Most of those deaths are concentrated in sub-Saharan Africa, where an estimated 157,000 people die as a result of being exposed to such fires annually, with southeast Asia ranking second with 110,000 deaths.

"I was surprised at our estimate being so high when you consider that the exposure to fire smoke is quite intermittent for most people," said lead author Fay Johnston of the University of Tasmania.

"Even in southeast Asia and Africa, (fire) is a seasonal phenomenon. It is not year round," Johnston said at the American Association for the Advancement of Science annual meeting in Vancouver where she presented her research.

The study, which Johnston said was the first of its kind to attempt to estimate a death toll from wildfires and landscape burns, was published Saturday in the journal Environmental Health Perspectives.

Researchers looked at the number of deaths from all causes in areas that were exposed to heavy smoke and landscape fire between 1997 and 2006.

They used satellite data and chemical transport models to assess the health impacts of particulate matter smaller than 2.5 micrometers, a major byproduct of landscape fire smoke.

The number of deaths from wildfires came in far below the previously estimated global tolls for indoor air pollution at two million people per year and urban air pollution at 800,000.

However, the study authors said their findings indicated that "fire emissions are an important contributor to global mortality."

The research also suggested a significant link between climate and fire mortality.

About twice as many people died during El Nino years when the surface ocean temperature rises in the tropical eastern Pacific Ocean (averaging 532,000) as during cooler La Nina years (averaging 262,000).

Deaths could be reduced if people stopped burning tropical rainforests in order to harvest palm oil and other products, Johnston concluded.

But fires will only get more severe in the future, according to Mike Flannigan, a professor at the University of Alberta and a government scientist with Natural Resources Canada, who has done research to model how severe fires will be by the years 2081-2090.

Using a variable he called "cumulative daily severity rating," Flannigan's projections show that fire activity is "increasing over most of the globe, particularly the northern hemisphere, by a factor of two to three."

That means "significant increases" in fire activity should be expected by the end of this century as the globe gets warmer, he said.

"It is the extreme weather that drives fire activity, and if we expect more extremes in the future, which we do, then it is only going to get worse," Flannigan told reporters.

"It is getting to the point where it is beyond our control."

Already, between 350-450 million hectares burned every year in wildfires, covering an area about the size of India and costing many billions of dollars to fight and contain.

"The risk to life and infrastructure is only going to increase under climate change because of a warming climate," Flannigan said.

Current firefighting methods such as aerial suppression may have to be abandoned because they will not work against hotter, more intense fires, he said.

"It is going to be incredibly difficult in the future to manage forest fires because the intensity of fires is going to be increasing and that changes the strategy of putting fires out."

Instead, people who live near wooded areas can expect more frequent evacuations and community builders should consider fire-resistant home materials and crafting better fire guards around communities.

Governments may need to consider stronger measures in prevention, education, penalties, and restricted fire zones, he said.

"We are going to see more fire in the future, that is the bottom line. A warmer world is going to see more fire."

]]> Tue, 21 FEB 2012 08:57:32 AEST Moffett Field CA (SPX) Dec 09, 2011 - For the first time, NASA researchers have demonstrated the use of an unmanned aerial vehicle (UAV) to collect very low altitude airborne measurements of greenhouse gases at several sites in California and Nevada.

As Earth scientists strive to better understand sources and sinks of atmospheric greenhouse gases, a new aircraft capability developed at NASA Ames Research Center, Moffett Field, Calif. has the potential to provide critical measurements of carbon fluxes.

The Sensor Integrated Environmental Remote Research Aircraft (SIERRA) team recently tested several instruments including a carbon dioxide, methane, and water vapor instrument as well as a wind probe for providing instantaneous measurements of greenhouse gas fluxes. SIERRA operates as part of a network of tools to observe carbon moving on our planet.

The airborne system will assist scientists in their understanding of carbon dioxide cycling between the land, ocean and atmosphere. SIERRA complements other UAVs in the NASA science fleet by specializing in dangerous, low altitude missions that require significant payload capacity.

