The 500 million years ocean history

Brachiopod Paraspirifer bownockeri from the Middle Devonian of Ohio (USA); Width: 5.6 cm. Picture: U. Jansen, Senckenberg Museum, Frankfurt am Main.

GEOMAR coordinates European research and education project BASE-LiNE Earth
02.03.2015 / Kiel. As the history of the oceans can be reconstructed in the past 500 million based on calcareous shells of fossil marine life, busy to date with the research project BASE-LiNE Earth. At the same time it enables talented young scientists and scientists a doctorate in an international research environment. The European Union supports the at GEOMAR Helmholtz Centre for Ocean Research Kiel coordinated project with a total of 3.8 million euros.

Almost all life on earth would be extinct - and that at least five times in the past 500 million years. The environmental changes that have each led to the mass extinction, the oceans play an important role in almost all cases. How did it happen that was phased so hostile to life as a life-giving force sea? And why have some species still survive? These are fundamental questions that will be examined in the next three years as part of the European research project BASE-LiNE Earth with innovative technologies and methods. In addition to answering the research questions BASE LiNE Earth serves as the training of talented young scholars and scientists who are recruited by means of a demanding selection process from all over the world and doctorate within the scope of the project. 

The EU promotes the GEOMAR Helmholtz Centre for Ocean Research Kiel coordinated project under a Marie Skłodowska-Curie Action in Horizon2020-Pogramm with a total of 3.8 million euros. The challenge for the future BASE-LiNE Earth-doctoral students, is to provide information to gain from distant epochs of earth's history. "When historians want to know about events 100 or 200 years ago, they visit libraries or archives where there is written evidence from these times," says project coordinator Prof. Dr. Anton Eisenhauer from GEOMAR. "We also use archives. 
However, they see something different. It is, for example, the calcareous shells of fossil brachiopods in which the relevant data on the chemical history of ocean water are stored reliably, "explains the Kiel geochemist on. 

The information is in the calcite shells of course not writing before, but encrypted in the chemical and mineralogical composition. "If we precise the ratios of elements such as strontium, magnesium, boron, or measure of the isotopic to each other, we can decrypt the information," says Professor Eisenhauer.

This then the age of the shell, as well as the chemical composition of the previous ocean and prevailing environmental conditions such as water temperature and the acidity of the water can be reconstructed. We know, for example, know that during the greatest mass extinction 251 million years ago, the ocean contained no oxygen and was acidified to a large extent. 

"This is similar to some scenarios that we expect for the future of our ocean," explains Professor Eisenhauer. Model calculations are carried out within the framework of the project should show how far the former changes in the environment are transferable to the present day. The challenge is to gain this information and to make it usable. In collaboration with industry partners modern analytical methods for obtaining information in cooperation with business partners in this area in the context of BASE-LiNE Earth therefore be generated and developed. The project involves a total of 21 scientific institutions from eight European countries and partners from Canada, Israel, Palestine and Australia involved. 15 PhD positions will announce the project this spring, two of them for the GEOMAR in Kiel. 

The Integrated School of Ocean Sciences (ISOS) provides at the University of Kiel for a comprehensive training program in which the scholars not only pursue their academic goals, but also learn more professional qualifications, skills and interact with each other.  In the coming years, the parties want to do their topic also by means of exhibitions and school supplies to a wider audience. "Of course we also bind the doctoral students, which thus also learn to communicate their work understandable," says the project coordinator. For more information on the project website www.baseline-earth.eu.

Source: Geomar

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Antarctic ozone hole similar to last year

The Antarctic ozone hole, which forms annually in the August to October period, reached its peak size on September 11, stretching to 9.3 million square miles (24.1 million square kilometers), roughly the same size as last year’s peak of 9.3 million square miles (24 million square kilometers) on September 16, 2013. This is an area similar in size to North America.

Ozone hole
This image, using NOAA satellite data, shows the ozone hole (areas below 220 Dobson units) in shades of red. (Credit: NOAA Visualization Lab; http://www.nnvl.noaa.gov/MediaDetail2.php?MediaID=1636&MediaTypeID=1)

In comparison, the largest ozone hole area recorded to date on a single day was on September 9, 2000, at 11.5 million square miles (29.9 million square kilometers). The ozone layer helps shield life on Earth from potentially harmful ultraviolet (UV) radiation that can cause skin cancer, damage plants and phytoplankton—the top of the oceanic food chain.

“The good news is that our measurements show less thinning of the ozone over the South Pole during the past three years,” said Bryan Johnson, a researcher with NOAA’s Earth System Research Laboratory in Boulder, Colorado. “However, the rate at which ozone thins during the month of September has remained about the same for the past two decades. A decrease in this rate will be an important sign of recovery.”

South Pole balloon-borne ozonesonde observations measured a minimum amount of 120 Dobson Units of ozone this year on September 29. Ozonesonde measurements of 250 Dobson Units in August are common just before the rapid destruction of ozone in September.  NOAA releases about 50-60 ozonesonde balloons per year since 1986 to measure the ozone layer at the South Pole.  Over the last 50 years satellite and ground-based records over Antarctica show ozone column amounts ranging from 100 to 400 Dobson units, which translates to about 1 millimeter (1/25 inch) to 4 millimeters (1/6 inch) of ozone in a layer if all of the ozone were brought down to the surface.

The Antarctic ozone hole began making a yearly appearance in the early 1980s, grew in size through the 1980s and has been consistently large since 1990, with annual variability attributed to stratospheric meteorological conditions over Antarctica. The hole is caused by chlorine released by manmade chemicals called chlorofluorocarbons or CFCs that were extensively used as aerosol sprays and in refrigerators.

Ozonesonde release
NOAA Corps LTJG Joseph Phillips releases an ozonesonde that's attached to a helium balloon. The instrument will rise 18 miles into the atmosphere to measure the thickness of ozone. (Credit: Chet Waggoner, NOAA)

These chlorine compounds lead to ozone depletion in certain upper atmospheric conditions. These conditions are at their peak over Antarctica as the dark cold winter gives way to the Antarctic spring in September. Just before the sun rises over Antarctica, extremely cold temperatures in the stratosphere allow for polar stratospheric clouds to form, a rare event in the earth’s atmosphere, but a regular occurrence in the winter over Antarctica. Chemical reactions on the cloud particles convert stable chlorine compounds into unstable or reactive forms. The sun light triggers reactive chlorine and ozone chemistry that depletes ozone in a large volume over Antarctica.

