Proteins roll the dice to determine bee sex

 To date it has been unclear exactly how the sex of a bee is determined. A research team from Heinrich Heine University Düsseldorf (HHU) comprising biologists and chemists has now identified a key gene and the molecular mechanism linked with it. In the current issue of the scientific journal Science Advances, they describe how this process is similar to a game involving two dice.

The sex of a living creature has significant consequences for its form, function and behaviour. The biological sex of an organism is usually determined at the start of its life. In humans, for example, the presence of the sex-determining "Y chromosome" decides whether a man will be born.

The Silesian priest Johann Dzierzon already examined the sex-determining mechanisms of honeybees (Apis mellifera) back in 1845. Among other things, he discovered the asexual reproduction of male bees -- the "drones."

Bees -- unlike humans -- do not have just one sex-determining chromosome. A research team headed by Professor Dr Martin Beye from the Institute of Evolutionary Genetics at HHU has now established that the sex is determined by a single gene, referred to as "Csd" (Complementary sex determiner) via a special mechanism.

This gene can have more than 100 variations, so-called alleles. In other cases, e.g. in flowers, the various alleles of a gene can determine petal colour.

In the case of sexual fertilisation, the simple chromosome sets from the egg and sperm cells come together to create a double -- diploid -- chromosome set. Accordingly, two Csd gene variants are now present in each sexually fertilized bee.

The next finding of the bee researchers in Düsseldorf: Where the two alleles of the Csd gene are different, a female bee develops. By contrast, if the alleles of the gene are the same on both chromosomes, a male bee develops. However, as the bees want to prevent this to avoid inbreeding, the worker bees do not raise these eggs.

The question remained as to how this sex determination occurs at molecular level. Lead author Dr Marianne Otte: "It is necessary to know here that each different allele of the Csd gene produces a different variant of the associated Csd protein, all of which differ slightly. We were able to demonstrate that only different Csd proteins can bind with each other and thus activate a molecular switch that determines 'female bee'. By contrast, if the proteins are the same, they bind differently and the switch is not activated. In this case, a male bee would develop, but it is not raised."

Professor Beye, last author of the study in Science Advances: "It is similar to a molecular game involving two dice: However, in this case, the throw that produces a double is not the winner. Instead, the throw must produce two different numbers to enable a new bee -- a female -- to be raised."

By contrast, the drones develop from unfertilised eggs. Accordingly, these male bees only have a simple chromosome set with identical Csd proteins. The queen bee decides not to add sperm to the egg during the laying process.

Dr Otte: "We have been able to solve a genetic mystery that has existed for more than 100 years by tracing it back to the switch function of the Csd protein." Professor Beye comments on further research questions: "The mechanism the worker bees use to identify whether the fertilised egg contains two different Csd proteins and is thus switched to 'female' is still unknown. As it is dark inside the hive, there must be an olfactory clue."

The results will be used to advance bee breeding measures.

Early human migrants followed lush corridor-route out of Africa

 n international team of scientists has found early human migrants left Africa for Eurasia, across the Sinai peninsula and on through Jordan, over 80-thousand years ago.

Researchers from the University of Southampton (UK) and Shantou University (China), together with colleagues in Jordan, Australia and the Czech Republic, have proved there was a "well-watered corridor" which funnelled hunter-gatherers through The Levant towards western Asia and northern Arabia via Jordan.

Their findings, published in the journal Science Advances, support previous research conducted in Arabia suggesting this green, overland route, which is now desert, was favoured by travelling Homo sapiens heading north.

'Modern' humans evolved in Africa between 300 and 200 thousand years ago and dispersed out of the continent in several stages. It's thought that over tens of thousands of years they went on to populate Asia and then Europe.

For this latest research, the team conducted fieldwork in the Jordan Rift Valley where they uncovered hand tools, known as 'flakes', on the edge of wadis -- now dry river channels which, tens of thousands of years ago, were full of water. The scientists used luminescence dating techniques to help establish the age of the sediment the tools were buried in. This method estimates how long it has been since sediment was last exposed to light.

The results showed the tools were likely to have been used approximately 84 thousand years ago and then abandoned on the banks of the wadis and subsequently buried over time.

Paul Carling, Professor of Geomorphology at the University of Southampton, comments: "It's long been thought that when the sea level was low, humans used a southern crossing, via the Red Sea from the horn of Africa, to get to southwestern Arabia. However, our study confirms there was a well-trodden passage to the north, across the only land-route from Africa to Eurasia.

"Our newly published evidence is a key piece of the puzzle that shows humans migrated using a northern route -- using small wetland areas as bases whilst hunting abundant wildlife in the drier grasslands. Although previous studies have looked for large lakes as potential watering holes, in fact small wetlands were very important as staging posts during the migration."

Dr Mahmoud Abbas, the study's lead author from Shantou University, China, said: "The Levant acted as a well-watered corridor for modern humans to disperse out of Africa during the last interglacial, and we have now demonstrated this is the case in the Jordan Rift Valley zone.

"The paleohydrological evidence from the Jordan desert enhances our understanding of the environmental setting at that time. Rather than dry desert, savannah grasslands would have provided the much-needed resources for humans to survive during their journey out of Africa and into southwest Asia and beyond."

The researchers say their study demonstrates the intimate relationship between climate change, human survival and migrations.

Two-dimensional compounds can capture carbon from the air

 Some of the thinnest materials known to humankind may provide solutions to scientists in their quest to curb the effects of global warming.

Known as MXene and MBene compounds, these substances are only a few atoms thick, making them two-dimensional. Because of their large surface area, the materials have the potential to absorb carbon dioxide molecules from the atmosphere, which could help reduce the harmful effects of climate change by safely sequestering carbon dioxide.

In a paper published Oct. 4 in the journal Chem, UC Riverside professor Mihri Ozkan and her co-authors explain the potential of MXenes and MBenes in carbon capture technologies.

"In this review, we conducted an exhaustive analysis and proposed strategies for the widespread implementation of these materials in large-scale applications," said Ozkan, a climate action professor in UCR's Electrical and Computer Engineering Department at the Bourns College of Engineering.

"Their unique properties make them excellent candidates for capturing carbon dioxide."

According to Ozkan, these two-dimensional materials can be engineered to selectively capture carbondioxide. One of their key advantages is their high selectivity towards carbon dioxide, which can be attributed to a process called interlayer distance engineering. Additionally, the materials are mechanically stable and maintain their structural integrity even after multiple cycles of carbon capture and release.

graphic As human-caused carbon dioxide emissions continue to increase, developing carbon-capture technologies has become a top priority. It is projected that the planet's temperature could rise by 1.5°C above pre-industrial levels within the next decade, leading to more frequent severe weather events, worsening drought, crop failures, increased levels of human migration, and political instability. These negative impacts highlight the urgent need for action to curb carbon emissions and mitigate the effects of climate change.

