News and Updates

04/26/2012

High-resolution photos of lava flows on Mars reveal coiling spiral patterns that resemble snail or nautilus shells. Such patterns have been found in a few locations on Earth, but never before on Mars. The discovery, made by Arizona State University graduate student Andrew Ryan, is announced in a paper published April 27, 2012, in the scientific journal Science.

The new result came out of research into possible interactions of lava flows and floods of water in the Elysium volcanic province of Mars.

"I was interested in Martian outflow channels and was particularly intrigued by Athabasca Valles and Cerberus Palus, both part of Elysium," says Ryan, who is in his first year as a graduate student in ASU's School of Earth and Space Exploration, part of the College of Liberal Arts and Sciences. Philip Christensen, Regents' Professor of Geological Sciences at ASU, is second author on the paper.

"Athabasca Valles has a very interesting history," Ryan says. "There's an extensive literature on the area, as well as an intriguing combination of seemingly fluvial and volcanic features." Among the features are large slabs or plates that resemble broken floes of pack ice in the Arctic Ocean on Earth. In the past, a few scientists have argued that the plates in Elysium are in fact underlain by water ice.

Looking below

Assessing those claims that ice was present today beneath the lava plates drove Ryan to study the area. "My initial goal," he says, "was to model the nighttime infrared temperatures of the plates. Then I became fascinated by the terrain lying between the plates and the high-centered polygonal patterns found there." This led him to look closely at every available image of the region.

"I examined probably 100 HiRISE images of the area," he says, referring to the High Resolution Imaging Science Experiment camera on the Mars Reconnaissance Orbiter. In addition, he pored over daytime and nighttime infrared and visual images from the Thermal Emission Imaging System (THEMIS) camera on Mars Odyssey orbiter. (Christensen is THEMIS' principal investigator.) Images taken by the Context Camera (CTX) on Mars Reconnaissance Orbiter, the High Resolution Stereo Camera (HRSC) on Mars Express, and the Mars Orbiter Camera (MOC) on Mars Global Surveyor were all studied as well.

Picture this

"One evening," Ryan recounts, "I was making a second pass over the HiRISE images when I first noticed puzzling spiral patterns in an image near the southern margin of Cerberus Palus. I actually nearly overlooked that particular frame, thinking that it might not be too useful, being so far away from main study area farther north."

He notes, "The coils become noticeable in the full-resolution HiRISE image only when you really zoom in. They also tend to blend in with the rest of the light-gray terrain – that is, until you stretch the contrast a bit.

"I don't find it surprising that these were overlooked in the past. I nearly missed them too."

Curling lava

On Earth, lava coils can be found on the Big Island of Hawaii, mainly on the surface of ropey pahoehoe lava flows. They have also been seen in submarine lava flows near the Galapagos Rift on the Pacific Ocean floor.

As Ryan explains, "The coils form on flows where there's a shear stress – where flows move past each other at different speeds or in different directions. Pieces of rubbery and plastic lava crust can either be peeled away and physically coiled up – or wrinkles in the lava's thin crust can be twisted around."

Similarly, he notes that scientists have documented the formation of rotated pieces of oceanic crust at mid-ocean ridge spreading centers. "Since the surface of active lava lakes, such as those on Hawaii, can have crustal acti

vity like spreading centers do, it's conceivable that lava coils may form there in a similar way, but at a smaller scale."

The size of Martian lava coils came as a surprise. "On Mars the largest lava coil is 30 meters across – that's 100 feet. That's bigger than any known lava coils on Earth," he says. Ryan and Christensen's work has inventoried nearly 200 lava coils in the Cerberus Palus region alone.

Looking ahead, Ryan says, "Lava coils may be present in other Martian volcanic provinces or in outflow channels mantled by volcanic features. I expect that we'll find quite a few more in Elysium as the HiRISE image coverage grows over time."

