Fossil rodent teeth add North American twist to Caribbean mammals' origin story

FLORIDA MUSEUM OF NATURAL HISTORY

Research News

IMAGE: TWO TEETH DISCOVERED IN PUERTO RICO PROVIDE THE FIRST EVIDENCE OF A CARIBBEAN RODENT WITH NORTH AMERICAN ROOTS. RESEARCHERS NAMED THE NEW GENUS AND SPECIES CARIBEOMYS MERZERAUDI. THIS ARTIST'S RECONSTRUCTION... view more 

CREDIT: JORGE VELEZ-JUARBE

GAINESVILLE, Fla. --- Two fossil teeth from a distant relative of North American gophers have scientists rethinking how some mammals reached the Caribbean Islands.

The teeth, excavated in northwest Puerto Rico, belong to a previously unknown rodent genus and species, now named Caribeomys merzeraudi. About the size of a mouse, C. merzeraudi is the Caribbean's smallest known rodent and one of the region's oldest, dating back about 29 million years.

It also represents the first discovery of a Caribbean rodent from a North American lineage, a finding that complicates an idea that has persisted since Darwin - that land-dwelling mammals colonized the islands from South America. The presence of C. merzeraudi in Puerto Rico suggests a second possibility: Some species may have rafted from North America.

The tiny rodent joins two other types of animals, an extinct rhinoceros-like species and bizarre, venomous shrews known as Solenodons, as the only known examples of Caribbean land-dwelling mammals with North American roots.

"This discovery demonstrates that overwater dispersal from North America was also a potential pathway to the Caribbean," said study co-author Jorge Velez-Juarbe, associate curator of mammalogy at the Natural History Museum of Los Angeles County. "This challenges what we thought we knew about the origins of Antillean terrestrial mammals."

While Caribbean ecotourism brochures generally don't feature splashy images of rats, the islands were once home to a rich representation of rodents, including spiny rats, chinchillas, rice rats and hutias - all descendants of South and Central American forebears.

Fossil and molecular evidence suggest these rodents arrived in the islands in multiple waves over time, though how they got there - whether by scurrying over an ancient land bridge, island-hopping or rafting - has been hotly contested. The paucity of fossils from the early years of the Caribbean Islands further obscures the picture of the region's past biodiversity.

Caribeomys merzeraudi's teeth were so unusual that researchers initially struggled to discern what kind of animal they had come from, said study co-author Lazaro Vinola Lopez, a doctoral student in vertebrate paleontology at the Florida Museum of Natural History.

"We didn't know what it was for several months," he said. "We wondered whether this could be some other rodent from the Caribbean or even some kind of strange fish. It was so puzzling because they're not similar to anything else we had found in that region."

The team eventually pinpointed several tooth characteristics that are hallmarks of rodents known as geomorphs, a group that includes kangaroo rats, pocket mice and gophers. Caribeomys merzeraudi is the first geomorph found outside North America.

An exceptionally thick layer of tooth enamel, among other features, sets C. merzeraudi apart from its relatives and could indicate these rodents belonged to a distinct West Indian branch that evolved in isolation over several million years, Vinola Lopez said.

Scientists found the teeth while screen-washing sediment collected from a river outcrop in San Sebastian, a site that has yielded fossil sharks and rays, fish, turtles, a gharial, sea cows and the oldest known frog in the Caribbean, a coqui. In 2019, the team excavated fossil evidence of two large chinchillas, which likely grew up to 30 pounds. These South American rodents once shared Puerto Rico with the humble C. merzeraudi, which weighed less than a quarter pound.

Today, hutias, bats and Solenodons are the "last survivors of what was once a much more diverse group of Caribbean mammals" that included sloths and primates, Velez-Juarbe said.

Discovering C. merzeraudi opens up the tantalizing possibility that Caribbean mammals with North American origins may not be as exceptional as previously thought, Vinola Lopez said. But there's only one way to find out: "Go back to the locality and see what else we can find."

CAPTION

The advanced state of wear on this Caribeomys merzeraudi fossil molar, seen from above in this CT image, leads researchers to believe it came from an old adult.

CREDIT

The Palaeontological Association

Laurent Marivaux of the University of Montpellier was the study's lead author. Other co-authors are Pierre-Henri Fabre of the University of Montpellier and the Natural History Museum; Francois Pujos of the Argentine Institute of Nivology, Glaciology and Environmental Sciences (IANIGLA); Hernan Santos-Merca, Eduardo Cruz, Alexandra Grajales Perez and James Padilla of the University of Puerto Rico; Kevin Velez-Rosado of the University of Michigan; and Jean-Jacques Cornee, Melody Philippon, Philippe Munch and Pierre-Olivier Antoine of the University of Montpellier.

CAPTION

Jorge Velez-Juarbe discovered a fossil site in San Sebastian, Puerto Rico, with fellow undergraduate students in 2006. Excavations have produced fossils from sharks and rays, fish, turtles, a gharial, sea cows and the oldest known frog and rodents in the Caribbean. From top, the paleontologists pictured here are Lazaro Vinola Lopez, Jorge Velez-Juarbe, Francois Pujos and Laurent Marivaux.

CREDIT

Pierre-Olivier Antoine

 

Modified yeast inhibits fungal growth in plants

External application could reduce agricultural reliance on fungicides

UNIVERSITY OF CALIFORNIA - RIVERSIDE

Research 

About 70-80% of crop losses due to microbial diseases are caused by fungi. Fungicides are key weapons in agriculture's arsenal, but they pose environmental risks. Over time, fungi also develop a resistance to fungicides, leading growers on an endless quest for new and improved ways to combat fungal diseases.

