In recent years, environmental engineers have sought to disinfect, depollute, and desalinate contaminated water using nanoscale particles of these active materials. Engineers call them nanoscavengers. The hitch from a technical standpoint is that it is nearly impossible to reclaim the nanoscavengers once in the water.

In a paper published online May 14 in the journal Nature Communications, an interdisciplinary team of engineers at Stanford University announces it has developed a new type of nanoscavenger with a synthetic core that is ultraresponsive to magnetism, allowing the easy and efficient recovery of virtually every one of the nanoscale purifiers.

"In contaminated water, nanoscavengers float around, randomly bumping into and killing bacteria or attaching themselves to the molecular pollutants they are after," said Shan Wang, the study's senior author and a professor of material science and engineering and jointly of electrical engineering.

"When the contaminants are either stuck to the nanoscavenger or dead, the magnet is turned on and the particles vanish."

Ultraresponsive to magnetism
The use of magnetism to recover nanoscavengers is not new. There are commercial technologies today that have fashioned nanoscavengers with a core of magnetic iron oxide surrounded by an active material, but these ingenious methods are less than perfect.

Iron oxide is not absolutely responsive to magnetism and too many nanoscavengers remain in the water for it to be considered safe for human use.

The Stanford advance replaces the iron oxide with a synthetic material. The Stanford core is, in reality, not a single material, but a disk of several layers - magnetic outer layers of the synthetic material sandwiched on either side of a titanium center, but with a twist.

"The magnetic moments of the two outer layers are opposed. The direction of the magnetic force in the top layer and the bottom layer point in opposite directions, effectively canceling the magnetic properties of the material," said Mingliang Zhang, a doctoral candidate in material science and engineering and co-first author of the study.

In their natural state, the new nanoscavengers are not magnetic and would not be attracted to another magnetic material. When the composite discs are exposed to a strong magnetic field, however, the magnetism of the two opposing fields turn into alignment, not just becoming magnetic but compounding the magnetic effect.

Side-by-side tests
In doing so, the nanoscavengers become ultraresponsive to magnetism, far more so than the base iron oxide used in today's technologies. The Stanford team has dubbed its advance with the oxymoronic name: "synthetic antiferromagnetic cores." The prefix anti- in this case means in opposite direction, not non-magnetic.

With a successful core created, the researchers then cap it with silver or titanium dioxide or another reactive material depending upon the contaminant they are targeting.

In live tests using synthetic-core, silver-capped nanoscavengers immersed in water tainted with E. coli bacteria, using a silver dosage of just 17 parts per million, the Stanford team was able to kill 99.9% of the bacteria in just 20 minutes. Better yet, they removed virtually all of the nanoscavengers in just five minutes of exposure to a permanent magnet.

Side-by-side tests of the effectiveness of the same magnet on iron oxide core nanoscavengers show a quick collection of about 20 percent of the nanoscavengers in the same five minutes, but then the effect plateaus. By minute 20, nearly eight-in-ten iron oxide core nanoscavengers remain in the water.

The one-pot solution
Having demonstrated a working prototype, the team is now building various iterations of their nanoscavengers with different reactive exteriors to target specific pollutants, as well as a new class of slightly larger nanoscavengers that might bear discrete bands of several different reactants.

"Our hope is to one day create a 'one-pot solution' that tackles water afflicted by a diverse mixture of contaminants. A purification technology like that could be very useful in recycling water in developing nations where water quality or in arid climates where water quantity are of critical importance," added Xing Xie, a doctoral candidate in civil and environmental engineering and co-first author of the paper.

Contributors to this study include Professor Craig Criddle of civil and environmental engineering, Associate Professor Yi Cui of materials science and engineering and Senior Research Engineer Mary Tang. The paper was published online May 14

]]> Mon, 20 MAY 2013 12:44:51 AEST Zurich, Switzerland (SPX) May 17, 2013 - How much all glaciers contribute to global sea-level rise has never been calculated before with this accuracy. An international group of researchers involving two geographers from the University of Zurich has confirmed that melting of glaciers caused about one third of the observed sea-level rise, while the ice sheets and thermal expansion of sea water account for one third each. So far, estimates on the contribution of glaciers have differed substantially.

Now 16 scientists from nine countries have compared the data from traditional measurements on the ground with satellite data from the NASA missions ICESat (Ice, Cloud and land Elevation Satellite) and GRACE (Gravity Recovery and Climate Experiment).