 

Caption: Cooling lava on Mars can form patterns like snail shells when the lava is pulled in two directions at once. Such patterns, rare on Earth, have never before been seen on Mars. This image, with more than a dozen lava coils visible, shows an area in a volcanic region named Cerberus Palus that is about 500 meters (1640 feet) wide. Photo by: NASA/JPL-Caltech/UA

(Robert Burnham)

04/24/2012

New study reveals dark patches on Mars are weathered glass deposits

If you look at a map of Mars, you will see a mosaic of dark patches and lighter spots covering the planet. The various shades represent different sediments, but the exact composition of those sediments is something scientists are still trying to figure out. As a result of a study conducted by researchers at Arizona State University, scientists are one step closer to understanding the geology of the red planet.

In a study published in the journal Geology, School of Earth and Space Exploration (SESE) Professor Jim Bell and SESE Exploration Postdoctoral Fellow Briony Horgan report that the Martian northern lowlands are largely composed of chemically weathered glass.

Horgan and Bell began their research by collecting spectra data from the OMEGA imaging spectrometer on board the European Mars Express spacecraft. Because Mars Express is in an elliptical orbit, the spacecraft makes close passes over different areas of Mars, producing images from different times and elevations. The team used those images to produce a single map of the northern lowlands, and incorporated spectral data into that map. Translating spectral data, often represented in graphs, onto images made the spectra easier to analyze.

Once the team had the spectra mapped, they began to investigate the iron mineralogy of the sediments. The researchers found that the spectra they were observing had signatures that were consistent with a glass-rich composition.

“Glass is iron bearing, and it looks a lot like olivine and pyroxene, but it’s different enough that we can tell it apart,” explained Horgan. “When we started mapping this stuff out, we found that basically all of Acidalia Planitia, most of the north polar sand sea, and all of Utopia Planitia had that same glass signature. In total, that’s over ten million square kilometers of glassy surfaces.”

Based on lab studies, the team was able to determine that glass content of the sediments was approximately 80 to 90 percent.

“We hadn’t conclusively detected glass before on Mars,” said Horgan. “People had inferred that it must be there, since impacts and volcanoes create glass, but nobody had actually directly identified it before. So that begged the question—where did this stuff come from?”

Meteorite impacts can create glass, but usually not in the high concentrations that Horgan and Bell observed. Volcanoes, however, have the potential to create extremely large quantities of glass, especially explosive volcanoes that interact with ice and water.

Horgan and Bell used Iceland, a location where explosive volcanoes are common, as an analog to hypothesize about the conditions that could have produced the Martian glass they found.

Volcanoes in Iceland erupt underneath glaciers, and the interactions between water from the glaciers and lava from the volcanoes create incredibly explosive eruptions. The lava fragments, and transforms into particles of glass. Huge sand dunes and sand plain fields form that consist of 50 to 70 percent glass. Horgan and Bell hypothesize that the same process occurred during periods of volcanism on Mars.

This possibility presents an interesting new idea of Martian geologic history. Previously, mineral mapping evidence has been interpreted to indicate that most volcanism on Mars has been effusive (dominated by lava flows). These findings support the idea that explosive volcanism was also important in the planet's past, perhaps more important than previously thought.

Another intriguing finding is that the glass Horgan and Bell observed has been chemically weathered.

“When we see these glassy spectra, we also see a spectral signature that’s consistent with what happens when you expose glass to acid,” explained Horgan. “What that means is that these huge deposits are not only unique in that they indicate explosive volcanism, they also have experienced interactions with water.”

The northern lowlands were formed in the Amazonian epoch, the current and most recent geologic epoch on Mars. Scientists think of this epoch, which has lasted for approximately three billion years, as a very dry era, dominated by ice and snow. Horgan and Bell suggest that the chemical weathering observed on the glass is a result of melt from ice and snow during this epoch.

One question that begs further investigation is the exact nature of the glass deposits. Researchers are unsure of whether the northern lowlands are covered in a thick deposit of glass, or just a thin layer. The team also wants to see if sand dunes in other areas of Mars also exhibit these same glassy signatures. This could provide more support for the hypothesis of explosive volcanism on Mars.