"Understanding the magnitude and location of carbon fluxes is important for improving our understanding of how ecosystems influence the composition of the atmosphere and the balance of climatically important gases," said Laura Iraci, the principal investigator of the NASA Ames team.

"Tower networks currently provide important information but their distribution is pre-defined. Aircraft can play an important role by enabling measurements where towers don't or cant exist, and in studying systems with features that move in time."

For example, in this desert environment, the areas of moist soil vary with season, and thus the sampling locations of interest will be different from season to season and year to year. The requirements for collecting measurements at very low altitudes (less than 100 ft) make it a dangerous proposition for pilots, so unmanned aircraft provide a great solution, Iraci added.

Matt Fladeland, research scientist from Ames, will discuss the SIERRA mission at the American Geophysical Union in San Francisco.

The SIERRA team participated in a joint science mission between Japan and the United States in June of 2011 to calibrate and validate the JAXA GOSAT satellite, as well as to explore local sources and sinks of carbon dioxide and methane.

Understanding the distribution and cycling of carbon on Earth is critical to understanding how humans affect our ecosystem and how Earth changes due to climate variations.

High frequency measurements enabled the use of the eddy covariance technique, which enables derivation of fluxes based on gas concentrations and vertical wind time series data. This technique is used in meteorology and widely used to estimate surface to atmosphere exchanges of heat, water and carbon dioxide.

The measurements demonstrated by the SIERRA team will directly support planned data products from several future NASA satellite missions including the Orbiting Carbon Observatory 2 and 3 and the Active Sensing of Carbon Dioxide Emissions over Nights, Days and Seasons (ASCENDS) mission.

]]> Tue, 21 FEB 2012 08:57:32 AEST Tel Aviv, Israel (SPX) Nov 25, 2011 - Only a few decades ago, scientists discovered the existence of "sprites" 30 to 55 miles above the surface of the Earth. They're offshoots of electric discharges caused by lightning storms, and a valuable window into the composition of our atmosphere. Now researchers at Tel Aviv University say that sprites are not a phenomenon specific to our planet.

Jupiter and Saturn experience lightning storms with flashes 1,000 or more times more powerful than those on Earth, says Ph.D. student Daria Dubrovin.

With her supervisors Prof. Colin Price of TAU's Department of Geophysics and Planetary Sciences and Prof. Yoav Yair of the Open University of Israel, and collaborators Prof. Ute Ebert and Dr. Sander Nijdam from the Eindhoven Technical University in Holland, Dubrovin has re-created these planetary atmospheres in the lab to study the presence of sprites in space.

The color of these bursts of electricity indicate what kinds of molecules are present and may explain the presence of exotic compounds, while providing insight into the conductivity of distant planets' atmospheres. This research, which was presented in October at the European Planetary Science Congress in France, could lead to a new understanding of electrical and chemical processes on Jupiter, Saturn, and Venus.

A bolt of extraterrestrial life?
Though a little-known atmospheric phenomenon, sprites are quite common on Earth, says Dubrovin. Because they occur in the mesosphere - a layer of the atmosphere that is not regularly observed by satellites and too high to be reached by atmospheric balloons - the discovery of these electric discharges, which are red in color and last only a few tens of milliseconds, was a stroke of luck.

Lightning, as a generator of organic molecules, is credited for contributing to the "primordial soup" that, according to current theories, led to the emergence of life on Earth. Researchers are keen to know more about the possibility of lightning on other planets, explains Dubrovin, not only because it impacts the technological equipment used by space programs, but because it is another clue that could indicate the presence of extraterrestrial life.

To test for the viability of extraterrestrial sprites, Dubrovin and her fellow researchers re-created the atmospheres of Jupiter, Saturn, and Venus in small containers.

A circuit that creates strong short-voltage pulses produced a discharge that mimics natural sprites. Images of these discharges, known as streamers, were taken by a fast and sensitive camera, then analyzed.

Quantifying factors such as brightness, color, size, radius, and speed could help researchers measure how powerful extraterrestrial lightning actually is, she notes. "We make sprites-in-a-bottle," says Dubrovin, smiling.

