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      Flower shape and size impact bees’ chances of catching gut parasites

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      Bees that land on short, wide flowers can fly away with an upset stomach.  

      Common eastern bumblebees (Bombus impatiens) are more likely to catch a diarrhea-inducing gut parasite from purple coneflowers, black-eyed Susans and other similarly shaped flora than other flowers, researchers report in the July Ecology. Because parasites and diseases contribute to bee decline, the finding could help researchers create seed mixes that are more bee-friendly and inform gardeners’ and land managers’ decisions about which flower types to plant.

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      The parasite (Crithidia bombi) is transmitted when the insects accidentally ingest contaminated bee feces, which “tends to make the bees dopey and lethargic,” says Rebecca Irwin, a community and evolutionary ecologist at North Carolina State University in Raleigh. “It isn’t the number one bee killer out there,” but bees sickened with it can struggle with foraging.    

      In laboratory experiments involving caged bees and 16 plant species, Irwin and her colleagues studied how different floral attributes affected transmission of the gut parasite. They focused on three factors of transmission: the amount of poop landing on flowers when bees fly and forage, how long the parasite survives on the plants and how easily the parasite is transmitted to new bees. Multiplied together, these three factors show the overall transmission rate.

      Compared with plants with long, narrow flowers like phlox and bluebeards, short, wide flowers had more feces land on them and transmitted the parasite more easily to the pollinators, increasing the overall parasite transmission rate for these flowers. However, parasite survival times were reduced on these blooms. This is probably due to the open floral shapes increased exposure to ultraviolet light, speeding the drying out of parasite-laden “fecal droplets,” Irwin says.

      The findings confirm a new theory suggesting that traits, such as flower shape, are better predictors of disease transmission than individual species of plants, says Scott McArt, an entomologist focusing on pollinator health at Cornell University who wasn’t involved with the study. Therefore, “you don’t need to know everything about every plant species when designing your pollinator-friendly garden or habitat restoration project.”

      Instead, to limit disease transmission among bees, it’s best to choose plants that have narrower, longer flowers, he says. “Wider and shorter flowers are analogous to the small, poorly ventilated rooms where COVID is efficiently transmitted among humans.”  

      If ripping out coneflowers or black-eyed Susans isn’t palatable, don’t fret. Irwin recommends continuing to plant a diversity of flower types. This helps if one type of flower is “a high transmitting species,” she notes. In the future, she plans to conduct field experiments examining other factors that could influence parasite transmission, such as whether bees are driven to visit certain types of flowers more often in nature.   More

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      How to build better ice towers for drinking water and irrigation

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      There’s a better way to build a glacier.

      During winter in India’s mountainous Ladakh region, some farmers use pipes and sprinklers to construct building-sized cones of ice. These towering, humanmade glaciers, called ice stupas, slowly release water as they melt during the dry spring months for communities to drink or irrigate crops. But the pipes often freeze when conditions get too cold, stifling construction.

      Now, preliminary results show that an automated system can erect an ice stupa while avoiding frozen pipes, using local weather data to control when and how much water is spouted. What’s more, the new system uses roughly a tenth the amount of water that the conventional method uses, researchers reported June 23 at the Frontiers in Hydrology meeting in San Juan, Puerto Rico.

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      “This is one of the technological steps forward that we need to get this innovative idea to the point where it’s realistic as a solution,” says glaciologist Duncan Quincey of the University of Leeds in England who was not involved in the research. Automation could help communities build larger, longer-lasting ice stupas that provide more water during dry periods, he says.

      Ice stupas emerged in 2014 as a means for communities to cope with shrinking alpine glaciers due to human-caused climate change (SN: 5/29/19). Typically, high-mountain communities in India, Kyrgyzstan and Chile pipe glacial meltwater into gravity-driven fountains that sprinkle continuously in the winter. Cold air freezes the drizzle, creating frozen cones that can store millions of liters of water.

      The process is simple, though inefficient. More than 70 percent of the spouted water may flow away instead of freezing, says glaciologist Suryanarayanan Balasubramanian of the University of Fribourg in Switzerland.

      So Balasubramanian and his team outfitted an ice stupa’s fountain with a computer that automatically adjusted the spout’s flow rate based on local temperatures, humidity and wind speed. Then the scientists tested the system by building two ice stupas in Guttannen, Switzerland — one using a continuously spraying fountain and one using the automated system.

      After four months, the team found that the continuously sprinkling fountain had spouted about 1,100 cubic meters of water and amassed 53 cubic meters of ice, with pipes freezing once. The automated system sprayed only around 150 cubic meters of water but formed 61 cubic meters of ice, without any frozen pipes.

      The researchers are now trying to simplify their prototype to make it more affordable for high-mountain communities around the world. “We eventually want to reduce the cost so that it is within two months of salary of the farmers in Ladakh,” Balasubramanian says. “Around $200 to $400.” More

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      Megatooth sharks may have been higher on the food chain than any ocean animal ever

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      Whenever paleontologist Dana Ehret gives talks about the 15-meter-long prehistoric sharks known as megalodons, he likes to make a joke: “What did megalodon eat?” asks Ehret, Assistant Curator of Natural History at the New Jersey State Museum in Trenton. “Well,” he says, “whatever it wanted.”