Scientists at Drexel University in Philadelphia, Pa., discovered MXenes and MBenes in the early 2010s. MXene is an inorganic compound made up of atomically thin layers of transition metal carbides, nitrides or carbonitrides. On the other hand, MBenes are dimensional transition metal borides made from boron. These compounds are produced through chemical etching techniques and have crystalline lattices with repeating orthorhombic and hexagonal structures.

Ozkan explained that these materials can be used in conjunction with existing technologies, such as those developed by the Swiss company Climework AS. These systems extract carbon dioxide directly from the atmosphere and sequester it for safe and long-term storage.

Before these compounds can be used in carbon capture devices, several technical issues need to be resolved, according to Ozkan. First and foremost, scientists must address the bottlenecks associated with synthesis-related challenges in large-volume production. Other obstacles to large-scale manufacturing include non-uniform mixing, temperature gradients, and problems with heat transfer, among others.

Still, these hurdles can be overcome.

A top-down approach is ideal for large-scale MXene synthesis by scaling up wet etching methods or developing new ones, according to Ozkan.

Climate intervention technologies may create winners and losers in world food supply

 A technology being studied to curb climate change -- one that could be put in place in one or two decades if work on the technology began now -- would affect food productivity in parts of planet Earth in dramatically different ways, benefiting some areas, and adversely affecting others, according to projections prepared by a Rutgers-led team of scientists.

Writing in the journal, Nature Food, the scientists described the results of computer models simulating varying climate scenarios and their impacts over time on the production of the world's four major food crops: corn, rice, soybeans and wheat in all locations where they are grown.

Some scenarios were produced by simulated stratospheric aerosol intervention (SAI), also known as geoengineering, to halt or reverse climate change, while others, for comparison purposes, weren't. The SAI scenario, inspired by volcanic eruptions, would involve spraying sulfur dioxide gas into the stratosphere. By placing a cloud of what becomes sulfuric acid in the upper atmosphere continuously, the process would shield the Earth from the Sun, cooling it.

"Not one of the 11 climate change or climate intervention scenarios we analyzed benefits everyone," said Brendan Clark, a doctoral student in the Department of Environmental Sciences at the Rutgers School of Environmental and Biological Sciences (SEBS), and lead author on the study. "Nations may have different ideas of what constitutes an optimal global temperature, which could lead to conflicts. It would be like people fighting over the thermostat in a house, but on a global scale."

The models showed marked differences in agricultural productivity depending on where a country is positioned on the globe. Continued, uncontrolled climate change, the models revealed, favors crop production in the cold, high-latitude areas, such as Canada, Russia, the U.S. northern border states, Scandinavia and Scotland.

Moderate amounts of atmospheric sulfur spraying, which may either halt or slightly lower global average temperatures, favors food production in the temperate regions known as the mid-latitudes, where most of the large land masses of North America and Eurasia are located, according to the analysis.

Large amounts of climate intervention to significantly reverse warming and lower the global average temperature would favor agricultural production in the tropics, the region of Earth around the equator. In the Western Hemisphere, the region includes Mexico, all of Central America, the Caribbean and the top half of South America. In the Eastern Hemisphere, the tropics include most of Africa, parts of the Middle East, most of India, all of Southeast Asia, most of Australia and most of the island nations of Oceania.

Double trouble: Infamous 'eagle killer' bacterium produces not one, but two toxins

 The cyanobacterium Aetokthonos hydrillicola produces not just one, but two highly potent toxins. In the latest issue of the journal Proceedings of the National Academy of Sciences (PNAS), an international team led by Martin Luther University Halle-Wittenberg (MLU) and Freie Universität Berlin describes the second toxin, which had remained elusive until now. Even in low concentrations, it can destroy cells and is similar to substances currently used in cancer treatment. Two years ago, the same team established that the first toxin from the cyanobacterium is the cause of a mysterious disease among bald eagles in the USA.

Aetokthonos hydrillicola is particularly challenging for researchers. It is notoriously difficult to cultivate and produces one of its toxins only under specific conditions. The fact that it produces two toxins with very different chemical makeups is also unusual. Cyanobacteria normally produce only one toxin -- and A. hydrillicola was established as the source of aetokthonotoxin in 2021. This discovery was made by Professor Susan Wilde from the University of Georgia (USA) and Professor Timo Niedermeyer, who worked at MLU until July 2023 and has now joined the researchers at Freie Universität Berlin. This toxin solved a riddle that had kept scientists busy for decades: it triggers the disease vacuolar myelinopathy (VM) among bald eagles in the United States. VM causes holes to form in the brain and, as a result, the birds lose control of their bodies. Science ran the breakthrough as a cover story at the time, and the international team picked up several awards for its work.

Markus Schwark from MLU was able to provide evidence of the second, previously unknown toxin and characterized the compound in detail. "We were very surprised when we worked out the structure of this toxin. It resembles toxins that have been found in marine cyanobacteria. They are even already being used in cancer-cell killing drugs," says Schwark. Based on the bacterium and the similar, known toxins, the researchers have named the newly discovered toxin "aetokthonostatin."

Scientists have suspected that this toxin exists for some time: "During one of our first investigations over ten years ago, we discovered that an extract of the cyanobacterium is highly toxic for cells. We assumed that this effect points to aetokthonotoxin that triggers the avian disease," says Timo Niedermeyer. However, further examinations revealed that the bird toxin only causes minor direct cell damage. Extracts with zero aetokthonotoxin content still destroyed cells even in extremely low concentrations. So A. hydrillicola had to be producing another very powerful toxin.

A team from the Czech Academy of Sciences led by Dr. Jan Mareš was able to determine which genes in the cyanobacterium are behind the synthesis of the new toxic molecule. Since the compound is similar to substances that are used in antitumor medicine, the findings could help to develop new drugs that fight cancer.

The cyanobacterium is also thriving in American lakes and rivers that feed the drinking water network. The scientists therefore recommend monitoring these waters more frequently for Aetokthonos hydrillicola and its two toxins to avoid potential risks to human health.

Researchers build and test a framework for achieving climate resilience across diverse fisheries

 What makes for a successful climate-resilient fishery, one that sustainably produces resources for human benefit despite increasing climate stressors and human impacts? It's a question that faces present and future fisheries, their practitioners and fishing communities as the world turns to the ocean to feed its growing population.

