SALT LAKE CITY – More than 150 years after a small Eurasian tree named tamarisk or saltcedar started taking over river banks throughout the U.S. Southwest, saltcedar leaf beetles were unleashed to defoliate the exotic invader.

Now, University of Utah scientists say their new study shows it is feasible to use satellite data to monitor the extent of the beetle’s attack on tamarisk, and whether use of the beetles may backfire with unintended environmental consequences.

“We don’t have any idea of the long-term impacts of using the beetles; their release may have unexpected repercussions,” says Philip Dennison, an assistant professor of geography and first author of the study scheduled for online publication later this month in the journal Remote Sensing of Environment.

“The impact of this defoliation is largely unknown,” says study co-author Kevin Hultine, a research assistant professor of biology at the University of Utah. “The net impact of controlling tamarisk could be positive or negative.”

“We would like on-the-ground scientists and managers to understand and think about the long-term impact – what are these riparian [riverbank] areas going to look like 15 years from now, and how can we can maintain ecosystems” as well as water flows for farms, cities and river recreation, Hultine says.

Dennison and Hultine conducted the study with Jim Ehleringer, a distinguished professor of biology at the University of Utah; physical scientist Pamela Nagler, of the U.S. Geological Survey in Tucson, Ariz.; and Edward Glenn, a University of Arizona environmental scientist.

A Shady Invader from Eurasia

Anyone who has rafted Southwestern rivers like the Green and Colorado knows about the shady thickets of tamarisk that line the riverbanks. The trees can grow up to 30 feet tall. There are about 10 species of tamarisk.

This 2007 infrared image from the ASTER instrument on NASA’s Terra satellite shows the effects of saltcedar leaf beetles that were released to defoliate tamarisk. An alfalfa field along the Colorado River remains vegetated and thus is bright red. But the wet “bottom” area along the Dolores River (lower right) appears much darker than in the 2006 image because the beetles have eaten tamarisk leaves. Remaining areas of bright red within the “bottom” area are due to willow and cottonwood trees. University of Utah researchers propose using satellites to monitor tamarisk defoliation by beetles in remote areas of the Southwest.

Credit: Phil Dennison, University of Utah, from NASA data.

The U.S. Animal and Plant Health Inspection Service (APHIS) says saltcedar or tamarisk is “a highly invasive, exotic weed” in the form of “a large shrub or small tree that was introduced to North America from Asia in the early 1800s. The plant has been used for windbreaks, ornamentals, and erosion control. By 1850, saltcedar had infested river systems and drainages in the Southwest, often displacing native vegetation.”

“By 1938, infestations were found from Florida to California and as far north as Idaho,” according to APHIS. “Saltcedar continues to spread rapidly and currently infests water drainages and areas throughout the United States.”

Tamarisk dominates riverbank habitats, limiting camping areas for river runners, reducing diversity and providing poor habitat for some species of wildlife. Tamarisk also raises the risk of fires that destroy cottonwoods and other native plants but not tamarisk, which re-sprouts from roots. And tamarisk forms a dense canopy, also helping wipe out competing plants. Finally, tamarisk has a bad rap as a water-sucking wastrel that dries springs, lowers water tables and reduces stream flows, even impairing boating.

Dennison and Hultine say recent research indicates tamarisk’s thirst is overstated.

“Some of the earliest research on tamarisk water use suggested tamarisk uses dramatically more water than other tree species,” Hultine says. “So a lot of estimates on water loss over entire river reaches are based on information that now has been discredited in the scientific literature.”

Hultine believes that unless aggressive programs to restore defoliated areas are implemented, tamarisk will be replaced by other invaders – Russian knapweed, Russian olive and pepperweed – that may use more water than tamarisk. Eradicating tamarisk with beetles also may reduce bird habitat, he adds.

Monitoring the Attack of the Tamarisk-Munching Beetles

The saltcedar leaf beetle, Diorhabda elongata, was brought to the U.S. from Kazakhstan. After an environmental assessment, APHIS approved them for tamarisk control.

Dennison says thousands of the beetles first were released in Utah during summer 2004, then again in summer 2005 and 2006 at locations along the Colorado River near Moab. Widespread defoliation of tamarisk in the area was noted during summer 2007.

