The findings could eventually help farmers better detect, monitor and control fall armyworm populations, which negatively affect some 350 plant species — including crops like corn and cotton as well as turfgrass and other cultivated grasses.

“Nonanal is emitted by people, birds and even apples,” said Coby Schal, Blanton J. Whitmire Distinguished Professor of Entomology and co-corresponding author of a paper describing the research. “It is a universal attractant that, by itself, doesn’t have much of an effect. But when a certain percentage of nonanal is added to the multi-chemical attractant mixture discovered nearly 40 years ago, it has a highly stimulatory effect — in this case attracting male fall armyworm moths in the lab and then attracting male moths to traps in field experiments.”

Fall armyworms are found mostly in warmer climates; after originating in South America they spread to North America and then to sub-Saharan Africa, the Middle East, the Indian subcontinent, China, and, most recently, Australia. Arguably one of the world’s most devastating pests, fall armyworm caterpillars can rapidly chew through crops and lawns.

The researchers started examining ways to attract and then trap male moths as part of a “mating disruption” strategy.

“When you see fall armyworm moths you know that — two weeks later — you’re going to have caterpillars,” Schal said. “So controlling the early flying adults is key. Mating disruption is the way to go when using pheromones, as males will find traps rather than females. Pests have been eliminated from wide areas using several approaches including mating disruption — like pink bollworm, a major cotton pest in the Southwest.” Other uses of the pheromone include detection of the fall armyworm in areas not yet invaded by this pest and lure-and-kill, where the pheromone attracts the fall armyworm to an insecticide or a pathogen.

The researchers used gas chromatography, in which chemical compounds are separated in a controllable oven, to test whether the fall armyworm males would respond to other chemicals besides the known blend of chemicals. By connecting this instrument to the antennae of fall armyworm males and monitoring their electrical activity, the researchers saw that nonanal stimulated male fall armyworms.

The researchers then tested the blend with nonanal in other lab tests. Males were somewhat attracted to the traditional pheromone blend, but adding the “right amount” of nonanal to the blend greatly increased the response. The right amount turned out to be about 1% percent of the total blend, as adding too little nonanal increased the response over the traditional blend, but not by much.

Finally, the researchers used bait-and-trap experiments on NC State cotton and sorghum research fields in Raleigh and Clayton, where they tried to use different pheromone blends to capture male moths. There, they showed that nonanal by itself had no effect on males. Higher doses of nonanal in the traditional blend — at 2% and 4% concentrations — reduced the compound’s effectiveness. Again, 1% nonanal in the blend emerged as the most effective, capturing more males.

Interestingly, the shape of the trapping device also affected the success rates in capturing males. Cone-shaped traps did not perform as well as bucket-shaped traps.

The field studies also showed few other insect species — or female fall armyworms — trapped.

“We have tweaked this system to make it highly species-specific, which is especially important in places where similar moth species live,” Schal said.

The researchers filed a patent on the discovery and have exclusive licensing agreements with industry partners that will further test nonanal’s effectiveness when added to the traditional pheromone blend.

The study appears in Pest Management Science. Ahmed M. Saveer, Eduardo Hatano and Ayako Wada-Katsumata from NC State co-authored the paper, as did Robert L. Meagher from the USDA’s Agricultural Research Service. Funding was provided by a N.C. Biotechnology Center Flash Grant (2020-FLG-3809), by the USDA Southern IPM Center (2021-1645), by the U.S. National Science Foundation (NSF IOS1456973) and by the Blanton J. Whitmire Endowment at NC State.

Earth Day 2023, which takes place on April 22, marks the 53rd year that people have come out into the streets to rally for planetary responsibility, joined park and environmental cleanups, and participated in climate learning events. The first Earth Day was the largest public demonstration in history as of that time. Michael Karapetian, the Great Global Cleanup Campaign coordinator for Earth Day Network explains how to participate in this year’s Great Global Cleanup events, which will be focused on improving the management of waste, particularly food waste. See the map of Earth Day events to find cleanups near you.

Cleanup events give everyone — individuals and organizations — the “opportunity to see the positive, tangible impacts their actions have on our environment and in the fight to create a waste-free world.” Getting out to clean up a park or a beach, where finding plastic litter is a powerful reminder about the choices we make when buying and disposing of items made with plastic, which range from fast-fashion polyester clothing to bottles and cigarette butts. Michael also provides updates about Earth Day Network’s End Plastic Pollution movement and discusses recent reforestation projects in India, where The Canopy Project is planting mangrove trees in coastal areas. You can find local cleanups and learn how to participate in Earth Day events all year long at  earthday.org.

