Trained dogs can sniff out a deadly deer disease

The proof-of-concept investigation by University of Pennsylvania researchers suggests detection dogs could be an asset in the effort to identify, contain, and manage chronic wasting disease, a highly contagious ailment

Peer-Reviewed Publication

UNIVERSITY OF PENNSYLVANIA

Charlie, Jari, and Kiwi are pet dogs with a superpower: Their sensitive noses can distinguish between a healthy deer and one sick with chronic wasting disease (CWD), all from a whiff of the deer’s poop.

That’s the finding of a study by scientists from Penn’s School of Veterinary Medicine, published in the journal Prion. Using feces samples from CWD-positive deer and deer in which CWD was not detected, the researchers trained the dogs to identify the odor of CWD, alerting their handlers to its presence in the lab and in the field.

“We were already quite certain that the dogs could detect the volatile organic compounds released by chronic wasting disease in feces,” says Amritha Mallikarjun, a postdoctoral researcher in Penn Vet’s Working Dog Center and lead author on the study. “Not only did we show this was possible, but we also answered a second, more interesting question, which is, Can they detect the disease in a simulated field setting, as they would if we were using the dogs to find the disease in the landscape of a forest or on a deer farm?”

The dogs indeed could, with enough accuracy to suggest that detection dogs could be a useful strategy in the fight to manage CWD.

“We learned a lot through the study and are now set up well to continue refining our training,” says Cynthia Otto, the senior author on the study and director of the Working Dog Center.

CWD is a disease that affects a variety of deer species, including white-tailed deer, mule deer, and elk. Always fatal and highly contagious, the disease can hide away in an affected animal for a year or two before symptoms manifest: the deer losing weight—“wasting”—and developing neurological signs, like stumbling and drooling. No cure or treatment exists.

The disease has been in Pennsylvania since 2012, and the state has invested significantly in trying to contain it, with several tools in place for keeping tabs on its spread. One hurdle is figuring out which deer are affected. A healthy-looking but infected animal could shed prions, malformed and infectious proteins, for many months or even years before succumbing to the illness. What’s more, prions are known to bind to soil, potentially contaminating the land on which other animals may roam.

The gold-standard diagnostic test can only be performed after death by assessing an affected animal’s brain. Some alternative tests have been trialed that involve taking a biopsy from a potentially infected animal while it’s still alive, but deer are known to be highly stressed by being captured, and collecting these samples can be physically and logistically difficult for the people involved as well.

The Working Dog Center, the Pennsylvania Department of Agriculture, and the Wildlife Futures Program, a partnership between Penn Vet and the Pennsylvania Game Commission, were well positioned to try to contribute an additional technique for managing the disease: dogs and their highly sensitive noses. Ideally, dogs trained to discern CWD-positive from CWD-not-detected feces in a forest or deer farm could help state agencies and private landowners understand whether further testing or management would be needed to keep their land and herds free from the disease.

First, scientists had to prove the dogs could make this distinction reliably. The Working Dog Center began by enlisting three dogs from their citizen science program—Labrador retrievers Charlie and Kiwi and Finnish spitz Jari—to train on the Center’s “scent wheel,” a contraption equipped with eight ports, each containing a specific substance or scent.

The dogs proved adept at this task. Once they had been trained, using samples provided by the U.S. Department of Agriculture and processed by the Wildlife Futures Program, the dogs responded with great specificity, passing by the not-detected samples 90-95% of the time. Their sensitivity, however, was not as strong, alerting to just 40% of the positive samples. Overall, the researchers found that the dogs spent more time at the ports containing positive samples than those with not-detected samples, suggesting that they perceived a difference even if they didn’t always produce the trained response, such as a bark or sitting down when they smelled the positive sample.

Moving toward a more naturalistic setting, the researchers then experimented with having the dogs and their handlers try to discern CWD-positive samples placed throughout a large, privately owned field. To avoid contaminating the soil or having the dogs come in contact with the samples, two-gram samples of feces were placed in jars with mesh lids to allow the odor to waft out and then partially buried in the ground in different areas.

The researchers observed that the dogs responded to the positive samples more often than the not-detect samples in the field trial. In total, they detected eight of 11 positive samples in the field, with a false negative rate of 13%. Both handlers and dogs seemed to improve as they went, their accuracy increasing after their first field search.

“Given the amount of time that we trained these dogs and the novel environment, not to mention the fact that these are pet dogs and not trained search dogs, our results are promising,” says Mallikarjun. “As we move forward and work with dogs that are specifically trained to search in a field setting and devote their entire lives to detecting this odor, they are going to do an even better job.”

