The smell of sea salt in the air is a romanticized feature of life along a seacoast. Wind and waves kick up spray, and bits of sodium chloride -- common table salt -- can permeate the air.

It is believed that as much as 10 billion metric tons of chloride enters the air mass through this process each year, but just a tiny fraction -- perhaps one-third of 1 percent -- does anything but fall back to the surface.

The bit of chloride lingering in the air can react with nitrogen oxides, formed when fuel is burned at high temperature, to form nitryl chloride, a forerunner of chlorine atoms, the most reactive form of chlorine. Those atoms can contribute to smog formation in coastal areas.

Now, in a surprise, researchers have found that this chemistry thought to be restricted to sea spray occurs at similar rates in air above Boulder, Colo., nearly 900 miles away from any ocean. What's more, local air quality measurements taken in a number of national parks across the United States imply similar conditions in or near other non-coastal metropolitan areas.

"It's there. We know it's there. But we don't have a good handle on where that chloride comes from," said Joel Thornton, a University of Washington associate professor of atmospheric sciences and lead author of a paper documenting the findings, published March 11 in Nature.

After sea spray, the largest global source of chlorides is coal burning, with biomass burning not far behind. Thornton said potential sources of chloride in the Boulder-Denver area include smoke from fireplaces, chemicals used on icy winter roads or even air drifting in from giant salt flats in Nevada and Utah, but there currently is no sure way to know the source.

In February 2007, a team including Thornton prepared to set out from Boulder for a research cruise from Long Island Sound to Iceland via Norway. The plan was to sample nitryl chloride levels in marine air, which computer models predicted would not exceed 50 parts per trillion.

Before leaving, the scientists decided to test the equipment they would use to detect airborne nitryl chloride on the cruise by sampling the air in Boulder, a mile above sea level.

"That night when we just nonchalantly stuck our tube out the window, we were getting readings of 500 parts per trillion in Boulder," Thornton recalled. Those levels turned out to be comparable to what the scientists later recorded on the research cruise, indicating the computer models greatly underestimate nitryl chloride in the air near the Earth's surface.

The researchers returned to Boulder in 2009 to take more comprehensive measurements from a park 150 feet above the city, away from obvious chloride sources. They confirmed their earlier observations, and they gathered further confirmation from the national park air quality monitoring systems.

"We expect this to be occurring in other places as well," Thornton said.

The research focuses on a specific form of nitrogen oxides present only at night -- during the day it is broken down by even the faintest sunlight. It is commonly thought that much of the ozone- and haze-forming pollutants generated in metropolitan areas during a busy weekday are removed from the air during hours of darkness. The new research calls that into question, Thornton said.

The work suggests the nighttime form of nitrogen oxides reacts with haze particles containing chloride to form nitryl chloride, which in turn forms chlorine atoms and regenerate the smog-forming nitrogen oxides when the sun rises.

Chlorine atoms can reduce the lifetime of atmospheric mercury gas, as well as greenhouse gases such as methane. In polluted urban areas, they also enhance production of ozone, a key ingredient of smog that is potentially toxic to animal and plant life.

"Because of these impacts, we'd like to know what happens to these nitrogen oxides in nighttime air, where do they go, what do they do," Thornton said. He acknowledged that unraveling and understanding the ramifications of the findings will not be simple.

Text by University of Washington Photo by Phil Armitage/ UW

Scripps Institution of Oceanography, UC San Diego, paleoceanographer Richard Norris is one of 41 scientists presenting evidence that an asteroid impact really did kill off dinosaurs and myriad other organisms 30 years after the theory was first proposed.

The researchers are authors of a review paper being released Friday in the journal Science that represents a new salvo in an ongoing controversy over the cause of the mass extinction. Norris' contribution to the paper was evidence in seafloor sediment records that indicate how deep-sea life was profoundly reshaped by the impact.

"The story is a lot stronger now than 30 years ago, when it was admittedly a little more speculative," said Norris. "Since 1980, we have accumulated an overwhelming amount of evidence that there was an impact. We also think the evidence is overwhelming that there was a mass extinction as a direct result of this event."

