The Wildlife Conservation Society announced today that critically endangered alligators in China have a new chance for survival. The WCS's Bronx Zoo, in partnership with two other North American parks and the Department of Wildlife Conservation and Management of the State Forestry Administration of China, has successfully reintroduced alligators into the wild that are now multiplying on their own.

The alligator hatchlings—15 in number—are the offspring of a group of alligators that includes animals from the Wildlife Conservation Society's Bronx Zoo. The baby alligators represent a milestone for the 10-year effort to reintroduce the Chinese alligator on Chongming Island, located at the mouth of China's Yangtze River.

The announcement was made at the International Congress for Conservation Biology, convened by the Society for Conservation Biology in Beijing, China (July 11-16).

"We are grateful to our Chinese partners for their commitment to reintroduce Chinese alligators back into the wild," said Dr. Steven E. Sanderson, President and CEO of the Wildlife Conservation Society. "WCS has championed careful wildlife reintroductions for more than a century. The reintroduction of Chinese alligators is a great example of how WCS partners with governments and local communities around the world to save wildlife and wild places."

"This is fantastic news," said WCS researcher Dr. John Thorbjarnarson, one of the world's foremost experts on crocodilians and a participant in the project. "The success of this small population suggests that there's hope for bringing the Chinese alligator back to some parts of its former distribution."

Plans to reintroduce Chinese alligators started in 1999 with a survey conducted by WCS, the Anhui Forestry Bureau, and the East China Normal University in Anhui Province, the only remaining location where the reptiles are still found in the wild in what is a small fraction of the alligator's former range. The results of the survey were dire, with an estimate of fewer than 130 animals in a declining population.

An international workshop on the species was held in 2001, followed by recommendations for the reintroduction of captive bred alligators. The first three animals released in Hongxing Reserve of Xuancheng County in Anhui in 2003 were from the Anhui Research Center of Chinese Alligator Reproduction (ARCCAR).

To ensure the maximum genetic diversity for the effort, project participants imported 12 more animals to Changxing Yinjiabian Chinese Alligator Nature Reserve from North America, including four from the Bronx Zoo. From this group, three animals from the U.S. were released in 2007 along with three more alligators from Changxing. The alligators were given health examinations by veterinary professionals from WCS's Global Health Program and the Shanghai Wildlife Zoo and fitted with radio transmitters for remote monitoring before being released.

Experts reported that the reintroduced alligators successfully hibernated, and then in 2008, bred in the wild.

With a former range that covered a wide watershed area of East China, the Chinese alligator—or "tu long," which means "muddy dragon"—is now listed as "Critically Endangered" on IUCN's Red List of Threatened Species and is the most threatened of the 23 species of crocodilians in the world today. It is one of only two alligator species in existence (the other is the better known, and much better off, American alligator).

The Yangtze River, where the reintroduction of these alligators took place, is the third longest river in the world (after the Amazon and the Nile) and is China's most economically important waterway. The world's largest hydro-electric dam—the Three Gorges Dam—is also located on the river. The high levels of development along the river have become a challenge for native wildlife; in 2006, a comprehensive search for the Yangtze River dolphin, or baiji, didn't find any, although one isolated sighting of a dolphin was made in 2007.

Other participants in the project include the East China Normal University, Shanghai Forestry Bureau, Changxing Yinjiabian Chinese Alligator Nature Reserve, and Wetland Park of Shanghai Industrial Investment (Holdings) Co. Ltd.

The project is being supported by the Ocean Park Conservation Foundation, Hong Kong.

Researchers from the University of Southampton have drawn together 200 years' worth of oceanographic knowledge to investigate the distribution of a notorious deep-sea giant - the king crab. The results, published this week in the Journal of Biogeography, reveal temperature as a driving force behind the divergence of a major seafloor predator; globally, and over tens of millions of years of Earth's history.

In deep seas all over the world, around 100 species of king crabs live largely undiscovered. The fraction that have been found includes some weird and wonderful examples - Paralomis seagrantii has its eight walking legs and claws entirely covered in long fur-like setae; while related group Lithodes megacanthus grows to lengths of 1.5 metres, and has 15-20-cm long defensive spines covering its body. At temperatures of around 1- 4ºC, these crabs thrive in some of the colder waters on Earth; living and growing very slowly, probably to very old ages. Only in the cooler water towards the poles are king crabs found near the water surface - though temperatures found around some parts of the Antarctic (below 1ºC) are too extreme for their survival.

A paper, published 15 years ago in Nature is thought to show that king crabs evolved from shell-bound hermit crabs - similar to the familiar shoreline animals. Soft-bodied, but shell-free intermediate forms are found only in the shallow waters off Japan, Alaska, and Western Canada.

By looking at 200 years' worth of records from scientific cruises and museum collections, Sally Hall and Dr Sven Thatje from the University of Southampton's School of Ocean and Earth Science at the National Oceanography Centre, Southampton discovered that the soft-bodied forms can live at temperatures about ten degrees higher than the hard-bodied forms, but that both groups can only reproduce when temperature is between 1ºC up to 13-15ºC.

"It seems that most shallow-water representatives of this family are trapped in the coastal regions of the North Pacific because the higher sea surface temperatures further south prevent them from reproducing successfully and spreading," said Dr Thatje.