That’s a step the Wildlife Futures Program is already taking, with canine handlers training “professional” detection dogs how to canvas fields and forests, searching for CWD.

The researchers believe that, while dogs don’t represent a silver bullet in the fight against CWD, they may prove useful as an early warning system, helping fill gaps in knowledge from other monitoring systems and management approaches.

“These dogs could increase the odds of catching an outbreak early,” says Lisa Murphy, a study co-author and co-director of the Wildlife Futures Program.

The Penn Vet team is also collaborating with other groups not only to work with detection dogs but also to identify the odor dogs may be responding to in order to develop other systems for early detection. The lessons learned could be broadly useful.

“If we’re able to tap into what we’ve learned with chronic wasting disease and apply it to other issues in agriculture and conservation, these dogs could be a major asset,” Otto says.

Amritha Mallikarjun is a postdoctoral fellow in the University of Pennsylvania School of Veterinary Medicine.

Lisa Murphy is resident director of PADLS New Bolton Center, a professor of toxicology, associate director of the Institute for Infectious and Zoonotic Diseases, and co-director of the Wildlife Futures Program at Penn’s School of Veterinary Medicine.

Cynthia Otto is a professor of working dog sciences and sports medicine and director of the Working Dog Center in Penn’s School of Veterinary Medicine.

Mallikarjun, Murphy, and Otto’s coauthors were Penn Vet’s Ben Swartz, Sarah A. Kane, Michelle Gibison, Isabella Wilson, Amanda Collins, Madison B. Moore, Ila Charendoff, and Julie Ellis and the U.S. Department of Agriculture’s Tracy Nichols. Mallikarjun is corresponding author on the study. 

The work was supported by the Pennsylvania Department of Agriculture and the Wildlife Futures Program at the University of Pennsylvania School of Veterinary Medicine.

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JOURNAL

Prion

DOI

10.1080/19336896.2023.2169519 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Canine detection of chronic wasting disease (CWD) in laboratory and field settings

ARTICLE PUBLICATION DATE

5-Feb-2023

New ESA journal collection spotlights Black scholarship in ecology

Peer-Reviewed Publication

ECOLOGICAL SOCIETY OF AMERICA

This week, the Ecological Society of America highlights the contributions of Black scholars to 21st-century ecology in a virtual collection of papers: “Advancing ecology through Black voices.”

The authors of the articles in the virtual collection address the exclusionary history of the natural sciences, explore ideologies that perpetuate disparities in environmental engagement, and confront public health injustices that have harmed communities of color.

The idea for the collection sprang from ESA’s Black Ecologists Section, with members seeking to promote the contributions of Black Ecologists to the discipline. “This initiative stemmed from my time as co-chair of the Black Ecologist Section, as we brainstormed on how to elevate our contributions to the rapidly expanding and increasingly relevant field of ecology in society,” said Nyeema Harris, Ph.D., an associate professor of wildlife and land conservation at Yale University.

“We recognized that by combating the historic erasure of Black scholars and disciplinary whitewashing, we could build a more inclusive community of a practice. These efforts also highlighted that our identities directly influence our scholarship and that warrants explicit celebration,” Harris said. “So, this collection is a triumphant union of past, present, and future; acknowledgement of foundational principles that get scrutinized in new ways; contemporary Black thought-leaders melding theories and approaches to advance ecology and the future outcomes resultant for our innovations.” 

The collection features papers published in Frontiers in Ecology and the Environment and Ecological Applications. All of the articles in the collection are open access and have been published under Creative Commons licenses.

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Articles:

The public health implications of gentrification: tick-borne disease risks for communities of color
Samniqueka J. Halsey, Meredith C. VanAcker, Nyeema C. Harris, Kaleea R. Lewis, Lisette Perez, Genee S. Smith

The history of natural history and race: Decolonizing human dimensions of ecology
Maria N. Miriti, Ariel J. Rawson, Becky Mansfield

Redefining American conservation for equitable and inclusive social-environmental management
Nia Morales, Jordan Lee, Milton Newberry, Karen Bailey

Responsibility, equity, justice, and inclusion in dynamic human–wildlife interactions
Nyeema C. Harris, Christine E. Wilkinson, Gabriela Fleury, Zoliswa N. Nhleko

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

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JOURNAL

Frontiers in Ecology and the Environment

Researchers successfully prevent peanut allergic reactions in mice, blocking onset in its tracks

Peer-Reviewed Publication

UNIVERSITY OF NOTRE DAME

 

IMAGE: PHOTO BY MATT CASHORE/UNIVERSITY OF NOTRE DAME view more 

CREDIT: PHOTO BY MATT CASHORE/UNIVERSITY OF NOTRE DAME

An allergen-specific inhibitor devised by researchers at the University of Notre Dame and the Indiana University School of Medicine has successfully prevented potentially life-threatening allergic responses to peanuts.