The study, led by the University of California, Davis, is published in the journal Ecology and Evolution and was conducted in alpine regions stretching nearly 200 miles from Alpine County just south of Lake Tahoe, along the spine of the Sierra and south to Tulare and Inyo counties.

The study characterizes the niche space of three species of squirrel: the yellow-bellied marmot, Belding’s ground squirrel and the golden-mantled ground squirrel. The authors analyzed nearly 6,000 observations of individual squirrels, collected from field survey data conducted over four years.

For this study, the “niche” describes all the conditions in the environment that are important for an animal to live in an area. Understanding the niche of animals helps scientists learn which changes are expected to most impact a species and, therefore, which animals may be most vulnerable to climate change.

“We’re trying from a conservation perspective to understand what will happen to these species as the world changes,” said lead author Aviva Rossi, who conducted the study while a UC Davis graduate student in the Department of Wildlife, Fish and Conservation Biology. “A quantitative analysis of what makes a species able to live where it lives allows us to bring that information forward, and better understand differences between species.”

What doesn’t change

Niche was defined not only by climate, but also by topography (like how steep an area was) and land cover (such as meadows or forests). Some of these nonclimate environmental conditions, like slope or the presence of rocks, rarely change.

Although all three squirrel species occur in the same region, they each use that space a little differently because their niche is different.

Grassland meadows were particularly important for yellow-bellied marmots and the Belding’s ground squirrel. Yet, within a meadow, marmots preferred drier conditions, while Belding’s ground squirrels favored wet vegetation.

Golden-mantled squirrels — a common sight at area campgrounds — preferred forested areas and do well with more snow-free days. Belding’s ground squirrels preferred having snow on the ground longer.

Even with these overall selection patterns, there can still be too much of a good thing in extreme years, Rossi said.

Mammals in high-elevation mountains are often perceived as vulnerable to climate shifts, the study notes. Yet, the results underscore the importance of including factors that go beyond climate when defining their niche.

Making better decisions

Rossi notes that climate change is often viewed through a lens of hope or despair, but the study illustrated how its impacts are more complex.

“There’s hope in some areas and not in others,” Rossi said. “If one species is there because of a meadow and another is there because of an outcropping of rocks, as the world changes, it may change where one species lives but not the other. We just want to better understand what’s likely to happen so we can make better conservation decisions.”

The study’s co-authors include Robert Klinger of the U.S. Geological Survey, and Elise Hellwig and Dirk Van Vuren of the UC Davis Department of Wildlife Fish and Conservation Biology.

The study was funded through the USGS National Climate Change and Wildlife Science Center, Yosemite National Park, Sequoia and Kings Canyon National Parks, with support from the Gulch Environmental Foundation.

Dr. Emanuela Gionfriddo, an assistant professor of analytical chemistry, and Nipunika H. Godage, a Ph.D. candidate in UToledo’s Dr. Nina McClelland Laboratory for Water Chemistry and Environmental Analysis, published research in the journal Analytical and Bioanalytical Chemistry outlining their groundbreaking method that is able to detect 79 pesticide residues in human blood plasma at “ultra-trace” levels, or parts per trillion.

“This has the potential to be applied to human exposure studies for the general public such as exposure through food or contaminated water but, most importantly, agricultural workers who have a higher potential for acute exposure to these toxic chemicals, which typically occurs through the skin, with pesticides then passing into the bloodstream and circulating through the body,” Gionfriddo said.

Pesticides are widely used in farming to prevent or reduce produce losses caused by pests and improve the quality of fruits and vegetables, but human exposure during mixing or application has been reported to cause neurological disorders, poisoning, cancer, reproductive disruptions, respiratory problems and chronic kidney diseases among farm workers.

Though pesticides are regulated by the U.S. Environmental Protection Agency, Gionfriddo said the legalization of cannabis recently in several states has led to “inexperienced” farmers exposing themselves to the harmful chemicals since those workers are less familiar with pesticide safety equipment and procedures as well as proper pesticide storage and handling.

The pesticides selected for her study are the most commonly used pesticides during cannabis cultivation.

Gionfriddo’s new testing method uses what’s called bio solid-phase microextraction with liquid chromatography-tandem mass spectrometry.

“To meet the growing demands of regulatory agencies and routine analysis laboratories, sample throughput and method tunability is critical,” Gionfriddo said. “Using automated samplers, the preparation time per sample is 1.7 minutes.”

