OREGON STATE UNIVERSITY

scientific research and advances

Scientists name new species of fish from the Orinoco region after singer Enya

CORVALLIS, Ore. – In 1988, Irish singer and songwriter Enya released a lead single titled “Orinoco Flow” from her second studio album, which went on to become an international hit, earn a Grammy Award nomination, and help launch her wildly successful career.

Now a team of scientists have named a new species of fish from the Orinoco River drainage after her.

Leporinus enyae is a “beautiful little fish,” said Michael Burns, a doctoral candidate at Oregon State University and lead author on the paper describing the new species, as well another from the Xingu River of Brazil. It was published this week in the journal Neotropical Ichthyology by researchers from Oregon State and Brazil.

“Whenever we were in the lab at Oregon State working on the fishes, Ben Frable would always play ‘Orinoco Flow,” said Burns, referring to another graduate student in the lab.

“I heard the song so often in the lab it got stuck in my head,” co-author Marcus Chatfield said. “Then I just started listening to it on purpose when I was taking measurements of the specimens. When the time came around for choosing names, it just felt right to name this new beautiful fish from the Orinoco after the artist who wrote that beautiful song.”

“We’re also big fans of her music,” added co-author Brian Sidlauskas, the curator of fishes at Oregon State University as well as an amateur Celtic harper.

The second newly discovered fish has been named Leporinus villasboasorum, in honor of the pioneering efforts of brothers Orlando, Cláudio and Leonardo Villas-Bôas a half-century ago to protect the Xingu River’s biodiversity and the rights of indigenous peoples there.

Leporinus is the largest and most diverse genus in the characiform family Anostomidae and includes roughly 90 species across most of South America. New species are described yearly and the genus includes many “poorly understood” species complexes, according to Sidlauskas.

“We thought it would be fairly straightforward to look at populations of similar fishes from the Orinoco River basin in Venezuela, the Essequibo River of Guyana, and several of the tributaries of the Amazon River in Brazil and see if they are taxonomically the same or different,” Sidlauskas said. “It turns out that there are at least two new distinct species, and there may be more.”

Both new species are comparatively small – about 8 to 10 inches long – although some members of their family can reach two feet in length. Smaller species are sold as aquarium fish, though in the wild, these omnivores prefer moving water – both for feeding and protection from predators.

The term Leporinus literally means “little hare,” in reference to the large teeth that protrude from the mouth, much like those of a rabbit. The bottom teeth of the two new species are particularly long, and while no one is sure why, the researchers note that it may relate to their foraging on plants, worms and other invertebrates.

It isn’t unusual to discover new fish species, especially in the tropical river basins of South America, the scientists say. The region is vast and the network of rivers and tributaries flows through many different types of terrain and microhabitats, leading to speciation on a fine scale.

To an outsider, the new fish species are not remarkably different from two previously established species, Leporinus desmotes and Leporinus jatuncochi. However, there are significant differences in body shape, coloration, scale counts and genetics, Burns said.

“The differences and divergence between the two new Leporinus species and the established ones may trace back several million years,” Sidlauskas said.

“Preserving these different lineages may be very important because one species may have developed evolutionary traits that the others don’t have,” Burns added.

Sidlauskas said Brazil has recently built the Belo Monte Dam on the Xingu River inside the range of the newly discovered Leporinus villasboasorum. Belo Monte is the fourth-largest dam in the world and has the potential to significantly alter habitats on a huge scale. Such anthropogenic influences can threaten fish species that are geographically distinct and limited in range. The impact of the Belo Monte Dam on the recently named Leporinus villasboasorum has yet to be evaluated.

“There also is a lot of local influence on these major rivers and, in turn, the fish species,” Sidlauskas said.

The study was funded by the National Science Foundation, Fundação Araucária (Brazil) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brazil). Co-author on the study was José Birindelli of Universidade Estadual de Londrina in Brazil. The OSU authors are all affiliated with the Department of Fisheries and Wildlife in the College of Agricultural Sciences. Fish in the study were provided by 28 collections in the United States, South America, Europe and Canada.

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Leporinus enyae

Diatoms have sex after all, and ammonium puts them in the mood

CORVALLIS, Ore. – New research shows a species of diatom, a single-celled algae, thought to be asexual does reproduce sexually, and scientists learned it’s a common compound – ammonium – that puts the ubiquitous organism in the mood.

