Text by University of Miami Rosenstiel School of Marine & Atmospheric Science, Photo by NOAA



El Nino, the periodic eastern Pacific phenomenon credited with shielding the United States and Caribbean from severe hurricane seasons, may be overshadowed by its brother in the central Pacific due to global warming, according to an article in the September 24 issue of the journal Nature.

"There are two El Ninos, or flavors of El Nino," said Ben Kirtman, co-author of the study and professor of meteorology and physical oceanography at the University of Miami's Rosentstiel School of Marine and Atmospheric Science. "In addition to the eastern Pacific El Nino which we know and love, a second El Nino in the central Pacific is on the increase."

El Nino is a recurring warm water current along the equator in the Pacific Ocean that affects weather circulation patterns in the tropics. The eastern El Nino increases wind sheer in the Atlantic that may hamper the development of major hurricanes there. The central Pacific El Nino, near the International Dateline, has been blamed for worsening drought conditions in Australia and India as well as minimizing the effects of its beneficial brother to the east.

Led by Sang-Wook Yeh of the Korea Ocean Research & Development Institute, a team of scientists applied Pacific Ocean sea surface temperature data from the past 150 years to 11 global warming models developed by the Intergovernmental Panel on Climate Change. Eight of the models showed that global warming conditions will increase the incidence of the central Pacific El Nino. Over the past 20 years, according to the data, the frequency of an El Nino event in the central Pacific has increased from one out of every five to half of all El Nino occurrences.

"The results described in this paper indicate that the global impacts of El Nino may significantly change as the climate warms," said Yeh.

Though the centers of the central and eastern areas are roughly 4,100 miles apart, El Ninos historically have not simultaneously occurred in both places. An increase in central Pacific El Nino events may reduce the hurricane-shielding effects of the eastern Pacific event.

"Currently, we are in the middle of a developing eastern Pacific El Nino event," said Kirtman, "which is part of why we're experiencing such a mild hurricane season in the Atlantic. We also anticipate the southern United States to have a fairly wet winter, and the northeast may be dry and warm."

Kirtman expects the current El Nino event to end next spring, perhaps followed by a La Nina, which he expects may bode for a more intense Atlantic hurricane season in 2010.

Growing up in southern California, Kirtman frequently had to man the sump pump in his family's basement during the rainy season, which he learned later was caused by El Nino.

"We're finally learning about how ocean current flows and increases in sea surface temperature influence weather patterns, which affect every one of us, including the kid manning the sump pump," he said. "I have devoted much of my career to studying El Nino because of how it affects people and their lives."

Kirtman works with various meteorological organizations around the world to help developing countries respond to climate extremes.

"We provide them with the forecasts," he said, "and the countries use the results to develop their response."

Text by California Academy of Sciences, Photo by MBARI



New species are not just discovered in exotic locales--even places as urban as California still yield discoveries of new plants and animals. Academy scientists recently named a new species of chimaera, an ancient and bizarre group of fishes distantly related to sharks, from the coast of Southern California and Baja California, Mexico.

The new species, the Eastern Pacific black ghostshark (Hydrolagus melanophasma), was described in the September issue of the international journal Zootaxa by a research team including Academy Research Associates David Ebert and Douglas J. Long. Additional co-authors included Kelsey James, a graduate student at Moss Landing Marine Laboratories, and Dominique Didier from Millersville University in Pennsylvania. This is the first new species of cartilaginous fish to be described from California waters since 1947.

Chimaeras, also called ratfish, rabbitfish, and ghostsharks, are perhaps the oldest and most enigmatic groups of fishes alive today. Their closest living relatives are sharks, but their evolutionary lineage branched off from sharks nearly 400 million years ago, and they have remained an isolated group ever since. Like sharks, chimaeras have skeletons composed of cartilage and the males have claspers for internal fertilization of females.

