Researchers give yeast a boost to make biofuels from discarded plant matter

The new system streamlines the process of fermenting plant sugar to fuel by helping yeast survive industrial toxins

WHITEHEAD INSTITUTE FOR BIOMEDICAL RESEARCH

Research News

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IMAGE: WHITEHEAD INSTITUTE MEMBER GERALD FINK STANDING IN FRONT OF A FIELD OF THE GRASS MISCANTHUS GIGANTEUS, WHICH IS ANOTHER POTENTIAL SOURCE OF CELLULOSE THAT COULD BE CONVERTED TO ETHANOL.... view more 

CREDIT: PHOTO COURTESY OF FELIX LAM

More corn is grown in the United States than any other crop, but we only use a small part of the plant for food and fuel production; once people have harvested the kernels, the inedible leaves, stalks and cobs are left over. If this plant matter, called corn stover, could be efficiently fermented into ethanol the way corn kernels are, stover could be a large-scale, renewable source of fuel.

"Stover is produced in huge amounts, on the scale of petroleum," said Whitehead Institute Member and Massachusetts Institute of Technology (MIT) biology professor Gerald Fink. "But there are enormous technical challenges to using them cheaply to create biofuels and other important chemicals."

And so, year after year, most of the woody corn material is left in the fields to rot.

Now, a new study from Fink and MIT chemical engineering professor Gregory Stephanopolous led by MIT postdoctoral researcher Felix Lam offers a way to more efficiently harness this underutilized fuel source. By changing the growth medium conditions surrounding the common yeast model, baker's yeast Saccharomyces cerevisiae, and adding a gene for a toxin-busting enzyme, they were able to use the yeast to create ethanol and plastics from the woody corn material at near the same efficiency as typical ethanol sources such as corn kernels.

Sugarcoating the issue

For years, the biofuels industry has relied on microorganisms such as yeast to convert the sugars glucose, fructose and sucrose in corn kernels to ethanol, which is then mixed in with traditional gasoline to fuel our cars.

Corn stover and other similar materials are full of sugars as well, in the form of a molecule called cellulose. While these sugars can be converted to biofuels too, it's more difficult since the plants hold onto them tightly, binding the cellulose molecules together in chains and wrapping them in fibrous molecules called lignins. Breaking down these tough casings and disassembling the sugar chains results in a chemical mixture that is challenging for traditional fermentation microorganisms to digest.

To help the organisms along, workers in ethanol production plants pretreat high-cellulose material with an acidic solution to break down these complex molecules so yeast can ferment them. A side effect of this treatment, however, is the production of molecules called aldehydes, which are toxic to yeast. Researchers have explored different ways to reduce the toxicity of the aldehydes in the past, but solutions were limited considering that the whole process needs to cost close to nothing. "This is to make ethanol, which is literally something that we burn," Lam said. "It has to be dirt cheap."

Faced with this economic and scientific problem, industries have cut back on creating ethanol from cellulose-rich materials. "These toxins are one of the biggest limitations to producing biofuels at a low cost." said Gregory Stephanopoulos, who is the Willard Henry Dow Professor of Chemical Engineering at MIT.

Lending yeast a helping hand

To tackle the toxin problem, the researchers decided to focus on the aldehydes produced when acid is added to break down tough molecules. "We don't know the exact mechanism by which aldehydes attack microbes, so then the question was, if we don't really know what it attacks, how do we solve the problem?" Lam said. "So we decided to chemically convert these aldehydes into alcohol forms."

The team began looking for genes that specialized in converting aldehydes to alcohols, and landed on a gene called GRE2. They optimized the gene to make it more efficient through a process called directed evolution, and then introduced it into the yeast typically used for ethanol fermentation, Saccharomyces cerevisiae. When the yeast cells with the evolved GRE2 gene encountered aldehydes, they were able to convert them into alcohols by tacking on extra hydrogen atoms.

The resultant high levels of ethanol and other alcohols produced from the cellulose might have posed a problem in the past, but at this point Lam's past research came into play. In a 2015 paper from Lam, Stephanopoulos and Fink, the researchers developed a system to make yeast more tolerant to a wide range of alcohols, in order to produce greater volumes of the fuel from less yeast. That system involved measuring and adjusting the pH and potassium levels in the yeast's growth media, which chemically stabilized the cell membrane.

By combining this method with their newly modified yeast, "we essentially channeled the aldehyde problem into the alcohol problem, which we had worked on before," Lam said. "We changed and detoxified the aldehydes into a form that we knew how to handle."

When they tested the system, the researchers were able to efficiently make ethanol and even plastic precursors from corn stover, miscanthus and other types of plant matter. "We were able to produce a high volume of ethanol per unit of material using our system," Fink said. "That shows that there's great potential for this to be a cost-effective solution to the chemical and economic issues that arise when creating fuel from cellulose-rich plant materials."

Scaling up

Alternative fuel sources often face challenges when it comes to implementing them on a nationwide scale; electric cars, for example, require a nationwide charging infrastructure in order to be a feasible alternative to gas vehicles.

An essential feature of the researchers' new system is the fact that the infrastructure is already in place; ethanol and other liquid biofuels are compatible with existing gasoline vehicles so require little to no change in the automotive fleet or consumer fueling habits. "Right now [the US produces around] 15 billion gallons of ethanol per year, so it's on a massive scale," he said. "That means there are billions of dollars and many decades worth of infrastructure. If you can plug into that, you can get to market much faster."

And corn stover is just one of many sources of high-cellulose material. Other plants, such as wheat straw and miscanthus, also known as silvergrass, can be grown extremely cheaply. "Right now the main source of cellulose in this country is corn stover," Lam said. "But if there's demand for cellulose because you can now make all these petroleum-based chemicals in a sustainable fashion, then hopefully farmers will start planting miscanthus, and all these super dense straws."

