events, there is excessive suspended sediment in the river, exceeding water quality standards," she said. "I've seen plumes extending into the ocean. I've seen sediment settling on corals."
But is that what led to the recent outbreak of a bacterial infection? No one can say. Lilley theorizes that pollution could have weakened the coral and made it more susceptible to a bacterial outbreak, but can't be certain.
In a preliminary review in September, the USGS said the general health of coral reefs along Kauai's north shore was poor. "The overall picture was one of a severely degraded reef impacted by sediments and turf algae," the agency's report said, with symptoms of "chronic stress."
Work, the USGS scientist, said the loss of coral meant a danger of losing the fish, turtles and various invertebrates that depend on it for sustenance and shelter.
"A lot of people come to Hawaii in part because it is a beautiful place both on land and in the water, so coral reefs are a resource with tangible economic value," he said. "Like it or not, ecosystem health is closely intertwined with human and animal health."
En los últimos 27 años, la Gran Barrera de Coral de Australia se redujo a la mitad.
Un equipo de científicos descubrió en Australia un método para combatir a las estrellas de mar que devoran corales en los mares de medio mundo. Es un combinado de proteínas utilizado en los laboratorios para hacer crecer colonias de bacterias que mata en menos de 24 horas a la Acantáster púrpura, conocida como corona de espinas y voraz depredadora de corales.
“Un brote de coronas de espinas puede destruir entre el 40 al 90 por ciento de los corales. En los últimos 50 años, han causado un gran daño”, dijo en un comunicado Jairo Rivera Posada, un científico colombiano nacionalizado australiano que forma parte del equipo de la Universidad James Cook que realizó el descubrimiento.
Estas estrellas marinas, cuya hembra produce hasta 100 millones de huevos al año y de adultas llegan a medir 40 centímetros, se alimentan de los corales. Un ejemplar puede comer cada día su peso en coral y, si hay una colonia de 50.000 a 60.000, entonces “el efecto es devastador”, explicó Rivera.
El investigador se encontraba con su profesor, Morgan Pratchett, en la isla Lizard, en el norte de la Gran Barrera de Coral, cuando pensó que cultivar bacterias Vibrio podía servir para combatir a las coronas de espinas. Con esta idea en mente y la colaboración de Pratchett, recogieron algunas coronas de espinas para analizar las bacterias de sus sistemas digestivos.
Los científicos elaboraron una sustancia a base de carbonatos y proteínas extraídas de tejidos animales, principalmente de ganado. El componente probó ser mortal para las acantáster púrpura en menos de 24 horas y además infectaba a otros ejemplares de la misma especie que estaban próximos al sujeto inoculado, según los ensayos llevados a cabo en el Centro de Excelencia de Estudios de Arrecifes de Coral de la Universidad James Cook (CoECRS, según sus siglas en inglés).
Rivera admitió que si bien el método es muy barato, consume mucho trabajo porque cada estrella requiere que se le inyecte la sustancia en cuatro lugares distintos.
En las décadas de 1960 y 1980 se registraron plagas de este tipo de invertebrado en la región del Indo-Pacífico y los expertos temen una reaparición con un impacto desolador en la Gran Barrera de Coral, declarada Patrimonio de la Humanidad por la Unesco en 1981. Según un estudio publicado la semana pasada por científicos australianos, en los últimos 27 años esta región perdió más de la mitad de sus corales. La corona de espinas es responsable del 42% de los daños.
Rivera dijo que la protección de los corales no debe limitarse al control de la población de acantáster púrpura e instó a la humanidad a mejorar la calidad de las aguas marinas. Las larvas de la corona de espinas pueden hallar alimentos cuando hay mucha sedimentación, se usan pesticidas o se descargan los residuos de los desagües directamente en el mar.
Pratchett indicó que la nueva sustancia es muy prometedora, pero aún falta realizar muchas pruebas para asegurarse de que no ponga en peligro a otras especies ni el ecosistema de la Gran Barrera de Coral.
Cold-water corals face an uncertain future as increasing CO2 in the atmosphere changes the chemistry of our oceans. Laura Wicks set sail on the Changing Oceans Expedition to find out how these amazing animals are likely to fare.
Hidden deep in all the world's oceans are the vast mounds and reefs of cold-water corals. They grow much more slowly than their tropical counterparts but can still extend over huge areas: reefs of Lophelia pertusa off Norway cover around 2000km2 - more than tropical reefs in the Seychelles, Belize or Mozambique. The corals build their skeletons from calcium carbonate dissolved in the seawater, creating complex 3D structures that persist even after the animal itself has died. These skeletons support thousands of species, including many that we eat.
But the life of these hidden corals is under threat.
The amount of CO2 in the atmosphere has increased exponentially since the Industrial Revolution and much of it is dissolving into the oceans, slowly increasing the acidity of seawater. The pH of the sea is currently about 8.1, but this is predicted to drop by about 0.3 pH units by 2100. It doesn't sound like much, but this small change can have huge implications for marine organisms that rely on calcium carbonate, like corals, shell-producing animals and calcareous algae. This is because the increasing concentration of dissolved CO2 in the oceans decreases the carbonate saturation of the water, so there is less carbonate available for coral skeletons and shells.
This acidification of the oceans, often referred to as 'the other CO2 problem', may be the biggest threat facing marine calcifying organisms today.