Continuing a legacy
Dubrovin believes that the team's predictions could convince scientists operating the Cassini spacecraft - now orbiting Saturn as part of an ESA/NASA mission - to point their cameras in a new direction. Currently, she says, there is a huge lightning storm occurring on Saturn producing at least 100 lightning discharges per second - a rare event that happens approximately once in a decade.

Above the lightning-producing clouds in Jupiter's and Saturn's atmosphere, Dubrovin explains, lies a layer of clouds which partly obscure the light from the flashes. If researchers were able to obtain an image of the higher-up sprites from the Cassini craft, it would enable them to gain more information about the storm below.

TAU's research is funded by the Israeli Science Foundation (ISF) and by an Ilan Ramon Scholarship and Endowment, named after the Israeli astronaut who flew on the Columbia space shuttle, through the Israeli Ministry of Science. Part of the scientific research aboard that shuttle was on sprites, notes Dubrovin, who is happy to continue the famous Israeli astronaut's legacy.

]]> Tue, 21 FEB 2012 08:57:32 AEST Washington DC (SPX) Nov 21, 2011 - Increases in air pollution and other particulate matter in the atmosphere can strongly affect cloud development in ways that reduce precipitation in dry regions or seasons. This while increasing rain, snowfall and the intensity of severe storms in wet regions or seasons, according to results of a new study.

The research provides the first clear evidence of how aerosols--soot, dust and other particulates in the atmosphere--may affect weather and climate.

The findings have important implications for the availability, management and use of water resources in regions across the United States and around the world.

"Using a 10-year dataset of atmospheric measurements, we have uncovered the long-term, net impact of aerosols on cloud height and thickness and the resulting changes in precipitation frequency and intensity," says Zhanqing Li, an atmospheric scientist at the University of Maryland and lead author of a paper reporting the results.

The paper was published in the journal Nature Geoscience.

Co-authors are Feng Niu and Yanni Ding, also of the University of Maryland; Jiwen Fan of the U.S. Department of Energy Pacific Northwest National Laboratory; Yangang Liu of the U.S. Department of Energy Brookhaven National Laboratory; and Daniel Rosenfeld of The Hebrew University of Jerusalem.

"Aerosols' effects on cloud and precipitation development are key questions for scientific community," says Chungu Lu, program director in the National Science Foundation's (NSF) Division of Atmospheric and Geospace Sciences, which funded the research.

"The question is not only important for our understanding of the effects of natural processes and human activities on climate change, but for addressing issues in air pollution, disaster relief, water resource management and human weather modification."

In addition to the scope and timeframe of the research team's observations, the scientists matched their findings with results from a cloud-resolving computer model.

"Understanding interactions among clouds, aerosols and precipitation is one of the grand challenges for climate research in the decade ahead," says Tony Busalacchi, a scientist at the University of Maryland and chair of the Joint Scientific Committee of the World Climate Research Program.

"Findings from this study are a significant advance in our understanding of such processes, with implications for both climate science and sustainable development," says Busalacchi.

"We have known for a long time that aerosols impact both the heating and phase changes [such as condensing and freezing] of clouds, and that they can either inhibit or intensify clouds and precipitation," says Russell Dickerson, an atmospheric scientist at the University of Maryland.

"What we have not been able to determine until now is the net effect," says Dickerson. "This study shows that fine particulate matter, mostly from air pollution, impedes gentle rains while exacerbating severe storms. It adds urgency to the need to control sulfur, nitrogen and hydrocarbon emissions."

According to Steve Ghan of the Pacific Northwest National Laboratory, "This work confirms what previous cloud modeling studies had suggested: that although clouds are influenced by many factors, increasing aerosols enhances the variability of precipitation, suppressing it when precipitation is light and intensifying it when it is strong.

"This complex influence is completely missing from climate models, casting doubt on their ability to simulate the response of precipitation to changes in aerosol pollution."