In order to leave this geographic bottleneck and spread around the world, the shallow water ancestors of current deep-sea groups had to go deep and adapt to the challenges of life in the deep sea. The process of adaptation to constant low temperatures (1-4ºC) prevailing in the deep sea seems to have narrowed the temperature tolerance range of the crabs where they have emerged to the surface waters in the Southern Hemisphere. With differences of only a couple of degrees in temperature affecting the distribution of the king crab, it is difficult to predict the consequences of range expansion in the warming waters around the Antarctic Peninsular region.

King crabs are of great commercial value, and fisheries are established in high latitude regions of both hemispheres. "Understanding their evolutionary history and ecology is key to supporting sustainable fisheries of these creatures," said research student Sally Hall. She adds: "Recent range extensions of king crabs into Antarctica, as well as that of the red king crab Paralithodes camtchaticus in the Barents Sea and along the coast off Norway emphasise the responsiveness of this group to rapid climate change."

This study reveals temperature as a driving force behind the speciation and radiation of a major seafloor predator globally and over tens of millions of years of Earth's history.

The study has been supported by the National Environment Research Council (UK) through a PhD studentship to Sally Hall, and a Research Grant from the Royal Society awarded to Dr Thatje.

Suspending a life in time is a theme that normally finds itself in the pages of science fiction, but now such ideas have become a reality in the annals of science.

Cornell ecologist Nelson Hairston Jr. is a pioneer in a field known loosely as "resurrection ecology," in which researchers study the eggs of such creatures as zooplankton -- tiny, free-floating water animals -- that get buried in lake sediments and can remain viable for decades or even centuries. By hatching these eggs, Hairston and others can compare time-suspended hatchlings with their more contemporary counterparts to better understand how a species may have evolved in the meantime.

The researchers take sediment cores from lake floors to extract the eggs; the deeper the egg lies in the core, the older it is. They then place the eggs in optimal hatching conditions, such as those found in spring in a temperate lake, and let nature take its course.

"We can resurrect them and discover what life was like in the past," said Hairston, who came to Cornell in 1985 and is a professor and chair of Cornell's Department of Ecology and Evolutionary Biology. "Paleo-ecologists study microfossils, but you can't understand much physiologically or behaviorally" with that approach, he said.

Hairston first became interested in the possibilities of studying dormant eggs in the late 1970s, when he was an assistant professor of zoology at the University of Rhode Island. There, he noticed that the little red crustaceans -- known as copepods -- in the pristine lake behind his Rhode Island home disappeared in the summer, only to return as larvae in the fall.

The observation prompted him to study why they disappear, research that revealed the copepods stay active under the ice in the winter, but they die out as their eggs lie dormant on the lake floor through the summer when the lake's fish are most active. When the fish become less active in the fall, larvae hatch from the eggs, and the copepods continue their life cycle.

This time suspension, where zooplankton pause their life cycles to avoid heavy predation or harsh seasonal and environmental conditions, also increases a species' local gene pool, with up to a century's worth of genetic material stored in a lake bed, Hairston said. When insects, nesting fish and boat anchors stir the mud, they can release old eggs that hatch and offer a wider variety of genetic material to the contemporary population.

In 1999 Hairston and colleagues published a paper in Nature that described how 40-year-old resurrected eggs could answer whether tiny crustaceans called Daphnia in central Europe's Lake Constance had evolved to survive rising levels of toxic cyanobacteria, known as blue-green algae. In the 1970s, phosphorus levels from pollution rose in the lake, increasing the numbers of cyanobacteria. The researchers hatched eggs from the 1960s and found they could not survive the toxic lake conditions, but Daphnia from the 1970s had adapted and survived.

Hairston and colleagues have organized a resurrection ecology symposium in September 2009, in Herzberg, Switzerland, to bring together researchers in this growing new field.

New evidence for ice-free summers with intermittent winter sea ice in the Arctic Ocean during the Late Cretaceous – a period of greenhouse conditions - gives a glimpse of how the Arctic is likely to respond to future global warming.

Records of past environmental change in the Arctic should help predict its future behaviour. The Late Cretaceous, the period between 100 and 65 million years ago leading up to the extinction of the dinosaurs, is crucial in this regard because levels of carbon dioxide (CO2) were high, driving greenhouse conditions. But scientists have disagreed about the climate at this time, with some arguing for low Arctic late Cretaceous winter temperatures (when sunlight is absent during the Polar night) as against more recent suggestions of a somewhat milder 15°C mean annual temperature.

Writing in Nature, Dr Andrew Davies and Professor Alan Kemp of the University of Southampton's School of Ocean and Earth Science based at the National Oceanography Centre, Southampton, along with Dr Jennifer Pike of Cardiff University take this debate a step forward by presenting the first seasonally resolved Cretaceous sedimentary record from the Alpha Ridge of the Arctic Ocean.

The scientists analysed the remains of diatoms – tiny free-floating plant-like organisms - preserved in late Cretaceous marine sediments. In modern oceans, diatoms play a dominant role in the 'biological carbon pump' by which carbon dioxide is drawn down from the atmosphere through photosynthesis and a proportion of it exported to the deep ocean. Unfortunately, the role of diatoms in the Cretaceous oceans has until now been unclear, in part because they are often poorly preserved in sediments.

