domingo, 16 de diciembre de 2012

Coral sperm bank offers last ditch hope for restoring health of reefs

Coconut Island, HI - Just before sunset, on the campus of the Hawaii Institute of Marine Biology, Mary Hagedorn waited for her mushroom corals to spawn.

As corals go, Fungia is fairly reliable, usually releasing its sperm and eggs two days after the full moon, but this time they were late.


Eventually, as Dr Hagedorn and her assistant watched, one coral tightened its mouth and seemed to exhale, propelling a cloud of sperm into its bath and the water bubbled like hot oatmeal.


A reproductive physiologist with the Smithsonian Institution, Dr Hagedorn, 57, is building what is essentially a sperm bank for the world's corals. She hopes her collection - gathered in recent years from corals in Hawaii, the Caribbean and Australia - will someday be used to restore, and even rebuild, damaged reefs.


She estimates that she has frozen 1 trillion coral sperm, enough to fertilise 500 million to 1 billion eggs. In addition, there are 3 billion frozen embryonic cells; some have characteristics of stem cells, meaning they may have the potential to grow into adult corals.


Dr Hagedorn's collection is the only one of its kind. While corals can reproduce asexually - that is, fragments of coral can grow into clones of their parents - Dr Hagedorn points out that only sexual reproduction maintains genetic diversity within populations, and with it a species' capacity to survive and adapt to change.


For corals, the number of likely partners is shrinking. As climate change warms the oceans, corals are becoming more vulnerable to disease and bleaching.


In recent years, bleaching events have grown from local curiosities to global phenomena and, in some cases, are so severe and long-lasting that the corals cannot recover. Meanwhile, rising carbon dioxide levels are acidifying the oceans, inhibiting the growth of coral skeletons and weakening the bones of reefs.


In the central and western parts of the Pacific Ocean the extent of living coral is thought to have shrunk by half between the early 1980s and 2003. If this decline continues, almost all of the world's reefs will be on their way to oblivion by 2050.


Dr Hagedorn supports traditional conservation strategies, such as marine refuges, but is preparing for their failure. While she freezes coral sperm and eggs for future use, colleagues are refining techniques for raising coral in captivity and for reintroducing young corals to their natural habitats.


But she and her colleagues have to struggle to raise money for her efforts, which are often seen as a distraction from the more immediate job of habitat protection.


Last northern autumn, she and a group of colleagues travelled to Australia at the invitation of the Australian Institute of Marine Science. Using techniques developed by Dr Hagedorn, they froze sperm and cells from colonies of Acropora tenuis and Acropora millepora, two of the roughly 400 coral species native to the Great Barrier Reef.

viernes, 14 de diciembre de 2012

Researchers monitor red tides in Chesapeake Bay

Gloucester Point, VA — Researchers at the Virginia Institute of Marine Science continue to monitor the algal blooms that have been discoloring Chesapeake Bay waters during the last few weeks. These "red tides" occur in the lower Bay every summer, but have appeared earlier and across a wider area than in years past, likely due to last winter's warmth and this summer's heat.

Red tides are caused by dense blooms of tiny marine plants called algae that contain reddish pigment. Algae are normal components of all aquatic environments, but can produce what is known as a "harmful algal bloom" or "HAB" when they bloom in significant numbers and generate toxic byproducts. HABs can be harmful to both marine organisms and human health.


Professor Kim Reece, a member of Virginia's Harmful Algal Bloom Task Force, is the focal point for HAB research and monitoring at VIMS. Reece, fellow VIMS professor Wolfgang Vogelbein, and other colleagues at VIMS partner with representatives from the Virginia Department of Health, the Marine Resources Commission, the Department of Environmental Quality, and Old Dominion University to track the appearance of algal blooms within Virginia waters and to determine whether the bloom organisms pose any threat to marine life or human health.


There is currently no evidence of harm from the recent blooms, which were first observed in early to mid-July. Study of samples taken in the York River near VIMS' Gloucester Point campus show that they comprise dense aggregations of Cochlodinium polykrikoides, a single-celled marine dinoflagellate.


Reece says "Blooms of this and closely related species may harm oyster larvae and other marine life, and are associated with fish kills and economic loss in Japan and Korea, but we've had no reports of any of these effects in local waters this year." Fish and crab kills reported in the Bay during Cochlodinium blooms in previous years are likely due to low levels of dissolved oxygen, which are associated with blooms of many different species and occur when the algal cells die, sink, and decay.


