Climate change is intensifying extremes also in the oceans

Anthropogenic climate change is becoming increasingly noticeable, in Switzerland most recently during the summer of 2021, which was marked by heavy rains and flooding. It has long been known that global warming is causing not only longer and more intense heatwaves, but also, depending on the region, more severe droughts, rains and storms. Moreover, these kinds of extreme weather events increasingly occur in combination, compounding each other.

However, there has been little research into how extreme events develop in the world's oceans. Beginning in the early 2000s, first scientific studies pointed out the significance of marine heatwaves and their impact on ecosystems. A wake-up call came in 2011 in the form of a persistent marine heatwave off the west coast of Australia that destroyed the species-rich kelp forests there. Probably the most prominent example of a marine heatwave is the "Blob," as it is known -- a giant bubble of warm water that spread in the northeast Pacific Ocean and along the US West Coast from Alaska to the equator from 2013 to 2015. It killed millions of marine birds, fish and other creatures.

Researchers at ETH Zurich, the University of Bern and the University of Tasmania used a high-resolution ocean model to analyse this extreme weather event from a new perspective. Led by Nicolas Gruber, Professor of Environmental Physics at ETH Zurich, the international team concluded that it was not solely the high water temperatures that caused the mass die-off, but probably a combination of extreme events that occurred simultaneously.

A combination of extreme events is particularly dangerous

The researchers used their model to reconstruct the Blob's development over time, and in doing so, they analysed for the first time the combination of temperature, acidity and oxygen concentration of the ocean water. Their simulations show that, at the peak of the heatwave in July 2015, extremes in acidity and low oxygen had also spread extensively throughout the affected region in the northeast Pacific.

From this, the ETH researchers concluded that what occurred off the coasts of Oregon, Washington and British Columbia was not merely a heatwave but a compound extreme event. "When marine life is confronted with multiple stressors at once, it has difficulty acclimatising," Gruber says. "For a fish species that's already living at the upper end of its optimal temperature range, an added oxygen deficiency can mean death."

That's why, in their study -- which was just published in the journal Nature -- the researchers called on the scientific community to pay greater attention to compound extreme events in the ocean. "To assess the risks of these kinds of events, we urgently need to study the chain of different environmental factors leading to such extremes more closely -- and not only in individual regions, but also at the global level," Gruber says.

Global distribution analysed for the first time

The authors of this study have already taken a first step in this direction. In addition to the Blob, they used a global climate model to investigate where and how often extreme events -- separated into heatwaves and situations involving anomalously high acidity and low oxygen -- occur and how severe they are.

To demonstrate the impact of climate change, the researchers simulated the extreme events for the period from 1861 to 2020 and compared the current situation with pre-industrial times. The results speak for themselves: globally, the number of hot days on the ocean surface each year has increased tenfold, from around 4 days to 40. The number of days on which the ocean depths are characterized by anomalously low oxygen has increased fivefold.

With regard to acidity extremes, the situation is even graver. Compared with pre-industrial times, what has now established itself is almost a permanent extreme situation. "This shows how far climate change has already advanced in the ocean," says Thomas Frölicher, Professor at the University of Bern and co-author of the study.

The researchers also show on a world map which ocean regions see the most intense extreme events -- both at the ocean surface and 200 metres below it. The spatial resolution of these events within the water column is important because this further limits the possibilities for the affected marine life to escape, as the study's authors highlight.

Huge knowledge gaps

The researchers cannot assess the ecological consequences of extreme events in detail, but one thing is clear: compared with climate change, which progresses slowly, the effect of extremes on ocean life is generally stronger. The sudden occurrence of environmental changes makes many kinds of adaptation strategies impossible.

Current model simulations can replicate the response of these ecosystems to extremes only to a limited extent -- they cannot yet do justice to the complexity of biological and ecological processes. "For example, our models are still extremely limited in their ability to distinguish between different groups of algae and zooplankton," says Meike Vogt, a senior researcher in Gruber's group. But this differentiation is important, as different species differ greatly in their ability to withstand extremes.

"We know from Swiss forests that beech trees are less drought-tolerant than, for instance, pines," Gruber says. By contrast, far too little is known at present about the marine ecosystems. "We lack broad understanding of the ecosystem structure and function in the various ocean regions. Only when we have this foundation will we be able determine the impact of climate change and extremes," Vogt says.

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Map of transparent butterflies highlights biodiversity hotspot in the Andes Mountains

With over a million known species, insects are by far the most diverse group of organisms on Earth, with conservative estimates indicating there are millions more waiting to be found. But extinction due to human pressures may be outpacing the rate of discovery, with species disappearing before researchers even knew they existed.

To conserve these species, scientists must first know where they are. While the distributions of some plant and animal groups have been extensively mapped, comparatively little is known regarding the whereabouts of the world's insects.

In a new study, researchers created the most detailed distribution map to date of butterflies in the American tropics, showing that areas of highest diversity coincide with regions most threatened by deforestation and development. The study specifically focused on Ithomiini, or glasswing butterflies, a large group with nearly 400 species that occur throughout much of Central and South America. Their ubiquity may make them a good indicator for the fate of other insects in the region.

"If we want to understand the diversity of insects in general, then one approach is to concentrate on groups that likely reflect the diversity of all insects and for which we have good knowledge, like butterflies," said study co-author Keith Willmott, curator and director of the Florida Museum of Natural History's McGuire Center for Lepidoptera and Biodiversity.

Mimicry both helps and hinders glasswings

Glasswing butterflies get their namesake from their unusual, transparent wings marked with colorful spots of alternating hues and patterns. As with many other butterfly species, such as monarchs, these markings serve as a warning. Male glasswing butterflies feed on the nectar and tissue of poisonous plants, concentrating the toxins in their abdomen and passing them on to females when mating. These toxins, a type of alkaloid, give the butterflies and their eggs a bitter taste that makes them unpalatable.

But would-be predators aren't born innately knowing not to eat these butterflies, instead learning through trial and error. As a result, many glasswing species have evolved similar wing patterns that give them strength in numbers.

"Since different species share the same warning color patterns, they share the overall cost per species of educating predators to avoid them," Willmott said.

This type of resemblance, called Müllerian mimicry, has helped glasswing butterflies survive and diversify in the varied habitats of the tropics, but it also comes at a cost. While this strategy is effective when all species resembling one another are thriving, the extinction of any one species could jeopardize the survival of others, Willmott explained. "This is particularly true if one of the more common species goes extinct, because all the others lose the benefit they gained from being involved in Müllerian mimicry with those butterflies."

Glasswing butterflies are most diverse and most vulnerable at high elevations

Willmott and his colleagues have spent the last several decades trekking across mountains and forests in search of glasswings, describing new species and documenting their natural history along the way. By combining the data they've collected over the years with information gleaned from specimens in more than 60 museums and private collections, the researchers compiled nearly 30,000 distribution records. They used this extensive dataset to map the diversity of glasswings and the interactions between lookalike species throughout the American tropics.

Their results indicate glasswings are highly diverse in particular parts of their range, including the Amazon River basin, where their transparent wings help them blend in against the backdrop of forest gloom. But the majority of species cluster together in mountainous biodiversity hotspots. The eastern slopes of the Andes Mountains contained the top 5% of glasswing diversity, while secondary hotspots included the highlands of Central America and the Atlantic coastal forest of Brazil.

While large tracts of the Amazon rainforest remain relatively undisturbed, glasswing diversity in the tropical Andes frequently overlapped with areas at the highest risk of habitat loss due to land conversion for agriculture. This was especially true for species with restricted distributions, highlighting the pressing need for conservation efforts in these areas.

Mountainous regions create a variety of small, localized environments as they climb in elevation. The relatively young Andes, which are among the world's highest mountains, support a correspondingly large number of species. The differences in topography, temperature and rainfall also make the Andes an ideal place to grow a variety of crops. "At the moment, loss of habitat is the most significant threat," Willmott said. "It is just an unfortunate coincidence that areas that are good for people to live are also areas that support high animal and plant diversity."

Lead author Maël Doré, a doctoral student at the National Museum of Natural History in Paris, also worries that climate change may further limit the range of already restricted species on the slopes of tropical mountains. As temperatures increase, species may cope by shifting their distributions to higher elevations, but whether glasswing communities will move fast enough to keep up with climate change is uncertain.

Far from the Andes, the lower and older mountains along the Brazilian Atlantic coast are home to a number of rare and endemic glasswing species, which also face threats from habitat destruction. "This region has experienced almost five centuries of human occupation, but it was also here that pioneering initiatives to protect Neotropical butterflies and their habitats were born almost 100 years ago," said co-author André Freitas, a professor at the Universidade de Campinas in São Paulo, Brazil.

Still, Willmott and his colleagues remain optimistic. With a detailed map of where butterflies occur, conservation efforts can be directed to preserve environments and communities under threat, as well as those that are still untouched by humans.

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Deep mantle krypton reveals Earth’s outer solar system ancestry

Krypton from the Earth's mantle, collected from geologic hot spots in Iceland and the Galapagos Islands, reveals a clearer picture of how our planet formed, according to new research from the University of California, Davis.

The different isotopes of krypton are chemical fingerprints for scientists sleuthing out the ingredients that made the Earth, such as solar wind particles and meteorites from the inner and outer solar system. The findings indicate Earth's volatile elements -- essentials such as carbon, water and nitrogen -- arrived as Earth was growing and becoming a planet. This contradicts the popular theory that Earth's volatile elements were mostly delivered near the end of Earth's formation, which is marked by the moon-forming giant impact. Instead, the krypton isotopes suggest planetesimals from the cold outer solar system bombarded the Earth early on, millions of years before the big crunch. The young Earth also hoovered up dust and gas from the solar nebula (the cloud surrounding the sun) and was bombarded by meteorites.