In the future, the researchers hope to investigate the potential of modifying yeasts with these anti-toxin genes to create diverse types of biofuels such as diesel that can be used in typical fuel-combusting engines. "If we can [use this system for other fuel types], I think that would go a huge way toward addressing sectors such as ships and heavy machinery that continue to pollute because they have no other electric or non-emitting solution," Lam said.

CAPTION

In a new paper, researchers present a method to more efficiently produce biofuels from woody plant materials such as corn residues and some grasses.

CREDIT

Markus Distelrath/Pixabay

Engineered yeast could expand biofuels' 

reach

By making the microbes more tolerant to toxic byproducts, researchers show they can use a wider range of feedstocks, beyond corn.

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

Research News

 

CAMBRIDGE, MA - Boosting production of biofuels such as ethanol could be an important step toward reducing global consumption of fossil fuels. However, ethanol production is limited in large part by its reliance on corn, which isn't grown in large enough quantities to make up a significant portion of U.S. fuel needs.

To try to expand biofuels' potential impact, a team of MIT engineers has now found a way to expand the use of a wider range of nonfood feedstocks to produce such fuels. At the moment, feedstocks such as straw and woody plants are difficult to use for biofuel production because they first need to be broken down to fermentable sugars, a process that releases numerous byproducts that are toxic to yeast, the microbes most commonly used to produce biofuels.

The MIT researchers developed a way to circumvent that toxicity, making it feasible to use those sources, which are much more plentiful, to produce biofuels. They also showed that this tolerance can be engineered into strains of yeast used to manufacture other chemicals, potentially making it possible to use "cellulosic" woody plant material as a source to make biodiesel or bioplastics.

"What we really want to do is open cellulose feedstocks to almost any product and take advantage of the sheer abundance that cellulose offers," says Felix Lam, an MIT research associate and the lead author of the new study.

Gregory Stephanopoulos, the Willard Henry Dow Professor in Chemical Engineering, and Gerald Fink, the Margaret and Herman Sokol Professor at the Whitehead Institute of Biomedical Research and the American Cancer Society Professor of Genetics in MIT's Department of Biology, are the senior authors of the paper, which appears today in Science Advances.

Boosting tolerance

Currently, around 40 percent of the U.S. corn harvest goes into ethanol. Corn is primarily a food crop that requires a great deal of water and fertilizer, so plant material known as cellulosic biomass is considered an attractive, noncompeting source for renewable fuels and chemicals. This biomass, which includes many types of straw, and parts of the corn plant that typically go unused, could amount to more than 1 billion tons of material per year, according to a U.S. Department of Energy study -- enough to substitute for 30 to 50 percent of the petroleum used for transportation.

However, two major obstacles to using cellulosic biomass are that cellulose first needs to be liberated from the woody lignin, and the cellulose then needs to be further broken down into simple sugars that yeast can use. The particularly aggressive preprocessing needed generates compounds called aldehydes, which are very reactive and can kill yeast cells.

To overcome this, the MIT team built on a technique they had developed several years ago to improve yeast cells' tolerance to a wide range of alcohols, which are also toxic to yeast in large quantities. In that study, they showed that spiking the bioreactor with specific compounds that strengthen the membrane of the yeast helped yeast to survive much longer in high concentrations of ethanol. Using this approach, they were able to improve the traditional fuel ethanol yield of a high-performing strain of yeast by about 80 percent.

In their new study, the researchers engineered yeast so that they could convert the cellulosic byproduct aldehydes into alcohols, allowing them to take advantage of the alcohol tolerance strategy they had already developed. They tested several naturally occurring enzymes that perform this reaction, from several species of yeast, and identified one that worked the best. Then, they used directed evolution to further improve it.

"This enzyme converts aldehydes into alcohols, and we have shown that yeast can be made a lot more tolerant of alcohols as a class than it is of aldehydes, using the other methods we have developed," Stephanopoulos says.

Yeast are generally not very efficient at producing ethanol from toxic cellulosic feedstocks; however, when the researchers expressed this top-performing enzyme and spiked the reactor with the membrane-strengthening additives, the strain more than tripled its cellulosic ethanol production, to levels matching traditional corn ethanol.

Abundant feedstocks

The researchers demonstrated that they could achieve high yields of ethanol with five different types of cellulosic feedstocks, including switchgrass, wheat straw, and corn stover (the leaves, stalks, and husks left behind after the corn is harvested).

"With our engineered strain, you can essentially get maximum cellulosic fermentation from all these feedstocks that are usually very toxic," Lam says. "The great thing about this is it doesn't matter if maybe one season your corn residues aren't that great. You can switch to energy straws, or if you don't have high availability of straws, you can switch to some sort of pulpy, woody residue."

The researchers also engineered their aldehyde-to-ethanol enzyme into a strain of yeast that has been engineered to produce lactic acid, a precursor to bioplastics. As it did with ethanol, this strain was able to produce the same yield of lactic acid from cellulosic materials as it does from corn.

This demonstration suggests that it could be feasible to engineer aldehyde tolerance into strains of yeast that generate other products such as diesel. Biodiesels could potentially have a big impact on industries such as heavy trucking, shipping, or aviation, which lack an emission-free alternative like electrification and require huge amounts of fossil fuel.

"Now we have a tolerance module that you can bolt on to almost any sort of production pathway," Stephanopoulos says. "Our goal is to extend this technology to other organisms that are better suited for the production of these heavy fuels, like oils, diesel, and jet fuel."

###

The research was funded by the U.S. Department of Energy and the National Institutes of Health.