But the researchers struck lucky. "With remarkable serendipity," they explain, " successive US and Canadian expeditions that occupied floating ice islands above the Alpha Ridge of the Arctic Ocean, recovered cores containing shallow buried upper Cretaceous diatom ooze with superbly preserved diatoms." This has allowed them to conduct a detailed study of the diatom fossils using sophisticated electron microscopy techniques. In the modern ocean, scientists use floating sediment traps to collect and study settling material. These electron microscope techniques that have been pioneered by Professor Kemp's group at Southampton have unlocked a 'palaeo-sediment trap' to reveal information about Late Cretaceous environmental conditions.

They find that the most informative sediment core samples display a regular alternation of microscopically thin layers composed of two distinctly different diatom assemblages, reflecting seasonal changes. Their analysis clearly demonstrates that seasonal blooming of diatoms was not related to the upwelling of nutrients, as has been previously suggested. Rather, production occurred within a stratified water column, indicative of ice-free summers. These summer blooms comprised specially adapted species resembling those of the modern North Pacific Subtropical Gyre, or preserved in relatively recent organically rich Mediterranean sediments called 'sapropels'.

The sheer number of diatoms found in the Late Cretaceous sediment cores indicates exceptional abundances equalling modern values for the most productive areas of the Southern Ocean. "This Cretaceous production, dominated by diatoms adapted to stratified conditions of the polar summer may also be a pointer to future trends in the modern ocean," say the researchers: "With increasing CO2 levels and global warming giving rise to increased ocean stratification, this style of (marine biological) production may become of increasing importance."

However, thin accumulations of earthborn sediment within the diatom ooze are consistent with the presence of intermittent sea ice in the winter, a finding that supports "a wide body of evidence for low Arctic late Cretaceous winter temperatures rather than recent suggestions of a 15C mean annual temperature at this time." The size distribution of clay and sand grains in the sediment points to the formation of sea ice in shallow coastal seas during autumn storms but suggests the absence of larger drop-stones suggests that the winters, although cold, were not cold enough to support thick glacial ice or large areas of anchored ice.

Commenting on the findings, Professor Kemp said: "Although seasonally-resolved records are rarely preserved, our research shows that they can provide a unique window into past Earth system behaviour on timescales immediately comparable and relevant to those of modern concern."

Davies, A., Kemp, A. S. & Pike, J. Late Cretaceous seasonal ocean variability from the Arctic. Nature 460, 254-258 (9 July 2009).

http://www.nature.com/nature/journal/v460/n7252/full/nature08141.html

The research was supported by the Natural Environment Research Council.

Stirling Energy Systems (SES) and Tessera Solar recently unveiled four newly designed solar power collection dishes at Sandia National Laboratories’ National Solar Thermal Test Facility (NSTTF). Called SunCatchers™, the new dishes have a refined design that will be used in commercial-scale deployments of the units beginning in 2010.

“The four new dishes are the next-generation model of the original SunCatcher system. Six first-generation SunCatchers built over the past several years at the NSTTF have been producing up to 150KW [kilowatts] of grid-ready electrical power during the day,” says Chuck Andraka, the lead Sandia project engineer. “Every part of the new system has been upgraded to allow for a high rate of production and cost reduction.”

Sandia’s concentrating solar-thermal power (CSP) team has been working closely with SES over the past five years to improve the system design and operation.

The modular CSP SunCatcher uses precision mirrors attached to a parabolic dish to focus the sun’s rays onto a receiver, which transmits the heat to a Stirling engine. The engine is a sealed system filled with hydrogen. As the gas heats and cools, its pressure rises and falls. The change in pressure drives the piston inside the engine, producing mechanical power, which in turn drives a generator and makes electricity.

The new SunCatcher is about 5,000 pounds lighter than the original, is round instead of rectangular to allow for more efficient use of steel, has improved optics, and consists of 60 percent fewer engine parts. The revised design also has fewer mirrors — 40 instead of 80. The reflective mirrors are formed into a parabolic shape using stamped sheet metal similar to the hood of a car. The mirrors are made by using automobile manufacturing techniques. The improvements will result in high-volume production, cost reductions, and easier maintenance.

Among Sandia’s contributions to the new design was development of a tool to determine how well the mirrors work in less than 10 seconds, something that took the earlier design one hour.

“The new design of the SunCatcher represents more than a decade of innovative engineering and validation testing, making it ready for commercialization,” says Steve Cowman, Stirling Energy Systems CEO. “By utilizing the automotive supply chain to manufacture the SunCatcher, we’re leveraging the talents of an industry that has refined high-volume production through an assembly line process. More than 90 percent of the SunCatcher components will be manufactured in North America.”

In addition to improved manufacturability and easy maintenance, the new SunCatcher minimizes both cost and land use and has numerous environmental advantages, Andraka says.

“They have the lowest water use of any thermal electric generating technology, require minimal grading and trenching, require no excavation for foundations, and will not produce greenhouse gas emissions while converting sunlight into electricity,” he says.

Tessera Solar, the developer and operator of large-scale solar projects using the SunCatcher technology and sister company of SES, is building a 60-unit plant generating 1.5 MW (megawatts) by the end of the year either in Arizona or California. One megawatt powers about 800 homes. The proprietary solar dish technology will then be deployed to develop two of the world’s largest solar generating plants in Southern California with San Diego Gas & Electric in the Imperial Valley and Southern California Edison in the Mojave Desert, in addition to the recently announced project with CPS Energy in West Texas. The projects are expected to produce 1,000 MW by the end of 2012.

