Scientists untangle interactions between the Earth's early life forms and the environment over 500 million years

The atmosphere, the ocean and life on Earth interacted over the past 500-plus million years in ways that improved conditions for early organisms to thrive. Now, an interdisciplinary team of scientists has produced a perspective article of this co-evolutionary history published in multidisciplinary open-access journal National Science Review.

"One of our tasks was to summarize the most important discoveries about carbon dioxide and oxygen in the atmosphere and ocean over the past 500 million years," says Syracuse University geochemistry professor Zunli Lu, lead author on the paper. "We reviewed how those physical changes affected the evolution of life in the ocean. But it's a two-way street. The evolution of life also impacted the chemical environment. It is not a trivial task to understand how to build a habitable Earth over long time scales"

The team from Syracuse University, Oxford University and Stanford University explored the intricate feedbacks among ancient life forms, including plants and animals, and the chemical environment in the current Phanerozoic Eon, which began approximately 540 million years ago.

At the start of the Phanerozoic, carbon dioxide levels in the atmosphere were high, and oxygen levels were low. Such a condition would be difficult for many modern organisms to thrive. But ocean algae changed that. They absorbed carbon dioxide from the atmosphere, locked it into organic matter and produced oxygen through photosynthesis.

The ability of animals to live in an ocean environment was affected by oxygen levels. Lu is studying where and when ocean oxygen levels may have risen or fallen during the Phanerozoic using geochemical proxies and model simulations. Co-author Jonathan Payne, professor of Earth and planetary sciences at Stanford University, compares an ancient animal's estimated metabolic requirements to places where it survived or disappeared in the fossil record.

As photosynthetic algae removed atmospheric carbon into sedimentary rocks to lower carbon dioxide and raise oxygen levels, the algae's enzymes became less efficient in fixing carbon. Therefore, algae had to figure out more complicated ways of doing photosynthesis at lower carbon dioxide and higher oxygen levels. It accomplished this by creating internal compartments for photosynthesis with control over the chemistry.

"For algae, it is changes in the environmental ratio of O2/CO2 that seems to be key to driving improved photosynthetic efficiency," says co-author Rosalind Rickaby, who is a professor of geology at Oxford. "What is really intriguing is that these improvements in photosynthetic efficiency may have expanded the chemical envelope of habitability for many forms of life."

Ancient photosynthesizers had to adapt to changes in the physical environment that they themselves had created, notes Lu. "The first part of the history of the Phanerozoic is increasing habitability for life, and then the second part is adaptation."

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Natural GM crops: Grasses take evolutionary shortcut by borrowing genes from their neighbors

Grass may transfer genes from their neighbours in the same way genetically modified crops are made, a new study has revealed.

Research, led by the University of Sheffield, is the first to show the frequency at which grasses incorporate DNA from other species into their genomes through a process known as lateral gene transfer.

The stolen genetic secrets give them an evolutionary advantage by allowing them to grow faster, bigger or stronger and adapt to new environments quicker.

Understanding the rate is important to know the potential impact it can have on a plant's evolution and how it adapts to the environment.

Grasses are the most ecologically and economically important group of plants, covering 30% of the earth's terrestrial surface and producing a majority of our food.

The Sheffield team sequenced multiple genomes of a species of tropical grass and determined at different time points in its evolution how many genes were acquired -- giving a rate of accumulation.

It is now thought these transfers are likely to occur in the same way that some genetically modified crops are made.

These findings, published in the journal New Phytologist could inform future work to harness the process to improve crop productivity and make more resilient crops, and have implications on how we view and use controversial GM crops.

Dr. Luke Dunning, Research Fellow from the University of Sheffield's School of Biosciences, and senior author of the research, said: "There are many methods to make GM crops, some which require substantial human intervention and some that don't. Some of these methods that require minimal human intervention could occur naturally and facilitate the transfers we have observed in wild grasses.

"These methods work by contaminating the reproductive process with DNA from a third individual. Our current working hypothesis, and something we plan to test in the near future, is that these same methods are responsible for the gene transfers we document in wild grasses.

"This means, in the near future, controversial genetic modification could be perceived as more of a natural process.

"Currently, these 'natural' reproductive contamination methods are not as efficient in producing GM plants as those that are used routinely, but by further understanding how lateral gene transfer occurs in the wild we may be able to increase the success of this process."

Since Darwin, much of our understanding of evolution has been based on the assumption that genetic information is passed from parents to offspring -- the rule of common descent for plant and animal evolution.

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Heredity and environment account for people's love of nature

Humans have a positive view of nature. But is this due to an approach we have learned while growing up, or is it something we are born with? The answer is 'Both', according to researchers at the University of Gothenburg and the Swedish University of Agricultural Sciences. Our love of nature is highly individual and should influence how we plan our cities, say the researchers.

It is well known that nature has a positive effect on people. In cities in particular, studies have shown that trees and other greenery contribute to people's wellbeing. However, experts do not agree on the reasons behind this phenomenon, known as biophilia.

Some believe that it is natural for humans to feel an automatic positive attachment because human development has occurred in nature. Others argue that there is no evidence for this, and that influences during our childhood determine how we view nature.

A wide range of factors involved

Researchers from the University of Gothenburg and the Swedish University of Agricultural Sciences (SLU) have reviewed several studies within this field that examine both innate factors and what individuals experience during their lives, primarily as children. In a new scientific article, the researchers conclude that both heredity and environment influence an individual's attitude to nature, but that a wide range of factors also influence how love of nature is expressed.

"We have been able to establish that many people have an unconscious positive experience of nature," says Bengt Gunnarsson, Professor Emeritus of Environmental Science at the University of Gothenburg. "But the biophilia hypothesis should be modified to link the variation in individuals' relationships with nature to an interaction between heredity and environmental influence."

Nature mean different things

This is because people react differently to nature. In a Japanese study, subjects were asked to walk in a forest and in a city while their heartbeat was measured. This showed that positive emotions while walking in a forest increased in 65% of people. Thus, far from everyone had a positive perception of nature. Another environmental psychology study found that research subjects are unconsciously drawn to nature instead of cities, and that this attraction was reinforced in those whose childhood was rich in nature.

"An additional study on identical and non-identical twins showed that a genetic component influences an individual's positive or negative relationship with nature," continues Bengt. "But the study also highlighted the importance of environment in terms of attitudes towards nature."

Moreover, nature can mean completely different things to different people. Some enjoy parks with lawns and planted trees, while others prefer being in the wilderness. The researchers believe that this variation is also determined by both heredity and environment.

"So it's important that we don't standardise nature when planning greenery in our towns and cities," adds Marcus Hedblom, a researcher at SLU and co-author of the article. "We shouldn't replace wild greenery with a park and assume that it will be good for everyone."

Urban nature brings many benefits

In today's urban planning, densification has been a common way to achieve a more sustainable city. This can sometimes come into conflict with efforts to offer nature in cities. A large number of studies suggest that urban parks and green spaces contribute to increased physical activity and recovery from stress. The greenery in our cities is also important in other respects. Trees can clean the air and provide shade to create a tolerable urban climate on hot days.