Combined with a glacier inventory that is available globally for the first time, the researchers were able to determine the glacier mass changes all over the world much more accurately than before.

"The extrapolations of local field measurements to large regions and entire mountain ranges traditionally applied sometimes overestimated the ice loss", describes UZH geographer Frank Paul the findings from the satellite measurements.

And his fellow colleague Tobias Bolch adds: "We are well aware of the weaknesses of the individual satellite methods. However, in highly glacierized regions the results obtained using the two different methods agree well. With the mix of methods that have now been tested and applied, we have come a major step closer to determining glacier mass loss with higher precision

Earlier estimates should be corrected
The results show that almost all glacier regions lost mass in the years 2003 to 2009, most of all in Arctic Canada, Alaska, coastal Greenland, the southern Andes and in the Himalayas.

By contrast, the glaciers in Antarctica - smaller ice masses that are not connected to the ice sheet - made scarcely any contribution to sea-level rise during this period. This finding deviates significantly from previous estimates, saying that the Antarctic glaciers caused around 30% of the global ice loss in the period from 1961 to 2004.

"However, neither the periods nor the data basis are directly comparable here", adds Bolch, "so we shouldn't make any premature conclusions in this respect."

The results published in "Science" have important consequences for past studies: Bolch and Paul conclude by recommending that "Earlier global estimates on the contribution of glaciers to sea-level rise should be revised again".

Alex S. Gardner, Geir Moholdt, J. Graham Cogley, Bert Wouters, Anthony A. Arendt, John Wahr, Etienne Bertier, Regine Hock, W. Tad Pfeffer, Georg Kaser, Stefan R. M. Ligtenberg, Tobias Bolch, Martin J. Sharp, Jon Ove Hagen, Michiel R. van den Broeke, Frank Paul. A Reconciled Estimate of Glacier Contributions to Sea Level Rise: 2003 to 2009. Science. May 17, 2013. Doi: 10.1126/science.1234532

]]> Mon, 20 MAY 2013 12:44:51 AEST Lausanne, Switzerland (SPX) May 14, 2013 - Researchers at EPFL present new evidence for the crucial role of algae in the survival of their coral hosts. Ultra-high resolution images reveal that the algae temporarily store nutrients as crystals, building up reserves for when supplies run low.

The relationship between corals and the microscopic algae they harbor is a classic example of biological symbiosis - the mutually beneficial interaction of two species.

But crucial details regarding their relationship have remained elusive until now. Using state-of-the-art imaging techniques, Anders Meibom and his team of researchers in the Laboratory for Biological Geochemistry have found new evidence on the vital role algae play in helping corals survive in environments where nutrients are scarce. Their findings were published in the journal mBio on May 16, 2013.

"Coral reefs are the jungles of our oceans - hotspots of biodiversity that easily outcompete all other marine ecosystems," says Christophe Kopp, first-author of the publication. Coral bleaching occurs when the colorful algae abandon their coral host because of environmental strains like rising sea temperatures. On their own, corals struggle to survive in tropical waters where nutrients are scarce, and persistent starvation can have irreversible effects.

While it is well known that algae help corals to assimilate certain nutrients, such as nitrogen from seawater, how this occurs, and to what extent the corals can get by on their own, are less clear.

To study how nitrogen-rich nutrients are taken up and processed by the corals and the algae that inhabit them, Meibom's research group teamed up with the Aquarium Tropicale Porte Doree in Paris to run a series of experiments.

There, they fed the corals nitrogen-rich compounds labeled with a heavy nitrogen isotope that they could later trace in the lab. Every few minutes, they extracted bits of coral, which they fixed and analyzed with a state-of-the-art isotopic imaging instrument, a so-called NanoSIMS.

Next, they assembled a timeline of how the nitrogen is processed by the corals and their resident algae by lining up the images of the samples extracted at different times. A combination of electron microscopy and mass spectrometry allowed them to study with unprecedented precision into which cellular compartments the heavier nitrogen isotopes had been incorporated.

Crystal food banks
The research revealed that the corals depend strongly on the algae to extract sufficient nutrients from the water. This was particularly true when the corals were exposed to nitrate, a compound that they are unable to process and assimilate on their own.

But most interestingly, the scientists observed that the algae act as tiny food banks. Their images revealed that the algae temporarily store the nitrogen in the form of uric acid crystals - a fact they later confirmed using crystallographic analysis. This way, the algae can stock up on nutrients when supply is abundant and draw on them when supply drops, leaching some out to their coral host.