Aerosols are tiny solid particles or liquid particles suspended in air. They include soot, dust and sulfate particles and are what we commonly think of when we talk about air pollution.

Aerosols come, for example, from the combustion of fossil fuels, from industrial and agricultural processes and from the accidental or deliberate burning of fields and forests.

They can be hazardous to human health and the environment.

Aerosol particles also affect the Earth's surface temperature by reflecting light back into space.

The variable cooling and heating that results is, in part, how aerosols modify the stability that dictates atmospheric vertical motion and cloud formation.

Aerosols also affect cloud microphysics because they serve as nuclei around which water droplets or ice particles form.

Both processes can affect cloud properties and rainfall. Different processes may work in harmony or offset each other, leading to complex yet inconclusive interpretations, scientists say, of their long-term net effect.

Researchers agree that greenhouse gases and aerosol particles are two major agents dictating climate change.

The mechanisms of climate warming effects of increased greenhouse gases are clear: they trap solar energy absorbed at the Earth's surface and prevent it from being radiated as heat back into space.

The climate effects of increased aerosols are much less certain.

"This study demonstrates the importance and value of keeping a long record of continuous and comprehensive measurements to identify and quantify the important roles of aerosols in climate processes," says Steve Schwartz, a scientist at Brookhaven National Laboratory.

"While the mechanisms for some of these effects remain uncertain, the well-defined relationships discovered demonstrate their significance," says Schwartz. "Controlling for these processes in models remains a future challenge, but this study clearly points to important directions."

"The findings from ground measurements of long-term effects are consistent with the global effects revealed from satellite measurements reported in our separate study," says Li.

"They attest to the needs of tackling the climate and environmental changes that matter so much to our daily lives."

]]> Tue, 21 FEB 2012 08:57:32 AEST Freiburg, Germany (SPX) Nov 09, 2011 - The soot particle filters found on diesel vehicles are designed to ensure that no harmful particles make their way through the exhaust pipe. Often, though, the exhaust from newer-model engines is not hot enough to free the filters from soot particles on a regular basis. A new method removes impurities even at low exhaust temperatures.

Long gone are the days when trucks spewed black clouds of exhaust into the air: Nowadays, there are filters in place that capture the largest of these soot particles. After a time, if too much soot accumulates in the filter, the soot is burned off and the filter is regenerated.

The problem: Soot particles only burn above temperatures of 500 to 600 degrees Celsius. Yet the temperature of truck exhaust is increasingly dropping as part of the effort to minimize emissions of nitric oxides harmful to the environment.

There exist two approaches to removing soot from the filter: the first involves an oxidation catalytic converter that converts nitrogen monoxide in the exhaust into nitrogen dioxide. If nitrogen dioxide is passed through the filter, the soot burns at lower temperatures.

In some engine operating states - such as when the engine is still cold - this regeneration method does not suffice: In these cases, liquid fuel is added, that combusts with residual oxygen in the exhaust to heat the exhaust and filter.

This cleansing method only works at exhaust temperatures in excess of 230 degrees Celsius, however. At lower temperatures, the fuel-exhaust mixture fails to ignite, damaging the catalytic converter. The problem: Exhaust from newer-model truck engines is only 160 to 180 degrees Celsius.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany, have come up with a method that reliably regenerates filters even at exhaust temperatures as low as 140 degrees.

"We add a synthesis gas consisting of carbon monoxide and hydrogen to the exhaust," explains Dr. Thomas Aicher, group manager at ISE.

"We introduce this gas mixture at the oxidation catalytic converter - lowering the ignition temperature to 140 degrees Celsius and freeing the filter from soot even at these low exhaust temperatures."

But where does this synthesis gas come from? "We have two ways to generate this gas: One is to heat diesel fuel in the absence of air. This produces hydrogen and carbon. Then, the carbon is burned with the exhaust, creating carbon monoxide. Experts refer to this process as pyrolysis. The other way is to oxidize diesel with a very small amount of air so that the diesel combusts only partially.