Scientists first made the connection that CFCs were depleting the earth’s protective layer in 1974. In 1987, 46 nations, including the U.S., signed the Montreal Protocol, a landmark agreement to phase out production of ozone-depleting chemicals. The slow recovery of this ozone layer is one of the great international efforts to restore the planet from manmade damage.

The 2014 level of ozone depleting substances over Antarctica has declined about 9 percent below the 2000 recorded maximum. But CFCs can remain in the atmosphere for more than 50 years. The ozone layer above Antarctica likely will not return to its 1980 state until about 2070, said Paul Newman, chief scientist for atmospheres at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Climate change may also affect the rate of ozone recovery by cooling the stratosphere, which can slow Antarctic ozone recovery.

“Year-to-year weather variability significantly impacts Antarctica ozone because warmer stratospheric temperatures can reduce ozone depletion,” said Paul A. Newman, chief scientist for atmospheres at NASA's Goddard Space Flight Center in Greenbelt, Maryland. “The ozone hole area is smaller than what we saw in the late-1990s and early 2000s, and we know that chorine levels are decreasing. However, we are still uncertain about whether a long-term Antarctic stratospheric temperature warming might be reducing this ozone depletion.”

Under the mandate of the Clean Air Act, NOAA and NASA scientists keep a close eye on the ozone layer’s health with satellite data, ground-based measurements and instruments sent up through the ozone layer via balloons. Together, these instruments provide a big picture of the thickness and area extent of the ozone hole. NOAA measures the thickness of the ozone using ground-based instruments and by sending balloons with measurement devices up 18 miles into the atmosphere from NOAA’s Antarctic station.

NOAA and NASA also use data taken by the Ozone Mapping Profiler Suite (OMPS) instrument on board the Suomi-National Polar-Orbiting Partnership satellite to monitor the earth’s ozone layer. This instrument replaced the NOAA Solar Backscatter UltraViolet/2 ozone profiler and NASA Total Ozone Mapping Spectrometer.  NOAA’s Climate Prediction Center has been monitoring the Earth’s ozone layer for over 30 years, analyzing ozone concentration at various altitudes in the ozone layer as well as the total column amount of ozone. These measurements provide a three dimensional perspective of the ozone layer. This provides the means to monitor the ozone layer’s health and to make sure it is on the road to recovery.

Source: NOAA

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Artificial light, biological clock disruptions, increase breast cancer risk, study finds

Employment as a flight attendant has been found to be related to an increased risk of breast cancer. Credit: © dmitrimaruta / Fotolia

The disruption of a person's circadian rhythm -- their 24-hour biological clock -- has been linked to an increased risk of breast cancer, according to new University of Georgia research. The culprit, in this study in particular, is artificial light.

"Exposure to artificial light leads to a significantly higher risk for developing breast cancer," said Chunla He, a biostatistics graduate student in the UGA College of Public Health. "To decrease the use of artificial light, people should avoid working at night and implement earlier bed times."

Her research, published in the International Archives of Occupational and Environmental Health, examined key studies that included risk factors for developing breast cancer.

"A large body of related research about circadian rhythms and breast cancer exists," He said. 

"However, these studies are inconsistent and have a variety of limitations."

Under the mentorship of Sara Wagner Robb, assistant professor of epidemiology in the College of Public Health, He turned to previous studies to see what the research revealed.

In addition to other relevant exposures, He examined studies on breast cancer and flight attendants, who typically work both day and night shifts. The flight attendants represented a group of workers particularly susceptible to disrupted circadian rhythms, which are heavily influenced by light.

In her analysis, He found that employment as a flight attendant was related to an increased risk of breast cancer.

"People naturally secrete the hormone melatonin, which helps to regulate the circadian rhythm," He said. "When the sleep-wake cycle is disrupted by artificial light, melatonin secretion is adversely affected."

Robb recommends spreading this information to shift workers so they understand the harms in disrupting their circadian rhythms.

"Individuals engaging in this type of work should be aware of these risks and may make efforts to adjust their circadian rhythms," she said. "Although additional studies are certainly needed, scientists are becoming increasingly aware of the health risks associated with night workers and others exposed to circadian-disrupting behaviors."

Robb and He also advise that future research needs to examine social constraints -- which may foster disruption of circadian rhythms -- on shift workers. Additionally, shift workers should contact their primary care physicians for personalized treatment and options.

"This information tells us the harm in disrupting our natural cycle," He said. "With this new analysis, we must be cautious in our exposure to artificial light."

The article was co-authored by Sonia Taj Anand, a former graduate student in the College of Public Health; Mark H. Ebell, professor of epidemiology; and John E. Vena, Medical University of South Carolina.

Source: University of Georgia

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NASA Goddard instrument makes first detection of organic matter on Mars

MSL Curiosity rover at "John Klein" drill site. This self-portrait of NASA's Mars rover Curiosity combines dozens of exposures taken by the rover's Mars Hand Lens Imager on Feb. 3, 2013 plus three exposures taken May 10, 2013 to show two holes (in lower left quadrant) where Curiosity used its drill on the rock target "John Klein". Credit: NASA/JPL-Caltech/MSSS

The team responsible for the Sample Analysis at Mars (SAM) instrument suite on NASA's Curiosity rover has made the first definitive detection of organic molecules at Mars. Organic molecules are the building blocks of all known forms of terrestrial life, and consist of a wide variety of molecules made primarily of carbon, hydrogen, and oxygen atoms. However, organic molecules can also be made by chemical reactions that don't involve life, and there is not enough evidence to tell if the matter found by the team came from ancient Martian life or from a non-biological process. Examples of non-biological sources include chemical reactions in water at ancient Martian hot springs or delivery of organic material to Mars by interplanetary dust or fragments of asteroids and comets.