Unlike sharks, male chimaeras also have retractable sexual appendages on the forehead and in front of the pelvic fins and a single pair of gills. Most species also have a mildly venomous spine in front of the dorsal fin. Chimaeras were once a very diverse and abundant group, as illustrated by their global presence in the fossil record. They survived through the age of dinosaurs mostly unchanged, but today these fishes are relatively scarce and are usually confined to deep ocean waters, where they have largely avoided the reach of explorers and remained poorly known to science.

This new species belongs to the genus Hydrolagus, Latin for 'water rabbit' because of its grinding tooth plates reminiscent of a rabbit's incisor teeth. This new species was originally collected as early as the mid 1960s, but went unnamed until this year because its taxonomic relationships were unclear. A large blackish-purple form, Hydrolagus melanophasma (melanophasma is Latin for 'black ghost'), is found in deep water from the coast of Southern California, along the western coast of Baja California, and into the Sea of Cortez (Gulf of California). This species is known from a total of nine preserved museum specimens, and from video footage taken of it alive by a deep-water submersible in the Sea of Cortez.

Renewed exploration of the world's deep oceans and more extensive taxonomic analysis of chimaera specimens in museum collections have led to a boom in the number of new chimaera species discovered worldwide in the last decade, including two species from the Gal pagos Islands named by Didier, Ebert, and Long in 2006 that were originally collected by Academy scientist John McCosker. With further advances in research and discovery, perhaps more will be known about these living fossils and their diversity in the world's oceans.

Text and Photo by Harvard University



A new analysis of extinct sea creatures suggests that the transition from egg-laying to live-born young opened up evolutionary pathways that allowed these ancient species to adapt to and thrive in open oceans.

The evolutionary sleuthing is described this week in the journal Nature by scientists at Harvard University and the University of Reading who also report that the evolution of live-born young depended crucially on the advent of genes -- rather than incubation temperature -- as the primary determinant of offspring sex.

Having drawn this link in three lineages of extinct marine reptiles -- mosasaurs, sauropterygians, and ichthyosaurs -- the scientists say that genetic, or chromosomal, sex determination may have played a surprisingly strong role in adaptive radiations and the colonization of the world's oceans by a diverse array of species.

"Determining sex with genetic mechanisms allowed marine reptiles to give live birth, in the water, as opposed to laying eggs on a nesting beach," says Chris Organ, a research fellow in Harvard's Department of Organismic and Evolutionary Biology. "This freed these species from the need to move and nest on land. As a consequence extreme physical adaptations evolved in each group, such as the fluked tails, dorsal fins, and the wing-like limbs of ichthyosaurs."

Mosasaurs, sauropterygians, and ichthyosaurs invaded the Mesozoic seas between 251 million and 100 million years ago. All three groups of extinct marine reptiles breathed air, but evolved other adaptations to life in the open ocean, such as fin-shaped limbs, streamlined bodies, and changes in bone structure. Some evolved into enormous predators, such as porpoise-like ichthyosaurs that grew to more than 20 meters in length. Ichthyosaurs, and possibly mosasaurs, even evolved tail-first birth, an adaptation that helps modern whales and porpoises avoid drowning during birth.

"Losing the requirement of dry land during the life cycle of ichthyosaurs and other marine reptiles freed them to lead a completely aquatic existence, a shift that seems advantageous in light of the diversification that followed," says Daniel E. Janes, a research associate in Harvard's Department of Organismic and Evolutionary Biology.

Even though populations of most animals have males and females, the way sex is determined in offspring varies. Some animals rely primarily on sex chromosomes, as in humans where two X chromosomes make a female and an X and a Y chromosome make a male. Among living marine species, whales, porpoises, manatees, and sea snakes have chromosomal sex determination.

In sea turtles and saltwater crocodiles, on the other hand, the sex of offspring is generally determined by the temperature at which eggs incubate. These species are also bound to a semi-terrestrial existence because their gas-exchanging hard-shelled eggs must be deposited on land.

"No one has clearly understood how sex determination has co-evolved with live birth and egg laying," Organ says.