"For a fishery to be resilient it needs to be able to prepare for, resist, cope with, recover from, or adapt to any given impact," said Jacob Eurich, who is a research associate at UC Santa Barbara's Marine Science Institute, and a fisheries scientist at the Environmental Defense Fund (EDF). "In most cases a fishery will need to have a combination of these capacities to continue to produce food, income and well-being to the people who rely on them."

It's not a one-size-fits-all situation, according to Eurich, who led an international cohort of researchers for a paper published in the journal Fish and Fisheries. Because fisheries are complex marine ecosystems that face unique combinations of circumstances across the globe, achieving climate resilience will require equally diverse strategies, he said.

Fortunately, there are climate resilience success stories to draw lessons from. To gain these valuable insights, Eurich and colleagues examined 18 fisheries that expand our knowledge about how resilience operates across the world. They tested these fisheries' resilience attributes to learn how and why they were able to persist despite climate change and human impact and, importantly, for whose benefit. The researchers then synthesized their findings into fishery archetypes and resilience pathways for other fishery practitioners that aspire to increase levels of resilience and sustainable benefits to society.

Diverse fisheries, diverse strategies

For a fishery to be successful in the face of climate change, it must be effective across ecological, social and governance dimensions -- that is, be able to not only support the health and productivity of its resources but also be supported to that end in its operations and its role in society.

"The biggest challenge is that every fishery is different," Eurich said. "Each fishery has different characteristics and operates on different scales, for different reasons and with unique goals." The survey conducted by the research team -- from the Science for Nature and People Partnership (SNAPP) Climate Resilient Fisheries Working Group, which was led by the Gulf of Maine Research Institute (GMRI), Cornell University and EDF and convened at UCSB's National Center for Ecological Analysis & Synthesis (NCEAS) -- provided the data for a framework that standardized, prioritized and scored 38 attributes of fisheries and their milieu. This system allowed the researchers to find strengths and commonalities to which other fisheries under similar circumstances may align to increase their own resilience.

Pathways to resilience

The researchers developed five archetypes of climate-resilient fisheries and detailed two pathways to climate resilience. They found that in some fisheries, climate resilience is derived from strong ecological assets and tight-knit communities that promote flexible governance, despite having limited economic avenues outside of fishing. In these fisheries, the non-monetary benefits of fish, such as nutrition and culture, are distributed broadly. However, the shift to globalized economies can disrupt this model.

In other fisheries, robust governance and economic assets drive the efficient conversion of fish into economic benefits. Competition, coupled with access to knowledge and capital for investment, can spur technological advancement, which often results in responsive governance. However, in these fisheries, wealth might become concentrated among the most successful firms, leading to power imbalances and enabling only a select group to withstand losses or capitalize on new economic opportunities posed by climate change.

"We also identified key priority areas, where a deficiency in certain attributes hindered fishery resilience," Eurich added. "Often, fishery practitioners know the climate-ready management interventions needed in their system but political obstacles and a lack of support or capacity block these changes. By taking the time to identify and enhance inhibiting attributes, practitioners can increase the success of long-term interventions."

Next steps

Lily Zhao, a Ph.D. student in the UCSB's Department of Ecology, Evolution and Marine Biology, who co-led the piece, added that "There's still a lot of work to be done to ensure sources of resilience are distributed equitably to support climate adaptation within fishery systems, so I'm excited to see how priority areas we found like equitable and inclusive governance will be built and emphasized in the coming decades."

The framework for assessing fishery resilience and research findings have also been converted to an interactive decision support tool. The Climate-Resilient Fisheries Planning Tool guides users through a six-step process that will provide key elements needed to develop a fishery resilience plan.

Disaster-proofing sustainable neighborhoods requires thorough long-term planning

 Individual neighbourhoods will be intimately involved in providing local solutions to collective problems. One measure will be distributed renewable energy production -- energy produced at local levels, either by solar technology, wind or other methods, will push cities to achieve their net-zero targets.

However, even these power-generating neighbourhoods will remain vulnerable to power outages resulting from natural disasters such as hurricanes, fires or floods. And all of these are likely to become increasingly common due to the effects of climate change. So how will sustainable neighbourhoods cope with the pressures put on their energy systems?

Caroline Hachem-Vermette is an associate professor in the Department of Building, Civil and Environmental Engineering at the Gina Cody School of Engineering and Computer Science. In a new paper, she looks at how thoughtful design can reduce a neighbourhood's energy vulnerability during power disruptions, as well as which design characteristics are needed if and when local populations need to move to shelters.

The article was published in the journal Renewable and Sustainable Energy Reviews. In it Hachem-Vermette and co-author Kuljeet Singh from the University of Prince Edward Island analyse the design and energy characteristics of particular kinds of buildings and neighbourhoods to assess their vulnerabilities and their access to alternative and renewable energy sources. The authors use several scenarios involving different lengths of power disruption to see which kind of response is most beneficial to the populations affected.

"We focused on the neighbourhood unit level because we can look at characteristics and detail levels that are harder to find at the city level," Hachem-Vermette explains.

"Designed to be self-contained in terms of basic conveniences and services, the neighbourhood unit is a fundamental concept in urban planning. Neighborhood units serve as a basis for city-level development and design and can be used to understand various sustainable and resilient strategies."

Net-zero but still vulnerable

Designed along sustainable practices, the theoretical neighbourhoods were based on the kinds found in typical Canadian municipalities: low-density residential, mixed residential/commercial and retail, high-density residential and mixed high-density residential and industrial. The researchers also assessed the types of energy systems these neighbourhoods primarily relied on to provide electrical and thermal energy.

These indicators were considered across scenarios in which power disruptions lasted between one day and over three weeks. They provided reliable estimates regarding energy interruption vulnerability as well as the best measures to be considered to mitigate the effects of these disasters on local populations.

The researchers came away from their study with several recommendations that could improve a stricken neighbourhood's resilience. They urged municipal authorities to do the following: equip large buildings such as schools with the means to be self-sufficient in energy production so they could be used as temporary shelters; modify design standards for shelters to increase their maximum population while still providing good indoor air quality, hygienic spaces for living, food preparation and recreation; and incorporate neighbourhood spatial design methods to ensure access to roads, potential shelter buildings and hospitals, and landscapes for energy system installations.

Hachem-Vermette realizes much more study is needed as cities move toward fully sustainable practices in the face of increasingly extreme weather. But she is confident that initiatives such as Concordia's PLAN/NET ZERØ and the $123-million dollar Canada First Research Excellence Fund grant announced earlier this year will help her and her fellow researchers find pathways to navigate the societal transition to renewable energy sources.