Written by Anne Trafton, MIT News Office

 

Texan voters unsure if state can tackle power grid issues

Latest survey shows Texan voters want weatherization/winterization of electric grid but doubt legislated policy will deliver

UNIVERSITY OF HOUSTON

Research News

 

When Winter Storm Uri hit, many Texans lost power from February 14-20, resulting in losses of lives and economic activity, and damages to their homes that for some are still not completely repaired. Now, four months later as demand for electricity has increased at the start of the summer amid tight supply, Texans continue to prioritize improvements to the power grid, albeit with doubt as to whether the Texas Legislature and Governor can get the job done.

In a survey by the Hobby School of Public Affairs and UH Energy at the University of Houston fielded between May 13-24, 1,500 individuals in Texas aged 18 and older responded to a series of questions regarding their experience during Winter Storm Uri and their evaluation of policy proposals toward protecting the Texas electric grid from severe weather events in the future.

"Winter Storm Uri was a massive event, with widespread impact across the state" said Pablo M. Pinto, the principal investigator who serves as associate professor and director of the Center for Public Policy at the University of Houston's Hobby School of Public Affairs.

Two-thirds of those surveyed lost power following Winter Storm Uri, while roughly 30% of those surveyed sustained damage to their home. Additionally, the bulk of power outages for sustained periods of time were clustered near larger urban centers in Texas.

Larger urban centers had no power for more than 30 hours in several zip codes. According to the survey, in the Houston area these zip codes were more clustered than the other large metro-areas in Texas.

The impact of the February storm is abundantly clear, but Texans' confidence in the ability of their state government to prevent another incident like this from repeating itself is less clear.

"Three months after the storm, Texans remained frustrated and blamed government officers, power generators and natural gas producers for the power outages," Pinto said. "They signal this frustration in their demand that energy producers and the Texas governments, not consumers, should bear the costs of retrofitting the Texas grid to withstand extreme weather events, at least in the short term."

Roughly 40% of respondents disagreed that the Texas state government will adequately tackle issues related to the electric grid. A partisan and age divide emerged within this result, namely that Republicans agreed more than Democrats and Independents, as did respondents older than 65 years old.

"A salient concern among Texans is having access to a reliable supply of electric power, which means a power system to provide uninterrupted service at an acceptable price," said Sunny Wong, professor at the UH Hobby School of Public Affairs and one of the principal investigators of the study.

The survey showed a correlation between age and disapproval of unreliable electric service. Of those aged 45-65 years old and older than, 48% and 53%, respectively, agreed that it is never acceptable for the power to go out.

Despite some doubt, eligible voters across party lines believe that wind, solar and other renewable energy sources will make a substantial contribution to reliable and secure electricity supply in Texas in the future. Sun or solar power accounted for 56.3% of surveyed respondents selected sun or solar power as a likely to make a substantial contribution, followed by wind power at 54%. The greatest support for renewables came from ages 18-29 at 69%.

"Even among Republicans, who had the lowest level of support compared to Democrats and Independents, 42% still agreed that solar power would make a substantial contribution," said Gail Buttorff, Co-Director, Survey Research Institute and Assistant Instructional Professor, at the UH Hobby School of Public Affairs and co-principal investigator.

"Younger respondents are much more likely to believe that climate change is happening, though a majority of respondents believe it is happening across age groups. 91% of respondents aged 18-29 believe climate change is happening compared to 76%, 73%, and 60% in the three older age groups."

With so many affected by the storm in February 2021 and the recent request by ERCOT to conserve energy in light of supply tightness juxtaposed by increased demand for electricity to cool homes, Texans continue to keep the power grid at the forefront of their minds.

Senate Bills 2 and 3 were passed by the Texas Legislature in an effort to oversee the appointment of the Public Utility Commission of Texas and of Electric Reliability Council of Texas (ERCOT), as well as require the weatherization of some of the industry's and infrastructure. These both fall in line with voter values, which point to reliability (40%) as a top priority, followed by cost (26%). Weatherization and winterization of the electricity system also emerged as top policy preference among respondents.

"Although respondents preferred not to see the price of electricity increase, they realize that reliable access to electricity will require major investments and regulatory changes in the long run" said Ramanan Krishnamoorti, Chief Energy Officer at the University of Houston and Professor of Chemical and Biomolecular Engineering, who was one of the leaders of the study. "When offered a menu of investments and policy interventions, respondents revealed their willingness to pay modest increases in electricity prices to shorten power."

Time will tell whether legislation passed in the Spring will satiate Texas voters' demands for more reliable and affordable electricity. One point is certain, a majority of surveyed voters have pointed to renewables as a preferred path forward in Texas for diversifying the energy mix and improving reliable and sustainable electricity. Texas is the leading state in wind power already and among the top leaders in solar, and it appears Texas voters are in agreement to continue leading the pack.

Hydrofracking environmental problems not that different from conventional drilling

SYRACUSE UNIVERSITY

Research News

IMAGE: PROFESSOR TAO WEN CONTRIBUTED TO A STUDY ASSESSING GROUNDWATER CONTAMINATION CAUSED BY OIL AND GAS PRODUCTION. view more 

CREDIT: SYRACUSE UNIVERSITY

Crude oil production and natural gas withdrawals in the United States have lessened the country's dependence on foreign oil and provided financial relief to U.S. consumers, but have also raised longstanding concerns about environmental damage, such as groundwater contamination.

A researcher in Syracuse University's College of Arts and Sciences, and a team of scientists from Penn State, have developed a new machine learning technique to holistically assess water quality data in order to detect groundwater samples likely impacted by recent methane leakage during oil and gas production. Using that model, the team concluded that unconventional drilling methods like hydraulic fracturing - or hydrofracking - do not necessarily incur more environmental problems than conventional oil and gas drilling.