In that year, father and son researchers Luis and Walter Alvarez first proposed the notion that an asteroid impact killed off the dinosaurs. They had discovered that high levels of iridium, an element rare on Earth but common on extraterrestrial objects like meteors, were uniformly present in sedimentary samples that could be dated back to the extinction event, which marked the transition between two geologic periods.

At the time, they did not know where on Earth that impact might have taken place. It would be another 11 years before researchers Alan Hildebrand and Glen Penfield suggested that a crater left behind by an asteroid impact was buried on the Yucatan peninsula. With the crater nearly 200 kilometers (125 miles) in diameter, the impact was one large enough to have caused the mass extinction in agreement with the Alvarez hypothesis.

The force of the impact itself - there is evidence of giant earthquakes and tsunami waves more than 1,000 feet tall being generated in the immediate aftermath - and the following profound atmospheric changes combined to make the planet uninhabitable for between 40 and 70 percent of all life forms on Earth.

But rival explanations, though outside the mainstream, have continued to proliferate in high-profile fashion. One theory that has gained widespread attention attributes the mass extinction to a volcanic event in India that took place at roughly the same time as the impact. Another faction of researchers acknowledges that the asteroid did strike but that its effects were not enough to cause the mass extinction.

Norris notes that an inspection of ancient layers of seafloor sediment around the world show a clear record of the event contained in a red or green band composed of materials ejected from the blast. These include pieces of rock like those on the Yucatan, glassy droplets that represent melted rock, microscopic diamonds made under the very high pressures produced by the impact and meteoric debris.

"There are also monster submarine landslides along the entire East Coast of the U.S. from the massive earthquake triggered by the impact," he said.

Norris points to several pieces of evidence from the deep sea that support a tight link between the impact and the mass extinction. In most places in the deep ocean, the impact debris layer is associated with an abrupt decrease in the size of fossils - the appearance of a dwarfed "disaster" fauna. Abrupt environmental changes throughout history such as the impact tend to favor smaller organisms that have more rapid lifecycles and fewer resource needs than larger organisms. Biological productivity plummets in many parts of the oceans immediately after the impact. The drop in productivity is partly reflected by a change in the color of deep-sea sediments - from creamy white to brown or grey - as light-colored fossil shells abruptly decreased in number.

Individually, the decrease in fossil size, the appearance of a "disaster fauna" and the plummet in ocean productivity are unusual, and together with an impact debris layer, are unique in the deep-sea sediment record.

"This is not a 'smoking gun,'" said Norris, "it's a 'smoking cannon.'"

Text and Photo by Scripps Institution of Oceanography

Reduce. Reuse. Recycle. We hear this mantra time and again. When it comes to carbon‹the "Most Wanted" element in terms of climate change‹nature has got reuse and recycle covered. However, it's up to us to reduce. Scientists at Harvard Medical School are trying to meet this challenge by learning more about the carbon cycle, that is, the process by which carbon moves from the atmosphere into plants, oceans, soils, the earth's crust, and back into the atmosphere again.

One of the biggest movers and shakers is the lowly cyanobacteria, an ocean-dwelling, one-celled organism. Pamela Silver, HMS professor of systems biology, and colleagues have uncovered details about how this bacteria fixes, or digests, carbon. These bacteria build miniature factories inside themselves that turn carbon into fuel.

Silver and her colleagues report that the bacteria organize these factories spatially, revealing a structural sophistication not often seen in single-celled organisms. This regular and predictable spacing improves the efficiency of carbon processing. In the future, an understanding of the mechanisms that govern this spatial organization may help improve the efficiency of designer bacteria engineered to produce carbon-neutral fuels such as biodiesel and hydrogen.

These findings will be published online March 5 in the journal Science.

The rod-shaped cyanobacteria are among the most abundant organisms on earth. Forty percent of the carbon in the carbon cycle is reused and recycled through these tiny creatures. To process carbon, cyanobacteria build soccer-ball-shaped structures inside themselves called carboxysomes. These tiny factories absorb carbon dioxide and convert it into sugar, which the bacteria then use to produce energy.

