The study, “Bioenergy sorghum’s deep roots: A key to sustainable biomass production on annual cropland,” was recently published in GCB Bioenergy.

According to the research, bioenergy sorghum hybrids capture and sequester significant amounts of atmospheric carbon dioxide in soil. The crop can improve soil fertility and potentially earn carbon credits to offset greenhouse gas emissions.

In addition, the study shows that bioenergy sorghum’s unusually deep root system can reach sources of water and nutrients untapped by other annual crops. These results suggest the crop can help manage fertilizer runoff from other annuals in a crop rotation.

The senior investigator for the work is John Mullet, Ph.D., professor and Perry L. Adkisson Chair in Agricultural Biology in the Department of Biochemistry and Biophysics. A key collaborator is Bill Rooney, Ph.D., professor and Borlaug-Monsanto Chair for Plant Breeding and International Crop Improvement, Department of Soil and Crop Sciences. Both are in the Texas A&M College of Agriculture and Life Sciences, Bryan-College Station.

The U.S. Department of Energy Great Lakes Bioenergy Research Center and the Advanced Research Projects Agency-Energy funded the project.

Texas A&M-bred annual bioenergy crop

Mullet is an expert in bioenergy crops’ genomics, genetics and gene regulatory networks. Rooney spearheaded the development of bioenergy sorghum hybrids over the past 20 years. For the past 15 years, Rooney and Mullet have collaborated to develop bioenergy sorghum.

In fact, Mullet and Rooney have been working to improve bioenergy sorghum varieties to produce an ideal annual bioenergy crop. The hybrid used in the recent study creates high yields of biomass for fuel, power and bioproduct generation. The crop also has excellent drought resilience, good nitrogen-use efficiency and a deep root system.

“There is an assumption that the most sustainable bioenergy crops are perennial because they require fewer inputs and can sequester more biomass than annuals,” Rooney said. “Those statements are true, but U.S. agriculture always requires annual cropping varieties and options as well.”

New benchmark for carbon credit modeling, soil fertility

The study shows that an acre planted with a bioenergy sorghum hybrid accumulates about 3.1 tons of dry root biomass over the crop’s 155-day growing season. Bioenergy sorghum roots also grew to over 6.5 feet deep over their growing season.

These new metrics make it easier to predict how much atmospheric carbon dioxide might be captured inside roots. The numbers can also shed light on how many carbon credits a planted field might earn.

“Frankly, the numbers are quite favorable,” Rooney said.

The numbers are also important for understanding the crop’s potential to improve soil fertility and water-holding capacity by replenishing soil organic carbon. However, previous research has shown that in the U.S., soil organic carbon levels have fallen by 50% over the past 100 years in land planted with annual crops.

This drop in soil carbon levels could be due to cropping practices, microbial activity and changing land use, Rooney said. These complex factors mean that predicting how long it might take to replenish lost carbon requires sophisticated modeling. The restoration process is likely to take many decades.

“For modeling, they need to have a realistic number to start with,” Rooney said. “We haven’t historically had enough info to do that, but this study provides a benchmark for scientists and policymakers.”

A need for further research

In this study, Rooney and his team managed the field trials and helped with phenotyping. Mullet and his team characterized the root system and the genes expressed within.

Over multiple years, the study considered in-depth how one bioenergy sorghum hybrid interacts with two soil types, Rooney said. He stresses the need to conduct further research.

“In this study, we didn’t sample the genetic diversity of bioenergy sorghum at all, except for one standard type,” Rooney said. “And looking at multiple environments and expanding the range of we are evaluating is essential.”

Bioenergy sorghum as part of a sustainable bioenergy production system

Modeling studies estimate that millions of acres of abandoned and marginal cropland in the U.S. are available for planting. Many of those acres are in the Gulf Coast region. The region is ideal for bioenergy sorghum production because of ample rainfall, long growing seasons and low competition with grain crops, Mullet said. Furthermore, the crop has improved over the years in terms of productivity, resilience and composition, thanks to Mullet’s and Rooney’s efforts.