Because coral reefs are at the foundation of immense economic activity, both as tourist magnets and as the habitats of some of the most productive fish populations, understanding their fate as the environment they inhabit changes is not only of ecological, but also of economic importance.

The research was performed in close collaboration with EPFL's Interdisciplinary Centre For Electron Microscopy (CIME), the Institute of Earth Science at the University of Lausanne, as well as the Aquarium Tropicale Porte Doree and the Museum d'Histoire Naturelle in Paris. The work is funded by an ERC Advanced grant and by a grant from the Swiss National Science Foundation.

]]> Mon, 20 MAY 2013 12:44:51 AEST Livermore CA (SPX) May 17, 2013 - The distortion of the ancient shoreline and flooding surface of the U.S. Atlantic Coastal Plain are the direct result of fluctuations in topography in the region and could have implications on understanding long-term climate change, according to a new study.

Sedimentary rocks from Virginia through Florida show marine flooding during the mid-Pliocene Epoch, which correlates to approximately 4 million years ago. Several wave-cut scarps (rock exposures), which originally would have been horizontal, are now draped over a warped surface with up to 60 meters variation.

Nathan Simmons of Lawrence Livermore National Laboratory and colleagues from the University of Chicago, Universite du Quebec a Montreal, Syracuse University, Harvard University and the University of Texas at Austin modeled the active topography using mantle convection simulations that predict the amplitude and broad spatial distribution of this distortion.

The results imply that dynamic topography and, to a lesser extent, glacial adjustment, account for the current architecture of the coastal plain and nearby shelf.

The results appear in the May 16 edition of Science Express, and will appear at a later date in Science Magazine.

"Our simulations of dynamic topography of the Eastern Seaboard have implications for inferences of global long-term sea-level change," Simmons said.

The eastern coast of the United States is considered an archetypal Atlantic-type or passive-type continental margin.

"The highlight is that mantle flow is a major component in distorting the Earth's surface over geologic time, even in so-called 'passive' continental margins," Simmons said.

"Reconstructing long-term global sea-level change based on stratigraphic relations must account for this effect. In other words, did the water level change or did the ground move? This could have implications on understanding very long-term climate change."

The mantle is not a passive player in determining long-term sea level changes. Mantle flow influences surface topography, through perturbations of the dynamic topography, in a manner that varies both spatially and temporally. As a result, it is difficult to invert for the global long-term sea level signal and, in turn, the size of the Antarctic Ice Sheet, using east coast shoreline data.

Simmons said the new results provide another powerful piece of evidence that mantle flow is intimately involved in shaping the Earth's surface and must be considered when attempting to unravel numerous long-term Earth processes such as sea-level variations over millions of years.

"Sleuthing Seismic Signals," Science and Technology Review, March 2009.

]]> Mon, 20 MAY 2013 12:44:51 AEST Bristol UK (SPX) May 17, 2013 - Limiting the amount of warming experienced by the world's oceans in the future could buy some time for tropical coral reefs, say researchers from the University of Bristol.

The study, published by the journal Geophysical Research Letters, used computer models to investigate how shallow-water tropical coral reef habitats may respond to climate change over the coming decades.

Dr Elena Couce and colleagues found that restricting greenhouse warming to three watts per square metre (equivalent to just 50-100 parts per million carbon dioxide, or approximately half again the increase since the Industrial Revolution) is needed in order to avoid large-scale reductions in reef habitat occurring in the future.

Shallow-water tropical coral reefs are amongst the most productive and diverse ecosystems on the planet. They are currently in decline due to increasing frequency of bleaching events, linked to rising temperatures and fossil fuel emissions.

Dr Couce said: "If sea surface temperatures continue to rise, our models predict a large habitat collapse in the tropical western Pacific which would affect some of the most biodiverse coral reefs in the world. To protect shallow-water tropical coral reefs, the warming experienced by the world's oceans needs to be limited."

The researchers modelled whether artificial means of limiting global temperatures - known as solar radiation 'geoengineering' - could help. Their results suggest that if geoengineering could be successfully deployed then the decline of suitable habitats for tropical coral reefs could be slowed.

They found, however, that over-engineering the climate could actually be detrimental as tropical corals do not favour overly-cool conditions. Solar radiation geoengineering also leaves unchecked a carbon dioxide problem known as 'ocean acidification'.