The latest development takes advantage of a natural plant defense against fungus. In a paper published in Biotechnology and Bioengineering, engineers and plant pathologists at UC Riverside describe a way to engineer a protein that blocks fungi from breaking down cell walls, as well as a way to produce this protein in quantity for external application as a natural fungicide. The work could lead to a new way of controlling plant disease that reduces reliance on conventional fungicides.

To gain entrance into plant tissues, fungi produce enzymes that use catalytic reactions to break down tough cell walls. Among these are polygalacturonases, or PGs, but plants are not helpless against this attack. Plants produce proteins called PG-inhibiting proteins, or PGIPs, that slow catalysis.

A group of UC Riverside researchers located the segment of DNA that tells the plant how to make PGIPs in common green beans. They inserted complete and partial segments into the genomes of baker's yeast to make the yeast produce PGIPs. The team used yeast instead of plants because yeast has no PGIPs of its own to muddy the experiment and grows quicker than plants.

After confirming the yeast was replicating with the new DNA, the researchers introduced it to cultures of Botrytis cinerea, a fungus that causes gray mold rot in peaches and other crops; and Aspergillus niger, which causes black mold on grapes and other fruits and vegetables.

Yeast that had both the complete and partial DNA segments that coded for PGIP production successfully retarded fungal growth. The result indicates the yeast was producing enough PGIPs to make the method a potential candidate for large-scale production.

"These results reaffirm the potential of using PGIPs as exogenous applied agents to inhibit fungal infection," said Yanran Li, a Marlan and Rosemary Bourns College of Engineering assistant professor of chemical and environmental engineering, who worked on the project with plant pathologist Alexander Putman in the Department of Microbiology and Plant Pathology. "PGIPs only inhibit the infection process but are likely not fatal to any fungi. Therefore, the application of this natural plant protein-derived peptide to crops will likely have minimal impact on plant-microbe ecology."

Li also said that PGIPs probably biodegrade into naturally occurring amino acids, meaning fewer potential effects for consumers and the environment when compared with synthetic small molecule fungicides.

"The generation of transgenic plants is time-consuming and the application of such transgenic crops in agricultural industry requires a long approval period. On the other hand, the engineered PGIPs that are derived from natural proteins are applicable as a fast-track product for FDA approval, if they can be utilized exogenously in a manner similar to a fungicide," Li said.

By tweaking the yeast a slightly different way, the researchers were able to make it exude PGIPs for external application. Previous studies have shown freeze drying naturally occurring microbes on apples, then reconstituting them in a solution and spraying them on crops, greatly reduces fungal disease and loss during shipping. The authors suggest that PGIP-expressing yeast could be used the same way. They caution, however, that because plants also form beneficial relationships with some fungi, future research needs to ensure plants only repel harmful fungi.

Li will continue to engineer PGIPs for enhanced efficiency and broader spectrum against various pathogenic fungi. Meanwhile, Li and Putman will keep evaluating the potential of using engineered PGIPs to suppress fungi-induced pre-harvest and post-harvest disease.

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Li and Putman were joined in the research by doctoral student Tiffany Chiu and plant pathologist Anita Behari, both of whom are at UC Riverside, and Justin Chartron, who was a professor at UC Riverside when the research was conducted. The paper, "Exploring the potential of engineering polygalacturonase?inhibiting protein as an ecological, friendly, and nontoxic pest control agent," is available here. The work was supported by LG Chem Ltd. and the Frank G. and Janice B. Delfino Agricultural Technology Research Initiative and partially supported by the National Institutes of Health.

 

A new avenue for fighting drug-resistant bacteria

Targeting an RNA sequence in pathogenic bacteria could make them more sensitive to antibiotics

INSTITUT NATIONAL DE LA RECHERCHE SCIENTIFIQUE - INRS

Research News

 

IMAGE: INRS PROFESSOR CHARLES DOZOIS, SPECIALIST IN MICROBIOLOGY AND IMMUNOLOGY AND THE IDENTIFICATION AND CHARACTERIZATION OF BACTERIAL GENES AFFECTING HUMANS, POULTRY AND PIGS. view more 

CREDIT: CHRISTIAN FLEURY (INRS)

A small regulatory RNA found in many problematic bacteria, including Escherichia coli, appears to be responsible for managing the response of these bacteria to environmental stresses. Professor Charles Dozois from Institut national de la recherche scientifique (INRS) and doctoral student Hicham Bessaiah see a promising avenue for more effective treatment of antibiotic-resistant bacteria. Their results have been published in the journal PLOS Pathogens.

In conducting their work, the researchers and their team observed that the elimination of this regulatory RNA sequence had an effect on urinary tract infections related to E. coli. These infections are among the world's most common, especially in women, but they are sometimes hard to treat due to antibiotic resistance.

E. coli is normally found in the intestinal flora, but when it migrates to the bladder, the conditions there are completely different. The bacteria have to withstand the environmental stressors in order to cause a bladder infection. "Without the regulatory RNA, the bacteria is more sensitive to changes in the environment and loses its infectious capacity," explained the doctoral student.

Inhibiting the RNA sequence

The idea is to block the RNA and make the bacteria less infectious, especially in the case of chronic infection, which can lead to increased resistance to treatment. If the bacteria are less resistant to stress, it will be more vulnerable to the host's immune response. Regulation of the systems that make it virulent will also be disrupted.