The findings, published today in PLOS One, may be a key step toward greater understanding of the evolution of sexual behavior and also have important biotechnology implications.

“Our discoveries solve two persistent mysteries that have plagued diatom researchers,” said corresponding author Kimberly Halsey, a microbiologist at Oregon State University. “Yes, they have sex, and yes, we can make them do it.”

Diatoms hold great potential as a bioenergy source and also for biosensing. In addition, their intricate, silica cell walls offer promising nanotechnology applications for materials chemists and drug-delivery researchers.

There are more than 200,000 species of diatoms, and the organisms are abundant nearly everywhere water is found, forming huge blooms in the spring and fall that help drive the marine carbon cycle.

“Diatoms are amazing; their silica frustules are beautiful and exquisite,” Halsey said. “Now that we can control their sexual pathway, that should open the door to being able to make crosses between different diatoms with different characteristics. We should be able to breed them just like we do with corn or rice or strawberries to select for traits that are really desirable.”

Halsey and collaborators in botany and statistics from OSU’s colleges of Science and Agricultural Sciences studied the “centric” Thalassiosira pseudonana species of diatom, a model organism for researchers; it’s one of two diatoms, the other being the “pennate” diatom Phaeodactulum tricornutum, to have had its genome sequenced.

Centric diatoms are radially symmetrical – think of them as shaped like a soup can, Halsey says – and pennate diatoms are bilaterally symmetrical: elongated in the manner of a pea pod.

“Everybody said Thalassiosira pseudonana was asexual, because they’d never seen anything else,” Halsey said. “The general thinking was that it just lost the ability or need to go through sex.”

Other scientists, Halsey notes, had showed T. pseudonana retained genes necessary for meiosis, a type of genetic replication specific to sexual reproduction, and concluded the diatom wasn’t using those genes.

“But we started seeing very different morphologies,” changes in cell structure, Halsey said, in this case related to sexual activity. “We also saw genes expressed that are involved in flagellar structures and assembly, which would only happen with sperm cells.”

Graduate student Eric Moore, lead author on the research, was astonished to learn “these single-celled organisms can differentiate into male and female cells, completely changing their morphologies.”

“In fact, I was convinced my cultures were contaminated before I realized what was actually going on,” he said.

Previous work by other researchers studying different types of centric diatoms showed that growth stress – interruptions of light, changes in salinity, shifts in nutrients – can sometimes, but not reliably, cause cells to become sexual.

“Lab efforts to induce sex in centric diatoms have ranged from sweet talk to torture,” Halsey said.

But manual, microscopic analysis by Halsey’s team found that ammonium, a common compound that’s a metabolic waste product of animals, reliably caused two strains of T. pseudonana and two other centric diatoms to change their cell structures, making eggs and sperm; ammonium caused the diatoms to get ready for sex when at least one other cell growth factor – such as light, phosphorus or silica – was in short supply.

In addition, RNA sequencing showed more than 1,200 diatom genes that changed in activity when ammonium lit the algae’s sexual fires. Halsey suggests that in nature, the protists that graze on the diatom blooms excrete the ammonium that triggers the diatoms’ sexualization.

“The specific collection of environmental factors that make diatoms have sex aren’t yet known,” she said. “But identifying ammonium as a sexuality inducer potentially opens the door to new avenues of research into breeding and genetic modification to control important traits.”

Collaborators also included Brianna Bullington of OSU’s Department of Microbiology, Alexandra Weisberg of the Department of Botany and Plant Pathology, and Yuan Jiang of the Department of Statistics.

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Study finds Earth’s magnetic field ‘simpler than we thought’

CORVALLIS, Ore. – Scientists have identified patterns in the Earth’s magnetic field that evolve on the order of 1,000 years, providing new insight into how the field works and adding a measure of predictability to changes in the field not previously known.

The discovery also will allow researchers to study the planet’s past with finer resolution by using this geomagnetic “fingerprint” to compare sediment cores taken from the Atlantic and Pacific oceans.

Results of the research, which was supported by the National Science Foundation, were recently published in Earth and Planetary Science Letters.

The geomagnetic field is critical to life on Earth. Without it, charged particles from the sun (the “solar wind”) would blow away the atmosphere, scientists say. The field also aids in human navigation and animal migrations in ways scientists are only beginning to understand. Centuries of human observation, as well as the geologic record, show our field changes dramatically in its strength and structure over time.