The results of the new study were just published in Science Translational Medicine.

Peanuts cause severe, sometimes fatal, reactions in an estimated 1.1 percent of the global population. Strict dietary avoidance is the most common therapy for peanut allergies, but the risk of accidental exposure is high. There currently are no therapies to prevent allergic events from happening in the first place.

"Our approach is unique because our inhibitor starts working before the allergen has a chance to trigger an allergic reaction," said Başar Bilgiçer, professor of chemical and biomolecular engineering at the University of Notre Dame. “Our collaboration with Dr. Mark Kaplan at Indiana University School of Medicine and Dr. Scott Smith at Vanderbilt University Medical Center made the development of these inhibitors possible. With their help, we were able to demonstrate the potency of our approach in animal studies.”

Using a cHBI inhibitor that they designed in their previous work, the researchers prevented allergic reactions in mice with human immune cells. A single administration provided protection against peanut allergic reaction for over two weeks. Moreover, when given shortly after the onset of symptoms, the inhibitor stopped the progression of the allergic reaction in its tracks.

When IgE antibodies and peanut allergens interact in an allergic person’s bloodstream, inflammatory mediators such as histamine are released in large quantities throughout the body.

"The release of histamines is meant to fight against invading pathogens, but, in the case of peanut allergy, there is no pathogen, just peanut proteins,” said Bilgiçer.

The new inhibitor effectively masks the immune system’s ability to recognize the allergen, allowing it to fly under the immune system’s radar without initiating a dangerous response or compromising its ability to fight real pathogens.

The researchers developed inhibitors specifically for peanut allergy because it is the most common food allergy, with high prevalence especially in children. Nevertheless, the success of cHBI in this study paves the way for the development of other allergen-specific inhibitors.

“What we’ve developed is a platform technology,” said Bilgiçer. “The same design and engineering principles used in this paper can be applied in developing inhibitors to treat a range of other allergies such as shellfish and penicillin.” 

The research will now advance to preclinical trials.

Other authors of the study include Scott A. Smith from Vanderbilt University Medical Center; Notre Dame doctoral students Jaeho Shin, Jenna Sjoerdsma, Emily K. Bromley and Gyoyeon Hwang; and Nada S. Alakhras, Anthony L. Sinn, Wenwu Zhang and Karen E. Pollock from IU School of Medicine.

 

More from Başar Bilgiçer:

Fighting to Cure Food Allergies

 

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JOURNAL

Science Translational Medicine

DOI

10.1126/scitranslmed.add6373 

ARTICLE TITLE

Peanut Allergen Inhibition Prevents Anaphylaxis in a Humanized Mouse Model

ARTICLE PUBLICATION DATE

8-Feb-2023

Physiological basis of yield in cotton: New “focus on cotton” webcast

Reports and Proceedings

AMERICAN PHYTOPATHOLOGICAL SOCIETY

 

IMAGE: A FIELD OF COTTON TO BE HARVESTED view more 

CREDIT: JOHN L. SNIDER

As the most commonly used natural fiber, cotton is a vital and versatile crop worldwide—grown for fiber, food, and even fuel. However, cotton production has fluctuated in the past decade due to various factors such as cultivar availability and climate change.

A foundational understanding of the physiological basis of yield in cotton is an important first step toward targeted yield improvement by using functional crop traits that are known to determine productivity. In a new “Focus on Cotton” webcast on Grow: Plant Health Exchange, John L. Snider, Associate Professor of Crop Physiology at the University of Georgia, provides an overview of the physiological drivers of yield in cotton and describes some of the factors that can influence each one. Additionally, he presents results from recently completed research with advanced breeding lines in the southeastern United States.

This 29-minute presentation is freely available through the “Focus on Cotton” resource on Grow: Plant Health Exchange—an outreach service of The American Phytopatholgical Society that contains more than 400 webcasts, including presentations from a number of conferences. These resources cover a broad range of aspects of cotton crop management: agronomic practices, diseases, harvest and ginning, insects, irrigation, nematodes, precision agriculture, soil health and crop fertility, and weeds. These webcasts are available to readers open access (without a subscription).