The two common ways to extract oil and gas in the U.S. are through conventional and unconventional methods. Conventional oil and gas are pumped from easily accessed sources using natural pressure. Conversely, unconventional oil and gas are acquired from hard-to-reach sources through a combination of horizontal drilling and hydraulic fracturing. Hydrofracking extracts natural gas, petroleum and brine from bedrock formations by injecting a mixture of sand, chemicals and water. By drilling into the earth and directing the high-pressure mixture into rock, the gas inside releases and flows out to the head of a well.

Tao Wen, assistant professor of earth and environmental sciences (EES) at Syracuse, recently led a study comparing data from different states to see which method might result in greater contamination of groundwater. They specifically tested levels of methane, which is the primary component of natural gas.

The team selected four U.S. states located in important shale zones to target for their study: Pennsylvania, Colorado, Texas and New York. One of those states - New York - banned the practice of hydrofracking in 2015 following a review by the NYS Department of Health which found significant uncertainties about health, including increased water and air pollution.

Wen and his colleagues compiled a large groundwater chemistry dataset from multiple sources including federal agency reports, journal articles, and oil and gas companies. The majority of tested water samples in their study were collected from domestic water wells. Although methane itself is not toxic, Wen says that methane contamination detected in shallow groundwater could be a risk to the relevant homeowner as it could be an explosion hazard, could increase the level of other toxic chemical species like manganese and arsenic, and would contribute to global warming as methane is a greenhouse gas.

Their model used sophisticated algorithms to analyze almost all of the retained geochemistry data in order to predict if a given groundwater sample was negatively impacted by recent oil and gas drilling.

The data comparison showed that methane contamination cases in New York - a state without unconventional drilling but with a high volume of conventional drilling - were similar to that of Pennsylvania - a state with a high volume of unconventional drilling. Wen says this suggests that unconventional drilling methods like fracking do not necessarily lead to more environmental problems than conventional drilling, although this result might be alternatively explained by the different sizes of groundwater chemistry datasets compiled for these two states.

The model also detected a higher rate of methane contamination cases in Pennsylvania than in Colorado and Texas. Wen says this difference could be attributed to different practices when drillers build/drill the oil and gas wells in different states. According to previous research, most of the methane released into the environment from gas wells in the U.S. occurs because the cement that seals the well is not completed along the full lengths of the production casing. However, no data exists to conclude if drillers in those three states use different technology. Wen says this requires further study and review of the drilling data if they become available.

According to Wen, their machine learning model proved to be effective in detecting groundwater contamination, and by applying it to other states/counties with ongoing or planned oil and gas production it will be an important resource for determining the safest methods of gas and oil drilling.

CAPTION

Shaded areas indicate some of those major regions producing natural gas in the U.S. In this study, researchers select four U.S. states to study that are located within important shale zones including the famous and prolific shale play - Marcellus.

CREDIT

Syracuse University

Wen and his colleagues from Penn State, including Mengqi Liu, a graduate student from the College of Information Sciences and Technology, Josh Woda, a graduate student from Department of Geosciences, Guanjie Zheng, former Ph.D. student from the College of Information Sciences and Technology, and Susan L. Brantley, distinguished professor in the Department of Geosciences and director of Earth and Environmental Systems Institute, recently had their findings published in the journal Water Research.

Advancing research on environmentally friendly, hydrogen-enriched fuel

Texas A&M researchers study the capabilities of hydrogen-enriched fuel in spark ignition engines

TEXAS A&M UNIVERSITY

Research News

 

As you drive down the highway, you may notice an increasing number of hybrid and electric vehicles. Alternative energy automobiles are on the rise contributing to the global effort to reduce carbon emissions. As we move together down this road, researchers are looking to determine new solutions to this ongoing problem.

Dr. Muzammil Arshad, instructional assistant professor for the Department of Multidisciplinary Engineering at Texas A&M University, and a team of multidisciplinary student researchers conducted a study to analyze the performance of hydrogen-enriched fuel on spark engine performance and efficiency. This solution could make significant contributions to helping automobiles become more environmentally friendly.

"Due to climate change as well as a focus on reduced emissions and deprivation of fossil fuel reserves, there has been immense research to reduce emissions," said Arshad. "This has led to investigating effects of dual fuels on the emissions as well as engine performance parameters because we don't want to lose the combustion characteristics by injecting a secondary fuel."

Two multidisciplinary students, Jonathan Rodriguez and Miriam Alanis, contributed significantly and are co-authors of the research. As undergraduate students at the Higher Education Center at McAllen (HECM), this accomplishment is an impactful stepping stone.

Their research was accepted into the 12th U.S. Annual Combustion Meeting hosted in College Station, where they presented their findings.

"I think presenting at the conference was wonderful," said Alanis. "From the study, we were able to produce tangible results that could potentially be meaningful and useful."

This study was also recently published in the Petroleum and Chemical Industry International journal.

"These accolades establish our research and give it credibility," said Rodriguez. "We are making progress at the HECM. I believe we are part of the first student research project conducted on campus. As an undergraduate, I didn't believe it was an experience I would achieve until Dr. Arshad developed the project."

Spark ignition engines are commonly used in various small SUVs and sedans. In these engines, gasoline merges with air and is ignited by a spark formed by the spark plug, creating combustion. The car can convert thermal energy into kinetic by burning the fuel, allowing the car to move.

"We have performed numerical simulations to understand and predict the performance of spark ignition engines by introducing hydrogen in various quantities and predicting the effect on various efficiencies, in-cylinder pressure and emissions," said Arshad.