“Recently, I’ve decided the most important thing we can do is continue research on bioenergy sorghum optimization, but also to help design and build biorefineries that will process materials from the crop in a way that’s optimal,” Mullet said.

Carbon captured in biofuels and bioproducts at biorefineries, and by bioenergy sorghum roots could generate carbon credits, potentially benefiting producers and industry.

Yet despite the Gulf Coast’s excellent potential for biofuels production, there are no bioenergy research centers and very few biorefineries in the region, Mullet said.

Therefore, Mullet is now working to attract industry and government funding to help build the next generation of biorefineries designed to use bioenergy sorghum biomass for the production of biofuels, bioproducts and biopower.

“The project has expanded to not just producing biofuels and bioproducts, but also directly capturing carbon and sequestering it,” he said.

Amanda Gaulke, assistant professor of economics in the College of Arts and Sciences, found that students who return to college and finish a bachelor’s degree earn on average $4,294 more immediately after graduation and experience an extra income growth of $1,121 per year, on average. The Economics of Education Review recently published the study.

“No matter how I looked at the data, those who returned and finished a bachelor’s degree see an economically meaningful increase in income after degree completion,” Gaulke said. “The average age at graduation for this sample is 27, so they certainly have a lot of working years left to experience improved labor market outcomes.”

While current economic literature mainly focuses on the traditional college student — those who graduate high school, go to college, earn a degree, and then start a career — Gaulke wanted to determine if returning to finish a bachelor’s degree resulted in improved economic outcomes compared to both those who never returned and those who returned to complete a bachelor’s degree but dropped out again.

“This information is important for people who are wondering if they should return to school,” Gaulke said. “When thinking in terms of weighing costs and benefits, it is important for those people to know that there are real economic benefits of going back and completing a bachelor’s degree.”

Gaulke’s study also shows students who re-enroll and earn a degree are significantly more likely to be employed, work more weeks and work more full-time weeks each quarter. Additionally, those students who return but do not complete a degree also realized slight income gains.

Ultimately, businesses and the U.S. economy also benefit from having a trained workforce.

“To maximize economic output, we have to use resources efficiently,” Gaulke said. “If employees are not as productive or skilled because they are unable to make well-informed decisions about re-enrolling and completing their bachelor’s degrees, this reduces worker productivity.”

Gaulke said another benefit of this study is that many institutions of higher education have concerns about enrollment numbers and are expanding their recruitment efforts beyond students coming straight from high school. Many private sector companies now offer services to help colleges and universities re-enroll students who left without completing their degrees. The results of this study suggest that colleges and universities that develop or implement policies to help students re-enroll and finish a bachelor’s degree can potentially improve enrollment numbers and also help improve economic outcomes for these students as well.

Individuals interested in returning to K-State to finish a degree can discover more information about the university’s admission process for returning students and apply online today.

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The sea off the west coast of South America is one of the most vital and productive fishing grounds on earth. Around eight percent of the global catch of marine species comes from the areas off the coasts of Peru, where the near-surface Humboldt Current provides a high nutrient supply and thus sufficient food for commercially exploited fish species such as the anchovy. Ten percent of the total global catch of anchovies alone comes from the region. Much of it is processed into fish meal and oil and used primarily for aquacultures in China and Norway. However, catches of anchovy in the Humboldt upwelling system are currently declining. The causes of species shifts are mainly due to climate change according to the results of the new study.

Researchers from the Institute of Geosciences at Kiel University, together with colleagues from GEOMAR Helmholtz Centre for Ocean Research and international partners, have for the first time investigated the relationships between temperature, oxygen, nutrient supply and the occurrence of individual fish species using paleo-oceanographic data from the Humboldt Current region. The scientists focused on the warm period about 125,000 years ago (Eemian interglacial). During this time, conditions were similar to those predicted by climate projections (e.g., the IPCC report) for the end of the 21st century at the latest: comparable primary production but water temperatures two degrees Celsius higher than today and increased oxygen deficiency in mid-depth water masses.

For their paleo-oceanographic studies, the researchers at Kiel University primarily analyzed small fish vertebrae that they were able to isolate from the sediment cores. According to the results, smaller, goby-like fish predominated in coastal waters during the ancient warm period, while anchovies made up only a small proportion. Fish with smaller body sizes can adapt better to warmer temperatures. They retain their high activity even in less oxygenated waters thanks to their larger gill surface area relative to their body volume.