Because long stretches of rivers in the Colorado River Basin are remote, Dennison and colleagues decided to test the feasibility of using satellite images to detect tamarisk leaf loss due to the spread of the saltcedar leaf beetles.

This 2006 infrared image of the confluence of the Colorado and Dolores rivers in Utah was taken by the ASTER instrument on NASA’s Terra satellite. The Colorado flows from north to south and the Dolores enters the image from the east. Vegetation appears bright red, including an alfalfa field along the Colorado and a wet “bottom” area along the Dolores that has extensive tamarisk, an invasive tree from Eurasia.

Credit: Phil Dennison, University of Utah, from NASA data.

They mapped 56 accessible areas already defoliated by tamarisk, and studied if the defoliation could be detected using two instruments on Terra, one of the National Aeronautics and Space Administration’s Earth-observing satellites.

Both instruments make images using red and near-infrared light. Plant pigments absorb red from sunlight and reflect near-infrared. In near-infrared images, tamarisk-covered areas appear red. Defoliated areas appear brown or black because there are no leaves to absorb red light and reflect near-infrared light. The two instruments are:

• ASTER, the Advanced Spaceborne Thermal Emission and Reflection Radiometer, obtains relatively high-resolution images, with each pixel covering an area about 50 feet long by 50 feet wide. It can detect big changes like tamarisk defoliation on an even smaller scale. It only obtains one to three images of a given area every summer.
• MODIS, the Moderate Resolution Imaging Spectroradiometer, which can detect less detail – a pixel measures about 820 feet by 820 feet. But it can see where large swaths of tamarisk have been defoliated, Dennison says. MODIS makes daily images.

Dennison says the infrequent, higher-resolution ASTER images allow researchers to map defoliated areas, while the frequent, lower-resolution MODIS images help them detect changes in vegetation over time.

The area studied included four sites along the Colorado River northeast of Moab, and a fifth site along the tributary Dolores River at the Entrada Field Station operated by the University of Utah for education and research. The five sites covered 589 acres, and within them, researchers mapped 56 polygon-shaped areas totaling 57 acres where tamarisk had been defoliated by the beetles.

ASTER measured what is known as NVDI – the normalized difference vegetation index, which is the difference between red light absorbed by plants and near-infrared light reflected by them. The index is high when plants are present, low when they are absent.

Those satellite measurements showed minor changes in vegetation at the test sites from 2005 to 2006, but a large change between 2006 and 2007 – indicating extensive defoliation of tamarisk, even though the defoliated plants regrow within about six weeks.

The satellite’s MODIS instrument used another vegetation index that also revealed widespread tamarisk defoliation at the five sites in July 2007.

While some tamarisk has died in Nevada where the beetles first were established, “we don’t understand whether repeated defoliation eventually will kill most of the trees, or will they reach some point where they’ll just have less leaf area over the entire year,” Hultine says.

The researchers also used the satellite to estimate “evapotranspiration” – the evaporation of water from soil and the transpiration or use of water by plants – to learn more about how defoliation of tamarisk affects water use. For comparison, Hultine measured sap flow through trees, which reflects how much water is used by the trees.

Satellite estimates of tamarisk water use declined modestly as the plants were defoliated, Dennison says. The findings also were consistent with earlier research indicating tamarisk is less of a water hog than previously thought.

Dennison says he and his colleagues did the study to test the feasibility of using satellites to monitor tamarisk defoliation on an ongoing basis. That, he says, could be done by federal agencies such as the Bureau of Land Management, Bureau of Reclamation and U.S. Geological Survey.

Source: University of Utah

Scientists identified seven new species of bamboo coral discovered on a NOAA-funded mission in the deep waters of the Papahānaumokuākea Marine National Monument. Six of these species may represent entirely new genera, a remarkable feat given the broad classification a genus represents. A genus is a major category in the classification of organisms, ranking above a species and below a family. Scientists expect to identify more new species as analysis of samples continues.