This is known as partial oxidation," explains Robert Szolak, a scientist at ISE. Researchers have already built and successfully tested prototypes for both approaches. The experts have now partnered with an industrial partner to investigate partial oxidation in greater detail.

Research News October 2011 [ PDF 0.37MB ]

]]> Tue, 21 FEB 2012 08:57:32 AEST Hampton VA (SPX) Nov 03, 2011 - On a bluff overlooking the Atlantic, Grady Koch spent a month watching ocean winds. He beamed a laser over the sea, day after day, measuring conditions offshore using an instrument called Doppler Aerosol Wind (DAWN) lidar. What Koch learns from the experiment will be used by scientists to advance weather forecasting technology - and also by a consortium hoping to develop a wind farm in the very spot where the wind data is being taken.

"It's been going well," said Koch, a scientist at NASA's Langley Research Center in Hampton, Va.

"It works. We're showing that we can measure wind at different heights. One issue we've been working is, how far can we see? We've been able to see pretty well out to 12 kilometers (7.5 miles)."

The wind farm is proposed by the Virginia Coastal Energy Research Consortium, a partnership of universities, state and local governments, and industry. The Virginia legislature formed the consortium in 2007 to develop coastal energy technologies.

Alternative Energy
A wind farm would provide Virginia with about 10 percent of its power demand, said George Hagerman, a scientist at Virginia Tech, a consortium partner.

"We're at a point now where offshore wind is not just an academic exercise," he said. I don't think it's a question of 'if.' It's a question of when."

The consortium, Hagerman said, is working with private and government agencies to ensure the potential wind farm is placed in an area where it does not interfere with shipping routes or military exercises, which are common in the waters off Virginia Beach.

The location under study is about 15 miles off the Atlantic coast in Virginia Beach, Va. and covers about 240 square miles. Companies wishing to place wind-powered energy generators in the area would have to sign leases with the federal government, which controls the waters, Hagerman said.

A huge requirement for persuading industry to invest is providing them with reliable data about wind speed and direction.

That's where NASA Langley comes in.

The DAWN laser used by Grady Koch is extremely powerful, and capable of compiling three-dimensional wind profiles. "It's much stronger than anything you can buy on the commercial market," Koch said.

DAWN is the product of three decades of development for use in weather forecasting.

Ultimate Goal
Last year, for example, DAWN was part of a research campaign called the Genesis and Rapid Intensification Process (GRIP) mission. The campaign was conducted to better understand how tropical storms form and develop into hurricanes.

The laser function of DAWN measures wind speed and direction by tracking dust and other particles blowing in the wind. The particles, in a sense, illuminate the wind.

For the current project, DAWN was fitted to a large trailer and towed from Langley to the experiment site. It's a stone's throw from the ocean at the Joint Expeditionary Base Little Creek-Fort Story, an Army/Navy installation at Cape Henry, where the Atlantic meets the Chesapeake Bay.

For NASA, the experiment will add much-needed marine wind data to an existing 30-year dataset about wind. That information will be used to improve the capabilities of instruments like DAWN.

The hope is to provide new data for meteorologists so they can make better forecasts about hurricane intensity, track, and landfall. Eventually, scientists hope, a DAWN-like instrument will be launched into space to provide continuous global coverage.

Said Koch of the wind-profiling project: "We're proving a concept."

]]> Tue, 21 FEB 2012 08:57:32 AEST Beijing (AFP) Oct 31, 2011 - Air pollution in Beijing reached "hazardous" levels on Monday, the US embassy said, as thick smog blanketed the city for the third day running, forcing the closure of highways and cancellation of flights.

The Chinese capital is one of the most polluted cities in the world, mainly due to its growing energy consumption -- much of which is still fuelled by coal-fired power stations -- and the high number of cars on the road.

A "hazardous" rating by the US embassy, whose evaluation of the city's air quality often differs markedly from the official Chinese rating, is the worst on a six-point scale and indicates the whole population is likely to be affected.

The embassy has rated Beijing's air quality as hazardous on several occasions this month. On October 9, the reading was listed as "beyond index", meaning it went above measurable levels.