"Our results require concurrent delivery of volatiles from multiple sources very early in Earth's formation," said Sandrine Péron, the lead author of the study. Péron, currently a Marie Sk?odowska-Curie Actions Fellow at ETH Zürich in Switzerland, conducted the research at UC Davis as a postdoctoral fellow working with Professor Sujoy Mukhopadhyay in the Department of Earth and Planetary Sciences.

"This study provides clues for the sources and timing of volatile accretion on Earth, and will help researchers better understand how not only Earth formed, but also other planets in the solar system and around other stars," Péron said. The study is published Dec. 15 in the journal Nature.

Primordial geochemistry

The volcanic hot spots spewing lava in Iceland and the Galapagos are fed by slushy magma plumes rising from the deepest layer of the mantle, near its boundary with the Earth's iron core. The elements and minerals in this deep layer are relatively unchanged since before the moon-forming impact, like a time capsule of the early Earth's chemistry more than 4.4 billion years old.

Mukhopadhyay's lab specializes in making precise measurements of noble gases in rocks from Earth and elsewhere. To sample deep mantle krypton, the researchers collected lava at hot spot plumes. The ancient gases rise to the surface in the erupting lava, getting trapped and entombed as bubbles in a glassy matrix when the lava quenches to a solid, providing some protection from outside contamination. However, even the most abundant krypton isotopes in these bubbles amounts to only a few hundred million atoms, making their detection challenging, Mukhopadhyay said.

Péron designed a new technique for measuring mantle krypton with mass spectrometry, concentrating krypton from rock samples in an environment virtually free of air contamination and neatly separating it from argon and xenon.

"Ours is the first study to precisely measure all krypton isotopes for the mantle, including the rarest krypton isotopes, Kr-78 and Kr-80," she said.

Building a planet

The researchers discovered that the chemical fingerprint of deep mantle krypton closely resembled primitive, carbon-rich meteorites, which may have been delivered from the cold, outer reaches of the solar system. But previous work by Mukhopadhyay and others found that neon, another noble gas in the deep mantle, was derived from the sun. The two different results suggest at least two distinct volatile sources for the Earth's mantle, delivered very early in its history. The researchers also noted less of the rare isotope Kr-86 in the deep mantle compared to known meteorites. The deficit in Kr-86 suggests that known meteorites alone may not account for all the mantle's krypton.

Finally, the new results also have implications for how Earth's atmosphere arose. The ratio of different krypton isotopes in the deep mantle doesn't match the isotope ratio in Earth's atmosphere, the researchers found. This means some gases in the atmosphere, including noble gases like krypton, were delivered to Earth after the moon-forming impact. Otherwise, Earth's mantle and atmosphere would have the same isotopic composition due to isotopic equilibration following the impact, Péron said.

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Theropod dinosaur jaws became stronger as they evolved

Theropod dinosaurs evolved more robust jaws through time allowing them to consume tougher food, a new study reveals.

Researchers used digital modelling and computer simulation to uncover a common trend of jaw strengthening in theropods -- expanding the rear jaw portion in all groups, as well as evolving an upturned jaw in carnivores and a downturned jaw in herbivores.

Publishing their findings today in Current Biology, scientistsrevealed that biomechanical analysis showed these form changes made jaws mechanically more stable when biting -- minimising the chance of bone fracture.

The international team, led by scientists at the University of Birmingham, created digital models of more than 40 lower jaws from five different theropod dinosaur groups, including typical carnivores like Tyrannosaurus and Velociraptor, and lesser-known herbivores like ornithomimosaurs, therizinosaurs and oviraptorosaurs.

Fion Waisum Ma, PhD researcher at the University of Birmingham, who led the study, said: "Although theropod dinosaurs are always depicted as fearsome predators in popular culture, they are in fact very diverse in terms of diets. It is interesting to observe the jaws becoming structurally stronger over time, in both carnivores and herbivores. This gives them the capacity to exploit a wider range of food items.

"Theropod dinosaurs underwent extreme dietary changes during their evolutionary history of 165 million years. They started off as carnivores, later on evolved into more specialised carnivores, omnivores and herbivores. Studying how their feeding mechanics changed is key to understanding the dietary transitions in other vertebrate animals too."

For example, in carnivores like tyrannosauroids, an early form like Guanlong had a relatively slender and straight jaw. But later forms such as Tarbosaurus and Tyrannosaurus evolved deeper jaws with the front portion bending upward, which increase jaw strength.

Having a strengthened jaw is especially important to herbivorous theropods, as their jaws experience considerable stress from repetitive plant cropping. Herbivores like Erlikosaurus and Caudipteryx have extremely downward-bending jaws that could help dissipate such stress.

Dr Stephan Lautenschlager, Senior Lecturer at the University of Birmingham and senior author of the study, said: "It is fascinating to see how theropod dinosaurs had evolved different strategies to increase jaw stability depending on their diet. This was achieved through bone remodelling -- a mechanism where bone is deposited in regions of the jaw that experience high stresses during feeding."

The researchers studied the feeding mechanics of tyrannosaurids through growth and observed that the deeper and more upturned jaws of adult theropods, such as Tyrannosaurus and Tarbosaurus, are structurally stronger compared to those of their juvenile forms.

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Soils in old-growth treetops can store more carbon than soils under our feet

New research reveals a previously underappreciated way old-growth forests have been recycling and storing carbon: treetop soils. Branches in forest canopies can hold caches of soil that may store substantially more carbon than soils on the ground beneath them, and scientists are just beginning to understand how much carbon canopy soils -- which exist on every continent except Antarctica -- could store.

The new research on these unique soils, being presented on Wednesday, 15 December at AGU Fall Meeting 2021, marks the first attempt to quantify carbon capture by canopy soils. The work highlights another way old-growth forests are rich, complex ecosystems that cannot be quickly replaced by replanting forests.

Tree branches collect fallen tree leaves and other organic material over hundreds of years, like the ground does. On top of the branches, the plant litter decomposes as it accumulates, forming a carbon-rich layer that can be several inches thick. The researchers climbed up into the rainforest canopy in Costa Rica, instruments in hand, to find out just how much carbon canopy soils can contain.

Active carbon, a short-term storage pool of organic carbon, was three times higher in canopy soil compared to soils underfoot, the researchers found.

"We knew these would be really organic-rich soils, but we didn't expect the extremely large amount of carbon compared to mineral soils," said Hannah Connuck, an undergraduate researcher at Franklin and Marshall College who will be presenting the study results.

The researchers are still calculating the total concentration of organic carbon at their research site, but other research has found canopy soils to have up to 10 times higher concentrations of organic carbon, according to soil scientist Peyton Smith, a study co-author and Connuck's soil science mentor at Texas A&M University.

Connuck and Smith also measured how much carbon dioxide was being released by microbial organisms living in the canopy soils, which is critical for knowing whether soils are storing or releasing carbon overall. They found that even though the microbes were releasing higher volumes of carbon dioxide than ground soils, their rate of carbon storage was rapid enough to compensate, likely making canopy soils a net carbon sink that has not been considered in carbon models yet.

"It could be a substantial carbon sink, and we need to account for it," Smith said.

Like other soils, canopy soils take a long time to form, and therefore take a long time for a forest to recover if an area of old growth is cut down. The soils also host unique microbiomes, including highly diverse microbial organisms and canopy-specific plants like epiphytic orchids.

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Breakthrough in using CRISPR-Cas9 to target fat cells

Fat -- it is vital for life but too much can lead to a host of health problems. Studying how fat, or adipose, tissue functions in the body is critical for understanding obesity and other issues, yet structural differences in fat cells and their distribution throughout the body make doing so challenging.

"Fat cells are different from other cells in that they lack unique cell surface receptors and only account for a minority of the cells within fat tissue," said Steven Romanelli, Ph.D., a former member in the laboratory of Ormand MacDougald, Ph.D., in the Department of Molecular & Integrative Physiology.

In a new paper published in the Journal of Biological Chemistry, Romanelli, MacDougald and their colleagues describe a breakthrough using CRISPR-Cas9, a tool that has transformed molecular biological research, but whose use in the study of adipose tissue had been elusive.

"The biggest challenge in terms of adipose research to date has been that if you want to study a gene's function, you have to commit a considerable amount of time, resources and money into developing a transgenic mouse," said Romanelli.

The traditional way of developing mouse models involves breeding mice with a desired mutation to delete or introduce certain genes of interest, which Romanelli says can take more than a year and tens of thousands of dollars.

CRISPR-Cas9 has revolutionized this process. It's a gene editing technique comprised of an enzyme called Cas9 which can break strands of DNA and a piece of RNA that guides the Cas9 enzyme to a specific site in the genome for editing. This tool is packaged into a non-harmful virus for delivery to the cells being studied. The tool has been successfully used to study heart, liver, neurons, and skin cells to name a few, but never a certain type of adipose cells known as brown fat.

Using the technique, the team was able to successfully target brown fat, a specialized adipose tissue used to generate heat and protect core body temperature.

"What we've been able to do is take that whole process and distill it into anywhere from two weeks to a month to generate a transgenic mouse, reducing the cost to less than $2,000. Not only does it reduce time and cost, it democratizes the research so that any lab that is familiar with molecular biology techniques can adopt this method and do it themselves," said Romanelli.

They were also able to use this method to delete multiple genes simultaneously, a fact that could help researchers better understand important molecular pathways.

Using their adeno-associated virus CRISPR-Cas9 components, they were able to knockout the UCP1 gene that defines brown adipose and enables it to generate heat, in adult mice. They observed that the knockout mice were able to adapt to the loss of the gene and maintain their body temperature in cold conditions, hinting at other pathways involved in temperature homeostasis.

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Advanced analysis of Apollo sample illuminates Moon’s evolution

Sophisticated analysis of a rock sample taken from the Moon during the Apollo 17 mission revealed new information about the complex cooling and evolutionary history of the Moon. The findings, from University of Hawai'i (UH) at Manoa researchers, were published today in Nature Communications.