The goal is that by adding hydrogen, the car will be more fuel-efficient and produce less harmful emissions. The researchers also analyzed whether significant changes would be required to current spark ignition engines to account for the addition of hydrogen.

"Originally, we thought the difference in the in-cylinder pressure due to the enrichment could create issues that would require major modifications to the engine," said Rodriguez. "Our findings show a reduction in the in-cylinder peak pressure, consequently insinuating that we do not need major modifications to the engine to use this dual fuel. This research has potential value in the fuel market while leaving the vehicle market untouched."

As the first research initiative at the HECM, Arshad is thrilled with the results and plans to conduct similar projects with students in the future.

"Research experience and publications are a major skill they can now showcase on their resumes," said Arshad. "They also learned skills such as time management, working under pressure, meeting deadlines and presenting in front of large audiences. All of these skills are valuable and will help them in the future."

New report highlights best practices for sustainable rural infrastructure

Low-volume rural roads provide critical services, but require extensive planning to prevent detrimental effects on air, water and wildlife

ECOLOGICAL SOCIETY OF AMERICA

Research News

 

Interstate highway systems and networks of dense urban roads typically receive top billing on maps, in infrastructure legislation and in travelers' daily commuting routes. However, more than 80% of all US roads are considered low-volume roads - defined as those that carry fewer than 1000 vehicles per day. According to a new report published by the Ecological Society of America, "The Ecology of Rural Roads: Effects, Management and Research," this less-traveled road network can have an outsized impact on surrounding ecosystems, altering the local hydrology, affecting wildlife populations and shuttling invasive species into new areas.

"Rural roads provide important transportation connections for rural populations but, while apparently innocuous, can lead to drastic changes in whole landscapes, including the plants and animals that live in them," said Alisa W. Coffin, a research ecologist at the United States Department of Agriculture's Agricultural Research Service Southeast Watershed Research Laboratory in Tifton, GA.

Proper planning and maintenance of rural roads improves farmers' ability to get products to market, creating more reliable conditions for agricultural trade and for other social and economic opportunities. Maintaining and improving rural infrastructure is important not only for surrounding rural communities, but also for the broader public that depends on the goods and services that these communities produce. However, roads may also introduce heavy metals and road salt into waterways, alter flooding regimes and even change the rate at which nearby trees release water into the atmosphere. Animal deaths from vehicle collisions on rural roads can dramatically alter wildlife populations. When transportation planners fail to account for these cumulative impacts, it compromises the clean water and healthy ecosystems that support the wildlife and people that live nearby.

Road ecology is a relatively new discipline, and Coffin and her colleagues hope their paper can increase awareness of the importance of low-volume rural road networks. The report also describes best management practices and policy applications.

"Transportation authorities are increasingly looking to the science of road ecology for solutions on how to improve our transportation systems while also mitigating for their negative ecological effects," said Coffin. "The science shows that new roads bring additional negative effects and that mitigation improves ecological outcomes."

The report is No. 23 in Issues in Ecology, a series of reports published by the Ecological Society of America that use commonly understood language to present the consensus of a panel of scientific experts on issues related to the environment. Previous reports in the series are available at https://www.esa.org/publications/issues/.

Report:
Coffin, Alisa, et al. 2020. "The Ecology of Rural Roads: Effects, Management, and Research." Issues in Ecology 23. https://www.esa.org/wp-content/uploads/2021/06/IIE_24-Rural-Roads.pdf

Author contact:
Alisa W. Coffin (alisa.coffin@usda.gov)

Authors:

• Alisa W. Coffin, Southeast Watershed Research Laboratory, USDA Agricultural Research Service, Tifton, GA
• Douglas S. Ouren, Emeritus, Fort Collins Science Center, US Geological Survey, Fort Collins, CO, USA
• Neil D. Bettez, Cary Institute of Ecosystem Studies, Millbrook, NY
• Luís Borda-de-Água, CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos Genéticos, Laboratório Associado, Universidade do Porto, Campus Agrário de Vairão, Vairão, Portugal; CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos Genéticos, Laboratório Associado, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, Lisbon, Portugal
• Amy E. Daniels, Independent Consultant, Rua Mondlane, Luanda, Angola
• Clara Grilo, CESAM - Centre for Environmental and Marine Studies, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
• Jochen A.G. Jaeger, Concordia University Montreal, Department of Geography, Planning and Environment, Montreal, Quebec, Canada
• Laetitia M. Navarro, German Center for Integrative Biodiversity Research, Leipzig, Germany
• Haiganoush K. Preisler, (Retired), Pacific Southwest Research Station, USDA Forest Service, Albany, CA
• Emily S.J. Rauschert, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH

The Ecological Society of America, founded in 1915, is the world's largest community of professional ecologists and a trusted source of ecological knowledge, committed to advancing the understanding of life on Earth. The 9,000 member Society publishes five journals and a membership bulletin and broadly shares ecological information through policy, media outreach, and education initiatives. The Society's Annual Meeting attracts 4,000 attendees and features the most recent advances in ecological science. Visit the ESA website at https://www.esa.org.

ESA is offering complimentary registration at the 106th Annual Meeting of the Ecological Society of America for press and institutional public information officers (see credential policy). The all-virtual meeting will feature live plenaries, panels and Q&A sessions from August 2-6, 2021. To apply for press registration, please contact ESA Public Information Manager Heidi Swanson at heidi@esa.org.