“These discoveries are important, because deep-sea corals support diverse seafloor ecosystems and also because these corals may be among the first marine organisms to be affected by ocean acidification,” said Richard Spinrad, Ph.D., NOAA’s assistant administrator for Oceanic and Atmospheric Research. Ocean acidification is a change in ocean chemistry due to excess carbon dioxide. Researchers have seen adverse changes in marine life with calcium-carbonate shells, such as corals, because of acidified ocean water.

“Deep-sea bamboo corals also produce growth rings much as trees do, and can provide a much-needed view of how deep ocean conditions change through time,” said Spinrad.

Rob Dunbar, a Stanford University scientist, was studying long-term climate data by examining long-lived corals. “We found live, 4,000-year-old corals in the Monument – meaning 4,000 years worth of information about what has been going on in the deep ocean interior.”

“Studying these corals can help us understand how they survive for such long periods of time as well as how they may respond to climate change in the future,” said Dunbar.

Among the other findings were a five-foot tall yellow bamboo coral tree that had never been described before, new beds of living deepwater coral and sponges, and a giant sponge scientists dubbed the “cauldron sponge,” approximately three feet tall and three feet across. Scientists collected two other sponges which have not yet been analyzed but may represent new species or genera as well.

The mission also discovered a “coral graveyard” covering about 10,000 square feet on a seamount’s summit, more than 2,000 feet deep. Scientists estimated the death of the community occurred several thousand to potentially more than a million years ago, but did not know why the community died. The species of coral had never been recorded in Hawaii before, according a Smithsonian Institution coral expert they consulted.

Finding new species was not an express purpose of the research mission, but Dunbar and Christopher Kelley, a scientist with the University of Hawaii, both collected specimens that looked unusual. Kelley’s objective was to locate and predict locations of high density deep-sea coral beds in the Monument. NOAA scientist Frank Parrish also led a portion of the mission, focusing on growth rates of deep-sea corals.

The three-week research mission ended in November 2007, but analysis of specimens is ongoing. “The potential for more discoveries is high, but these deep-sea corals are not protected everywhere as they are here, and can easily be destroyed,” said Kelley.

The Papahānaumokuākea Marine National Monument has more deep water than any other U.S. protected area, with more than 98 percent below SCUBA-diving depths and only accessible to submersibles. The Hawaii Undersea Research Laboratory, sponsored by NOAA and the University of Hawaii, piloted the Pisces V submersible from a research vessel to the discovery sites, between 3300 and 4200 feet deep.

Source: NOAA Headquarters

The water levels in the Dead Sea – the deepest point on Earth – are dropping at an alarming rate with serious environmental consequences, according to Shahrazad Abu Ghazleh and colleagues from the University of Technology in Darmstadt, Germany. The projected Dead Sea-Red Sea or Mediterranean-Dead Sea Channels therefore need a significant carrying capacity to re-fill the Dead Sea to its former level, in order to sustainably generate electricity and produce freshwater by desalinization. The study (1), published online this week in Springer’s journal, Naturwissenschaften, also shows that the drop in water levels is not the result of climate change; rather it is due to ever-increasing human water consumption in the area.

Normally, the water levels of closed lakes such as the Dead Sea reflect climatic conditions – they are the result of the balance between water running into the lake from the tributary area and direct precipita-tion, minus water evaporation. In the case of the Dead Sea, the change in water level is due to intensive human water consumption from the Jordan and Yarmouk Rivers for irrigation, as well as the use of Dead Sea water for the potash industry by both Israel and Jordan. Over the last 30 years, this water consumption has caused an accelerated decrease in water level (0.7 m/a), volume (0.47 km³/a) and surface area (4 km² /a), according to this study.

Abu Ghazleh and colleagues developed a model of the surface area and water volume of the Dead Sea and found that the lake has lost 14 km3 of water in the last 30 years. The receding water has left leveled sections on the lake’s sides – erosional terraces – which the authors recorded precisely for the first time using Differential Global Positioning System (DGPS) field surveys. They were able to date the terraces to specific years.

The authors point out that this rapid drop in the level of the Dead Sea has a number of detrimental con-sequences, including higher pumping costs for the factories using the Dead Sea to extract potash, salt and magnesium; an accelerated outflow of fresh water from surrounding underground water aquifers; receding shorelines making it difficult for tourists to access the water for medicinal purposes; and the creation of a treacherous landscape of sinkholes and mud as a result of the dissolution of buried salt which causes severe damage to roads and civil engineering structures.