Last year one of the original SunCatchers set a new solar-to-grid system conversion efficiency record by achieving a 31.25 percent net efficiency rate, toppling the old 1984 record of 29.4.

Could the cars and laptops of the future be fuelled by old chip fat? Engineers at the University of Leeds believe so, and are developing an energy efficient, environmentally-friendly hydrogen production system. The system enables hydrogen to be extracted from waste materials, such as vegetable oil and the glycerol by-product of bio-diesel. The aim is to create the high purity hydrogen-based fuel necessary not only for large-scale power production, but also for smaller portable fuel cells.

Dr Valerie Dupont from the School of Process, Environmental and Materials Engineering (SPEME) says: “I can foresee a time when the processes we are investigating could help ensure that hydrogen is a mainstream fuel.

“We are investigating the feasibility of creating a uniquely energy efficient method of hydrogen production which uses air rather than burners to heat the raw product. Our current research will improve the sustainability of this process and reduce its carbon emissions.”

A grant of over £400k has been awarded to the University by the Engineering and Physical Sciences Research Council (EPSRC) within a consortium of 12 institutions known as SUPERGEN Sustainable Hydrogen Delivery.

Hydrogen is widely considered to be a potential replacement for fossil fuels, but it is costly to extract. There are also often high levels of greenhouse gases emitted during conventional methods of production.

The system being developed at Leeds – known as Unmixed and Sorption-Enhanced Steam Reforming - mixes waste products with steam to release hydrogen and is potentially cheaper, cleaner and more energy efficient.

A hydrocarbon-based fuel from plant or waste sources is mixed with steam in a catalytic reactor, generating hydrogen and carbon dioxide along with excess water. The water is then easily condensed by cooling and the carbon dioxide is removed in-situ by a solid sorbent material.

Dr Dupont says: “It’s becoming increasingly necessary for scientists devising new technologies to limit the amount of carbon dioxide they release. This project takes us one step closer to these goals – once we have technologies that enable us to produce hydrogen sustainably, the infrastructure to support its use will grow.”

“We firmly believe that these advanced steam reforming processes have great potential for helping to build the hydrogen economy. Our primary focus now is to ensure the materials we rely on - both to catalyse the desired reaction and to capture the carbon dioxide – can be used over and over again without losing their efficacy.”

For the first time, NOAA scientists have demonstrated that tsunamis in the open ocean can change sea surface texture in a way that can be measured by satellite-borne radars. The finding could one day help save lives through improved detection and forecasting of tsunami intensity and direction at the ocean surface.

“We’ve found that roughness of the surface water provides a good measure of the true strength of the tsunami along its entire leading edge. This is the first time that we can see tsunami propagation in this way across the open ocean,” said lead author Oleg Godin of NOAA’s Earth System Research Laboratory and the Cooperative Institute for Research in Environmental Sciences, in Boulder, Colo.

Large tsunamis crossing the open ocean stir up and darken the surface waters along the leading edge of the wave, according to the study. The rougher water forms a long, shadow-like strip parallel to the wave and proportional to the strength of the tsunami. That shadow can be measured by orbiting radars and may one day help scientists improve early warning systems. The research is published online this week in the journal, Natural Hazards and Earth System Sciences.

The new research challenges the traditional belief that tsunamis are too subtle in the open ocean to be seen at the surface. The findings confirm a theory, developed by Godin and published in 2002-05, that tsunamis in the deep ocean can be detected remotely through changes in surface roughness.

In 1994, a tsunami shadow was captured by video from shore moments before the wave struck Hawaii. That observation and earlier written documentation of a shadow that accompanied a deadly tsunami on April 1, 1946, inspired Godin to develop his theory. He tested the theory during the deadly December 26, 2004, Indian Ocean tsunami, the result of the Sumatra-Andaman earthquake.

Godin and colleagues analyzed altimeter measurements of the 2004 tsunami from NASA’s Jason-1 satellite. The data revealed clear evidence of an increased surface roughness along the leading edge of the tsunami as it passed across the Indian Ocean between two and six degrees south latitude.

Tsunamis can be detected in several ways. One detection method uses a buoy system that warns coastal communities in the United States of an approaching tsunami. NOAA’s Deep-ocean Assessment and Reporting of Tsunamis (DART) early warning system uses sensors on the ocean floor to measure changes in pressure at each location. The DART network of 39 stations extends around the perimeter of the Pacific Ocean and along the western edge of the North Atlantic Ocean and Gulf of Mexico. The technology provides accurate, real-time information on the amplitude, over time, of an approaching tsunami. NOAA's tsunami warning centers then use this information to forecast the tsunami's impact on coastlines.

A second method uses space-borne altimeters to detect tsunamis by measuring small changes in sea surface height. Only a handful of these instruments are in orbit and the observations are limited to points along a line.

The new study presents a third way to detect tsunamis — by changes in the texture of the surface water across a wide span of the open ocean.

Godin’s research confirmed his theory that a tsunami wave roughens the surface water through air-sea interaction. First the leading edge of the tsunami wave stirs up the surface winds. Those same winds, which become more chaotic than the wave itself, then churn the surface waters along the slope of the wave.