Organ, Janes, and colleagues show that evolution of live birth in a species depends on the prior evolution of genetic sex determination. Since the fossilized remains of pregnant mosasaurs, sauropterygians, and ichthyosaurs show that these species gave birth to live young, they must also have employed genetic sex determination, a point on which the fossil record is silent.

Organ and Janes' co-authors on the Nature paper are Andrew Meade and Mark Pagel of the University of Reading. Their work was funded by Harvard's Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology and by the National Institutes of Health.

Text and Photo by University at Buffalo



J. David Smith, Ph.D., a comparative psychologist at the University at Buffalo who has conducted extensive studies in animal cognition, says there is growing evidence that animals share functional parallels with human conscious metacognition -- that is, they may share humans' ability to reflect upon, monitor or regulate their states of mind.

Smith makes this conclusion in an article published the September issue of the journal Trends in Cognitive Science (Volume 13, Issue 9). He reviews this new and rapidly developing area of comparative inquiry, describing its milestones and its prospects for continued progress.

He says "comparative psychologists have studied the question of whether or not non-human animals have knowledge of their own cognitive states by testing a dolphin, pigeons, rats, monkeys and apes using perception, memory and food-concealment paradigms.

"The field offers growing evidence that some animals have functional parallels to humans' consciousness and to humans' cognitive self-awareness," he says. Among these species are dolphins and macaque monkeys (an Old World monkey species).

Smith recounts the original animal-metacognition experiment with Natua the dolphin. "When uncertain, the dolphin clearly hesitated and wavered between his two possible responses," he says, "but when certain, he swam toward his chosen response so fast that his bow wave would soak the researchers' electronic switches.

"In sharp contrast," he says, "pigeons in several studies have so far not expressed any capacity for metacognition. In addition, several converging studies now show that capuchin monkeys barely express a capacity for metacognition.

"This last result," Smith says, "raises important questions about the emergence of reflective or extended mind in the primate order.

"This research area opens a new window on reflective mind in animals, illuminating its phylogenetic emergence and allowing researchers to trace the antecedents of human consciousness."

Smith, a professor in the UB Department of Psychology and Center for Cognitive Sciences, is recognized for his research and publications in the field of animal cognition.

He and his colleagues pioneered the study of metacognition in nonhuman animals, and they have contributed some of the principal results in this area, including many results that involve the participation of Old World and New World monkeys who have been trained to use joysticks to participate in computer tasks.

Their research is supported by the National Institute of Child Health and Development and the National Science Foundation.

Smith explains that metacognition is a sophisticated human capacity linked to hierarchical structure in the mind (because the metacognitive executive control processes oversee lower-level cognition), to self-awareness (because uncertainty and doubt feel so personal and subjective) and to declarative consciousness (because humans are conscious of their states of knowing and can declare them to others).

Therefore, Smith says, "it is a crucial goal of comparative psychology to establish firmly whether animals share humans' metacognitive capacity. If they do, it could bear on their consciousness and self-awareness, too."

In fact, he concludes, "Metacognition rivals language and tool use in its potential to establish important continuities or discontinuities between human and animal minds."

Text by Georgia Institute of Technology, Photo by NOAA



Tornadoes that occur from hurricanes moving inland from the Gulf Coast are increasing in frequency, according to researchers at the Georgia Institute of Technology. This increase seems to reflect the increase in size and frequency among large hurricanes that make landfall from the Gulf of Mexico.

The findings can be found in Geophysical Research Letters online and in print in the September 3, 2009 issue.

"As the size of landfalling hurricanes from the Gulf of Mexico increases, we're seeing more tornadoes than we did in the past that can occur up to two days and several hundred miles inland from the landfall location," said James Belanger, doctoral student in the School of Earth and Atmospheric Sciences at Georgia Tech and lead author of the paper.