"People with recurrent urinary tract infections take antibiotics regularly. This leads to resistance and limits treatment options, which is why it's important to find alternatives," explained Professor Dozois.

The relationship between virulence and stress isn't unique to urinary tract infections. The regulatory RNA sequence studied by the researchers is also found in a number of other major pathogenic bacteria. Given that the RNA seems to impact multiple functions, the research group is working to better understand the mechanisms of regulation before pursuing additional research on antibiotic-resistant strains of bacteria.

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About the study

The article "The RyfA small RNA regulates oxidative and osmotic stress responses and virulence in uropathogenic Escherichia coli" by Hicham Bessaiah, Pravil Pokharel, Hamza Loucif, Merve Kulbay, Charles Sasseville, Hajer Habouria, Sébastien Houle, Jacques Bernier, Éric Massé, Julien Van Grevenynghe, and Charles M. Dozois was published in PLOS Pathogens. The research group received financial support from the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canadian Institutes of Health Research (CIHR), and the Swine and Poultry Infectious Diseases Research Centre (CRIPA) funded by Fonds de recherche du Québec - Nature et technologies (FRQNT).

About INRS

INRS is a university dedicated exclusively to graduate level research and training. Since its creation in 1969, INRS has played an active role in Québec's economic, social, and cultural development and is ranked first for research intensity in Québec and in Canada. INRS is made up of four interdisciplinary research and training centres in Québec City, Montréal, Laval, and Varennes, with expertise in strategic sectors: Eau Terre Environnement, Énergie Matériaux Télécommunications, Urbanisation Culture Société, and Armand-Frappier Santé Biotechnologie. The INRS community includes more than 1,500 students, postdoctoral fellows, faculty members, and staff.

 

Emotion, cooperation and locomotion crucial from an early age

Researchers at the UNIGE have found that emotion knowledge, cooperative social behavior and locomotor activity are three key skills for promoting numerical learning in children aged 3 to 6

UNIVERSITÉ DE GENÈVE

Research News

IMAGE: CONTENT OF ITEM 1 OF THE SECOND PART OF THE EMOTION AWARENESS TASK. THE INSTRUCTIONS ARE AS FOLLOWS: LEFT: THIS BOY HAS JUST RECEIVED A PRESENT FOR HIS BIRTHDAY. RIGHT:... view more 

CREDIT: © UNIGE

What are the fundamental skills that young children need to develop at the start of school for future academic success? While a large body of research shows strong links between cognitive skills (attention, memory, etc.) and academic skills on the one hand, and emotional skills on the other, in students from primary school to university, few studies have explored these links in children aged 3 to 6 in a school context. Researchers from the University of Geneva (UNIGE) and Valais University of Teacher Education, Switzerland (HEP-VS), in collaboration with teachers from Savoie in France and their pedagogical advisor, examined the links between emotion knowledge, cooperation, locomotor activity and numerical skills in 706 pupils aged 3 to 6. The results, to be read in the journal Scientific Reports, show for the first time that emotion knowledge, cooperative social behaviour and locomotor activity are interrelated and associated with numerical skills. These results are in line with the political and scientific consensus on the importance of social-emotional skills in early schooling and suggest that locomotor activity should be added to these fundamental skills.

A growing number of studies are examining the fundamental abilities that prepare children for school and that are particularly crucial for their future academic success. "Among these abilities, 'emotion knowledge' contributes significantly and is a long-term predictor of social behaviour and academic success", says Edouard Gentaz, professor in the Department of Psychology at the Faculty of Psychology and Educational Sciences (FPSE) of the UNIGE and the last author of this study. On the other hand, few studies have examined the links between socio-emotional and academic skills in preschool children. "To fill this gap, we joined forces with the HEP-VS and a team of teachers from Savoie in France and their pedagogical advisor to examine how emotion knowledge, social behaviour and locomotor activity are associated and linked to the numerical skills in 706 pupils aged between 3 and 6 years old", continues the Geneva-based researcher. Unlike most research that generally examines school results through reading tests, this study focuses on numerical learning, the performance of which is less correlated with parents' socio-economic level than language skills.

Original tests adapted to the preschool age and educational context

To examine the links between the four variables studied, age-appropriate tests were developed in close collaboration with 33 volunteer teachers, who participated in an interactive workshop in which they were trained to set up, perform and evaluate the different tests in a standardised manner. Thus, emotion knowledge was assessed through two emotion comprehension tasks. The first measured the recognition of the primary emotions of anger, fear, joy and sadness as well as a neutral facial expression and the second measured the understanding of the external causes underlying these emotions in others. This second task was subdivided into two different subtasks: the teacher successively presented the student with five drawing scenarios illustrated by a picture of a character with a blank face facing a particular situation (e.g., 'This boy has just received a present for his birthday') and then asked the student to indicate, among five illustrations of facial expressions, the one that corresponded to what the character felt in each situation, first by pointing to it (non-verbal responses) and then by naming it. The assessment of mathematical skills included three numerical tests. For example, the first test sought to assess whether students understood that the cardinal of a collection does not change when the spatial arrangement or nature of its elements is modified: the teacher placed a photograph in front of the student showing four collections of objects (two of which were composed of the same number of elements) and asked the student to indicate which collection contained the largest number of objects, which contained the fewest, and which two collections contained the same number.