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'Time-traveling' pathogens in melting permafrost pose likely risk to environment

Ancient pathogens that escape from melting permafrost have real potential to damage microbial communities and might potentially threaten human health, according to a new study by Giovanni Strona of the European Commission Joint Research Centre and colleagues, published July 27 in the open-access journal PLOS Computational Biology.

The idea that "time-traveling" pathogens trapped in ice or hidden in remote laboratory facilities could break free to cause catastrophic outbreaks has inspired generations of novelists and screenwriters. While melting glaciers and permafrost are giving many types of dormant microbes the opportunity to re-emerge, the potential threats to human health and the environment posed by these microbes have been difficult to estimate.

In a new study, Strona's team quantified the ecological risks posed by these microbes using computer simulations. The researchers performed artificial evolution experiments where digital virus-like pathogens from the past invade communities of bacteria-like hosts. They compared the effects of invading pathogens on the diversity of host bacteria to diversity in control communities where no invasion occurred.

The team found that in their simulations, the ancient invading pathogens could often survive and evolve in the modern community, and about 3 percent became dominant. While most of the dominant invaders had little effect on the composition of the larger community, about 1 percent of the invaders yielded unpredictable results. Some caused up to one third of the host species to die out, while others increased diversity by up to 12 percent compared to the control simulations.

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Automated analysis of microplastic concentrations

How high are concentrations of microplastics in the environment, in our drinking water or in foods? Researchers at the Technical University of Munich (TUM) have developed an automated analysis method for the identification and quantification of particles.

Microplastics are everywhere in the environment. The tiny particles, with diameters of less than 5 millimeters, can also absorb and transport contaminants and toxins. “We urgently need analytical techniques to learn about the size, concentration and composition of these particles,” says Dr. Natalia Ivleva at the Chair of Analytical Chemistry and Water Chemistry at TUM. Together with her team, the scientist has developed a new process.

To be able to detect microplastic particles, the researchers had several hurdles to overcome: The first was the problem of low concentrations. River water, for example, contains massive amounts of suspended solids and fine sand, with plastic accounting for less than 1 percent of the particles. These particles must first be isolated before their concentrations and ultimately their chemical composition are determined. Previous methods have relied on the analysis of the residues that are released when the samples are heated. With that approach, however, it is not possible to determine the number, size and shape of the plastic particles.

Plastics can be identified through light scattering

“Our approach is fundamentally different,” says Dr. Ivleva: “It is particle-based. That means that instead of destroying the particles, we analyze them directly.” To do this, the researchers use a method known as Raman microspectroscopy. It works by shining a monochromatic laser source onto a sample and detecting the light scattered by the molecules. Comparing the scattered light against the laser source provides information on the substance under investigation. To analyze plastic particles with a diameter greater than 1 µm (micrometer), they must first be filtered out of the aqueous solution, detected under the microscope and then illuminated with laser light. Because plastics such as polyethylene, polystyrene and polyvinyl chloride scatter the photons in characteristic ways, they each generate signals as unique as a fingerprint.

Automation instead of manual measurements

It took years to develop the tracing process: “When we started, we still had to make manual measurements,” recalls the chemist. “It took us months to investigate a few thousand particles.” In the meantime the team has succeeded in automating the detection of microplastics. A single analysis no longer takes weeks, but only a matter of hours. Although the tiny particles still have to be filtered out of the aqueous solution, followed by placement of the filter under the Raman microspectroscope, all remaining steps are carried out by the software developed by the team. The plastic particles are first localized with a light microscope, photographed and measured, and the particles are distinguished from fibers. The software uses these data to compute the number of particles and fibers and to select the image sections needed for a statistically significant result in the subsequent Raman spectroscopy.

In the next step, the laser is directed onto the sample and the scattering is detected and analyzed. This allows quick and reliable analysis of the number, size, shape and composition of the microplastics. The open-source TUM-Particle Typer 2 software is now available to researchers around the world.

Nanoplastics require special detection processes

To investigate nanoparticles with diameters of less than 1 µm, however, Dr. Ivleva’s team is already working on a modified process. “Nanoparticles like these are difficult or even impossible to discern under a light microscope. To detect them, we first have to carry out size fractionation and then identify them,” explains the researcher.

For this purpose, a field flow fractionation (FFF) system is used. This creates a water flow that captures the particles – depending on their size – and separates them by transporting them at varying speeds. A specially developed device, combined with Raman spectroscopy, permits the chemical characterization of different types of nanoplastics.

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Our favorite vintages and their precarious mountainside homes are at risk due to climate change, environmental scientists warn

Tucked into the hillsides of Italy, Portugal, and Spain, some of the world's most famous -- and most difficult to maintain -- vineyards are heralded for their unique flavor profiles and centuries of tradition. But as extreme weather and changing socioeconomic conditions make this so-called "heroic viticulture" even more challenging, scientists worry these grapes and their cultural histories are at risk. In a Backstory publishing on July 14 in the journal iScience, researchers argue that farmers and scientists must work together to protect some of the world's most celebrated wines.

"The risk is not only losing an agricultural product or seeing a landscape change, negatively impacting the local economy," write the authors from the University of Padova. "The risk is losing entire communities' history and their cultural roots."

Vineyards are considered "heroic viticulture" sites if they have a slope steeper than 30 percent, are located on small islands or at an altitude higher than 500 meters above sea level, or if they incorporate vines grown on terraces. The name "heroic" originated from the inherent difficulty of cultivating and harvesting crops in these landscapes. Some of the most famous, centuries-old examples of heroic viticulture include the Prosecco Hills of Conegliano and Valdobbiadene and the traditional vineyards of Pantelleria Island, both of which are protected by UNESCO.

"The great effort required to manage these areas reinforces the specific human-environment connection," write the authors. "This is why they are recognized as cultural uniquenesses of primary historical and social importance, where traditional knowledge is still the determining element."

In the Backstory, the authors list soil degradation and drought as the biggest climate change-related risks to heroic viticulture. They also argue that the vineyards face several significant socioeconomic barriers.

"The last half past century has been characterized by rural exodus and a gradual abandonment of mountain landscapes," the authors write. "The new generation is unwilling to continue working under extreme conditions if economic benefits are insignificant."

In order to protect heroic viticulture sites, the authors suggest several forms of potential solutions, from strategic communications designed to unite scientists, farmers, and consumers to onsite solutions like small water storage systems integrated into the vineyard landscapes that prevent runoff and retain water for future usage. They also underline the importance of education, including "educating the new generation about the benefits of rural reality, the need to preserve cultural heritage, live in equilibrium with the environment, and to have a sustainable approach to agriculture."

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Human-made materials in nests can bring both risks and benefit for birds

We all discard a huge amount of plastic and other human-made materials into the environment, and these are often picked up by birds. New research has shown that 176 bird species around the world are now known to include a wide range of anthropogenic materials in their nests. All over the world, birds are using our left-over or discarded materials. Seabirds in Australia incorporate fishing nets into their nests, ospreys in North America include baler twine, birds living in cities in South America add cigarette butts, and common blackbirds in Europe pick up plastic bags to add to their nests.