Currently, it's well known that when hurricanes hit land, there's a risk that tornadoes may form in the area. Until now, no one has quantified that risk because observations of tornadoes were too sporadic prior to the installation of the NEXRAD Doppler Radar Network in 1995. Belanger along with co-authors Judith Curry, professor and chair of the School of Earth and Atmospheric Sciences at Tech and research scientist Carlos Hoyos, decided to see if they could create a model using the more reliable tornado record that's existed since 1995.

The model that they developed for hurricane-induced tornadoes uses four factors that serve as good predictors of tornado activity: size, intensity, track direction and whether there's a strong gradient of moisture at midlevels in the storm's environment.

"The size of a tropical cyclone basically sets the domain over which tornadoes can form. So a larger storm that has more exposure over land has a higher propensity for producing tornadoes than a smaller one, on average," said Belanger.

The team looked at 127 tropical cyclones from 1948 up to the 2008 hurricane season and went further back to 1920 modifying their model to account for the type of data collected at that time. They found that since 1995 there has been a 35 percent percent increase in the size of tropical cyclones from the Gulf compared to the previous active period of storms from 1948-1964, which has lead to a doubling in the number of tornadoes produced per storm. The number of hurricane-induced tornadoes during the 2004 and 2005 hurricane seasons is unprecedented in the historical record since 1920, according to the model.

"The beauty of the model is that not only can we use it to reconstruct the observational record, but we can also use it as a forecasting tool," said Belanger.

To test how well it predicted the number of tornadoes associated with a given hurricane, they input the intensity of the storm at landfall, it's size, track and moisture at mid-levels, and were able to generate a forecast of how many tornadoes formed from the hurricane. They found that for Hurricane Ike in 2008, their model predicted exactly the number of tornadoes that occurred, 33. For Hurricane Katrina in 2005, the model predicted 56 tornadoes, and 58 were observed.

The team's next steps are to take a look to see how hurricane size, not just intensity (as indicated by the Safir-Simpson scale), affects the damage experienced by residents.

"Storm surge, rain and flooding are all connected to the size of the storm," said Curry. "Yet, size is an underappreciated factor associated with damage from hurricanes. So its important to develop a better understanding of what controls hurricane size and how size influences hurricane damage. The great damage in Galveston from Hurricane Ike in 2008 was inconsistent with Category 2 wind speeds at landfall, but it was the large size that caused the big storm surge that did most of the damage."

Text and Photo by NASA


Patterns of average winter ice thickness from February to March show thicker ice in 1988 (left), compared to thinner ice averaged from 2003-2008 (right).

This summer, a group of scientists and students -- as well as a Canadian senator, a writer, and a filmmaker -- set out from Resolute Bay, Canada, on the icebreaker Louis S. St-Laurent. They were headed through the Northwest Passage, but instead of opening shipping lanes in the ice, they had gathered to open up new lines of thinking on Arctic science.

Among the participants in the shipboard workshop (hosted by Fisheries and Oceans Canada) was Ron Kwok of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Kwok has long provided checkups on the health of Arctic sea ice -- the frozen sea water floating within the Arctic Ocean basin. He also knows that some important clues about ice changes can't be seen from a ship.

Extending the Record

While satellites provide accurate and expansive coverage of ice in the Arctic Ocean, the records are relatively new. Satellites have only monitored sea ice extent since 1973. NASA's Ice, Cloud, and land Elevation Satellite (ICESat) has been on the task since 2003, allowing researchers to estimate ice thickness as well.

To extend the record, Kwok and Drew Rothrock of the University of Washington, Seattle, recently combined the high spatial coverage from satellites with a longer record from Cold War submarines to piece together a history of ice thickness that spans close to 50 years.

Analysis of the new record shows that since a peak in 1980, sea ice thickness has declined 53 percent. "It's an astonishing number," Kwok said. The study, published online August 6 in Geophysical Research Letters, shows that the current thinning of Arctic sea ice has actually been going on for quite some time.