Because rough water is darker than smooth water, a contrast forms between the dark, rough water of the wave and the bright, smooth water on either side of it. Common scientific instruments, called microwave radars and radiometers, are able to detect this contrast, known as a tsunami shadow.

When orbiting the Earth, microwave radars and radiometers can observe a band of ocean surface hundreds of kilometers wide and thousands of kilometers long. If programmed correctly to observe sea surface roughness, they could potentially map an entire tsunami, said Godin.

The paper, “Variations in sea surface roughness induced by the 2004 Sumatra-Andaman tsunami,” by O. A. Godin, V. G. Irisov, R. R. Leben, B. D. Hamlington, and G. A. Wick, appears in Natural Hazards and Earth System Sciences, a journal of the European Geosciences Union.

Plant roots provide the crops we eat with water, nutrients and anchorage. Understanding how roots grow and how hormones control that growth is crucial to improving crop yields, which will be necessary to address food security and produce better biofuels.

Now an international group of scientists, led by the Centre for Plant Integrative Biology at The University of Nottingham, has shed light on how a plant hormone is crucial in controlling the growth of plant roots.

Plant growth is driven by an increase in two factors: the number of cells, and their size. It is already known that the plant hormone gibberellin controls how root cells elongate as the root grows in the model plant Arabidopsis thaliana. Now a paper appearing in Current Biology describes for first time how this hormone also regulates the number of cells in the root in order to control root growth.

Gibberellin normally acts by signaling the removal of proteins which repress growth, and so promotes root cell production. The new research shows that mutant plants that do not produce gibberellin are unable to increase their cell production rate and the size of the root meristem, the zone of cell proliferation.

Plants in which the cells in the meristem were made to express a mutant version of the growth-repressing protein GAI not degraded by gibberellin showed disrupted cell proliferation. Expressing this mutant form, gai, in only one tissue, the endodermis (the innermost layer of the root cortex of a plant), was sufficient to stop the meristem enlarging. In effect, the rate of expansion of dividing endodermal cells dictates the equivalent rate in other tissues.

This research was headed by Dr Susana Ubeda-Tomás and Professor Malcolm Bennett of the Centre for Plant Integrative Biology, in collaboration with scientists in Nottingham, Cambridge, Edinburgh, Spain, Belgium and Sweden.

Professor Malcolm Bennett, Biology Director for the Centre for Plant Integrative Biology and Professor of Plant Sciences in the Division of Plant and Crop Sciences, said: “We have shown that gibberellin plays a crucial role in controlling the size of the root meristem, and that it is the endodermis which sets the pace for expansion rates in the other tissues.

“Understanding precisely how hormones regulate plant growth is one of the key areas of fundamental plant biology which will underpin crop improvements in the future.”

Hot town, summer in the city. When it comes to air-quality advisories, city residents are no strangers, especially during the dog days of summer. But smog is made up of an array of air pollutants, including the mad hatter’s muse, mercury. One Ryerson University researcher has found that summer is the peak season for this atmospheric toxin, and that higher levels of mercury species exist in the urban atmosphere as compared to rural regions.

Julia Lu is an Associate Professor in Ryerson’s Department of Chemistry and Biology, where she conducts research identifying and quantifying different forms of trace metals in the environment. Her main focus, however, is mercury, an element that can be found in many places, which explains why Dr. Lu’s work has involved such diverse locales as the Canadian Arctic and, more recently, Toronto, Canada’s largest city.

One of many contributing poor air factors, mercury is well-known for its toxic effects on the environment and human health. Airborne mercury’s greatest threat is that it will settle into the surface environment and be converted into the much more toxic organomercury species which can be accumulated and magnified up the food chain, reaching our dinner table through fish and shellfish consumption.

Mercury measurements in the urban atmosphere have been very limited in contrast to rural and remote areas. So, in order to investigate this particular field, Dr. Lu and her then-graduate students Xinjie Song and Irene Cheng mounted specialized equipment – including air sampling units and a meteorological station – atop a three-storey building on Ryerson’s campus in downtown Toronto. From there, the team simultaneously measured three types of mercury: atmospheric gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and mercury associated with particles with sizes less than 2.5 micrometres.

In addition to finding higher mercury levels in urban areas, the team discovered those levels seemed to be affected by human-produced emissions, rather than chemical and photochemical reactions in the environment. Finally, while the concentrations of all mercury species varied during the year – and were lower in the winter – the amount of GEM spiked in June. A concern, according to Dr. Lu, because GEM stays in the atmosphere longer and travels further than its chemical counterparts. The result, she believes, is a global-scale problem.

“Sometimes the spikes were as high as what you would find near point sources of mercury,” says Dr. Lu, citing coal-powered and metal-processing plants as examples.“We need to further our understanding of how cities contribute to the mercury problem. And it’s not just GEM that requires attention. Other forms of mercury stay in the atmosphere for a shorter duration and therefore negatively impact local and regional areas.”

As next steps, Dr. Lu is working to pinpoint sources of mercury in the urban environment. To help accomplish her objective, Dr. Lu has moved her measurement equipment to the top of a taller building on campus and has outfitted a car that will drive around and measure mercury at street-level. At the same time, a group of more than 10 Ryerson researchers are developing a weather network that is trying to figure out air-flow patterns in the city, which will also benefit Dr. Lu’s research.