The “Focus on Cotton” homepage also provides access to “Cotton Cultivated,” a resource from Cotton Incorporated that helps users quickly find the most current cotton production information available. These and other resources are freely available courtesy of Cotton Incorporated at www.planthealthexchange.org/cotton/Pages/default.aspx.

To learn more, watch Physiological Basis of Yield in Cotton on Grow: Plant Health Exchange.

 

Follow Grow: Plant Health Exchange and The Cotton Board on Twitter @crop_protection and @TheCottonBoard.

 

About Grow: Plant Health Exchange: Grow: Plant Health Exchange is a nonprofit, freely available, online resource of timely, science-based information on plant health. It’s a place for plant health management professionals to exchange knowledge and discover the latest applied research. Applied researchers generate the content for Grow, sharing their work and amplifying their reach, and plant health practitioners consume the content on Grow, relying on this user-friendly platform to provide proven plant health science. As an outreach service of The American Phytopathological Society, Grow serves the full range of professionals in plant health management.

About the Cotton Board: The Cotton Research & Promotion Act established the Cotton Board as a quasi-governmental, nonprofit entity to serve as the administrator of the Cotton Research & Promotion Program. Funded by America’s cotton producers and importers through the cotton check-off, the program’s research and promotion activities are conducted worldwide by Cotton Incorporated, the Cotton Board’s sole-source contracting organization, to increase the demand for and improve the market position of cotton.

The Cotton Research & Promotion Program continues to work in all areas of cotton’s pipeline—from the field to the consumer—to keep cotton the number-one fiber choice in the United States. For more information about the Cotton Board and the innovative activities stemming from the program, visit www.cottonboard.org.

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DOI

10.1094/GROW-COT-11-22-352 

ARTICLE TITLE

Physiological Basis of Yield in Cotton

New method helps scientists better predict when volcanos will erupt

Peer-Reviewed Publication

CORNELL UNIVERSITY

ITHACA, N.Y. – Cornell University researchers have unearthed precise, microscopic clues to where magma is stored, offering a way to better assess the risk of volcanic eruptions.

In recent years, scientists have used satellite imagery, earthquake data and GPS to search for ground deformation near active volcanoes, but those techniques can be inaccurate in locating the depth of magma storage.

By finding microscopic, carbon dioxide-rich fluids encased in cooled volcanic crystals, scientists can accurately determine – within one hundred meters – where magma is located.

“A fundamental question is where magma is stored in Earth’s crust and mantle,” said Esteban Gazel, professor of engineering and lead author of the study, published in Science Advances. “That location matters because you can gauge the risk of an eruption by pinpointing the specific location of magma, instead of other signals like hydrothermal system of a volcano.”

Gazel notes that speed and precision are essential. “We’re demonstrating the enormous potential of this improved technique in terms of its rapidity and unprecedented accuracy,” he said. “We can produce data within days of the samples arriving from a site, which provides better, near real-time results.”

In volcanic events, magma reaches the Earth’s surface, and it erupts as lava and – depending on how much gas it contains – could be explosive in nature. When deposited as part of the fallout of the eruption, fragmented fine-grained material – called tephra – can be collected and evaluated.

Gazel and doctoral student Kyle Dayton deduced how to use inclusions of carbon dioxide-rich fluids trapped within olivine crystals to precisely indicate depth, as the carbon dioxide density of these inclusions is controlled by pressure.

These fluids can be measured quickly using an instrument to determine – in terms of kilometers – how far down the magma was stored and the depth of the scorching reservoir.

Gazel and Dayton joined a small, elite team of international researchers to study the Cumbre Vieja volcano on La Palma in the Canary Islands. Gazel and Dayton picked through tephra to find crystals, which in turn provide data to improve eruption models and forecasts.

For additional information, see this Cornell Chronicle story.

Cornell University has dedicated television and audio studios available for media interviews.

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JOURNAL

Science Advances

DOI

10.1126/sciadv.ade7641 

Roads, pet dogs and more may pose hidden threat to Africa’s primates

Peer-Reviewed Publication

UNIVERSITY OF COLORADO AT BOULDER

 

IMAGE: THE EYES OF A GREATER BUSHBABY SHINE IN THE LIGHT OF A CAMERA AT NIGHT IN SOUTH AFRICA. view more 

CREDIT: BIRTHE LINDEN

Many of the hallmarks of human civilization—from roads and power lines to pet dogs—are taking a larger-than-expected toll on non-human primates living in Africa, according to two recent studies.