To address the mounting stress on water resources in the Dead Sea basin and the environmental ha-zards caused by its lowering, the authors suggest that the diversion of Jordan water to the Mediterra-nean coast could be replaced by desalinization of seawater, causing the recession of the Dead Sea to be considerably slowed, and buying time to consider the long-term alternatives such as the Red Sea-Dead Sea Channel or the Mediterranean-Dead Sea Channel.

The authors conclude that either of these channels will require a carrying capacity of more than 0.9 km3 per year to slowly fill the lake back to its levels of 30 years ago and to ensure its long-term sustai-nability for energy production and desalinization to fresh water. Such a channel will also maintain tour-ism and potash industry on both sides of the Dead Sea.

Source: Springer

Current tests are not effective for assessing patients’ physical and mental health. A commonly used questionnaire that measures quality of life is not sensitive enough to pick up mental and physical problems experienced by patients with autosomal dominant polycystic kidney disease (ADPKD), according to a study appearing in an upcoming issue of the Clinical Journal of the American Society Nephrology (CJASN). Findings indicate that patients with this condition, (the most common form of hereditary kidney disease) need better tests to adequately measure quality of life.

ADPKD, characterized by a slow expansion of the kidneys and liver due to the growth of cysts, causes pain, shortness of breath, fatigue, and decreased appetite. Researchers and physicians do not yet have a clear measure of the impact of ADPKD on patients’ quality of life.

A team of investigators recently evaluated the effectiveness of a quality of life questionnaire for assessing the well being of ADPKD patients. The SF-36 questionnaire is one of the most commonly used questionnaires in medicine. The test addresses the physical and mental health of patients with chronic illness and is standardized for the general US population.

Arlene Chapman, MD, of the Emory University School of Medicine in Atlanta, Georgia, and her colleagues analyzed SF-36 test results of 152 adults with ADPKD and compared them with results from people in the general population. Because ADPKD is associated with significant physical ailments, the researchers hypothesized that ADPKD patients would report lower physical and mental quality of life scores on the SF-36 questionnaire than the general population.

The researchers found that there were links between certain patient characteristics and physical scores on the SF-36 test. Age, body mass index, pulse pressure, pain medication use, and education level were found to play a role in patients’ physical well being. However, ADPKD patients had physical and mental scores that were similar to those of the general population.

“The results of this study may reflect that ADPKD patients are generally very motivated to cope with their disease. However, these same results raise the question of whether the SF-36 is an appropriate tool to evaluate quality of life in pre-ESRD chronic kidney disease populations such as those with ADPKD,” the authors wrote.

According to Dr. Chapman, the SF-36 questionnaire is relatively insensitive in determining both mental and physical well being in ADPKD individuals and “more precise validated questionnaires are needed in ADPKD patients prior to initiation of renal replacement therapy to determine the potential benefits of novel therapeutic interventions.”

Source: American Society of Nephrology

The anthropology world is all abuzz with a discovery in Africa that’s knocking scientists off their feet.

It’s the finding of 1.5 million-year-old fossilized human footprints in Kenya at Rutgers University’s Koobi Fora Field School.

Researchers say the ancient footprints show that some of the earliest humans walked just like we do today and also had anatomically modern feet.

The area around the human footprints was also littered with a range of animal prints, all discovered within two 1.5 million-year-old sedimentary layers near Ileret in northern Kenya.

Three footprint trails were found in the upper sediment layer. Two of them had two prints each, while the other had seven prints and numerous isolated prints. Perfectly preserved 15 feet below were one trail of two prints and a single isolated smaller print, possibly that of a child.

The discovery is detailed in this month’s issue of the journal Science.

What makes these footprints decidely human? Researchers say the big toe is parallel to the other toes, whereas in apes, it is separated for better grasping in the trees. What’s more, the footprints show a human-like arch and short toes, typically associated with walking upright. Other clues found to be within the range of modern humans were the size, spacing and depth of the impressions which provided estimates of weight, stride and gait.