Dr Couce said: "The use of geoengineering technologies cannot safeguard coral habitat long term because ocean acidification will continue unabated. Decreasing the amount of carbon dioxide in the atmosphere is the only way to address reef decline caused by ocean acidification."

Dr Erica Hendy, one of the co-authors, added: "This is the first attempt to model the consequences of using solar radiation geoengineering on a marine ecosystem. There are many dangers associated with deliberate human interventions in the climate system and a lot more work is needed to fully appreciate the consequences of intervening in this way."

'Tropical coral reef habitat in a geoengineered, high-CO2 world' by E. Couce, P.J. Irvine, L. J. Gregorie, A. Ridgwell and E.J. Hendy in Geophysical Research Letters

]]> Mon, 20 MAY 2013 12:44:51 AEST Vancouver, Canada (SPX) May 17, 2013 - Climate change has been impacting global fisheries for the past four decades by driving species towards cooler, deeper waters, according to University of British Columbia scientists.

In a Nature study published this week, UBC researchers used temperature preferences of fish and other marine species as a sort of "thermometer" to assess effects of climate change on the world's oceans between 1970 and 2006.

They found that global fisheries catches were increasingly dominated by warm-water species as a result of fish migrating towards the poles in response to rising ocean temperatures.

"One way for marine animals to respond to ocean warming is by moving to cooler regions," says the study's lead author William Cheung, an assistant professor at UBC's Fisheries Centre. "As a result, places like New England on the northeast coast of the U.S. saw new species typically found in warmer waters, closer to the tropics.

"Meanwhile in the tropics, climate change meant fewer marine species and reduced catches, with serious implications for food security."

"We've been talking about climate change as if it's something that's going to happen in the distant future - our study shows that it has been affecting our fisheries and oceans for decades," says Daniel Pauly, principal investigator with UBC's Sea Around Us Project and the study's co-author. "These global changes have implications for everyone in every part of the planet."

A summary of the study is available here.

]]> Mon, 20 MAY 2013 12:44:51 AEST Bangkok (AFP) May 17, 2013 - Iran's firebrand President Mahmoud Ahmadinejad will address a forum on water security in Thailand next week, an embassy official said on Friday, just weeks before he stands down from the post.

His scheduled appearance in the northern Thai city of Chiang Mai from Sunday comes as Iran gears up for elections and as world powers press the Islamic republic over its suspected nuclear program and support for the Syrian regime.

Ahmadinejad, who is constitutionally barred from seeking a third straight term in next month's polls, is set to join regional leaders at the Asia-Pacific Water Summit, which will focus on water security and climate change.

"He will arrive on Sunday (May 19) in Chiang Mai," an Iranian embassy official in Bangkok told AFP, requesting anonymity.

Ahmadinejad -- who has irked the West since taking office in 2005 with his defiance of nuclear inspectors, fierce criticism of the US and Israel and tough response to opposition protests -- is set to address the summit on Monday.

The race for Iran's highest elected office has intensified since former president Akbar Hashemi Rafsanjani and top nuclear negotiator Saeed Jalili officially registered for the June 14 election.

Ahmadinejad has endorsed his controversial aide and ex-chief of staff Esfandiar Rahim Mashaei.

Nuclear talks between Iran and the UN atomic agency failed to reach a breakthrough yet again Wednesday, as the top US diplomat in separate six-party negotiations warned Washington's patience was wearing thin.

Iran has also come under pressure over the conflict tearing apart its close-ally Syria and has repeatedly rejected calls for foreign intervention in the increasingly brutal war.

]]> Mon, 20 MAY 2013 12:44:51 AEST Washington DC (SPX) May 16, 2013 - Microscopic algae that live within reef-forming corals scoop up available nitrogen, store the excess in crystal form, and slowly feed it to the coral as needed, according to a study published in mBio, the online open-access journal of the American Society for Microbiology.

Scientists have known for years that these symbiotic microorganisms serve up nitrogen to their coral hosts, but this new study sheds light on the dynamics of the process and reveals that the algae have the ability to store excess nitrogen, a capability that could help corals cope in their chronically low-nitrogen environment.

"It was a great surprise to find the nitrogen-rich crystals inside the algae," says corresponding author Anders Meibom of the Ecole Polytechnique Federale de Lausanne, Switzerland.