Apollo 17 astronauts collected the rock sample troctolite 76535 from the Moon's surface in 1972, and it remains one of the most scientifically valuable samples of the Moon due to its pristine nature. Further, the rock type is widespread on the Moon and likely contains important clues to understanding lunar formation.

William Nelson, lead author of the study and Earth Sciences graduate student in the UH Manoa School of Ocean and Earth Science and Technology (SOEST), and co-authors used a specialized electron microprobe to perform high-resolution analysis of troctolite 76535.

"Previous reports suggest the minerals in the Apollo 17 sample were chemically homogeneous," said Nelson. "Surprisingly, we found chemical variations within crystals of olivine and plagioclase. These heterogeneities allow us to constrain the earliest, high-temperature cooling histories of these minerals using numerical models."

SOEST researchers used the UH High-Performance Computing facilities, Mana, to consider the effects of a variety of computer-simulated cooling paths -- well over 5 million chemical diffusion models.

"The simulations revealed that these heterogeneities could only survive a relatively short period of time at high temperatures," said Nelson.

The diffusion patterns preserved in the mineral grains and observed with the microprobe were consistent with a rapid cooling history of no more than 20-million-years at high temperatures. The finding challenges previous estimates of a 100-million-year cooling duration and supports initial rapid cooling of magmas within the lunar crust.

"This is changing our outlook on how an important suite of lunar rocks formed," said Nelson.

To reconcile high-temperature cooling rates with the generally accepted view of the way in which these rocks formed, the research team proposed that perhaps this rock type is formed by a process called reactive infiltration wherein a melt interacts with rock -- changing its chemical and physical makeup.

The study also demonstrates the value of re-examining previously analyzed samples using modern techniques and how quickly new data can reshape our understanding of planetary evolution.

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Concurrent heatwaves seven times more frequent than in 1980s

Multiple large heatwaves the size of Mongolia occurred at the same time nearly every day during the warm seasons of the 2010s across the Northern Hemisphere, according to a study led by Washington State University researchers.

Using climate data from 1979 to 2019, the researchers found that the number of heatwaves occurring simultaneously in the mid- to high-latitudes of the Northern Hemisphere was seven times greater in the 2010s than in the 1980s. On average, there were concurrent heatwaves on 143 days each year of the 2010s -- almost every day of the 153 days of the warm months of May through September.

The concurrent heat events also grew hotter and larger: their intensity rose by 17% and their geographic extent increased 46%.

"More than one heatwave occurring at the same time often has worse societal impacts than a single event," said Cassandra Rogers, a WSU post-doctoral researcher and lead author of the study in Journal of Climate. "If certain regions are dependent on one another, for instance for agriculture or trade, and they're both undergoing stresses at the same time, they may not be able to respond to both events."

Heatwaves can cause disasters from crop failures to wildfires. Concurrent heatwaves can multiply those threats, the authors pointed out, exhausting the ability of countries to provide mutual aid in crises as was seen during the multiple wildfires in the U.S., Canada and Australia associated with the 2019 and 2020 heatwaves. A previous study also found that concurrent heatwaves caused about a 4% drop in global crop production.

This study defined large heatwaves as high temperature events lasting three days or more and covering at least 1.6 million square kilometers (about 620,000 square miles), which is roughly equivalent to the size of Mongolia or Iran.

The researchers analyzed ERA5 data produced by the European Center for Medium-Range Weather Forecasts, which blends vast amounts of observational data from weather stations on land, water buoys and aircraft as well as data from satellites with weather forecasting models. ERA5 provides globally complete estimates of hourly data for various climate variables from 1979, when satellite data became available, which is why the study focused on this time period.

Using these observational data, the researchers found that the primary driver of the heatwaves was the overall rise in global mean temperature due to climate change. The world has warmed 1 degree Celsius (about 1.8 degrees Fahrenheit) over the last century with the vast majority of the rise, two-thirds, occurring since 1975. The researchers also found that increasing occurrence of two hemisphere-wide circulation patterns made particular areas more vulnerable to concurrent heatwaves, including eastern North America, eastern and northern Europe, East Asia and eastern Siberia.

The study adds more evidence for the need to curb greenhouse gas emissions and mitigate climate change, the researchers said, and the continued rise in temperature means the world should prepare for more concurrent heatwaves.

"As a society, we are not currently adapted to the types of climate events we're experiencing right now," said co-author Deepti Singh, WSU associate professor in the School of the Environment.

"It's important to understand how we can reduce our vulnerability and adapt our systems to be more resilient to these kind of heat events that have cascading societal impacts."

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Brain study on how to slow down climate change

When it comes to climate-friendly behaviour, there is often a gap between what we want and what we actually do. Although most people want to see climate change slowed down, many do not behave in an appropriately sustainable way. Researchers at the University of Bern have now used brain stimulation to demonstrate that the ability to sympathize with the future victims of climate change encourages sustainable behaviour.

Global climate change may be the biggest challenge faced by humanity today. Despite decades of warnings and political resolutions, however, sustainability remains a long way from being achieved. "The fact that people aren't acting in a more climate friendly way isn't because we know too little about this critical situation, though." explains Daria Knoch, Professor for Social Neuroscience at the University of Bern. To find out more about the reasons that prevent us from acting sustainably, Daria Knoch and her team have conducted a neuroscientific study. The findings have just been published in the international journal Cortex.

While some effects of global warming are already visible today, those affected more strongly will be people in the future who we do not know. "It is precisely our inability to mentalise with these strangers that discourages climate-friendly action," says Daria Knoch, commenting on the findings of the new study that she carried out with her research group in the "Social Neuro Lab" at the University of Bern. During the study, participants received stimulation to a part of their brain which plays an important role for taking the perspective of others. This stimulation led to more sustainable behaviour.

Stimulation of the part of the brain responsible for forming perspectives

During the experiment, participants in groups of four withdrew real money from a shared pool. Each participant decided for themself: the more money they withdrew from the pool, the more they ultimately had in their pocket. However, if the group of four withdrew too much money overall, this had consequences for the next group: the payment they received was much lower. Thus, the experiment mimicked a real situation in which the overuse of a resource has negative consequences for other people in the future.

While deciding on the amount of money to withdraw, some participants received a brain stimulation (experimental group): a non-invasive, harmless, mild electrical current was applied to the skull to increase the function of the stimulated brain area. The researchers in Bern stimulated an area which plays a strong role in taking the perspective of others, and discovered that it had a considerable impact: the stimulated individuals made more sustainable decisions than the participants without the stimulation (control group), by deciding not to withdraw an excessive amount of money from the pool.

Benefits for climate communication

"Applying brain stimulation to the general public is out the question, of course," explains Benedikt Langenbach, lead author of the study and a former PhD student at the Social Neuro Lab. However, according to the researchers, the functioning brain area in question can also be enhanced, for example, through neurofeedback and meditation. According to Benedikt Langenbach, who now works at the University of Duisburg-Essen, additional strategies are also available to improve the forming of perspectives: "We know that people are more likely to empathise with someone -- a victim of climate change, for example -- if they are able to identify with them."

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Scientists find new details about how immune system builds long-term memory

Experts in Japan have identified a fundamental part of the immune system's long-term memory, providing a useful new detail in the pursuit to design better vaccines for diseases, ranging from COVID-19 to malaria. The research, published in the Journal of Experimental Medicine, reveals a new role for the enzyme TBK1 in deciding the fate of immune system memory B cells.

The immune system is made of many cell types, but the two types relevant for this University of Tokyo research project are white blood cells called CD4+ follicular helper T cells and B cells. After the body recognizes an infection, the follicular helper T cells release chemical signals that cause immature B cells to learn and remember what pathogens to attack. This process of T-to-B cell signaling and B cell training occurs within a temporary cell structure called the germinal center in organs of the immune system, including the spleen, lymph nodes and tonsils. Memory B cells developed within the germinal center memorize a pathogen the first time it infects you and then if it ever gets into your body again, the mature, trained memory B cells attack it by inducing antibody production before the pathogen can multiply, saving you from feeling sick a second time.

"A goal of vaccination is to produce high-quality memory B cells for long-lasting antibody production," said Project Assistant Professor Michelle S. J. Lee from the UTokyo Institute of Medical Science, first author of the recent publication.

"There are many factors to consider when designing vaccines for long-lasting immunity, so we should not focus only on the germinal center alone. But if you don't have a functional germinal center, then you will be very susceptible to reinfection," said Lee.

However, there is no limit to the number of times you can be bitten by mosquitoes and reinfected by the malaria parasite. Somehow, malaria parasites escape memory B cells. Although children are more likely to die from malaria than adults, some people can become severely ill despite any number of previous malaria infections.

This ability of the parasite to prevent and evade effective B cells is what makes malaria an interesting pathogen for Professor Cevayir Coban, who leads the Division of Malaria Immunology at the UTokyo Institute of Medical Science and is last author of the research paper with Lee and collaborators at Osaka University.

"We want to understand the fundamentals of the natural immune response. Whatever we do should aim to eventually benefit malaria patients," said Coban. "The COVID-19 pandemic brought global attention to infectious diseases and interest in vaccine design, so we have a chance to renew the focus on neglected diseases like malaria," she continued.

Over many years, the scientific community has identified a wide range of roles for the molecule TBK1, an enzyme that can alter the activity of genes or other proteins by adding chemical tags, through a process called phosphorylation. TBK1 has well-known roles in antiviral immunity. However, no research group had connected TBK1 to B cell fate and the germinal center.

Researchers genetically modified mice that had nonfunctional TBK1 genes only in specific types of cells, primarily either B cells or CD4+ T cells. This cell type-specific knockout of TBK1 gives researchers a clearer idea of what a gene with many jobs is doing in different cells of the body. Coban, Lee and their colleagues infected these modified mice and healthy adult mice with the malaria parasite, observed their health, and then examined samples of their spleens and lymph nodes.