Virginia residents who have observed a patch of water that is colored red or mahogany and are concerned should contact Virginia's toll-free Harmful Algal Bloom hotline at (888) 238-6154.


Algal blooms are not uncommon in lower Chesapeake Bay during the spring and summer. Algae respond to the same conditions that encourage plant growth on land, and thus are most likely to form blooms when waters are warm and nutrient rich. Excess nutrients from farms and yards, sewage treatment plants, and the burning of fossil fuels are one of the biggest challenges facing the Bay.


"There are three main ingredients for an algal bloom," explains Reece. "Warm waters that favor rapid growth of algal cells, abundant nutrients to fertilize that growth, and wind and tidal-driven currents to confine the cells into a dense aggregation. Our recent heat and rains provide ideal conditions for bloom formation, so we'll continue to monitor whether the ongoing blooms become a cause for any concern."


Real-time monitoring of algal blooms is not an easy task, as it involves developing and applying DNA tests to rapidly identify -- from among a huge variety of mostly benign microorganisms -- the particular algal species that have been observed to produce toxins. Development of these molecular DNA assays is a prime focus of Reece's research at VIMS.


Monitoring also requires daily collection of water samples from all across lower Chesapeake Bay. Analysis of these samples at VIMS shows that Cochlodinium is currently blooming in the York, James, Elizabeth, and Lafayette rivers; Mobjack Bay; and near the mouth of the Bay in the vicinity of the Hampton Roads Bridge Tunnel.

miércoles, 12 de diciembre de 2012

Divided dolphin societies merge for first time

Sydney, NSW - Two become one: the unification of these two socially distinct groups of bottlenose dolphin demonstrates the intelligence and social adaptability of the species.

A unique social division among a population of bottlenose dolphins in Australia's Moreton Bay has ended, according to a new study. The dolphins lived as two distinct groups that rarely interacted, one of which foraged on trawler bycatch.

But scientists think that a ban on fishing boats from key areas has brought the two groups together. They believe these socially flexible mammals have united to hunt for new food sources. The findings are published in the journal Animal Behaviour.

Bottlenose dolphins have large brains and quickly learn new behaviours. Using a wide range of sounds to communicate with other members of the group, or "pod", they have been observed showing remarkable individual and social intelligence:

The Moreton Bay dolphins were thought to be the only recorded example of a single population that consisted of groups that were not associating with each other in a split dubbed "the parting of the pods". But since the study that discovered the rift, trawlers have been banned from designated areas of the bay leading to a 50% reduction in the fishing effort.

A key area of the bay to the south, where the social split was observed by the previous study, has been protected. The changes gave scientists a unique opportunity to observe the adaptability of dolphin society. The "trawler" dolphins from Moreton Bay had previously fed on the bycatch from boats while the "non-trawlers" found other sources of food.

"There's never been really any experiments looking at social structure... where you can compare what it was like before and what it is like now," said Dr Ina Ansmann, marine vertebrate ecologist, University of Queensland, and the study's lead author.

Analysing how the population interacted before and after trawling meant the team could assess how the dolphins' social network had changed. "The dolphins had basically re-arranged their whole social system after trawling disappeared so they're now actually interacting again," Dr Ansmann told BBC Nature.

The scientists identified individual dolphins by the marks on their dorsal fin and recorded which animals were associating with which.

"Each dolphin has small injuries like nicks and notches, cuts and things like that on the fin so they all have a very unique looking dorsal fin." This technique meant that Dr Ansmann could observe changes in behaviour, in some cases down to the individual dolphins which had been studied in the 1990s to reveal the original division.

The "trawler" dolphins of Moreton Bay benefited from the bycatch thrown back from fishing boats "Presumably they're sharing information, co-operating and things like that." One of those males is now fully integrated into a single community.

Dolphins operate in what is called a fission-fusion society, forming groups and then splitting up to form different groups. Through complex communication and social intelligence, bottlenose dolphins often work as a team when hunting for food and Dr Ansmann believes this may be what lies behind the unification.