Issues in Ecology is an official publication of ESA, using commonly understood language to report the consensus of a panel of scientific experts on issues related to the environment. Issues in Ecology aims to build public understanding of the importance of the products and services provided by the environment to society. The text for every Issues in Ecology is reviewed for technical content by external expert reviewers. https://www.esa.org/publications/issues/

 

Natural hazards threaten 57% of US structures

Rising temperatures and risky development contribute to heightened exposure to earthquakes, flooding, tornadoes, hurricanes and wildfire

AMERICAN GEOPHYSICAL UNION

Research News

 

IMAGE: A NEW STUDY FINDS MORE THAN HALF OF THE US BUILT ENVIRONMENT IS AT RISK OF IMPACT FROM NATURAL HAZARDS, LARGELY DUE TO DEVELOPMENT IN HOTSPOTS OF HIGH EXPOSURE TO... view more 

CREDIT: INGLESIAS ET AL. (2021) EARTH'S FUTURE https://doi.org/10.1029/2020EF001795...

WASHINGTON--More than half of the structures in the contiguous United States are exposed to potentially devastating natural hazards--such as floods, tornadoes and wildfires--according to a new study in the AGU journal Earth's Future, which publishes interdisciplinary research on the past, present and future of our planet and its inhabitants.

Increasing temperatures and environmental changes contribute to this trend, and the research also shines the light on another culprit: the way humans develop open land, towns and cities.

"We know that climate change is increasing the risk of damage from some natural hazards," said Virginia Iglesias, a research scientist with the University of Colorado Boulder Earth Lab and lead author of the paper. "But are losses also increasing because of the way that we are developing our cities, our towns?"

Yes, the new analysis found. To evaluate the impact of development on natural hazard risk, Iglesias and her colleagues built maps of earthquake, flood, hurricane, tornado and wildfire hazards and compared them to a unique dataset of historical land-use derived from Zillow's housing and property database. The team identified natural hazard "hotspots" by mapping where the probability or magnitude of an individual natural hazard event fell in the top 10 percent.

"Since development patterns drive exposure and loss, more detailed mapping can improve national-scale risk assessments," Iglesias said. "This study fills a gap by exploring changes in hazard exposure across the country, at fine resolution, for multiple hazards, and over long periods."

The study shows that 57% of the structures in the contiguous United States are in natural hazard hotspots; these hotspots make up only about a third of the total land. About 1.5 million structures are in hotspots of two or more natural hazards. Despite a national slowdown in development over the last decade, the number of structures in natural hazard hotspots is still increasing, the authors found.

In some hotspots, people have built protections like levees and floodwalls, the authors noted in the new assessment. This becomes an interesting question for further research: can that infrastructure protect properties from hazardous events in the future?

The study also investigated regional development patterns that affect hazard risk. In hurricane and earthquake hotspots, for example, the primary driver for an increase in risk was the fact that people were adding buildings, homes, and other structures to already developed areas in cities and suburbs. In wildfire, flood, and tornado hotspots, it was the expansion of new buildings in rural areas and wildlands that increased risk of damage.

Iglesias and her colleagues suggest that local decision makers could use the methods innovated in this study to improve risk assessments in their purview and to better understand the socio-economic variables that might increase the risk exposure of neighborhoods or communities.

"Vulnerability matters. There's evidence that natural disasters exacerbate socioeconomic inequality," Iglesias said. "If we want to make decisions that effectively increase the ability of communities to cope with natural hazards, we need to know where vulnerable populations live, and the specific hazards they're exposed to."

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AGU (http://www.agu.org) supports 130,000 enthusiasts to experts worldwide in Earth and space sciences. Through broad and inclusive partnerships, we advance discovery and solution science that accelerate knowledge and create solutions that are ethical, unbiased and respectful of communities and their values. Our programs include serving as a scholarly publisher, convening virtual and in-person events and providing career support. We live our values in everything we do, such as our net zero energy renovated building in Washington, D.C. and our Ethics and Equity Center, which fosters a diverse and inclusive geoscience community to ensure responsible conduct.

Notes for Journalists:

This research study is open access. Download a PDF copy of the paper here. Neither the paper nor this press release is under embargo.

Paper title: "Risky development: Increasing exposure to natural hazards in the United States"

Authors:

• Virginia Iglesias, Anna E. Braswell, Matthew W. Rossi, Maxwell B. Joseph: Earth Lab, Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado, USA;
• Caitlin McShane: Department of Geography, University of Colorado, Boulder, Colorado, USA;
• Megan Cattau: Human? Environment Systems, Boise State University, Boise, Idaho, USA;
• Michael J. Koontz, Joe McGlinchy, R. Chelsea Nagy: Earth Lab, Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado, USA;
• Jennifer Balch: Earth Lab, Cooperative Institute for Research in Environmental Sciences (CIRES), and Department of Geography, University of Colorado, Boulder, Colorado, USA;
• Stefan Leyk: Earth Lab, Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado, USA;
• William R. Travis: Earth Lab, Cooperative Institute for Research in Environmental Sciences (CIRES), and Department of Geography, University of Colorado, Boulder, Colorado, USA.

Compost improves apple orchard sustainability

AMERICAN SOCIETY OF AGRONOMY

Research News

 

IMAGE: APPLE TREES IN COMMERCIAL ORCHARDS ARE GRAFTED PLANTS. THE ABOVE-GROUND PORTION OF THE DESIRED APPLE TREE IS ATTACHED TO A HEALTHY ROOT SYSTEM. HERE, RESEARCHER GREG PECK HARVESTS APPLE ROOTS.... view more 

CREDIT: GREG PECK

As the saying goes, an apple a day keeps the doctor away. But what's the key to growing a quality apple?

Apple trees need access to important nutrients, which come from the soil. However, soil is quite different from orchard to orchard.

Gregory Peck studies how sustainable orchard practices can improve the availability of nutrients. The research was recently shared in Soil Science Society of America Journal, a publication of the Soil Science Society of America.