Working closely with the teachers and their advisor, the psychologists developed observation grids to assess the locomotor activity and social behaviour of the pupils. For locomotor activity, the grid created made it possible to rate the children's performance on an agility course consisting of various installations on the ground and in the air. As for social behaviour, the grid developed made it possible to evaluate the children's reactions and attitudes during the practice of two different team games (one with a ball and the other without) observed by the teachers.

Key skills to promote numerical learning

The results of this study reveal that emotion knowledge, locomotor activity and social behaviour are interdependent and associated with pupils' numerical skills from the age of 3 to 6 years. "Indeed, specific statistical analyses (regression and mediation) show that high scores on tests assessing emotion knowledge, locomotor activity and social behaviour predict better mathematical performance in these students", notes Thalia Cavadini, researcher in the Department of Psychology at FAPSE and first author of the study. "Thus, our results are in line with the scientific consensus on the importance of social-emotional skills at the beginning of schooling and suggest that locomotor activity should be added to these fundamental skills", she concludes. Furthermore, this study is the first to show that emotional, social and locomotor skills promote school learning in toddlers.

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Study: Incarcerated people placed in solitary confinement differ significantly from others in prison population

CRIME AND JUSTICE RESEARCH ALLIANCE

Research News

Concern has grown about prison systems' use of extended solitary confinement as a way to manage violent and disruptive incarcerated people. A new study identified groups that are more likely to be placed in extended solitary management (ESM). The study found that individuals sent to ESM differed considerably from the rest of the prison population in terms of mental health, education, language, race/ethnicity, and age.

The study, by researchers at Florida State University and the University of Cincinnati, appears in Justice Quarterly, a publication of the Academy of Criminal Justice Sciences.

"Many states and the federal prison system rely on long-term solitary confinement as a management tool, so it is important to shed light on the placements and disparities in this form of incarceration," according to Daniel P. Mears, professor of criminology at Florida State University, who led the study.

Prisoners have been placed in solitary confinement for more than 200 years. But in recent decades--especially with the rise of "supermax" prisons in the 1980s--correctional facilities have increased their reliance on the practice, with less focus on rehabilitation and more on control and punishment. Recent decades have also seen the rise of "restrictive housing" of incarcerated people, which includes confinement used for punishment or protection, and can limit privileges significantly.

ESM stands at the center of debates about solitary confinement: Critics argue that it is inhumane, unconstitutional, and harmful, especially to individuals with mental health disorders, while proponents say it is necessary for prison safety and order. Research on ESM is limited.

In this study, researchers used administrative records from the Florida Department of Corrections for approximately 192,000 individuals who entered or were released between 2007 and 2015. In this prison system, one of the largest in the United States, ESM typically entails a minimum stay of six months and up to 23 hours per day in isolation in a separate facility.

The study sought to identify disparities along a broad range of characteristics, including those related to demographics (e.g., age at admission, gender, race/ethnicity), mental health, substance abuse, education, language (i.e., English language proficiency), and prior criminal records (e.g., prior admissions, offense, time served). It also looked at disparities in placement, including multiple, early, and longer-duration placements.

Several patterns emerged from the study:

• The profile of the population sent to ESM differed substantially from that of the rest of the admission-and-release population: Those sent to ESM were much more likely to be adolescents or young adults, males were more likely than females to be sent to ESM, and Blacks comprised 63 percent of the ESM population but just 43 percent of the overall prison population.
• Mental health disparities were also pronounced: Individuals who spent time in a mental health unit or required outpatient care with medication were more likely to be placed in ESM early in their incarceration and have longer stays.
• Other disparities appeared: Education among the ESM population was 1.6 grade levels lower than that for the prison population as a whole. Non-English speakers had a lower likelihood of an ESM stay than English speakers after controlling for age, sex, and other factors. Hispanics were more likely than others to be placed in ESM within six months of admission to prison. And stays of a year or longer in ESM were less likely among Hispanics and more likely among males and individuals with no prior prison admissions.
• Early, repeated, and longer-duration placement in ESM was not the norm: 11 percent of all ESM incarceration stays entailed two or more ESM placements, 21 percent entailed an ESM placement within six months of admission, and 27 percent spent a year or more in ESM. There were relatively few differences in the profiles of these three groups.

"A focus on disparities in ESM placements is important for advancing research and policy," notes Jennifer M. Brown, a post-doctoral research fellow at Florida State University, who coauthored the study. "We need to understand more about the factors that contribute to placements. For example, some groups may engage in more violent or disruptive behavior, which could create the disparities. It also is possible that prison system practices may disadvantage certain groups or contribute to conditions that increase problematic behavior among those groups. In addition, it is possible that some groups may benefit more or be harmed more by ESM."

The authors point to a few limitations of their study, including that it focused on one state and one time period, so studies of other states and longer time periods might differ. In addition, the study did not include individuals who served more than eight years, which likely excluded inmates serving sentences for extremely violent crimes. Finally, the study relied on administrative records, which are not always accurate in capturing information such as individuals' mental health or organizational factors that might contribute to placements.

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The research was supported by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice. Points of view in the study were those of the authors and did not necessarily represent the official position or policies of the U.S. Department of Justice or the Florida Department of Corrections.

 

Kelp for corn? Illinois scientists demystify natural products for crops

UNIVERSITY OF ILLINOIS COLLEGE OF AGRICULTURAL, CONSUMER AND ENVIRONMENTAL SCIENCES

Research News

IMAGE: UNIVERSITY OF ILLINOIS SCIENTISTS, INCLUDING CONNOR SIBLE (PICTURED), ARE MAKING IT EASIER FOR FARMERS TO CHOOSE BIOSTIMULANT PRODUCTS TO BOOST CORN PRODUCTION WITH A NEW ARTICLE BREAKING DOWN COMPOSITION, MECHANISMS,... view more 

CREDIT: UNIVERSITY OF ILLINOIS

URBANA, Ill. - Corn growers can choose from a wide array of products to make the most of their crop, but the latest could bring seaweed extract to a field near you. The marine product is just one class in a growing market of crop biostimulants marketed for corn.