The authors say the size of the footprints and their modern anatomical characteristics point to the hominid Homo ergaster, the name by which early Homo erectus is more generally known. This was the first hominid to have had the same body proportions (longer legs and shorter arms) as modern Homo sapiens. Other H. ergaster or H. erectus remains have been found in Tanzania, Ethiopia, Kenya and South Africa, at dates consistent with the Ileret footprints.

Enhanced geothermal energy using modern research methods

Potsdam, 26.02.2009 – Geothermal energy is increasingly contributing to the power supply world wide. Iceland is world-leader in expanding development of geothermal utilization: in recent years the annual power supply here doubled to more than 500 MW alone in the supply of electricity. And also in Germany, a dynamic development is to be seen: over 100 MW of heat are currently being provided through geothermal energy.

Alone in the region of Travale, in the pioneering country Italy, a team of european scientists have localizied geothermal reservoirs, holding a potential comparable to the effectiveness of 1.000 wind power plants. This is one of the results presented at the international final conference of the project „I-GET” (Integrated Geophysical Exploration Technologies for deep fractured geothermal systems) in Potsdam. The aim of this European Union project, in which seven european nations participated, was the development of cutting-edge geophysical methods with which potential geothermal reservoirs can be safely explored and directly tapped.

„The new methods deliver important decision-support for the selection of sites for future geothermal projects. With this we can considerably reduce the risk of expensive misdrills” explains Dr. Ernst Huenges, Head of Geothermal Research at the host institute GFZ – German Research Centre for Geosciences.

The newly developed approaches have been tested at four European geothermal locations with different geological and thermo¬dynamic conditions: high-temperature reservoirs have been examined in Travale/Italien (metamorphic rocks) and in Hengill/Island (volcanic rocks), two deposits with medium-temperature in deep sediment rocks are Groß-Schönebeck/Germany and Skierniewice/Poland. The methodology is based on the measurement of seismic velocities and electrical conductivity in the underground which deliver information on the rock-physical characteristics at depth. Different methods have, hereby, been combined, in addition to borehole measurements and rock-analysis.

I-GET experiments have been carried out using a case study in the surrounding of the GFZ research borehole at Groß Schönebeck, nordwest of Berlin. And here, extensive pre-knowledge from experimental investigations in the in situ geothermal-laboratory in Groß Schönebeck is already available. The geological conditions prevailing in the North German Basin are representative for further parts of central Europe, and thus the research results are also of high interest beyond Germany’s borders.

The GFZ, member of the Helmholtz-Association of German Research Centres, had the leading role in I-GET and was able to contribute with is acquired knowledge in the field of low-temperature geothermal reservoirs.

The results of I-GET emanate worldwide: experts from Indonesia, New Zealand, Australia, Japan and the USA were among the 120 scientists and industry representatives from the 20 countries who participated at the meeting.

„Reliable geothermal technologies are in demand worldwide. Even countries with a long experience in geothermal energy such as Indonesia and New Zealand are interested in the results acquired in I-GET”, says Dr. Ernst Huenges. Therefore, the GFZ is further developing its geothermal research and is currently setting up an International Centre for Geothermal Research, which will, in particular, carry out application-oriented large-scale projects on a national and international level.

Source: Helmholtz Association of German Research Centres

CLEMSON, SC—In areas of the U.S. where golfers can enjoy the game year-round, winter temperatures, foot and equipment traffic, and frost can wreak havoc on healthy greens and present challenges for course managers and owners.

Creeping bentgrass (Agrostis stolonifera var. palustris Huds.), a turfgrass commonly used on golf course putting greens, is often preferred because of its year-round green color, ball roll, and playability. But managing bentgrass turf presents unique challenges from temperature fluctuations and frost, which can result in delayed tee times for golfers and lost revenue for course owners. Winter traffic from golfers, equipment, and animals can also cause damage and discolor greens.