And as occupational exposure to pesticides can occur at varying concentration levels, it is important for any method to quantify pesticides at low concentrations. The new testing method demonstrated higher sensitivity, precision and accuracy and a drastic reduction in abnormalities compared to the commonly used approach, known as QuEChERS, which stands for Quick, Easy, Cheap, Effective, Rugged and Safe but can be labor intensive with prolonged workflows.

Last week during National Farmworker Awareness Week, the U.S. EPA said pesticide exposure doesn’t only happen when working in the fields. The federal agency said pesticide take-home exposure can occur when farm workers go home bearing pesticide residues that may cling to their skin, clothing, hats, boots, tools, lunch coolers or other items in their work environment. Their children may then be exposed to these pesticide residues.

“Assessing pesticide exposure quickly and thoroughly is crucial for the health and safety of workers and their families, to correct malpractices in pesticide storage and application, and to prevent further exposure,” Godage said. “Our new method can extract and analyze simultaneously a wide variety of pesticides from human plasma.”

To learn more about the U.S. EPA’s Occupational Pesticide Safety and Health program, visit the agency’s website (https://www.epa.gov/pesticide-worker-safety).

However, not all possible MOF structures are stable enough to be deployed for applications such as catalyzing reactions or storing gases. To help researchers figure out which MOF structures might work best for a given application, MIT researchers have developed a computational approach that allows them to predict which structures will be the most stable.

Using their computational model, the researchers have identified about 10,000 possible MOF structures that they classify as “ultrastable,” making them good candidates for applications such as converting methane gas to methanol.

“When people come up with hypothetical MOF materials, they don’t necessarily know beforehand how stable that material is,” says Heather Kulik, an MIT associate professor of chemistry and chemical engineering, and the senior author of the study. “We used data and our machine-learning models to come up with building blocks that were expected to have high stability, and when we recombined those in ways that were considerably more diverse, our dataset was enriched with materials with higher stability than any previous set of hypothetical materials people had come up with.”

MIT graduate student Aditya Nandy is the lead author of the paper, which appears today in the journal Matter. Other authors are MIT postdoc Shuwen Yue, graduate students Changhwan Oh and Gianmarco Terrones, Chenru Duan PhD ’22, and Yongchul G. Chung, an associate professor of chemical and biomolecular engineering at Pusan National University.

Modeling MOFs

Scientists are interested in MOFs because they have a porous structure that makes them well-suited to applications involving gases, such as gas storage, separating similar gases from each other, or converting one gas to another. Recently, scientists have also begun to explore using them to deliver drugs or imaging agents within the body.

The two main components of MOFs are secondary building units — organic molecules that incorporate metal atoms such as zinc or copper — and organic molecules called linkers, which connect the secondary building units. These parts can be combined together in many different ways, just like LEGO building blocks, Kulik says.

“Because there are so many different types of LEGO blocks and ways you can assemble them, it gives rise to a combinatorial explosion of different possible metal organic framework materials,” she says. “You can really control the overall structure of the metal organic framework by picking and choosing how you assemble different components.”

Currently, the most common way to design MOFs is through trial-and-error. More recently, researchers have begun to try computational approaches to designing these materials. Most such studies have been based on predictions of how well the material will work for a particular application, but they don’t always take into account the stability of the resulting material.

“A really good MOF material for catalysis or for gas storage would have a very open structure, but once you have this open structure, it may be really hard to make sure that that material is also stable under long-term use,” Kulik says.

In a 2021 study, Kulik reported a new model that she created by mining a few thousand papers on MOFs to find data on the temperature at which a given MOF would break down and whether particular MOFs can withstand the conditions needed to remove solvents used to synthesize them. She trained the computer model to predict those two features — known as thermal stability and activation stability — based on the molecules’ structure.

In the new study, Kulik and her students used that model to identify about 500 MOFs with very high stability. Then, they broke those MOFs down into their most common building blocks — 120 secondary building units and 16 linkers.

By recombining these building blocks using about 750 different types of architectures, including many that are not usually included in such models, the researchers generated about 50,000 new MOF structures.

“One of the things that was unique about our set was that we looked at a lot more diverse crystal symmetries than had ever been looked at before, but [we did so] using these building blocks that had only come from experimentally synthesized highly stable MOFs,” Kulik says.

Ultrastability

The researchers then used their computational models to predict how stable each of these 50,000 structures would be, and identified about 10,000 that they deemed ultrastable, both for thermal stability and activation stability.

They also screened the structures for their “deliverable capacity” — a measure of a material’s ability to store and release gases. For this analysis, the researchers used methane gas, because capturing methane could be useful for removing it from the atmosphere or converting it to methanol. They found that the 10,000 ultrastable materials they identified had good deliverable capacities for methane and they were also mechanically stable, as measured by their predicted elastic modulus.