"The ocean is just packed with these bacteria. By studying them, we're understanding more about how the earth works," said Silver, who is also on the faculty of the Wyss Institute for Biologically Inspired Engineering at HMS. "I'm blown away by what's happening in the ocean and what we don't understand about it. There are a lot of things in the ocean that are going to be useful to us."

The research team, led by co-first authors, research fellows David Savage and Bruno Afonso, attached a fluorescent tag to proteins involved in building the carboxysome, then grew the tagged bacteria under a microscope.

The resulting images revealed that, instead of being randomly numbered and haphazardly placed, cyanobacteria build carboxysomes in numbers that scale with their size, and they space the factories evenly along their length. (see image, end of release)

The finding adds evidence for new ways to think about bacteria. "We had this idea of bacteria as a bag of enzymes, but that has been completely shattered," said Afonso. A single protein, called parA, acts as a kind of inner-bacterium stage manager, arranging the carboxysomes in a neat, single-file row, the researchers found. When they disabled the bacteria's ability to make the protein, the carboxysomes were distributed far more randomly.

The cyanobacteria lacking parA were also less "fit" for survival, said Savage. While wild-type bacteria cells have a consistent number of carboyxsomes, which in turn optimizes carbon processing and fitness, the knockout bacterium created daughter cells whose numbers of carboxysomes ranged from none to an excess. The daughter cells with few or no carboxysomes divide more slowly and also process fifty percent less carbon than daughter cells at the other end of the spectrum.

By tagging parA in wild-type bacteria, they discovered interesting dynamics in the protein. Thousands of parA proteins repeatedly cluster together and shoot quickly from one end of the bacterium to the other.

"It's amazing that you can generate this regularity and symmetry potentially from a single protein," said Savage. "It's amazing that it is somehow tuned by the dynamics of the protein." The researchers have not yet identified the exact mechanism parA uses to govern the spacing.

Many other bacteria also have the parA protein, which is known for separating chromosomes during cell division. "This work highlights how bacteria cobble together spare parts to achieve similar goals such as organization and segregation," said David Rudner, HMS assistant professor of microbiology and molecular genetics, who was not involved in the study.

These findings may help synthetic biologists one day create designer bacteria.

"Knowledge about how cells create and deploy specialized factories like the carboxysome opens the way to creating other kinds of mini factories that could perform useful functions," said Richard Losick, Harvard University professor of molecular and cellular biology, who was not involved in the study.

Silver's lab is looking into whether the carboxysome might be useful for optimizing the production of hydrogen by engineered bacteria. One challenge in designing hydrogen-producing bacteria is that the enzymes that produce hydrogen are sensitive to oxygen. The carboxysome may help solve this problem because its outer shell blocks out oxygen, protecting the enzymes inside from its toxic effects.

Text and Photo by Harvard Medical School

The massive magnitude 8.8 earthquake that struck the west coast of Chile last month moved the entire city of Concepcion at least 10 feet to the west, and shifted other parts of South America as far apart as the Falkland Islands and Fortaleza, Brazil.

These preliminary measurements, produced from data gathered by researchers from four universities and several agencies, including geophysicists on the ground in Chile, paint a much clearer picture of the power behind this temblor, believed to be the fifth-most-powerful since instruments have been available to measure seismic shifts.

Buenos Aires, the capital of Argentina and across the continent from the quake's epicenter, moved about 1 inch to the west. And Chile's capital, Santiago, moved about 11 inches to the west-southwest. The cities of Valparaiso and Mendoza, Argentina, northeast of Concepcion, also moved significantly.

The quake's epicenter was in a region of South America that's part of the so-called "ring of fire," an area of major seismic stresses which encircles the Pacific Ocean. All along this line, the tectonic plates on which the continents move press against each other at fault zones.

The February Chilean quake occurred where the Nazca tectonic plate was squeezed under, or "subducted," below the adjacent South American plate. Quakes routinely relieve pent-up geologic pressures in these convergence zones.

The research team deduced the cities' movement by comparing precise GPS (global positioning satellite) locations known prior to the major quake to those almost 10 days later. The US Geological Survey reported that there have been dozens of aftershocks, many exceeding magnitude 6.0 or greater, since the initial event February 27.