The findings result from a collaboration between the University of Colorado Boulder and three South Africa-based institutions: the University of Venda, Lajuma Research Centre and the conservation organization the Endangered Wildlife Trust (EWT). They take an almost forensic look at what is killing wild animals in South Africa. The country is home to five species of non-human primates, including greater (Otolemur crassicaudatus) and southern lesser (Galago moholis) bushbabies. These primates spend most of their lives in trees, and some are so small they can fit in the palm of your hand. 

In one study, scientists led by Birthe Linden at Lajuma analyzed hundreds of cases in which non-human primates had been killed on roads or around power lines across the country. In a companion paper, the researchers explored the growing risks that domestic dogs pose to the animals.

The research shows that the threats facing the world’s monkeys, apes and other non-human primates aren’t always easy to see, particularly for lesser-studied animals like bushbabies.

“Bushbabies, especially, are an example of species that may be having problems, but we don’t know what they are until we go looking,” said Michelle Sauther, co-author of the two studies and professor of anthropology at CU Boulder.

For her, the results border on personal. 

In the process of studying bushbabies in South Africa for more than a decade, Sauther and her colleagues got to know one male, in particular—a greater bushbaby with one eye who the team nicknamed Bruiser because he reminded them of an old prize fighter.

Then in 2019 Bruiser, who had bad and missing teeth, tried to move on the ground to reach a fig tree with easy-to-grab fruit. A pet dog found and killed him. 

“These are small stories,” Sauther said. “They're not the big stories of conservation, but they really do matter, especially as we have no good data on bushbaby mortality and thus cannot easily judge their conservation status.”

They’re also small stories that likely touch almost all non-human primate species, not just in South Africa but across the continent.

“We found that all South African non-human primates are in one way or the other impacted by human linear infrastructure, such as power lines or roads,” Linden said. 

A samango monkey crosses a simple canopy bridge in South Africa.

CREDIT

Birthe Linden

Roadkill on the rise

Linden, a primatologist from South Africa, first became interested in the hidden dangers facing primates on her almost daily drives to the University of Venda in South Africa’s Soutpansberg Mountains.

She kept seeing samango monkeys (Cercopithecus albogularis) run over on the side of the road. These monkeys are listed in the “Red List of Mammals of South Africa, Swaziland and Lesotho” as “vulnerable,” one step up from “endangered.”

“It's one stretch where the road is quite close to indigenous forest, which is where samango monkeys typically live,” Linden said.

She wondered if a lot more non-human primates could be dying as roadkill than researchers suspected. South Africa is home to more than 675,000 miles (1,090,000 kilometers) of roads and power lines—and the number keeps climbing.

To explore this pervasive threat, Linden and her colleagues drew from a wide range of data sources. They include Road Watch, a citizen science app released by the EWT that allows anyone in South Africa to upload reports of roadkill. In all, the team gathered 483 examples of primates killed on roads or around power lines, some dating back to the late 1990s. Species included the two bushbabies, samango monkeys, chacma baboons (Papio ursinus) and vervet monkeys (Chlorocebus pygerythrus).

Next up, Frank Cuozzo of the Lajuma Research Centre and a research fellow at the University of Pretoria’s Mammal Research Institute led the group in exploring a different kind of peril: domestic dogs. The researchers tracked down 13 reports of greater bushbabies like Bruiser killed by dogs in South Africa since 2014. In one case, humans intentionally released dogs to hunt down a bushbaby that had gotten too close to town.

“These reports are clearly a sliver of what’s actually happening,” said Cuozzo who earned his doctorate in biological anthropology from CU Boulder in 2000. “It’s happening in the towns and suburban areas, in the rural areas, the reserve areas, and it’s happening far more than anyone would think.”

Greater bushbaby seen crossing a canopy bridge in South Africa at night.

CREDIT

Birthe Linden

Why did the monkey cross the road?

The researchers aren’t sure how big of a dent roads, power lines and domestic dogs are making in non-human primate numbers in South Africa or surrounding nations. But they argue that these deaths are important to follow—especially for animals already struggling to survive amid climate change and habitat loss.

Wendy Collinson-Jonker, co-author of the infrastructure study and a researcher at the EWT, noted that these problems are widespread, but the fixes may be surprisingly simple.

Studies have shown, for example, that monkeys and other forest critters can hop across roads safely on “canopy bridges,” such as a rope bridge hanging between trees.

Humans can also keep dogs away from primates by being careful to not leave food out, especially at night. 