"When relying on natural food sources I guess it's more important for them to interact with others, or to learn from others, or to co-operate with others to get to these food sources," she said. The results suggest that a flexible social structure may be an important factor in how dolphins exploit a wide range of resources in the marine environment.

lunes, 10 de diciembre de 2012

A whale of a hearing system

New York, NY - Kina, a false killer whale, was the focus of a study about how marine mammals hear. A group of scientists led by marine biologist Paul Nachtigall discovered whales can "close" their ears, decreasing their sensitivity to loud noises underwater.

Scientists have long known that man-made, underwater noises – from engines, sonars, weapons testing, and such industrial tools as air guns used in oil and gas exploration – are deafening whales and other sea mammals. The Navy estimates that loud booms from just its underwater listening devices, mainly sonar, result in temporary or permanent hearing loss for more than a quarter-million sea creatures every year, a number that is rising.


Now, scientists have discovered that whales can decrease the sensitivity of their hearing to protect their ears from loud noise. Humans tend to do this with index fingers; scientists haven't pinpointed how whales do it, but they have seen the first evidence of the behavior.


"It's equivalent to plugging your ears when a jet flies over," said Paul E. Nachtigall, a marine biologist at the University of Hawaii who led the discovery team. "It's like a volume control."

The finding, while preliminary, is already raising hopes for the development of warning signals that would alert whales, dolphins and other sea mammals to auditory danger.

Peter Madsen, a professor of marine biology at Aarhus University in Denmark, said he applauded the Hawaiian team for its "elegant study" and the promise of innovative ways of "getting at some of the noise problems." But he cautioned against letting the discovery slow global efforts to reduce the oceanic roar, which would aid the beleaguered sea mammals more directly.


The noise threat arises because of the basic properties of seawater. Typically, light can travel for hundreds of feet through ocean water before diminishing to nothingness. But sound can travel for hundreds of miles.


The world's oceans have been getting noisier as companies and governments expand their undersea activities. Researchers have linked the growing racket to deafness, tissue damage, mass strandings and disorientation in creatures that rely on hearing to navigate, find food and care for their young. The danger has long been a political football.


In 2008, the Supreme Court heard a lawsuit by the National Resources Defense Council against the Navy over ocean noise; the court ruled that naval vessels had the right to test sonar systems for hunting submarines. But environmentalists saw a tacit victory in getting the nation's highest court even to consider the health of sea mammals in a debate over national security.


The latest development took place at a research facility off Oahu – at an island where the opening shots of "Gilligan's Island" were filmed. Scientists there are studying how dolphins and toothed whales hear. In nature, the mammals emit sounds and listen for returning echoes in a sensory behavior known as echolocation. In captivity, scientists taught the creatures to wear suction-cup electrodes, which revealed the patterns of brainwaves involved in hearing.


The discovery came in steps. First, Nachtigall and his team found that the animals could adjust their hearing in response to their own loud sounds of echolocation, mainly sharp clicks. The scientists then wondered if they could also protect their ears from incoming blasts.

The team focused on a false killer whale named Kina and sought to teach her a conditioned behavior similar to how Pavlov taught dogs to salivate upon hearing a bell.

First, the scientists played a gentle tone repeatedly. Then they followed the gentle pulse with a loud sound. After a few trials, the warning signal alone caused Kina to decrease the sensitivity of her hearing.


"It shows promise as a way to mitigate the effects of loud sounds," said Nachtigall, founding director of the Marine Mammal Research Program at the University of Hawaii. "People are generally very excited about it."


In May, Nachtigall and his colleagues presented the findings to acoustic scientists and groups meeting in Hong Kong, including the Acoustical Society of America. The team cited the protective deafening as a potential way to help sea mammals cope with noisy blasts from naval sonars, civilian air guns and other equipment.

In the future, the team plans to expand the research to other species in captivity and ultimately to animals in the wild.

"We have a problem in the world," Nachtigall said of the oceanic roar. "And we think the animals can learn this response very rapidly."

Scientists unconnected to the mammal research called it important.

"It's a big deal," said Vincent M. Janik, a prominent marine biologist at the University of St. Andrews in Scotland. In an email, he said it revealed a rare ability among the planet's creatures.

Carl Safina, president of the Blue Ocean Institute, a conservation group in Cold Spring Harbor, N.Y., called the discovery a potential window into what sea mammals may already do on some occasions to protect their hearing.