"A fantastic change is happening on Earth -- it's truly one of the biggest changes in environmental conditions on Earth since the end of the ice age," said Tom Wagner, cryosphere program manager at NASA Headquarters. "It's not an easy thing to observe, let alone predict, what might happen next."

Sea ice influences the Arctic's local weather, climate, and ecosystems. It also affects global climate. As sea ice melts, there is less white surface area to reflect sunlight into space. Sunlight is instead absorbed by the ocean and land, raising the overall temperature and fueling further melting. Ice loss puts a damper on the Arctic air conditioner, disrupting global atmospheric and ocean circulation.

To better identify what these changes mean for the future, scientists need a long-term look at past ice behavior. Each year, Arctic ice undergoes changes brought about by the seasons, melting in the summer warmth and refreezing in the cold, dark winter. A single extreme melt or freeze season may be the result of any number of seasonal factors, from storminess to the Arctic Oscillation (variations in atmospheric circulation over the polar regions that occur on time scales from weeks to decades).

But climate is not the same as weather. Climate fluctuates subtly over decades and centuries, while weather changes from day to day and by greater extremes.

"We need to understand the long-term trends, rather than the short-term trends that could be easily biased by short-term changes," Kwok said. "Long-term trends are more reliable indicators of how sea ice is changing with the global and regional climate."

That's why a long-term series of data was necessary. "Even decadal changes can be cyclical, but this decline for more than three decades does not appear to be cyclical," Rothrock said.

All the Ice Counts

Arctic sea ice records have become increasingly comprehensive since the latter half of the 20th century, with records of sea ice anomalies viewed from satellites, ships, and ice charts collected by various countries. Most of that record, kept in the United States by the National Snow and Ice Data Center at the University of Colorado, Boulder, describes the areal extent of sea ice.

But a complete picture of sea ice requires an additional, vertical measurement: thickness. Melting affects more than just ice area; it can also impact ice above and below the waterline. By combining thickness and extent measurements, scientists can better understand how the Arctic ice cover is changing.

Kwok and other researchers used ICESat's Geoscience Laser Altimeter System to estimate the height of sea ice above the ocean surface. Knowing the height, scientists can estimate how much ice is below the surface.

Buoyancy causes a fraction (about 10 percent) of sea ice to stick out above the sea surface. By knowing the density of the ice and applying "Archimedes' Principle" -- an object immersed in a fluid is buoyed by a force equal to the weight of the fluid displaced by the object -- and accounting for the accumulation of snowfall, the total thickness of the ice can be calculated.

In 2008, Kwok and colleagues used ICESat to produce an ice thickness map over the entire Arctic basin. Then in July 2009, Kwok and colleagues reported that multiyear 'permanent' ice in the Arctic Ocean has thinned by more than 40 percent since 2004. For the first time, thin seasonal ice has overtaken thick older ice as the dominant type.

Submarines and Satellites

To put the recent decline in context, Kwok and Rothrock examined the recent five-year record from ICESat in the context of the longer history of ice thickness observed by U.S. Navy submarines.

During the Cold War, the submarines collected upward-looking sonar profiles, for navigation and defense, and converted the information into an estimate of ice thickness. Scientists also gathered profiles during a five-year collaboration between the Navy and academic researchers called the Scientific Ice Expeditions, or "SCICEX," of which Rothrock was a participant. In total, declassified submarine data span nearly five decades--from 1958 to 2000--and cover a study area of more than 1 million square miles, or close to 40 percent of the Arctic Ocean.

Kwok and Rothrock compared the submarine data with the newer ICESat data from the same study area and spanning 2003 to 2007. The combined record shows that ice thickness in winter of 1980 averaged 3.64 meters. By the end of 2007, the average was 1.89 meters.

"The dramatic decrease in multiyear ice coverage is quite remarkable and explains to a large degree the decrease in total ice area and volume," Kwok said.

Rothrock, who has worked extensively with the submarine data, agrees. "This paper shows one of the most compelling signals of global warming with one of the greatest and fastest regional environmental impacts."

