Landscape-level surveys are necessary to address large-scale wildlife losses from poaching

by Forschungsverbund Berlin e.V. (FVB)

Annamite striped rabbit. Credit: Tilker/Wilting

Widespread poaching in tropical biodiversity hotspots is causing unprecedented declines in wildlife populations, known as defaunation. A new study published in the journal Diversity & Distributions, provides evidence that large-scale systematic surveys and novel methods of data collection and analysis, are necessary to assess the extent and distribution of poaching and its impact on biodiversity in forest exposed to severe defaunation. Mapping biodiversity in this way will provide information critical to protecting rare species that may still exist in these landscapes. The research was conducted in the Annamite mountains on the border of Laos and Vietnam, an area with an exceptionally high occurrence of endemic species that is threatened by illegal poaching through the setting of wire snares. The research team, led by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), comprised scientists, conservationists and government counterparts, including representatives from WWF-Vietnam and WWF-Laos.

High levels of unsustainable hunting have decimated wildlife populations in many forests in the Annamites. This situation is not unique to Vietnam and Laos—tropical rainforests in other parts of Southeast Asia are also experiencing a similar fate. To protect wildlife communities in these areas, the researchers argue that limited conservation resources must be utilized effectively and that understanding where rare and threatened species still occur will be an important first step to identify priority areas for targeted conservation activities.

The authors provide evidence that surveying biodiversity in defaunated landscapes may require novel approaches. "By conducting systematic surveys at the landscape-scale, we were able to get a better overview of the wildlife communities and a deeper understanding of the underlying factors which influence species distribution," said Andrew Tilker of the Leibniz-IZW and lead author of the study. "We also found that using two complementary survey methods—camera-traps and vertebrate DNA extracted from parasitic blood-sucking leeches—improved our ability to detect species, which is especially important for rare and elusive animals. We then used these data and applied advanced statistical techniques to produce maps of species distributions across the landscape—the first for the Annamites." Ultimately, the researchers expect that biodiversity baselines established through such scientifically-robust approaches will help conservation managers to protect rare and endangered species still present in these landscapes.

"The threat posed by illegal snares to the survival of endemic wildlife cannot be overstated," said Benjamin Rawson, Conservation and Program Development Director of WWF-Vietnam. "WWF is deploying probably the largest effort in the region to get these snares out of the forest and provide wildlife a fighting chance, but the sheer number of wire snares set in the Annamites is alarming."

"With evidence from landscape-level surveys we will now deploy snare-removal teams to freshly identified areas of high biodiversity," says Adrian Klocke, Project Manager of the KfW Development Bank in Germany, which supports the Carbon and Biodiversity Phase 2 project (CarBi II) in the Annamites. CarBi II is implemented by WWF through KfW as part of the International Climate Initiative (IKI) of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU). "Additionally, the results of this study help us identify areas that are not currently protected but which are important for rare species," Klocke adds. "For instance, one interesting result was that a mostly unpatrolled forest area in Laos called the Palé area is a hotspot for numerous endemic and threatened species. We hope that as a part of CarBi II, this area can be protected."

Amphone Phommachak, WWF-Laos Landscape Manager for the Central Annamites, agrees that this type of scientific study is highly valuable. "We need to develop and implement evidence-driven conservation strategies to protect the remarkable biodiversity of the Annamites. There is no doubt that the Central Annamites have been hit hard by intensive snaring, but fortunately, rare and endemic species are still hanging on. There is still time to protect species like the Annamite striped rabbit, but the window of opportunity is rapidly closing. Focusing snare-removal efforts and protecting new areas will hopefully help us prevent further extinctions in the Annamites."

In Southeast Asia, illegal hunting is a more immediate threat to wildlife than forest degradation

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More information: Andrew Tilker et al, Identifying conservation priorities in a defaunated tropical biodiversity hotspot, Diversity and Distributions (2020). DOI: 10.1111/ddi.13029

After a fire, some plants—even weeds—can be better than none

by Samantha Capon, The Conversation FEBRUARY 5, 2020

Credit: Shutterstock

The Invasive Species Council and other observers have argued for weed control as a major priority following bushfires, to promote the recovery of wildlife and damaged ecosystems. The time is right, some say, to wage a serious offensive against weeds before they re-establish and this opportunity is lost.

But perhaps we shouldn't be so hasty to villainize all weeds. There is growing recognition that weeds can, in some cases, support a range of critical ecological functions.