In response to this common golf course management issue, researchers at Clemson University initiated a study to determine the impact of foot and mower traffic on winter bentgrass performance. The study determined that time and type of traffic significantly influenced bentgrass winter performance,

“This study indicates bentgrass damage resulting from winter traffic is limited to winter and early spring months, and full recovery should be expected by summer”, explained Haibo Liu, lead author of the research study published in the American Society for Horticultural Science journal HortScience. “During winter months, decisions regarding golf course set-up and the timing of play are important when temperatures approach zero degrees Centigrade. Often, tee times (during winter) are delayed or canceled, resulting in lost revenue and tension between golfers and course superintendents.”

The report recommended that golf course practitioners should proceed cautiously when allowing traffic on turfgrass immediately after a frost melt, and concluded that, although bentgrass suffers damage and discoloration resulting from winter traffic (in the eastern part of the transition zone), full recovery should be expected in the spring when temperatures remain above freezing.

Source: American Society for Horticultural Science

CLEMSON — Clemson University space physicists have traveled around the world to launch rockets to test atmospheric conditions.

This shows the fourth launch of a rocket at Poker Flat Research Range. Center: time exposure of first- and second-stage firetrail. Background: auroral arc in the north.Scientists most recently launched a salvo of four rockets over Alaska to study turbulence in the upper atmosphere. The launches took place at Poker Flat Research Range north of Fairbanks as part of a NASA sounding rocket campaign.

Associate professor of physics and astronomy Gerald Lehmacher is the principal investigator for the experiment and was assisted by graduate students Shelton Simmons and Liyu Guo.

“After six days of cloudy and snowy weather, we had perfect conditions with a clear, moonless night sky over interior Alaska,” said Lehmacher. “We needed excellent viewing conditions from three camera sites to photograph the luminescent trails the payloads produced in the upper atmosphere.”

The rockets were 35-foot, two-stage Terrier Orions. They released trimethyl aluminum that creates a glowing vapor trail nearly 87 miles up. Sensitive cameras on the ground track the trails. From that Lehmacher and his team can analyze upper-atmospheric winds by tracking how the vapor trails form, billow, disperse and diffuse. Two of the rockets had an additional deployable payload with instrumentation to measure electron density and neutral temperature and turbulence.

The instrumented sections are a collaboration of Clemson with Penn State University and the Leibniz-Institute for Atmospheric Physics in Germany. The University of Alaska assisted in the study with ground-based laser radar and other optical instruments. The project is sponsored by a NASA grant for three years.

In January, Clemson physicists traveled to Norway to carry out a joint experiment with Japanese scientists to study atmospheric winds and circulation from heating created by electrical currents associated with Northern Lights displays. The measurements were made with instruments flown on a Japanese S-310 rocket launched from the Andoya Rocket Range in northern Norway, as well as a suite of sensitive radar and camera instruments on the ground.

Source: Clemson University

Live sustainably just because it’s the right thing to do. Do you “hope” that everyone will see the light and start living more sustainably to save the environment? If so, you may be doing more harm than good.

So say an environmental scientist and an environmental ethicist in a provocative essay in the March 2009 issue of the international journal, The Ecologist. John Vucetich, assistant professor of animal ecology at Michigan Technological University, and Michael Nelson, associate professor of environmental ethics at Michigan State University, challenge the widespread belief that hope can motivate people to solve overwhelming social and environmental problems.

“Is hope a placebo, a distraction, merely sowing the seeds of disillusionment?” they ask, in an opinion piece titled “Abandon Hope.” The authors, co-founders and directors of the Conservation Ethics Group, an of environmental ethics consultancy, examine the proper role of hope in environmentalism. They suggest that hope’s alternative is not hopelessness or despair, but rather the inherent virtue of “doing the right thing.”

For decades, say Vucetich and Nelson, we have been hammered by the ceaseless thunder of messages predicting imminent environmental cataclysm: global climate change, air and water pollution, destruction of wildlife habitat, holes in the ozone. The response of environmentalists—from Al Gore to Jane Goodall—to this persistent message of hopelessness has focused on the need to remain hopeful.

But hope may actually be counter-productive, Vucetich and Nelson suggest. “I have little reason to live sustainably if the only reason to do so is to hope for a sustainable future, because every other message I receive suggests that disaster is guaranteed,” they explain.