This material found in birds' nests can be beneficial say researchers. For example, cigarette butts retain nicotine and other compounds that repel ectoparasites that attach themselves to nestling bird's skin and suck blood from them. Meanwhile, there are suggestions that harder human-made materials may help to provide structural support for birds' nests, while plastic films could help provide insulation and keep offspring warm. Despite such potential benefits, it is important to remember that such anthropogenic material can also be harmful to birds.

This research was published in a special issue of the Philosophical Transactions of the Royal Society B on "The evolutionary ecology of nests: a cross-taxon approach." The special issue was jointly organised by Mark Mainwaring, a Lecturer in Global Change Biology in the School of Natural Sciences at Bangor University.

Mark Mainwaring said, "The special issue highlights that the nests of a wide range of taxa -- from birds to mammals to fish to reptiles -- allow them to adapt to human-induced pressures. Those pressures range from the inclusion of anthropogenic materials into their nests through to providing parents and offspring with a place to protect themselves from increasingly hot temperatures in a changing climate."

Anthropogenic materials sometimes harm birds. Parents and offspring sometimes become fatally entangled in baler twine. Meanwhile, offspring sometimes ingest anthropogenic material after mistaking it for natural prey items. Finally, the inclusion of colourful anthropogenic materials into nests attracts predators to those nests who then prey upon the eggs or nestlings. This means that we need to reduce the amount of plastic and other anthropogenic material that we discard.

The lead author of the study, Zuzanna Jagiełło who is based at the Poznań University of Life Sciences in Poland, added, "A wide variety of bird species included anthropogenic materials into their nests. This is worrying because it is becoming increasingly apparent that such materials can harm nestlings and even adult birds."

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The other side of the story: How evolution impacts the environment

The story of the peppered moths is a textbook evolutionary tale. As coal smoke darkened tree bark near England's cities during the Industrial Revolution, white-bodied peppered moths became conspicuous targets for predators and their numbers quickly dwindled. Meanwhile, black-bodied moths, which had been rare, thrived and became dominant in their newly darkened environment.

The peppered moths became a classic example of how environmental change drives species evolution. But in recent years, scientists have begun thinking about the inverse process. Might there be a feedback loop in which species evolution drives ecological change? Now, a new study by researchers at the University of Rhode Island shows some of the best evidence yet for that very phenomenon.

In research published in the Proceedings of the National Academy of Sciences, the researchers show that an evolutionary change in the length of lizards' legs can have a significant impact on vegetation growth and spider populations on small islands in the Bahamas. This is one of the first times, the researchers say, that such dramatic evolution-to-environment effects have been documented in a natural setting.

"The idea here is that, in addition to the environment shaping the traits of organisms through evolution, those trait changes should feed back and drive changes in predator-prey relationships and other ecological interactions between species," said Jason Kolbe, a professor of biological sciences at the University of Rhode Island and one of the study's senior authors. "And we really need to understand how those dynamics work so we can make predictions about how populations are going to persist, and what sort of ecological changes might result."

For the last 20 years, Kolbe and his colleagues have been observing the evolutionary dynamics of anole lizard populations on a chain of tiny islands in the Bahamas. The chain is made up of around 40 islands ranging from a few dozen to a few hundred meters in area -- small enough that the researchers can keep close tabs on the lizards living there. And the islands are far enough apart that lizards can't easily hop from one island to another, so distinct populations can be isolated from each other.

Previous research had shown that brown anoles adapt quickly to the characteristics of surrounding vegetation. In habitats where the diameter of brush and tree limbs is smaller, natural selection favors lizards with shorter legs, which enable individuals to move more quickly when escaping predators or chasing a snack. In contrast, lankier lizards tend to fare better where the tree and plant limbs are thicker. Researchers have shown that this limb length trait can evolve quickly in brown anoles -- in just a few generations.

For this new study, Kolbe and his team wanted to see how this evolved limb-length trait might affect the ecosystems on the tiny Bahamian islands. The idea was to separate short- and long-legged lizards on islands of their own, then look for differences in how the lizard populations affect the ecology of their island homes.

Armed with specialized lizard wrangling gear -- poles with tiny lassos made of dental floss at the end -- the team captured hundreds of brown anoles. They then measured the leg length of each lizard, keeping the ones whose limbs were either especially long or especially short and returning the rest to the wild. Once they had distinct populations of short- and long-limbed lizards, they set each population free on islands that previously had no lizards living on them.

Since the experimental islands were mostly covered by smaller diameter vegetation, the researchers expected that the short-legged lizards would be better adapted to that environment, that is, more maneuverable and better able to catch prey in the trees and brush. The question the researchers wanted to answer was whether the ecological effects of those highly effective hunters could be detected.

After eight months, the researchers checked back on the islands to look for ecological differences between islands stocked with the short- and long-legged groups. The differences, it turned out, were substantial. On islands with shorter-legged lizards, populations of web spiders -- a key prey item for brown anoles -- were reduced by 41% compared to islands with lanky lizards. There were significant differences in plant growth as well. Because the short-legged lizards were better at preying on insect herbivores, plants flourished. On islands with short-legged lizards, buttonwood trees had twice as much shoot growth compared to trees on islands with long-legged lizards, the researchers found.

The results, Kolbe says, help to bring the interaction between ecology and evolution full circle.

"These findings help us to close that feedback loop," Kolbe said. "We knew from previous research that ecological factors shape limb length, and now we show the reciprocal relationship of that evolutionary change on the environment."

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An X-ray look at the heart of powerful quasars

Researchers have observed the X-ray emission of the most luminous quasar seen in the last 9 billion years of cosmic history, known as SMSS J114447.77-430859.3, or J1144 for short. The new perspective sheds light on the inner workings of quasars and how they interact with their environment. The research is published in Monthly Notices of the Royal Astronomical Society.

Hosted by a galaxy 9.6 billion light years away from the Earth, between the constellations of Centaurus and Hydra, J1144 is extremely powerful, shining 100,000 billion times brighter than the Sun. J1144 is much closer to Earth than other sources of the same luminosity, allowing astronomers to gain insight into the black hole powering the quasar and its surrounding environment. The study was led by Dr Elias Kammoun, a postdoctoral researcher at the Research Institute in Astrophysics and Planetology (IRAP), and Zsofi Igo, a PhD candidate at the Max Planck Institute for Extraterrestrial Physics (MPE).

Quasars are among the brightest and most distant objects in the known universe, powered by the fall of gas into a supermassive black hole. They can be described as active galactic nuclei (AGN) of very high luminosity that emit vast amounts of electromagnetic radiation observable in radio, infrared, visible, ultraviolet and X-ray wavelengths. J1144 was initially observed in visible wavelengths in 2022 by the SkyMapper Southern Survey (SMSS).

For this study, researchers combined observations from several space-based observatories: the eROSITA instrument on board the Spectrum-Roentgen-Gamma (SRG) observatory, the ESA XMM-Newton observatory, NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), and NASA's Neil Gehrels Swift observatory.

The team used the data from the four observatories to measure the temperature of the X-rays being emitted from the quasar. They found this temperature to be around 350 million Kelvin, more than 60,000 times the temperature at the surface of the Sun. The team also found that the mass of the black hole at the quasar's centre is around 10 billion times the mass of the Sun, and the rate at which it is growing to be of the order of 100 solar masses per year.