The surface of Mars is currently inhospitable to life as we know it, but there is evidence that the Red Planet once had a climate that could have supported life billions of years ago. For example, features resembling dry riverbeds and minerals that only form in the presence of liquid water have been discovered on the Martian surface. The Curiosity rover with its suite of instruments including SAM was sent to Mars in 2011 to discover more about the ancient habitable Martian environment by examining clues in the chemistry of rocks and the atmosphere.

The organic molecules found by the team were in a drilled sample of the Sheepbed mudstone in Gale crater, the landing site for the Curiosity rover. Scientists think the crater was once the site of a lake billions of years ago, and rocks like mudstone formed from sediment in the lake. Moreover, this mudstone was found to contain 20 percent smectite clays. On Earth, such clays are known to provide high surface area and optimal interlayer sites for the concentration and preservation of organic compounds when rapidly deposited under reducing chemical conditions.

While the team can't conclude that there was life at Gale crater, the discovery shows that the ancient environment offered a supply of reduced organic molecules for use as building blocks for life and an energy source for life. Curiosity's earlier analysis of this same mudstone revealed that the environment offered water and chemical elements essential for life and a different chemical energy source.

"We think life began on Earth around 3.8 billion years ago, and our result shows that places on Mars had the same conditions at that time -- liquid water, a warm environment, and organic matter," said Caroline Freissinet of NASA's Goddard Space Flight Center in Greenbelt, Maryland. "So if life emerged on Earth in these conditions, why not on Mars as well?" Freissinet is lead author of a paper on this research submitted to the Journal of Geophysical Research-Planets.

The organic molecules found by the team also have chlorine atoms, and include chlorobenzene and several dichloroalkanes, such as dichloroethane, dichloropropane and dichlorobutane. Chlorobenzene is the most abundant with concentrations between 150 and 300 parts-per-billion. Chlorobenzene is not a naturally occurring compound on Earth. It is used in the manufacturing process for pesticides (insecticide DDT), herbicides, adhesives, paints and rubber. Dichloropropane is used as an industrial solvent to make paint strippers, varnishes and furniture finish removers, and is classified as a carcinogen.

It's possible that these chlorine-containing organic molecules were present as such in the mudstone. However, according to the team, it's more likely that a different suite of precursor organic molecules was in the mudstone, and that the chlorinated organics formed from reactions inside the SAM instrument as the sample was heated for analysis. Perchlorates (a chlorine atom bound to four oxygen atoms) are abundant on the surface of Mars. It's possible that as the sample was heated, chlorine from perchlorate combined with fragments from precursor organic molecules in the mudstone to produce the chlorinated organic molecules detected by SAM.

In 1976, the Gas Chromatograph Mass Spectrometer instrument on NASA's Viking landers detected two simple chlorinated hydrocarbons after heating Martian soils for analysis (chloromethane and dichloromethane). However they were not able to rule out that the compounds were derived from the instrument itself, according to the team. While sources within the SAM instrument also produce chlorinated hydrocarbons, they don't make more than 22 parts-per-billion of chlorobenzene, far below the amounts detected in the mudstone sample, giving the team confidence that organic molecules really are present on Mars.

The SAM instrument suite was built at NASA Goddard with significant elements provided by industry, university, and national and international NASA partners.

For this analysis, the Curiosity rover sample acquisition system drilled into a mudstone and filtered fine particles of it through a sieve, then delivered a portion of the sample to the SAM laboratory. SAM detected the compounds using its Evolved Gas Analysis (EGA) mode by heating the sample up to about 875 degrees Celsius (around 1,600 degrees Fahrenheit) and then monitoring the volatiles released from the sample using a quadrupole mass spectrometer, which identifies molecules by their mass using electric fields. SAM also detected and identified the compounds using its Gas Chromatograph Mass Spectrometer (GCMS) mode. In this mode, volatiles are separated by the amount of time they take to travel through a narrow tube (gas chromatography -- certain molecules interact with the sides of the tube more readily and thus travel more slowly) and then identified by their signature mass fragments in the mass spectrometer.

The first evidence for elevated levels of chlorobenzene and dichloroalkanes released from the mudstone was obtained on Curiosity Sol 290 (May 30, 2013) with the third analysis of the Cumberland sample at Sheepbed. The team spent over a year carefully analyzing the result, including conducting laboratory experiments with instruments and methods similar to SAM, to be sure that SAM could not be producing the amount of organic material detected.

"The search for organics on Mars has been extremely challenging for the team," said Daniel Glavin of NASA Goddard, a co-author on the paper. "First, we need to identify environments in Gale crater that would have enabled the concentration of organics in sediments. Then they need to survive the conversion of sediment to rock, where pore fluids and dissolved substances may oxidize and destroy organics. Organics can then be destroyed during exposure of rocks at the surface of Mars to intense ionizing radiation and oxidants. Finally, to identify any organic compounds that have survived, we have to deal with oxychlorine compounds and possibly other strong oxidants in the sample which will react with and combust organic compounds to carbon dioxide and chlorinated hydrocarbons when the samples are heated by SAM."

As part of Curiosity's plan for exploration, an important strategic goal was to sample rocks that represent different combinations of the variables thought to control organic preservation. "The SAM and Mars Science Laboratory teams have worked very hard to achieve this result," said John Grotzinger of Caltech, Mars Science Laboratory's Project Scientist. "Only by drilling additional rock samples in different locations, and representing different geologic histories were we able to tease out this result. At the time we first saw evidence of these organic molecules in the Cumberland sample it was uncertain if they were derived from Mars, however, additional drilling has not produced the same compounds as might be predicted for contamination, indicating that the carbon in the detected organic molecules is very likely of Martian origin."

Source: nasa

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People ate mammoth; Dogs got reindeer

Artist's depiction of cave painting of primitive hunt

Biogeologists have shown how Gravettian people shared their food 30,000 years ago.