Who decides what's a weed?

There are official lists of weeds in Australia. But for many, the term "weed" is vague, non-scientific and highly subjective. Weeds can be non-native or native species. They're generally considered to be plants that are growing in places, or ways (for example, in high abundance), that are undesirable.

Their "undesirability" may be traced to a wide range of economic, social, cultural, aesthetic and political reasons. From an ecological perspective, weeds are often blamed for stifling native plant growth, altering wildlife habitat and changing ecological processes. Many assume weed control will improve native plant growth, habitat quality and ecosystem function.

In some situations, however, weeds provide valuable ecological functions by, for example, offering food and habitat for wildlife, protecting soils and landforms from erosion and slowing down the movement of water through catchments.

Exotic chinee apple trees (Ziziphus mauritiana) in north-west Australia, for example, protect the burrow systems of native rodents from habitat damage by feral horses.

This kind of benefit is especially likely in very disturbed habitats, such as areas that have been cleared. Other areas of high functional importance in the landscape such as riparian zones – land alongside creeks, streams, gullies, rivers and wetlands—can benefit from some weeds.

Riparian weeds can support rivers and streams by trapping sediments and contaminants washing into channels via run-off. Exotic riparian willows (Salix spp.) can also provide habitat and food sources for aquatic fauna.

One study found invasive chinee apple trees (Ziziphus mauritiana) provide critical refuge habitat for native rodents. Credit: Chris Gardiner CC BY-SA/Wikimedia, CC BY

This may be particularly important for aquatic ecosystem health following fire.

Weeds may also promote regeneration of native plants by helping stabilize soil, providing shade and protecting seedlings from being eaten by animals and pests.

At larger scales, weeds can also enhance the dispersal of native plant seeds. In highly cleared parts of north-eastern New South Wales, for example, camphor laurel trees (Cinnamomum camphora) – an introduced species—can provide habitats for fruit-eating birds that disperse and establish native rainforest plants.

There's a lot we don't know about weeds

In some cases, weeds may be the only plants that grow back well after fires. And some plants—even weeds—may be better than none.

We can't always assume that the presence of weeds is limiting native plant growth. The fact is we don't really know, in most cases, if removing weeds actually results in higher native plant diversity.

What we do know is that ecosystem functions, such as carbon storage and nutrient cycling, tend to increase where more species are present. And this holds true even in weed-infested forests, which often contain more species than their equivalent native ecosystems.

Many assume weeds will flourish in our post-fire landscapes.

Some see this early establishment period as a unique opportunity to banish "undesirable" plants by weeding before they set seed.

Camphor laurel trees can provide bird habitats in areas where a lot of native trees have been cleared. Credit: Shutterstock

There is surprisingly little evidence, however, regarding the effectiveness of most weed control methods over the longer-term. Many weeds can quickly re-establish from soil seed banks, suckers or plant fragments dispersed by wind, water or birds.

We also know very little about how weed control methods themselves might affect ecological processes through soil disturbance and herbicides.

Even where these methods kill one weed, other, potentially more noxious plants may spring up in its place.

When it comes to weeds, question your assumptions

There is much at stake in Australia as we make decisions regarding the restoration of our unique ecosystems after the recent bushfire crisis.

Importantly, however, we can learn by not blindly acting on assumptions and ideologies. We can test assumptions through robust, long term ecological experiments.

Obviously, not all weeds should be retained. Non-native species can and do have negative effects.

However, we now face an opportunity to embark on a more nuanced and open approach to conservation and restoration.

Indeed, in a future that looks little like the past, we must never stop questioning our land management practices.

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Shelter, safest air intake locations during urban pollution events identified

by Gabrielle Stewart, Pennsylvania State University FEBRUARY 5, 2020

Researchers at Penn State find that roofs and the downwind sides of buildings in street canyons have the lowest levels of particulate matter during a single-source pollution event. The findings have implications for improving evacuation plans during a pollution release as well as for informing ventilation system design of urban buildings.  Credit: PIXABAY

Roofs and the downwind sides of buildings in street canyons have the lowest levels of particulate matter during a single-source pollution event, according to Penn State researchers. The findings have implications for improving evacuation plans during a pollution release as well as for informing ventilation system design of urban buildings.

"Previous research has focused on ambient pollution created by traffic," said Jeremy Gernand, assistant professor of industrial health and safety. "We decided to investigate sources of pollution from a point source of particulate matter, such as a chemical spill or an accidental release from a factory."