      Now, there might be evidence that’s literally true. Some megalodons (Otodus megalodon) may have been “hyper apex predators,” higher up the food chain than any ocean animal ever known, researchers report in the June 22 Science Advances. Using chemical measurements of fossilized teeth, scientists compared the diets of marine animals — from polar bears to ancient great white sharks — and found that megalodons and their direct ancestors were often predators on a level never seen before.

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      The finding contradicts another recent study, which found megalodons were at a similar level in the food chain as great white sharks (SN: 5/31/22). If true, the new results might change how researchers think about what drove megalodons to extinction around 3.5 million years ago.

      In the latest study, researchers examined dozens of fossilized teeth for varieties of nitrogen, called isotopes, that have different numbers of neutrons. In animals, one specific nitrogen isotope tends to be more common than another. A predator absorbs both when it eats prey, so the imbalance between the isotopes grows further up the food chain. 

      For years, scientists have used this trend to learn about modern creatures’ diets. But researchers were almost never able to apply it to fossils millions of years old because the nitrogen levels were too low. In the new study, scientists get around this by feeding their samples to bacteria that digest the nitrogen into a chemical the team can more easily measure.

      The result: Megalodon and its direct ancestors, known collectively as megatooth sharks, showed nitrogen isotope excesses sometimes greater than any known marine animal. They were on average probably two levels higher on the food chain than today’s great white sharks, which is like saying that some megalodons would have eaten a beast that ate great whites.

      “I definitely thought that I’d just messed up in the lab,” says Emma Kast, a biogeochemist at the University of Cambridge. Yet on closer inspection, the data held up.

      The result is “eyebrow-raising,” says Robert Boessenecker, a paleontologist at the College of Charleston in South Carolina who was not involved in the study. “Even if megalodon was eating nothing but killer whales, it would still need to be getting some of this excess nitrogen from something else,” he says, “and there’s just nothing else in the ocean today that has nitrogen isotopes that are that concentrated.”

      “I don’t know how to explain it,” he says.

      There are possibilities. Megalodons may have eaten predatory sperm whales, though those went extinct before the megatooth sharks. Or megalodons could have been cannibals (SN: 10/5/20).  

      Another complication comes from the earlier, contradictory study. Those researchers examined the same food chain —  in some cases, even the same shark teeth — using a zinc isotope instead of nitrogen. They drew the opposite conclusion, finding megalodons were on a similar level as other apex predators.

      The zinc method is not as established as the nitrogen method, though nitrogen isotopes have also rarely been used this way before. “It could be that we don’t have a total understanding and grasp of this technique,” says Sora Kim, a paleoecologist at the University of California, Merced who was involved in both studies. “But if [the newer study] is right, that’s crazy.”

      Confirming the results would be a step toward understanding why megalodons died off. If great whites had a similar diet, it could mean that they outcompeted megalodons for food, says Ehret, who was not involved in the study. The new findings suggest that’s unlikely, but leave room for the possibility that great whites competed with — or simply ate — juvenile megalodons (SN: 1/12/21). 

      Measuring more shark teeth with both techniques could solve the mystery and reconcile the studies. At the same time, Kast says, there’s plenty to explore with their method for measuring nitrogen isotopes in fossils. “There’s so many animals and so many different ecosystems and time periods,” she says. 

      Boessenecker agrees. When it comes to the ancient oceans, he says, “I guarantee we’re going to find out some really weird stuff.” More

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      Earth’s oldest known wildfires raged 430 million years ago

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      Bits of charcoal entombed in ancient rocks unearthed in Wales and Poland push back the earliest evidence for wildfires to around 430 million years ago. Besides breaking the previous record by about 10 million years, the finds help pin down how much oxygen was in Earth’s atmosphere at the time.

      The ancient atmosphere must have contained at least 16 percent oxygen, researchers report June 13 in Geology. That conclusion is based on modern-day lab tests that show how much oxygen it takes for a wildfire to take hold and spread.

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      While oxygen makes up 21 percent of our air today, over the last 600 million years or so, oxygen levels in Earth’s atmosphere have fluctuated between 13 percent and 30 percent (SN: 12/13/05). Long-term models simulating past oxygen concentrations are based on processes such as the burial of coal swamps, mountain building, erosion and the chemical changes associated with them. But those models, some of which predict lower oxygen levels as low as 10 percent for this time period, provide broad-brush strokes of trends and may not capture brief spikes and dips, say Ian Glasspool and Robert Gastaldo, both paleobotanists at Colby College in Waterville, Maine.

      Charcoal, a remnant of wildfire, is physical evidence that provides, at the least, a minimum threshold for oxygen concentrations. That’s because oxygen is one of three ingredients needed to create a wildfire. The second, ignition, came from lightning in the ancient world, says Glasspool. The third, fuel, came from burgeoning plants and fungus 430 million years ago, during the Silurian Period. The predominant greenery were low-growing plants just a couple of centimeters tall. Scattered among this diminutive ground cover were occasional knee-high to waist-high plants and Prototaxites fungi that towered up to nine meters tall. Before this time, most plants were single-celled and lived in the seas.

      Once plants left the ocean and began to thrive, wildfire followed. “Almost as soon as we have evidence of plants on land, we have evidence of wildfire,” says Glasspool.