Currently, the team at ASU is working on extending its map of Mars to cover the entire planet in order to explore some of the new avenues of research this study opens.

“The best you can do sometimes is to put these questions out there and intrigue your colleagues to get them to poke into it a little more,” said Bell. “And we’ll do some of that poking ourselves. There’s the whole rest of the planet to map.”

 

Caption: Dusty, glass-rich sand dunes in Siton Undae, just south of the north polar cap.

(Victoria Miluch)
 

04/03/2012

On February 29, 2012, a ceremony was held to dedicate the new Southwestern Center for Aberration Corrected Electron Microscopy, the most recent addition to the LeRoy-Eyring Center for Solid State Science’s facilities.

The microscopes housed in the new center include a JEOL ARM200F STEM, a
Nion UltraSTEM with Monochromator, and a JEOL 2010 TEM/STEM. These advanced tools have applications that range from physics to geology to life sciences.

Professor Ray Carpenter, who secured a National Science Foundation grant of more than 5 million dollars to purchase the JEOL ARM200F and the Nion UltraSTEM, spoke about the progression of the building’s construction at the ceremony. The project germinated six years ago, beginning a process of proposals, plans, design, and construction. The building itself took three months to design and six months to build, and represents one of the most advanced microscopy facilities in the nation.

“The only other comparable tools are in national labs,” said SESE Professor Tom Sharp, director of the LeRoy-Eyring Center for Solid State Science.

Because the facility is housed on an urban campus and in Arizona’s challenging environment, designers needed to take special measures to ensure the building’s stability. The sensitivity of the facility’s tools requires a very specific environment of no noise or vibrations, no electromagnetic fields as well as a constant temperature. The building was designed specifically to accommodate these conditions.

The center is an open facility for anyone on ASU’s campus, other institutions, as well as outside industry. ASU’s state-of-the-art facilities not only help expand faculty’s research capabilities, but provide others in academia and members of industry with vital services for creating developments in materials science.

Aberration correction of the electron beam results in a very small (~ 1Å) beam with sufficient intensity to allow scientists to simultaneously collect images of structure and chemical composition at the atomic scale. This is important for understanding structure and bonding in materials and at crystal imperfections that are important in the physical properties of materials. Aberration correction also allows scientists to bypass certain limitations. In traditional electron microscopes, high-resolution images are obtained by using very high accelerating voltages, but some materials cannot stand up to such voltages. Because the center’s new microscopes’ resolutions do not depend on energy, sensitive materials no longer pose a problem. Atomic resolution images can be obtained with relatively low accelerating voltages.

“It represents a very significant advance in our ability to solve many problems in materials and solid-state science,” said Sharp.

The dedication ceremony included speeches from Sethuraman Panchananthan, senior vice president of the Office of Knowledge Enterprise Development; Michael Crow, ASU president; and professors Sharp and Carpenter. Members of industry and others were invited for tours of the new microscopy building after the dedication.

“This is a landmark event that not only celebrates the future, but the past as well,” said Panchanathan at the building’s dedication ceremony.

The Leroy-Eyring Center for Solid State Science was established by the Board of Regents in 1974, and has been providing academia and industry with state-of-the-art analytical facilities and services for decades. Today, the center includes over 50 different instruments, and has more than 200 different users. The center’s new addition promises to expand the potential for research even further.

Watch video

(Victoria Miluch)

Photo by Tom Story
 

03/29/2012

Lawrence Krauss has spent much of his lifetime trying to solve the riddles nature has put before us. He also spends a lot of his time communicating the complexities of nature and its hidden beauty to a wider public.

Those latter efforts have earned Krauss, who is a Foundation Professor in ASU's School of Earth and Space Exploration and the Department of Physics, the 2012 Public Service Award from the National Science Board. The NSB is the 25-member policymaking body for the National Science Foundation and advisory body to the President and Congress on science and engineering issues.