The researchers investigated a pollutant release scenario to evaluate the safest locations for evacuation and for building design elements such as air intakes. This marks the first study investigating an emission event from a single source near a street canyon.

Monitoring air quality in urban areas can be very important due to high population density and levels of particulates. Street canyons, or places where the street is bounded on both sides by buildings, are important locations for studying air pollution because they are prevalent in urban areas.

Particulates, often referred to as aerosols, are fine solids or liquid droplets suspended in gas. High concentrations in the atmosphere can contribute to mortality rates, because exposure to these particles can exacerbate or cause adverse medical effects. Particulates are released from a variety of natural or human sources, such as cars, construction sites and dust storms.

Researchers in Penn State's Mining Ventilation Laboratory created a 3-D miniature street canyon in a wind tunnel using foam blocks to simulate buildings . Four foam blocks were placed in a two-by-two array, separated by gaps that served as streets.

To ensure the airflow within the wind tunnel matched realistic conditions in an urban area, researchers had to make adjustments. Typically, air in a wind tunnel exhibits laminar flow, meaning it flows smoothly in parallel layers with no eddies or crosscurrents that disrupt the direction of flow. This type of flow can be ideal for testing mechanisms such as airplane wings in simulated high-altitude air.

At lower elevations, however, air behaves very differently. Near the ground, smaller structures like houses and trees and larger buildings, such as skyscrapers, interrupt the smooth flow of air and cause it to become turbulent, or irregular and agitated.

The researchers used low-cost materials like Legos and cardboard spires to create turbulent airflow in a wind tunnel filled with laminar-flowing air.

To simulate a single particulate emission source, researchers used water generated from an ultrasonic humidifier. Because environmental particulates are frequently coated in water, the collisions between water droplets in a wind tunnel experiment and collisions between water-coated particulates outside can be very similar, Gernand said.

To find the areas in the street canyon where particulate levels reached their minimum and maximum concentrations, researchers used the data from the wind-tunnel experiment to create a computer model of the scenario. Computer simulations showed the lowest particulate concentrations were located at the roof and on downwind building facades. At breathing level, the lowest concentrations were found on the leeward—protected—side of the array's transverse channel, the street running perpendicular to the direction of airflow.

The findings have implications for improving evacuation plans and for informing ventilation system design. In the event of a pollution release emergency from a central source, pedestrians should be evacuated to the leeward side of the transverse channel. For installation of new air intakes, portions of roofs furthest away from inner channels, or roads, of street canyons serve as the safest location, the researchers said.

The researchers reported their findings in the journal Air Quality, Atmosphere and Health.

However, given the variety of possible scenarios, these findings represent only a general guideline and will benefit from further investigation, said Gernand. Building upon the cost-effective modeling approach used in this study, future research will consider additional possibilities with the goal of providing more comprehensive safety recommendations.

Researchers develop new bio-inspired wing design for small drones

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More information: Mengfan Li et al, Identifying shelter locations and building air intake risk from release of particulate matter in a three-dimensional street canyon via wind tunnel and CFD simulation, Air Quality, Atmosphere & Health (2019). DOI: 10.1007/s11869-019-00753-1

Bumble bees prefer a low-fat diet

by Technical University Munich FEBRUARY 5, 2020

Using a two-step mechanistical approach that included learning and feeding experiments, the group established a new way to literally keep a close eye on the feeding habits of insects. Credit: Dieter Mahsberg

Bees are an important factor for our environment and our sustenance. Without insect pollination, many plant species—including various crops—cannot reproduce. "Bee mortality therefore affects food supply for human beings," said Professor Sara Leonhardt, who specializes in plant-insect interactions. All of the worldwide more than 20,000 bee species need to be considered. Among these, bumble bees are of particular importance besides the famous honey bee.

"Bees obtain most of their nutrients from their main food sources, which are nectar and pollen. While nectar is mainly a source of carbohydrates, pollen contains most of the other necessary nutrients: proteins, fat, minerals and vitamins. Until today, most bee researchers assumed that bees, like other herbivores, mainly consider the protein content when choosing their food," Professor Leonhardt explained.

Using a two-step mechanistic approach that included learning and feeding experiments, the group established a new way to literally keep a close eye on the feeding habits of insects.