The X-ray light from this source varied on a time scale of a few days, which is not usually seen in quasars with black holes as large as the one residing in J1144. The typical timescale of variability for a black hole of this size would be on the order of months or even years. The observations also showed that while a portion of the gas is swallowed by the black hole, some gas is ejected in the form of extremely powerful winds, injecting large amounts of energy into the host galaxy.

Dr. Kammoun, lead author of the paper, says "We were very surprised that no prior X-ray observatory has ever observed this source despite its extreme power."

He adds, "Similar quasars are usually found at much larger distances, so they appear much fainter, and we see them as they were when the Universe was only 2-3 billion years old. J1144 is a very rare source as it is so luminous and much closer to Earth (although still at a huge distance!), giving us a unique glimpse of what such powerful quasars look like."

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Vanishing glaciers threaten alpine biodiversity

With glaciers melting at unprecedented rates due to climate change, invertebrates that live in the cold meltwater rivers of the European Alps will face widespread habitat loss, warn researchers.

Many of the species are likely to become restricted to cold habitats that will only persist higher in the mountains, and these areas are also likely to see pressures from the skiing and tourism industries or from the development of hydroelectric plants.

The research study -- led jointly by the University of Leeds and University of Essex -- calls on conservationists to consider new measures to protect aquatic biodiversity.

Invertebrates -- key role in ecosystems

The invertebrates, which include stoneflies, midges and flatworms, play a key role in nutrient cycling and organic matter transfer to fish, amphibians, birds and mammals in the wider Alpine ecosystem.

Using glacier, landscape and biodiversity mapping data collected across the Alps, scientists from across Europe simulated how key invertebrate populations across the mountain range are likely to change between now and 2100 because of climate change.

As the climate warms, the modelling predicted the invertebrate species would seek out colder conditions in the highest parts of the mountain range. In the future, these colder areas are also likely to be prioritised for skiing or tourism or the development of hydropower plants.

Lee Brown, Professor of Aquatic Science at the University of Leeds who co-led the research, said: "Conservationists need to be thinking about how protected area designations must evolve to take into account the effects of climate change.

"It may be that some species will have to be moved to refuge areas if we want to safeguard their survival as many of them are not strong fliers so they cannot disperse easily through the mountains."

Alpine climate is changing rapidly

The research, involving a collaboration between nine European research institutions, brought together data on invertebrate species distribution in the Alps, an area that covers more than 34,000 square kilometres, and mapped it alongside expected changes to glaciers and river flows.

There was sufficient data to model what was likely to happen to 19 invertebrate species, mainly aquatic insects, that live in the cold-water regions of the Alps.

Dr Jonathan Carrivick, from the School of Geography at Leeds who co-led the research, said: "We have quantified that as glaciers melt and retreat, the rivers running through the Alps will experience major changes in their water source contributions.

"In the short term, some will carry more water and some new tributary rivers will form, but over several decades from now -- most rivers will become drier, flow slower and become more stable, and there could even have periods in a year when there is no water flow. Additionally, most water in Alpine rivers will also be warmer in the future."

Losers and winners

By the turn of the century, the modelling predicts that most of the species would have experienced "consistent losses" of habitat.

Those hardest hit are expected to be the non-biting midges, Diamesa latitarsis grp., D. steinboecki, and D. bertrami; the stonefly, Rhabdiopteryx alpina; and mayfly, Rhithrogena nivata.

However, several species are expected to benefit from the habitat changes, including the flatworm, Crenobia alpina and the flat headed may fly, Rhithrogena loyolaea.

Other species would find refuge in new locations. The scientists predict the stonefly Dictyogenus alpinus and the caddisfly Drusus discolor will be able to survive in the Rhone valley in southeast France while other species will be lost from the rivers that flow into the Danube basin.

Conservation

Writing in the paper, the researchers describe the "substantial work" that is necessary to protect the biodiversity in rivers that are being fed by retreating glaciers. The locations where glaciers still exist late in the 21st century are likely to be prioritised for hydropower dam construction and ski resort development.

Dr Martin Wilkes, from the University of Essex and who co-led the research, said: "The losses we predict for Alpine biodiversity by the end of this century relate to just one of several possible climate change scenarios.

"Decisive action by world leaders to reduce greenhouse gas emissions could limit the losses. On the other hand, inaction could mean that the losses happen sooner than we predict."

Understanding how invertebrate populations respond to climate changes is key to understanding how biodiversity in high mountainous areas can be affected, and the techniques developed in the study could be applied to other mountain environments.

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How the brain's 'internal compass' works

Scientists have gained new insights into the part of the brain that gives us a sense of direction, by tracking neural activity with the latest advances in brain imaging techniques. The findings shed light on how the brain orients itself in changing environments -- and even the processes that can go wrong with degenerative diseases like dementia, that leave people feeling lost and confused.

"Neuroscience research has witnessed a technology revolution in the last decade allowing us to ask and answer questions that could only be dreamed of just years ago," says Mark Brandon, an Associate Professor of psychiatry at McGill University and researcher at the Douglas Research Centre, who co-led the research with Zaki Ajabi, a former student at McGill University and now a postdoctoral research fellow at Harvard University.

Reading the brain's internal compass

To understand how visual information impacts the brain's internal compass, the researchers exposed mice to a disorienting virtual world while recording the brain's neural activity. The team recorded the brain's internal compass with unprecedented precision using the latest advances in neuronal recording technology.

This ability to accurately decode the animal's internal head direction allowed the researchers to explore how the Head-Direction cells, which make up the brain's internal compass, support the brain's ability to re-orient itself in changing surroundings. Specifically, the research team identified a phenomenon they term 'network gain' that allowed the brain's internal compass to reorient after the mice were disoriented. "It's as if the brain has a mechanism to implement a 'reset button' allowing for rapid reorientation of its internal compass in confusing situations," says Ajabi.

Although the animals in this study were exposed to unnatural visual experiences, the authors argue that such scenarios are already relevant to the modern human experience, especially with the rapid spread of virtual reality technology. These findings "may eventually explain how virtual reality systems can easily take control over our sense of orientation," adds Ajabi.

The results inspired the research team to develop new models to better understand the underlying mechanisms. "This work is a beautiful example of how experimental and computational approaches together can advance our understanding of brain activity that drives behaviour," says co-author Xue-Xin Wei, a computational neuroscientist and an Assistant Professor at The University of Texas at Austin.

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What 'Chornobyl dogs' can tell us about survival in contaminated environments

In the first step toward understanding how dogs -- and perhaps humans -- might adapt to intense environmental pressures such as exposure to radiation, heavy metals, or toxic chemicals, researchers atNorth Carolina State, Columbia University Mailman School of Public Health, University of South Carolina, and the National Institutes of Healthfound thattwo groups of dogs living within the Chornobyl Exclusion Zone, one at the site of the former Chornobyl reactors, and another 16.5 km away in Chornobyl City, showed significant genetic differences between them. The results indicate that these are two distinct populations that rarely interbreed. While earlier studiesfocused on the effects of the Chornobyl Nuclear Power Plant disaster on various species of wildlife, this is the firstinvestigation into the genetic structure of stray dogs living near the Chornobyl nuclear power plant.