The NSB Public Service Award honors individuals and groups that have made substantial contributions to increasing public understanding of science and engineering in the United States. Previous winners include Alan Alda, host of Scientific American Frontiers; Ira Flatow, host of National Public Radio’s Science Friday; and Craig Barrett, chairman of Intel Corp.

Throughout his career, Krauss, a renowned theoretical physicist, has taken elements of popular culture and used them as starting points to convey scientific ideas and turn on in individuals the desire to know more.

To that end, he has written several best-selling books, lectures extensively, writes for national newspapers and magazines, appears on radio and television, and convenes meetings with leading intellectuals talking physics, cosmology, nuclear security, social psychology, creativity, our place in the universe and why we (and the universe) even exist at all. He has been hailed by Scientific American as a rare “public intellectual.”

“Lawrence Krauss’ broad public outreach bridges science and popular culture through various media and intellectual pursuits, and we are proud to name him as the recipient of the 2012 NSB Public Service Award presented to an individual,” said Ray Bowen, NSB chairman.

“I am humbled and honored to receive this remarkable national award from the National Science Board,” Krauss said. “I will count this as one of the highest honors I have received. Science is the greatest intellectual adventure that I can imagine, and it involves some of the most exciting and awe-inspiring discoveries and ideas that humans have come up with, which is why I am so excited to be part of the enterprise.”

“I believe we owe it to the public to share these ideas more broadly,” he added. “Most people are actually fascinated by science once they realize that the questions they have always asked themselves really are scientific questions. This is what I have tried to encourage. And in the 21st century, we need to encourage greater scientific literacy among the public and among our political leaders if we are to address the numerous global challenges we face.”

Krauss has authored more than 300 scientific publications and nine books, including the international bestseller "The Physics of Star Trek," an entertaining and eye-opening tour of the Star Trek universe, and "Beyond Star Trek," which responds to recent exciting discoveries in physics and astronomy and takes a look how the laws of physics relate to notions from popular culture. A recent book on physicist Richard Feynman, "Quantum Man," was awarded the 2011 Book of the Year by Physics World magazine in the UK.

His most recent bestseller, "A Universe from Nothing," offers provocative, revelatory answers to the most basic philosophical questions of existence. It was on the New York Times Best Sellers list for nonfiction within a week of its release.

In addition to being a professor at ASU, Krauss is the director of the Origins Project, which explores key questions about our origins, who we are and where we came from, and then holds open forums to encourage public participation.

Krauss has been a frequent commentator and columnist for newspapers such as the New York Times and the Wall Street Journal. He has written regular columns for New Scientist and Scientific American, and appears routinely on radio and television.

He continues to be a leader in his field as he serves as a co-chair of the board of sponsors of the Bulletin of the Atomic Scientists, on the board of directors of the Federation of American Scientists, and is one of the founders of ScienceDebate2012.

Additionally, he performed solo with the Cleveland Orchestra, narrating Gustav Holst's "The Planets" at the Blossom Music Center for the most highly attended concert at that venue. Krauss also received a Grammy nomination for his liner notes for a Telarc CD of music from "Star Trek" and served as a judge at the Sundance Film Festival.

Krauss is internationally known for his work in theoretical physics – he is the only physicist to receive major awards from all three U.S. physics societies: the American Physical Society, the American Institute of Physics and the American Association of Physics Teachers.

Krauss will receive the NSB Public Service Award for an individual medal and certificate at an awards ceremony and dinner on May 3 at the U.S. Department of State in Washington, D.C. Other honorees will include the recipients of the Vannevar Bush Award, the NSB Public Service Award for a group and National Science Foundation's Alan T. Waterman Award.

 

(Skip Derra)

03/21/2012

In January 2012, the NASA Johnson Space Center and the School of Earth and Space Exploration unveiled the Project Gemini Online Digital Archive. Project Gemini (1964-1966) was the second United States human spaceflight program, after Project Mercury (1960-1963). The Gemini astronauts took some of the most memorable photos in NASA history and a team of scientists led by Professor Mark Robinson brought these historic flights to life by making high-resolution scans of the original flight films.