“We know the solutions,” Collinson-Jonker said. “It's a case of now getting them implemented.”

As for Bruiser the bushbaby, Sauther noted that his story ended with a small bit of consolation. The team was able to recover his body and collected X-rays that helped reveal a deeper picture of his more than a decade of life—down to the arthritis building up between his joints that likely led him to climb down to the ground.

“We were able to document his whole life story,” Sauther said. “We knew him right to the end."

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ARTICLE TITLE

Domestic Dogs Present a Human-Induced Threat to Thick-tailed Bushbabies (Otolemur crassicaudatus) in Northern South AfricaDomestic Dogs Present a Human-Induced Threat to Thick-tailed Bushbabies (Otolemur crassicaudatus) in Northern South Africa

Tracking ocean microplastics from space

Microplastic pollution can be spotted from space because its traveling companion alters the roughness of the ocean's surface

Peer-Reviewed Publication

UNIVERSITY OF MICHIGAN

Images  //  Video 

New information about an emerging technique that could track microplastics from space has been uncovered by researchers at the University of Michigan. It turns out that satellites are best at spotting soapy or oily residue, and microplastics appear to tag along with that residue.

Microplastics—tiny flecks that can ride ocean currents hundreds or thousands of miles from their point of entry—can harm sea life and marine ecosystems, and they're extremely difficult to track and clean up. However, a 2021 discovery raised the hope that satellites could offer day-by-day timelines of where microplastics enter the water, how they move and where they tend to collect, for prevention and clean-up efforts.

The team noticed that data recorded by the Cyclone Global Navigation Satellite System (CYGNSS), showed less surface roughness—that is, fewer and smaller waves—in areas of the ocean that contain microplastics, compared to clean areas.

In preliminary testing, they used the technique to spot suspected microplastic releases at the mouth of China's Yangtze River and to identify seasonal variations in the Great Pacific Garbage patch, a convergence zone in the North Pacific Ocean where microplastic collect in massive quantities. But until now, the team was unsure about the nature of the relationship between microplastics and surface roughness.

A newly published study in Scientific Reports shows that the anomalies in wave activity are caused not by the plastics themselves, but by surfactants—soapy or oily compounds that are often released along with microplastics and that travel and collect in similar ways once they’re in the water.

Chris Ruf, the Frederick Bartman Collegiate Professor of Climate and Space Science at U-M and an author of the study, explains that a satellite-based tracking tool would be a major improvement over current tracking methods, which rely mainly on spotty reports from plankton trawlers that net microplastics along with their catch.

"NOAA, the Plymouth Marine Lab in the U.K. and other organizations are very aware of what we're doing, but we need to be cautious and fully understand the system's limitations before putting it into widespread use," said Ruf, who also leads CYGNSS.  "These new findings are an important step in that process." 

The research team, which also included former naval architecture and engineering graduate researchers Yukun Sun and Thomas Bakker, gathered the data at U-M’s Aaron Friedman Marine Hydrodynamics Lab. Using the facility's wave tank, they measured the effects of surfactants and microplastic pellets on waves generated both mechanically and by wind from a fan.

They found that, in order for microplastics to affect surface roughness, their concentrations had to be much higher than those typically found even in polluted areas of the ocean. Surfactants, however, had a pronounced effect. The researchers found that surfactant-laden water required more wind to generate waves of a given size, and that those waves dissipated more quickly than they would in clean water. 

Yulin Pan, U-M naval architecture and marine engineering assistant professor and corresponding author on the paper, says that this initial discovery will drive further research into how surfactants and microplastics interact in the ocean. 

"We can see the relationship between surface roughness and the presence of microplastics and surfactants," Pan said. "The goal now is to understand the precise relationship between the three variables."

They plan to use a combination of water sampling, satellite observations and computer modeling to build that understanding. Ultimately, they hope to develop a system that governments, cleanup organizations and others can use to both spot existing microplastics and predict how they're likely to travel through waterways. 

Ruf and other members of the team are featured in the documentary Plastic Earth, which explores the scale of plastic pollution and engineering solutions in development.

The research was supported in part by NASA Science Mission Directorate contract NNL13AQ00C.