"It all makes perfect sense now. The algae suck up the ammonium and nitrate like a sponge when the concentration of these molecules increases, then store this nitrogen as uric acid crystals for later use."

Like all reef-forming corals, the species they studied, Pocillopora damicornis, is actually a symbiosis of two different organisms: the coral provides protection to a species of photosynthetic algae called dinoflagellates, which, in turn, provide sugars and nitrogen to the coral host.

The symbiosis allows the coral to thrive in clear, tropical waters that are naturally nutrient-poor. In many places, however, coral reefs are suffering from an excess of nutrients - pollution from sewage and fertilizers that impacts the symbiotic relationship and the health of coral in unknown ways.

To better understand these exchanges of materials and to determine how an excess of nutrients might affect the balance, the researchers exposed pieces of coral to varying concentrations of isotopically-labeled nitrogen-rich compounds.

Using the facilities at the Aquarium Tropicale Porte Doree in Paris, France, the scientists applied a relatively new analytic technique called nano-scale secondary ion mass-spectrometry (NanoSIMS) to follow the path of the nitrogen. NanoSIMS enabled them to visualize and quantify the uptake, movement, and accumulation of this labeled nitrogen within the coral.

When supplied with nitrogen in the form of ammonium, nitrate or aspartic acid the dinoflagellates responded by rapidly storing the nitrogen as crystals of uric acid within its cells.

But the dinoflagellates don't hang onto the nitrogen for long. Starting at about six hours after exposure, the microbes begin translocating nitrogen-rich compounds to the coral host, where the nitrogen is used in specific cellular compartments all over the surface layers of the coral.

This storage and release process helps explain how these corals get through the ups and downs of nitrogen concentrations, says Meibom. "This gives the coral-algae symbiosis a very efficient way to deal with strong fluctuations in nitrogen availability," writes Meibom.

"When the nitrogen availability suddenly becomes high, the algae can take-up large amounts of nitrogen on a timescale of a few hours, store it into crystals inside the algae cells and then release this stored nitrogen for metabolic processes and growth when the nitrogen levels become normal again."

To follow up on this work, Meibom says he and his colleagues are now studying how carbon-based nutrients are taken up and distributed in the same coral-algae symbiosis.

]]> Mon, 20 MAY 2013 12:44:51 AEST East Lansing MI (SPX) May 16, 2013 - Remains of endangered Hawaiian petrels - both ancient and modern - show how drastically today's open seas fish menu has changed. A research team, led by Michigan State University and Smithsonian Institution scientists, analyzed the bones of Hawaiian petrels - birds that spend the majority of their lives foraging the open waters of the Pacific.

They found that the substantial change in petrels' eating habits, eating prey that are lower rather than higher in the food chain, coincides with the growth of industrialized fishing.

The birds' dramatic shift in diet, shown in the current issue of the Proceedings of the National Academy of Sciences, leaves scientists pondering the fate of petrels as well as wondering how many other species face similar challenges.

"Our bone record is alarming because it suggests that open-ocean food webs are changing on a large scale due to human influence," said Peggy Ostrom, co-author and MSU zoologist. "Our study is among the first to address one of the great mysteries of biological oceanography - whether fishing has gone beyond an influence on targeted species to affect nontarget species and potentially, entire food webs in the open ocean."

Hawaiian petrels' diet is recorded in the chemistry of their bones. By studying the bones' ratio of nitrogen-15 and nitrogen-14 isotopes, researchers can tell at what level in the food chain the birds are feasting; generally, the larger the isotope ratio, the bigger the prey (fish, squid and crustaceans).

Between 4,000 and 100 years ago, petrels had high isotope ratios, indicating they ate bigger prey. After the onset of industrial fishing, which began extending past the continental shelves around 1950, the isotope ratios declined, indicating a species-wide shift to a diet of smaller fish and other prey.

Much research has focused on the impact of fishing near the coasts. In contrast, the open ocean covers nearly half of the Earth's surface. But due to a lack of historical records, fishing's impact on most open-ocean animal populations is completely unknown, said lead author Anne Wiley, formerly an MSU doctoral student and now a Smithsonian postdoctoral researcher.

"Hawaiian petrels spend the majority of their lives foraging over vast expanses of open ocean," she said. "In their search for food, they've done what scientists can only dream of. For thousands of years, they've captured a variety of fish, squid and crustaceans from a large portion of the North Pacific Ocean, and a record of their diet is preserved in their bones."