In May 2012, I set sail for the North Atlantic on the RRS James Cook, part of an international team of scientists on the Changing Oceans Expedition. Our mission was to examine the potential impact of ocean acidification and warming on cold-water coral reefs and the creatures they support.
In our four weeks at sea we visited a range of cold-water coral sites, from the 'shallow' reefs of Mingulay in the Outer Hebrides (around 130m deep), dominated by Lophelia pertusa, to the Logachev Mounds, west of Ireland; nearly 1000m deep and spectacular with both Lophelia pertusa and Madrepora oculata. We don't know a great deal about either species of coral, or the ecosystems they form, because they are so inaccessible - you can't just dive in and explore them like you can in the tropics.
Before we could even think about collecting samples we had to find the reefs. To do this we used advanced acoustic techniques, such as multibeam and sidescan sonar, that use sound waves to create an image of the seabed from which we could pick out possible mounds of coral. The next step was to send down our robot, the Remotely Operated Vehicle (ROV) Holland I, to take a closer look.
During each ROV dive the excitement in the lab was palpable. The ROV's high-definition cameras beamed up spectacular images of the reefs beneath us. Fish darted across the screen and unusual sponges and crabs came into view, causing a buzz as we tried to work out exactly what they were.
But we weren't just there to watch. As part of 'Team Coral', I carried out short-term experiments to see what effect ocean warming and acidification have on the growth and overall health of the corals. Using samples carefully collected by the ROV's robotic arms, we kept Lophelia pertusa and Madrepora oculata in specially designed tanks for the duration of the cruise. We manipulated the temperature and CO2 levels in these 'mini-oceans' to mimic one possible set of future conditions, in this case a 3°C increase in temperature and a near-doubling of atmospheric CO2. We then measured the respiration and growth rates of the corals over three weeks. My team-mates looked at how other aspects of the corals' biology responded to their changing environment, including microbial communities and protein expression. All of an animal's biological processes, such as growth and respiration, are controlled by proteins, so changes in the concentration of various proteins give us a clue as to how processes like calcification may respond to increased temperature and ocean acidification in the future.
Along with longer-term experiments under way at Heriot-Watt University, these will help us to work out how the corals will respond to global climate change - whether they can adapt, or whether ultimately it will be impossible for them to survive.
Alongside the ROV campaign, a host of other activities took place out at sea. One was the deployment of the CTD and SAPS. CTD stands for conductivity, temperature and depth, which this particular instrument measures at the bottom of the ocean. Attached to the CTD frame we had a SAPS - Stand Alone Pumping System - which is a big pump with a filter and timer.
We use the SAPS to look at the amount of particulate organic carbon (coral food) that is reaching the reefs. When it reaches the seabed the pump switches on and records how much water flows through its filters, which capture the organic carbon. Back in the lab, we analyse the amount of carbon on the filters and the water flow, to calculate how much food the corals have access to. Combined with surveys of the reef and CTD data, this information can help us understand why the corals live where they do, and how any future changes in climate and currents may affect these ecosystems.
Four weeks at sea passed by in a flash, and everyone on board collected a wealth of information. Now we're all back on dry land, it's time to process samples, extract data and try to understand what the future holds for these cold-water creatures as our oceans change.
Los cambios en la temperatura y el volumen del hielo o nivel del mar están estrechamente acoplados con un retraso de tiempo de respuesta de tan sólo unos pocos siglos al comparar las fluctuaciones de volumen de hielo con reconstrucciones de temperaturas polares de Groenlandia y la Antártida, según un nuevo estudio publicado en 'Nature'. Esta relación era desconocida hasta el momento y revela una respuesta muy rápida entre la temperatura global y el volumen de hielo/nivel del mar, lo que podría dar lugar a un aumento del nivel del mar de más de un metro.
Dirigidos por Eelco Rohling, profesor de Oceanografía y Cambio Climático en la Universidad de Southampton (Reino Unido), los investigadores también descubrieron que los períodos de hielo extenso se caracterizaron siempre por cambios muy rápidos, del orden de uno o incluso dos metros del nivel del mar por siglo.
El equipo internacional de científicos desarrolló un nuevo método de datación del registro RSL (nivel relativo del Mar Rojo) mediante el uso de datos radiométricos mediterráneos (Uranium-series) que datan los depósitos de cuevas. Esto proporcionó una escala de tiempo mucho mejor para el registro RSL, con lo que el equipo fue capaz de aplicar el nuevo método de datación largo de todo el ciclo glacial pasado (150.000 años), obteniendo un registro continuo sin precedentes del nivel del mar con un excelente control independiente de la edad.
"Posiblemente, los cambios de temperatura del Antártico reflejan los cambios fundamentales subyacentes de temperatura global que impulsaron los cambios de volumen de hielo, mientras que el registro de las temperaturas de Groenlandia representa principalmente una respuesta de la temperatura regional a los volúmenes de hielo cambiantes. Estos son indicios intrigantes en aspectos fundamentales de la respuesta del Sistema de la Tierra al cambio climático, que merecen una investigación más a fondo", destaca Rohling.
"Lo que es nuevo aquí es que nuestra datación de los sedimentos marinos es mucho más directa. Esto nos da perfiles de edad mucho más precisos para las secuencias sedimentarias, que a su vez proporciona información valiosa sobre la forma en que el sistema de la Tierra ha funcionado en el pasado", añade el coautor Christopher Bronk Ramsey, de la Universidad de Oxford