Farmers are becoming more aware of the environmental impacts of different orchard management practices.

"Apple growers are interested in developing more sustainable nutrient management plans," explains Peck. "They are asking for more information to improve the soil health on their farms."

A healthy soil depends on many factors. One of those factors is the microbial community living in the soil. The community is made up of bacteria, nematodes, and fungi. Some of these microbes convert nutrients in the soil into forms that apple trees can use.

In the soil, microbes and plant roots interact in beneficial partnerships. Plants, like apple trees, release fluids from their roots into the soil. These fluids serve as a food source for the microbial community. In return, the microbes can help the apple trees.

"Bacteria serve many functions in an apple orchard soil," says Peck. "They recycle nutrients, promote plant growth, and even alter plant metabolisms."

In this study, the team applied composts - such as chicken litter and yard waste - to apple orchards.

Researchers found that adding compost increased the number of soil bacteria associated with recycling nutrients. The compost provides additional food for the bacteria to help them thrive.

This larger microbial community means more nutrients are available to the apple trees.

By applying compost, farmers could reduce the amount of fertilizer needed to provide nutrients for apple trees. This could help their pocketbooks and the environment.

Some fertilizers come from non-renewable sources. Adding in compost to a farm's nutrient management plan reduces the dependence on those sources. It also provides a sustainable use for materials otherwise considered to be waste.

On a practical level, this research shows that farmers can successfully integrate compost with quicker release fertilizer sources.

"Although sustainable apple production is not defined by a single practice, we think this research contributes to the long-term goal of increasing farm sustainability," says Peck.

In the future, the team hopes to replicate this study in different regions with different soil characteristics. They would also like to take a deeper look into the roles of fungi in the microbial community of orchard soils.

"We can produce great apples, and apple orchard farmers can supply a huge population with delicious, nutritious food," Peck adds.

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Gregory Peck is a researcher at Cornell University. This work was supported by Cornell University - College of Agriculture and Life Science, the Virginia Agricultural Council, the Virginia Apple Research Program, the Virginia Agricultural Experiment Station, and Virginia Tech - Department of Horticulture.

CAPTION

The research team used pots to ensure uniformity in the soil prior to planting the trees and adding the fertilizer treatments.

CREDIT

Greg Peck

CAPTION

Researchers air-dried harvested apple roots. The roots were further dried in an oven to measure biomass.

CREDIT

Greg Peck

Mining precious rare-earth elements from coal fly ash with a reusable ionic liquid

AMERICAN CHEMICAL SOCIETY

Research News

 

Rare-earth elements are in many everyday products, such as smart phones, LED lights and batteries. However, only a few locations have large enough deposits worth mining, resulting in global supply chain tensions. So, there's a push toward recycling them from non-traditional sources, such as waste from burning coal -- fly ash. Now, researchers in ACS' Environmental Science & Technology report a simple method for recovering these elements from coal fly ash using an ionic liquid.

While rare-earth elements aren't as scarce as their name implies, major reserves are either in politically sensitive locations, or they are widely dispersed, which makes mining them challenging. So, to ensure their supply, some people have turned to processing other enriched resources. For instance, the ash byproduct from coal-fired power plants has similar elemental concentrations to raw ores. Yet, current methods to extract these precious materials from coal fly ash are hazardous and require several purification steps to get a usable product. A potential solution could be ionic liquids, which are considered to be environmentally benign and are reusable. One in particular, betainium bis(trifluoromethylsulfonyl)imide or [Hbet][Tf2N], selectively dissolves rare-earth oxides over other metal oxides. This ionic liquid also uniquely dissolves into water when heated and then separates into two phases when cooled. So, Ching-Hua Huang, Laura Stoy and colleagues at Georgia Tech wanted to see if it would efficiently and preferentially pull the desired elements out of coal fly ash and whether it could be effectively cleaned, creating a process that is safe and generates little waste.

The researchers pretreated coal fly with an alkaline solution and dried it. Then, they heated ash suspended in water with [Hbet][Tf2N], creating a single phase. When cooled, the solutions separated. The ionic liquid extracted more than 77% of the rare-earth elements from fresh material, and it extracted an even higher percentage (97%) from weathered ash that had spent years in a storage pond. Finally, rare-earth elements were stripped from the ionic liquid with dilute acid. The researchers found that adding betaine during the leaching step increased the amounts of rare-earth elements extracted. The team tested the ionic liquid's reusability by rinsing it with cold water to remove excess acid, finding no change in its extraction efficiency through three leaching-cleaning cycles. The researchers say that this low-waste approach produces a solution rich in rare-earth elements, with limited impurities, and could be used to recycle precious materials from the abundance of coal fly ash held in storage ponds.

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The authors acknowledge funding from the National Science Foundation Graduate Research Fellowship, the Georgia Power Fellowship hosted by the Georgia Institute of Technology and the Environmental Research & Education Foundation.

The paper's abstract will be available on June 23 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acs.est.1c00630

The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS' mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and all its people. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world's scientific knowledge. ACS' main offices are in Washington, D.C., and Columbus, Ohio.

Rising greenhouse gases pose continued threat to Arctic ozone layer

New study shows climate change is increasing ozone depletion over the Arctic

UNIVERSITY OF MARYLAND

Research News

 

IMAGE: STRATOSPHERIC CLOUDS ABOVE THE ARCTIC, LIKE THOSE SEEN HERE OVER KIRUNA, SWEDEN, PROVIDE IDEAL CONDITIONS FOR CHEMICAL REACTIONS THAT TRANSFORM CHLORINE TO A FORM THAT DEPLETES THE EARTH'S PROTECTIVE OZONE... view more 

CREDIT: ROSS SALAWITCH/UMD

There is a race going on high in the atmosphere above the Arctic, and the ozone layer that protects Earth from damaging ultraviolet (UV) radiation will lose the race if greenhouse gas emissions aren't reduced quickly enough.