      That evidence includes tiny chunks of partially charred plants — including charcoal as identified by its microstructure — as well as conglomerations of charcoal and associated minerals embedded within fossilized hunks of Prototaxites fungi. Those samples came from rocks of known ages that formed from sediments dumped just offshore of ancient landmasses. This wildfire debris was carried offshore in streams or rivers before it settled, accumulated and was preserved, the researchers suggest.

      The microstructure of this fossilized and partially charred bit of plant unearthed in Poland from sediments that are almost 425 million years old reveals that it was burnt by some of Earth’s earliest known wildfires.Ian Glasspool/Colby College

      The discovery adds to previous evidence, including analyses of pockets of fluid trapped in halite minerals formed during the Silurian, that suggests that atmospheric oxygen during that time approached or even exceeded the 21 percent concentration seen today, the pair note.

      “The team has good evidence for charring,” says Lee Kump, a biogeochemist at Penn State who wasn’t involved in the new study. Although its evidence points to higher oxygen levels than some models suggest for that time, it’s possible that oxygen was a substantial component of the atmosphere even earlier than the Silurian, he says.

      “We can’t rule out that oxygen levels weren’t higher even further back,” says Kump. “It could be that plants from that era weren’t amenable to leaving a charcoal record.” More

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      Western wildfires’ health risks extend across the country

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      After a relaxing day at the Jersey Shore last July, Jessica Reeder and her son and daughter headed back home to Philadelphia. As they crested a bridge from New Jersey into Pennsylvania, they were greeted with a hazy, yellow-gray sky. It reminded Reeder of the smoky skies she saw growing up in Southern California on days when fires burned in the dry canyons.

      Smelling smoke and worried about her asthma and her kids, Reeder flipped the switch to recirculate the air inside the car instead of drawing from the outside. At home, the family closed all the windows and turned their air purifiers on high.

      The smoke had traveled from fires raging on the other side of the continent, in the western United States and Canada. Although air quality in Philadelphia didn’t come close to the record-bad air quality that some western cities experienced, it was bad enough to trigger air quality warnings — and not just for people with asthma or heart problems.

      Most large U.S. wildfires occur in the West. But the smoke doesn’t stay there. It travels eastward, affecting communities hundreds to thousands of kilometers away from the fires. In fact, the majority of asthma-related deaths and emergency room visits attributed to fire smoke in the United States occur in eastern cities, according to a study in the September 2021 GeoHealth.

      Smoke poured into the eastern United States and Canada from wildfires in the West on July 21, 2021 (darker red is denser smoke). Residents of eastern cities received code orange and code red warnings that air quality was unhealthy.Joshua Stevens/NASA Earth Observatory

      The big problem is fine particulate matter, tiny particles also known as PM2.5. These bits of ash, gases and other detritus suspended in smoke are no more than 2.5 micrometers wide, small enough to lodge in the lungs and cause permanent damage. PM2.5 exacerbates respiratory and cardiovascular problems and can lead to premature death. The particles can also cause asthma and other chronic conditions in otherwise healthy adults and children.

      Over the last few decades, U.S. clean air regulations have cut down on particulate matter from industrial pollution, so the air has been getting cleaner, especially in the populous eastern cities. But the regulations don’t address particulate matter from wildfire smoke, which recent studies show is chemically different from industrial air pollution, potentially more hazardous to humans and increasing significantly.

      So far, a lot of the research on how wildfire PM2.5 can make people sick has been based on people living or working near fires in the West. Now, researchers are turning their attention to how PM2.5 from smoke affects the big population centers in the East, far from the wildfires. One thing is clear: With the intensity and frequency of wildfires increasing due to climate change (SN: 12/19/20 & 1/2/21, p. 32), people across North America need to be concerned about the health impacts, says Katelyn O’Dell, an atmospheric scientist at George Washington University in Washington, D.C.

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      Bad air travels

      Air pollution regulations limit PM2.5 from exhaust-emitting cars and trucks and fossil fuel–burning factories and power plants. These regulations have done “a really good job” reducing anthropogenic air pollution in the last couple of decades, says Rosana Aguilera, an environmental scientist at the Scripps Institution of Oceanography in La Jolla, Calif. In the United States, concentrations of six of the most common air pollutants have dropped by 78 percent since the Clean Air Act of 1970, according to the U.S. Environmental Protection Agency. PM2.5 concentrations have come down as well — at least until recently.

      Western wildfires, which are growing more frequent, more severe and larger, are erasing some of the gains made in reducing industrial pollution, says Rebecca Buchholz, an atmospheric chemist at the National Center for Atmospheric Research in Boulder, Colo.

      Fires in the Pacific Northwest are “driving an upward trend” in particulate matter air pollution, Buchholz and colleagues wrote April 19 in Nature Communications. Such smoke pollution peaks in August when fires in the region tend to spike and the atmosphere’s ability to clean itself through, say, rain, is limited. This spike of late-summer air pollution is new, Buchholz says. It’s especially noticeable since 2012.

      New York City, visible through hazy skies in September 2020, and many places in the East have seen some of the worst air quality in decades due to fires burning in the U.S. West and in Canada. Such fires are increasing in intensity and frequency.Gary Hershorn/Getty Images plus

      And, as Reeder and her family experienced last year, transported wildfire pollution is causing substantial particulate matter spikes in the central United States and northeastern North America, Buchholz and colleagues found. Pacific Northwest wildfires thus “have the potential to impact surface air quality, even at large distances downwind of the wildfires,” the team wrote, putting some 23 million people in the central United States and 72 million in northeastern North America at increased risk of health impacts from the imported wildfire smoke.