Biostimulants benefit crops and soil, but the dizzying array of products has farmers confused, according to Fred Below, corn and soybean researcher at the University of Illinois.

"Farmers hear the term 'plant biostimulant' and think they all do the same thing, and can be used in the same way at the same time. But that's not the case. There's huge confusion over what these products do, and when and how they should be used," says Below, professor in the Department of Crop Sciences at Illinois.

To quell the confusion, Below, along with doctoral student Connor Sible and research specialist Juliann Seebauer, categorized available biostimulant products into eight classes based on their modes of action. Their review, which includes summaries of product composition, mechanisms, efficacy, and application considerations, is published in the journal Agronomy.

Generally, plant biostimulants enhance natural processes in plants or soil that, in turn, boost crop quality and yield through enhanced nutrient uptake, nutrient efficiency, or stress tolerance.

According to the researchers' classification system, half of the products are live microorganisms, including nitrogen-fixing bacteria, mycorrhizal fungi, phosphorus-solubilizing microbes, or other beneficial microbes. The other half are chemistries or chemical byproducts from "formerly living" organisms, as Sible puts it. These include seaweed extracts, humic and fulvic acids, concentrated enzymes, and biochar.

It's not always completely clear how or why biostimulants work the way they do, but Sible and Below say there's a time and a place for each. It's up to the grower to consider which biostimulant fits their goal.

"When we talk to growers, that's the first thing we say. What is the problem you're having, and what is it you're trying to accomplish? Then we can suggest which product from this or that biostimulant category might be your best bet," Below says.

Sible adds, "Sometimes farmers will try these products because the sales pitch sounds good, but they won't get the response they want in the field. So they'll walk away from all biostimulants. Those kinds of poor outcomes could be prevented with more information. That's why we felt this was important. We're actively researching these products to help growers understand what they are and how they work, so they can select the right one for their production system."

Many of the products target nutrient management, with an eye toward reducing or replacing application of synthetic fertilizers. For example, soybean growers are familiar with nitrogen-fixing microorganisms, but Sible says new technologies, including gene editing, are enabling these microbes to thrive in the corn root zone as well.

"We see in our research that these products can help you be more efficient with your fertilizer," he says. "It's all about better management and stewardship of nutrients. If we can add something to our fertilizer plan to make that happen, it's a win-win."

Plant biostimulants aren't new. Specialty growers have applied nitrogen-fixing bacteria, mycorrhizal fungus, seaweed extracts, and similar products for years. But as start-up companies have scaled up production or partnered with big seed and fertilizer companies, they've started eyeing the row crop market.

"All the big companies have partnerships in the biological world now, because it's viewed as part of sustainability or regenerative ag. Some of these products purport to have soil health benefits, and that's all the rage," Below says.

Sible adds that some of the big seed companies are already coating seeds with live inoculants to give seedlings a solid start. "A lot of growers are actually using biostimulants without necessarily knowing it."

Seed coatings are only one method of application. Below says including biostimulant application with standard management practices, such as in-furrow application at seeding or during an herbicide or fungicide pass, provides a free ride for the products.

"When biostimulants can go in with practices that are already being done, that makes their application cost-effective," he says.

Sible notes the average cost of biostimulants is $8 to $12 per acre, but some of the microbial products push $20 to $25. Despite the expense, Below says a lot of farmers are willing to invest this year.

"Commodity prices are really quite high right now, so farmers might be thinking, 'Why don't I try something I normally wouldn't try?' We just want to have them try something that has a greater likelihood to be worthwhile," he says.

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The article, "Plant biostimulants: A categorical review, their implications for row crop production, and relation to soil health indicators," is published in Agronomy [DOI: 10.3390/agronomy11071297]. Partial funding was provided by the USDA's National Institute of Food and Agriculture.

The Department of Crop Sciences is in the College of Agricultural, Consumer and Environmental Sciences at the University of Illinois.

Disclaimer: AAAS and EurekAlert! are not responsible for the a

Climate regulation changed with the proliferation of marine animals and terrestrial plants

Geoscientific study traces carbon-silicon cycle over three billion years on the basis of lithium isotope levels

JOHANNES GUTENBERG UNIVERSITAET MAINZ

Research News

IMAGE: BORIANA KALDERON-ASAEL COLLECTING 450-MILLION-YEAR-OLD ROCK SAMPLES IN PENNSYLVANIA, USA view more 

CREDIT: PHOTO/©: ASHLEIGH HOOD

Earth's climate was relatively stable for a long period of time. For three billion years, temperatures were mostly warm and carbon dioxide levels high - until a shift occurred about 400 million years ago. A new study suggests that the change at this time was accompanied by a fundamental alteration to the carbon-silicon cycle. "This transformation of what was a consistent status quo in the Precambrian era into the more unstable climate we see today was likely due to the emergence and spread of new life forms," said Professor Philip Pogge von Strandmann, a geoscientist at Johannes Gutenberg University Mainz (JGU). Together with researchers from Yale University, notably Boriana Kalderon-Asael and Professor Noah Planavsky, he has traced the long-term evolution of the carbon-silicon cycle with the help of lithium isotopes in marine sediments. This cycle is regarded as a key mechanism controlling the Earth's climate, as it regulates carbon dioxide levels and, with it, temperature. The researchers' findings have been published recently in Nature.