Yet in spite of its importance, many questions remain unanswered about why and how these changes occur. The simplest form of magnetic field comes from a dipole: a pair of equally and oppositely charged poles, like a bar magnet.

“We’ve known for some time that the Earth is not a perfect dipole, and we can see these imperfections in the historical record,” said Maureen “Mo” Walczak, a post-doctoral researcher at Oregon State University and lead author on the study. “We are finding that non-dipolar structures are not evanescent, unpredictable things. They are very long-lived, recurring over 10,000 years – persistent in their location throughout the Holocene.

“This is something of a Holy Grail discovery,” she added, “though it is not perfect. It is an important first step in better understanding the magnetic field, and synchronizing sediment core data at a finer scale.”

Some 800,000 years ago, a magnetic compass’ needle would have pointed south because the Earth’s magnetic field was reversed. These reversals typically happen every several hundred thousand years.

While scientists are well aware of the pattern of reversals in the Earth’s magnetic field, a secondary pattern of geomagnetic “wobble” within periods of stable polarity, known as paleomagnetic secular variation, or PSV, may be a key to understanding why some geomagnetic changes occur. 

The Earth’s magnetic field does not align perfectly with the axis of rotation, which is why “true north” differs from “magnetic north,” the researchers say. In the Northern Hemisphere this disparity in the modern field is apparently driven by regions of high geomagnetic intensity that are centered beneath North America and Asia.

“What we have not known is whether this snapshot has any longer-term meaning – and what we have found out is that it does,” said Joseph Stoner, an Oregon State University paleomagnetic specialist and co-author on the study. 

When the magnetic field is stronger beneath North America, or in the “North American Mode,” it drives steep inclinations and high intensities in the North Pacific, and low intensities in Europe with westward declinations in the North Atlantic. This is more consistent with the historical record.

The alternate “European mode” is in some ways the opposite, with shallow inclination and low intensity in North Pacific, and eastward declinations in the North Atlantic and high intensities in Europe.

“As it turns out, the magnetic field is somewhat less complicated than we thought,” Stoner said. “It is a fairly simple oscillation that appears to result from geomagnetic intensity variations at just a few recurrent locations with large spatial impacts. We’re not yet sure what drives this variation, though it is likely a combination of factors including convection of the outer core that may be biased in configuration by the lowermost mantle.”

The researchers were able to identify the pattern by studying two high-resolution sediment cores from the Gulf of Alaska that allowed them to develop a 17,400-year reconstruction of the PSV in that region. They then compared those records with sediment cores from other sites in the Pacific Ocean to capture a magnetic fingerprint, which is based on the orientation of the magnetite in the sediment, which acts as a magnetic recorder of the past.

The common magnetic signal found in the cores now covers an area spanning from Alaska to Oregon, and over to Hawaii.

“Magnetic alignment of distant environmental reconstructions using reversals in the paleomagnetic record provides insights into the past on a scale of hundreds of thousands of years,” Walczak said. “Development of the coherent PSV stratigraphy will let us look at the record on a scale possibly as short as a few centuries, compare events between ocean basins, and really get down to the nitty-gritty of how climate anomalies are propagated around the planet on a scale relevant to human society.”

The magnetic field is generated within the Earth by a fluid outer core of iron, nickel and other metals that creates electric currents, which in turn produce magnetic fields. The magnetic field is strong enough to shield the Earth from solar winds and cosmic radiation. The fact that it changes is well known; the reasons why have remained a mystery.

Now this mystery may be a little closer to being solved.

Walczak and Stoner are in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. Other authors on the study are Alan Mix, also of OSU; John Jaeger, Gillian Rosen and James Channell of the University of Florida; David Heslop of Australian National University; and Chuang Xuan of the University of Southampton.

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Special Olympians will help OSU researchers gain further health insights

CORVALLIS, Ore. – More than 2,000 athletes will descend on Corvallis on July 8 and 9, competing in the Special Olympics Oregon Summer State Games while also helping to further research into the health of people with intellectual disabilities.

“There still is this misconception that if you have a disability, then you cannot be healthy,” said Gloria Krahn, the Barbara Emily Knudson Endowed Chair in Family Policy Studies at Oregon State University. “I would’ve thought that after 25 years, we would be past some of that. Special Olympics is helping bring about that change.”