“The conditions of this past warm period that we were able to reconstruct from our samples can definitely be compared to the current development and put in context with future scenarios,” says first author of the study, Dr. Renato Salvatteci, who is currently working at the Center for Ocean and Society of the Kiel Marine Science (KMS) priority research area at Kiel University and in the BMBF-funded Humboldt-Tipping project. “According to this, there is a clear regime shift towards smaller fish that feel more comfortable in the warm, lower-oxygen conditions. We conclude from our results that the effects of human-induced climate change may have a stronger influence on the evolution of stocks in the region than previously thought,” Salvatteci added. Smaller fish are harder to catch and less palatable. According to the report, the impact on the Peru region, local fisheries income and global trade in anchovies could be far-reaching — potentially affecting global food security.

“Our studies using sediment cores can give us fairly accurate information about the changes and their dynamics in highly productive coastal waters around the world that have occurred in the wake of different climate states and over different time scales,” explains Professor Ralph Schneider, a paleoclimate researcher at the Institute of Geosciences at Kiel University and co-author of the study.

The results indicate that due to increasing warming in the Humboldt Current upwelling area, the ecosystem is heading towards a tipping point beyond which anchovy will begin to retreat and not continue to dominate nearshore fishing grounds. “Despite a flexible, sustainable and adaptive management strategy, anchovy biomass and landings have declined, suggesting that we are closer to the ecological tipping point than suspected,” summarizes lead author Renato Salvatteci.

The results of the study help to better assess the extent to which a warming ocean can provide sufficient food for the world’s population and what changes should be expected for the development of important fish species such as the anchovy.

The study was funded by the Collaborative Research Center (SFB) 754 “Climate-Biogeochemical Interactions in the Tropical Ocean,” a collaborative project of Kiel University (CAU) and GEOMAR Helmholtz Centre for Ocean Research Kiel. Additional support came from the BMBF project Humboldt-Tipping, coordinated at the Center for Ocean and Society, as well as funding from the Emmy-Noether Junior Research Group ICONOX at GEOMAR. First author Renato Salvatteci was further supported by a fellowship from the Alexander von Humboldt Foundation.

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“Red dwarfs” are small stars and thus much cooler than our Sun. Around stars like these, liquid water is possible on planets much closer to the star than in our solar system. The distance between an exoplanet and its star is a crucial factor in its detection: the closer a planet is to its host star, the higher the probability that it can be detected.

In a study recently published in the journal Astronomy & Astrophysics, researchers led by Dr. Nicole Schanche of the Center for Space and Habitability CSH of the University of Bern report the discovery of the exoplanet TOI-2257 b orbiting a nearby red dwarf. Nicole Schanche is also a member of the National Center of Competence in Research PlanetS, which the University of Bern runs together with the University of Geneva.

A special telescope is part of the solution

Exoplanets that are very far from our solar system cannot be observed directly with a telescope — they are too small and reflect too little light. However, one way to detect such planets is the transit method. This involves using telescopes to look for dips in the star’s brightness that occur when planets pass in front of the star. Repeated observations of the dips in the star’s brightness give precise measurements of the planet’s orbital period around the star, and the depth of the transit allows researchers to determine the planet’s diameter. When combined with planet mass estimates from other methods, such as using radial velocity measurements, the planet density can be calculated.

Planet TOI-2257 b was initially identified by data from NASA’s Transiting Exoplanet Survey Satellite TESS space telescope. The small star was observed for a total of four months, but the gaps between observations meant that it was not clear whether the decrease in brightness could be explained by the transit of a planet with an orbit of 176, 88, 59, 44 or 35 days.

Observation of the star with the Las Cumbres Observatory Global Telescope subsequently ruled out the possibility that a planet with a 59-day orbital period was causing the drop in brightness. “Next, we wanted to find out if the 35-day orbital period could be possible,” explains Nicole Schanche.