Microscopy images revealed that germinal centers only form in mice that have functional TBK1 in their B cells. Mice with no TBK1 in their B cells were more likely to die and died sooner from the malaria infection than their normal peers. Additional experiments showed that the few mice who survived malaria with no TBK1 in their B cells were able to use other types of immune responses, but they can become reinfected.

However, deleting TBK1 only from the CD4+ follicular helper T cells had no effect on the germinal centers or how the mice fared with a malaria infection.

Further analysis confirmed that without TBK1, many proteins in immature B cells had abnormal phosphorylation compared to normal immature B cells. For different genes, abnormal phosphorylation can cause either abnormal increases or decreases in activity. Researchers suspect that in B cells, TBK1 activity acts as an off switch for certain genes, essentially turning off genes that trap the B cells in their immature state.

"This is the first time to show TBK1 is essential in B cells to form the germinal centers and produce high-quality, mature antibodies," said Lee.

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Mystery behind formation of surface ice-shapes on Pluto unraveled

Scientists have unravelled a fascinating new insight into how the landscape of the dwarf-planet Pluto has formed.

A team of international researchers, including Dr Adrien Morison from the University of Exeter, has shown how vast ice forms have been shaped in one of the planet's largest craters, Sputnik Planita.

Perhaps the most striking feature on Pluto's surface, Sputnik Planitia is an impact crater, consisting of a bright plain, slightly larger than France, and filled with nitrogen ice.

For the new study, researchers have used sophisticated modelling techniques to show that these ice forms, polygonal in shape, are formed by the sublimation of ice -- a phenomenon where the solid ice is able to turn into gas without going through a liquid state.

The research team show this sublimation of the nitrogen ice powers convection in the ice layer of Sputnik Planitia by cooling down its surface.

The research is published in the leading journal Nature on Wednesday, December 15th 2021.

Dr Morison, a Research Fellow from Exeter's Physics and Astronomy department said: "When the space probe New Horizon performed the only, to date, fly-by of Pluto in 2015, the collected data was enough to drastically change our understanding of this remote world.

"In particular, it showed that Pluto is still geologically active despite being far away from the Sun and having limited internal energy sources. This included at Sputnik Planitia, where the surface conditions allow the gaseous nitrogen in its atmosphere to coexist with solid nitrogen.

"We know that the surface of the ice exhibits remarkable polygonal features -- formed by thermal convection in the nitrogen ice, constantly organizing and renewing the surface of the ice. However, there remained questions behind just how this process could occur."

In the new study, the research team conducted a series of numerical simulations that showed the cooling from sublimation is able to power convection in a way that is consistent with numerous data coming from New Horizons -- including the size of polygons, amplitude of topography and surface velocities.

It is also consistent with the timescale at which climate models predict sublimation of Sputnik Planitia, beginning around 1 -- 2 million years ago. It showed that the dynamics of this nitrogen ice layer echo those found on Earth's oceans, being driven by the climate.

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Meltwater influences ecosystems in the Arctic Ocean

In the summer months, sea ice from the Arctic drifts through Fram Strait into the Atlantic. Thanks to meltwater, a stable layer forms around the drifting ice atop the salty seawater, producing significant effects on biological processes and marine organisms. In turn, this has an effect on when carbon from the atmosphere is absorbed and stored, as a team of researchers led by the Alfred Wegener Institute has now determined with the aid of the FRAM ocean observation system. Their findings have just been published in the journal Nature Communications.

Oceans are one of the largest carbon sinks on our planet, due in part to the biological carbon pump: just below the water's surface, microorganisms like algae and phytoplankton absorb carbon dioxide from the atmosphere through photosynthesis. When these microorganisms sink to the ocean floor, the carbon they contain can remain intact for several thousand years. As experts from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have now discovered, the meltwater from sea-ice floes can delay this process by four months.

From the summer of 2016 to the summer of 2018, the FRAM (Frontiers in Arctic Marine Monitoring) ocean observation system continually gathered data in Fram Strait (between Greenland and Svalbard). Dense clusters of moorings were installed at two sites in the strait in order to monitor as many aspects of the coupled physical-biological processes in the water as possible. Physical, biogeochemical and acoustic sensors throughout the water column and on the ocean floor, as well as devices that gathered water and sediment samples for subsequent laboratory analysis, were used. "For the first time, for two entire years we were able to comprehensively monitor not only the seasonal developments of microalgae and phytoplankton, but also the complete physical, chemical and biological system in which these developments take place," says Dr Wilken-Jon von Appen, a climate researcher at the AWI and first author of the study.

During this period, the sea-ice export reached two extremes: in the summer of 2017, an extraordinarily large amount of ice was transported out of the Arctic through Fram Strait. This produced a great deal of low-saline meltwater and a pronounced stratification of the water. In contrast, uncharacteristically little ice was transported out of the Arctic in the summer of 2018, which meant there was very little meltwater and therefore no pronounced, salinity-based stratification. The processes involved in the biological carbon pump progressed so differently during these two extremes that the experts refer to them as two different regimes: the meltwater regime (summer of 2017) and the mixed-layer regime (summer of 2018).

Meltwater regime in the summer of 2017

The first algal and phytoplankton blooms appeared on 15 May, when the atmosphere began warming the ocean. In the summer of 2017 a great deal of ice drifted through Fram Strait, producing large quantities of meltwater. "This low-saline water lay atop the saltwater without mixing," says von Appen. "And the stratification between 0 and 30 metres was ten times as intense as between 30 and 55 metres." Consequently, very few nutrients made their way upwards from the deeper water layers, while very little carbon made its way to the seafloor. Phytoplankton growth, which is the first step in the biological carbon pump, took place almost exclusively in the top 30 metres. This intense stratification only collapsed in mid-August, when the atmosphere no longer warmed the water's surface. The majority of the biomass drifted down from the upper layer between September and November, was more than three months old, and was too lacking in nutrients to interest fauna at the ocean floor. In the meltwater regime, during the bloom the microorganisms were able to fix up to 25 grams of carbon per square metre.

Mixed-layer regime in the summer of 2018

The spring and summer of 2018 were another story entirely: conditions were relatively ice-free, which meant less meltwater and less intense stratification of the seawater. A mixed layer formed to a depth of ca. 50 metres. With the first of May came the first diatom blooms; at the same time, the numbers of zooplankton, and of the fish that primarily feed on them, began to rise. Thanks to their faeces, only two to three weeks after the start of the bloom, organic carbon reached depths of up to 1200 metres. Four to seven weeks after the start of the bloom -- almost four months earlier than in the summer of 2017 -- the biomass reached the seafloor. This material was rich in nutrients, attracting five times more fish and benthic fauna than in the meltwater summer. During the bloom, the algae were able to fix roughly 50 grams of carbon per square metre, twice as much as in the meltwater regime.

Despite all these differences between the two regimes, the biological carbon pump wasn't necessarily more productive in the summer of 2018: "We found that, in the summer of 2017, the majority of the organic carbon didn't reach the seafloor until after September," says von Appen. "If you look at the period between early May and late November, the carbon export in the mixed-layer regime was only a third higher than in the meltwater regime." Rather, the pronounced stratification in 2017 promoted longer-term growth over several months, since carbon and nutrients were trapped in the upper layers. In contrast, the ice-free situation in 2018 produced a brief, intense bloom and rapid export, providing food and carbon for deep-sea ecosystems on the ocean floor. As such, the latter would seem to particularly benefit from the summertime conditions in the mixed-layer regime; in the meltwater regime, the intense stratification blocks nutrient input in the summer and deep water mixing in the winter.

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Big-headed ancient fish had land on its mind

Sophisticated CT scanning of the cranium of an Australian fish fossil has given new insights to explain how fish first left the water to invade land about 370 million years ago.

Supported by the Australian Research Council and international experts, the new research led by Flinders University palaeontologists studied Cladarosymblema narrienense, a 330 million-year-old fish from the Carboniferous Period found in Queensland, which is an ancestor of the first land animals or four-limbed vertebrate tetrapods.

Cladarosymblema is a type of 'megalichthyid' fish, a group which existed from the Devonian-to-Permian periods, typically living in freshwater environments, and they were large, predatory animals. Through scanning the fossil, they found evidence this fish had a brain similar to its eventual terrestrial descendants, compared to the brains of other fishes which remained living in water.

"This fish from Queensland is one of the best preserved of its kind in the entire world, in perfect 3D shape, which is why we chose to work on it," says Professor John Long, Strategic Professor in Palaeontology at Flinders University.

While this fish was first described in 1995, by Professor Long and others who had earlier explored and excavated the Queensland fossil site, parts of its anatomy have remained unknown -- although using Australia's largest cabinet CT scanner, located at Flinders University's Tonsley campus, as well as the Australian Synchrotron in Melbourne, has allowed researchers to unlock new data from this fossil.

New information obtained from often unseen internal bones has been revealed in these scans -- particularly in the gill arch skeleton, the shoulder girdle and the palate bones (the upper mouth roof area).

"This helps us to understand the functional morphology and relationships of Cladarosymblema," says Dr Alice Clement, lead author of the new paper and part of the Flinders Palaeontology Group.

Read more at Science Daily

When the brain switches from hearing to listening

What happens in the brain when simply hearing becomes listening? To answer this question, researchers at the University of Basel have traced the neuronal fingerprint of the two types of sound processing in the mouse brain.

It is intuitively clear to us that there is a difference between passive hearing and active listening. Attention and an animated state, but also movement, play a role in how sound processing in the brain adjusts accordingly. Neuroscientists Professor Tania Rinaldi Barkat and Dr. Gioia De Franceschi from the Department of Biomedicine at the University of Basel have provided an accurate account of what happens in this process in the journal Cell Reports.