Oregon State is hosting the Summer State Games, which feature track and field, bocce, golf and softball, with events split between Corvallis High School and the OSU campus.

Special Olympics Oregon’s Healthy Athletes program will also be part of the Summer State Games, providing free health screenings for the athletes. The screenings involve six areas called Fit Feet, FUNfitness, health promotion, Healthy Hearing, Opening Eyes and Special Smiles. Strength, flexibility, balance and endurance will be tested, and athletes will be given a take-home program based on their results that aims to improve and encourage their participation in sports and recreational activities.

Special Olympics Oregon regularly hosts Healthy Athletes programs around the state.

Special Olympics Oregon also provides a program called Oregon Team Wellness for those with intellectual disabilities. The program incorporates incentives and rewards to reach benchmarks, with the ultimate goal of lifelong healthy choices and habits.

The program, which started in Oregon, has spread to other states in the Northwest. Researchers at OSU, including Alicia Dixon-Ibarra, a post-doctoral scholar in OSU’s College of Public Health and Human Sciences, and Krahn, are working with Special Olympics to evaluate the program.

Dixon-Ibarra is working on the research and practical side of the games.

She will gather information used in research designed to further improve the health of people with intellectual disabilities. All the information from the weekend will go into one of the largest data sets for people with intellectual disabilities in the world, and can show discrepancies between different countries and their health issues. One area of the world could have issues relating to tooth decay, for example, while another may have higher rates of obesity.    

“I find this job really rewarding,” Dixon-Ibarra said. “I know there’s a huge need for health care and health promotion for this population based on my own research and the research of others in my area, and that this is a big need that we’re fulfilling with these programs.”

Dixon-Ibarra said a common misconception is that people with intellectual disabilities can’t be as healthy as those without. Also, Krahn notes that until relatively recently, trying to keep a person with a disability active and healthy fell solely on the family, without much help from school districts or other groups that organize sports and other recreational activities.

Helping to change attitudes, the researchers say, are programs like the Special Olympics, founded by Eunice Kennedy Shriver in 1968. From a small beginning – just 1,000 athletes competed in the first Special Olympics World Games – the Special Olympics are now in 169 nations and encourage more than 4 million people with developmental disabilities to be active and healthy. Shriver will be posthumously honored for her work on July 12 at the 25th annual ESPYS on ABC. 

Athletes and coaches will stay in OSU residence halls during the Summer State Games. Parking is free around Reser Stadium, and admission is free to all events. The public is invited to watch the athletes compete, and a complete schedule of the events can be found here.

People interested in volunteering with the Special Olympics Oregon Summer State Games should contact LouAnne Tabada, senior director of volunteer services for Special Olympics Oregon, at Itabada@soor.org or volunteer@soor.org.    

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Lanesha Reagan, 425-359-3054

Krill hotspot fuels incredible biodiversity in Antarctic region

CORVALLIS, Ore. – There are so many Antarctic krill in the Southern Ocean that the combined mass of these tiny aquatic organisms is more than that of the world’s 7.5 billion human inhabitants.

Scientists have long known about this important zooplankton species, but they haven’t been certain why particular regions or “hotspots” in the Southern Ocean are so productive. One such hotspot exists off Anvers Island – along the western Antarctic Peninsula – where high densities of Antarctic krill episodically concentrate near the shore close to a number of Adélie penguin breeding colonies. 

As it turns out, a perfect combination of tides and wind is responsible, according to scientists who just published a study on the krill in the journal Deep Sea Research. The research was funded by the National Science Foundation.

“This region off the western Antarctic Peninsula has been a known breeding area for Adélie penguins for thousands of years,” said Kim Bernard, a biological oceanographer at Oregon State University and lead author on the study. “We know it today as a krill hotspot and it probably has been for some time.

“But despite their abundance, there is growing concern about krill not only because of climate change, but because they are now being harvested for human food, nutritional supplements and aquaculture feed. Yet historically we’ve known little about what makes this particular area so productive for krill. So we set out to learn more about it.”

Bernard and a team of colleagues spent four consecutive summer seasons in the Antarctic mapping the patterns in distribution and biomass of Antarctic krill, also known as Euphausia superba. They also sought to identify the environmental conditions responsible for the hotspot. 