Learning experiments with bumble bees (Bombus terrestris)

Which nutrients can bumble bees taste in pollen? As a first step, learning experiments helped the scientists to establish the bumble bees' preference for certain nutrients—in this case fat and protein.

Fabian Rüdenauer, main author of the study, explained: "We are focusing on fatty and amino acids, which represent the two essential pollen macro nutrients and which are likely to be perceived and thus tasted by bees."

In this context, small amounts of fatty acids were added to pollen to increase its fat content. The researchers found that bumble bees could clearly differentiate between normal pollen and pollen with increased fat content and did show a clear preference for normal pollen. Surprisingly, the bumble bees made no clear distinction when the pollen amino acid content was altered in the same way.

The bumble bee collects pollen from a blue viper's head (Echium vulgare). Credit: Dieter Mahsberg

What is a bumble bee's preferred taste?

Which nutrients actually affect the bumble bees' foraging behavior and what are the consequences for their survival and reproductive capabilities? Those were the central questions guiding the subsequent feeding experiments.

"The more fat the pollen contained, the less the bumble bees consumed that pollen," Leonhardt concluded. Bumble bees actually accepted death over having to consume the high-fat pollen. The work group therefore concluded that fat in pollen adversely affects the bumble bees' reproductive capabilities and survival, which is why it is being avoided.

Similar to the learning experiment, variations in the amino acid content of pollen did not affect the bees' feeding habits, survival or reproduction.

Help for bees and bumble bees

"Our study highlights the importance of fat for foraging bumble bees. It also shows that there is a correlation between nutrient perception, nutritional regulation and reproductive fitness," stated Dr. Johannes Spaethe from the University of Würzburg, who also led the study. "The bees can taste what is good for them and collect their food accordingly," said Leonhardt, summarizing the results.

Currently, the researchers are creating a dataset on pollen nutritional chemistry in order to obtain an overview across the wide spectrum of different plant species. They are also examining the nutritional needs of other species of bees. "In the future, this may lead to better understanding the effect of variation in flowering plant species on bees, and it may improve protective measures such as flower strips in agricultural landscapes," predict the researchers.

Sunflower pollen has medicinal, protective effects on bees

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More information: Fabian A. Ruedenauer et al, Best be(e) on low fat: linking nutrient perception, regulation and fitness, Ecology Letters (2020). DOI: 10.1111/ele.13454

Global cooling after nuclear war would harm ocean life

by Rutgers University

Corals, which are threatened by global climate change and ocean acidification, support a wide range of reef fish at Baker reef in the Pacific Remote Islands. Credit: NOAA Fisheries/Morgan Winston

A nuclear war that cooled Earth could worsen the impact of ocean acidification on corals, clams, oysters and other marine life with shells or skeletons, according to the first study of its kind.

"We found that the ocean's chemistry would change, with global cooling dissolving atmospheric carbon into the upper ocean and exacerbating the primary threat of ocean acidification," said co-author Alan Robock, a Distinguished Professor in the Department of Environmental Sciences in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick.

The study is published in the journal Geophysical Research Letters.

Scientists looked at how climate changes stemming from nuclear war would affect the oceans. They used a global climate model in which the climate reacted to soot (black carbon) in smoke that would be injected into the upper atmosphere from fires ignited by nuclear weapons. They considered a range of hypothetical nuclear wars, including a relatively small one between India and Pakistan and a large one between the United States and Russia.

Excess carbon dioxide from the burning of fossil fuels enters the ocean and reacts with water to form carbonic acid, which decreases ocean pH (makes it more acidic) and lowers levels of carbonate ions. Corals, clams, oysters and other marine organisms use carbonate ions to create their shells and skeletons, according to the National Oceanic and Atmospheric Administration. A more acidic ocean makes it harder to form and maintain shells and skeletons.

The massive amount of smoke from a nuclear conflict would block sunlight and cause global cooling. The cooling would temporarily boost the pH in the surface ocean over five years and briefly lessen the decline in pH from ocean acidification. But the cooling would also lead to lower levels of carbonate ions for about 10 years, challenging shell maintenance in marine organisms.

"We have known for a while that agriculture on land would be severely affected by climate change from nuclear war," Robock said. "A lingering question is whether the survivors could still get food from the sea. Our study is the first step in answering this question."

The next step is to combine projected changes in ocean chemistry with projected changes in temperature and salinity and assess their impacts on shellfish and fish stocks throughout the oceans, he said.