The carbon-silicon cycle is the key regulator of climate

The carbon-silicon cycle has kept Earth's climate stable over long periods of time, despite extensive variations in solar luminosity, in atmospheric oxygen concentrations, and the makeup of the Earth's crust. Such a stable climate created the conditions for long-term colonization of the Earth by life and allowed initially simple and later complex life forms to develop over billions of years. The carbon-silicon cycle contributes to this by regulating the level of carbon dioxide in the atmosphere. Silicate rock is transformed into carbonate rock as a result of weathering and sedimentation, and carbonate rock is transformed back into silicate rock by, among other things, volcanism. When silicate rock is converted to carbonate rock, carbon dioxide is removed from the atmosphere, while the reverse process releases carbon dioxide once again. "We consider this to be the main mechanism by which Earth's climate is stabilized over the long term," explained Pogge von Strandmann.

To trace long-term carbon-silicon cycles back in time and gain a better understanding of the precise relationships governing Earth's climate, the research team studied the ratio of lithium isotopes in marine carbonates. Lithium is present only in silicate rocks and their silicate and carbonate weathering products. The research team analyzed more than 600 samples deposited as sediments in shallow primeval marine waters and obtained from more than 100 different rock strata from around the world, including from Canada, Africa and China. "We used these samples to create a new database covering the past three billion years," Pogge von Strandmann pointed out.

These data show that the ratio of lithium-7 to lithium-6 isotopes in the oceans was low from three billion years ago to 400 million years ago, and then suddenly increased. It was precisely at this time that land plants evolved, while simultaneously marine animals with skeletons composed of silicon, such as sponges and radiolarians, spread throughout the oceans. "Both played a role, but as yet we do not know exactly how the processes are coupled," Professor Philip Pogge von Strandmann added.

The displacement of 'clay factories' to the land influences the carbon-silicon cycle

Research findings suggest that there was a massive change to the extent of the formation of clay, a secondary silicate rock composed of very fine particles, in the Earth's past - possibly due to an increase in clay formation on land and a decrease in the oceans. Clay formation is a crucial component of the carbon-silicon cycle and it influences the ratio of lithium isotopes. On land it is caused by the extensive weathering of silicate rocks, but in the oceans a range of different processes is involved. Increased continental clay formation is thought to have lowered carbon dioxide levels in the atmosphere. In contrast, oceanic clay formation, known as "reverse weathering", releases CO2, so its decline will similarly have lowered atmospheric carbon dioxide levels.

According to the authors of the Nature paper, this suggests that the mode of climate regulation on Earth as well as the primary location where that process occurs has changed dramatically through time: "The shift from a Precambrian Earth state to the modern state can probably be attributed to major biological innovations - the radiation of sponges, radiolarians, diatoms and land plants." The result of this modification of climate regulation has been apparent ever since in the form of the frequent alternation between cold glacial periods on the one hand and warmer periods on the other. However, this climate instability, in turn, helps to accelerate evolution.

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When fawns perceive constant danger from many sources, they almost seem to relax

Researchers use trail cameras to study animals' interaction, behavior in human-dominated landscapes

PENN STATE

Research News

IMAGE: THESE FAWNS ARE SHOWING VIGILANCE. BUT WHEN YOUNG WHITE-TAILED DEER PERCEIVE THAT THERE IS SO MUCH DANGER COMING FROM SO MANY SOURCES, THEIR BEHAVIOR SEEMED LIKE THEY JUST RELAXED, ACCORDING... view more 

CREDIT: ASIA MURPHY/PENN STATE

Burnout. It is a syndrome that is said to afflict humans who feel chronic stress. But after conducting a novel study using trail cameras showing the interactions between white-tailed deer fawns and predators, a Penn State researcher suggests that prey animals feel it, too.

"And you can understand why they do," said Asia Murphy, who recently graduated with a doctorate from Penn State's Intercollege Graduate Degree Program in Ecology. "Less than half of whitetail fawns live to see their first birthday, and many are killed by predators, such as coyotes, black bears and bobcats. Fawns instinctively 'know' they are in constant danger."

Ironically, the presence of humans -- who mean the fawns no harm and likely would protect them if they could -- only ratchets up the stress the young animals experience, Murphy added. Even if it's just people hiking on a trail in a state park, it is a disturbance to be avoided by fawns, leaving less landscape and less time for them to feed and evade predators.

"The presence of people creates an environment where the danger seems so high that the animals basically stop having vigilance behaviors," she said. "That was the surprising thing about my research -- when fawns perceive that there is so much danger coming from so many sources, their behavior seemed like they just relaxed, like there's no point in being ready to hide or flee. I saw that in older deer, too."

In areas where there are many predators and people present, fawns seem to relax instead of acting hypervigilant, she noted.

"Like so much constant stress leaves them burned out," she said.

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This "camera trap" photo says it all: Less than half of whitetail fawns live to see their first birthday, and many are killed by predators, such as black bears, bobcats, and coyotes like the one shown here carrying the head of a fawn.

CREDIT

Asia Murphy/Penn State

The goal of the study was to examine how human-dominated landscapes influence the timing, frequency and physical spacing and locations of interactions between humans, black bears, coyotes, bobcats and fawns, as well as to contrast deer vigilance behavior at each location. The researchers compared "camera trap" data from six surveys in and around three central Pennsylvania public forest sites with different surroundings -- forest, agriculture and development.