For their study, the researchers examined the activity of neurons in four different areas in the brains of mice known to be involved in increasingly complex sound processing. During the experiment, the animals were either passively hearing the sounds played to them, or actively listening to them to receive a reward for detecting the sounds.

Activity pattern depends on various factors

It was shown that the majority of neurons changed their activity when switching between hearing and listening. "But this doesn't mean that all neurons behaved the same way," explains De Franceschi. "We actually found ten distinct and specific types of activity change."

While most of the neurons showed a change that was probably related to varying levels of attention, some of them also showed patterns of activity that were related to the arousal level of the mice, their movement, the availability of a reward, or a combination of these factors.

Impact on all processing levels

The auditory pathway in the brain consists of a number of different nuclei that relay acoustic information from the cochlea to the primary auditory cortex. Two of the four areas along the auditory pathway studied by the researchers are thought to be at a "higher level" in terms of processing complexity. "At the beginning of our study, we suspected that these were the areas particularly affected by attention to sounds," said Barkat. "Surprisingly, however, this wasn't the case." Attention also alters activity in brain areas previously thought to perform only basic forms of sound processing.

Read more at Science Daily

A spacecraft has 'touched' the sun for the first time

NASA's Parker Solar Probe reached the sun's extended solar atmosphere, known as the corona, and spent five hours there. The spacecraft is the first to enter the outer boundaries of our sun.

"This marks the achievement of the primary objective of the Parker mission and a new era for understanding the physics of the corona," said Justin C. Kasper, the first author, Deputy Chief Technology Officer at BWX Technologies, and a professor at the University of Michigan. The mission is led by the Johns Hopkins University Applied Physics Laboratory (JHU/APL).

The probe made the first direct observations of what lies within the sun's atmosphere, measuring phenomena previously only estimated.

The sun's outer edge begins at the Alfvén critical surface: the point below which the sun and its gravitational and magnetic forces directly control the solar wind. Many scientists think that sudden reverses in the sun's magnetic field, called switchbacks, emerge from this area.

"The concept of sending spacecraft into the magnetized atmosphere of the sun -- sufficiently close that the magnetic energy is greater than both ion and electron kinetic and thermal energy -- predated NASA itself," said Kasper.

In 2018, NASA launched Parker Solar Probe with the goal of finally reaching the sun's corona and making humanity's first visit to a star.

This past April, the probe spent five hours below the Alfvén critical surface in direct contact with the sun's plasma. Below that surface, the pressure and energy of the sun's magnetic field was stronger than the pressure and energy of the particles. The spacecraft passed above and below the surface three separate times during its encounter. This is the first time a spacecraft has entered the solar corona and touched the atmosphere of the sun.

Surprisingly, the researchers discovered that the Alfvén critical surface is wrinkled. The data suggest that the largest and most distant wrinkle of the surface was produced by a pseudostreamer -- a large magnetic structure more than 40 degrees across, found back on the innermost visible face of the sun. It is not currently known why a pseudostreamer would push the Alfvén critical surface away from the sun.

Researchers noticed far fewer switchbacks below the Alfvén critical surface than above it. The finding could mean that switchbacks do not form within the corona. Alternatively, low rates of magnetic reconnection on the sun's surface could have pumped less mass into the observed wind stream, resulting in fewer switchbacks.

The probe also recorded some evidence of a potential power boost just inside the corona, which may point to unknown physics affecting heating and dissipation.

"We have been observing the sun and its corona for decades, and we know there is interesting physics going on there to heat and accelerate the solar wind plasma. Still, we cannot tell precisely what that physics is," said Nour E. Raouafi, the Parker Solar Probe Project Scientist at JHU/APL. "With Parker Solar Probe now flying into the magnetically-dominated corona, we will get the long-awaited insights into the inner workings of this mysterious region."

The observations took place during Parker Solar Probe's eighth encounter with the sun. All data is publicly available in the NASA PSP archive. Several previous studies predicted the probe would first pass within the sun's boundaries in 2021.

The fastest known object built by humans, Parker Solar Probe has made many new discoveries since its launch, including on explosions that create space weather and the dangers of super-speedy dust.

The new findings suggest that direct observations by spacecraft have much to illuminate about the physics of coronal heating and solar wind formation. Having achieved its goal of touching the sun, Parker Solar Probe will now descend even deeper into the sun's atmosphere and linger for longer periods of time.

Read more at Science Daily

Tooth cavities provide unique ecological insight into living primates and fossil humans

Tooth decay is a common and unfortunate problem for many of us, but two University of Otago studies show it is also an issue for other primates, as well as our fossil relatives and ancestors.

Dr Ian Towle, the former Sir Thomas Sidey Postdoctoral Fellow in Otago's Faculty of Dentistry, says cavities are often considered to be a modern disease unique to humans, related to a diet rich in processed sugary foods. However, he says there is growing evidence tooth decay also occurs to a certain extent in other animal groups.

"Our new research shows caries also occurs in wild primates in low frequencies, although this is highly variable among groups and the teeth affected also vary," he says.

"This research helps us understand changes in diet and behaviour in human evolution; it also provides insight into particular behaviours in our living primate relatives."

For the research, published in the American Journal of Primatology and South African Journal of Science, Dr Towle and colleagues analysed more than 8000 extant primate and fossil human teeth and assessed variation in tooth decay patterns in relation to diet and behaviour.

They found 3.3 per cent of teeth in living primates had caries, which is similar to the incidence in fossil humans (ranging from 1 to 4 per cent of teeth in different species). However, all caries in the fossil humans samples studied were on back teeth, whereas the vast majority in living primates were on the front teeth.

"The fascinating feeding behaviours of animals such as chimpanzees, using their large front teeth to help suck sugary liquid out of figs, contributes to creating caries patterns rarely seen in humans.

"Indeed, in humans our back teeth are mostly affected by dental decay, whereas in other primates it's typically the front teeth," Dr Towle says.

Another interesting aspect of this research was that female chimpanzees had more caries than males (9.3 per cent compared to 1.8 per cent), with similar sex differences often evident in humans.

The work also revealed how similar decay patterns between captive primates and humans are, highlighting how primates often don't undertake specific natural behaviours in captivity.

"Caries occurred throughout human evolution and that doesn't seem to change much for millions of years, with less than 5 per cent of teeth affected. However, with the onset of agriculture, this increased rapidly to more than 20 per cent of teeth having cavities in some samples."

Read more at Science Daily

Visually stunning tree of all known life unveiled online

OneZoom is a one-stop site for exploring all life on Earth, its evolutionary history, and how much of it is threatened with extinction.

The OneZoom explorer -- available at onezoom.org -- maps the connections between 2.2 million living species, the closest thing yet to a single view of all species known to science. The interactive tree of life allows users to zoom in to any species and explore its relationships with others, in a seamless visualisation on a single web page. The explorer also includes images of over 85,000 species, plus, where known, their vulnerability to extinction.

OneZoom was developed by Imperial College London biodiversity researcher Dr James Rosindell and University of Oxford evolutionary biologist Dr Yan Wong. In a paper published today in Methods in Ecology and Evolution, Drs Wong and Rosindell present the result of over ten years of work, gradually creating what they regard as "the Google Earth of biology."

Dr Wong, from the Big Data Institute at the University of Oxford, said: "By developing new algorithms for visualisation and data processing, and combining them with 'big data' gathered from multiple sources, we've created something beautiful. It allows people to find their favourite living things, be they golden moles or giant sequoias, and see how evolutionary history connects them together to create a giant tree of all life on Earth."

Dr Rosindell, from the Department of Life Sciences at Imperial, said: "We have worked hard to make the tree easy to explore for everyone, and we also hope to send a powerful message: that much of our biodiversity is under threat."

The 'leaves' representing each species on the tree are colour coded depending on their risk of extinction: green for not threatened, red for threatened, and black for recently extinct. However, most of the leaves on the tree are grey, meaning they have not been evaluated, or scientists don't have enough data to know their extinction risk. Even among the species described by science, only a tiny fraction have been studied or have a known risk of extinction.

Dr Wong added: "It's extraordinary how much research there is still to be done. Building the OneZoom tree of life was only possible through sophisticated methods to gather and combine existing data -- it would have been impossible to curate all this by hand."

The OneZoom explorer is configured to work with touchscreens, and the developers have made the software free to download and use by educational organisations such as museums and zoos.

Dr Rosindell commented: "Two million species can feel like a number too big to visualise, and no museum or zoo can hold all of them! But our tool can help represent all Earth's species and allow visitors to connect with their plight. We hope that now this project is complete and available, many venues will be interested in using it to complement their existing displays."

Drs Rosindell and Wong have also set up a OneZoom charity with the aim of using their tree of life to "advance the education of the public in the subjects of evolution, biodiversity and conservation of the variety of life on Earth."

Uniquely, to support this charity, each leaf on the tree is available for sponsorship, allowing anyone to 'adopt' a species and enabling OneZoom to continue their mission. More than 800 leaves have currently been sponsored by individuals and selected organisations, many with personal messages of how they feel connected to the conservation of nature.

The team have also integrated the tree with data from the Wikipedia project to reveal the 'popularity' of every species, based on how often their Wikipedia page is viewed. Dr Wong said: "Perhaps unsurprisingly, humans come out on top, but it has swapped places a few times with the second most popular: the grey wolf -- the 'species' that includes all domestic dogs."

In the plant world, cannabis comes out on top, followed by cabbage, the potato, and the coconut. The most popular ray-finned fishes are sport fishing species, particularly salmon and trout.

Now the tree is complete, the team hope to create bespoke 'tours' and experiences of species connected in imaginative new ways -- such as tours of iridescent animals, medicinal plants, or even species named after celebrities. They have created a special screen capture tool for easy saving and sharing of user-generated tours.