Oysters as catch of the day? Perhaps not, if ocean acidity keeps rising

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More information: Nicole S. Lovenduski et al, The Potential Impact of Nuclear Conflict on Ocean Acidification, Geophysical Research Letters (2020). DOI: 10.1029/2019GL086246

Journal information: Geophysical Research Letters 

ALMA catches beautiful outcome of stellar fight

This new ALMA image shows the outcome of a stellar fight: a complex and stunning gas environment surrounding the binary HD101584. The colours represent speed, going from blue -- gas moving the fastest towards us -- to red -- gas moving the fastest away from us. Jets, almost along the line of sight, propel the material in blue and red. The stars in the binary are located at the single bright dot at the centre of the ring-like structure shown in green, which is moving with the same velocity as the system as a whole along the line of sight. Astronomers believe this ring has its origin in the material ejected as the lower mass star in the binary spiralled towards its red-giant partner. Credit: ALMA (ESO/NAOJ/NRAO), Olofsson et al. Acknowledgement: Robert Cumming

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner, have spotted a peculiar gas cloud that resulted from a confrontation between two stars. One star grew so large it engulfed the other which, in turn, spiralled towards its partner provoking it into shedding its outer layers.

Like humans, stars change with age and ultimately die. For the Sun and stars like it, this change will take it through a phase where, having burned all the hydrogen in its core, it swells up into a large and bright red-giant star. Eventually, the dying Sun will lose its outer layers, leaving behind its core: a hot and dense star called a white dwarf.

"The star system HD101584 is special in the sense that this 'death process' was terminated prematurely and dramatically as a nearby low-mass companion star was engulfed by the giant," said Hans Olofsson of the Chalmers University of Technology, Sweden, who led a recent study, published in Astronomy & Astrophysics, of this intriguing object.

Thanks to new observations with ALMA, complemented by data from the ESO-operated Atacama Pathfinder EXperiment (APEX), Olofsson and his team now know that what happened in the double-star system HD101584 was akin to a stellar fight. As the main star puffed up into a red giant, it grew large enough to swallow its lower-mass partner. In response, the smaller star spiralled in towards the giant's core but didn't collide with it. Rather, this manoeuvre triggered the larger star into an outburst, leaving its gas layers dramatically scattered and its core exposed.

The team says the complex structure of the gas in the HD101584 nebula is due to the smaller star's spiralling towards the red giant, as well as to the jets of gas that formed in this process. As a deadly blow to the already defeated gas layers, these jets blasted through the previously ejected material, forming the rings of gas and the bright bluish and reddish blobs seen in the nebula.

A silver lining of a stellar fight is that it helps astronomers to better understand the final evolution of stars like the Sun. "Currently, we can describe the death processes common to many Sun-like stars, but we cannot explain why or exactly how they happen. HD101584 gives us important clues to solve this puzzle since it is currently in a short transitional phase between better studied evolutionary stages. With detailed images of the environment of HD101584 we can make the connection between the giant star it was before, and the stellar remnant it will soon become," says co-author Sofia Ramstedt from Uppsala University, Sweden.

Co-author Elizabeth Humphreys from ESO in Chile highlighted that ALMA and APEX, located in the country's Atacama region, were crucial to enabling the team to probe "both the physics and chemistry in action" in the gas cloud. She added: "This stunning image of the circumstellar environment of HD101584 would not have been possible without the exquisite sensitivity and angular resolution provided by ALMA."

While current telescopes allow astronomers to study the gas around the binary, the two stars at the centre of the complex nebula are too close together and too far away to be resolved. ESO's Extremely Large Telescope, under construction in Chile's Atacama Desert, "will provide information on the 'heart' of the object," says Olofsson, allowing astronomers a closer look at the fighting pair.

This research was presented in a paper published in Astronomy & Astrophysics. 

Primate venom sheds light on why so many people suffer cat allergies

by University of Queensland FEBRUARY 5, 2020

CC0 bySilke Hahn at de.wikipedia

Research into the toxin of the world's only venomous primate, the slow loris, is shedding light on the potential origins of the allergic qualities of cats.


An international team, led by University of Queensland's Associate Professor Bryan Fry, has been studying slow lorises at the Cikananga Wildlife Rescue Centre in Indonesia.

"Slow lorises are the only known primates with venom and they've been virtually unstudied," Dr. Fry said.