What they discovered is a near-perfect system in which krill aggregations situated over the Palm Deep Canyon – a region of nutrient-rich waters that produce a lot of food for the krill – are delivered close to shore by tidal currents and winds. When the winds are westerly and the tides are diurnal – one high tide and one low tide each day – the krill biomass close to shore is at its peak and krill aggregations are huge.

“It’s neat – we can predict exactly when humpback whales will be close to shore off Palmer Station just based on the tides,” Bernard said. “When there are diurnal tides, you’ll see krill from the surface to the ocean floor – they are everywhere. And when they are, the whales are there, too.

“This concentration and transport toward shore are particularly important for the penguins that breed there. The farther they have to go to forage, the less their chicks have to eat and chick weight is a huge factor in their survival. A difference of a few hundred grams in chick weight is the difference between life and death.”

When the tides shift to semi-diurnal – two high and two low tides daily – currents move the krill away from shore and their predators follow. Likewise, a shift to southerly winds keeps the krill farther from shore and more spread out.

Antarctic krill can live five to seven years, and grow to a length of a little more than two inches. They don’t reach sexual maturity for two years, and when they reproduce, they must release their eggs in water roughly 1,000 meters (or about 3,200 feet) deep. That’s because they need a certain period of time to develop as they drift to the ocean floor, and another period of time to go through different life stages as they re-ascend to the surface.

Studies have shown that sea ice may be critical to their survival, but scientists are not exactly sure why, Bernard said.

“We see very strong correlations between krill biomass and sea ice,” she noted. “When the sea ice is low, the krill populations crash the next summer. It could be a change in algae or other food for them, or it could be that sea ice provides shelter from predators, or affects the currents in some way. We just don’t yet know.

“It would be nice to find out, because sea ice abundance may vary greatly in the future.”

Bernard is on the faculty of OSU’s College of Earth, Ocean, and Atmospheric Sciences.

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Penguins rely on close-to-shore krill

Participants sought for study on family dogs and physical activity for kids with disabilities

CORVALLIS, Ore. – Oregon State University researchers are recruiting children with disabilities and their family dogs for a research study that will test a new intervention to see if pairing the dog and the child can help the child become more physically active.

The project is led by Megan MacDonald of OSU’s College of Public Health and Human Sciences and Monique Udell of OSU’s College of Agricultural Sciences. The researchers recently received a two-year, $375,000 grant from the National Institutes of Health’s Eunice Kennedy Shriver National Institute of Child Health and Human Development to support the project.

Children with disabilities spend less time participating in physical activity compared to their peers and are considered a health disparity group, meaning they generally face more health concerns than their peers. And physical activity tends to drop among all children around age 12. The goal of the study is to see if the partnership with the family dog leads to improvements in children’s physical activity levels, which in turn could lead to other health improvements.

“We need to find creative ways to engage kids in physical activity,” MacDonald said. “And beyond physical activity, animal companionship can have a significant impact on health and well-being.” 

The new study builds on the researchers’ earlier work exploring how a family dog might serve as a partner to help a child with disabilities become more active. In a recent case study of one 10-year-old boy with cerebral palsy and his family’s dog, the researchers found the intervention program led to a wide range of improvements for the child, including physical activity as well as motor skills, quality of life and human-animal interactions. They also found that the dog’s behavior and performance on cognitive and physical tasks improved alongside the child’s.

The new intervention is aimed at children with disabilities who are 10 to 16 years old and have a family dog that also could participate in the study. The children will learn how to train their dog in new behaviors with the “Do As I Do” method, which uses positive reinforcement. “Do As I Do” is similar to the game “Simon Says,” in which the dog follows the lead of the child.

“It’s really about the child and the dog being active together as a team,” MacDonald said. “The program also could help the relationship between the child and the dog grow.”

Families will come to OSU for one hour daily for two weeks during the study, which is expected to begin later this summer. There is some flexibility to the schedule depending on families’ needs. The children also will have homework such as walking the dog each day at home. Not all families selected for the study will participate in the “Do as I Do” training this year but all families will have a chance to participate in the training over the course of the two-year study.

“Participating children need to be able to follow basic instructions but beyond that, we want to be as inclusive as possible,” MacDonald said. “Parents who have questions about whether their child and their pet are a good fit for the study should feel free to give me a call so we can discuss their individual needs.”