Předmostí I is an exceptional prehistoric site located near Brno in the Czech Republic. Around 30,000 years ago it was inhabited by people of the pan-European Gravettian culture, who used the bones of more than 1000 mammoths to build their settlement and to ivory sculptures. Did prehistoric people collect this precious raw material from carcasses -- easy to spot on the big cold steppe -- or were they the direct result of hunting for food? This year-round settlement also yielded a large number of canids remains, some of them with characteristics of Palaeolithic dogs. Were these animals used to help hunt mammoths?

To answer these two questions, Tübingen researcher Hervé Bocherens and his international team carried out an analysis of carbon and nitrogen stable isotopes in human and animal fossil bones from the site. Working with researchers from Brno and Brussels, the researchers were able to test whether the Gravettian people of Předmostí ate mammoth meat and how the "palaeolithic dogs" fit into this subsistence picture.

They found that humans did consume mammoth -- and in large quantities. Other carnivores, such as brown bears, wolves and wolverines, also had access to mammoth meat, indicating the high availability of fresh mammoth carcasses, most likely left behind by human hunters. Surprisingly, the dogs did not show a high level of mammoth consumption, but rather consumed essentially reindeer meat that was not the staple food of their owners. A similar situation is observed in traditional populations from northern regions, who often feed their dogs with the food that they do not like. These results also suggest that these early dogs were restrained, and were probably used as transportation helpers.

These new results provide clear evidence that mammoth was a key component of prehistoric life in Europe 30,000 years ago, and that dogs were already there to help.

Source: Universitaet Tübingen

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Odor that smells like blood: Single component powerful trigger for large carnivores

African wild dogs compete for a log impregnated with blood or a single component. Both were equally attractive. Credit: Linköping University

People find the smell of blood unpleasant, but for predatory animals it means food. When behavioural researchers at Linköping University in Sweden wanted to find out which substances of blood trigger behavioural reactions, they got some unexpected results.

Matthias Laska is professor of zoology, specialising in the sense of smell. For some time his focus has been on scents that directly affect the behaviour of animals.

"For predators, food scents are particularly attractive, and much of this has to do with blood. We wanted to find out which chemical components create the scent of blood," he says.

The study, conducted at Kolmården Wildlife Park, found that for the animals, one particular component of blood odour was just as engaging as the blood odour itself.

"It's a completely new discovery that raises interesting questions on evolution," says Prof Laska.

The study has been published in the scientific journal PLOS ONE.

When Prof Laska did a search for the contents of volatile substances in mammalian blood, he found nothing. Human blood has been analysed for disease markers, but we have very little information on the substances that give blood its characteristic scent.

A master's student was sent to Friedrich-Alexander-Universität in Erlangen Germany, to analyse mammalian blood with the help of gas chromatography and mass spectrometry, methods used for separating and identifying chemical compounds in a sample. The machine detected some 30 substances, of which some are decomposition products from fats. But the machine lost the job to the human scent experts who had also been engaged. They identified scents that the gas chromatograph missed completely.

One substance stood out: an aldehyde called trans-4,5-epoxy-(E)-2-decenal, which emits the typical metallic scent that humans associate with blood.

Once the researchers had identified a scent candidate that the predators should be attracted to, they wanted to test whether the predators were actually attracted to it in reality. So they designed a study to be conducted at Kolmården Wildlife Park, involving four predator species. How would the four predators -- Asian wild dogs, African wild dogs, South American bush dogs and Siberian tigers -- react when they caught a whiff of the scent?

Half-metre long wooden logs were impregnated with four different liquids: lab-produced aldehyde, horse blood, fruit essence, and a near-odourless solvent. The animals were exposed to one scent per day in their regular enclosure, while a group of students carefully observed their behaviour.

The results were unequivocal. The logs containing aldehyde were just as attractive stimuli as those containing blood, while the two other logs aroused little interest. The commonest behaviours were sniffing, licking, biting, pawing and toying. The tiger was the most persistent, while the South American bush dogs lost interest more quickly than the other species.

The study is the first to show that a single component can be just as attractive as the complex odour.

"How this has developed through evolution is an interesting question. Perhaps there is a common denominator for all mammalian blood," says Prof Laska.

He has plans for several follow-ups of the study, including how prey animals such as mice react to blood odour.

For the wildlife park, the study provided results that can be used in its daily operations. Animals in captivity require stimulation, so as not to deteriorate or become fat. The odourised logs can be a popular addition to the animal's environment.

Source: Linköping University

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Sunlight, not microbes, key to carbon dioxide in Arctic

Terrestrial organic matter is shown spilling into a lake. Credit: Image courtesy of Oregon State University

The vast reservoir of carbon stored in Arctic permafrost is gradually being converted to carbon dioxide (CO2) after entering the freshwater system in a process thought to be controlled largely by microbial activity.

However, a new study -- funded by the National Science Foundation and published this week in the journal Science -- concludes that sunlight and not bacteria is the key to triggering the production of CO2 from material released by Arctic soils.

The finding is particularly important, scientists say, because climate change could affect when and how permafrost is thawed, which begins the process of converting the organic carbon into CO2.

"Arctic permafrost contains about half of all the organic carbon trapped in soil on the entire Earth -- and equals an amount twice of that in the atmosphere," said Byron Crump, an Oregon State University microbial ecologist and co-author on the Science study. "This represents a major change in thinking about how the carbon cycle works in the Arctic."

Converting soil carbon to carbon dioxide is a two-step process, notes Rose Cory, an assistant professor of earth and environmental sciences at the University of Michigan, and lead author on the study. First, the permafrost soil has to thaw and then bacteria must turn the carbon into greenhouse gases -- carbon dioxide or methane. While much of this conversion process takes place in the soil, a large amount of carbon is washed out of the soils and into rivers and lakes, she said.

"It turns out, that in Arctic rivers and lakes, sunlight is faster than bacteria at turning organic carbon into CO2," Cory said. "This new understanding is really critical because if we want to get the right answer about how the warming Arctic may feedback to influence the rest of the world, we have to understand the controls on carbon cycling.

"In other words, if we only consider what the bacteria are doing, we'll get the wrong answer about how much CO2 may eventually be released from Arctic soils," Cory added.