"My research is at the heart of the effort to build neighbourhoods that are decarbonised," she says. "With my background in architecture, urban planning and building engineering, I can pull these disciplines together. Bridging the gaps at the interface of these disciplines is where we will find sustainable and resilient solutions."

Controlled burns help prevent wildfires; Climate change is limiting their use

 Prescribed fires, sometimes called controlled burns, are one of the most common tools for preventing catastrophic wildfires in the Western United States. Lit by highly trained firefighters, they help clear away excess dry plant matter that might otherwise turn a healthy vegetation fire into a raging inferno.

To safely carry out controlled burns, firefighters must wait for specific weather conditions: not so damp as to prevent combustion, but not so dry or windy as to burn more vegetation than intended. These conditions limit the opportunities.

Now, a new study led by UCLA climate scientist Daniel Swain has found that that climate change is further reducing the overall number of days and changing the times of year when prescribed fires can be safely used.

Currently, scientists project warming of 2.0 degrees Celsius (3.6 degrees Fahrenheit) by 2060 -- a projection Swain called "optimistic" given the current trajectory of even greater warming. Still, these temperatures would reduce the number of days when weather and vegetation conditions favor prescribed fires by 17% on average across the Western U.S.

Most reductions would come in spring and summer, when most prescribed burns are currently implemented. Yet in winter, the research projects a net 4% increase in the number of favorable days for prescribed fire.

Paper co-author Kristen Shive, a UC Berkeley expert on forests, wildfires and prescribed fire, said specific burn prescriptions vary by location and vegetation type, but target temperatures commonly range from 50-70 degrees Fahrenheit with 10-20% relative humidity.

Climate change will require the agencies responsible for prescribed burns to adjust, Swain said, because most personnel who prepare for and manage prescribed fires are seasonal workers whose jobs end by mid-autumn each year. Going forward, the use of prescribed fires will require changes in staff availability.

"Global warming will reduce the number of favorable days for prescribed fires throughout the American West, but winter in particular may emerge as an increasingly favorable time for prescribed burns if the relevant policy and staffing changes can be made," Swain said.

The researchers also found regional variation in the changes. In California, for example, the changes are most pronounced in coastal and southern parts of the state, with many places losing a month of days suitable for prescribed fires each year. The northern parts of the Rocky Mountains, on the other hand, may see a modest increase in days when it's safe to use these fires.

Yet not much will change in the short term, according to Swain.

"We're just not doing a lot of prescribed fire compared to what is needed, at scale, to really address the escalating wildfire crisis," he said.

The study, published in Communications Earth and Environment, a Nature journal, included research from UCLA, UC Berkeley, UC Merced and the Nature Conservancy. It focused on historical and projected climate conditions and vegetation dryness, comparing 1980-2020 with 2020-2060. The researchers did not address other factors important to the use of prescribed fire: impact on ecology, public policy considerations, effects of smoke on humans and wildlife, and availability of staff to do prescribed burns.

As wildfires in the American West have dramatically increased for a variety of reasons -- including climate change, human development in fire-prone areas and aggressive fire suppression in the 20th century -- tools like prescribed fires will only become more critical. Anticipating future opportunities and limitations to the use of this tool enables agencies to plan ahead, particularly as regards the firefighting work force.

"This paper is giving us advanced warning," Shive said. "Hopefully we can change policies to either extend those folks or create winter-specific crews."

Global consortium creates large-scale, cross-species database and universal 'clock' to estimate age in all mammalian tissues

 Scientists at UCLA David Geffen School of Medicine and UCLA Health led an international research team that published two articles detailing changes in DNA -- changes that researchers found are shared by humans and other mammals throughout history and are associated with life span and numerous other traits.

"We've discovered that the life spans of mammals are closely associated with chemical modifications of the DNA molecule, specifically known as epigenetics, or more accurately, methylation. In essence, mammals with longer life spans exhibit more pronounced DNA methylation landscapes, whereas those of shorter-lived species have more subdued, flatter methylation patterns," said the senior author of both articles, Steve Horvath, PhD, ScD, an expert on the aging process and a professor in human genetics and biostatistics at UCLA at the time the studies were conducted.

Jason Ernst, a professor of biological chemistry, computer science, and computational medicine at UCLA, said, "The technology we designed to measure DNA methylation levels across mammals along with the tissue sample contributions from a large consortium of researchers led to the production of a highly unique data set, which, when analyzed with advanced computational and statistical tools, unveiled a deeper understanding of the relationship between DNA methylation, life span, aging, and other biological processes across mammals."

The studies, one published in Science and the other in Nature Aging, focus on DNA methylation, or cytosine methylation, a chemical modification of cytosine, one of the four building blocks of the DNA molecule.

DNA methylation is a mechanism by which cells can control gene expression -- turning genes on or off. In these studies, the researchers focused on DNA methylation differences across species at locations where the DNA sequence is generally the same.

To study the effects of DNA methylation, the nearly 200 researchers -- collectively known as the Mammalian Methylation Consortium -- collected and analyzed methylation data from more than 15,000 animal tissue samples covering 348 mammalian species. They found that changes in methylation profiles closely parallel changes in genetics through evolution, demonstrating that there is an intertwined evolution of the genome and the epigenome that influences the biological characteristics and traits of different mammalian species.

Among the Science study's findings:

• Methylation, as evidenced by the epigenetic "marks" it leaves, bears a substantial correlation with maximum life span across mammalian species. Looking at methylation profiles on the DNA molecule as terrain with peaks and troughs, Horvath commented that species with long lives have prominent peaks and valleys, developed during extended gestation and development periods. In contrast, short-lived species have short gestation periods and rapid development, resulting in cells with a flatter, less-defined methylation landscape.
• Maximum life span of a species is associated with specific developmental processes, as suggested by the involvement of certain genes and genetic transcription factors.
• Cytosines whose methylation levels correlate with maximum life span differ from those that change with chronological age, suggesting that molecular pathways pertaining to average life span within a species are distinct from those determining the species' maximum life span.
• Evolution acts not only at the genetic level, but also at the epigenetic level. "Our results demonstrate that DNA methylation is subjected to evolutionary pressures and selection," said the authors, whose database has been made public for other researchers.

Horvath and the consortium researchers used a subset of the database to study the methylation profiles of 185 species of mammals. Identifying changes in methylation levels that occur with age across all mammals, they developed a "universal pan-mammalian clock," a mathematical formula that can accurately estimate age in all mammalian species. Results of this study are published in Nature Aging.