Addressing fishery impact through a chronology of bones is remarkable. Most marine animals die at sea, where their bones are buried on the ocean bottom. But after three decades of fossil collection in the Hawaiian Islands - the breeding grounds of the Hawaiian petrel - co-author Helen James of the Smithsonian Institution and her colleagues have amassed a collection of more than 17,000 ancient Hawaiian petrel bones.

"The petrels breed in burrows and caves where, if they die, their bones are likely to be preserved for a long time," James said. "It's fortuitous to find such a rich bone record for a rare oceanic predator."

Further studies are needed to explore how the shift down the food chain is affecting Hawaiian petrels. For a coastal seabird, however, a similar shift in diet has been associated with decreases in population - bad news for a federally protected bird.

Since petrels exploit fishing grounds from the equator to near the Aleutian Islands - an area larger than the continental United States - their foraging habits are quite telling. If petrels, signal flares for open-ocean food webs, have had a species-wide change in feeding habits, how many other predators around the world has fishing impacted? And what role do consumers play?

"What you choose to put on your dinner plate - that's your connection with the endangered Hawaiian petrel, and with many other marine species," Wiley said.

The research was funded by the National Science Foundation, MSU and the Smithsonian Institution.

]]> Mon, 20 MAY 2013 12:44:51 AEST Washington DC (SPX) May 16, 2013 - The impact of industrial fishing on coastal ecosystems has been studied for many years. But how it affects food webs in the open ocean?a vast region that covers almost half of the Earth's surface has not been very clear.

So a team of Smithsonian and Michigan State University scientists and their colleagues looked to the ancient bones of seabirds for answers, revealing some of the dramatic changes that have happened within open-ocean food webs since the onset of industrial fishing. The team's research is published this week in the Proceedings of the National Academy of Sciences.

Few records of species that live in the open ocean date back more than 60 years, and the sheer size of open-ocean regions makes their food webs difficult to study. The Hawaiian petrel (Pterodroma sandwichensis), a crow-sized oceanic bird, offered the team a solution. These birds range widely over the northeast Pacific, and their diets integrate food webs from that vast area.

What the petrels have eaten is recorded in the chemistry of their bones. By extracting protein from bones and feathers and studying stable isotopes of carbon and nitrogen in the protein, the scientists were able to assess the birds' diet and how it changed over centuries.

What they found from bones 100 to 4,000 years old were nitrogen isotope ratios that were consistently high, indicating a diet of relatively large prey. Those less than a century old, after industrial fishing started, had low ratios, revealing a shift to smaller fish, squid and other prey.

"The question is, have the effects of open-ocean fishing gone beyond targeted species, like tuna," said Anne Wiley, lead author, Smithsonian postdoctoral researcher and former MSU doctoral student.

"Our study is among the very first to show that it has, and because Hawaiian petrels eat such a wide variety of prey over a large area, our results suggest that fishery influence may be widespread and profound in the Pacific. Understanding the influence of fisheries on open-ocean food webs has been one of the great mysteries of biological oceanography."

The team's isotope records are unusual because they are from all the known populations of the species, which breed on different Hawaiian Islands. The records show that separate populations of Hawaiian petrels hunted in different areas of the open ocean for thousands of years.

The scientists revealed a foraging shift in multiple Hawaiian petrel populations, emphasizing that the petrels' diets changed across a very broad expanse of the ocean. This sudden shift in the past 100 years suggests a relatively rapid change in the composition of oceanic food webs in the Northeast Pacific.

"Conservation efforts for endangered seabirds take place mainly on land at breeding colonies where there are obvious threats like introduced predators," said Helen James, coauthor and research zoologist at Smithsonian's National Museum of Natural History. "Our study suggests we should pay more attention to the lives of these birds at sea."

Further studies are needed to explore how the change in foraging is affecting the Hawaiian petrel. Similar shifts down the food chain in other species have been associated with decreases in population size?potentially a bad sign for the Hawaiian petrel, which already has a small population restricted to the Hawaiian islands and is listed as "vulnerable" by the International Union for Conservation of Nature and Natural Resources.

]]> Mon, 20 MAY 2013 12:44:51 AEST Subscribe to our daily selection of space, military, environment and energy newsletters responseText http://visitor.constantcontact.com/manage/optin/ea?v=0016gbbKsaiGSpQFojVO8ZoHw%3D%3D