The 1986 Chornobyl nuclear power plant disaster displaced more than 300,000 people living nearby and led to the establishment of an Exclusion Zone, a "no man's land" of an approximately 30 km radius surrounding the damaged reactor complex, While a massive steam explosion releasing enormous amounts of ionizing radiation into the air, water, and soil was the direct cause of the catastrophe, radiation exposure is not the only environmental hazard resulting from the disaster. Chemicals, toxic metals, pesticides, and organic compounds left behind by years-long cleanup efforts and from abandoned and decaying structures, including the nearby abandoned city of Pripyat and the Duga-1 military base, all contribute to an ecological and environmental disaster.

"Somehow, two small populations of dogs managed to survive in that highly toxic environment," noted Norman J. Kleiman, PhD, assistant professor of Environmental Health Sciences at Columbia Mailman School of Public Health, and a co-author. "In addition to classifying the population dynamics within these dogs at both locations, we took the first steps towards understanding how chronic exposure to multiple environmental hazards may have impacted these populations."

"The overarching question here is: does an environmental disaster of this magnitude have a genetic impact on life in the region?" says Matthew Breen, Oscar J. Fletcher Distinguished Professor of Comparative Oncology Genetics at NC State, and a corresponding author. "And we have two populations of dogs living at and near the site of a major environmental disaster that may provide key information to help us answer that question."

Earlier research by the co-authors, led by collaborators at NIH, used a much smaller set of genetic variants, but a larger number of dogs, to show that the two populations were separate and that each had complicated family structures.

In this parallel study, the team analyzed the dog DNA samples with four times the number of genetic variants, which provided a closer look at the genomes. In addition to confirming that the two populations are indeed genetically distinct, the team were also able to identify 391 outlier regions in the genomes of the dogs that differed between dogs living at the two locations. "Think of these regions as markers, or signposts, on a highway," Breen says. "They identify areas within the genome where we should look more closely at nearby genes. Moreover, some of these markers are pointing to genes associated with genetic repair; specifically, with genetic repair after exposures similar to those experienced by the dogs in Chornobyl." He went on to say "at this stage we cannot say for sure that any genetic alterations are in response to the multigenerational and complex exposures; we have a lot more work to do to determine if that is the case"

"The question we must answer now are why are there striking genetic differences between the two dog populations?" says Megan Dillion, PhD candidate at NC State and a lead author of the published study. "Are the differences just due to genetic drift, or are they due to the unique environmental stressors at each location?"

"The dog is a sentinel species," Breen says. "By and teasing out whether or not the genetic changes we detected in these dogs are the canine genome's response to the exposures the populations have faced, we may be able to understand how the dogs survived in such a hostile environment and what that might mean for any population -- animal or human -- that experiences similar exposures."

"Though 37 years have passed since the accident, the ~30-year-long half-lives of lingering radioisotopes means the danger posed by radiation exposure is still very much real," notes Kleiman, who is also director of the Columbia University Radiation Safety Officer Training course. "When radiation exposure is combined with a complex toxic chemical mixture of uncertain composition, there are very real human health concerns raised for the thousands of people who continue to work within the Exclusion Zone on continuing cleanup efforts as well as at two newly constructed nuclear fuel reprocessing plants."

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Waxing and waning of environment influences hominin dispersals across ancient Iran

A world-first model of paleoclimate and hydrology in Iran has highlighted favourable routes for Neanderthals and modern human expansions eastwards into Asia.

Published in PLOS ONE, the findings reveal for the first time that multiple humid periods in ancient Iran led to the expansions of human populations, opening dispersal route across the region, and the possible interactions of species such as Neanderthals and our own Homo sapiens.

Professor Michael Petraglia, a key researcher in the study, said historic humid periods resulted in massive changes to ecosystems and led the team to identify large lakes in areas that were formerly deserts.

"Conversely, during glacial periods this increased aridity would have led to the expansion of deserts, led to contractions, and the isolation of hominin populations," said Professor Petraglia, who is the Director of Griffith's Australian Research Centre for Human Evolution.

"This cycle of wetting and drying is shown for the first time in Iran."

The research team, led by PhD candidate Mohammad Javad Shoaee from the Max Planck Institute for Geoanthropology in Germany, found that during Marine Isotope Stage (MIS) 5, a warm, humid period beginning roughly 130,000 years ago, lakes and rivers enabled two pathways for human groups.

One was a northern route through the Alborz and Kopet Dagh Mountains and north of the Dasht-I Kavir desert. The other route, first identified here, ran south along the Zagros Mountains before extending eastwards towards Pakistan and Afghanistan.

The researchers also found evidence for a potential northern route during MIS 3, beginning about 57,000 years ago, which, given artifacts attributed to multiple tool making groups, could have permitted interactions between modern humans and Neanderthals.

"These findings highlight the importance of Iran for our species' dispersals out of Africa and ultimately around the globe," said Professor Petraglia.

"As in other regions long considered too arid for early human occupations, such as the Arabian Peninsula, recent palaeoclimatic research is changing how we understand the human story and the role that changing climates have played."

"We recognised a new southern route along the Zagros Mountains and extending eastwards towards Pakistan and Afghanistan. We found evidence for a potential northern route during MIS 3, which would have permitted hominin movements and species interactions in Southwest Asia," Shoaee said.

To find out how human groups made their way into Iran, the team developed the first spatially comprehensive, high resolution palaeohydrological model for Iran.

They then compared their model, which showed when and where water was available, to the distribution of previously documented archaeological sites.

The result was a clear relationship between the availability of water and the evidence of human presence.

Not only does the current study help to explain the presence of previously documented sites, it also serves as a guide for future archaeological surveys in the region.

"Our paleohydrological analyses identified 145,354km of rivers and 115 paleolakes calculated from 6380 paleolake deposits. Only a handful of these paleolakes have so far been studied," Shoaee said.

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Oldest spinosaur brains revealed

Researchers from the University of Southampton and Ohio University have reconstructed the brains and inner ears of two British spinosaurs, helping uncover how these large predatory dinosaurs interacted with their environment.

Spinosaurs are an unusual group of theropod dinosaurs, equipped with long, crocodile-like jaws and conical teeth. These adaptations helped them live a somewhat-aquatic lifestyle that involved stalking riverbanks in quest of prey, among which were large fish. This way of life was very different from that of more familiar theropods, like Allosaurus and Tyrannosaurus.

To better understand the evolution of spinosaur brains and senses, the team scanned fossils of Baryonyx from Surrey and Ceratosuchops from the Isle of Wight. These two are the oldest spinosaurs for which braincase material is known. The huge creatures would have been roaming the planet about 125 million years ago years ago. The braincases of both specimens are well preserved, and the team digitally reconstructed the internal soft tissues that had long rotted away.

The researchers found the olfactory bulbs, which process smells, weren't particularly developed, and the ear was probably attuned to low frequency sounds. Those parts of the brain involved in keeping the head stable and the gaze fixed on prey were possibly less developed than they were in later, more specialised spinosaurs.

Findings are due to be published in the Journal of Anatomy.