Mike Bevis, professor of earth sciences at Ohio State University, has led a project since 1993 that has been measuring crustal motion and deformation in the Central and Southern Andes. The effort, called the Central and Southern Andes GPS Project, or CAP, hopes to perhaps triple its current network of 25 GPS stations spread across the region.

"By reoccupying the existing GPS stations, CAP can determine the displacements, or 'jumps', that occurred during the earthquake," Bevis said. "By building new stations, the project can monitor the postseismic deformations that are expected to occur for many years, giving us new insights into the physics of the earthquake process."

Ben Brooks, an associate researcher with the School of Ocean and Earth Science and Technology at the University of Hawaii and co-principal investigator on the project, said that the event, tragic as it was, offers a unique opportunity to better understand the seismic processes that control earthquakes.

"The Maule earthquake will arguably become one of the, if not the most important great earthquake yet studied. We now have modern, precise instruments to evaluate this event, and because the site abuts a continent, we will be able to obtain dense spatial sampling of the changes it caused.

"As such the event represents an unprecedented opportunity for the earth science community if certain observations are made with quickly and comprehensively," Brooks said.

Working with Bevis and Brooks on the project are Bob Smalley, the University of Memphis, who is leading field operations in Argentina; Dana Caccamise at Ohio State, who is lead engineer, and Eric Kendrick, also from Ohio State, who is with Bevis now in Chile making measurements in the field.

Along with Ohio State University and the University of Hawaii, scientists from the University of Memphis and the California Institute of Technology are participating in the project. Additionally the Instituto Geografica Militar, the Universidad de Concepcion and the Centro de Estudios Cientificos, all in Chile, also were partners.

In Argentina. the Instituto Geografica Militar, the Universidad Nacional de Cuyo in Mendoza and the Unversidad Nacional de Buenos Aires are collaborating in the work. UNAVCO, a consortium of more than 50 institutions and agencies involved in research in the geosciences, is providing equipment for the project.

The researchers have constructed a map showing the relative movement of locations after the Maule, Chile earthquake.

Text and Photo by Ohio State University

Between the grains of sand on the sea floor there is an unknown and unexplored world. Pierre De Wit at Gothenburg University knows this well, and has found new animal species on the Great Barrier Reef, in New Caledonia, and in the sea off the Gullmarsfjord in the Swedish county of Bohuslän.

The layer of sand on ocean floor is home to a large part of the vast diversity of marine species. Species representing almost all classes of marine animals live here. The genus Grania, which belongs to the class of annelid worms Clitellata, is one of them.

Grania the globetrotter

Grania is a worm around two centimeters in length and mostly white, which is encountered in marine sand throughout the world, from the tidal zone to deep down in the ocean. The researcher Pierre De Wit, at the Department of Zoology of the University of Gothenburg, is analyzing exactly how many species of Grania there are and how they are related to other organisms.

Four new species

De Wit has conducted studies at the Great Barrier Reef in Australia, where he and his colleagues have found four entirely new species of the Grania worm. One of them is the beautifully green-colored Grania colorata. "These worms are usually colorless or white, and we have not been able to work out why this particular species is green," says De Wit.

Separate history

De Wit has also found a previously unknown worm in Scandinavia, dubbed Grania occulta, which can only be distinguished from a previously known species by DNA. The worms' genetics show that the evolutionary history of the two species is in fact entirely separate, and that one of them is actually more closely related to a species that looks completely different.

Important knowledge

"Species that were previously regarded as the same may prove to have a completely different function in the ecosystem, and have different tolerance of environmental toxins, for example. It is obviously important to know this in order to be able to take the right action to protect our fauna," says de Wit.

Text and Photo by University of Gothenburg

Life can be scary for endangered loggerhead sea turtles immediately after they hatch. After climbing out of their underground nest, the baby turtles must quickly traverse a variety of terrains for several hundred feet to reach the ocean.