Ice Through Human Eyes

While it is critical to keep monitoring the Arctic with satellites and aircraft, Kwok believes there is also a benefit in physically standing in a place and seeing the changes through human eyes--particularly for non-scientists, who do not keep a close watch on sea ice.

The August 2009 workshop in the Northwest Passage brought together an eclectic group of politicians, artists, and scientists to see the ice firsthand. The challenge was to see the problem of a changing Arctic environment from a variety of scientific, political, cultural and human perspectives and to discuss the future of collaborative study in the Arctic. The science of sea ice has implications for people's livelihoods, for long-established ecosystems, and for opening a new part of the world to exploration and exploitation.

The workshop participants now take their experiences and observations back to warmer climates, where there is sometimes less urgency about ice retreat.

"Sea ice is about more than just hard science; it's a geopolitical and human issue," Kwok noted. "There is a big personal impact when you get away from your desk and see it in person."

Text and Photo by NOAA



Persistent winds and a weakened current in the Mid-Atlantic contributed to higher than normal sea levels along the Eastern Seaboard in June and July, according to a new NOAA technical report.

After observing water levels six inches to two feet higher than originally predicted, NOAA scientists began analyzing data from select tide stations and buoys from Maine to Florida and found that a weakening of the Florida Current Transport--an oceanic current that feeds into the Gulf Stream--in addition to steady and persistent Northeast winds, contributed to this anomaly.

"The ocean is dynamic and it's not uncommon to have anomalies," said Mike Szabados, director of NOAA's Center for Operational Oceanographic Products and Services. "What made this event unique was its breadth, intensity and duration."

The highest atypical sea levels occurred closer to where the anomaly formed in the Mid-Atlantic, where cities like Baltimore, Md., at times experienced extreme high tides as much as two feet higher than normal. Data from NOAA's National Water Level Observation Network tide stations, Atlantic Oceanographic and Meteorological Laboratory, and National Data Buoy Center, are published in the report.

Impacts of the event were amplified by the occurrence of a perigean-spring tide, the natural timing of the season and month when the moon is closest to the Earth and its gravitational pull heightens the elevation of the water. The combined effects of this tide with the sea level anomaly produced minor flooding on the coast.

"The report is a good first assessment," said NOAA Oceanographer William Sweet, Ph.D. "However, NOAA, with our academic partners, should continue to investigate the broader causes behind the event. Further analysis is needed to fully understand what is driving the patterns we observed."

Text by Geesthacht GKSS Research Centre Photo by NASA
Scientists of the Geesthacht GKSS Research Centre have developed a radar system with which it is possible to study the behavior of sea waves. This technology will be used immediately on the North Sea on the FINO3 research platform in order to determine the interactions between offshore wind power machines and swells.

The location of the FINO3 research platforms, the "Dan Tysk" sand bank, is located approximately 80 kilometres to the west of Sylt where up to 80 wind power plants will be located in just a few years. FINO3 is used by researchers to estimate the environmental consequences and technical risks of offshore wind energy parks. Changes in the sea swell are also of great interest in addition to the observations of bird migration or the measurement of lightening frequencies on the sea.

To determine how much of an effect large waves and what is known as 'breakers' have on wind power plants and to what extent the structures can change the surrounding swell, the coastal researchers of the Geesthacht GKSS Research Centre installed a Doppler radar approximately 50 metres above sea level on the FINO3 lattice mast.

"With our radar, we can even track the individual waves for the first time", writes Dr. Freidwart Ziemer, GKSS Department Manager of Radar Hydrology, the unique part of the project. For several years, Ziemer and his team have studied the swell and the behaviour of large breakers. The information is transmitted by FINO3 to Geesthacht via satellite.

Assessing swells better

The frequency of large breakers and the force which creates the steep giant waves are of particular interest not only to researchers but also the designers and operators of offshore wind power plants or oil platforms.