A special multimedia package in Air & Space Mag.com by Tony Reichhardt commemorates Project Gemini with a gallery of select images from the archive. You can read the story and view the photos here: http://www.airspacemag.com/multimedia/Ghosts-of-Gemini.html?c=y&page=1&n...

Visit the March to the Moon gallery for the full collection, complete with high-resolution, downloadable versions.

 

Image: Ed White, the first American to walk in space, photographed by Jim McDivitt during the Gemini IV mission [NASA/JSC/Arizona State University].
 

03/19/2012

Geologic map of Jupiter’s moon Io details an otherworldly volcanic surface

More than 400 years after Galileo’s discovery of Io, the innermost of Jupiter’s largest moons, a team of scientists led by Arizona State University (ASU) has produced the first complete global geologic map of the Jovian satellite. The map, published by the U. S. Geological Survey, depicts the characteristics and relative ages of some of the most geologically unique and active volcanoes and lava flows ever documented in the Solar System.

Following its discovery by Galileo in January 1610, Io has been the focus of repeated telescopic and satellite scientific observation. These studies have shown that the orbital and gravitational relationships between Io, its sister moons Europa and Ganymede, and Jupiter cause massive, rapid flexing of its rocky crust. These tidal flexures generate tremendous heat within Io’s interior, which is released through the many surface volcanoes observed.

“One of the reasons for making this map was to create a tool for continuing scientific studies of Io, and a tool for target planning of Io observations on future missions to the Jupiter system,” says David Williams, a faculty research associate in the School of Earth and Space Exploration at ASU, who led the six-year research project to produce the geologic map.

The highly detailed, colorful map reveals a number of volcanic features, including: paterae (caldera-like depressions), lava flow fields, tholi (volcanic domes), and plume deposits, in various shapes, sizes and colors, as well as high mountains and large expanses of sulfur- and sulfur dioxide-rich plains. The mapping identified 425 paterae, or individual volcanic centers. One feature you will not see on the geologic map is impact craters.

“Io has no impact craters; it is the only object in the Solar System where we have not seen any impact craters, testifying to Io’s very active volcanic resurfacing,” says Williams.

Io is extremely active, with literally hundreds of volcanic sources on its surface. Interestingly, although Io is so volcanically active, more than 25 times more volcanically active than Earth, most of the long-term surface changes resulting from volcanism are restricted to less than 15 percent of the surface, mostly in the form of changes in lava flow fields or within paterae.

“Our mapping has determined that most of the active hot spots occur in paterae, which cover less than 3 percent of Io’s surface. Lava flow fields cover approximately 28 percent of the surface, but contain only 31 percent of hot spots,” says Williams. “Understanding the geographical distribution of these features and hot spots, as identified through this map, are enabling better models of Io’s interior processes to be developed.”

The Io geologic map is unique from other USGS-published planetary geologic maps because surface features were mapped and characterized using four distinct global image mosaics. These image mosaics, produced by the USGS, combine the best images from NASA’s Voyager 1 and 2 missions (acquired in 1979) as well as the Galileo orbiter (1995-2003).

Using the mosaics from the USGS, Williams mapped the entire surface of Io into 19 different types of surface material types, and determined their locations and sizes (areas). He then correlated the map information with the locations of all known hot spots (locations of active volcanism) to provide a global picture of the styles of volcanism on Io.

“Because of the non-uniform coverage of Io by multiple Voyager and Galileo flybys, including a variety of lighting conditions, it was absolutely necessary to use the different mosaics to identify specific geologic features, such as separating mountains and paterae from plains, and separating the colored plume deposits from the underlying geologic units,” says Williams.

Though the geology history of Io has been studied in detail for several decades, completion of the geologic map establishes a critical framework for integrating and comparing diverse studies.

“Planetary geologic mapping inevitably drives scientific progress,” says Ken Herkenhoff, USGS Astrogeology Acting Science Center director. “Mapping the geology of a planetary surface [such as Io] forces scientists to carefully consider hypotheses that address the geologic evolution of an entire planet and test these hypotheses against all available observations.”