"Despite their unusual ecology, it seems the brains and senses of these early spinosaurs retained many aspects in common with other large-bodied theropods -- there is no evidence that their semi-aquatic lifestyles are reflected in the way their brains are organised," said University of Southampton PhD student Chris Barker, who led the study.

One interpretation of this evidence is that the theropod ancestors of spinosaurs already possessed brains and sensory adaptations suited for part-time fish catching, and that 'all' spinosaurs needed to do to become specialised for a semi-aquatic existence was evolve an unusual snout and teeth.

"Because the skulls of all spinosaurs are so specialised for fish-catching, it's surprising to see such 'non-specialised' brains," said contributing author Dr Darren Naish. "But the results are still significant. It's exciting to get so much information on sensory abilities -- on hearing, sense of smell, balance and so on -- from British dinosaurs. Using cutting-edged technology, we basically obtained all the brain-related information we possibly could from these fossils," Dr Naish said.

Over the last few years, the EvoPalaeo Lab at the University of Southampton has conducted substantial research on new spinosaurs from the Isle of Wight. Ceratosuchops itself was only announced by the team in 2021, and its discovery was followed up by the publication of another new spinosaur -- the gigantic White Rock spinosaur -- in 2022. The braincase of Ceratosuchops was scanned at the ?-Vis X-ray Imaging Centre at the University of Southampton, home to some of the most powerful CT scanners in the country, and a model of its brain will be on display alongside its bones at Dinosaur Isle Museum in Sandown, on the Isle of Wight.

"This new research is just the latest in what amounts to a revolution in palaeontology due to advances in CT-based imaging of fossils," said co-author Lawrence M. Witmer, professor of anatomy at the Ohio University Heritage College of Osteopathic Medicine, who has been CT scanning dinosaurs -- including Baryonyx -- for over 25 years. "We're now in a position to be able to assess the cognitive and sensory capabilities of extinct animals and explore how the brain evolved in behaviourally extreme dinosaurs like spinosaurs."

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Light from outside our galaxy brighter than expected

Scientists analyzed new measurements showing that the light emitted by stars outside our galaxy is two to three times brighter than the light from known populations of galaxies, challenging assumptions about the number and environment of stars are in the universe. Results of the study led by researchers at Rochester Institute of Technology have been posted to ArXiv and accepted for publication in The Astrophysical Journal.

The research team analyzed hundreds of images of background light taken by the Long-Range Reconnaissance Imager (LORRI) on NASA's New Horizons mission to calculate the cosmic optical background (COB) -- the sum of light emitted by stars beyond the Milky Way over the history of the universe. If the COB brightness doesn't equal the light from galaxies we know about, it suggests there might be missing sources of optical light in the universe.

"We see more light than we should see based on the populations of galaxies that we understand to exist and how much light we estimate they should produce," said Teresa Symons '22 Ph.D. (astrophysical sciences and technology), who led the study for her dissertation and is now a postdoctoral researcher at University of California Irvine. "Determining what is producing that light could change our fundamental understanding of how the universe formed over time."

Earlier this year, an independent team of scientists reported the COB was twice as large as originally believed in Astrophysical Journal Letters. Those results were no fluke, as corroborated using a much broader set of LORRI observations in the new study by Symons, RIT Associate Professor Michael Zemcov, and researchers at the Jet Propulsion Laboratory at Caltech, UC Irvine, UC Berkeley, and Johns Hopkins University.

While an unobscured measurement of the COB is difficult to achieve from the Earth due to dust between planets, the New Horizons spacecraft is at the edge of our solar system where this foreground is minimal and provides a much clearer view for this type of study. The scientists hope that future missions and instruments can be developed to help explore the discrepancy.

"This has gotten to the point where it's an actual mystery that needs to be solved," said Zemcov, a research professor at RIT's Center for Detectors and School of Physics and Astronomy. "I hope that some of the experiments we're involved in here at RIT including CIBER-2 and SPHEREx can help us resolve the discrepancy."

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Humans and nature: The distance is growing

The idea that humans are facing a global extinction of experience of nature is popular, but there is poor empirical evidence of its reality. To shed more light on this, the scientists measured how the average distance from an individual's home to the nearest area with low human impact changed in the last decade. They found that humans currently live 9.7 km away from a natural area on average, which is 7% further away than in the year 2000. Europe and East Asia have the highest average distance to natural areas, such as 22 km in Germany and 16 km in France. "What is striking is that all other countries in the world are following a similar pattern," explains first author Dr Victor Cazalis, a postdoctoral researcher at iDiv and Leipzig University.

The authors also showed that tree cover within cities has declined worldwide since 2000, particularly in Central Africa and South-East Asia. "This finding suggests that the possibility for the urban population to access green spaces is reducing as well," concludes Dr Gladys Barragan-Jason, a researcher at the Theoretical and Experimental Ecology Station and co-author of the study. "Indeed, the study reveals that the destruction of natural areas combined with a strong increase in urban population is leading to a growing spatial distance between humans and nature, especially in Asia, Africa and South America."

In the same study, the authors systematically searched for scientific publications assessing a trend in experiences of nature: from direct ones such as hiking in national parks, to vicarious experiences like natural settings in cultural products like cartoons, computer games or books. They found that the number of studies assessing these trends was very low (N=18), with a strong bias towards the US, Europe and Japan. This shows that any claim about the extinction of nature experience is based on poor evidence and that more studies should investigate this question, especially in Africa, Latin America and Asia.

The 18 studies found by the authors show for instance a decline in visits to nature parks in the US and Japan, a decrease in camping activities in the US, and a decrease in the number of flower species observed by Japanese children. They also find signs of disconnection in the depletion of natural elements in novels, songs, children's albums and animated movies, which are less and less imbued with natural imagery (as shown e.g. by an iDiv study from 2021).

Despite these examples of decline, other interactions are stagnating or even increasing. Watching wildlife documentaries or interacting with wild animals in video games is, for example, more common than a few years ago. "New ways of digitally interacting with nature have certainly emerged or increased in recent decades," says Gladys Barragan-Jason. "But several former studies show that these interactions have a lesser effect on our sense of connection with nature than direct interaction."

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Smelling in VR environment possible with new gaming technology

An odor machine, so-called olfactometer, makes it possible to smell in VR environments. First up is a "wine tasting game" where the user smells wine in a virtual wine cellar and gets points if the guess on aromas in each wine is correct. The new technology that can be printed on 3D printers has been developed in collaboration between Stockholm University and Malmö University. The research, funded by the Marianne and Marcus Wallenberg Foundation, was recently published in the International Journal of Human -- Computer Studies.

"We hope that the new technical possibilities will lead to scents having a more important role in game development, says Jonas Olofsson, professor of psychology and leader of the research project at Stockholm University.

In the past, computer games have focused mostly on what we can see -- moving images on screens. Other senses have not been present. But an interdisciplinary research group at Stockholm University and Malmö University has now constructed a scent machine that can be controlled by a gaming computer. In the game, the participant moves in a virtual wine cellar, picking up virtual wine glasses containing different types of wine, guessing the aromas. The small scent machine is attached to the VR system's controller, and when the player lifts the glass, it releases a scent.