"I've sometimes wondered why these high intensity sounds don't cause problems all the time," he said in an interview. "Maybe it's that, once the animals hear something very loud, they can adjust their hearing – dial it down and protect themselves."


Scientists say the extraordinary hearing of sea mammals evolved to compensate for poor visibility beneath the waves and to take advantage of the unique qualities of seawater. Sound travels five times faster than in air and undergoes far less diminishment.

The heads of whales and dolphins are mazes of resonant chambers and acoustic lenses that give the animals not only extraordinary hearing but complex voices. The distinctive songs of humpback whales appear to be sung exclusively by males seeking mates.

In recent decades, scientists have linked the human cacophony to reductions in mammalian vocalization, which suggests declines in foraging and breeding. And the problem is poised to get worse: In May, the Navy disclosed draft environmental impact statements (Atlantic and Pacific operations) that said planned expansions could raise the annual hearing losses among sea mammals to more than 1 million.


Zak Smith, a lawyer with the Natural Resources Defense Council, recently called the new estimates "staggering." A question of science, Nachtigall said, is whether the levels of protective deafening found in Kina can be increased. The team plans to study the auditory response in such species as bottlenose dolphins and beluga whales before trying it on wild populations.


The big political hurdle is financing, he said. Federal support for the sea mammal research has declined in recent years, and industry is only starting to show interest in the finding.


"I'm pulling in money where I can," he remarked. Nachtigall said the research was costly because sea mammals need high levels of care.

But he called it revealing and rewarding. "When it comes to whales and sound," Nachtigall said, "we're just starting to understand."

lunes, 22 de octubre de 2012

A 10-fold rise in Marine Protected Areas has been recorded over a decade.

Hyderabad, UK - A 10-fold rise in Marine Protected Areas has been recorded over a decade.

A report to a UN meeting on biodiversity in Hyderabad reports that more than 8.3 million sq km - 2.3% of the global ocean area - is now protected.

The percentage is small but the rapid growth in recent times leads to hope that the world will hit its target of 10% protected by 2020.

This would have looked most unlikely prospect just a few years ago.

The aspiration was agreed by the Convention on Biological Diversity in 2004 with a target date of 2012. Progress was so slow at first that the target was slipped to 2020 - with some researchers forecasting it would not be reached until mid-century.

But recently there have been huge additions - like Marine Protected Areas (MPAs) in the UK-controlled Chagos archipelago and US-controlled uninhabited territories in the mid-Pacific.

The Cook Islands recently announced a 1.1 million sq km MPA - that is four times the area of the UK land mass. New Caledonia's is even bigger - 1.4 million sq km.

Australia has added a further 2.7 million sq km to its listing of the Great Barrier Reef. Now 28 countries have designated MPAs of more than 10%.

But these statistics may not be quite so impressive as they appear as most of them are far distant from people who would be likely to over-exploit them.

And a recent paper on the demise of the Barrier Reef demonstrates that declaring an area protected does not necessarily shield it from distant influences like over-nutrification.

Mark Spalding from the Nature Conservancy, lead author of the report, told BBC News: "This is great news in the sense that the prospect looked so hopeless until recently. We really should manage to meet the 10% target now.

"But we have to ask whether the targets in themselves are enough - or whether governments need to be smarter to ensure that they're protecting the very most important areas.

"I don't want to knock any of the MPAs but some appear to be easy wins, where you could stick a pin on a map and maybe send a patrol vessel. We need more than that."

Dr Spalding said it was vital now for nations to concentrate efforts on MPAs near heavily-populated coastlines where marine resources were most at risk.

The UK government has been accused of dragging its feet after postponing by a year the introduction of MPAs around the coast of England.