“Because Io is so active, and continues to be studied by Earth-based telescopes, we are doing something different than producing just the paper geologic map,” says Williams. “We are also making an online Io database, to include the geologic map, the USGS mosaics, and all useful Galileo spacecraft observations of Io. This database, when completed later this year, will allow users to track the history of surface changes due to volcanic activity. We also have proposals submitted to NASA to include in our Io database Earth-based telescopic observations and images from the February 2007 NASA New Horizons spacecraft flyby, to create a single online source to study the history of Io volcanism.”

The project was funded by the National Aeronautics and Space Administration through its Outer Planets Research and Planetary Geology and Geophysics Programs. Technical and editorial support for map production was provided by the USGS Astrogeology Science Center in Flagstaff, Ariz.

The geologic map can be downloaded from the USGS here: http://pubs.usgs.gov/sim/3168

(Nikki Cassis)
 

03/15/2012

Experimental cosmologist Judd Bowman has been awarded a NASA Nancy Grace Roman Technology Fellowship in Astrophysics for early-career researchers. He is one of three recipients to receive this prestigious new award.

Bowman is an assistant professor in the School of Earth and Space Exploration at Arizona State University. He is an interested in the formation of structure in the early Universe, including the first stars, galaxies, and black holes.

Last fall, NASA established the Roman Technology Fellowship program to foster technologies that advance scientific investigations in the origin and physics of the universe and future exoplanet exploration. The fellowship is named after Nancy Grace Roman, a distinguished American astronomer who was instrumental in establishing the new era of space-based astronomical instrumentation. The award will support Bowman and a postdoc for a one-year concept study, with the opportunity to continue on for a three-year instrument development program.

This fellowship is well-suited to Bowman’s research interests, which focus on the development of technologies to enable observational probes of Cosmic Dawn, the period when the first stars, galaxies, and black holes are believed to have formed only a few hundred million years after the Big Bang.

“Learning how and when stars and galaxies first formed in the early Universe is central to understanding our place in the Universe today, yet it is very challenging. The first galaxies will be very difficult to see with telescopes so we are trying a different approach,” explains Bowman.

The project that Bowman proposed is to identify the best wideband radio receiver design at low radio frequencies.

“Low-frequency radio observation of the redshifted 21 cm line of neutral hydrogen is a promising technique to study the gas around the first galaxies, but we need to build radio receivers that we can calibrate 100 times better the best radio receiver used by astronomers today. That is a difficult task! We have only just begun to attempt it,” says Bowman. “The Roman Technology Fellowship will hopefully give us the jump start we need to make this technology a reality.”

Bowman and collaborators have already designed a prototype and will be traveling to Australia over spring break to test it. Stay current on the latest developments by reading posts at: http://asuexplorers.wordpress.com

“This project very much epitomizes what SESE stands for – the melding of science and technology to promote exploration of our Universe and environment. We are pushing technological limits in ways that will likely benefit earth, atmospheric, and planetary science, as well as astronomy. In order to even get to this point, we've had to revisit and extend core equations used in electrical engineering that have been well established for over 30 years,” says Bowman.

The receiver Bowman and his collaborators will develop is part of a NASA mission concept called DARE (Dark Ages Radio Explorer) that would orbit the Moon, using the Moon as a shield to block disruptive transmissions, such as FM radio and TV stations, originating from the earth.

“We will work closely with our collaborators on DARE at JPL, University of Colorado, and the National Radio Astronomy Observatory. In particular, this fellowship will help to strengthen ties between ASU and JPL and provide opportunities for students to visit JPL and JPL scientists to come to ASU to work with students in our lab here,” says Bowman.

Bowman is principal investigator of EDGES, a ground-based pathfinder for the DARE mission concept, and is project scientist for the Murchison Widefield Array. Bowman also co-leads the DARE Calibration and Instrument Validation team and is a co-investigator of the Lunar University Network for Astrophysics Research.