Horvath and a UCLA team introduced the concept of an epigenetic clock for age measurement, using human saliva samples, in 2011. Two years later, Horvath demonstrated that cytosine methylation enables the creation of a mathematical model for estimating age across all human tissues. The new work, which describes universal clocks, demonstrates that a single formula can accurately estimate age across mammalian tissues and species.

Among the Nature Aging study's findings:

• The pan-mammalian clocks maintain their high accuracy across species with varying life spans, from short-lived mice and rats to long-lived humans, bats and whales.
• The universal pan-mammalian clocks are predictors of mortality risk in humans and mice, which suggests they could prove valuable for preclinical studies. Therefore, an intervention that reverses epigenetic age in a mouse, according to the clock, might be applicable to humans as well.
• The study identified specific regions in the genetic material of cells that either gain or lose methylation with chronological age.
• The research revealed that developmental genes play a role in the functioning of epigenetic clocks.
• The research connects developmental pathways with chronological aging effects and tissue degradation. This refutes the long-standing belief that aging is driven solely by random cellular damage that accumulates over time. Instead, the epigenetic aspects of aging follow a predetermined "program."
• The discovery of the pan-mammalian clocks provides compelling evidence that aging processes are evolutionarily conserved -- remaining consistent through time -- and are closely linked with developmental processes across all mammalian species.

Novel machine-learning method produces detailed population trend maps for 550 bird species

 Scientists at the Cornell Lab of Ornithology have developed a novel way to model whether the populations of more than 500 bird species are increasing or decreasing. The method solves a nagging statistical problem by accounting for year-to-year changes in the behavior of people collecting the data. The result is detailed trend maps for each species down to an eight-mile radius -- a major boost for local conservation efforts. Scientists used an approach called Double Machine Learning. Details are published in the journal Methods in Ecology and Evolution.

"Changing human behavior presents a problem for statistical analysis of data collected by volunteers," explained lead author Daniel Fink at the Cornell Lab. "For example, is a particular species really declining in a region -- or are there simply fewer people making observations in the bird's preferred habitat compared to past years?"

Birding behavior may change when people adopt new tools, get better at identifying birds, or go birding in new areas. Changes in human behavior become what is called a "confounding" factor. A confounding factor has an impact on the primary question being studied and can distort reality. In this case, changes in the recorded abundances of birds may be real, or they may be artifacts that appear because of changes in the observation process over time.

Double Machine Learning is applied to bird observation data collected by the Cornell Lab's global eBird program and then visualized with detailed maps. With Double Machine Learning, two types of patterns are "learned" and then identified in the data. One pattern is the variation in the reported counts of birds. The second pattern reflects variation in birders' behavior. The effect of the behavior pattern is then removed, leaving only variation in the actual recorded abundances of birds.

"Now, we have a way to analyze these data that produce robust estimates of population change, even for species and/or regions without rigorous monitoring programs," said Fink. "The ability to estimate trends while accounting for confounding factors inherent in citizen science data has the potential to fill important information gaps."

Chemicals from maize roots influence wheat yield

 Maize roots secrete certain chemicals that affect the quality of soil. In some fields, this effect increases yields of wheat planted subsequent to maize in the same soil by more than 4%. This was proven by researchers from the University of Bern. While the findings from several field experiments show that these effects are highly variable, in the long term they may yet help to make the cultivation of grains more sustainable, without the need for additional fertilizers or pesticides.

Plants produce an abundance of special chemicals. Some of these are released into the soil and influence its quality. This, in turn, affects the next plant to grow in the soil. So far, little research has taken place on the extent to which the excreted chemicals can be used in agriculture to increase productivity. Recently, however, researchers from the Institute of Plant Sciences (IPS) at the University of Bern have conducted field experiments in this area. With their findings published in the scientific journal eLife, the researchers demonstrate that specialized metabolitesfrom the roots of the maize plant can bring about an increase in the yields of subsequently planted wheat under agriculturally realistic conditions.

How maize root chemicals affect wheat

On the basis of earlier studies conducted by researchers at the Institute of Plant Sciences (IPS) at the University of Bern, it was known that so-called benzoxazinoids -- natural chemicals which maize plants release through their roots -- change the composition of microorganisms in the soil on the roots and therefore influence the growth of the subsequent plants that grow in the soil. The present study investigated whether plant-soil feedbacks of this kind also occur under realistic agricultural conditions. "Such field experiments are essential to test the transferability of basic research into practice and thus assess the potential agronomic benefit," explains Valentin Gfeller, who worked on the project as a doctoral student at IPS and now works at the Research Institute of Organic Agriculture FiBL. During a two-year field experiment, two lines of maize were initially grown, only one of which released benzoxazinoids into the soil. Three varieties of winter wheat were then grown on the differently conditioned soils. On this basis, it was possible to demonstrate that the excretion of benzoxazinoids improves germination and increases tillering, growth and crop yield.

Fewer pests, same quality

In addition to the increased crop, lower levels of infestation by some pests were also observed. "A yield increase of 4% may not sound spectacular, but it is still significant considering how challenging it has become to enhance wheat yields without additional inputs," explained Matthias Erb, Professor for Biotic Interactions at the Institute of Plant Sciences, who led the study together with Klaus Schläppi of the University of Basel. "Whether effects of this kind actually make a significant difference for overall agricultural productivity and sustainability remains to be seen, however, as yield also depends on many other factors," explains Erb. The study demonstrates the potential of using specialized plant compounds to improve crop productivity through variety-specific rotations.

Within the framework of the "One Health" Interfaculty Research Cooperation (IRC) at the University of Bern (see box), it was also possible to investigate the quality of the wheat at the level of individual chemical elements. Together with the Institute of Geography of the University of Bern and Agroscope, the Swiss centre of excellence for agricultural research, it was possible to demonstrate that the increase in harvest due to benzoxazinoids does not have any negative impact on wheat grain quality.

Plant chemicals persist in the soil

To better understand the underlying mechanism, the researchers completed a variety of analyzes of the soil and roots. The benzoxazinoid-producing plants accumulated these chemicals and their degradation products in the soil close to their roots. Furthermore, in collaboration with the University of Basel, it was confirmed that benzoxazinoids influence the community of bacteria and fungi in and on maize roots. However, soil nutrients were not altered. Benzoxazinoids also proved to be particularly persistent in the soil. The extent to which wheat growth and overall yield are directly or indirectly affected by benzoxazinoids through soil microorganisms will be subject to further investigation.