While these turtles' limbs are adapted for a life at sea, their flippers enable excellent mobility over dune grass, rigid obstacles and sand of varying compaction and moisture content. A new field study conducted by researchers at the Georgia Institute of Technology is the first to show how these hatchlings use their limbs to move quickly on loose sand and hard ground to reach the ocean. This research may help engineers build robots that can travel across complex environments.

"Locomotion on sand is challenging because sand surfaces can flow during limb interaction and slipping can result, causing both instability and decreased locomotor performance, but these turtles are able to adapt," said Daniel Goldman, an assistant professor in the Georgia Tech School of Physics. "On hard-packed sand at the water's edge, these turtles push forward by digging a claw on their flipper into the ground so that they don't slip, and on loose sand they advance by pushing off against a solid region of sand that forms behind their flippers."

Details of the study were published online on February 10, 2010 in the journal Biology Letters. This research was supported by the Burroughs Wellcome Fund, National Science Foundation, and the Army Research Laboratory.

In collaboration with the Georgia Sea Turtle Center, biology graduate student Nicole Mazouchova studied the movement of sea turtle hatchlings of the species Caretta caretta at Jekyll Island on the coast of Georgia. She and research technician Andrei Savu worked from a mobile laboratory that contained a nearly three-foot-long trackway filled with dry Jekyll Island sand.

The trackway contained tiny holes in the bottom through which air could be blown. The air pulses elevated the granules and caused them to settle into a loosely packed solid state, allowing the researchers to closely control the density of the sand.

In addition to challenging hatchlings to traverse loosely packed sand in the trackway, the researchers also studied the turtles' movement on hard surfaces -- a sandpaper-covered board placed on top of the sand. Two high-speed cameras recorded the movements of the hatchlings along the trackway, and showed how the turtles altered their locomotion to move on different surfaces.

"We assumed that the turtles would perform best on rigid ground because it would not give way under their flippers, but our experiments showed that while the turtles' average speed on sand was reduced by 28 percent relative to hard ground, their maximal speeds were the same for both surfaces," noted Goldman.

The researchers' investigations showed that on the rigid sandpaper surface, the turtles anchored a claw located on their wrists into the sandpaper and propelled themselves forward. During the thrusting process, one of the turtle's shoulders rotated toward its body and its wrist did not bend, keeping the limb fully extended.

In contrast, on loosely packed sand, pressure from the thin edge of one of the turtle's flippers caused the limb to penetrate into the sand. The turtle's shoulder then rotated as the flipper penetrated until the flipper was perpendicular to the surface and the turtle's body lifted from the surface.

"The turtles dug into the loosely packed sand, lifted their bellies off the ground, lurched forward, stopped, and did it again," explained Goldman.

To extend their biological observations, Goldman and physics graduate student Nick Gravish designed an artificial flipper system in the laboratory. The flipper consisted of a thin aluminum plate that was inserted into and dragged along the trackway filled with Jekyll Island sand. Calibrated strain gauges mounted on the flipper provided force measurements during the dragging procedure.

"Our model revealed that a major challenge for rapid locomotion of hatchling sea turtles on sand is the balance between high speed, which requires large inertial forces, and the potential for failure through fluidization of the sand," explained Goldman. "We believe that the turtles modulate the amount of force they use to push into the sand so that it remains below the force required for the ground to break apart and become fluidlike."

Goldman and his team plan to conduct further field studies and laboratory experiments to determine if and how the turtles control their limb movements on granular media to avoid sand fluidization. They are also developing robots that move along granular media like the sea turtle hatchings.

"These research results are valuable for roboticists who want to know the minimum number of appendage features necessary to move effectively on land and whether they can just design a robot with a flat mitt and a claw like these turtles have," noted Goldman.

Text and Photo by Georgia Institute of Technology

Scientists have made synthetic 'sea shells' from a mixture of chalk and polystyrene cups -- and produced a tough new material that could make our homes and offices more durable.

A team of materials scientists and chemists have taken inspiration from sea shells found on the beach to create a composite material from dissimilar 'ingredients'.

Their technique could be used to make ceramics with high resistance to cracking -- which could in turn be used in crack-resistant building materials and bone replacements.