      How far and where PM2.5 travels depends on weather patterns and how high wildfire smoke reaches — the stronger the fire, the longer it can last and the farther smoke can go, and thus the farther particulate matter can reach. Last year, far-away wildfires created unhealthy air quality conditions in locations from the Great Plains to New York City and Washington, D.C.

      New York City saw some of its worst air quality in two decades. Philadelphia had two “code red” days — meaning air quality was unhealthy for all — because of the U.S. West and Canadian fires. In 2019, 2020 and 2021, those fires pushed PM2.5 to unhealthy levels in much of Minnesota. In fact, a 2018 study showed that wildfire smoke plumes now waft above Minnesota for eight to 12 days per month between June and September.

      Human impacts

      Smoke in the West is already having a tangible effect on human health in the East, says O’Dell, lead author of the 2021 GeoHealth study.

      Reviewing smoke and health data from 2006 to 2018, O’Dell and colleagues found that more people visit emergency rooms and are hospitalized in the East than in the West from asthma problems attributable to smoke PM2.5. Asthma-related ER visits and hospitalizations were higher east of the Rockies in 11 of the 13 years.

      Over the study period, an average of 74 percent of asthma-related deaths and 75 percent of asthma ER visits and hospitalizations attributable to smoke occurred east of the Rockies. Of the estimated 6,300 excess deaths from asthma complications due to smoke PM2.5 that occurred annually over the study period, more than 4,600 were in the East.

      Smoke affects so many more people in the East primarily because more people live there, O’Dell notes. Her team defined “West” as west of the Rockies, with a population of 64 million, and “East” as east of the Rockies, home to 226 million people. In the West, smoke PM2.5 causes a higher portion of regional asthma deaths. In the East, it’s a lower portion of the total population, but a far higher total number of people affected.

      “We may be already seeing the consequences of these fires on the health of residents who live hundreds or even thousands of miles downwind,” Buchholz said in a press release.

      Vulnerable youth

      “Asthma is a very widespread, common health condition,” says Yang Liu, an environmental scientist at Emory University in Atlanta. In the United States, about 25 million people have asthma, or 8 percent of adults and 7 percent of children, according to the U.S. Centers for Disease Control and Prevention.

      Fine particulate matter can spark asthma attacks, but it can also be a danger to people without the condition. Children are especially vulnerable primarily because of physiology. Children breathe faster so they end up taking in more particulate matter, plus their lungs are smaller so more of their lung surface is likely to be damaged when they breathe in particulate matter. And their lungs are still developing, says Jennifer Stowell, an environmental epidemiologist at Boston University School of Public Health.

      Stowell led a study, reported in the January Environmental Research Letters, estimating how much wildfire smoke will exacerbate asthma attacks in the West. Stowell, Liu and colleagues estimate that, in the 2050s, there will be an additional 155,000 asthma-related ER visits and hospitalizations per wildfire season in the West just from smoke PM2.5. The biggest concern, Stowell says, is for children and younger adults.

      Aguilera, of Scripps, and her colleagues found associations between wildfire-specific PM2.5 and pediatric respiratory-related ER and urgent care visits. In San Diego County from 2011 to 2017, wildfire-specific PM2.5 was 10 times as harmful to respiratory health in children 5 and younger as ambient PM2.5, the researchers reported in 2021 in Pediatrics. In fact, the same increase in levels of PM2.5 from smoke versus ambient sources caused a 26 percent higher rate of ER or urgent care visits. The researchers didn’t note whether the children had preexisting asthma.

      And even when a wildfire increased PM2.5 by a small amount, respiratory ER and urgent care visits in kids 12 and under increased, Aguilera and colleagues reported in 2020 in the Annals of the American Thoracic Society. “Even relatively smaller wildfires can still generate quite an impact on the pediatric population,” Aguilera says. “And really, any amount of PM or air pollution is harmful.”

      Studies of nonhuman primates have also shown permanent effects of smoke on the young — results researchers expect would also apply to humans, given genetic similarities. In 2008, a group of infant rhesus macaques at the California National Primate Research Center at the University of California, Davis was exposed to high PM2.5 levels from a series of devastating wildfires in Northern California. Researchers have been comparing those monkeys with macaques born a year later that weren’t exposed to smoke.

      At the California National Primate Research Center, rhesus macaques that were exposed to wildfire smoke early in life have immune disorders, nervous system changes and weakened lungs. © 2014 Kathy West/California National Primate Research Center/UC Davis

      At around age 3, macaques exposed to smoke displayed immune disorders and reduced lung capacity, lung function and lung volume, says Hong Ji, a molecular biologist at UC Davis and the primate center who wasn’t involved with this study. The lungs look like they had fibrosis, Ji says. “Early life smoke exposure … changed the trajectory of lung development,” and it doesn’t appear to be reversible, she says.

      The monkeys exposed to wildfire PM2.5 also have important changes to how their DNA works, Ji and colleagues reported in the January Environment International. Exposure to wildfire smoke in infancy can cause life-altering, long-term changes to the monkeys’ nervous and immune systems, as well as brain development, Ji says. Even worse, she says, the DNA changes are the type that can be passed down and may result in generational damage.