Global warming may exact a toll on salt marshes in New England, but new research shows that one key constituent of marshes may be especially endangered.

Pannes are waterlogged, low-oxygen zones of salt marshes. Despite the stresses associated with global warming, pannes are "plant diversity hotspots," according to Keryn Gedan, a graduate student and salt marsh expert at Brown University. At least a dozen species of plants known as forbs inhabit these natural depressions, Gedan said. The species include the purple flower-tipped plants Limonium nashii (sea lavender), the edible plant Salicornia europaea (pickleweed) and Triglochin maritima, a popular food for Brent and Canada geese as well as ducks and other migratory waterfowl.

Gedan and her adviser, Mark Bertness, chair of the Ecology and Evolutionary Biology Department at Brown, decided to find out how global warming may affect pannes. In a series of experiments published in Ecology Letters, the pair subjected plots of forb pannes to air as much as 3.3 degrees Celsius (about 6 degrees Fahrenheit) warmer than the surrounding area.

They found that the plants in the test plots responded initially by growing more but then began a rapid die-off. As they died, they were replaced by a salt marsh grass, Spartina patens. At two sites — Nag Creek (Prudence Island, Rhode Island), and Little River (Maine) — the forbs covered less than 10 percent of the plot, from 50 percent originally, in tests that spanned the summer from 2004 to 2006. At the third site, Drakes Island (Maine), the forb pannes cover decreased from 50 percent of the plot to 44 percent (a 12-percent decline) in just the summer of 2007.

The researchers believe the forbs disappeared due to changes in the plant-water balance in the zone. What that means, Gedan explained, is the warmer air causes the forbs to take in more water, thus making the area less waterlogged and more hospitable to an invasion by Spartina patens, which prefers less water-soaked conditions.

"The forbs basically engineer themselves out of their habitat by making it more favorable for their competitor," said Gedan, the paper's lead author.

In New England, pannes range from Connecticut, where they make up less than 10 percent of a salt marsh's area, to Maine, where they can comprise some 40 percent of the salt marsh ecosystem, according to Gedan.

The Brown experiments "demonstrate that New England salt marsh pannes are extremely sensitive to temperature increases and will be driven to local and regional extinction with the temperature increases expected to occur in New England over the next century," Bertness said.

The scientists are unsure how other variables associated with climate change, such as sea-level rise, may affect pannes. Gedan said higher sea levels would help pannes, because forbs fare well in areas inundated by water. On the other hand, she added, the higher concentrations of carbon dioxide also expected to occur would accelerate forbs' use of water, which may open them up to competition from other plant species.

"How all these things interact, we don't really know," Gedan said. "But we know that with [higher] temperatures, these changes happen rapidly."

Funding came from the Environmental Protection Agency Science to Achieve Results (STAR) Graduate Fellowship Program, the National Oceanic and Atmospheric Administration (NOAA) National Estuarine Research Reserve System, and Rhode Island Sea Grant.

No one knows exactly how much Earth's climate will warm due to carbon emissions, but a new study suggests scientists' best predictions about global warming might be incorrect.

The study, which appears in Nature Geoscience, found that climate models explain only about half of the heating that occurred during a well-documented period of rapid global warming in Earth's ancient past. The study, which was published online July 13, contains an analysis of published records from a period of rapid climatic warming about 55 million years ago known as the Palaeocene-Eocene thermal maximum, or PETM.

"In a nutshell, theoretical models cannot explain what we observe in the geological record," said oceanographer Gerald Dickens, a co-author of the study and professor of Earth science at Rice University. "There appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models."

During the PETM, for reasons that are still unknown, the amount of carbon in Earth's atmosphere rose rapidly. For this reason, the PETM, which has been identified in hundreds of sediment core samples worldwide, is probably the best ancient climate analogue for present-day Earth.

In addition to rapidly rising levels of atmospheric carbon, global surface temperatures rose dramatically during the PETM. Average temperatures worldwide rose by about 7 degrees Celsius -- about 13 degrees Fahrenheit -- in the relatively short geological span of about 10,000 years.

Many of the findings come from studies of core samples drilled from the deep seafloor over the past two decades. When oceanographers study these samples, they can see changes in the carbon cycle during the PETM.

"You go along a core and everything's the same, the same, the same, and then suddenly you pass this time line and the carbon chemistry is completely different," Dickens said. "This has been documented time and again at sites all over the world."

Based on findings related to oceanic acidity levels during the PETM and on calculations about the cycling of carbon among the oceans, air, plants and soil, Dickens and co-authors Richard Zeebe of the University of Hawaii and James Zachos of the University of California-Santa Cruz determined that the level of carbon dioxide in the atmosphere increased by about 70 percent during the PETM.

That's significant because it does not represent a doubling of atmospheric carbon dioxide. Since the start of the industrial revolution, carbon dioxide levels are believed to have risen by about one-third, largely due to the burning of fossil fuels. If present rates of fossil-fuel consumption continue, the doubling of carbon dioxide from fossil fuels will occur sometime within the next century or two.

Doubling of atmospheric carbon dioxide is an oft-talked-about threshold, and today's climate models include accepted values for the climate's sensitivity to doubling. Using these accepted values and the PETM carbon data, the researchers found that the models could only explain about half of the warming that Earth experienced 55 million years ago.