The research team measured the speed at which both bacteria and sunlight converted dissolved organic carbon into carbon dioxide in all types of rivers and lakes in the Alaskan Arctic, from glacial-fed rivers draining the Brooks Range to tannin-stained lakes on the coastal plain. Measuring these processes is important, the scientists noted, because bacteria types and activities are variable and the amount of sunlight that reaches the carbon sources can differ by body of water.

In virtually all of the freshwater systems they measured, however, sunlight was always faster than bacteria at converting the organic carbon into CO2.

"This is because most of the fresh water in the Arctic is shallow, meaning sunlight can reach the bottom of any river -- and most lakes -- so that no dissolved organic carbon is kept in the dark," said Crump, an associate professor in Oregon State's College of Earth, Ocean, and Atmospheric Sciences. "Also, there is little shading of rivers and lakes in the Arctic because there are no trees."

Another factor limiting the microbial contribution is that bacteria grow more slowly in these cold, nutrient-rich waters.

"Light, therefore, can have a tremendous effect on organic matter," University of Michigan's Cory pointed out.

The source of all of this organic carbon is primarily tundra plants -- and it has been building up for hundreds of thousands of years, but doesn't completely break down immediately because of the Arctic's cold temperatures. Once the plant material gets deep enough into the soil, the degradation stops and it becomes preserved, much like peat.

"The level of thawing only gets to be a foot deep or so, even in the summer," Crump said. "Right now, the thaw begins not long before the summer solstice. If the seasons begin to shift with climate change -- and the thaw begins earlier, exposing the organic carbon from permafrost to more sunlight -- it could potentially trigger the release of more CO2."

The science community has not yet been able to accurately calculate how much organic carbon from the permafrost is being converted into CO2, and thus it will be difficult to monitor potential changes because of climate change, they acknowledge.

"We have to assume that as more material thaws and enters Arctic lakes and rivers, more will be converted to CO2," Crump said. "The challenge is how to quantify that."

Some of the data for the study was made available through the National Science Foundation's Arctic Long-Term Ecological Research project, which has operated in the Arctic for nearly 30 years.

Source:  Oregon State University

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Nitrogen fingerprint in biomolecules could be from early sun

Ultraviolet light splits more readily splits molecules of nitrogen gas if one or both are the heavier isotope, nitrogen-15. Free nitrogen atoms combine with hydrogen to form ammonia molecules enriched in nitrogen-15. Credit: Image courtesy of University of California - San Diego

Chemical fingerprints of the element nitrogen vary by extremes in materials from the molecules of life to the solar wind to interstellar dust. Ideas for how this great variety came about have included alien molecules shuttled in by icy comets from beyond our solar system and complex chemical scenarios.

New experiments using a powerful source of ultraviolet light have shown that no extra-solar explanation is needed and the chemistry is straight forward, scientists from the University of California, San Diego, Hebrew University and UCLA report in the early online edition of the Proceedings of the National Academy of Sciences the week of September 29.

Nitrogen occurs in two stable forms. Nitrogen-14, with an equal number of protons and neutrons in its nucleus, is most abundant. Nitrogen-15, with an extra neutron, is far more rare, but biological molecules like proteins have larger proportions; they're enriched in nitrogen-15 relative to the nitrogen gas in Earth's atmosphere. And Earth's atmosphere itself has relatively more nitrogen-15 than other sources, such as the solar wind and Jupiter's atmosphere.

Samples from the icy comet Wild 2, retrieved by NASA's Stardust mission, and several kinds of meteorites also have relatively more nitrogen-15, and within the inhomogenous mix that makes up stony meteorites are inclusions, individual crystals that can have extremely high proportions of nitrogen-15. These observations led to the idea that the building blocks of life could have been 'seeded' on Earth, delivered perhaps by comet.

The new experiments render that hypothesis unnecessary. "We can generate this nitrogen enrichment inside the solar system. You can form all these building blocks of life inside our solar system. You don't have to bring the pieces in from outside," said Subrata Chakraborty, a project scientist in chemistry at UC San Diego and lead author of the report.

By shining a bright beam of very short wave ultraviolet light through nitrogen and hydrogen gas, Chakraborty and colleagues generated ammonia with drastically skewed ratios of nitrogen-15 relative to that found in the initial gas, which matched that of Earth's atmosphere. Pairs of nitrogen atoms -- the molecules of the gas -- were more likely to be split by UV photons if one or both atoms are the heavier version. Those freed nitrogen atoms recombined with hydrogen to form ammonia.

Ammonia molecules, a nitrogen atom bound to three hydrogen atoms, makes up a fundamental chemical group, the 'amines' the characterize amino acids, which link up in long chains to form proteins. They also join aromatic rings of carbon to form nitrogenous bases, the information carrying components of DNA and RNA. And RNA is how many think life got its start.

Light like this, with wavelengths this short, doesn't make it to Earth anymore. It's deflected by Earth's atmosphere. In fact, the experiments took place in a custom-engineered vacuum chamber aligned with the Lawrence Berkeley National Laboratory's Advanced Light Source synchrotron and were a challenge to pull off.

The chemical events that produced amines with extra nitrogen-15 would have happened long ago, probably in the icy outer reaches of the early solar nebula said Mark Thiemens, professor of chemistry at UC San Diego who directed the work. "It's the right time for this to have happened: before planets, before life."

Additional authors include Harel Muskatel of Hebrew University in Jerusalem, Teresa Jackson of UC San Diego, Musahid Ahmed of Lawrence Berkeley National Laboratory and R.D. Levine of Hebrew University and UCLA. NASA's Cosmochemistry and Origins of Solar System programs funded this work. The U.S. Department of Energy supports the operation of the Advanced Light Source.

Source:  University of California - San Diego

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Traces of Martian biological activity could be locked inside a meteorite

Ejected from Mars after an asteroid crashed on its surface, the meteorite, named Tissint, fell on the Moroccan desert on July 18, 2011, in view of several eyewitnesses. Upon examination, the alien rock was found to have small fissures that were filled with carbon-containing matter. Credit: Copyright Alain Herzog/EPFL

Did Mars ever have life? Does it still? A meteorite from Mars has reignited the old debate. An international team that includes scientists from EPFL has published a paper in the scientific journal Meteoritics and Planetary Sciences, showing that martian life is more probable than previously thought.