“Designing a MOF requires consideration of many types of stability, but our models enable a near-zero-cost prediction of thermal and activation stability,” Nandy says. “By also understanding the mechanical stability of these materials, we provide a new way to identify promising materials.”

The researchers also identified certain building blocks that tend to produce more stable materials. One of the secondary building units with the best stability was a molecule that contains gadolinium, a rare-earth metal. Another was a cobalt-containing porphyrin — a large organic molecule made of four interconnected rings.

Students in Kulik’s lab are now working on synthesizing some of these MOF structures and testing them in the lab for their stability and potential catalytic ability and gas separation ability. The researchers have also made their database of ultrastable materials available for researchers interested in testing them for their own scientific applications.

The research was funded by the U.S. Defense Advanced Research Projects Agency, a National Science Foundation Graduate Research Fellowship, the Office of Naval Research, the Department of Energy, an MIT Portugal Seed Fund, and the National Research Foundation of Korea.

The seas surrounding the Arctic are important fisheries and ecological regions; they are also among the areas most affected by climate change. The effects of warming waters and loss of sea ice on the biodiversity of these waters, and hence their ecology, is still not fully understood.

An international team of researchers led by Dr. Irene D. Alabia at the Arctic Research Center at Hokkaido University has examined Arctic-wide and regional changes in species richness, composition, and potential species associations. Their findings, published in the journal Scientific Reports, show that recent changes in biodiversity were driven by pervasive poleward species range expansions.

“We used data on the occurrences of 69 species of apex predators and mesopredators in eight Arctic areas from 2000-2019,” Alabia explains. “We combined this information with climate and productivity data across the same period to map species-specific habitat distributions.”

The team calculated the species richness, community composition, and co-occurrences between species pairs throughout the twenty-year study period at each of the eight Arctic areas. They were able to infer potential species associations and changes therein from the co-occurrence data.

Their most important finding was that species richness — the number of different species represented in the study regions — has increased over the study period, driven by the northward migration of apex predators such as whales, sharks and seabirds. Mesopredators such as fish and crabs exhibited a relatively limited degree of northward migration, confined to the shallow continental shelf seas of the Pacific and Atlantic. Although the spatial extent varies, this northward expansion was driven by changes in either climate, productivity, or both.

These climate-driven biodiversity changes, in turn, led to alterations in potential species associations due to habitat overlap between taxa from different marine communities during unprecedented periods of temperature and sea ice changes.

“Our findings revealed that changes in climate and species richness in the Arctic vary across different large marine areas and highlight potential regions of climate and productivity hotspots, and emerging areas of species gain,” Alabia concluded. “This information is relevant for strengthening conservation and management efforts for the sustainable use of resources under the expanding footprints of climate change in the Arctic.”

The approach uses an innovative copper-containing polymeric filter and essentially converts CO₂ into sodium bicarbonate (aka baking soda) that can be released harmlessly into the ocean. This new hybrid material, or filter, is called DeCarbonHIX (i.e., decarbonization through hybrid ion exchange material), and is described in a paper recently published in the journal Science Advances.

The research, which demonstrated a 300 percent increase in the amount of carbon captured compared with existing direct air capture methods, has garnered international attention from media outlets like the BBC, CNN, Fast Company, and The Daily Beast, and professional organizations like the American Chemical Society. SenGupta himself has been fielding interest in the technology from companies based in Brazil, Ireland, and the Middle East.

“The climate crisis is an international problem,” says SenGupta, who is a professor of chemical and biomolecular engineering and civil and environmental engineering in Lehigh’s P.C. Rossin College of Engineering and Applied Science. “And I believe we have a responsibility to build direct air capture technology in a way that it can be implemented by people and countries around the world. Anyone who can operate a cell phone should be able to operate this process. This is not technology for making money. It’s for saving the world.”

The work is yet another extension of SenGupta’s personal and professional commitment to developing technologies that benefit humanity, and in particular, marginalized communities around the world. His research on water science and technology has included drinking water treatment methodologies, desalination, municipal wastewater reuse, and resource recovery. He invented the first reusable, arsenic-selective hybrid anion exchanger nanomaterial (HAIX-Nano), and as a result, more than two million people around the world now drink arsenic-safe water. Two of his patents have been recognized as “Patents for Humanity” by the US patent and Trademark Office.