By contrast, China's environment ministry said Beijing's air was just "slightly polluted" on Sunday -- the most recent data available -- sparking a debate in China's state-run media and on the Internet.

Even the usually nationalist Global Times newspaper on Monday demanded an explanation for the disparity, urging the government to "be cooperative in avoiding confusing information" about air pollution.

"Figures by some local governments show the air pollution index is dropping in some cities, such as Beijing... But some Beijing citizens complain the figures do not match their experience," it said in an editorial.

Residents of the capital expressed their fears over the effects on their health on Sina Weibo, a Chinese microblogging site similar to Twitter, with some reporting breathing difficulties and dizziness.

"The pollution reading was again hazardous this morning. We are inhaling poisons," wrote a blogger under the name Xuemanzi.

In April, Beijing launched a five-year action plan to improve the environment by phasing out coal-fired boilers, saying it wanted excellent or good air conditions for 80 percent of the days in the year by 2015.

Authorities said they would refurbish highly polluting coal-fired boilers and stoves in six Beijing districts with equipment that uses clean energy, and also try to phase out 400,000 old, polluting vehicles before the end of 2015.

Beijing's weather bureau issued three heavy fog alerts on Sunday. Six highways closed and over 200 flights were delayed or cancelled as a result, Chinese media reports said.

]]> Tue, 21 FEB 2012 08:57:32 AEST Livermore, CA (SPX) Nov 01, 2011 - Climate models have a hard time representing clouds accurately because they lack the spatial resolution necessary to accurately simulate the billowy air masses.

But Livermore scientists and international collaborators have developed a new tool that will help scientists better represent the clouds observed in the sky in climate models.

Traditionally, observations from satellites infer the properties of clouds from the radiation field (reflection of sunlight back into space, or thermal emission of the planet). However, to accurately utilize satellite data in climate model assessment, a tool is required that allows an apples-to-apples comparison between the clouds simulated in a climate model and the cloud properties retrieved from satellites.

"The models are becoming more interactive and are taking into account the radiation data from the satellite observations and is an important part of the process of making better climate models," said the Lab's Stephen Klein, who along with LLNL's Yuying Zhang and other collaborators have developed the Cloud-Feedback-Model Intercomparison Project Observation Simulator Package (COSP).

"The models have been improving and refining their representations of clouds and COSP will play an important role in furthering this improvement," Klein said.

Climate models struggle to represent clouds accurately because the models lack the spatial resolution to fully represent clouds. Global climate models typically have a 100-kilometer resolution while meteorological models have a 20-kilometer range. However, to accurately represent clouds as seen in satellite measurements, the scale would need to be from the 500-meter resolution to 1-kilometer range.

"But those small scales are not practical for weather or global climate models," Klein said. "Our tool will better connect with what the satellites observe - how many clouds, their levels and their reflectivity."

The COSP is now used worldwide by most of the major models for climate and weather prediction, and it will play an important role in the evaluation of models that will be reviewed by the next report of the Intergovernmental Panel on Climate Change, Klein said.

The COSP allows for a meaningful comparison between model-simulated clouds and corresponding satellite observations. In other words, what would a satellite see if the atmosphere had the clouds of a climate model?

"COSP is an important and necessary development because modeled clouds cannot be directly compared with observational data; the model representation of clouds is not directly equivalent to what satellites are able to see," Klein explained.

"The COSP eliminates significant ambiguities in the direct comparison of model simulations with satellite retrievals."

COSP includes a down-scaler that allows for large-scale climate models to estimate the clouds at the satellite-scale. The tool also allows modelers to diagnose how well models are able to simulate clouds as well as how climate change alters clouds.

The tool already has revealed climate model limitations such as too many optically thick clouds, too few mid-level clouds and an overestimate of the frequency of precipitation.

Additionally, COSP has shown that climate change leads to an increase in optical thickness and increases the altitude of high clouds and decreases the amount of low and mid-level clouds.