The Mexico-based SAINT-EX telescope, co-operated by the CSH and the NCCR PlanetS, is purpose-built to study red dwarfs and their planets in more detail. SAINT-EX is an acronym that stands for Search And characterIsatioN of Transiting EXoplanets. The project was named in honor of Antoine de Saint-Exupéry (Saint-Ex), the famous writer, poet and aviator. SAINT-EX observed a partial transit of TOI-2257 b and was able to confirm the exoplanet’s exact orbital period around its star, 35 days. “Another 35 days later, SAINT-EX was able to observe the entire transit, which gave us even more information about the properties of the system,” says co-author Robert Wells from the CSH, who was involved in the data processing.

A temperate planet with an irregular orbit

With its 35-day orbital period, TOI-2257 b orbits the host star at a distance where liquid water is possible on the planet, and therefore conditions favorable for the emergence of life could exist. Planets in this so-called “habitable zone” near a small red dwarf star are easier to study because they have shorter orbital periods and can therefore be observed more often. The radius of TOI-2257 b (2.2 times larger than Earth’s) suggests that the planet is rather gaseous, with high atmospheric pressure not conducive to life.

“We found that TOI-2257 b does not have a circular, concentric orbit,” explains Nicole Schanche. In fact, it is the most eccentric planet orbiting a cool star ever discovered. “In terms of potential habitability, this is bad news,” Nicole Schanche continues. “While the planet’s average temperature is comfortable, it varies from -80°C to about 100°C depending on where in its orbit the planet is, far from or close to the star.” A possible explanation for this surprising orbit is that further out in the system a giant planet is lurking and disturbing the orbit of TOI 2257 b. Further observations measuring the radial velocity of the star will help confirm the eccentricity and search for possible additional planets that could not be observed in transit.

Candidate for observation with JWST

The James Webb Space Telescope (JWST), which successfully launched on December 25, will revolutionize research into exoplanet atmospheres. In order to prioritize good candidates for observations with the JWST, a transmission spectroscopy metric (TSM) was developed that rates different system properties. TOI-2257 b is well positioned with respect to TSM and is one of the most attractive sub-Neptune targets for further observations. “In particular, the planet could be studied for signs of features such as water vapor in the atmosphere,” Nicole Schanche concludes.

In a study published this month in The International Journal of High Performance Computing Applications, a research team led by the University of Tsukuba describes a highly efficient method for simulating light-matter interactions at the atomic scale.

What makes these interactions so difficult to simulate? One reason is that phenomena associated with the interactions encompass many areas of physics, involving both the propagation of light waves and the dynamics of electrons and ions in matter. Another reason is that such phenomena can cover a wide range of length and time scales.

Given the multiphysics and multiscale nature of the problem, light-matter interactions are typically modeled using two separate computational methods. The first is electromagnetic analysis, whereby the electromagnetic fields of the light are studied; the second is a quantum-mechanical calculation of the optical properties of the matter. But these methods assume that the electromagnetic fields are weak and that there is a difference in the length scale.

“Our approach provides a unified and improved way to simulate light-matter interactions,” says senior author of the study Professor Kazuhiro Yabana. “We achieve this feat by simultaneously solving three key physics equations: the Maxwell equation for the electromagnetic fields, the time-dependent Kohn-Sham equation for the electrons, and the Newton equation for the ions.”

The researchers implemented the method in their in-house software SALMON (Scalable Ab initio Light-Matter simulator for Optics and Nanoscience), and they thoroughly optimized the simulation computer code to maximize its performance. They then tested the code by modeling light-matter interactions in a thin film of amorphous silicon dioxide, composed of more than 10,000 atoms. This simulation was carried out using almost 28,000 nodes of the fastest supercomputer in the world, Fugaku, at the RIKEN Center for Computational Science in Kobe, Japan.

“We found that our code is extremely efficient, achieving the goal of one second per time step of the calculation that is needed for practical applications,” says Professor Yabana. “The performance is close to its maximum possible value, set by the bandwidth of the computer memory, and the code has the desirable property of excellent weak scalability.”

Although the team simulated light-matter interactions in a thin film in this work, their approach could be used to explore many phenomena in nanoscale optics and photonics.

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