People are hearing radically contradictory messages:

* Scientists present evidence that profound environmental disaster is imminent.
* It is urgent to live up to an extremely high standard of sustainable living.
* The reason to live sustainably is that doing so gives hope for averting disaster.
* Yet disaster is inevitable.

“Given a predisposition to mistrust authorities, such contradictions justifiably elicit mistrust,” say Vucetich and Nelson.

If hope for averting environmental disaster is not the right reason to live sustainably, what is? The scholars say we must provide people with reasons to live sustainably that are rational and effective, based on virtues rather than consequences. That means equating sustainable living not with hope for a better future, but with basic virtues such as sharing and caring, virtues that we recognize as good in themselves and fundamentally the right way to live in the present, they explain.

One advantage to such an approach is that it can motivate even people who do not believe that we are on the brink of environmental disaster, Vucetich and Nelson point out. It also clarifies the connection between environmental and social problems, a connection many people fail to grasp.

“Instead of hope, we need to provide young people with reasons to live sustainably that are rational and effective,” they say. “We need to lift up examples of sustainable living motivated by virtue more than by a dubious belief that such actions will avert environmental disaster.”

Source:Michigan Technological University.

ATHENS, Ohio – In the Mesozoic Era, 70 million years before birds first conquered the skies, pterosaurs dominated the air with sparrow- to Cessna-sized wingspans. Researchers suspected that these extinct reptiles sustained flight through flapping, based on fossil evidence from the wings, but had little understanding of how pterosaurs met the energetic demands of active flight.

A new study published today in the journal PLoS ONE by researchers from Ohio University, College of the Holy Cross and the University of Leicester explains how balloon-like air sacs, which extended from the lungs to inside the skeleton of pterosaurs, provided an efficient breathing system for the ancient beasts. The system reduced the density of the body in pterosaurs, which in turn allowed for the evolution of the largest flying vertebrates.

“We offer a reconstruction of the breathing system in pterosaurs, one that proposes the existence of a mechanism with the same essential structure to that of modern birds — except 70 million years earlier,” said study co-author Leon Claessens, an assistant professor of biology at the College of the Holy Cross.

The system would have facilitated the necessary gas exchange to enable sustained activity, added co-author Patrick O’Connor, an assistant professor of biomedical sciences at the Ohio University College of Osteopathic Medicine.

Claessens and O’Connor were inspired to conduct the study after David Unwin of the University of Leicester, then curator at the Natural History Museum in Berlin, showed them an extraordinarily preserved pterosaur in 2003. The scientists thought the specimen might finally shed light on how the animals powered sustained flight.

“The shape and size of the rib segments that articulate with the sternum indicate that the ribcage was mobile, contrary to previous ideas,” Claessens said.

Unique and previously unrecognized projections on the ribs provided important leverage for the muscles that power lung ventilation, he added.

Because fossils rarely preserve soft tissues, the research team conducted a comparative study that included pterosaurs, birds and crocodilians in order to get a better understanding of the relationships among air sacs, lung structure and the skeleton. By using X-ray movies and CT scans, the group characterized how the skeleton works to move air through the lungs in living animals, and also how to identify the signature traces left on bones that have been invaded by air sacs.

Not only do the extinct pterosaurs show evidence that their bones that were invaded by air sacs, but patterns of pneumaticity throughout the entire skeleton of different pterosaur species parallel trends identified in many living bird groups. For example, there is a direct relationship between the proportion of the skeleton invaded by air sacs and the absolute body size of an animal.

“Whereas small-bodied pterosaurs and birds typically pneumatize only a restricted part of the backbone, larger-bodied species routinely pneumatize most bones of the body, including the wing skeleton out to the ends of the fingers,” O’Connor said.

Such modifications of the skeleton would have reduced bone density and resolved a major problem with sustaining flight in large-bodied pterosaurs: the energetic cost of keeping a heavy body up in the air. Density reduction of the skeleton in pterosaurs may have been beneficial, particularly so in the aerial giants—just as it appears to be in the largest flying birds today.

Air sacs in birds also serve other purposes, such as for visual displays and the production of sound, the researchers said. The existence of an analogous air-sac system in pterosaurs highlights new areas of research in which paleobiologists can explore aspects of pterosaurian biology.

Source: Ohio University.