Study: Effects of microplastics and surfactants on surface roughness of water waves

(DOI: 10.1038/s41598-023-29088-9)

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JOURNAL

Scientific Reports

DOI

10.1038/s41598-023-29088-9 

Past records help to predict different effects of future climate change on land and sea

Peer-Reviewed Publication

WOODS HOLE OCEANOGRAPHIC INSTITUTION

 

IMAGE: THE INDIAN OCEAN COASTLINE OF KENYA AND SOMALIA IS PICTURED FROM THE INTERNATIONAL SPACE STATION ABOVE THE AFRICAN CONTINENT. A NEW STUDY SHOWS HOW PAST CLIMATE RECORDS ON LAND AND AT THE SEA SURFACE ALLOW SCIENTISTS TO BETTER PREDICT THE EXTENT THAT LAND WILL WARM MORE THAN THE OCEAN – A PHENOMENON CALLED TERRESTRIAL AMPLIFICATION. view more 

CREDIT: ©NASA

Woods Hole, Mass. (February 8, 2023) --Ongoing climate change driven by greenhouse gas emissions is often discussed in terms of global average warming. For example, the landmark Paris Agreement seeks to limit global warming to 1.5 ⁰C, relative to pre-industrial levels.  However, the extent of future warming will not be the same throughout the planet. One of the clearest regional differences in climate change is the faster warming over land than sea. This “terrestrial amplification” of future warming has real-world implications for understanding and dealing with climate change

A new paper studying terrestrial amplification focuses on how geochemical records of past climate on land and at the sea surface allow scientists to better predict the extent to which land will warm more than oceans—and will also get drier—due to current and future greenhouse gas emissions. “The core idea of our study was to look to the past to better predict how future warming will unfold differently over land and sea,” says Alan Seltzer, an assistant scientist in the Marine Chemistry and Geochemistry Department at the Woods Hole Oceanographic Institution (WHOI) and the lead author of the paper.

“One reason why understanding terrestrial amplification matters is that under future global warming, the magnitude of warming that the planet will experience is not going to be the same everywhere,” says Seltzer. “Adding a firm basis to climate model simulations, that is rooted in observations of past climate and basic physics, can tell us about how the regional differences in ongoing and future warming.” Seltzer notes that terrestrial amplification (TA) is analogous to “polar amplification,” a prediction of climate models that higher latitudes will experience more warming than low latitudes.

Although modern observational records are noisy due to big year-to-year variations driven by other parts of the climate system, the prediction of greater warming over land surfaces is now apparent in climate data since the 1980s. The drivers of this terrestrial amplification have been linked to changes in moisture over land and sea, through a theory developed by climate scientists over the past decade. This new study, published Wednesday in the journal Science Advances, “uses paleoclimate data for the first time to evaluate the theory for how land and sea surfaces will be impacted by future warming,” Seltzer says. “The research gives us more certainty in the way models predict regional changes in future warming.”

The paper investigates terrestrial amplification during the Last Glacial Maximum (LGM)—which occurred about 20,000 years ago—in the low latitudes, which they define as 30⁰S–30⁰N. It is in those latitudes, the authors say, where the theoretical basis for TA is most applicable. The authors drew on new compilations of paleoclimate records on land and from the sea surface to estimate the magnitude of TA in the LGM, to compare with climate model simulations and theoretical expectations. Efforts to better understand how cold the continents were in the LGM are an ongoing focus of Seltzer’s research at WHOI, and this new paper builds upon a recent study that used insights from dissolved gases trapped in ancient groundwater as a thermometer for the past land surface.

The authors extended a thermodynamic theory for terrestrial amplification that is based on coupled changes in moist static energy (the potential energy represented by the temperature, moisture content, and elevation of a parcel of air) between land and sea. In the LGM, when sea level was 120 meters lower than today due to the growth of large ice sheets on land, the sea surface was slightly warmer and more humid than it would have been without a change in sea level. By taking this effect into account and drawing on paleoclimate records, the authors were able to directly compare past terrestrial amplification to future predictions. The paper notes that while the mechanisms underlying TA are well understood to arise from fundamental thermodynamic differences between humid air over the ocean and drier air over land, a number of factors—natural variability, observational limitations, thermal lags, and non-CO2 forcings—have previously precluded a precise estimate of TA from 20th century warming. “Narrowing the range of terrestrial amplification will aid in future predictions of low latitude climate change, with relevance to both heat stress and water availability,” the paper states.

Co-author Pierre-Henri Blard says the paper is a “step forward for climate science,” and it will be significant for other scientific fields and the general public. “We show that a simple model, involving humidity and sea level changes, robustly describes the amplification of temperature changes over the continent—at low to mid-latitudes at any time scale—as being 40% larger than over the ocean. This result is important because, while most paleoclimatic archives are located in the ocean, the present and future of humanity crucially rely on our knowledge of continental climates,” says Blard, a Director of Research at the National Center for Scientific Research (CNRS) at the Center for Petrographic and Geochemical Research (CRPG) in Nancy, France.