Soil properties are important

To test the effects of soil properties, together with the University of Basel and Agroscope, the research team conducted another two-year field experiment to investigate how these plant-soil feedbacks from benzoxazinoids act in a more heterogeneous field. The composition of the soil chemistry and microorganisms in the field in question varied considerably. The researchers succeeded in showing that the influence of benzoxazinoids on the growth and resistance of wheat depends on this different composition. "A better understanding of the effects of soil properties on plant-soil feedbacks is crucial in terms of the future use in sustainable agriculture," explains Valentin Gfeller.

Even treated wastewater affects our rivers

 Effluents from wastewater treatment plants have a dual effect: Some species disappear, while others benefit. Especially certain insect orders, such as stonefly and caddisfly larvae, are decimated. Certain worms and crustaceans, by contrast, can increase in number. A team from Goethe University Frankfurt led by Daniel Enns and Dr. Jonas Jourdan has corroborated this in a comprehensive study, which has now been published in the journal Water Research. They examined 170 wastewater treatment plants in Hesse in relation to species composition.

Wastewater treatment plants are an indispensable part of our modern infrastructure; they have made a significant contribution to improving the quality of our surface waters. However, their ability to completely remove what are known as micropollutants from wastewater is mostly limited. These substances include, for example, active ingredients from pharmaceuticals and personal care products, pesticides and other synthetic substances enter waterbodies via the treated wastewater, placing an additional burden on rivers and streams. This exacerbates the challenges faced by already vulnerable insect communities and aquatic fauna. Previous studies -- which have primarily focused on single wastewater treatment plants -- have already shown that invertebrate communities downstream of such effluents are generally dominated by pollution-tolerant taxa.

Until now, however, it was unclear how ubiquitous these changes are. That is why a team of biologists from Goethe University Frankfurt has now studied extensively how wastewater from 170 wastewater treatment plants in Hesse has an impact on the species composition of invertebrates. This has prompted a change in the common conception that human-induced stressors reduce the number of species in a habitat and thus their diversity: Rather, the findings indicate that a shift in species composition can be observed. The researchers were able to identify significant shifts in the composition of the species community between sites located upstream and downstream of wastewater treatment plants. Some species were particularly affected by effluents from wastewater treatment plants -- such as stonefly and caddisfly larvae, which disappear entirely in some places. Other taxa, such as certain worms and crustaceans, by contrast, benefit and are found in greater numbers. This change can be observed especially in streams and smaller rivers. Overall, wastewater treatment plants alter conditions downstream to the advantage of pollution-tolerant taxa and to the disadvantage of sensitive ones.

How can we reduce water pollution?

Modern treatment techniques such as ozonation or activated charcoal filtering can make water treatment in wastewater treatment plants more efficient, allowing a wider range of pollutants, including many trace substances, to be removed from the wastewater before it is released into the environment. Merging smaller wastewater treatment plants can also contribute to reducing the burden on the environment. Whatever measures are taken, it is important to make sure that upstream sections are not already degraded and are in a good chemical and structural condition

Nature's kitchen: how a chemical reaction used by cooks helped create life on Earth

 A chemical process used in the browning of food to give it its distinct smell and taste is probably happening deep in the oceans, where it helped create the conditions necessary for life.

Known as the Maillard reaction after the French scientist who discovered it, the process converts small molecules of organic carbon into bigger molecules known as polymers. In the kitchen, it is used to create flavours and aromas out of sugars.

But a research team led by Professor Caroline Peacock at the University of Leeds argues that on the sea floor, the process has had a more fundamental effect, where it has helped to raise oxygen and reduce carbon dioxide levels in the atmosphere, to create the conditions for complex life forms to emerge and thrive on Earth.

Source of organic carbon

Organic carbon in the oceans mostly comes from microscopic living organisms. When those organisms die, they sink to the sea floor and are consumed by bacteria. That decay process uses oxygen and releases carbon dioxide into the ocean which eventually ends up in the atmosphere.

As a result of the Maillard reaction, the smaller molecules are converted into larger molecules. Those larger molecules are harder for microorganisms to breakdown and remain stored in the sediment for tens of thousands -- if not millions -- of years.

The scientists describe this as the "preservation of organic carbon."

That long-term storage or preservation of organic carbon on the seabed had major consequences for conditions that developed on the surface of the Earth. It limited the release of carbon dioxide, allowing more oxygen to reach the Earth's atmosphere and limited variation in the warming of the Earth's land surface over the last 400 million years to an average of about five degrees Celsius.

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'Too slow to have any impact'

Dr Oliver Moore, first author in the study and a Research Fellow in Biogeochemistry in the School of Earth and Environment at Leeds, said: "It had been suggested back in the 1970's that the Maillard reaction might occur in marine sediments, but the process was thought to be too slow to impact the conditions that exist on Earth.

"Our experiments have shown that in the presence of key elements, namely iron and manganese which are found in sea water, the rate of reaction is increased by tens of times.

"Over Earth's long history, this may have helped create the conditions necessary for complex life to inhabit the Earth."

As part of the study, the scientists modelled how much organic carbon has been locked into the seabed because of the Maillard reaction. They estimate it has resulted in around 4 million tonnes of organic carbon each year being locked into the seabed. That is the equivalent weight of around 50 London Tower Bridges.

To test their theory, the researchers looked at what happened to simple organic compounds when mixed with different forms of iron and manganese in the laboratory at 10 degrees Celsius, the temperature of the seabed.

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Analysis revealed that the "chemical fingerprint" of the laboratory samples -- which had undergone the Maillard reaction -- matched those from sediment samples taken from seabed locations around the world.

That "fingerprint" analysis was conducted at the Diamond Light Source in Oxfordshire, the UK's synchrotron which generates intense beams of light energy to reveal the atomic structure of samples.

Dr Burkhard Kaulich, Principal Beamline Scientist of the Scanning X-ray Microscopy beamline (I08-SXM) at Diamond Light Source, said: "Our advanced I08-SXM instrumentation with its high stability, energy and optical resolution was developed and optimised to help probe carbon chemistry and reactions which take place in environmental systems.

"We are very proud to have been able to contribute to a better understanding of the fundamental chemical processes involved in the creation of complex life forms and climate on Earth."

Professor Peacock, from Leeds, said: "It's immensely exciting to discover that reactive minerals such as those made from iron and manganese within the ocean have been instrumental in creating the stable conditions necessary for life to have evolved on Earth."

The lessons learned from a better understanding of the Earth's geochemical processes could be used to harness new approaches to tackling modern-day climate change.