Families interested in learning more about the study or participating in it should contact MacDonald at 541-737-3273 or Megan.MacDonald@oregonstate.edu

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New gonorrhea treatment targets enzyme needed for respiration

CORVALLIS, Ore. – Researchers have identified a possible new treatment for gonorrhea, using a peptide that thwarts the infection-causing bacterium by interfering with an enzyme the microbe needs to respirate.

The findings are especially important since Neisseria gonorrhoeae is considered a “superbug” due to its resistance to all classes of antibiotics available for treating infections.

Gonorrhea, a sexually transmitted disease whose numbers grow by 78 million new cases worldwide each year, is highly damaging to reproductive and neonatal health if untreated or improperly treated.

It can lead to endometritis, pelvic inflammatory disease, ectopic pregnancy, epididymitis and infertility. And babies born to infected mothers are at increased risk of blindness.

“The infections very often are silent,” said Oregon State University researcher Aleksandra Sikora. “Up to 50 percent of infected women don’t have symptoms, but those asymptomatic cases can still lead to some very severe consequences for the patient’s reproductive health, miscarriage or premature delivery.”

The need for better antibiotic therapy, and a vaccine, is pressing. N. gonorrhoeae strains resistant to the last effective treatment options have emerged, and failures in treatment are occurring.

Researchers led by Sikora, an associate professor in the OSU College of Pharmacy, have identified a new therapy target, an enzyme known as AniA. The bacteria need the surface-exposed enzyme to respirate without oxygen, or anaerobically, which is their preferred method of respiration in the biofilms of the genitourinary tract.

A biofilm is a group of one or more types of microorganisms that grow on a wet surface, such as dental plaque on teeth.

Sikora and her team identified a peptide – multiple amino acids linked in a chain – that inhibits the AniA enzyme’s nitrite reductase activity. That in turn damages the bacteria’s ability to grow in the oxygen-poor biofilm environment.

“Bacteria in biofilms display increased resistance to antimicrobials,” Sikora said. “The enzyme is only necessary for cell viability when these bacteria grow under anaerobic conditions, including when they grow in the biofilm. Most antibiotics target essential cell functions; this one doesn’t. It’s only at a certain stage of growth that the bacteria are affected, which means the development of resistance won’t be as fast.”

Through a technique known as biopanning, OSU scientists and collaborators at the University of Kentucky found 29 unique peptides that bound with the targeted enzyme. One of them, C7-3, was identified as most promising for inhibiting the protein’s interaction with nitrite, necessary for anaerobic respiration.

“Imagine this research approach as having a pond with a lot of fish, and you’re using the protein as the bait,” Sikora said. “The peptides bind with the protein, and you go through multiple rounds to identify the peptides that have the strongest binding ability. You start with a billion peptides and end up with one that strongly inhibits the enzyme and ultimately kills the bacteria.”

Findings were recently published in Antimicrobial Agents and Chemotherapy, and Sikora has applied for a provisional patent. The National Institutes of Health and the Medical Research Foundation of Oregon partially supported this research.

The research team included five undergraduate students, four of whom were from Oregon State University.

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Neisseria gonorrhoeae cells

Neisseria gonorrhoeae cells

New approach improves ability to predict metals’ reactions with water

CORVALLIS, Ore. – The wide reach of corrosion, a multitrillion-dollar global problem, may someday be narrowed considerably thanks to a new, better approach to predict how metals react with water.

Researchers at Oregon State University and the University of California, Berkeley, have developed a new computational method that combines two techniques to make predictions faster, less costly and more effective.

The findings, published in Nature Communications, could have a wide range of applications, including in the design of bridges and aircraft engines, both of which are susceptible to corrosion.

Every metal except precious metals like gold and silver reacts with water, said Doug Keszler, distinguished professor of chemistry in Oregon State’s College of Science.

“We’d like to predict the specific reactions of metals and combinations of metals with water and what the products of those reactions are, by computational methods first as opposed to determining them experimentally,” said Keszler, who also serves as director of the Center for Sustainable Materials Chemistry at OSU.

Traditionally, Keszler noted, when looking at metals dissolved in water, the chemical assumption has been that a metal dissolves to form a simple salt. That’s not always what happens, however.

“In many cases, it initially dissolves to form a complex cluster that contains many metal atoms,” he said. “We can now predict the types of clusters that exist in solution, therefore furthering the understanding of metal dissolution from a computational point of view.”