Read more at Science Daily

Scientists develop an RNA-based breath test to detect COVID-19

In a new study in The Journal of Molecular Diagnostics, published by Elsevier, investigators report on the design and testing of a breathalyzer, known as the Bubbler, that relies on viral RNA detection to diagnose SARS-CoV-2. Its name is derived from the bubbling sound that occurs when the patient exhales into the device.

The Bubbler not only reverse transcribes RNA from airborne virus particles into DNA to be tested via PCR but can also barcode that DNA, allowing samples to be linked directly to the patient they have come from and be used for sequencing. It can be used for simultaneous batches of pooled samples and provides additional information such as viral load and strain identity and eliminates the need for stabilizing a sample, potentially allowing the assay to be performed at home.

"Involvement of the lower respiratory tract is often a precursor to severe COVID-19, so there is an argument for a more direct sampling focused on exhaled breath," explained lead investigator William G. Fairbrother, PhD, professor in the department of molecular biology, cell biology and biochemistry at Brown University in Providence, RI, USA.

Virus detection by the Bubbler is similar to a hospital-swab PCR test; however, it is a better measure of risk of contagion as it detects airborne viral particles. Swab tests can return a positive result for months after infection as they detect viral RNA fragments in cells that persist in previously infected cells. The Bubbler can also be adapted for environmental sampling in hospitals, transportation hubs, and closed environments like offices, ships, and planes, the investigators report.

Seventy patients treated in the Emergency Department of Rhode Island Hospital between May 2020 and January 2021 were screened. The study tested samples from three points in the respiratory tract. Tongue scrapes from the mouth (saliva/tongue scrapes) and from 15 seconds of exhaled breath collected in the Bubbler were compared to those from a conventional nasopharyngeal swab PCR test. The Bubbler is a glass tube with a glass pipette through which patients can exhale. The tube is filled with a reverse transcription reaction mixture and cold mineral oil.

The study determined that SARS-CoV-2 can be readily detected in the breath and is more predictive of lower respiratory tract involvement. Viral RNA is more enriched in the breath relative to oral samples, while oral samples include cells involved with SARS-CoV-2 replication that breath samples do not. This suggests the viral signal detected in the Bubbler comes from active viral particles.

"The Bubbler is more likely to be a better indicator of current infection than nasopharyngeal swabs," said Dr. Fairbrother. "Another advantage is the barcoding, which enables high-throughput RNA virus testing at a fraction of the cost of conventional testing. The barcode returns a viral sequence that also supports strain identification, which may prove useful as more information is learned about transmissibility and possible strain-specific treatment decisions."

The investigators also demonstrated how the Bubbler might be adapted to detect virus in airborne samples. To model the movement of droplets exhaled in human breath, three unique nucleic acid samples were added to three personal humidifiers at different locations at varied distances from the Bubbler in a room with high airflow and a room with low airflow. Although a detailed exploration of this application was beyond the scope of the study, the results demonstrate the potential to use aerosolized nucleic acids to quantitatively map airflow in indoor spaces, and to detect SARS-CoV-2 in the air.

"Such technology could be useful in restoring service to industries such as hotels, cruise ships, and casinos," Dr. Fairbrother observed. "There is also an epidemiological benefit to routine testing of air at early warning sites such as transportation hubs and hospital emergency departments."

Read more at Science Daily

Challenging Einstein’s greatest theory with extreme stars

Researchers at the University of East Anglia and the University of Manchester have helped conduct a 16-year long experiment to challenge Einstein's theory of general relativity.

The international team looked to the stars -- a pair of extreme stars called pulsars to be precise -- through seven radio telescopes across the globe.

And they used them to challenge Einstein's most famous theory with some of the most rigorous tests yet.

The study, published today in the journal Physical Review X, reveals new relativistic effects that, although expected, have now been observed for the first time.

Dr Robert Ferdman, from UEA's School of Physics, said: "As spectacularly successful as Einstein's theory of general relativity has proven to be, we know that is not the final word in gravitational theory.

"More than 100 years later, scientists around the world continue their efforts to find flaws in his theory.

"General relativity is not compatible with the other fundamental forces, described by quantum mechanics. It is therefore important to continue to place the most stringent tests upon general relativity as possible, to discover how and when the theory breaks down.

"Finding any deviation from general relativity would constitute a major discovery that would open a window on new physics beyond our current theoretical understanding of the Universe.

"And it may help us toward eventually discovering a unified theory of the fundamental forces of nature."

Led by Michael Kramer from the Max Planck Institute for Radio Astronomy in Bonn, Germany, the international team of researchers from ten countries, put Einstein's theory to the most rigorous tests yet.

Dr Ferdman said: "A pulsar is a highly magnetised rotating compact star that emits beams of electromagnetic radiation out of its magnetic poles.

"They weigh more than our sun but they are only about 15 miles across -- so they are incredibly dense objects that produce radio beams that sweep the sky like a lighthouse.

"We studied a double pulsar, which was discovered by members of the team in 2003 and presents the most precise laboratory we currently have to test Einstein's theory. Of course, his theory was conceived when neither these types of extreme stars, nor the techniques used to study them, could be imagined."

The double pulsar consists of two pulsars which orbit each other in just 147 minutes with velocities of about 1 million km/h. One pulsar is spinning very fast, about 44 times a second. The companion is young and has a rotation period of 2.8 seconds. It is their motion around each other which can be used as a near perfect gravity laboratory.

Seven sensitive radio telescopes were used to observe this double pulsar -- in Australia, the US, France, Germany, the Netherlands and in the UK (the Lovell Radio Telescope).

Prof Kramer said: "We studied a system of compact stars that is an unrivalled laboratory to test gravity theories in the presence of very strong gravitational fields.

"To our delight we were able to test a cornerstone of Einstein's theory, the energy carried by gravitational waves, with a precision that is 25 times better than with the Nobel-Prize winning Hulse-Taylor pulsar, and 1000 times better than currently possible with gravitational wave detectors."

He explained that the observations are not only in agreement with the theory, "but we were also able to see effects that could not be studied before''.

Prof Benjamin Stappers, from the University of Manchester, said: "The discovery of the double pulsar system was made as part of a survey co-led from the University of Manchester and presented us with the only known instance of two cosmic clocks which allow precise measurement of the structure and evolution of an intense gravitational field.

"The Lovell Telescope at the Jodrell Bank Observatory has been monitoring it every couple of weeks since then. This long baseline of high quality and frequent observations provided an excellent data set to be combined with those from observatories around the world."

Prof Ingrid Stairs from the University of British Columbia at Vancouver, said: "We follow the propagation of radio photons emitted from a cosmic lighthouse, a pulsar, and track their motion in the strong gravitational field of a companion pulsar.

"We see for the first time how the light is not only delayed due to a strong curvature of spacetime around the companion, but also that the light is deflected by a small angle of 0.04 degrees that we can detect. Never before has such an experiment been conducted at such a high spacetime curvature."

Prof Dick Manchester from Australia's national science agency, CSIRO, said: "Such fast orbital motion of compact objects like these -- they are about 30 per cent more massive than the Sun but only about 24 km across -- allows us to test many different predictions of general relativity -- seven in total!

"Apart from gravitational waves and light propagation, our precision allows us also to measure the effect of "time dilation" that makes clocks run slower in gravitational fields.

"We even need to take Einstein's famous equation E = mc2 into account when considering the effect of the electromagnetic radiation emitted by the fast-spinning pulsar on the orbital motion.

"This radiation corresponds to a mass loss of 8 million tonnes per second! While this seems a lot, it is only a tiny fraction -- 3 parts in a thousand billion billion(!) -- of the mass of the pulsar per second."

The researchers also measured -- with a precision of 1 part in a million(!) -- that the orbit changes its orientation, a relativistic effect also well known from the orbit of Mercury, but here 140,000 times stronger.

They realised that at this level of precision they also need to consider the impact of the pulsar's rotation on the surrounding spacetime, which is "dragged along" with the spinning pulsar.

Dr Norbert Wex from the MPIfR, another main author of the study, said: "Physicists call this the Lense-Thirring effect or frame-dragging. In our experiment it means that we need to consider the internal structure of a pulsar as a neutron star.

"Hence, our measurements allow us for the first time to use the precision tracking of the rotations of the neutron star, a technique that we call pulsar timing to provide constraints on the extension of a neutron star."

The technique of pulsar timing was combined with careful interferometric measurements of the system to determine its distance with high resolution imaging, resulting in a value of 2400 light years with only 8 per cent error margin.

Team member Prof Adam Deller, from Swinburne University in Australia and responsible for this part of the experiment, said: "It is the combination of different complementary observing techniques that adds to the extreme value of the experiment. In the past similar studies were often hampered by the limited knowledge of the distance of such systems."

This is not the case here, where in addition to pulsar timing and interferometry also the information gained from effects due to the interstellar medium were carefully taken into account.

Prof Bill Coles from the University of California San Diego agrees: "We gathered all possible information on the system and we derived a perfectly consistent picture, involving physics from many different areas, such as nuclear physics, gravity, interstellar medium, plasma physics and more. This is quite extraordinary."

Paulo Freire, also from MPIfR, said: "Our results are nicely complementary to other experimental studies which test gravity in other conditions or see different effects, like gravitational wave detectors or the Event Horizon Telescope.

"They also complement other pulsar experiments, like our timing experiment with the pulsar in a stellar triple system, which has provided an independent and superb test of the universality of free fall."

Read more at Science Daily

Experiment gives rise to social conventions between baboons

Kissing, shaking hands, or bowing are three possible ways of saying hello or goodbye. These gestures are social conventions: known to all individuals in a group, they allow one to address greetings quickly and appropriately. Conventions help solve coordination "problems" frequently encountered by the group, by providing efficient, stable and arbitrary solutions.