Dr James Bradley, an environmental scientist at Queen Mary University of London and one of the authors of the paper, said: "Understanding the complex processes affecting the fate of organic carbon that is deposited on the seafloor is crucial to pinpointing how Earth's climate changes in response to both natural processes and human activity, and helping humanity better manage climate change, since the application and long-term success of carbon capture technologies relies on carbon being locked away in stable forms rather than being transformed into carbon dioxide."

Sustainable mobility planning supported by doughnut thinking

 A new scientific article, carried out in collaboration between Finnish and international researchers, shows how the doughnut model, which examines the overall sustainability of societies, can be applied to transport.

Transport and mobility produce a significant part of cities' carbon emissions and other environmental burdens, but at the same time enable the satisfaction of many basic needs, from going to work to meeting friends. A new scientific article, carried out in collaboration between Finnish and international researchers, shows how the doughnut model, which examines the overall sustainability of societies, can be applied to transport.

The new research focuses on promoting ways to understand and measure the accessibility of areas. Accessibility has become an integral part of the toolbox of urban and transport planners and a flourishing field of research.

"The central idea of the doughnut model developed by the economist Kate Raworth is to provide the basic conditions for a good life for everyone without exceeding the critical boundaries of the environment," says postdoctoral researcher Elias Willberg from the Department of Geography, who led the research.

"We propose that this idea should also be applied in the transport sector, where reducing emissions has long been difficult. You only have to look at the current extreme weather around the world to notice that there is a great and urgent need for a change in ways of thinking and acting," he continues.

The study published in Transport Reviews was led by Finnish researchers from the Digital Geography Lab of the University of Helsinki and Aalto University.

Too narrow metrics one of the most central challenges

However, social and environmental concerns are often treated separately in accessibility research. This easily leads to recommendations that consider only of the perspectives. "For example, it is often most effective to improve accessibility by investing in private cars, which increases an unsustainable load on the environment. On the other hand, if social dimensions are not taken into account in the promotion of sustainable transport modes including walking and cycling, it is easy to end up only to improve the mobility opportunities of the well-off," Willberg continues.

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"Accessibility is still largely measured by only taking into account the travel time," says Aalto University assistant professor Henrikki Tenkanen.

"At the same time, the wider effects on the environment and people remain invisible in our measurements. Fortunately, the rapid development of geospatial data and tools has offered more opportunities to bringing these hidden costs to light, and we aim to advance this work."

How to improve accessibility while simultaneously reducing emissions

The contradictions related to the fairness of the sustainability transition are increasingly visible in the societal debate around transport. Transport emission reduction measures arouse heated emotions and opposition, especially in areas where the accessibility by other means than car is poor.

"The spatial accessibility can be improved in many different ways, but sometimes environmental and social goals inevitably conflict with each other," says Professor Tuuli Toivonen, leader of the Digital Geography Lab at the University of Helsinki. Because of this, planners and decision-makers must have ways to find out whether it is possible to improve accessibility while simultaneously reducing emissions and how it could be done.

"We show that accessibility research is capable of providing even better information and metrics to support this discussion. The key is that knowledge and know-how accumulating from this research are made available to society with open tools and data" she concludes.

Study highlights importance of mineral iron in ocean ecosystems

 New research published today in Nature has revealed the importance of mineral forms of iron in regulating the cycling of this bio-essential nutrient in the ocean.

The findings pave the way for new work on the relationship between the iron and carbon cycles and how changing ocean oxygen levels may interact.

The study, led by the University of Liverpool and involving collaborators in the United States, Australia and France, addresses a knowledge gap in ocean research.

Principal Investigator Professor Alessandro Tagliabue said: "To date we have not fully appreciated the role that mineral forms of iron have played in driving the distributions and temporal dynamics of iron in the ocean"

The ocean of the early earth was low in oxygen and rich in iron, which was incorporated as a catalyst in many biological reactions. These include photosynthesis, which via its proliferation oxygenated the earth system. As iron is less soluble in well oxygenated seawater, precipitation and sinking of iron oxides led to iron levels declining. Consequently, iron now plays a critical role in regulating ocean productivity and hence ecosystems across the contemporary ocean.

It is thought that iron levels are largely regulated above their soluble thresholds by organic molecules called ligands, which bind iron. This view has underpinned the representation of the marine iron cycle in global models used to explore how changes in climate affect levels of biological productivity in the future.

However, oceanographers have been puzzled as to why there seemed to be a much larger loss of iron due to insolubility from the ocean than expected from the measured high levels of ligands. The ocean models built according to the expected pattern have generally performed poorly in reproducing observations.

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This project, which was a process study contribution to the international GEOTRACES effort  was jointly funded by the US National Science Foundation and the UK Natural Environment Research Council and examined the processes driving the cycling of iron over an annual cycle for the first time.

It revealed that iron was largely cycling independently of ligands in the upper ocean and instead controlled by the clustering of iron oxide colloids to form so-called 'authigenic' particles that are lost from the upper ocean.

The authors developed a new numerical model to both explain their results and extrapolate their findings across the ocean. The new model performed markedly better in reproducing other independent observations and highlighted that this new process was important in around 40% of upper ocean waters.

A key implication is that this process occurs via the co-aggregation of iron oxides and carbon, which has implications for the global carbon cycle and may be sensitive to future trends of ocean oxygen loss.

"These findings will cause us to reassess our understanding of the iron cycle and its sensitivity to changing environmental conditions," said Professor Tagliabue.

The University of Liverpool-led study also involved researchers from the University of South Florida, Oregon State University, Bigelow Laboratory for Ocean Sciences, Sorbonne Université, University of Tasmania, University of Leeds, the Bermuda Institute of Ocean Sciences, University of Georgia, and Old Dominion University.

Professor Tagliabue said: "Our work was only possible thanks to the efforts to measure multiple different forms of iron in seawater over the annual cycle at the Bermuda Atlantic Time Series site."

Past climate warming driven by hydrothermal vents

 An international drilling expedition off the Norwegian coast led by Christian Berndt, Professor of Marine Geophysics at GEOMAR Helmholtz Centre for Ocean Research in Kiel, and Sverre Planke, Professor of Marine Geophysics at the University of Oslo, confirms the theory that methane emissions from hydrothermal vents were responsible for global warming about 55 million years ago. The study, published today in the journal Nature Geoscience, shows that the vents were active in very shallow water depth or even above sea level, which would have allowed much larger amounts of methane to enter the atmosphere.