"The possibility to move on from a passive to a more active sense of smell in the game world paves the way for the development of completely new smell-based game mechanics based on the players' movements and judgments," says Simon Niedenthal, interaction and game researcher at Malmö University.

The olfactometer consists of four different valves each connected to a channel. In the middle there is a fan sucking the air into a tube. With the help of the computer, the player can control the four channels so that they open to different degrees and provide different mixtures of scent. Scent blends that can mimic the complexity of a real wine glass. The game has different levels of difficulty with increasing levels of complexity.

"In the same way that a normal computer game becomes more difficult the better the player becomes; the scent game can also challenge players who already have a sensitive nose. This means that the scent machine can even be used to train wine tasters or perfumers," says Jonas Olofsson.

All code, blueprints and instructions for the machine are openly available online, as is code for the virtual wine tasting game. The research group, Sensory Cognitive Interaction Laboratory, which is located at the Department of Psychology, Stockholm University, now hopes that scented computer games can become useful for other purposes.

"For those who, for example, lost their sense of smell after COVID-19 or for other reasons, the new technology can mean an opportunity to regain their sense of smell with the help of game-based training," says Jonas Olofsson, research team leader.

Smell training is a method recommended by doctors for those who lose their sense of smell after colds and other viruses, but according to Jonas Olofsson, many people stop training because it becomes too boring.

"I hope that the fact that drawings and code are openly available as "open source" will lead to an opportunity for game companies to start creating new, commercial products for scent training using the new technology," says Jonas Olofsson.

According to Simon Niedenthal, "open source" leads to promoting accessibility, reproducibility and comparison of results in research. It also contributes to creating a cohesive research and design community within the game development field.

"But it also means that the costs of the equipment are greatly reduced, which makes it available to more people. To us that is important," says Simon Niedenthal.

"We believe in open science, that research results should be made available to the public and that other researchers should be able to repeat our results. With the help of our research, others can build scent machines and explore new ways of using scents in games," says Jonas Olofsson.

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Age vs. genetics: Which is more important for determining how we age?

Amid much speculation and research about how our genetics affect the way we age, a University of California, Berkeley, study now shows that individual differences in our DNA matter less as we get older and become prone to diseases of aging, such as diabetes and cancer.

In a study of the relative effects of genetics, aging and the environment on how some 20,000 human genes are expressed, the researchers found that aging and environment are far more important than genetic variation in affecting the expression profiles of many of our genes as we get older. The level at which genes are expressed -- that is, ratcheted up or down in activity -- determines everything from our hormone levels and metabolism to the mobilization of enzymes that repair the body.

"How do your genetics -- what you got from your sperm donor and your egg donor and your evolutionary history -- influence who you are, your phenotype, such as your height, your weight, whether or not you have heart disease?" said Peter Sudmant, UC Berkeley assistant professor of integrative biology and a member of the campus's Center for Computational Biology. "There's been a huge amount of work done in human genetics to understand how genes are turned on and off by human genetic variation. Our project came about by asking, 'How is that influenced by an individual's age?' And the first result we found was that your genetics actually matter less the older you get."

In other words, while our individual genetic makeup can help predict gene expression when we are younger, it is less useful in predicting which genes are ramped up or down when we're older -- in this study, older than 55 years. Identical twins, for example, have the same set of genes, but as they age, their gene expression profiles diverge, meaning that twins can age much differently from each other.

The findings have implications for efforts to correlate diseases of aging with genetic variation in humans, Sudmant said. Such studies should perhaps focus less on genetic variants that impact gene expression when pursuing drug targets.

"Almost all human common diseases are diseases of aging: Alzheimer's, cancers, heart disease, diabetes. All of these diseases increase their prevalence with age," he said. "Massive amounts of public resources have gone into identifying genetic variants that predispose you to these diseases. What our study is showing is that, well, actually, as you get older, genes kind of matter less for your gene expression. And so, perhaps, we need to be mindful of that when we're trying to identify the causes of these diseases of aging."

Sudmant and his colleagues reported their results this week in the journal Nature Communications.

Medawar's hypothesis

The findings are in line with Medawar's hypothesis: Genes that are turned on when we are young are more constrained by evolution because they are critical to making sure we survive to reproduce, while genes expressed after we reach reproductive age are under less evolutionary pressure. So, one would expect a lot more variation in how genes are expressed later in life.

"We're all aging in different ways," Sudmant said. "While young individuals are closer together in terms of gene expression patterns, older individuals are further apart. It's like a drift through time as gene expression patterns become more and more erratic."

This study is the first to look at both aging and gene expression across such a wide variety of tissues and individuals, Sudmant said. He and his colleagues built a statistical model to assess the relative roles of genetics and aging in 27 different human tissues from nearly 1,000 individuals and found that the impact of aging varies widely -- more than twentyfold -- among tissues.

"Across all the tissues in your body, genetics matters about the same amount. It doesn't seem like it plays more of a role in one tissue or another tissue," he said. "But aging is vastly different between different tissues. In your blood, colon, arteries, esophagus, fat tissue, age plays a much stronger role than your genetics in driving your gene expression patterns."

Sudmant and colleagues also found that Medawar's hypothesis does not hold true for all tissues. Surprisingly, in five types of tissues, evolutionary important genes were expressed at higher levels in older individuals.

"From an evolutionary perspective, it is counterintuitive that these genes should be getting turned on, until you take a close look at these tissues," Sudmant said. These five tissues happen to be the ones that constantly turn over throughout our lifespan and also produce the most cancers. Every time these tissues replace themselves, they risk creating a genetic mutation that can lead to disease.

"I guess this tells us a little bit about the limits of evolution," he said. "Your blood, for instance, always has to proliferate for you to live, and so these super-conserved, very important genes have to be turned on late in life. This is problematic because it means that those genes are going to be susceptible to getting somatic mutations and getting turned on forever in a bad, cancerous way. So, it kind of gives us a little bit of a perspective on what the limitations of living are like. It puts bounds on our ability to keep living."

Sudmant noted that the study indirectly indicates the effect on aging of one's environment, which is the impact of everything other than age and genetics: the air we breathe, the water we drink, the food we eat, but also our levels of physical exercise. Environment amounts to up to a third of gene expression changes with age.

Sudmant is conducting similar analyses of the expressed genes in several other organisms -- bats and mice -- to see how they differ and whether the differences are related to these animals' different lifespans.

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Environmental impacts of 57,000 common store-bought food products

We're all capable of slowing down the effects of a warming Earth, and it could be as simple as how we stock our pantries.

An international team of scientists has evaluated the environmental impacts of more than 57,000 food products -- the stuff you typically find as you wander the aisles of your local grocery. If this type of information is made easily available to the public, they say, it could not only enable the transition to a more sustainable food system, but chances are it could also improve people's health.

"The goal is to have a simpler, and more rigorous quantitative way to inform consumers about the tens of thousands of different items they might buy in a grocery store," said ecologist David Tilman, a professor at UC Santa Barbara's Bren School of Environmental Science & Management, and also at the University of Minnesota's College of Biological Sciences. Tilman is a co-author of a study that appears in the Proceedings of the National Academies of Science.