Each individual wind rotor creates turbulent air flows in its "tow" and periodical movements, which can have an effect on other structures. This can result in undesired or even dangerous vibrations. If there is an interaction between the waves and the individual wind power plants, this can result in interferences. This means in a wave field which is harmless without a windmill park, single, very high waves can be created by these interferences which could possibly have a critical effect on these plants.

"I am sure that we will soon be able to better assess the swells and the force of the breakers," says Friedwart Ziemer. This means that the breaker behaviour could be taken into account better in planning and the stability of the systems can be more predictable.

Solid position on the COSYNA North Sea monitoring system

The FINO3 research platform will be an important component in the new COSYNA measurement network initiated by GKSS. A comprehensive monitoring system will be created in the German North Sea area to record, predict and provide scientific analysis of the current state and development of the coastal waters with the major COSYNA project (Coastal Observation System for Northern and Arctic Seas).

FINO3 will provide the Geesthacht coast researchers information on seafaring and the wind. Breaker statistics are also planned. The Doppler radar technology was developed by the GKSS employees in unison with the Technical University of Saint Petersburg. The initial test readings with the new wave radar from the shore have already been carried out successfully.

The project coordinator of FINO3 is the research and development centre of the Kiel University of Applied Sciences (Fachhochschule Kiel GmbH). The project executing organisation is the Federal ministry of the environment, natural protection and reactor safety (BMU).

Text by UCSB, Photo by Rod Rolle



The green mussel is known for being a notoriously invasive fouling species, but scientists have just discovered that it also has a very powerful form of adhesion in its foot, according to a recent article in the Journal of Biological Chemistry. The stickiness of the mussel's foot could possibly be copied to form new man-made adhesives.

Other mussels have inspired synthetic polymers that have been made into versatile adhesives and coatings, explained J. Herbert Waite, senior author and a professor in UC Santa Barbara's Marine Science Institute. They all rely on proteins that contain an amino acid called "Dopa," (identical to the Dopa used to treat Parkinson's disease) and have been studied extensively by Waite and his research group.

Waite learned that the green mussel, Perna viridis, relies on an alternative to the common "Dopa" chemistry, based on an elaborate modification of the amino acid tryptophan in the green mussel's adhesive protein. Its adhesive chemistry is much more complicated than that of mussels previously studied. It took Waite and his team six years to unravel the story.

The green mussel's sticky adhesiveness has the potential to help form strong bonds in wet surfaces, including teeth and bones. In addition, the adhesive could be used to repair ships that have developed cracks while at sea and must be repaired in a wet environment.

Waite was first alerted to the complicated adhesive of the green mussel when a Japanese group contacted him to comment on their research on the animal. He then learned of an infestation of green mussels in Tampa Bay, Fla.

On further study, he learned that the aggressive green mussel had moved from India's Sea of Bengal to many locations around the world, including the coasts of Japan, Australia, Korea, China, the Philippines, and Indonesia. Additionally, many Pacific Islands and the coasts of some countries surrounding the Gulf of Mexico have been invaded. "People are interested in how they invade, adapt, and spread so easily," said Waite.

Waite asked the U.S. Geological Survey and Florida Sea Grant to send him frozen specimens from Tampa Bay, as this is the only way that California would allow the green mussel to be shipped into the state. The feet were severed from about 100 freshly shucked mussels. After thawing, they were placed in a tissue grinder and then centrifuged for study.

"One aspect that is kind of scary is that the green mussel is more successful than other kinds of mussels at living in polluted water," said Waite. Coastal power plants that flush warm seawater into the ocean provide an ideal environment for the mussels. "Once they get a foothold, they stay."

The other authors on the paper are Hua Zhao and Jason Sagert of the Institute of Chemical and Engineering Sciences in Singapore, and Dong Soo Hwang of the Marine Science Institute at UCSB.