(Nikki Cassis)
 

03/14/2012

Again this summer, in collaboration with the American Geosciences Institute (AGI) and NASA, the School of Earth and Space Exploration is hosting a week-long Earth and Space Science Teacher Leadership Academy. Successful applicants will receive training in current NASA research and other hot topics in Earth and space sciences, abundant teaching resources, continuing education credit, and a stipend. The application deadline is Monday 30 April. Please refer to the posted flyer for details.

03/13/2012

Mihály Pósfai, a member of the Hungarian Academy of Sciences (HAS) , arrived in Tempe last week and will be in residence as an ASU Visiting Professor during March doing microscopy research. 

In 2010, Pósfai, a former ASU scientist, was elected a member of the HAS, an organization of scientific notables that has had a long and distinguished membership reflecting the rich and fruitful scientific traditions of Hungary. Election to a National Academy of Sciences is one of the highest honors bestowed on scientists in their respective countries.

The HAS has 365 members. New members are elected every three years through an elaborate election process. An interesting rule is that the number of members younger than 70 cannot exceed 200 (Posfai is 49). Pósfai reports that a noteable consequence of being a member is that some people laugh significantly louder when you tell a joke than they used to.

Pósfai was a postdoctoral research associate at ASU from 1992 to 1994 and again from 1996 to 1998 in the 7*M research group of Professor Peter Buseck in the then Departments of Geology and Chemistry. Since leaving ASU he has been on the faculty and is currently professor in the Department of Earth and Environmental Sciences, University of Pannonia, a relatively new university in Hungary.

While at ASU, he started his dual areas of research acclaim: a) Characterization of individual species in atmospheric aerosol particles to understand their formation and transport and to learn about their role in atmospheric processes and in global climate change, and b) Biologically controlled mineralization in magnetotactic bacteria, and synthesis and characterization of the physical and chemical properties of nanoparticles of iron sulfides and iron oxides.

”It is great to be back at ASU. I arrived here for the first time exactly 20 years ago as a postdoc. The campus has impressively expanded since then but it still feels like home, with many familiar faces and a vibrant atmosphere,” says Pósfai. ”The first week was spent by settling in, getting a glimpse of the wonderful new electron microscopes, and starting on new projects in environmental mineralogy.”

During his month on campus, Pósfai will be working on both atmospheric chemistry problems, primarily on whether or not the structural variations in soot are related to its bulk properties such as toxicity. He will also be looking at biominerals; a new project is underway to better understand the role of algae in the precipitation of calcite from lakewater.

Pósfai and Buseck have had a continuing collaboration through the years. They most recently had a paper on ”Nature and climate effects of tropospheric aerosol particles” appear in the 2010 Annual Review of Earth and Planetary Sciences. In 1998 two of their papers were published in Science about electron microscopy of bacteria that contain magnetic nanocrystals. One of those was co-authored with ASU researchers R. Dunin-Borkowski and M. McCartney of the Department of Physics.

The election of Pósfai is an honor both to his home institution and to ASU, which helped foster the creativity of this celebrated and relatively young scientist.

 

(Nikki Cassis)
 

03/05/2012

Biogeochemist’s research on Biological Soil Crusts shows link between geology and biology

Biological soil crusts (BSCs) are complex communities of organisms, including cyanobacteria (commonly known as blue-green algae), mosses, lichens, and fungi that occupy arid and semi-arid regions challenging to higher life forms. To the untrained eye, they resemble dry, dusty clumps of soil and moss, but BSCs are a vital link between sterile land and flourishing ecosystems. BSCs convert essential elements like nitrogen and carbon into bioavailable forms, they decrease water runoff, and increase water retention. In essence, they increase the habitability of their environments.

Katie Noonan, a SESE PhD student in biogeochemistry, studies BSCs in Moab, Utah. Noonan has been interested in the intersection between geology and biology since her undergraduate years at the University of California, Davis. “I have always been fascinated by the relationship between the fields [of geology and biology],” says Noonan, “And so I’ve always been interested in research that bridges the two. After beginning my graduate career at ASU I recognized that chemistry provides the direct link between geology and biology and so I decided I wanted a project that had aspects of all three fields.”