According to the researchers' assessment, beef and lamb take the greatest toll on the environment, with impacts far outpacing those of other proteins such as chicken, fish and seafood and nuts, which also are on the higher end of the environmental impact scale.

"Many people consider beef to taste good, and I understand why, but it is a very inefficient way to create food for humans," Tilman said. Meanwhile, processed drinks such as soda and energy drinks were rated at the lowest impact level of food products evaluated, sharing space with plant-based grocery foods such as rice and flatbreads.

A Decade of Studying Food Products

While much research has gone into the environmental impacts of food commodities such as fruits, wheat and beef, most food products contain many different ingredients, each of which have taken their own routes to become part of that product. This lifecycle data, which informs the total environmental impacts of producing, harvesting, transporting and processing of said ingredients, are largely invisible to the consumer, as are the proportions of ingredients. According to the study, this information gap exists because "the exact amount of each ingredient and their supply chain in each food product are often considered a trade secret." The sheer number of food products and their variety makes the assessment a "daunting" task for food companies and for retailers aiming to reduce their carbon emissions.

To overcome these limitations, the researchers, led by first author Michael Clark of Oxford University, used prior knowledge from ingredient lists to infer the composition of each ingredient. They then paired this information with environmental databases to gauge impacts across four indicators: greenhouse gas emissions, land use, water stress and eutrophication potential (the magnitude of excess nutrients from production that can pollute surrounding environment and waterways).

"This is the result of a decade since Mike and I started working on this," said Tilman, who is Clark's former advisor. "It started with doing some of the lifecycles ourselves, then using many of these lifecycles that were published. And then we started critically evaluating the quality of lifecycle data available for each of the major food commodities." They consulted previously published papers, conducted further analyses and used their approach on 57,000 food products found in Tesco supermarkets, a major grocery chain in the United Kingdom and Ireland.

"You go to a grocery store in Europe and it doesn't look very different from a grocery store in the United States," Tilman said. While humans around the world don't have the exact same taste preferences, he added, we tend to have to similar tastes, which results in more or less the same kind of food products in our stores.

These tastes tend to gravitate to foods that contain high levels of sugar. It's a commodity that is both cheap and produced in abundance, with effects that have led to increased rates of obesity, diabetes and other conditions related to overconsumption of highly processed foods that often contain high fructose corn syrup.

"That's what happened with the Green Revolution," Tilman said of an unintended consequence of the world's move in the 1950s and '60s toward high-yield, industrial farming processes that include pesticides, fertilizers and monocultures. "Sugar is cheap. Fats are cheap and salt is cheap. People love salty, fatty and sweet kinds of foods; that's what our taste preferences are. They made total sense during our evolutionary past, and now that these foods are so cheap and readily available, we eat them in excess."

Healthy Choices = Healthy Earth

In a previous study, Tilman and Clark found that in general, diets that included healthy, less-processed foods were also heathier for the environment. "We know there's a relationship there, and we wanted to apply this for individual foods," Tilman said. As a result, the researchers' current study also ranks grocery foods by nutritional impact, with plant-based, less processed foods on the healthier end of the scale for both humans and the environment, and highly processed grains and dairy products toward the less-healthy end.

"The healthiest diets that we know of are variants on the classical Mediterranean diet, which has many servings of fruits and vegetables a day, and whole grains," Tilman said. "Whole grain has the advantage of having fiber, which helps slow the rate at which starch becomes sugars." The main meat is fish, he added, with other meats used as flavoring and on special occasions. Other environmentally friendly and nutritious diets include vegetarian and pescatarian diets, provided hydrogenated fats and sugars are kept to a minimum. There isn't enough scientific data yet to put the vegan diet in the same group, but Tilman suspects it belongs there as well.

Still, more work needs to be done to refine the researchers' assessment. There's a lot of variability in the proportion and type of ingredients in similar grocery store foods that can lead to differences in health and environmental impacts, and there are also alternative processes to consider, Tilman said. But the hope is that this information becomes widely available, empowering consumers to make better food choices for the health of both their bodies and the environment.

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Ragweed allergy: Aggressiveness of pollen is determined by its place of origin and by the environment

The different geographic and climatic regions from which ragweed pollen originates, as well as the degree of environmental pollution, may influence the severity of allergic reactions such as hay fever and asthma. Pollen from plants in different areas exhibit different levels of aggressiveness. This is the conclusion reached by an inter-university study team led by MedUni Vienna and involving the University of Vienna and the University of Natural Resources and Applied Life Sciences. The study was recently published in the journal Frontiers in Allergy.

The research team developed an allergy model in which mice inhaled pollen from ragweed plants (Ambrosia artemisiifolia) collected in different geographic locations. They found that even a small amount of pollen (a total of 180 pollen grains) is sufficient to produce an allergic reaction, much less than the high pollen concentrations found in the air during the seasonal flowering period. As a result of climate change, the European flowering season is getting longer, and the plant is able to spread to more northerly areas. Furthermore, the regional origin of the pollen determines the severity of the allergic reaction it produces. The lead researcher and coordinator of the "Atopica" project, Michelle Epstein from MedUni Vienna, explained: "Our study shows that pollen from distinct environments can differ in its aggressiveness. So not only the concentration of the pollen in the air but also intrinsic changes (from within) related to the environment could alter the pollen's ability to sensitise and cause more severe allergic symptoms."

Wolfram Weckwerth, Professor at the Department of Functional and Evolutionary Ecology of the University of Vienna and one of the authors, said: "We now know that environmental factors change the aggressiveness of pollen. The next steps are further characterisation of the pollen, especially at the molecular level, to unambiguously identify the mixture of allergenic components." Anke Bellaire, a collaborator at the Department of Structural and Functional Botany at the Department of Botany and Biodiversity, University of Vienna, and also one of the authors, added: "Following these exciting results, we plan to continue ultrastructural subcellular analysis of ragweed pollen for further characterisation."

Gerhard Karrer, professor of botany at the University of Natural Resources and Applied Life Sciences, who was part of the team that collected the pollen in Austria, said: "The control of ragweed is a major public health concern and an adaptation strategy for mitigating and managing the impacts of climate change."

According to the researchers, there is a high probability that climate change and other environmental factors will also affect a number of other pollen-producing plants. This applied research model now provides a strategy for further studies investigating the impacts of climate change on pollen allergy.

33 million Europeans suffer from ragweed allergy

Ragweed (Ambrosia artemisiifolia) is a highly allergenic plant whose pollen causes hay fever in sensitized people and can lead to asthma. Currently, over 33 million Europeans suffer from ragweed allergy and researchers predict an increase to 77 million cases by 2060 as a result of climate change. The EU's annual economic burden of allergic asthma is already estimated to be as much as €151 billion. Ragweed is an invasive plant that is spreading particularly rapidly in Europe in the French Rhône Valley, in northern Italy, Hungary and Croatia. The season begins in August and extends throughout autumn. However, with global warming, the season is getting longer, and warmer temperatures will encourage ragweed plants to grow in more northerly areas and at higher altitudes. A single plant can produce about a billion grains of pollen per season, and these can travel over a thousand kilometres on the wind.

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