About 55 million years ago, the Atlantic Ocean was born. Until then, Europe and America were connected. As the continents began to move apart, the Earth's crust between them ruptured, releasing large volumes of magma. This rift volcanism has led to the formation of large igneous provinces (LIPs) in several places around the world. One such LIP was formed between Greenland and Europe and now lies several kilometres below the ocean surface. An international drilling campaign led by Christian Berndt from the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, and Sverre Planke from the University of Oslo, Norway, has collected extensive sample material from the LIP, which has now been evaluated.

In their study, published today in the journal Nature Geoscience, the researchers can show that hydrothermal vents were active at very shallow depths or even above sea level, which would have allowed much larger quantities of greenhouse gases to enter the atmosphere than previously thought.

"At the Paleocene-Eocene boundary, some of the most powerful volcanic eruptions in Earth's history took place over a period of more than a million years," says Christian Berndt. According to current knowledge, this volcanism warmed the world's climate by at least five degrees Celsius and caused a mass extinction -- the last dramatic global warming before our time, known as the Paleocene-Eocene Thermal Maximum (PETM). Geologists have not yet been able to explain why, as most modern volcanic eruptions cause cooling by releasing aerosols into the stratosphere.

Further studies of the Karoo large igneous province in South Africa revealed an abundance of hydrothermal vents associated with magmatic intrusions into the sedimentary basin. This observation among others led to the hypothesis that large amounts of the greenhouse gases carbon dioxide and methane could have entered the atmosphere through hydrothermal venting. "When our Norwegian colleagues Henrik Svensen and Sverre Planke published their results in 2004, we would have loved to set off immediately to test the hypothesis by drilling the ancient vent systems around the North Atlantic," says Christian Berndt. But it wasn't that easy: "Our proposal was well received by the Integrated Ocean Drilling Program (IODP), but it was never scheduled because it required riser drilling, a technology that was not available to us at the time."

As the research progressed hydrothermal vent systems were discovered that were within reach of riserless drilling. Thus, the drilling proposal was resubmitted, and the expedition could finally begin in autumn 2021 -- 17 years after the first proposal was submitted.

Around 30 scientists from 12 nations took part in the IODP (now the International Ocean Discovery Program) research cruise to the Vøring Plateau off the Norwegian coast on board the scientific drilling ship "JOIDES Resolution." Five of the 20 boreholes were drilled directly into one of the thousands of hydrothermal vents. The cores obtained can be read by scientists like a diary of the Earth's history. The results were compelling.

The authors show that the vent was active just before the Paleocene Eocene Thermal Maximum and that the resulting crater was filled in a very short time, just as the global warming began. Quite unexpectedly, their data also show that the vent was active in a very shallow water depth of probably less than 100 metres. This has far-reaching consequences for the potential impact on the climate. Christian Berndt: "Most of the methane that enters the water column from active deep-sea hydrothermal vents today is quickly converted into carbon dioxide, a much less potent greenhouse gas. Since the vent we studied is located in the middle of the rift valley, where the water depth should be greatest, we assume that other vents were also in shallow water or even above sea level, which would have allowed much larger amounts of greenhouse gases to enter the atmosphere."

As far as today's climate warming is concerned, there are some interesting conclusions to be drawn from the cores. On the one hand, they do not confirm that the global warming at that time was caused by the dissolution og gas hyrates -- a danger that has been much discussed in recent years. On the other hand, they show that it took many millennia for the climate to cool down again. So the Earth system was thus able to regulate itself, but not on time scales relevant to today's climate crisis.

Picturing where wildlands and people meet at a global scale

 Researchers led by a team at the University of Wisconsin-Madison have created the first tool to map and visualize the areas where human settlements and nature meet on a global scale. The tool, which was part of a study recently published in Nature, could improve responses to environmental conflicts like wildfires, the spread of zoonotic diseases and loss of ecosystem biodiversity.

These areas where people and wildlands meet are called the wildland-urban interface, or WUI for short. More technically, a WUI (pronounced "woo-ee") describes anywhere that has at least one house per 40 acres and is also 50% covered by wildland vegetation such as trees, shrubland, grassland, herbaceous wetland, mangroves, moss and lichen.

Franz Schug, a postdoctoral researcher in the Department of Forest and Wildlife Ecology at UW-Madison, explains that the areas were initially used by the U.S. Forest Service to assist with wildfire management in the Western United States.

Areas defined as WUI cover only about 4.7% of land on Earth, but about half of the human population lives within them. Many people enjoy living in these places because they like to be near the amenities of nature, explains Volker Radeloff, a professor of forest and wildlife ecology at UW-Madison.

"It reflects an affinity of people to nature, which is a good thing. If people said in general, 'No, we rather not be anywhere near a forest,' I'd be more worried with that," Radeloff says.

But these areas are also hot spots for environmental conflicts like wildfires, the spread of diseases from animals, habitat fragmentation and loss of biodiversity. While climate change is projected to increase the potential environmental conflict in the WUI, population growth increases the frequency in which humans and wildlands come into contact in many places. Knowing where both is likely to happen globally is important for planning for the future.

Yet, the WUI has only been prominently described in the United States and a few other developed countries. Schug saw a gap in the research. He set out to investigate WUIs' worldwide distribution, though mapping the high-resolution, global view required him to wrangle and make sense of a lot of information.

"I think the greatest challenge is just the amount of data that went into this," he says. "We have two servers in the basement [of the lab building] that were reactivated for that purpose. I think the whole thing covers several terabytes of data processing."

After setting up the computer program, it took three months to run through all the data, flagging the regions that qualify as a WUI. The land cover and building data they fed the computer was sourced from publicly available databases and stored on large servers.

Schug was able to record previously undocumented WUI in eastern Asia, East Africa and parts of South America.

Unsurprisingly, WUI around the world don't all look the same or have the same kinds of ecosystems. If the goal is to be able to inform better management practices, Schug realized he would need to provide more context on what the kinds landscapes made up these WUIs. After all, managing rain forests is very different from managing grasslands.

"Especially in these biomes, where other studies predict that most likely climate change will have an impact on fire severity and fire frequencies, where a lot of people live, they're definitely areas that will be a future interest," Schug says.

The WUI is already being leveraged in countries like Poland, Argentina and Portugal, but Radeloff and Schug see this global view as a tool that can help land managers around the world know where they need to keep an eye on in the future.

As the climate changes, some of these biomes will see more wildfires, more people and animals coming into contact with each other for the first time and more opportunities for the spread of disease and ecosystem disruption.

Schug hopes this work will inspire further regionalized research around the WUIs they've documented, empowering local land managers to better prepare for change.