The research is important “because it helps us make sense of Earth’s past climate record and how to relate it to our models and expectations for the future,” co-author Steven Sherwood says. The paper “should clear up any misconceptions that land and ocean warm or cool at the same rate in different climates—we know otherwise and should use that knowledge. The implications for the future are that Earth’s continents will continue to warm faster than the oceans as global warming continues, until hopefully we reach net zero and bring this to a stop,” says Sherwood, a professor in the ARC Centre of Excellence for Climate Extremes in the University of New South Wales’s Climate Change Research Center, Sydney, Australia.

Co-author Masa Kageyama says she considers the paper important “because it touches on a feature which is ubiquitous in climate change projections, produced by complex climate models: continents warm more than oceans. In this paper, we analyze this feature for a climate change, from the last glacial maximum to present, the amplitude of which is of the same order of magnitude as the expected warming in the next centuries,” says Kageyama, director of research at CNRS’ Climate and Environment Sciences Laboratory (LSCE) at the Pierre Simon Laplace Institute at the University of Paris-Saclay, France.

“It is remarkable that tropical temperature reconstructions, state-of-the-art climate models, and a simple theory relying on the coupled changes of moisture and heat over continents and oceans all converge to provide a robust estimate of terrestrial amplification,” says Kageyama. “In my view, this strengthens the projections for future climate change, and at the same time brings new understanding of past climate changes.”

Funding for this research was provided by a National Science Foundation Division of Earth Sciences award and by the French National Centre for Scientific Research.

Authors:

Alan M. Seltzer1, Pierre Henri Blard2,3, Steven C. Sherwood4, and Masa Kageyama5

Affiliations:

1Department of Marine Chemistry & Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA

2Centre de Recherches Pétrographiques et Géochimiques, CNRS, Université de Lorraine, Vandoeuvre-lès-Nancy, France

3Laboratoire de Glaciologie, Department of Geosciences, Environment, Society, ULB, Brussels, Belgium

4Climate Change Research Centre, University of New South Wales, Sydney, New South Wales, Australia

5Laboratoire des Sciences du Climat et de l'Environnement/Institut Pierre-Simon Laplace, Université Paris-Saclay, Gif-sur-Yvette, France

About Woods Hole Oceanographic Institution

The Woods Hole Oceanographic Institution (WHOI) is a private, non-profit organization on Cape Cod, Massachusetts, dedicated to marine research, engineering, and higher education. Established in 1930, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate an understanding of the ocean’s role in the changing global environment. WHOI’s pioneering discoveries stem from an ideal combination of science and engineering—one that has made it one of the most trusted and technically advanced leaders in basic and applied ocean research and exploration anywhere. WHOI is known for its multidisciplinary approach, superior ship operations, and unparalleled deep-sea robotics capabilities. We play a leading role in ocean observation and operate the most extensive suite of data-gathering platforms in the world. Top scientists, engineers, and students collaborate on more than 800 concurrent projects worldwide—both above and below the waves—pushing the boundaries of knowledge and possibility. For more information, please visit www.whoi.edu

Key takeaways:

•          Terrestrial amplification, which is the phenomenon of greater temperature change over land surfaces than sea surfaces, has important real-world implications for understanding and dealing with climate change.

•          Paleoclimate data and climate models support theoretical predictions of greater temperature changes over land than sea. Better knowledge about terrestrial amplification and related predicted changes in hydroclimate is useful for policymakers in planning for adaptations to future climate change.

•          The paper focuses on how geochemical records of past climate on land and at the sea surface allow scientists to better predict the extent to which land will warm more than oceans—and will also get drier—due to current and future greenhouse gas emissions.

•          The core idea in this paper is how should the magnitude of warming or cooling over land compare to the magnitude of warming or cooling over the sea surface.

•          Under future global warming, the magnitude of warming that the planet will experience is not going to be the same everywhere. Adding a firm basis that is rooted in observations of past climate that can tell us about how the regional differences in warming will change in a warmer world is really valuable.

•          This research uses paleoclimate data for the first time to evaluate the theory for how land and sea surfaces will be impacted by future warming. The research gives scientists more certainty in the way models predict regional changes in future warming.

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JOURNAL

Science Advances

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Terrestrial amplification of past, present, and future climate change

ARTICLE PUBLICATION DATE

8-Feb-2023