A new study from an international team of scientists, including University of Maryland Professor Ross Salawitch, shows that extremely low winter temperatures high in the atmosphere over the arctic are becoming more frequent and more extreme because of climate patterns associated with global warming. The study also shows that those extreme low temperatures are causing reactions among chemicals humans pumped into the air decades ago, leading to greater ozone losses.

The new findings call into question the commonly held assumption that ozone loss would grind to a halt in just a few decades following the 2010 global ban on the production of ozone depleting chemicals called chlorofluorocarbons (CFCs) and halons.

The study--which was jointly conducted by UMD, the Alfred Wegener Institute's Helmholtz Centre for Polar and Marine Research, and the Finnish Meteorological Institute--was published in the journal Nature Communications on June 23, 2021.

"We're in a kind of race between the slow and steady decline in CFCs, which take 50 to 100 years to go away, and climate change, which is causing polar vortex temperature extremes to become colder at a rapid pace," said Ross Salawitch, who is a professor in the UMD Department of Atmospheric and Oceanic Science, the Department of Chemistry and Biochemistry, and the Earth System Science Interdisciplinary Center. "The increasingly cold temperatures create conditions that promote ozone depletion by CFCs. So, even though these compounds are slowly going away, Arctic ozone depletion is on the rise as the climate changes."

New data from the study showed the lowest Arctic polar vortex temperatures and the highest ozone losses on record in 2020, beating the previous records set nine years ago in 2011.

The polar vortex is a relatively self-contained, low-pressure system that forms in the stratosphere--at an altitude of about 12 to 50 kilometers (7.5 to 31 miles)--over the Arctic every autumn and stays for varying durations throughout the winter to spring. The pattern of warm and cold winter temperatures in the polar vortex is very irregular, so not every winter is extremely cold.

But the trend toward more frequent and more extreme low temperatures in the polar vortex concerns the researchers, because those conditions promote the formation of clouds, and that promotes ozone loss in the polar stratosphere.

Most of the chlorine and a significant amount of the bromine in the stratosphere comes from the breakdown of CFCs, halons and other ozone-depleting substances. Normally within the Arctic polar vortex the chlorine is non-reactive, but clouds provide the right conditions for the chlorine to change form and react with bromine and sunlight to destroy ozone.

Despite drastic reduction of the industrial production of CFCs and halons since the Montreal Protocol in 1987 and the global ban that followed in 2010, these long-lasting compounds are still abundant in the atmosphere. According to the World Meteorological Organization, atmospheric chlorine and bromine produced by humans is not expected to fall below 50% of their highest levels until the end of this century.

To determine what this situation means for the future, the researchers projected ozone loss out to the year 2100 based on the long-term temperature trend in the polar vortex and the expected decline in chlorine and bromine compounds. They based their predictions on the output from 53 top climate models used by the Intergovernmental Panel on Climate Change.

"All but one of the climate models we looked at show that exceptionally cold winters in the polar vortex will get colder over time," Salawitch said. "And the more greenhouse gas emissions there are, the steeper the trend, which means greater ozone depletion."

Combining these projections with analyses of meteorological data from the past 56 years, the researchers confirmed that the Arctic is already experiencing a significant trend toward lower stratospheric temperatures and associated increases in ozone losses. What's more, their observations reveal that these trends are occurring at rate consistent with the fastest climate models.

"We have been saying that a train is coming for a number of years now," said Salawitch, pointing to research papers he published in 2004 and 2006 that showed extreme winters in the Arctic were becoming colder. "We've now seen the train whizzing by with record ozone loss in 2011 and now in 2020. So, this paper is really a wake-up call that something is happening in the atmosphere that's really important for ozone, and it looks like greenhouse gases are driving it."

Salawitch and his colleagues do not yet fully understand how increasing greenhouse gas emissions and the associated changes to global climate are causing the extreme cold winters in the stratospheric layer of the polar vortex. But some of the underlying mechanisms are understood. Global warming occurs in part because greenhouse gases trap heat closer to Earth's surface, which allows cooling of the upper layers in the stratosphere, where the ozone layer is located. Warming at the surface causes changes to prevailing wind patterns, and the researchers suggest that these changes also produce lower temperatures in the polar vortex.

The researchers also note that recent years have seen a rapid increase in methane, a more powerful greenhouse gas than carbon dioxide, in the lower atmosphere. As this gas travels to the stratosphere, it increases humidity, which also leads to conditions that promote ozone-destroying chemical reactions in the Arctic.

Because ozone filters much of the sun's potentially harmful UV radiation, a depleted ozone layer over the Arctic can result in more UV radiation reaching the surface of the Earth over Europe, North America and Asia when the polar vortex dips south.

But there is hope for avoiding future ozone depletion, according to the researchers. Their study shows that substantial reductions in greenhouse gas emissions over the coming decades could lead to a steady decline in conditions that favor large ozone loss in the Arctic stratosphere.

The research paper, Climate change favours large seasonal loss of Arctic ozone, Peter von der Gathen, Rigel Kivi, Ingo Wohltmann, Ross J. Salawitch, Markus Rex, was published in the journal Nature Communications on June 23, 2021.

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This work was supported by NASA's Atmospheric Composition and Modeling Program (Award No. 80NSSC19K0983) and the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The content of this article does not necessarily reflect the views of these organizations.

Media Relations Contact: Kimbra Cutlip, 301-405-9463, kcutlip@umd.edu

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