      Even macaques born after in utero exposure to wildfire smoke can suffer cognitive, immune and hormone problems, primate center researchers reported April 1 in Nature Communications.

      Now, Ji and colleagues have teamed with Rebecca Schmidt, a molecular epidemiologist at UC Davis who’s leading a study on the effects of wildfire smoke exposure on pregnant women and young children. This research group, as well as other teams, is also looking into whether PM2.5 is causing genetic changes to babies exposed to smoke in utero, Ji says. The more results gathered on the effects of wildfire PM2.5 on babies and children — and even in pregnancy — the more dangerous we realize it is, Ji says.

      Chemical differences

      Particulate matter changes as it travels through the atmosphere, both in volume and in chemistry. Some PM2.5 is emitted directly from fires, and some is born from chemicals and trace gases emitted from fires that get chemically processed in the atmosphere, Buchholz says. Reactions that happen in the smoke plume, combined with sunlight, can create even more PM2.5 downwind of the fires. How these particulates change chemically — through interactions between the atmosphere and the particulate matter, and between fire pollution and human pollution — and what that means for human health “is a really active area of research right now,” she says. “It’s super complicated.”

      Epidemiological and atmospheric chemistry studies indicate that wildfire PM2.5 is more hazardous to human health than ambient PM2.5, says Stowell, the Boston epidemiologist. One such study compared particulate matter from Amazonian fires with urban sources such as vehicle exhaust in Atlanta. Nga Lee Ng, an atmospheric chemist at Georgia Tech, and colleagues found that smoke particulate matter is more toxic than urban particulate matter, “inducing about five times higher cellular oxidative stress,” Ng says. Oxidative stress damages cells and DNA in the body.

      In addition, as smoke travels through the atmosphere and ages, it seems to become even more toxic, Ng says. Reactions between the particulate matter and sunlight and atmospheric gases change the particulate matter’s chemical and physical properties, rendering it even more potentially harmful. So, even though particulate matter dissipates over time and distance, “the health effects per gram are greater,” says Daniel Jaffe, an atmospheric chemist at the University of Washington Bothell.

      That means that the studies of health effects near wildfires in the West may not represent the full story of how smoke from distant fires affects people in the East.

      Liu, at Emory, hopes to see the U.S. government revisit policies related to what PM2.5 levels are dangerous, since they’re based on ambient and not wildfire-related PM2.5. In March, an EPA advisory panel recommended just that. In a letter to the agency, the Clean Air Scientific Advisory Committee wrote: “Regarding the annual PM2.5 standard, all CASAC members agree that the current level of the annual standard is not sufficiently protective of public health and should be lowered.” The committee added, “There is substantial epidemiologic evidence from both morbidity and mortality studies that the current standard is not adequately protective.”

      Local communities throughout the country need to determine when to close schools or at least keep kids inside, Liu says, as well as when to advise people to close windows and turn on air purifiers. Good masks — N95 and KN95 — can help too (yes, masks that block viruses can also block particulate matter).

      City, county and state governments also need to prepare the health care system to respond to increased asthma issues, Liu says. Some states are starting to respond. In 2017, for example, the Minnesota Pollution Control Agency increased its air quality monitoring stations around the state from two to 18. The agency is also working with the National Weather Service, the Minnesota Department of Health and the Minnesota Department of Transportation to better communicate air quality warnings.

      Minnesota, after experiencing a rise in smoky summer days, has added extra air quality monitoring stations to improve local forecasts.Minnesota Pollution Control Agency

      In the meantime, much more research is needed into the human health implications of increasing wildfire smoke, Buchholz says, as well as the chemical interactions in the atmosphere, how climate is changing fires, how fires change year after year, and how they impact the atmosphere, not to mention how different trees, buildings and other fuels affect particulate matter.

      “Wildfires are perhaps one of the most visible ways that [climate change] is linked to health,” Stowell says. And the reality is, she says, “we’re going to see it remain as bad or worse for a while.” More

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      Ancient penguin bones reveal unprecedented shrinkage in key Antarctic glaciers

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      Antarctica’s Pine Island and Thwaites glaciers are losing ice more quickly than they have at any time in the last few thousand years, ancient penguin bones and limpet shells suggest.

      Scientists are worried that the glaciers, two of Antarctica’s fastest-shrinking ones, are in the process of unstable, runaway retreat. By reconstructing the history of the glaciers using the old bones and shells, researchers wanted to find out whether these glaciers have ever been smaller than they are today.

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      “If the ice has been smaller in the past, and did readvance, that shows that we’re not necessarily in runaway retreat” right now, says glacial geologist Brenda Hall of the University of Maine in Orono. The new result, described June 9 in Nature Geoscience, “doesn’t give us any comfort,” Hall says. “We can’t refute the hypothesis of a runaway retreat.”

      Pine Island and Thwaites glaciers sit in a broad ocean basin shaped like a bowl, deepening toward the middle. This makes the ice vulnerable to warm currents of dense, salty water that hug the ocean floor (SN: 4/9/21). Scientists have speculated that as the glaciers retreat farther inland, they could tip into an irreversible collapse (SN: 12/13/21).  That collapse could play out over centuries and raise the sea level by roughly a meter.