"Despite being a mystery to science, they're commonly smuggled from the wild and sold in the pet trade, so our rescue centre research was the perfect opportunity to do some good in a bad situation.

"Generally slow lorises use their venom to fight with other slow lorises, causing very slow-to-heal wounds.

"But, when humans are bitten, the victim will display symptoms as if they're going into allergic shock."

He said this similarity was even more striking when studied in the lab.

"We analyzed the DNA sequence of the protein in slow loris venom, discovering that it's virtually identical to the allergenic protein on cats.

"Cats secrete and coat themselves with this protein, and that's what you react to if you're allergic to them.

"Our theory is that since this protein is being used as a defensive weapon in slow lorises, it makes sense that cats may be using the allergen as a defensive weapon too.

"The fact that so many people are allergic to cats mightn't be a coincidence.

"This may have been evolutionarily selected for in the wild as a defense against predators.

"This ability to trigger allergy as a weapon mightn't be something restricted to slow lorises, but may have separately evolved in cats at the same time.

"This is a fascinating hypothesis that we are looking to test in future research."

Dr. Fry said the team regarded this as another elegant example of evolution in action.

"This finding shows how inventive nature is when developing new toxic arsenals," he said.

"The human allergy to cats is so prevalent that it would be a remarkable coincidence if this wasn't an evolved defensive weapon, like the same protein used by slow lorises.

"Your pet cat wouldn't know it, but it may have evolved a toxic defense to keep predators as far away from it as possible.

"Similarly, this line of research opens up other fascinating research areas, such as the allergies to ants and bees also being something that has been selected for by evolution—where the victim's immune system is being high-jacked.

"This study is a great example of what makes science so wonderful, where every answer spawns several new and interesting questions."

The research has been published in Toxins.


Explore furtherSlow loris study reveals human rhythm of sleep may be evolutionarily conserved
More information: undefined Scheib et al. The Toxicological Intersection between Allergen and Toxin: A Structural Comparison of the Cat Dander Allergenic Protein Fel d1 and the Slow Loris Brachial Gland Secretion Protein, Toxins (2020). DOI: 10.3390/toxins12020086
Provided by University of Queensland

What the brain really thinks about forever chemicals
by Amy Patterson Neubert, Purdue University FEBRUARY 5, 2020

Forever chemicals are considered a public health issue as adverse health effects have been shown to affect hormones and other aspects of the endocrine system, and some are potentially neurotoxic. But to what extent is unknown, especially for the years and decades they may accumulate in the brain. Credit: Stuart Briers

The human-made chemicals that make our kitchen pans stick-free, our athletic wear water-repellent and firefighting chemicals more efficient do their jobs incredibly well, but it's at the expense of lingering in the body and environment for what is believed to be forever.


These forever chemicals, perfluorooctane sulfonate and perfluorooctanoic acid, more commonly known as PFOS and PFOA, make life easier. But scientists have many questions about these synthetic compounds' long-term effects. They are being used less by consumers, and companies that once championed them are stepping away. But they still have important military and industrial applications, especially in firefighting foams. Even if production completely stopped, the world will still live with them forever.

"These chemicals are detectable in the blood of almost every human. They are often found in other species, as well, including polar bear and whale brains," said Jason Cannon, an associate professor of toxicology at Purdue University. "The carbon-fluorine bond is one of the strongest in nature, and it is difficult to break down, especially when there is more than one fluorine atom on the carbon atom. Most chemicals that we consume or absorb will leave the body in a different chemical form. To the best of our knowledge, these chemicals are not very well metabolized so they bioaccumulate."

These forever chemicals are something that Cannon refers to as a major public health issue as adverse health effects have been shown to affect hormones and other aspects of the endocrine system. Both PFOS and PFOA are per- and polyfluoroalkyl substances, more commonly known as PFAS, and are potentially neurotoxic. But to what extent is unknown, especially for the years and decades they may accumulate in the brain.

"And which regions they accumulate within the brain is unknown," said Cannon, who studies dietary toxins and neurological disease, including gene-environment interactions in Parkinson's disease.

Cannon's recent study published in Toxicological Sciences determined that PFOS is selectively neurotoxic and relevant to specific neurological diseases. In this study, roundworms were exposed to PFOS and PFAS, and it was shown that their dopamine levels and dopamine neurons were highly sensitive and declined. In mammals, dopamine is key to movement, reward and addiction.