Studying aqueous metal oxide and hydroxide clusters from Group 13 elements – aluminum, gallium, indium and thallium – scientists coupled quantum mechanical calculations with a “group additivity” approach to create Pourbaix diagrams, the gold standard for describing dissolved metal species in water. 

“Applying this new approach, we arrive at a quantitative evaluation of cluster stability as a function of pH and concentration,” said study co-author Paul Ha-Yeon Cheong, associate professor of chemistry at OSU.

Understanding clusters is critical because of the role they play in chemical processes ranging from biomineralization to solution-deposition of thin films for electronics applications. And characterizing corrosion stems from being able to depict metals’ stable phases in water.

“If you’re designing a new steel for a bridge, for example, you’d like to include the potential for corrosion in a computational design process,” Keszler said. “Or if you have a new metal for an aircraft engine, you’d like to be able to determine if it’s going to corrode.”

These examples are not merely hypothetical. Just last summer, a Japanese airline had to refurbish all 100 Rolls-Royce engines on its fleet of Boeing 787 Dreamliners after a series of engine failures caused by the corrosion and cracking of turbine blades. The engines sell for $20 million each.

“Most Pourbaix diagrams do not include these metal clusters and hence our understanding of metal dissolution and reaction with water has been lacking,” said study co-author Kristin A. Persson, professor of materials science at UC Berkeley. “We have now uncovered a fast and accurate formalism for simulating these clusters in the computer, which will transform our abilities to predict how metals react in water.”

The National Science Foundation partially supported this research.

Lindsay Wills, I-Ya Chang and Thomas Mustard of the OSU Department of Chemistry were co-authors of the research, as was Xiaohui Qu of the University of California, Berkeley. 

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Coos Bay bridge

Coastal bridge

Alloying materials of different structures offers new tool for controlling properties

CORVALLIS, Ore. – New research into the largely unstudied area of heterostructural alloys could lead to greater materials control and in turn better semiconductors, advances in nanotechnology for pharmaceuticals and improved metallic glasses for industrial applications.

Heterostructural alloys are blends of compounds made from materials that don’t share the same atom arrangement. Conventional alloys are isostructural, meaning the compounds they consist of, known as the end members, have the same crystal structure.

“Alloys are all around us,” said study co-author Janet Tate, a physicist at Oregon State University. “An example of an istostructural alloy is an LED; you have a semiconductor like aluminum gallium arsenide, dope it with a particular material and make it emit light, and change the color of the light by changing the relative concentration of aluminum and gallium.”

Structure and composition are the two means of controlling the behavior of materials, Tate said. Combining materials gives the alloy properties between those that the end members have individually.

“If two materials have different structures, as you mix them together it’s not so clear which structure will win,” said Tate, the Dr. Russ and Dolores Gorman Faculty Scholar in the College of Science. “The two together want to take different structures, and so this is an extra way of tuning an alloy’s properties, a structural way. The transition between different crystal structures provides an additional degree of control.”

Tate and collaborators from around the world, including the National Renewable Energy Laboratory, published their findings in Science Advances.

“This is a very interesting piece of materials science that represents a somewhat uncharted area and it may be the beginning something quite important,” Tate said. “The heterostructural alloy concept had been known before, but it’s different enough that it hadn’t really been explored in a detailed phase diagram – the mapping of exactly how, at what temperature and what concentration, it goes from one structure to another.

“This paper is primarily the NERL’s theoretical work being supported by other collaborators’ experimental work,” Tate said. “Our involvement at OSU was in making one of the kinds of heterostructural alloys used in the research, the combination of tin sulfide and calcium sulfide.”

Tate and graduate student Bethany Matthews have been focusing on the semiconductor application.

“Tin sulfide is a solar cell absorber, and the addition of calcium sulfide changes the structure and therefore the electrical properties necessary for an absorber,” Tate said “Combining tin sulfide with calcium sulfide makes it more isotropic – properties being the same regardless of orientation – and that’s usually a useful thing in devices.”

In this study, thin-film synthesis confirmed the metastable phases of the alloys that had been predicted theoretically.

“Many alloys are metastable, not stable – if you gave them enough time and temperature, they’d eventually separate,” Tate said. “The way we make them, with pulsed laser deposition, we allow the unstable structure to form, then suppress the decomposition pathways that would allow them to separate; we don’t give them enough time to equilibrate.”