Other collaborators include: the UK's Hadley Centre, Universite Pierre et Marie Curie; University of Washington; Monash University, University of Colorado; and the National Oceanic and Atmospheric Administration/Earth System Research Laboratory.

"COSP: Satellite simulation software for model assessment," Bulletin of the American Meteorological Society

"Increase in atmospheric moisture tied to human activities," LLNL news release, Sept. 18, 2007

"Identification of Human-Induced Changes in Atmospheric Moisture Content," Proceedings of the National Academy of Sciences, Sept. 25, 2007. LLNL's Program for Climate Model Diagnosis and Intercomparison

]]> Tue, 21 FEB 2012 08:57:32 AEST Munich, Germany (SPX) Oct 18, 2011 - The anaerobic oxidation of ammonia (anammox) is an important pathway in the nitrogen cycle that was only discovered in the 1980s. Currently, scientists estimate that about 50 percent of the nitrogen in the atmosphere is forged by this process.

A group of specialized bacteria perform the anammox reaction, but so far scientists have been in the dark about how these bacteria could convert ammonia to nitrogen in the complete absence of oxygen. Now, 25 years after its discovery, they finally solved the molecular mechanism of anammox.

Anammox bacteria are very unusual because they contain an organelle which is a typical eukaryotic feature. Inside this organelle, known as the "anammoxosome", the bacteria perform the anammox reaction. The membrane of the anammoxosome presumably protects the cells from highly reactive intermediates of the anammox reaction.

These intermediates could be hydrazine and hydroxylamine, as microbiologists proposed many years ago. This was very exciting news because the turnover of hydrazine, a very powerful reductant also used as rocket fuel, had never been shown in biology. However, these early experiments were provisional and many open questions remained.

To finally unravel the pathway experimentally was a very difficult enterprise. Marc Strous from the Max Planck Institute in Bremen says: "The anammox organisms are difficult to cultivate because they divide only once every two weeks.

Therefore we had to develop cultivation approaches suitable for such low growth rates. Even after 20 years of trials, we can still only grow the organisms in bioreactors and not in pure culture."

In the present study, the researchers make use of the latest innovation in bioreactor technology for anammox cultivation: the membrane bioreactor. In such bioreactors the anammox organisms grow as suspended cells rather than in biofilms on surfaces, and relatively few contaminating organisms are present.

The study makes use of protein purification and proteins cannot be effectively purified from biofilms because of the large amount of slime associated with these biofilms.

Another important key to the metabolism was the availability of the genome sequence of one of the best known anammox bacteria, Kuenenia stuttgartiensis.

With the knowledge of the genome, the authors knew which proteins could be important. Based on the genome sequence, they could predict that nitric oxide, not hydroxylamine, might be the precursor for hydrazine.

With a set of state-of-the art molecular methods the scientists could thus completely unravel the anammox pathway, and unequivocally establish the role of hydrazine and nitric oxide (NO) as intermediates.

"With this significant advance we can finally understand how the nitrogen in the air we breathe is created: from rocket fuel and nitric oxide!" concludes Marc Strous. With the establishment of the prominent role of nitric oxide in both anammox and denitrification, the research also opens a new window on the evolution of the biological nitrogen cycle in the Earth's distant past.

Marc Strous explains: "In the early days in Earth's history, the nitric oxide accumulated in the atmosphere by vulcanic activity, was presumably the first "deep electron sink" on earth and may so have enabled the evolution of both microbial metabolic pathways anammox and denitrification."

]]> Tue, 21 FEB 2012 08:57:32 AEST Washington DC (SPX) Oct 11, 2011 - Few people have ever claimed to see three rainbows arcing through the sky at once. In fact, scientific reports of these phenomena, called tertiary rainbows, were so rare - only five in 250 years - that until now many scientists believed sightings were as fanciful as Leprechaun's gold at a rainbow's end.

These legendary optical rarities, caused by three reflections of each light ray within a raindrop, have finally been confirmed, thanks to photographic perseverance and a new meteorological model that provides the scientific underpinnings to find them. The work is described in a series of papers in a special issue published this week in the Optical Society's (OSA) journal Applied Optics.