      Researchers dated ancient shorelines (seen here as the series of small ridges in the rocky terrain between the foreground boulders and background snow) on islands roughly 100 kilometers from Pine Island and Thwaites glaciers in Antarctica to help figure out if the glaciers are in the process of unstable, runaway retreat.James Kirkham

      To reconstruct how the glaciers have changed over thousands of years, the researchers turned to old penguin bones and shells, collected by Scott Braddock, a glacial geologist in Hall’s lab, during a research cruise in 2019 on the U.S. icebreaker Nathaniel B. Palmer.

      One afternoon, Braddock clambered from a bobbing inflatable boat onto the barren shores of Lindsey 1 — one of a dozen or more rocky islands that sit roughly 100 kilometers from where Pine Island Glacier terminates in the ocean. As he climbed the slope, his boots slipped over rocks covered in penguin guano and dotted with dingy white feathers. Then, he came upon a series of ridges — rocks and pebbles that were piled up by waves during storms thousands of years before — that marked ancient shorelines.

      Twelve thousand years ago, just as the last ice age was ending, this island would have been entirely submerged in the ocean. But as nearby glaciers shed billions of metric tons of ice, the removal of that weight allowed Earth’s crust to spring up like a bed mattress — pushing Lindsey 1 and other nearby islands out of the water, a few millimeters per year.

      As Lindsey 1 rose, a series of shorelines formed on the edges of the island — and then were lifted, one after another, out of reach of the waves. By measuring the ages and heights of those stranded shorelines, the researchers could tell how quickly the island had risen. Because the rate of uplift is determined by the amount of ice being lost from nearby glaciers, this would reveal how quickly Pine Island and Thwaites glaciers had retreated — and whether they had gotten smaller than they are today and then readvanced.

      Braddock dug into the pebbly ridges, collecting ancient cone-shaped limpet shells and marble-sized fragments of penguin bones deposited when the shorelines formed. Back in Maine, he and his colleagues radiocarbon dated those objects to estimate the ages of the shorelines. Ultimately, the researchers dated nearly two dozen shorelines, spread across several islands in the region.

      These dates showed that the oldest and highest beach formed 5,500 years ago. Since that time, up until the last few decades, the islands have risen at a steady rate of about 3.5 millimeters per year. This is far slower than the 20 to 40 millimeters per year that the land around Pine Island and Thwaites is currently rising, suggesting that the rate of ice loss from nearby glaciers has skyrocketed due to the onset of rapid human-caused warming, after thousands of years of relative stability.

      “We’re going into unknown territory,” Braddock says. “We don’t have an analog to compare what’s going on today with what happened in the past.”

      Slawek Tulaczyk, a glaciologist at the University of California, Santa Cruz, sees the newly dated shorelines as “an important piece of information.” But he cautions against overinterpreting the results. While these islands are 100 kilometers from Pine Island and Thwaites, they are less than 50 kilometers from several smaller glaciers — and changes in these closer glaciers might have obscured whatever was happening at Pine Island and Thwaites long ago. He suspects that Pine Island and Thwaites could still have retreated and then readvanced a few dozen kilometers: “I don’t think this study settles it.” More

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      Growing wildfire threats loom over the birthplace of the atomic bomb

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      There are things I will always remember from my time in New Mexico. The way the bark of towering ponderosa pines smells of vanilla when you lean in close. Sweeping vistas, from forested mountaintops to the Rio Grande Valley, that embellish even the most mundane shopping trip. The trepidation that comes with the tendrils of smoke rising over nearby canyons and ridges during the dry, wildfire-prone summer months.

      There were no major wildfires near Los Alamos National Laboratory during the year and a half that I worked in public communications there and lived just across Los Alamos Canyon from the lab. I’m in Maryland now, and social media this year has brought me images and video clips of the wildfires that have been devastating parts of New Mexico, including the Cerro Pelado fire in the Jemez Mountains just west of the lab.

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      Wherever they pop up, wildfires can ravage the land, destroy property and displace residents by the tens of thousands. The Cerro Pelado fire is small compared with others raging east of Santa Fe — it grew only to the size of Washington, D.C. The fire, which started mysteriously on April 22, is now mostly contained. But at one point it came within 5.6 kilometers of the lab, seriously threatening the place that’s responsible for creating and maintaining key portions of fusion bombs in our nation’s nuclear arsenal.

      That close call may be just a hint of growing fire risks to come for the weapons lab as the Southwest suffers in the grip of an epic drought made worse by human-caused climate change (SN: 4/16/20). May and June typically mark the start of the state’s wildfire season. This year, fires erupted in April and were amplified by a string of warm, dry and windy days. The Hermits Peak and Calf Canyon fires east of Santa Fe have merged to become the largest wildfire in New Mexico’s recorded history.

      Los Alamos National Lab is in northern New Mexico, about 56 kilometers northwest of Santa Fe. The lab’s primary efforts revolve around nuclear weapons, accounting for 71 percent of its $3.9 billion budget, according the lab’s fiscal year 2021 numbers. The budget covers a ramp-up in production of hollow plutonium spheres, known as “pits” because they are the cores of nuclear bombs, to 30 per year beginning in 2026. That’s triple the lab’s current capability of 10 pits per year. The site is also home to radioactive waste and debris that has been a consequence of weapons production since the first atomic bomb was built in Los Alamos in the early 1940s (SN: 8/6/20).