Metastable materials – those that are thermodynamically stable provided they are not subjected to large disturbances – are in general understudied, Tate said.

“When theorists predict properties, they tend to work with materials that are stable,” she said. “In general the stable compounds are easier to attack. The idea here with heterostructural alloys is that they give us a new handle, a new knob to turn to change and control materials’ properties.”

In addition to scientists at the National Renewable Energy Laboratory, the collaboration included researchers at the University of Colorado, the Colorado School of Mines, the SLAC National Accelerator Laboratory, and Harvard University.

The U.S. Department of Energy supported this research.

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Steve Lundeberg, 541-737-4039

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Analyzing magma temperatures may help get closer to forecasting volcanic eruptions

CORVALLIS, Ore. – Although volcanic eruptions are often quite hazardous, scientists have been unable to pinpoint the processes leading up to major eruptions – and one important limitation has been a lack of knowledge about the temperature history of the magma.

A new study analyzed crystals of the mineral zircon – zirconium silicate – in magma from an eruption in the Taupo Volcanic Zone in New Zealand about 700 years ago to determine the magma’s history. The analysis shows the magma went through a comparatively “cool” period for thousands of years before heating up. Once magma temperatures reached 750 degrees Celsius, it was a short amount of time – decades or less – before an eruption occurred.

This pattern of long-term crystal storage in near-solid magma, punctuated by rapid heating, is applicable to many other volcanoes around the world, the researchers say, and may begin to help scientists recognize when a volcano is heading toward an eruptive phase.

Results of the research, which was supported by the National Science Foundation, are being reported this week in Science.

“Mobility in magma is a function of temperature and most of the time when it’s sitting there in the Earth’s crust under the volcano it’s cool,” said Adam Kent, an Oregon State University geologist and co-author on the study. “Of course, cool is a relative description since it’s still some 650 degrees (Celsius). I wouldn’t put my finger on it.

“But to erupt onto the Earth’s surface magma needs to heat up so it can be runny enough to be squeezed along cracks in the Earth and pushed up to the surface. At lower temperatures, the magma is too crystal-rich and viscous to move. It’s like trying to spread cold peanut butter onto a piece of bread. It takes higher temperatures to get things moving – and then our data show it’s only a period of years or decades before it erupts.”

Kent said the Taupo magma system has similarities to many volcanoes around the world, including the Cascade Range in the Pacific Northwest of the United States. A past study by Kent and his colleagues using a different approach found that Mount Hood in Oregon also spent most of its history in a cold, rigid state before moving rapidly into an eruptive phase.

This new study adds more certainty to the method and provides a new tool to apply this work to other volcanoes, the researchers say.

The key to honing in on these long-term geologic processes is understanding the volcanoes’ thermal or temperature history, according to the researchers. Past studies began making inroads into understanding the history of magma temperatures, but they relied on trying to reconcile data from a sample containing many thousands of individual crystals.

Using zircon crystals, which can be dated through analyzing the decay of uranium and thorium, adds more resolution, or precision, to the process. The crystals are like a “black box” flight recorder for studying volcanic eruptions, according to Kari Cooper of the University of California, Davis, corresponding author on the study.

“Instead of trying to piece together what happened from the wreckage,” Cooper said, “the crystals can tell us what was going on while they were below the surface, including the runup to an eruption.”

Zircon crystals occur in magma from many volcanoes and the new technique will have wide applications to volcanoes along the ring of fire – the belt of volcanoes that surround the Pacific Ocean – and elsewhere.

“It removes some uncertainty and gives us a great new tool to go back and look at other volcanoes,” Kent said.

The finding also suggests that if many volcanoes store their magma in this relatively cold state, recognizing volcanoes where warm and mobile magma is present may help researchers find volcanoes in the early throes of producing future eruptions. The technology to monitor volcanoes using seismic waves and other remote techniques is improving all the time, the researchers said.

The Science study was led by Allison Rubin and Cooper of the University of California at Davis. Other researchers included Christy Till and Maitrayee Bose of Arizona State University; Fidel Costa, Nanyang Technological University of Singapore; Darren Gravley and Jim Cole of the University of Canterbury in New Zealand; and Chad Deering, Michigan Technological University.

Kent is on the faculty of the College of Earth, Ocean, and Atmospheric Sciences at Oregon State.

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