The Bald Eagle and Rothrock State Forest sites were surrounded by agriculture and low-density housing, whereas the Susquehannock State Forest site was surrounded by largely unbroken forest. Analyzing more than 10,000 photos, researchers observed markedly different behavior of fawns, adult deer and predators at the three locations, dictated, they suggest, by the presence of humans and their changes to the landscape.

Camera trap surveys began in mid- to late-May, which coincided with the start of the period when fawns are born and are most vulnerable to predation, and ended in mid-September, before the hunting season. Researchers randomly established 18 camera locations at each of the three study sites, spaced a minimum of a half mile apart within an area of about 100 square miles.

At least one camera was placed at each location and typically remained there for an average of 47 days before being moved to a new location. Cameras were set to take three pictures when triggered by an animal with a one-minute rest period. Each location was baited with a combination of bobcat urine, a skunk-based scent attractant and a fatty acid tablet.

In findings recently published in the Journal of Animal Ecology, the researchers reported that bears, bobcats, coyotes, fawns and adult deer all had more frequent timing overlaps in the agriculture and development sites compared to the mostly unbroken forest site. In addition, factors that influenced deer vigilance, such as distance to forest edge and predator abundance in the agriculture and development sites, were not factors in the mostly unbroken forest site.

"By taking into account the different antipredator behaviors that can be detected and the different scales at which these behaviors might occur, we were able to gain a more comprehensive picture of how humans reduce available niche space for wildlife," Murphy said. "It was clear that disturbed landscapes -- agriculture and development -- create more time and space overlap between predators and fawns."

This research is important because it is among the first to document that human land disturbance influences the dynamics of predator-prey interactions, according to Murphy's adviser, Duane Diefenbach, adjunct professor of wildlife ecology in the College of Agricultural Sciences. Wildlife biologists suspected human interference enhances opportunities for predators, but they had not seen proof.

"This study shows that antipredator behavior by fawns varies across space, time and predator species," said Diefenbach, who is leader of the U.S. Geological Survey's Pennsylvania Cooperative Fish and Wildlife Research Unit at Penn State. "When multiple predator species co-occur but vary in their use of space, time of activity and hunting mode, it creates a complex landscape for prey trying to avoid predation. Human presence has the potential to shift interactions among predators and prey and where and when encounters occur."

CAPTION

When multiple predator species such as this bobcat co-occur but vary in their use of space, time of activity and hunting mode, researchers say, it creates a complex landscape for prey like fawns trying to avoid predation.

CREDIT

Asia Murphy/Penn State

Also involved in the research was David Miller, associate professor of wildlife population ecology, Penn State, and Pennsylvania Game Commission biologists Mark Ternent and Matt Lovallo.

The Pennsylvania Game Commission funded and supported this research.

 

University of Minnesota develops new tool to help farmers make crop input decisions

Understanding the cost and social benefits of using less nitrogen across the US corn belt

UNIVERSITY OF MINNESOTA

Research News

Reducing greenhouse gas emissions (GHGs) and nitrogen water pollution from agriculture are top environmental priorities in the United States. Key to achieving climate goals is helping producers navigate carbon markets, while also helping the environment and improving farm income.

A new tool developed by a University of Minnesota research team allows farmers to create a budget balance sheet of any nitrogen reduction plans and see the economic and environmental cost, return and margins, all customized to fields under their management.

"With these numbers in mind, farmers can make more informed decisions on nitrogen mitigation that not only saves them money, but also significantly reduces pollutants to the environment," said Zhenong Jin, who led the research and is an assistant professor in the Department of Bioproducts and Biosystems Engineering (BBE) in the College of Food, Agricultural and Natural Resource Sciences (CFANS).

Previous tools did not allow for customized predictions for every field in the U.S. corn belt, as the computational and storage costs of running these crop models at large scale would be very expensive.

As outlined in an article published in IOPscience, the research team built a series of machine-learning-based metamodels that can almost perfectly mimic a well-tested crop model at much faster speeds. Using the metamodels, they generated millions of scenario simulations and investigated two fundamental sustainability questions -- where are the mitigation hotspots, and how much mitigation can be expected under different management scenarios.

"We synthesized four simulated indicators of agroecosystem sustainability -- yield, N2O emissions, nitrogen leaching, and changes in soil organic carbon -- into economic net societal benefits as the basis for identifying hotspots and infeasible land for mitigation," said Taegon Kim, CFANS research associate in the BBE department. The societal benefits include cost savings from GHG mitigation, as well as improved water and air quality.

"By providing key sustainability indicators related to upstream crop production, our metamodels can be a useful tool for food companies to quantify the emissions in their supply chain and distinguish mitigation options for setting sustainability goals," said Timothy Smith, professor of Sustainable Systems Management and International Business Management in CFANS's BBE department.

The study, conducted in the U.S. Midwest corn belt, found that:

• Reducing nitrogen fertilizer by 10% leads to 9.8% less N2O emissions and 9.6% less nitrogen leaching, at the cost of 4.9% more soil organic carbon depletion, but only a 0.6% yield reduction over the study region.
• The estimated net total annual social benefits are worth $395 million (uncertainty ranges from $114 million to nearly $1.3 billion), including a savings of $334 million by avoiding GHG emissions and water pollution, $100 million using less fertilizer, and a negative $40 million due to yield losses.
• More than 50% of the net social benefits come from 20% of the study areas, thus can be viewed as hot spots where actions should be prioritized.