The conclusion, Dickens said, is that something other than carbon dioxide caused much of the heating during the PETM. "Some feedback loop or other processes that aren't accounted for in these models -- the same ones used by the IPCC for current best estimates of 21st Century warming -- caused a substantial portion of the warming that occurred during the PETM."

Scientists at NOAA's National Centers for Coastal Ocean Science and the Monterey Bay Aquarium Research Institute (MBARI) have successfully conducted the first remote detection of a harmful algal species and its toxin below the ocean's surface. The achievement was recently reported in the June issue of Oceanography.

This achievement represents a significant milestone in NOAA's effort to monitor the type and toxicity of harmful algal blooms (HABs). HABs are considered to be increasing not only in their global distribution, but also in the frequency, duration, and severity of their effects. HABs damage coastal ecosystem health and pose threats to humans as well as marine life. Climate change is expected to exacerbate this trend, since many critical processes that govern HABs dynamics, such as water temperature and ocean circulation, are influenced by climate.

A MBARI-designed robotic instrument called the Environmental Sample Processor, or 'ESP,' designed as a fully-functional analytical laboratory in the sea, lets researchers collect the algal cells and extract the genetic information required for organism identification as well as the toxin needed to assess the risk to humans and wildlife. The ESP then conducts specialized, molecular-based measurements of species and toxin abundance, and transmits results to the laboratory via radio signals.

"This represents the first autonomous detection of both a HAB species and its toxin by an underwater sensor," notes Greg Doucette, Ph.D., a research oceanographer at NOAA's Center for Coastal Environmental Health and Biomolecular Research laboratory in Charleston, S.C. "It allows us to determine not only the organism causing a bloom, but also the toxicity of the event, which ultimately dictates whether it is a threat to the public and the ecosystem."

For the first demonstration of the ESP's ability to detect HABs and their toxins, Doucette and his MBARI colleague, Chris Scholin, Ph.D., targeted certain members of the algal genus Pseudo-nitzschia and their neurotoxin, domoic acid in Monterey Bay, Calif.

Pseudo-nitzschia and domoic acid have been a concern in the Monterey Bay area for well over a decade. In 1991, the first U.S. outbreak of domoic acid poisoning was documented in Monterey Bay. This outbreak resulted in the unusual deaths of numerous pelicans and cormorants that ingested sardines and anchovies, which had accumulated the domoic acid by feeding on a bloom of the toxic algae.

In the spring of 1998, a mass mortality of sea lions in and around the Monterey Bay area was attributed to the sea lions' feeding on domoic acid contaminated anchovies. Since that time, Pseudo-nitzschia and domoic acid have appeared on virtually an annual basis in California coastal waters and are the objects of an intensive statewide monitoring program run by the California Dept. of Public Health. Humans also can be affected by the toxin through consumption of contaminated seafood such as shellfish.

"Our public health monitoring program is one of the many groups that can benefit directly from the ESP technology and ability to provide an early warning of impending bloom activity and toxicity," said Gregg Langlois, director of the state of California's Marine Biotoxin Monitoring Program. "This is critical information for coastal managers and public health officials in mitigating impacts on the coastal ecosystem, since the toxicity of these algae can vary widely from little or no toxicity to highly toxic."

Beyond improving forecasting of HABs, this research will contribute to the rapidly emerging U.S. Integrated Ocean Observing System (IOOS) by adding a new way to make coastal ocean observations.

Varroa mites could literally be walking into a trap—thanks to a new attractant developed by Agricultural Research Service (ARS) scientists in Gainesville, Fla.

The 1/16-inch long parasite, Varroa destructor, is a top pest of honey bees nationwide, hindering the beneficial insects' ability to pollinate almonds, blueberries, apples, zucchini and many other flowering crops.

At the ARS Chemistry Research Unit in Gainesville, research leader Peter Teal and colleagues are testing a bait-and-kill approach using sticky boards and natural chemical attractants called semiochemicals.

In nature, Varroa mites rely on these semiochemicals to locate—and then feed on—the bloodlike hemolymph of both adult honey bees and their brood. Severe infestations can decimate an affected hive within several months—and rob the beekeeper of profits from honey or pollinating services. But in this case, the mites encounter a more heady bouquet of honey bee odors that lure the parasites away from their intended hosts and onto the sticky boards, where they starve.

In preliminary tests, 35 to 50 percent of mites dropped off the bees when exposed to the attractants. Free-roving mites found the semiochemicals even more attractive, according to Teal.

Moreover, the extra dose of semiochemicals wafting through hives didn't appear to significantly interfere with the honey bees' normal behavior or activity, added Teal who, along with postdoctoral associate Adrian Duehl and University of Florida collaborator Mark Carroll, reported the results this past January at the 2009 North American Beekeeping Conference in Reno, Nev.

The team hopes ARS' patenting of the Varroa mite attractants will encourage an industrial partner to develop the technology further.

We live in a hierarchical Universe where small structures join into larger ones. Earth is a planet in our Solar System, the Solar System resides in the Milky Way Galaxy, and galaxies combine into groups and clusters. Clusters are the largest structures in the Universe, but sadly our knowledge of them is not proportional to their size.