"So far, there is no other theory that we find more compelling," says Philippe Gillet, director of EPFL's Earth and Planetary Sciences Laboratory. He and his colleagues from China, Japan and Germany performed a detailed analysis of organic carbon traces from a Martian meteorite, and have concluded that they have a very probable biological origin. The scientists argue that carbon could have been deposited into the fissures of the rock when it was still on Mars by the infiltration of fluid that was rich in organic matter.

Ejected from Mars after an asteroid crashed on its surface, the meteorite, named Tissint, fell on the Moroccan desert on July 18, 2011, in view of several eyewitnesses. Upon examination, the alien rock was found to have small fissures that were filled with carbon-containing matter. Several research teams have already shown that this component is organic in nature. But they are still debating where the carbon came from.

Maybe biological, but not from our planet

Chemical, microscopic and isotope analysis of the carbon material led the researchers to several possible explanations of its origin. They established characteristics that unequivocally excluded a terrestrial origin, and showed that the carbon content were deposited in the Tissint's fissures before it left Mars.

The researchers challenged previously described views (Steele et al., Science, 2012) proposing that the carbon traces originated through the high-temperature crystallization of magma. According to the new study, a more likely explanation is that liquids containing organic compounds of biological origin infiltrated Tissint's "mother" rock at low temperatures, near the Martian surface.

These conclusions are supported by several intrinsic properties of the meteorite's carbon, e.g. its ratio of carbon-13 to carbon-12. This was found to be significantly lower than the ratio of carbon-13 in the CO2 of Mars's atmosphere, previously measured by the Phoenix and Curiosity rovers. Moreover, the difference between these ratios corresponds perfectly with what is observed on Earth between a piece of coal -- which is biological in origin -- and the carbon in the atmosphere. The researchers note that this organic matter could also have been brought to Mars when very primitive meteorites -- carbonated chondrites -- fell on it. However, they consider this scenario unlikely because such meteorites contain very low concentrations of organic matter.

"Insisting on certainty is unwise, particularly on such a sensitive topic," warns Gillet. "I'm completely open to the possibility that other studies might contradict our findings. However, our conclusions are such that they will rekindle the debate as to the possible existence of biological activity on Mars -- at least in the past."

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Source: Ecole Polytechnique Fédérale de Lausanne

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Invasive plant wins competition against its native cousin

This iamge depicts root nodules. Credit: University of Illinois

Because of its aggressive behavior and its harmful effects, the invasive prairie plant Lespedeza cuneata has been added to several noxious weed lists. Research at the University of Illinois on how soil bacteria interact with the plants' roots to form nodules that fix nitrogen demonstrated that the invasive variety had superior performance when pitted against the native plant variety Lespedeza virginica.

"We expected Lespedeza cuneata to be a strong competitor when up against its native cousin that's planted primarily for prairie restoration," said U of I microbial ecologist Tony Yannarell. "There are a number of studies showing that L. cuneata grows quickly, is able to shade out its competitors, and has a high rate of nitrogen fixation, which allows it to 'self-fertilize' on unproductive soils."

Yannarell explained that Lespedeza plants establish a "partnership" with bacteria in the soil to form nodules that fix nitrogen. "We wanted to demonstrate that the partners in this symbiosis matter," he said.

Because the nitrogen-fixing gene is in the bacteria, the first step in the research was to identify bacteria that have the gene. "We started with isolating a pool of 50 bacteria [from the root nodules of invasive and native Lespedezas] and discovered that some of them weren't traditional nodule-forming bacteria."

Ultimately, seven bacteria were identified and used in a three-month greenhouse experiment in which various combinations of native and invasive varieties of Lespedeza were grown together in pots. Of the seven, five bacteria were found to benefit the invader and two did not benefit either of the plant varieties.

"We were hoping to be able to change the degree of competitiveness by using different varieties of Lespedeza by varying the bacteria," Yannarell said. "It turned out that none of the bacteria seemed to be better for the native plant.

"A really intriguing pattern that we found is that a lot of these strains of bacteria that are good for the invader belong to the Bradyrhizobium genus of bacteria that's been shown in other parts of the world to be good at fixing nitrogen so this was one more confirmation of that information," Yannarell said.

Yannarell said that this study provides yet another piece in the ecological puzzle.

The invasive Lespedeza cuneata was intentionally brought into the United States from Japan near the end of the 1800s. At the time, people liked its nitrogen-fixing capacity and soil fertilization. It was intended to be used to stabilize river banks and rehabilitate poor soil. Yannarell said that it has been recommended as wildlife forage, and some think that it has tannins that can act as a deworming treatment for goats. Now, however, it's considered to be a noxious weed that grows in the South and Midwest. It is commonly called silky bush clover.

Yannarell stressed that there are a lot of different species of Lespedeza that are native to North America and indicative of high-quality prairie. Although Lespedeza cuneata isn't a plant that would be intentionally planted by prairie restorationists, it has been seen in prairie seed mixes.

"Invasive Lespedeza cuneata and native Lespedeza virginica experience asymmetrical benefits from rhizobial symbionts," was published in Plant and Soil and was co-authored by Lingzi Hu, Ryan R. Busby, and Dick L. Gebhart. The work was supported by a grant from the U.S. Army Engineer Research and Development Center and by the Cooperative State Research, Education and Extension Service, U.S. Department of Agriculture.

Source: University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES)

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Ancient, hydrogen-rich waters deep underground around the world: Waters could support isolated life

Energy-rich waters discharge kilometers below the surface in a South African mine.
Credit: G. Borgonie, 2014

A team of scientists, led by the University of Toronto's Barbara Sherwood Lollar, has mapped the location of hydrogen-rich waters found trapped kilometres beneath Earth's surface in rock fractures in Canada, South Africa and Scandinavia.