Text and Photo by Stony Brook University




A long-term field and DNA study by the Institute for Ocean Conservation Science at Stony Brook University, University of Miami, Field Museum of Chicago and others has shown that young lemon sharks born at the Bimini islands, Bahamas, tend to stay near their coastal birthplace for many years. While shark research and conservation typically focuses on baby sharks confined to shallow habitats, or ocean-roaming adults, less is known about these intermediate-aged animals, which are the breeders of tomorrow and are roughly similar in development to human 'tweens' and teenagers. Tropical island-nations that sacrifice their nursery habitats to coastal development are therefore likely to lose not only babies but also much older sharks from their local areas, with potentially dire effects on the surrounding ecosystem. The study, conducted over a 14-year period at the Bimini Biological Field Station, is the cover article in the August issue of Molecular Ecology, a leading international scientific journal.

"It takes some sharks more than a decade to reach reproductive age, so we set out to better understand the phase of their development from when they are a couple of years old until they are on the verge of sexual maturity," said lead author Dr. Demian Chapman, shark scientist with the Institute for Ocean Conservation Science at Stony Brook University (SBU) in New York, and an assistant professor at SBU. "We were very surprised to see that many lemon sharks lingered for years around the island where they were born -- often more than half of their development to adulthood."

Fear of deep water--and the bigger predators that live there-- combined with abundant prey in the mangroves around Bimini probably keeps these island-born sharks in safer waters near home for several years after their birth. "This means that using marine reserves and other local conservation measures may help protect sharks born around tropical islands for much longer than we thought," Dr. Chapman explained. He suspects that future research could show that these stay-at-home behavior patterns are common among many shark species that live and breed around tropical islands. "If island communities develop all of their shark nursery habitats, like mangroves, or overfish baby sharks in local waters, then they will subsequently lose a big chunk of the older sharks as well," he said.

Love them or not, sharks are essential to healthy oceans. Removing these top-level ocean predators will disrupt the local food web and cause negative consequences for other species and the ecosystem at large. Moreover, many tropical islands generate substantial revenue from shark-dive tourism, which this new research suggests will be heavily reliant on sharks born in local nursery areas.

During the course of the Bimini study, from 1995 to 2007, over 1,700 immature lemon sharks were caught, tagged and released. The implanted tags, plus subsequent recaptures and DNA analysis, showed that more than half of the 3- to 7-year-old sharks caught off Bimini were born locally and had lingered near their birthplace for years. Full results are described in the study, entitled, Long-term natal site-fidelity by immature lemon sharks (Negaprion brevirostris) at a subtropical island.

"In general, the survival of these intermediate-aged sharks is critical for sustaining shark populations," said study co-author Dr. Samuel Gruber, Professor at the University of Miami's Rosenstiel School of Marine and Atmospheric Science and Director of the Bimini Biological Field Station, who has been leading the overall lemon shark research program at Bimini since 1978. "Our study suggests that local conservation efforts can help many lemon sharks born at islands like Bimini survive through roughly half of their development to adulthood. Broader scale, sometimes international, management is needed to protect them after they've left their birthplace as adolescents and adults."

Detailed information on how sharks disperse from their birthplace could be very useful for conservation efforts throughout the tropics, given that many tropical shark species are threatened by over exploitation to supply the trade for shark fin soup, for which demand is especially high in Asia. Between 22 and 73 million sharks are killed each year to supply the fin trade, and international management agencies are scrambling for solutions to stem severe shark population declines.

"Our study suggests that many tropical island nations may not have to wait for complex international shark regulations to be established in order to act," said Dr. Chapman. "Their local management efforts could give immature sharks a chance to grow up in relative safety until they are big and 'bad' enough to roam deeper habitats far from home, where broader scale protection becomes more important."

The research team is now extending its study to answer one of the great mysteries of shark biology: do sharks home back to their birthplace as adults? Co-author Dr. Kevin Feldheim of the Field Museum in Chicago, who led the genetics part of the study, said: "This research showed that most of the young sharks left the island by the time they were mature. Now we want to find out if they end up coming back to the place where they were born to breed, much like salmon and sea turtles do."