Researchers have long known that the gas in the centers of some galaxy clusters is rapidly cooling and condensing, but were puzzled why this condensed gas did not form into stars. Until recently, no model existed that successfully explained how this was possible.

Evan Scannapieco, a theoretical astrophysicist, has spent much of his career studying the evolution of galaxies and clusters. "There are two types of clusters: cool-core clusters and non-cool core clusters," he explains. "Non-cool core clusters haven't been around long enough to cool, whereas cool-core clusters are rapidly cooling, although by our standards they are still very hot."

Scannapieco is an assistant professor in Arizona State University's School of Earth and Space Exploration in the College of Liberal Arts and Sciences.

X-ray telescopes have revolutionized our understanding of the activity occurring within cool-core clusters. Although these clusters can contain hundreds or even thousands of galaxies, they are mostly made up of a diffuse, but very hot gas known as the intracluster medium. This intergalactic gas is only visible to X-ray telescopes, which are able to map out its temperature and structure. These observations show that the diffuse gas is rapidly cooling into the centers of cool-core clusters.

At the core of each of these clusters is a black hole, billions of times more massive than the Sun. Some of the cooling medium makes its way down to a dense disk surrounding this black hole, some of it goes into the black hole itself, and some of it is shot outward. X-ray images clearly show jet-like bursts of ejected material, which occur in regular cycles.

But why were these outbursts so regular, and why did the cooling gas never drop to colder temperatures that lead to the formation of stars? Some unknown mechanism was creating an impressive balancing act.

"It looked like the jets coming from black holes were somehow responsible for stopping the cooling," says Scannapieco, "but until now no one was able to determine exactly how."

Scannapieco and Marcus Brüggen, a professor at Jacobs University in Bremen, Germany, used the powerful supercomputers at ASU to develop their own three-dimensional simulation of the galaxy cluster surrounding one of the Universe's biggest black holes. By adapting an approach developed by Guy Dimonte at Los Alamos National Laboratory and Robert Tipton at Lawrence Livermore National Laboratory, Scannapieco and Brüggen added the component of turbulence to the simulations, which was never accounted for in the past.

That was the key ingredient.

Turbulence works in partnership with the black hole to maintain the balance. Without the turbulence, the jets coming from around black hole would grow stronger and stronger, and the gas would cool catastrophically into a swarm of new stars. When turbulence is accounted for, the black hole not only balances the cooling, but goes through regular cycles of activity.

"When you have turbulent flow, you have random motions on all scales," explains Brüggen. "Each jet of material ejected from the disk creates turbulence that mixes everything together."

Scannapieco and Brüggen's results, to be published in the journal Monthly Notices of the Royal Astronomical Society, reveal that turbulence acts to effectively mix the heated region with its surroundings so that the cool gas can't make it down to the black hole, thus preventing star formation.

Every time some cool gas reaches the black hole, it is shot out in a jet. This generates turbulence that mixes the hot gas with the cold gas. This mixture becomes so hot that it doesn't accrete onto the black hole. The jet stops and there is nothing to drive the turbulence so it fades away. At that point, the hot gas no longer mixes with the cold gas, so the center of the cluster cools, and more gas makes its way down to the black hole.

Before long, another jet forms and the gas is once again mixed together.

"We improved our simulations so that they could capture those tiny turbulent motions," explains Scannapieco. "Even though we can't see them, we can estimate what they would do. The time it takes for the turbulence to decay away is exactly the same amount of time observed between the outbursts."

Even in its native Argentina, the fire ant wins in head-to-head competition with other ant species more than three-quarters of the time, according to Agricultural Research Service (ARS) scientists

ARS scientists at the South American Biological Control Laboratory (SABCL) in Hurlingham, Argentina, have been studying how different ant species fare against the fire ant as part of an effort to learn more about the behavior of this pest—an invasive species in its non-native United States.

Fire ants often attack in swarms--not only causing painful stings to humans, but can even kill small animals. Little has been known, however, about the fire ant's competitive nature or how it interacts with other ants.

SABCL biologist Luis Calcaterra, working closely with lab director Juan Briano, has been studying interactions between the red imported fire ant, Solenopsis invicta, and other aboveground foraging ants in two habitats in northeastern Argentina—using a combination of pitfall traps and baits to study day-to-day activity in ant communities.

The pitfall trap is a 50 milliliter plastic tube buried in the ground and half-filled with soapy water. The bait is one gram of canned tuna placed on a plastic card measuring five centimeters in diameter. The trap and bait gave the scientists a way to determine ant populations at the sites, and showed the dominance of each species.

Some 28 ant species coexisted with S. invicta in an open area of forest growing along a watercourse, whereas only 10 species coexisted with S. invicta in the dry forest grassland. The researchers found that the fire ants had the highest numbers in the open forest area along the watercourse.

Prior to these studies, it was thought that the fire ant—now established throughout the Americas—was not dominant in its native land. But the studies showed that the fire ants were the most ecologically dominant, winning 78 percent of the interactions with other ants, mostly against its most frequent competitor, the South American big-headed ant, Pheidole obscurithorax, an ant of northern Argentina and Paraguay also introduced in the United States. And in battles with the invasive Argentine ant, Linepithema humile, the fire ants were even more dominant, winning out 80 percent of the time.

This study was published in Oecologia, a journal that deals with plant and animal ecology.