But conventions are not unique to the human species, as proven for the first time by the results of an experiment conducted at the CNRS primatology centre in Rousset-sur-Arc by researchers from the Cognitive Psychology Laboratory (CNRS/Aix-Marseille Université). Presented with a device requiring the coordination of two individuals, Guinea baboons established common rules for the whole group in about three days.

The baboons were presented with the following task: two different images were randomly selected from a set and presented on screens to two monkeys. If they wanted a reward, the baboons had to choose the same picture, meaning there was not one possible answer to the experiment, but several. Individuals had to decide together on a solution to the problem and agree on the choices to be made.

The primates quickly developed a hierarchy between images: for example, they agreed on the choice of the pink square when it was presented with a light blue square, and chose the yellow square next to a pink or light blue square. When the two baboons could no longer see each other, the overall performance of the group was hardly affected. This suggests that the baboons were not simply using imitation as a strategy to solve this problem, but had instead coordinated on these choices.

These conventions between baboons are stable over time, efficient, and arbitrary since the choice of images was not dictated. They therefore present the three characteristics of human social conventions. The scientists propose that groups of non-human primates in the wild be observed in new ways to detect such conventions.

From Science Daily

Farmed seafood supply at risk if we don’t act on climate change

The supply of farmed seafood such as salmon and mussels are projected to drop 16 per cent globally by 2090 if no action is taken to mitigate climate change, according to a new UBC study.

Ocean-farmed seafood or mariculture is often seen as a panacea to the problems of depleted stocks of wild fish and growing human demand, and is expected to grow substantially in the coming years, says lead author Dr. Muhammed Oyinlola (he/him), a postdoctoral research fellow at the Institute for the Oceans and Fisheries (IOF). But the new modelling study highlights the industry is as vulnerable to the effects of climate change as any other. "If we continue to burn fossil fuels at our current rate, the amount of seafood such as fish or mussels able to be farmed sustainably will increase by only eight per cent by 2050, and decline by 16 per cent by 2090."

By comparison, in a low emissions scenario where the action is taken to mitigate climate change, mariculture is projected to grow by about 17 per cent by the mid-21st century and by about 33 per cent by the end of the century, relative to the 2000s.

The model takes into account many factors, including changing ocean temperatures, suitable mariculture areas in the future, and the supply of fishmeal and fish oil. It examined approximately 70 per cent of the world's mariculture production as of 2015, focusing on Exclusive Economic Zones, where most of the world's seafood farming occurs.

Climate change will affect mariculture production differently depending on where farms are in the world, and what they produce, says Dr. Oyinlola. The hardest-hit regions in the high-emissions scenario -- Norway, Myanmar, Bangladesh, the Netherlands, and China -- could see their mariculture production decline by as much as 40 to 90 per cent.

Climate effects on mariculture include changes in the area of viable ocean in which to farm fish as well as the stock of food used to feed them. Fish farms tend to use fishmeal and fish oil, which are largely composed of smaller fish such as herring and anchovy -- stocks which are also threatened by climate change.

"Some regions produce more bivalves, such as mussels, oysters and clams, and in these regions, the impact is smaller," Dr. Oyinlola said. "In regions that produce more finfish, such as salmon, the impact will be high due to reduction in the supply of fishmeal and fish oil."

Under current carbon emission rates, finfish farming, such as salmon, is projected to decrease globally by three per cent by 2050, and 14 per cent by 2090. Bivalve farming is projected to increase by 2050 and decrease by 2090 under both climate scenarios.

Countries where mariculture is prominent especially for finfish production, such as Norway, Iceland, Finland, Chile, and Bangladesh, will be hit hardest, according to Dr. Oyinlola, whereas regions that produce more bivalves will be more stable or in Canada's case, will grow.

Vegetarian fish: feeding fish soybeans

The study also found that substituting fishmeal and fish oil for plant-based foods such as soybeans could help alleviate the effects of climate change for fish farms.

When a quarter of the fish food was substituted with alternatives, under a low emissions scenario, mariculture production was projected to increase by 25 per cent by 2050 and 31 per cent by 2090.

With no change to current emissions, when a quarter of the fish food was substituted with alternatives, mariculture production was projected to increase by 15 per cent by 2050 and four per cent by 2090. When half the food was substituted in both climate scenarios, these percentages increased.

"This study highlights the need to diversify mariculture development from the current focus on fish," said senior author Dr. William Cheung (he/him), IOF professor and director. Climate-adapted mariculture would include species that are not dependent on fishmeal and fish oil, such as shellfish or algae, or those that can utilize non-fish-based feed. "Farming these species generally helps to reduce exposure of seafood farming to climate hazards."

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Life arose on hydrogen energy, researchers suggest

How did the first chemical reactions get started at the origin of life and what was their source of energy? Researchers at the Heinrich Heine University Düsseldorf (HHU) have reconstructed the metabolism of the last universal common ancestor, LUCA. They found that almost all chemical steps used by primordial life to piece together the molecular building blocks of cells are energy releasing reactions. This identified the long-sought source of energy needed to drive these reactions forward, which has been hiding in plain sight. The energy required to synthesize the building blocks of life comes from within metabolism itself, as long as one essential starting compound is included. The secret ingredient that releases the energy from within at life's origin is the cleanest, greenest, newest and oldest of all energy carriers: Hydrogen gas, H2.

The team of Prof. Dr. William Martin in the Institute for Molecular Evolution at the HHU investigates how and where life arose on the early Earth. Their approach is experimental and computational. In the laboratory, they run chemical experiments to investigate reactions between hydrogen and carbon dioxide, CO2, using catalysts and conditions found in submarine hydrothermal vents. At the computer, they have developed a form of molecular archaeology that allows them to uncover the many different traces of primordial life that are preserved in the proteins, DNA and chemical reactions of modern cells.

In their latest work, they investigated the question of what kind of chemical environment fostered the chemical reactions that gave rise to metabolism, and later to LUCA itself, and where the energy came from that was needed to drive those reactions forward. To do that, they looked not at genes, but at the information contained within the chemical reactions of life themselves. They identified 402 metabolic reactions that have gone virtually unchanged since the origin of life roughly 4 billion years ago. Because these reactions are common to all cells, they were also present in LUCA. They shed light on how primordial life dealt with energy in metabolism and where it obtained the energy needed to make life's chemical reactions go forward.

Jessica Wimmer, a PhD student in the institute and lead author on the new paper, was particularly interested in the energy balance of LUCA's metabolic reactions, because all life requires energy. For that she made a catalogue of the 402 reactions that the simple and ancient among modern cells -- bacteria and archaea -- use to construct the building blocks of life: the 20 amino acids, the bases of DNA and RNA, and the 18 vitamins (cofactors) that are essential for metabolism. In the most primitive of modern cells, and in Wimmer's computer analyses, these compounds are synthesized from simple molecules that are present in the modern environment and that were also present in hydrothermal vents on the early Earth: hydrogen (H2), carbon dioxide (CO2) and ammonia (NH3). The result was the metabolic network of LUCA.

When asked about the motivation behind the central question of the new study, Jessica Wimmer says: "We wanted to know where the energy came from that drove primordial metabolism forward. At the very onset of metabolic reactions some 4 billion years ago, there were no proteins or enzymes to catalyze reactions because they had not yet evolved. Metabolism had to arise from reactions that could take place in the environment, perhaps with help from inorganic catalysts. But catalysts or not, in order to go forward, the reactions have to release energy. Where did that energy come from? There have been lots of suggestions for possible sources of metabolic energy in the literature. But nobody ever looked into the reactions of metabolism itself." To find sources of energy in metabolic reactions, the team calculated the amount of free energy, also called Gibbs energy, that is released or consumed in each reaction.

The result: LUCA's metabolism required no external source of energy such as UV light, meteorite impacts, volcanic eruptions, or radioactivity. On the contrary, in an environment typical of many modern submarine hydrothermal vents, the energy needed for the reactions of metabolism to go forward stems from within metabolism itself. Stated another way, almost all of LUCA's metabolic reactions liberate energy all by themselves: the energy for life stems from life itself. Martin, senior author of the study, says: "That is exciting, because the 400 interconnected reactions of central metabolism, which seem so hopelessly complex upon first encounter, suddenly reveal a natural tendency to unfold all by themselves under the right conditions."

To arrive at that conclusion, the team had to first investigate the energetics of the 402 reactions using computer programs that simulate different environmental conditions, so as to distinguish energetically favorable from unfavorable combinations. This is important because whether or not a reaction releases energy often depends upon environmental conditions. They surveyed conditions ranging from pH 1 (acidic) to pH 14 (alkaline), temperatures from 25 to 100 °C, and different relative amounts of reactants to products. They looked with particular care at the energetic role of hydrogen. Wimmer: "Without hydrogen, nothing happens at all, because hydrogen is required to get carbon from CO2 incorporated into metabolism in the first place."

The energetically optimal conditions fall within an alkaline pH range around pH 9 and a temperature around 80 °C, with hydrogen required for CO2 fixation. Putting this result in context, Martin explains: "This is almost exactly what we see at Lost City, a H2-producing hydrothermal field in the Mid-Atlantic. In an environment like that, about 95-97 % of LUCA's metabolic reactions could go forward spontaneously, that is, without the need for any other source of energy. In the abyssal darkness of hydrothermal systems, H2 is chemical sunlight. Modern energy research exploits exactly the same properties of hydrogen as life does. It is just that life has four billion years of experience with hydrogen technology, while we are just getting started."

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'Supermeres' may carry clues to cancer, Alzheimer's disease and COVID-19

Researchers at Vanderbilt University Medical Center have discovered a nanoparticle released from cells, called a "supermere," which contains enzymes, proteins and RNA associated with multiple cancers, cardiovascular disease, Alzheimer's disease and even COVID-19.

The discovery, reported in Nature Cell Biology, is a significant advance in understanding the role extracellular vesicles and nanoparticles play in shuttling important chemical "messages" between cells, both in health and disease.