"Our analysis revealed hot spots where excessive nitrogen fertilizer can be cut without yield penalty," said Jin. "We noticed in some places that reducing nitrogen-related pollution comes at a cost of depleting organic carbon in soil, suggesting that other regenerative practices, such as cover cropping, need to be bundled with nitrogen management."

In the future, the team will expand the framework presented in this study and develop more advanced and accurate carbon qualification models through a combination of process-based models, artificial intelligence and remote sensing.

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This research was funded by the University of Minnesota AGREETT program, the National Science Foundation and the U.S. Department of Energy Advanced Research Projects Agency-Energy (ARPA-E).

International team of scientists turns methane into methanol at room temperature

STANFORD UNIVERSITY

Research News

IMAGE: BENJAMIN SNYDER (RIGHT) AND HIS FORMER PHD ADVISER, EDWARD SOLOMON, A PROFESSOR OF CHEMISTRY AT STANFORD AND OF PHOTON SCIENCE AT SLAC. view more 

CREDIT: LINDA A. CICERO

A team of researchers from Stanford University and the University of Leuven in Belgium has further elucidated an intriguing process that could be an important step toward a methanol fuel economy with abundant methane as the feedstock, an advance that could fundamentally change how the world uses natural gas.

Methanol - the simplest alcohol - is used to make various products, like paints and plastics, and as an additive to gasoline. Rich in hydrogen, methanol can drive new-age fuel cells that could yield significant environmental benefits.

If natural gas, of which methane is the primary component, could be converted economically into methanol, the resulting liquid fuel would be much more easily stored and transported than natural gas and pure hydrogen. That also would greatly reduce the emissions of methane from natural gas processing plants and pipelines. Today, escaped methane, a greenhouse gas many times more potent than carbon dioxide, nearly negates the environmental advantages of natural gas over oil and coal. The team's new study in the current edition of Science is their latest to advance a low-energy way to produce methanol from methane.

"This process uses common crystals known as iron zeolites that are known to convert natural gas to methanol at room temperature," explains Benjamin Snyder, who earned his doctorate at Stanford studying catalysts to address key facets of this challenge. "But, this is extremely challenging chemistry to achieve on a practical level, as methane is stubbornly chemically inert."

When methane is infused into porous iron zeolites, methanol is rapidly produced at room temperature with no additional heat or energy required. By comparison, the conventional industrial process for making methanol from methane requires temperatures of 1000°C (1832°F) and extreme high pressure.

"That's an economically tantalizing process, but it's not that easy. Significant barriers prevent scaling up this process to industrial levels," said Edward Solomon, Stanford professor of chemistry and of photon science at SLAC National Accelerator Laboratory. Solomon is the senior author of the new study.

Keeping the zeolites on

Unfortunately, most iron zeolites deactivate quickly. Unable to process more methane, the process peters out. Scientists have been keen to study ways to improve iron zeolite performance. The new study, co-authored by Hannah Rhoda, a Stanford doctoral candidate in inorganic chemistry, uses advanced spectroscopy to explore the physical structure of the most promising zeolites for methane-to-methanol production.

"A key question here is how to get the methanol out without destroying the catalyst," Rhoda said.

Choosing two attractive iron zeolites, the team studied the physical structure of the lattices around the iron. They discovered that the reactivity varies dramatically according to the size of the pores in the surrounding crystal structure. The team refers to it as the "cage effect," as encapsulating lattice resembles a cage.

If the pores in the cages are too big, the active site deactivates after just one reaction cycle and never reactivates again. When the pore apertures are smaller, however, they coordinate a precise molecular dance between the reactants and the iron active sites - one that directly produces methanol and regenerates the active site. Leveraging this so-called 'cage effect,' the team was able to reactivate 40 percent of the deactivated sites repeatedly - a significant conceptual advance toward an industrial-scale catalytic process.

CAPTION

An illustration of the cage structures of two iron-based zeolites used in the study. The red and gold spheres (representing oxygen and iron, respectively) make up the active site. The cage structure, in gray, is formed of silicon, aluminum and oxygen. The blue sphere quantifies the size of the largest molecule that can diffuse freely in and out of the active site cage (the diameter of methane is ~4.2 Å).

CREDIT

Benjamin Snyder

"Catalytic cycling - the continual reactivation of regenerated sites - could someday lead to continual, economical methanol production from natural gas," said Snyder, now a postdoctoral fellow at UC-Berkeley in the Department of Chemistry under Jeffrey R. Long.

This fundamental step forward in basic science will help elucidate for chemists and chemical engineers the process iron zeolites use to produce methanol at room temperature, but much work remains before such a process might be industrialized.

Next up on Snyder's list: tackling achieving the process not only at room temperature but using ambient air rather than some other source of oxygen, such as the nitrous oxide used in these experiments. Dealing with a powerful oxidizing agent like oxygen, which is notoriously hard to control in chemical reactions, will be another considerable hurdle along the path.

For now, Snyder was both pleased and amazed by the illustrative powers of the sophisticated spectroscopic instrumentation in the Solomon labs that were leveraged for this study. These were invaluable to his understanding of the chemistry and the chemical structures involved in the methane-to-methanol process.

"It's cool how you can get some very powerful atomic-level insight, like the cage effect, from these tools that weren't available to previous generations of chemists," Snyder said.

University of Leuven researchers on this study were Max Bols, Dieter Plessers, Robert Schoonheydt and, Bert F. Sels.