Common in Precambrian Shield rocks -- the oldest rocks on Earth -- the ancient waters have a chemistry similar to that found near deep sea vents, suggesting these waters can support microbes living in isolation from the surface.

The study, to be published in Nature on December 18, includes data from 19 different mine sites that were explored by Sherwood Lollar, a geoscientist at U of T's Department of Earth Sciences, U of T senior research associate Georges Lacrampe-Couloume, and colleagues at Oxford and Princeton universities.

The scientists also explain how two chemical reactions combine to produce substantial quantities of hydrogen, doubling estimates of global production from these processes which had previously been based only on hydrogen coming out of the ocean floor.

"This represents a quantum change in our understanding of the total volume of Earth's crust that may be habitable," said Sherwood Lollar.

"Until now, none of the estimates of global hydrogen production sustaining deep microbial populations had included a contribution from the ancient continents. Since Precambrian rocks make up more than 70 per cent of the surface of Earth's crust, Sherwood Lollar likens these terrains to a "sleeping giant," a huge area that has now been discovered to be a source of possible energy for life," she said.

One process, known as radiolytic decomposition of water, involves water undergoing a breakdown into hydrogen when exposed to radiation. The other is a chemical reaction called serpentization, a mineral alteration reaction that is common in such ancient rocks.
This study has important implications for the search for deep microbial life. Quantifying the global hydrogen budget is key to understanding the amount of Earth's biomass that is in the subsurface, as many deep ecosystems contain chemolithotrophic -- so-called "rock-eating" -- organisms that consume hydrogen. In the deep gold mines of South Africa, and under the sea, at hydrothermal vents where breaks in the fissure of Earth's surface that release geothermally heated waters -- hydrogen-rich fluids host complex microbial communities that are nurtured by the chemicals dissolved in the fluids. This study identifies a global network of sites with hydrogen-rich waters that will be targeted for exploration for deep life over the coming years.

Further, because Mars -- like the Precambrian crust -- consists of billions-of-year-old rocks with hydrogen-producing potential, this finding has ramifications for astrobiology. "If the ancient rocks of Earth are producing this much hydrogen, it may be that similar processes are taking place on Mars," said Sherwood Lollar.

Other key members of the research team are Chris Ballentine of Oxford University, Tulis Onstott at Princeton University and Georges Lacrampe-Couloume of the University of Toronto. The research was funded by the Canada Research Chairs program, the Natural Sciences & Engineering Research Council, the Sloan Foundation Deep Carbon Observatory, the Canadian Space Agency and the National Science Foundation.

Source: University of Toronto

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New conversion process turns biomass 'waste' into lucrative chemical products

Purdue's R.B. Wetherill Professor of Chemistry, holds a small vial containing results of a new catalytic process that can convert the lignin in wood into high-value chemical products for use in fragrances and flavoring.
Credit: Purdue University photo/Mark Simons

A new catalytic process is able to convert what was once considered biomass waste into lucrative chemical products that can be used in fragrances, flavorings or to create high-octane fuel for racecars and jets.

A team of researchers from Purdue University's Center for Direct Catalytic Conversion of Biomass to Biofuels, or C3Bio, has developed a process that uses a chemical catalyst and heat to spur reactions that convert lignin into valuable chemical commodities. Lignin is a tough and highly complex molecule that gives the plant cell wall its rigid structure.

Mahdi Abu-Omar, the R.B. Wetherill Professor of Chemistry and Professor of Chemical Engineering and associate director of C3Bio, led the team.

"We are able to take lignin -- which most biorefineries consider waste to be burned for its heat -- and turn it into high-value molecules that have applications in fragrance, flavoring and high-octane jet fuels," Abu-Omar said. "We can do this while simultaneously producing from the biomass lignin-free cellulose, which is the basis of ethanol and other liquid fuels. We do all of this in a one-step process."

Plant biomass is made up primarily of lignin and cellulose, a long chain of sugar molecules that is the bulk material of plant cell walls. In standard production of ethanol, enzymes are used to break down the biomass and release sugars. Yeast then feast on the sugars and create ethanol.

Lignin acts as a physical barrier that makes it difficult to extract sugars from biomass and acts as a chemical barrier that poisons the enzymes. Many refining processes include harsh pretreatment steps to break down and remove lignin, he said.

"Lignin is far more than just a tough barrier preventing us from getting the good stuff out of biomass, and we need to look at the problem differently," Abu-Omar said. "While lignin accounts for approximately 25 percent of the biomass by weight, it accounts for approximately 37 percent of the carbon in biomass. As a carbon source lignin can be very valuable, we just need a way to tap into it without jeopardizing the sugars we need for biofuels."

The Purdue team developed a process that starts with untreated chipped and milled wood from sustainable poplar, eucalyptus or birch trees. A catalyst is added to initiate and speed the desired chemical reactions, but is not consumed by them and can be recycled and used again. A solvent is added to the mix to help dissolve and loosen up the materials. The mixture is contained in a pressurized reactor and heated for several hours. The process breaks up the lignin molecules and results in lignin-free cellulose and a liquid stream that contains two additional chemical products, Abu-Omar said.

The liquid stream contains the solvent, which is easily evaporated and recycled, and two phenols, a class of aromatic hydrocarbon compounds used in perfumes and flavorings. A commonly used artificial vanilla flavoring is currently produced using a phenol that comes from petroleum, he said.

The team also developed an additional process that uses another catalyst to convert the two phenol products into high-octane hydrocarbon fuel suitable for use as drop-in gasoline. The fuel produced has a research octane rating greater than100, whereas the average gas we put into our cars has an octane rating in the eighties, he said.

The processes and resulting products are detailed in a paper published online in the Royal Society of Chemistry journal Green Chemistry. The U.S. Department of Energy funded the research.