"As a Parkinson's disease lab, seeing dopamine level depletions is a hallmark feature of the disease, but starting here, we need to be careful of our interpretation," Cannon said. "Beyond Parkinson's disease, there are a number of dopamine regions in the brain that could be affected and imply neurodegenerative issues or mental health issues. More research is needed."

Cannon's earlier research, published in Toxicology and Applied Pharmacology, took a step toward looking at how dopaminergic function may be affected. This study found that PFOS exposure led to selective decreases of dopamine levels in Northern leopard frogs, a sentinel species. Northern leopard frog larvae were used for testing because their brains feature certain chemical bio features that are more similar to those in humans than those in rodents. This frog species has a breakdown product of dopamine called neuromelanin that binds with toxins.

The three doses evaluated in a laboratory setting reflected high-level amounts from possible military site contaminations. The dopamine decreased significantly in the brains of frogs treated with PFOA at 1,000 parts per billion and PFOS at 100 and 1,000 parts per billion).

"The 1,000 is really pushing it, but the 100, well, there have been some contaminated sites that have been reported to be close to that level," he said. "This is one of the difficulties in conducting toxicology studies; you want environmentally relevant dose but you also are trying model years of exposure over a short time frame. Certainly, the highest dose is probably pretty weak for environmental relevance, but the two lower doses do bear some environmental relevance. We are conducting studies at even lower doses."

These studies on PFAS accumulation in the brain and resultant neurotoxicity were possible thanks to collaborations with labs led by Linda S. Lee, professor of agronomy, and Maria S. Sepúlveda, professor of ecology and natural systems. Cannon also is a member of Purdue's Institute for Integrative Neuroscience and the Center for the Environment, both of which are in Purdue's Discovery Park. He also is a member of the Center for Research on Brain, Behavior and NeuroRehabilitation, CEREBBRAL, in Purdue's College of Health and Human Sciences.

Although many PFOS and PFOAs have been removed, many alternatives with shorter chains are being created.

"It is thought that the shorter chain PFOAs are less toxic," Cannon said. "But I would say we truly don't know that. The data is not there. We have all these alternatives in the environment with little to no toxicity testing. In some cases that may be true. They may metabolize and leave the body faster, but from a neurological standpoint the smaller compounds usually penetrate the brain better. So that is something we need to pay attention too."

Explore furtherPersistent environmental contaminant changes the gut microbiome of mice
More information: Shreesh Raj Sammi et al. Perfluorooctane Sulfonate (PFOS) Produces Dopaminergic Neuropathology in Caenorhabditis elegans, Toxicological Sciences (2019). DOI: 10.1093/toxsci/kfz191

Rachel M. Foguth et al. Developmental exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) selectively decreases brain dopamine levels in Northern leopard frogs, Toxicology and Applied Pharmacology (2019). DOI: 10.1016/j.taap.2019.114623
Journal information: Toxicological Sciences , Toxicology and Applied Pharmacology

Mosaic X-rays reveal Peruvian mummy mysteries

by Debora Van Brenk, University of Western Ontario FEBRUARY 5, 2020

LONG READ 

Undergraduate Anthropology student Lauren Poeta prepares a mummy bundle – called a fardo – of a Peruvian child for X-rays. The Western team has developed scanning processes that better assesses the mummy without damaging the fardo. Credit: Andrew Nelson // Special to Western News

Western researchers, including two undergraduate students, have become pivotal players in developing a mobile X-ray protocol that could transform how mummies are examined in the field.

Anthropology professor Andrew Nelson and his team have pioneered a process to digitize and stitch together X-ray images so that they can non-destructively 'view' Peruvian mummy bundles in their entirety. The process will enable other anthropologists to conduct valuable work without damaging the objects.

"Lots of people have X-rayed mummies. But, as far as I know, we're the first to do the mosaic X-ray technique and do that digitally," Nelson explained.

Mummy bundles—called fardos—sometimes have been examined by unwrapping the textiles encasing the mummy. That process destroys the mummy and its context at least as much as it informs researchers about the past.

A less destructive but more time-consuming examination entails X-raying the bundles using film, which is then developed by hand, then transporting the heavy images home and analyzing them from afar.

But this new process is faster, portable and produces a far more complete picture.