sábado, 20 de octubre de 2012

Passionate opinions voiced at NOAA hearing on 'taking' of beluga whales

Silver Spring, Md. - Passionate statements from aquarium officials and environmental activists alike over the importation of beluga whales resounded in a crowded but quiet meeting room at the National Oceanic and Atmospheric Administration Science Center Friday.
The issue at hand was the Atlanta-based Georgia Aquarium's application for a permit to import 18 beluga whales from Russia. While the Georgia Aquarium is seeking to import the whales, they would go to multiple destinations - possibly including several SeaWorld locations as well as Mystic Aquarium, which currently houses four beluga whales, also known as white whales.
The Marine Mammal Protection Act of 1972 prohibits the "take or import" of marine mammals but includes an exception for animals kept for educational public display or scientific research. NOAA officials held Friday's hearing as part of the process of gathering public comment before making a final decision, which is expected to be issued early next year.
NOAA regulations require only a 30-day public comment period prior to review of such an application, but the comment period for this particular application was extended to 60 days due to increased public interest.
The controversy over the permit request centers around whether these whales are truly being kept for educational purposes, and whether they are being imported in what the Marine Mammal Protection Act defines as a humane manner - or, in the words of the statute, a "method of taking which involves the least possible degree of pain and suffering practicable to the mammal involved."
Naomi Rose, a senior scientist with The Humane Society of the United States, questioned whether the belugas would be transported in a humane manner. Although aquarium officials said that they believed stress associated with capture and transport is short-lived, Rose said her organization disagrees.
"The most likely cause (of death in captive belugas), in my opinion, is chronic stress," she said, citing research conducted at Mystic Aquarium linking transportation and high levels of stress in beluga whales.
The Georgia Aquarium's chief veterinarian, Greg Bossart, sought to emphasize his enterprise's concern for the belugas' welfare and described its medical facilities as one of the largest and most modern aquarium hospitals in the world. Georgia Aquarium's Correll Center includes a surgery suite and a pathology room, along with water quality and diagnostic labs. Bossart also said that the belugas received regular, comprehensive medical exams as well as daily exams from their trainers.
Other objections to the permit request came from scientists and activists who do not consider the exhibits at Georgia Aquarium and SeaWorld parks "educational." Lori Marino, a neuroscientist who studies dolphin and whale intelligence at the Kimmela Center for Animal Advocacy, contended that no one was actually being educated at these locations.
"Theme parks publish material that is often false and misleading on dolphin and whale intelligence," she charged, adding that she believes these organizations downplay the animals' intelligence to rationalize keeping them in captivity.
Marino also described a course at Georgia Aquarium that was marketed as an "animal behavior" class, but which she regarded as a course in "animal husbandry."
But no shortage of educators lined up to defend the Georgia Aquarium, as school principals, teachers, and university professors from the Atlanta region praised the aquarium's beluga exhibit. They were enthusiastic about the hands-on nature of the aquarium, saying that students learned more by actually observing the animals rather than by listening to a lecture.
"With the aquarium, we can make every teacher's words come to life," declared Brian Davis, vice president of education and training at the Georgia Aquarium.

jueves, 18 de octubre de 2012

Misterio en Florida por un globo ocular gigante

Del tamaño de una bola de softbol, los especialistas están a la espera de los análisis genéticos para determinar a qué especie marina pertenece el gran ojo azul



El hallazgo del globo ocular gigante en una playa del sur de Florida ha causado alboroto en internet y en la comunidad de estudio de la biología marina.

El enorme globo ocular azul podría ser el de un calamar de aguas profundas o de un pez espada grande, dijo Heather Bracken-Grissom, profesora asistente en el Programa de Ciencia Marina de la Universidad Internacional de Florida en Miami.
 
Un hombre encontró el gran ojo cuando paseaba por la mañana en Pompano Beach justo al norte de Fort Lauderdale. Se puso en contacto con funcionarios estatales de vida silvestre, quienes tomaron posesión del globo ocular del tamaño de una bola de softbol.

Bracken-Grissom comentó que tan pronto como llegaron las fotografías el jueves a internet, comenzó a conversar con sus colegas. "Cada vez que algo extraño y demencial es arrastrado a la playa, resulta definitivamente interesante", agregó.




La profesora y sus colegas llegaron a la conclusión de que el cristalino y pupila del globo ocular son similares en forma a los del calamar de aguas profundas. Señaló que el globo ocular de esta especie puede ser tan grande como un balón de softbol y puede dislocarse fácilmente.

El misterio probablemente no se resolverá sino hasta que se terminen los análisis en el Instituto de Investigación de Vida Silvestre y pesca de Florida en St. Petersburg. "Va a ser muy interesante ver qué muestra el análisis genético", dijo Bracken-Grissom.

Añadió que la noticia sobre el globo ocular gigante viajó rápidamente; incluso familiares de California le llamaron por teléfono para preguntarle su opinión. "Algo como esto emociona mucho al público en relación con el misterioso reino del océano", señaló.