Writing in the journal Advanced Materials, scientists from The University of Manchester and The University of Leeds report that they have successfully reinforced calcium carbonate, or chalk, with polystyrene particles that are used to make drinks cups.

They have developed an effective method of combining calcite crystals with polystyrene particles -- and have found this makes the material more ductile compared to its original brittle form.

They report that the polystyrene also acts as a toughening agent, assisting the prevention of the growth of cracks.

Scientists also observed that when the reinforced material cracked, the polymer lengthened within the cracks -- a well-known mechanism for absorbing energy and enhancing toughness.

Researchers say their method allows the properties of the new material to be tweaked by selecting particles of different shapes, sizes and composition.

Dr Stephen Eichhorn from The School of Materials at The University of Manchester, said: "The mechanical properties of shells can rival those of man-made ceramics, which are engineered at high temperatures and pressures. Their construction helps to distribute stress over the structure and control the spread of cracks.

"Calcium carbonate is the main ingredient of chalk, which is very brittle and breaks easily when force is applied. But shells are strong and resistant to fracturing, and this is because the calcium carbonate is combined with proteins which bind the crystals together, like bricks in a wall, to make the material stronger and sometimes tougher.

"We have replicated nature's addition of proteins using polystyrene, to create a strong shell-like structure with similar properties to those seen in nature.

"Further research and testing is still needed but our research potentially offers a straightforward method of engineering new and tough chalk-based composite materials with a wide range of useful applications."

Text and Photo by University of Manchester

Giant plankton-eating fishes roamed the prehistoric seas for over 100 million years before they were wiped out in the same event that killed off the dinosaurs, new fossil evidence has shown.

An international team describe how new fossils from Asia, Europe and the US reveal a previously unknown dynasty of giant plankton-eating bony fishes that filled the seas of the Jurassic and Cretaceous periods, between 66-172 million years ago.

The team report their findings February 19 in Science.

'Today's giant plankton-feeders -- such as baleen whales, basking sharks and manta rays -- include the largest living vertebrate animals, so the fact that creatures of this kind were missing from the fossil record for hundreds of millions of years was always a mystery,' said Dr Matt Friedman of Oxford University's Department of Earth Sciences, an author of the report.

'We used to think that the seas were free of big filter feeders during the age of dinosaurs, but our discoveries reveal that a dynasty of giant fishes filled this ecological role in the ancient oceans for more than 100 million years.'

Several of the most important new fossils came from deposits in Kansas in the USA, with other remains from as far afield as Dorset and Kent in the UK, and Japan. Some members of this filter-feeding fish group are estimated to have been up to 9 meters long, a similar size to modern plankton-eating giants such as the basking shark.

'One of the reasons these big fishes were overlooked or misidentified lies in their anatomy,' said Dr Friedman. 'Over their evolutionary history, these fishes reduced the amount of bone in their skeletons, probably to save weight, with the consequence that most of their hard parts were easily scattered after death. As it turns out, the only parts you routinely find in the fossil record are their well-developed forefins.'

With few clues to go on, palaeontologists had argued that the owner of these isolated fins looked something like the modern-day swordfish. This changed when some of Dr Friedman's colleagues began cleaning a fossil that preserved skull bones along with the fins.

Dr Friedman said: 'Instead of finding a head with a long sword-like snout and jaws lined with predatory fangs, they found something completely different: long, toothless jaws supporting a gaping mouth, and long, rod-like bones that contributed to the huge gill arches needed to filter out enormous quantities of tiny plankton.' The team named this fish Bonnerichthys, honoring the Kansas family who discovered the fossil.

Remains of similar giant plankton-eating fishes had been known from much older rocks, but they were thought to be a short-lived and unsuccessful evolutionary experiment. 'As soon as we recognized that these animals had a longer history than anyone thought, I started examining museum collections and found more examples that had been overlooked or misidentified,' explained Dr Friedman. Revisiting previously collected fossils netted the team evidence that these fishes thrived for millions of years and colonized many parts of the globe.