In addition to Abu-Omar, co-authors include Trenton Parsell, a visiting scholar in the Department of Chemistry; chemical engineering graduate students Sara Yohe, John Degenstein, Emre Gencer, and Harshavardhan Choudhari; chemistry graduate students Ian Klein, Tiffany Jarrell, and Matt Hurt; agricultural and biological engineering graduate student Barron Hewetson; Jeong Im Kim, associate research scientist in biochemistry; Basudeb Saha, associate research scientist in chemistry; Richard Meilan, professor of forestry and natural reserouces; Nathan Mosier, associate professor of agricultural and biological engineering; Fabio Ribeiro, the R. Norris and Eleanor Shreve Professor of Chemical Engineering; W. Nicholas Delgass, the Maxine S. Nichols Emeritus Professor of Chemical Engineering; Clint Chapple, the head and distinguished professor of biochemistry; Hilkka I. Kenttamaa, professor of chemistry; and Rakesh Agrawal, the Winthrop E. Stone Distinguished Professor of Chemical Engineering.

The catalyst is expensive, and the team plans to further study efficient ways to recycle it, along with ways to scale up the entire process, Abu-Omar said.

"A biorefinery that focuses not only on ethanol, but on other products that can be made from the biomass is more efficient and profitable overall," he said. "It is possible that lignin could turn out to be more valuable than cellulose and could subsidize the production of ethanol from sustainable biomass."

The U.S. Department of Energy-funded C3Bio center is an Energy Frontier Research Center. It is part of Discovery Park's Energy Center and the Bindley Bioscience Center at Purdue.

Purdue Research Foundation has filed patent applications and launched a startup company, Spero Energy, which was founded by Abu-Omar.

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Source:  Purdue University

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Satellites measure increase of Sun's energy absorbed in the Arctic

The Arctic Ocean is absorbing more of the sun's energy in recent years as white, reflective sea ice melts and darker ocean waters are exposed. The increased darker surface area during the Arctic summer is responsible for a 5 percent increase in absorbed solar radiation since 2000.
Credit: NASA Goddard's Scientific Visualization Studio/Lori Perkins

NASA satellite instruments have observed a marked increase in solar radiation absorbed in the Arctic since the year 2000 -- a trend that aligns with the steady decrease in Arctic sea ice during the same period.

While sea ice is mostly white and reflects the sun's rays, ocean water is dark and absorbs the sun's energy at a higher rate. A decline in the region's albedo -- its reflectivity, in effect -- has been a key concern among scientists since the summer Arctic sea ice cover began shrinking in recent decades. As more of the sun's energy is absorbed by the climate system, it enhances ongoing warming in the region, which is more pronounced than anywhere else on the planet.

Since the year 2000, the rate of absorbed solar radiation in the Arctic in June, July and August has increased by five percent, said Norman Loeb, of NASA's Langley Research Center, Hampton, Virginia. The measurement is made by NASA's Clouds and the Earth's Radiant Energy System (CERES) instruments, which fly on multiple satellites.

While a five percent increase may not seem like much, consider that the rate globally has remained essentially flat during that same time. No other region on Earth shows a trend of potential long-term change.

When averaged over the entire Arctic Ocean, the increase in the rate of absorbed solar radiation is about 10 Watts per square meter. This is equivalent to an extra 10-watt light bulb shining continuously over every 10.76 square feet of Arctic Ocean for the entire summer.

Regionally, the increase is even greater, Loeb said. Areas such as the Beaufort Sea, which has experienced the some of the most pronounced decreases in sea-ice coverage, show a 50 watts per square meter increase in the rate of absorbed solar radiation.

"Advances in our understanding of Arctic climate change and the underlying processes that influence it will depend critically upon high quality observations like these from CERES," Loeb said.

As a region, the Arctic is showing more dramatic signs of climate change than any other spot on the planet. These include a warming of air temperatures at a rate two to three times greater than the rest of the planet and the loss of September sea ice extent at a rate of 13 percent per decade.

While these CERES measurements could ultimately become another of those signs of dramatic climate change, right now scientists say they have obtained the bare minimum of a data record needed to discern what's happening over the long term.

Getting data beyond 15 years will allow scientists to better assess if recent trend falls outside the realm of natural variability, said Jennifer Kay, an atmospheric scientist at the Cooperative Institute for Research and Environmental Science at the University of Colorado.

"We need long time series to detect climate change signals over the internal variability. For example, observed sea ice loss over the last 30 years cannot be explained by natural variability alone." Kay said. "Fifteen years is long, but climate is often defined as the average over 30 years -- so we are only half-way there with the CERES observations."

Kay and colleagues have also analyzed satellite observations of Arctic clouds during this same 15-year period. Kay's research shows summer cloud amounts and vertical structure are not being affected by summer sea ice loss. While surprising, the observations show that the bright sea ice surface is not automatically replaced by bright clouds. Indeed, sea ice loss, not clouds, explain the increases in absorbed solar radiation measured by CERES.

Increasing absorbed solar radiation is causing multiple changes in the sea ice cover, said Walt Meier, a sea ice scientist from NASA's Goddard Space Flight Center, Greenbelt, Maryland. Two of those changes include the timing of the beginning of the melt season each year and the loss of older, thicker sea ice.

The onset of the melt season in the high Arctic is now on average seven days earlier than it was in 1982, Meier said. Earlier melting can lead to increased solar radiation absorption. This is one step in a potential feedback cycle of warming leading to melting, melting leading to increased solar radiation absorption, and increased absorption leading to enhanced warming.

Since 2000, the Arctic has lost 1.4 million square kilometers (541,000 square miles) of older ice that is more than 3 meters thick, which during winter has essentially been replaced by ice that is less than 2 meters thick, according to data provided by Mark Tschudi at the University of Colorado. Once again, Meier said, this trend is a step in a feedback cycle.

"Having younger and thus thinner ice during winter makes the system more vulnerable to ice loss during the summer melt season," Meier said.

CERES instruments are currently flying on the Terra, Aqua and Suomi-NPP satellites. The Terra satellite launched Dec. 18, 1999, and CERES first started collecting Arctic data in 2000 so 2015 will mark 15 continuous years of CERES measurements over the Arctic.

The instruments include three radiometers -- one measuring solar radiation reflected by Earth (shortwave), one measuring thermal infrared radiation emitted by Earth (longwave), and one measuring all outgoing radiation, whether emitted or reflected.

Source:  NASA/Goddard Space Flight Center

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