Here's how it works:

Researchers bring a suitcase-sized machine—Nelson's was funded by the Social Sciences and Humanities Research Council of Canada (SSHRC) – originally designed for use by veterinarians. The X-rays then go straight to the computer in digital form. No need to process into film or transport anything off-site. Those two-dimensional images are then electronically stitched together into composite, full-body images for immediate analyses.

Undergraduate Anthropology student David Seston examines digital X-rays of mummy bundles on site in Pachacamec, Peru. Credit: Andrew Nelson // Special to Western News

That scan can stand on its own as a more-than-basic record of the mummy's condition, position and setting. It can also offer rich enough detail for researchers to decide whether the mummy warrants further study through more detailed computer tomography (CT) scanning.

Last summer, Nelson's team conducted 880 X-rays and 31 CT scans in six days at the archaeological site of Pachacamac, Peru, where almost 200 fardos were discovered during excavation for a new museum in 2015.

This is the first time these mummy bundles—which date from about AD 1100 to AD1470—have been examined.

While the X-rays showed many mummies inside the bundles were no longer intact, the scans also indicated many were worthy of further non-destructive investigation.

"The great thing about doing the X-rays digitally and on site was the instant feedback we had," said David Seston, in his final year of undergraduate Anthropology studies and a key member of the team in data management and tech troubleshooting during the six-week study.

Anthropology Ph.D. student Joanna Motley pioneered the composite work in X-ray imaging.

Credit: University of Western Ontario

Lauren Poeta, now in her fourth year of Anthropology, said the fieldwork in Peru—which included both teaching and learning from Peruvian researchers—offered an unparalleled opportunity in experiential learning.

"It was incredible because you don't expect to see that or have the opportunity to do that after just your third year. You get to do the experiential stuff. Instead of seeing pictures in two dimensions or in a textbook, this is totally different. You start to learn what to look for and what's important to see."

Poeta developed a standardized checklist of what researchers should be looking for as they try to discover how the fardos represent a microcosm of their society, including identifying the:

• Wrapping textile;
• Position of the mummy whether extended or with legs flexed towards their chest;
• Person's age, sex and any suspected health issues before death; and
• Type and location of any other artifacts buried with them.

Some fardos that have been CT-scanned and further analyzed show unusual objects wrapped with them.

Decorative shells. Stones. A mysterious folded disc they've nicknamed a 'taco." One person has a sharp object pierced through an eye socket. Another has a tattoo on one hand. One is surrounded by a 'cloud' of cotton seeds, be it to provide filler for the fardo or as a symbol for something else, no one yet knows.

An X-ray composite of a Peruvian mummy bundle showed this skull with an eye socket pierced with a sharp object. A CT scan of the skull of the same Peruvian mummy shows greater detail, including the textiles that were placed around him in death.

Another question as-yet-unanswered is whether mummification—the preservation of tissue and clothing—was the main intent for wrapping and encasing the bodies, or whether mummification was an unintended result of the process, coupled with the dry climate and their burial in sand.

Together, all these details form clues into who these people were as individuals, how they lived, how they interacted with their community and how they were respected in death. They are, Nelson said, individually and collectively important to the study of pre-Columbian life in Peru.

Further study of the fardos and their images continues here year-round and by Peruvian researchers, with further work expected by a Western-Peruvian team this coming summer. "It's the awesome part of having a multi-year project," Nelson said.

A CT scan of the skull of the same Peruvian mummy shows greater detail, including the textiles that were placed around him in death. Credit: University of Western Ontario

Meanwhile, they have co-authored six collaborative papers about their work during and since last summer's research in Peru, and have presented research at archaeological and anthropological proceedings.

For Poeta, the experiential learning offered critical-thinking skills and a greater passion for anthropological fieldwork.

Seston said the experiential learning was both a personal and professional stretch.

Researchers do a preliminary examination of a mummy bundle, one of hundreds discovered in Pachacamec, Peru, during a 2015 excavation to build a new museum. Pictured are, from left, Western student Lauren Poeta, Anthropology professor Andrew Nelson, Arizona researcher Suellen Gauld and archaeologist Sarita Fuentes Villalobos of the Site Museum at Pachacamac. Credit: University of Western Ontario

"As an undergraduate, the chances of getting this kind of opportunity are incredibly rare. I knew when we went down there that this would change my perspective—but I never expected how much.

"A lot of work I do takes place on a computer. But being actually in the field and examining them changes my perspective 100 percent. It's not just an image on a screen. These are people and you have to respect them as people. You honour them by bringing them out and bringing back their stories."

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