In addition to the confirmed photo of a tertiary rainbow, the optical treasure hunt went one step further, as revealed in another photo that shows the shimmering trace of a fourth (quaternary) rainbow.

Raymond Lee, a professor of meteorology at the U.S. Naval Academy, did not snap those pictures, but he did make them possible. One year ago, Lee predicted how tertiary rainbows might appear and challenged rainbow chasers to find them.

Although staggeringly rare, tertiary and quaternary rainbows are natural products of the combination of refraction, dispersion, and reflection inside raindrops. These are the same processes that create all rainbows, yet they are taken to their most extreme to produce these higher order variants.

Refraction is when sunlight bends as it moves from air into water and vice versa. (Such bending makes oars look bent when partially submerged.) Water droplets bend each of the colors in sunlight by a slightly different angle. This is called dispersion, and it separates the colors to create a rainbow.

Most of that multicolored light passes through the other side of the raindrop, but some is reflected. The raindrop's spherical curves concentrate those reflections at 138 degrees from the Sun. This concentrated light is bright enough to create a visible primary rainbow.

A double rainbow occurs because not all that light exits the raindrop. Some is reflected back into the raindrop and goes through the whole process again. Although this light is dimmer, sometimes it is bright enough to produce a secondary rainbow just outside the first.

A third series of reflections creates a tertiary rainbow. It is even dimmer than the secondary rainbow, and much harder to find because instead of forming away from the Sun, a tertiary rainbow forms around the Sun. To see it, observers have to look into the Sun's glare.

This may be why only five scientifically knowledgeable observers had described tertiary rainbows during the past 250 years.

Lee reviewed each description. He eliminated one questionable account and found common elements in the others. All described tertiary rainbows that appeared for a few seconds against a dark background of clouds about 40 degrees from a brightly shining sun.

Along with colleague Philip Laven, Lee used a mathematical model to predict what conditions might produce visible tertiaries. First, they needed dark thunderclouds and either a heavy downpour or a rainstorm with nearly uniformly sized droplets.

Under these conditions, if the Sun broke through the clouds, it could project a tertiary rainbow against the dark clouds nearby. The contrasting colors would make the dim tertiary visible.

When Lee presented his findings at last year's International Conference on Atmospheric Optics, it sparked heated discussion. Some scientists insisted that past descriptions were wrong and that tertiaries were too dim to see in the Sun's glare.

One attendee, Elmar Schmidt, an astronomer at Germany's SRH University of Applied Sciences in Heidelberg and a rainbow chaser, took the guidelines as a challenge. He alerted likeminded amateurs. Since then, Michael Grossman and Michael Theusner have snapped photos of tertiary rainbows.

One photo even shows a quaternary rainbow, and both images, which underwent only minimal image processing to improve the contrast under these challenging photographic conditions, appear in the same Applied Optics special issue as Lee and Laven's paper.

The day Grossman photographed the tertiary rainbow, he first recalled seeing a double rainbow. When the rain intensified, he knew he had to turn toward the Sun. "It is really exaggerated to say that I saw it, but there seemed to be something," he says. The pictures he snapped in the rain were the first to show a tertiary rainbow.

Of the noteworthy discovery, "it was as exciting as finding a new species," Lee says.

Papers: Visibility of natural tertiary rainbows, Raymond L. Lee, Jr. and Philip Laven, Applied Optics, Vol. 50, Issue 28, pp. F152-F161 (2011) This research received support from National Science Foundation grants AGS-0914535 and AGS-0540896. Photographic evidence for the third-order rainbow, Michael Grossmann, Elmar Schmidt, and Alexander Haussmann, Applied Optics, Vol. 50, Issue 28, pp. F134-F141 (2011). Photographic observation of a natural fourth-order rainbow, Michael Theusner, Applied Optics, Vol. 50, Issue 28, pp. F129-F133 (2011)

]]> Tue, 21 FEB 2012 08:57:32 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