Intriguingly the ancestors of large modern filter-feeders such as baleen whales and whale sharks only appeared after the extinction of Bonnerichthys and its relatives, suggesting that today's filter-feeders evolved to fill the ecological niche left behind by these plankton-eating contemporaries of the dinosaurs.

Text by University of Oxford Graphic by Robert Nicholls

Fossil corals, up to half a million years old, are providing fresh hope that coral reefs may be able to withstand the huge stresses imposed on them by today's human activity.

Reef ecosystems were able to persist through massive environmental changes imposed by sharply falling sea levels during previous ice ages, an international scientific team has found. This provides new hope for their capacity to endure the increasing human impacts forecast for the 21st century.

In the world's first study of what happened to coral reefs when ocean levels sank to their lowest recorded level -- over 120 meters below today's levels -- a study carried out on eight fossil reefs in Papua New Guinea's Huon Gulf region has concluded that a rich diversity of corals managed to survive, although they were different in composition to the corals under more benign conditions.

"Of course, sea levels then were falling -- and today they are rising. But if we want to know how corals cope with hostile conditions, then we have to study what happens under all circumstances," explains Professor John Pandolfi of the ARC Centre of Excellence for Coral Reef Studies and The University of Queensland. "We've seen what happens to corals in the past when sea levels rose and conditions were favorable to coral growth: we wanted to see what happened when they fell and conditions were adverse."

"When sea levels drop you get a catastrophic reduction in coral habitat and a loss of connectivity between reefs. Well, those circumstances are in some respects similar to what corals are experiencing today due to human impacts -- so there are useful parallels."

"Although it is little asked, the question of where reef species go when faced with extreme environmental situations is highly relevant for understanding their prospects of survival in the future -- and what we need to do to give them the best chance," Prof. Pandolfi suggests.

In the Huon region, the team found, coral reefs survived the hard times low of sea levels with as much richness of species -- but with a different composition to what they had during the good times. "As a rule the coral colonies during the period of low sea levels were closer to the sea floor and slower-growing in comparison with times of high sea levels."

"What we have found suggests that reef systems are able to survive adverse conditions given suitable shallow rocky habitat. An interesting finding of this study is that complex coral ecosystems were maintained during the less optimal periods of low sea level. These may have been critical to the re-establishment of nearby reefs once environmental conditions began to improve."

"The fossil record shows that reefs have been remarkably successful in surviving large environmental disturbances. However the combination of drastic environmental changes that we're seeing today, such as degraded water quality, depleted fish stocks, coral bleaching, ocean acidification and loss of habitat are unprecedented in the history of coral reefs. Although this study clearly highlights the resilience of reef ecosystems, it is important not to underestimate the magnitude of the challenges that reefs are currently facing. "

Prof. Pandolfi says we somehow have to find ways of preventing or offsetting each of these impacts if we expect our reefs to ride out the major climatic changes of the 21st century in as good condition as they have in the past.

Text by ARC Centre of Excellence in Coral Reef Studies Photo by John Pandolfi/ ARC Centre

The massive, 8.8-magnitude earthquake that struck Chile Feb. 27 occurred in an offshore zone that was under increased stress caused by a 1960 quake of magnitude 9.5, according to geologist Jian Lin of the Woods Hole Oceanographic Institution (WHOI).

The earthquake, some 300-500 times more powerful than the magnitude 7.0 quake in Haiti Jan. 12, ruptured at the boundary between the Nazca and South American tectonic plates. The temblor was triggered when the "subducting" Nazca plate was thrust under the South American plate, uplifting a large patch of the seafloor and prompting tsunami warnings throughout the Pacific Ocean. The two plates are converging at a rate of 80 mm per year, says Lin, "which is one of the fastest rates on Earth."

Lin and colleague Ross S. Stein of the U.S. Geological Survey in Menlo Park, Ca., have studied the region extensively, and alerted the scientific community to a build up of stress along the interface of the two plates in a 2004 paper in theJournal of Geophysical Research.