"We've identified a number of biomarkers and therapeutic targets in cancer and potentially in a number of other disease states that are cargo in these supermeres," said the paper's senior author, Robert Coffey, MD. "What is left to do now is to figure out how these things get released."

Coffey, the Ingram Professor of Cancer Research and professor of Medicine and Cell & Developmental Biology, is internationally known for his studies of colorectal cancer. His team is currently exploring whether the detection and targeting of cancer-specific nanoparticles in the bloodstream could lead to earlier diagnoses and more effective treatment.

In 2019 Dennis Jeppesen, PhD, a former research fellow in Coffey's lab who is now a research instructor in Medicine, used advanced techniques to isolate and analyze small membrane-enclosed extracellular vesicles called "exosomes."

That year, using high-speed ultracentrifugation, another of Coffey's colleagues, Qin Zhang, PhD, research assistant professor of Medicine, devised a simple method to isolate a nanoparticle called an "exomere" that lacks a surface coat.

In the current study, Zhang took the "supernatant," or fluid that remains after the exomeres have been spun into a "pellet," and spun the fluid faster and longer.

The result was a pellet of nanoparticles isolated from the supernatant of the exomere spin -- which the researchers named supermeres. "They're also super-interesting," Coffey quipped, "because they contain many cargo previously thought to be in exosomes."

For one thing, supermeres carry most of the extracellular RNA released by cells and which is found in the bloodstream. Among other functional properties, cancer-derived supermeres can "transfer" drug resistance to tumor cells, perhaps via the RNA cargo they deliver, the researchers reported.

Supermeres are important carriers of TGFBI, a protein that in established tumors promotes tumor progression. TGFBI thus may be a useful marker in liquid biopsies for patients with colorectal cancer, the researchers noted.

They also carry ACE2, a cell-surface receptor that plays a role in cardiovascular disease and is the target of the COVID-19 virus. This raises the possibility that ACE2 carried by supermeres could serve as a "decoy" to bind the virus and prevent infection.

Another potentially important cargo is APP, the amyloid-beta precursor protein implicated in the development of Alzheimer's disease. Supermeres can cross the blood-brain barrier, suggesting that their analysis could improve early diagnosis or possibly even targeted treatment of the disease.

"The identification of this rich plethora of bioactive molecules … raises interesting questions about the function of supermeres, and heightens interest in the potential of these particles as biomarkers for diseases," researchers at the University of Notre Dame noted in a review published with the paper.

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Citizen scientists find young-Jupiter-like object missed by previous exoplanet searches

Citizen scientists have discovered a new object orbiting a Sun-like star that had been missed by previous searches. The object is very distant from its host star -- more than 1,600 times farther than the Earth is from the Sun -- and is thought to be a large planet or a small brown dwarf, a type of object that is not massive enough to burn hydrogen like true stars. Details about the new world are published today in The Astrophysical Journal.

"This star had been looked at by more than one campaign searching for exoplanet companions. But previous teams looked really tight, really close to the star," said lead author Jackie Faherty, senior scientist in the American Museum of Natural History's Department of Astrophysics and co-founder of the citizen science project Backyard Worlds: Planet 9, which led to the object's discovery. "Because citizen scientists really liked the project, they found an object that many of these direct imaging surveys would have loved to have found, but they didn't look far enough away from its host."

The Backyard Worlds project lets volunteers search through nearly five years of digital images taken from NASA's Wide-field Infrared Survey Explorer (WISE) mission to try to identify new worlds inside and outside of our solar system. If an object close to Earth is moving, it will appear to "jump" in the same part of the sky over the years, similar to an object "moving" in a flipbook. Users can then flag these objects for further study by scientists.

In 2018, Backyard Worlds participant Jörg Schümann, who lives in Germany, alerted scientists to a new co-moving system: an object that appeared to be moving with a star. After confirming the system's motion, scientists used telescopes in California and Hawai'i to observe the star and object separately and were immediately excited by what they saw.

The new object is young and has a low mass, between 10 and 20 times the mass of Jupiter. This range overlaps with an important cutoff point -- 13 times the mass of Jupiter -- which is sometimes used to distinguish planets from brown dwarfs. But scientists still aren't sure how heavy planets can be, which can make relying on this cutoff challenging. "We don't have a very good definition of the word 'planet,'" said Faherty.

Another defining feature is how they form: planets form from material gathering in disks around stars, while brown dwarfs are born from the collapse of giant clouds of gas, similar to how stars form. But the physical properties of this new object do not provide any clues to its formation. "There are hints that maybe it's more like an exoplanet, but there's nothing conclusive yet. However, it is an outlier," said Faherty.

What surprised the team the most is the new object's relationship to its host star. The object is farther away from the star than expected based on its comparatively low mass -- over 1,600 times farther than the Earth is from the Sun. Few objects with such different masses from their host star have been found this far apart.

Ultimately, this discovery may help scientists get a better sense of how solar systems form, which is crucial to understanding the origins of life in the universe. "You had an exoplanet community just staring so close to it," said Faherty. "And we just pulled out a little, and we found an object. That makes me excited about what we might be missing in giant planets that might exist around these stars," said Faherty. "Sometimes, you need to broaden your scope."

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Mini-jet found near Milky Way's supermassive black hole

Our Milky Way's central black hole has a leak. This supermassive black hole looks like it still has the vestiges of a blowtorch-like jet dating back several thousand years. NASA's Hubble Space Telescope hasn't photographed the phantom jet but has helped find circumstantial evidence that it is still pushing feebly into a huge hydrogen cloud and then splattering, like the narrow stream from a hose aimed into a pile of sand.

This is further evidence that the black hole, with a mass of 4.1 million Suns, is not a sleeping monster but periodically hiccups as stars and gas clouds fall into it. Black holes draw some material into a swirling, orbiting accretion disk where some of the infalling material is swept up into outflowing jets that are collimated by the black hole's powerful magnetic fields. The narrow "searchlight beams" are accompanied by a flood of deadly ionizing radiation.

"The central black hole is dynamically variable and is currently powered down," said Gerald Cecil of the University of North Carolina in Chapel Hill. Cecil pieced together, like a jigsaw puzzle, multiwavelength observations from a variety of telescopes that suggest the black hole burps out mini-jets every time it swallows something hefty, like a gas cloud. His multinational team's research has just been published in the Astrophysical Journal.

In 2013 evidence for a stubby southern jet near the black hole came from X-rays detected by NASA's Chandra X-ray Observatory and radio waves detected by the Jansky Very Large Array telescope in Socorro, New Mexico. This jet too appears to be plowing into gas near the black hole.

Cecil was curious if there was a northern counter-jet as well. He first looked at archival spectra of such molecules as methyl alcohol and carbon monosulfide from the ALMA Observatory in Chile (Atacama Large Millimeter/Submillimeter Array), which uses millimeter wavelengths to peer through the veils of dust between us and the galactic core. ALMA reveals an expanding, narrow linear feature in molecular gas that can be traced back at least 15 light-years to the black hole.

By connecting the dots, Cecil next found in Hubble infrared-wavelength images a glowing, inflating bubble of hot gas that aligns to the jet at a distance of at least 35 light-years from the black hole. His team suggests that the black hole jet has plowed into it, inflating the bubble. These two residual effects of the fading jet are the only visual evidence of it impacting molecular gas.

As it blows through the gas the jet hits material and bends along multiple streams. "The streams percolate out of the Milky Way's dense gas disk," said co-author Alex Wagner of Tsukuba University in Japan. "The jet diverges from a pencil beam into tendrils, like that of an octopus." This outflow creates a series of expanding bubbles that extend out to at least 500 light-years. This larger "soap bubble" structure has been mapped at various wavelengths by other telescopes.

Wagner and Cecil next ran supercomputer models of jet outflows in a simulated Milky Way disk, which reproduced the observations. "Like in archeology, you dig and dig to find older and older artifacts until you come upon remnants of a grand civilization," said Cecil. Wagner's conclusion: "Our central black hole clearly surged in luminosity at least 1 millionfold in the last million years. That sufficed for a jet to punch into the Galactic halo."

Previous observations by Hubble and other telescopes found evidence that the Milky Way's black hole had an outburst about 2-4 million years ago. That was energetic enough to create an immense pair of bubbles towering above our galaxy that glow in gamma-rays. They were first discovered by NASA's Fermi Gamma-ray Space Telescope in 2010 and are surrounded by X-ray bubbles that were discovered in 2003 by the ROSAT satellite and mapped fully in 2020 by the eROSITA satellite.

Hubble ultraviolet-light spectra have been used to measure the expansion velocity and composition of the ballooning lobes. Hubble spectra later found that the burst was so powerful that it lit up a gaseous structure, called the Magellanic stream, at about 200,000 light-years from the galactic center. Gas is glowing from that event even today.

To get a better idea of what's going on, Cecil looked at Hubble and radio images of another galaxy with a black hole outflow. Located 47 million light-years away, the active spiral galaxy NGC 1068 has a string of bubble features aligned along an outflow from the very active black hole at its center. Cecil found that the scales of the radio and X-ray structures emerging from both NGC 1068 and our Milky Way are very similar. "A bow shock bubble at the top of the NGC 1068 outflow coincides with the scale of the Fermi bubble start in the Milky Way. NGC 1068 may be showing us what the Milky Way was doing during its major power surge several million years ago."

The residual jet feature is close enough to the Milky Way's black hole that it would become much more prominent only a few decades after the black hole powers up again. Cecil notes that "the black hole need only increase its luminosity by a hundredfold over that time to refill the jet channel with emitting particles. It would be cool to see how far the jet gets in that outburst. To reach into the Fermi gamma-ray bubbles would require that the jet sustain for hundreds of thousands of years because those bubbles are each 50,000 light years across!"

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