      What is the danger due to fire approaching the lab’s nuclear material and waste? According to literature that Peter Hyde, a spokesperson for the lab, sent to me to ease my concern, not much.

      Over the last 3½ years, the lab has removed 3,500 tons of trees and other potential wildfire fuel from the sprawling, 93-square-kilometer complex. Lab facilities, a lab pamphlet says, “are designed and operated to protect the materials that are inside, and radiological and other potentially hazardous materials are stored in containers that are engineered and tested to withstand extreme environments, including heat from fire.”

      What’s more, most of roughly 20,000 drums full of nuclear waste that were stored under tents on the lab’s grounds have been removed. They were a cause for anxiety during the last major fire to threaten the lab in 2011. According to the most recent numbers on the project’s website, all but 3,812 of those drums have been shipped off to be stored 655 meters underground at the Waste Isolation Pilot Plant near Carlsbad, N.M.

      But there’s still 3,500 cubic meters of nuclear waste  in the storage area, according to a March 2022 DOE strategic planning document for Los Alamos. That’s enough to fill 17,000 55-gallon drums. So potentially disastrous quantities of relatively exposed nuclear waste remain at the lab — a single drum from the lab site that exploded after transport to Carlsbad in 2014 resulted in a two-year shutdown of the storage facility. With a total budgeted cleanup cost of $2 billion, the incident is one of the most expensive nuclear accidents in the nation’s history.

      Since the 2011 fire, a wider buffer space around the tents has been cleared of vegetation. In conjunction with fire suppression systems, it’s unlikely that wildfire will be a danger to the waste-filled drums, according to a 2016 risk analysis of extreme wildfire scenarios conducted by the lab.

      But a February 2021 audit by the U.S. Department of Energy’s Office of Inspector General is less rosy. It found that, despite the removal of most of the waste drums and the multiyear wildfire mitigation efforts that the lab describes, the lab’s wildfire protection is still lacking.

      According to the 20-page federal audit, the lab at that time had not developed a “comprehensive, risk-based approach to wildland fire management” in accordance with federal policies related to wildland fire management. The report also noted compounding issues, including the absence of federal oversight of the lab’s wildfire management activities.

      A canyon on lab grounds that runs alongside the adjacent city of Los Alamos (two spots shown) was called out in an audit by the Department of Energy’s Office of Inspector General because it was packed with about 400 to 500 trees per acre. The ideal number from a wildfire management viewpoint is 40 to 50 trees per acre.The Department of Energy’s Wildland Fire Prevention Efforts at the Los Alamos National Laboratory

      Among the ongoing risks, not all fire roads were maintained well enough to provide a safe route for firefighters and others, “which could create dangerous conditions for emergency responders and delay response times,” the auditors wrote.

      And a canyon that runs between the lab and the adjacent town of Los Alamos was identified in the report as being packed with 10 times the number of trees that would be ideal, from a wildfire safety perspective. To make matters worse, there’s a hazardous waste site at the bottom of the canyon that could, the auditors wrote, “produce a health risk to the environment and to human health during a fire.”

      “The report was pretty stark,” says Edwin Lyman, director of nuclear power safety at the Union of Concerned Scientists. “And certainly, after all the warnings, if they’re still not doing all they need to do to fully mitigate the risk, then that’s just foolishness.”

      A 2007 federal audit of Los Alamos, as well as nuclear weapons facilities in Washington state and Idaho, showed similar problems. In short, it seems little has changed at Los Alamos in the 14-year span between 2007 and 2021. Lab spokespeople did not respond to my questions about the lab’s efforts to address the specific problems identified in the 2021 report, despite repeated requests. 

      The Los Alamos area has experienced three major wildfires since the lab was founded — the Cerro Grande fire in 2000, Las Conchas in 2011 and Cerro Pelado this year. But we probably can’t count on 11-year gaps between future wildfires near Los Alamos, according to Alice Hill, the senior fellow for energy and the environment with the Council on Foreign Relations, who’s based in Washington, D.C.

      The changing climate is expected to dramatically affect wildfire risks in years to come, turning Los Alamos and surrounding areas into a tinderbox. A study in 2018 in Climatic Change found that the region extending from the higher elevations in New Mexico, where Los Alamos is located, into Colorado and Arizona will experience the greatest increase in wildfire probabilities in the Southwest. A new risk projection tool that was recommended by Hill, called Risk Factor, also shows increasing fire risk in the Los Alamos area over the next 30 years.

      “We are at the point where we are imagining, as we have to, things that we’ve never experienced,” Hill says. “That is fundamentally different than how we have approached these problems throughout human history, which is to look to the past to figure out how to be safer in the future…. The nature of wildfire has changed as more heat is added [to the planet], as temperatures rise.”

      Increased plutonium pit production will add to the waste that needs to be shipped to Carlsbad. “Certainly, the radiological assessments in sort of the worst case of wildfire could lead to a pretty significant release of radioactivity, not only affecting the workers onsite but also the offsite public. It’s troubling,” says Lyman, who suggests that nuclear labs like Los Alamos should not be located in such fire-prone areas.