His invention of DeCarbonHIX was the outcome of an ongoing CO₂-driven wastewater desalination project funded by the Bureau of Reclamation under the jurisdiction of the U.S. Department of the Interior. SenGupta and his students were on the lookout for a reliable supply of CO₂ even in remote places. That quest led the way to the field of direct air capture, or DAC, and the creation of DeCarbonHIX. This subject was the dissertation topic for environmental engineering student Hao Chen ’23 PhD, who successfully defended his PhD in March and will receive his doctorate in May.

Capturing carbon at lower concentrations

The most abundant of the greenhouse gasses contributing to global warming is carbon dioxide. In 2021, global emissions of CO₂ rose by 6 percent from the previous year — to 36.3 gigatons, according to the International Energy Agency. Just one gigaton (equal to 1 billion tons) is the equivalent of the mass of all land mammals on earth.

Emissions from greenhouse gasses have increased global temperatures by approximately 1.1 degrees Celsius above pre-industrial levels, according to the Intergovernmental Panel on Climate Change. In its 2021 working group report, the IPCC estimates the average yearly temperature over the next 20 years is expected to rise by at least 1.5 degrees Celsius. The warmer the earth gets, the greater the fallout in terms of rising sea levels, extreme storm events, and ecological disruption, all of which have repercussions on global health, security, and stability.

“The worst part of this crisis is that people who are marginalized, who are poor, will suffer 10 times more than those who contributed to this situation,” says SenGupta.

There are three ways to reduce CO₂, he says. The first — government action — can reduce emissions, but that won’t address what’s already in the air.

“The second way is removing it from point sources, places like chimneys and stacks where carbon dioxide is being emitted in huge amounts,” he says. “The good thing about that is you can remove it at very high concentrations, but it only targets emissions from specific sources.”

The newest method is called direct air capture, which, he says, “allows you to remove CO₂ from anywhere, even your own backyard.”

With DAC, chemical processes remove CO₂ from the atmosphere, after which it’s typically stored underground. However, says SenGupta, the technology is limited by its capacity. It can’t capture enough CO2 to overcome the energy cost of running the process.

“If you’re capturing carbon dioxide from a chimney at a plant, the amount of CO₂ in the air can be upwards of 100,000 parts per million,” he says. “At that concentration, it’s easy to remove. But generally speaking, the CO2 level in the air is around 400 parts per million. That’s very high from a climate change point of view, but for removal purposes, we consider that ultra-dilute. Current filter materials just can’t collect enough of it.”

Another challenge with DAC involves storage. After the CO₂ is captured, it’s dissolved, put under pressure, liquified, and typically stored miles underground. A DAC operation must then be located in an area with enough geological storage — and stability. A country like Japan, for instance, can’t pump CO₂ underground because the area is prone to earthquakes.

Seeing a solution in seawater

SenGupta has developed a DAC method that overcomes both the capture problem and the issue of storage.

For the capture problem, he developed DeCarbonHIX — a mechanically strong, chemically stable sorbent (a material used to absorb liquids or gasses) — that contains copper.

“The copper changes an intrinsic property of the parent polymer material and enhances the capturing capacity by 300 percent,” he says. “We showed that for direct air capture from air with 400 parts per million of CO₂, we achieve capacity, meaning capacity is no longer a function of how much carbon dioxide is in the air. The filter will get saturated completely at any concentration, which means you can perform DAC in your backyard, in the middle of the desert, or in the middle of the ocean.”

The ocean is actually SenGupta’s solution to the storage problem. His DAC process starts with air blowing through the filter to capture CO₂. Once the filter is saturated with gas molecules (determined by measuring the amount of gas going into the filter versus coming out of it), seawater is passed through the filter. The seawater converts the carbon dioxide to sodium bicarbonate (you likely know it as baking soda, but lose the visual as we’re talking about a dissolved solution here). The dissolved sodium bicarbonate is then released directly into the ocean, what Sengupta calls “an infinite sink.”

“And it has no adverse impact on the ocean whatsoever,” says SenGupta. “It doesn’t change the salinity at all.”

In fact, he says, the sodium bicarbonate, which is slightly alkaline, may improve the health of the ocean. That’s because elevated levels of CO₂ in the atmosphere have gradually reduced the pH of the ocean, causing acidification. More acidic waters harm the growth and reproduction of marine life like corals and plankton and can create catastrophic collapses in the food chain.

“Sodium bicarbonate may reverse that lowering of pH,” he says.

It’s worth noting, he says, that like existing DAC processes, DeCarbonHIX can also be desorbed with hot water or steam, and pure CO₂ can be recovered, compressed, and stored underground in geological storage.

“In reality, this new filter material offers a dual mode of desorption and sequestration.”