Noonan was attracted to ASU’s geology program because of its emphasis on interdisciplinary research. “The interdisciplinary attitude of my advisor and committee has made my research project possible,” she says. “My project has aspects of microbiology, ecology, geochemistry, biochemistry, soil science, and mineralogy. Noonan’s project is funded by a National Science Foundation Biogeosciences grant to SESE faculty members Hilairy Hartnett, an organic geochemist, and Ariel Anbar, a trace-metal geochemist. Ferran Garcia-Pichel, a geomicrobiologist, from the School of Life Sciences is also a collaborator on the project. Without the support of researchers across these fields I would not have been able to include such a diverse array of topics in my dissertation.”

Noonan’s thesis explores this chemical linking between geology and biology. BSC communities need a variety of metals to perform their biological functions, such as photosynthesis and nitrogen fixing, but these metals are often insoluble in the arid environments in which the crusts form. Somehow, the BSC organisms must be able to extract the metals from their environment; they could not otherwise survive.

Noonan hypothesized that BSC microbes produce small organic compounds called siderophores that bind metals in their environment, releasing them from minerals and making them available for microbial uptake. Siderophores therefore act as chemical weathering agents: they chemically break down rocks and minerals to their constituent elements, directly linking microbes in the BSCs to the minerals on which they rely.

To test her hypothesis, Noonan collected BSC samples from her field site near Moab. She used a biochemical assay to screen for siderophore-producing microbes, then isolated and cultured these organisms, and used gene sequencing to identify them. Her results were exciting: 70% of the organisms she screened turned out to produce siderophores, and she found five novel siderophores-producing organisms in her samples. Her results, combined with those of previous research, indicate that siderophores-producing organisms account for some of the dominant BSC microbes.

This is the first time siderophore production has been reported in BSCs, and it adds immeasurably to our understanding of how metals are cycled through arid ecosystems. The work also has much broader implications, from astrobiology to land conservation. “BSCs live in an extreme environment characterized by intense UV radiation, low water availability, and drastic fluctuations in temperature,” says Noonan. These conditions
are similar to those under which life on Earth evolved. “BSCs are adapted to withstand these conditions,” she continues, “so understanding how they evolved and how they function is important for understanding the development of terrestrial ecosystems on Earth and can also be applied to potential life on other planets.” This project was also funded in part by the ASU NASA Astrobiology Institute.

“BSCs are crucial members of their ecosystems because they provide the primary source of bioavailable carbon and nitrogen, increase soil stability and water retention, and influence the bioavailability of trace metals,” says Noonan. The soil crusts are
fragile, though, and are easily disturbed by livestock grazing or vehicle traffic. “When these activities destroy BSCs it takes them decades to recover,” says Noonan. “[That] causes the ecosystem to suffer and can lead to desertification.” Her study will help conservationists understand how to increase the growth in BSC communities, and decrease damage to them from anthropogenic activities.

In December, Noonan presented her research at the annual meeting of the American Geophysical Union (AGU) in San Francisco, CA. Along with approximately
20,000 professionals, students, professors, and policy makers, she attended other presentations, talked about her own work, and met with friends and colleagues. Noonan enjoys and values AGU as a venue to share her work.

“AGU is a very interdisciplinary venue with presentations on a variety of topics,” she says. “Because so many people attend the conference it is an excellent opportunity to reconnect with old colleagues and catch up on the work everyone is doing. There are always sessions that are directly related to my work, but also sessions that give me new ideas and fresh motivation.”

(Alice Letcher)

 

Caption: Katie Noonan holds a culture of a cyanobacterium she isolated from the crust, which is one of the nine organisms she isolated that produce
siderophores, small organic compounds that microbes make to increase iron bioavailability. Credit: Patrick Scott Noonan