      The Los Alamos Neutron Science Center (shown in March of 2019), a key facility at Los Alamos National Laboratory, was evacuated in March 2019 when power lines sparked a nearby wildfire. It could be damaged or even destroyed if a high-intensity wildfire burned through a nearby heavily forested canyon, according to an audit by the Department of Energy’s Office of Inspector General.The Department of Energy’s Wildland Fire Prevention Efforts at the Los Alamos National Laboratory

      For now, some risks from the Cerra Pelado wildfire will persist, according to Jeff Surber, operations section chief for the U.S. Department of Agriculture Forestry Service’s efforts to fight the fire. Large wildfires like Cerra Pelado “hold heat for so long and they continue to smolder in the interior where it burns intermittently,” he said in a May 9 briefing to Los Alamos County residents, and to concerned people like me watching online.

      It will be vital to monitor the footprint of the fire until rain or snow finally snuffs it out late in the year. Even then, some danger will linger in the form of “zombie fires” that can flame up long after wildfires appear to have been extinguished (SN: 5/19/21). “We’ve had fires come back in the springtime because there was a root underground that somehow stayed lit all winter long,” said Surber.

      So the Cerro Pelado fire, and its occasional smoky tendrils, will probably be a part of life in northern New Mexico for months still. And the future seems just as fiery, if not worse. That’s something all residents, including the lab, need to be preparing for.

      Meantime, if you make it out to the mountains of New Mexico soon enough, be sure to sniff a vanilla-flavored ponderosa while you still can. I know I will. More

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      Just 3 ingredients can quickly destroy widely used PFAS ‘forever chemicals’

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      The undoing of toxic “forever chemicals” may be found in products in your pantry.

      Perfluoroalkyl and polyfluoroalkyl substances, also known as PFAS, can persist in the environment for centuries. While the health impacts of only a fraction of the thousands of different types of PFAS have been studied, research has linked exposure to high levels of some of these widespread, humanmade chemicals to health issues such as cancer and reproductive problems.

      Now, a study shows that the combination of ultraviolet light and a couple of common chemicals can break down nearly all the PFAS in a concentrated solution in just hours. The process involves blasting UV radiation at a solution containing PFAS and iodide, which is often added to table salt, and sulfite, a common food preservative, researchers report in the March 15 Environmental Science & Technology.

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      “They show that when [iodide and sulfite] are combined, the system becomes a lot more efficient,” says Garrett McKay, an environmental chemist at Texas A&M University in College Station who was not involved in the study. “It’s a big step forward.”

      A PFAS molecule contains a chain of carbon atoms that are bonded to fluorine atoms. The carbon-fluorine bond is one the strongest known chemical bonds. This sticky bond makes PFAS useful for many applications, such as water- and oil-repellant coatings, firefighting foams and cosmetics (SN: 6/4/19; SN: 6/15/21). Owing to their widespread use and longevity, PFAS have been detected in soils, food and even drinking water. The U.S. Environmental Protection Agency sets healthy advisory levels for PFOA and PFOS — two common types of PFAS — at 70 parts per trillion.

      Treatment facilities can filter PFAS out of water using technologies such as activated carbon filters or ion exchange resins. But these removal processes concentrate PFAS into a waste that requires a lot of energy and resources to destroy, says study coauthor Jinyong Liu, an environmental chemist at the University of California, Riverside. “If we don’t [destroy this waste], there will be secondary contamination concerns.”

      One of the most well-studied ways to degrade PFAS involves mixing them into a solution with sulfite and then blasting the mixture with UV rays. The radiation rips electrons from the sulfite, which then move around, snipping the stubborn carbon-fluorine bonds and thereby breaking down the molecules.

      But some PFAS, such as a type known as PFBS, have proven difficult to degrade this way. Liu and his colleagues irradiated a solution containing PFBS and sulfite for an entire day, only to find that less than half of the pollutant in the solution had broken down. Achieving higher levels of degradation required more time and additional sulfite to be poured in at spaced intervals.

      The researchers knew that iodide exposed to UV radiation produces more bond-cutting electrons than sulfite. And previous research has demonstrated that UV irradiation paired with iodide alone could be used to degrade PFAS chemicals.

      So Liu and his colleagues blasted UV rays at a solution containing PFBS, iodide and sulfite. To the researchers’ surprise, after 24 hours of irradiation, less than 1 percent of the stubborn PFBS remained.

      What’s more, the researchers showed that the process destroyed other types of PFAS with similar efficiency and was also effective when PFAS concentrations were 10 times that which UV light and sulfite alone could degrade. And by adding iodide the researchers found that they could speed up the reaction, Liu says, making the process that much more energy efficient.

      In the solution, iodide and sulfite worked together to sustain the destruction of PFAS molecules, Liu explains. When UV rays release an electron from iodide, that iodide is converted into a reactive molecule which may then recapture freed electrons. But here sulfite can step in and bond with these reactive molecules and with electron-scavenging oxygen in the solution. This sulfite “trap” helps keep the released electrons free to cut apart PFAS molecules for eight times longer than if sulfite wasn’t there, the researchers report.

      It’s surprising that no one had demonstrated the effectiveness of using sulfite with iodide to degrade PFAS before, McKay says.

      Liu and his colleagues are now collaborating with an engineering company, using their new process to treat PFAS in a concentrated waste stream. The pilot test will conclude in about two years. More