"In 2004, we calculated that the 1960 magnitude 9.5 earthquake has caused large stress increase on both the northern and southern ends of its rupture," said Lin. That quake, centered a few hundred kilometers south of Saturday's earthquake, was the largest instrumentally recorded earthquake in the world. It killed 1,655 people in southern Chile and unleashed a tsunami that crossed the Pacific, killing 61 people in Hawaii and 185 in Japan. Saturday's "quake picked up where the 1960 rupture ended in the north," Lin said.

"This story is quite similar to the Dec. 26, 2004 magnitude-9.0 Sumatra earthquake, which was followed by a magnitude 8.7 quake on its southern end on 28 March 2005," he said. "The only difference is that it took 50 years for the northern neighboring section of the 1960 [Chile] earthquake to rupture, while it took only 3 months for the southern adjacent segment to rupture in Sumatra.

"We do not yet have good enough science to say why one place took only 3 months and another took 50 years. But even 50 years is short enough [to fall within] in a person's lifetime. Thus, we should consider the earthquake interaction possibilities seriously."

In Haiti, Lin point out that and others have calculated that the Jan. 12 rupture has heightened stress further east along the Enriquillo Fault, thereby increasing chances of a quake in that region, which "comes within five kilometers of Port-au-Prince," he said.

The latest Chile quake, which had killed more than 700 people as of March 1, was centered some 65 miles west-southwest of Talca, Chile, about 21.7 miles below the ocean's surface, "relatively shallow for a subduction quake," said Lin. It struck about 200 miles southwest of Santiago, the country's capitol. Saturday's earthquake had a "much longer" rupture zone -- 500-600 km -- than that of the Haiti quake -- 35-50 km, Lin said.

"So why was the Haiti quake so much more catastrophic than the Chile quake?" he asked.

"First, as a nation, Chile is much better prepared for earthquakes than Haiti. People in Chile today still remember the pain of the 1960 quake," Lin said. In addition, coastal Chile has a history of other very large earthquakes. Since 1973, there have been 13 events of magnitude 7.0 or greater. Approximately 870 km to the north of the Feb. 27 earthquake is the source region of the magnitude 8.5 earthquake of November 1922. That great quake significantly killed several hundred people and caused severe property damage. The 1922 quake generated a 9-meter local tsunami that inundated the Chile coast near the town of Coquimbo; the tsunami also crossed the Pacific, washing away boats in Hilo harbor, Hawaii.

"In contrast, the last catastrophic earthquake in Haiti was 240 years ago," Lin said, "and thus few people were aware of a string of 'earthquake bombs' lying next to Port-au-Prince until Jan. 12.

"Second," he said, "the economy of Chile is much better than that of Haiti.Thus, building codes are better developed and enforced in Chile. The contrasts between the aftermaths of the Chile and Haiti quakes reminded us, once again, that 'earthquakes do not kill people, buildings do.'"

The Chile temblor dispatched tsunami waves onshore to Chile and across the Pacific Ocean toward Hawaii and the west coast of the US mainland, primarily California, and experts warned that tsunami waves were likely to hit Asian, Australian and New Zealand shores within 24 hours of the earthquake. Waves 6 feet (1.8 meters) above normal hit Talcahuano near Concepcion 23 minutes after the quake, and President Michelle Bachelet said a huge wave swept into a populated area in the Robinson Crusoe Islands, 410 miles (660 kilometers) off the Chilean coast. There were no immediate reports of major damage from the waves.

Though the predicted tsunami waves did reach Hawaii, California, New Zealand and other Pacific Rim regions, they proved to be relatively small and had minimal impact. "Even though the waves turned out to be not devastating," Lin said, "it was an important opportunity for communities in coastal regions to improve the preparedness for potential greater tsunamis in the future."

The WHOI research vessel Atlantis was operating off the coast of northern Chile when the magnitude 8.8 earthquake struck on Saturday. WHOI confirmed that R/V Atlantis and all on board are safe. There were no ill effects to R/V Atlantis or those on board from the quake or the subsequent tsunami.

R/V Atlantis has a scheduled port stop beginning on March 3, 2010, in Arica, Chile, which is on the northern coast of Chile. The WHOI Marine Operations Department is assessing the situation with their port agents to determine how or if that port stop will be affected.

Text and Graphic by Woods Hole Oceanographic Institution