Marsquake!

Seismic waves from the largest marsquake ever detected revealed possible past meteoroid impact

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - LOS ANGELES

The largest earthquake ever detected on Mars has revealed layers in its crust that could indicate past collision with a massive object, such as a meteoroid. Previous data has suggested the past occurrence of a large impact, and the findings offer evidence that might support this hypothesis.

The research, led by UCLA planetary scientists and published in two papers in Geophysical Research Letters, could also indicate that alternating layers of volcanic and sedimentary rocks lie beneath the surface.

The 4.7 magnitude earthquake, or marsquake, happened in May 2022 and lasted more than four hours, releasing five times more energy than any previously recorded quake. Though moderate by Earth standards, the temblor was nonetheless powerful enough to send seismic surface waves completely around the planet’s circumference, the first time this phenomenon has been observed on Mars.

The readings were taken from InSight, which landed on Mars in 2018. InSight is the first outer space seismometer to study in-depth the “inner space” of Mars: its crust, mantle and core.

“The seismometer aboard the InSight lander has recorded thousands of marsquakes but never one this large, and it took over three years after landing to record it,” said corresponding author Caroline Beghein, a professor of Earth, planetary and space sciences. “This quake generated different kinds of waves, including two types of waves trapped near the surface. Only one of those two has been observed on Mars before, after two impact events, never during a marsquake.”

Mapping the seismic activity, the location and frequency of impacts on Mars and the interior structure is important for future missions to the red planet as it will inform scientists and engineers where and how to build structures to ensure the safety of future human explorers.

As on Earth, studying how seismic waves travel through rocks can give scientists clues about the temperature and composition of the planet below the surface that help inform the search for underground water or magma. It also helps scientists understand the past forces that shaped the planet.

Beghein’s group combined measurements from two types of surface waves, called Love and Rayleigh waves, to infer the speed of underground shear-waves, which travel horizontally and move rocks perpendicular to the direction of wave propagation. This is the first time Love waves have been observed in conjunction with Rayleigh waves on Mars.

The measurements showed that the shear-waves move faster in the crust when rocks between 10 and 25 kilometers underground oscillate in a direction almost parallel to the planet surface than if the rocks vibrate in the vertical direction.

“This wave speed information is related to deformations inside the crust,” Beghein said. “Alternating volcanic rocks and sedimentary layers, which were deposited long ago, or a very large impact, such as a meteoroid, most likely account for the seismic wave measurements we observed.”

These data also enabled Jiaqi Li, a UCLA postdoctoral researcher in Beghein’s group, to learn that shear-waves move faster in the Martian southern highland areas than in the northern lowlands. The northern hemisphere of Mars has a lower elevation and is covered with more craters than the southern hemisphere. A large impact in the lowlands has been the prevalent theory to explain the origin of this difference.

The new data point toward the presence of thick accumulations of sedimentary rocks and relatively higher porosity in the lowlands.  Larger amounts of gas, such as trapped air in these sedimentary rocks, slow the waves down.  

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JOURNAL

Geophysical Research Letters

DOI

10.1029/2022GL101508 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Crustal Anisotropy in the Martian Lowlands From Surface Waves

ARTICLE PUBLICATION DATE

14-Dec-2022

Some claim culture affects our basic visual perception. A UCLA study takes a fresh look

Researchers found little difference in how people of East Asian and European descent performed on a famous test

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - LOS ANGELES

Research claims made over recent years that people of East Asian and European descent perform differently on a well-known visual perception test as a result of fundamental cultural differences may be overstated, according to UCLA psychologists.

In new experiments conducted by the UCLA researchers, white, Asian American and recent Asian immigrant college students in the U.S. performed similarly on the test, known as the rod-and-frame task, which measures the influence of surrounding contextual visual information on perception.  

The findings, published in PLOS One suggest that the basics of visual perception, such as object orientation, are largely independent of cultural variation and apply broadly across human populations.

What is the rod-and-frame task and what is the debate?

The rod-and-frame task asks participants to view a single line within a square frame and to orient that line straight up and down vertically. The difficulty comes when the surrounding frame is tilted in various ways, which can influence viewers’ perception of the vertical orientation of the line.

Historically, much of this type of research had been conducted in Western countries with college students as participants, raising questions about how accurate the data is for people in other cultures and parts of the world.

In some previous, highly publicized work produced since 2000, researchers exploring that question found that East Asians and Europeans performed differently on the rod-and-frame task; East Asians, the researchers said, tended to focus on the square frame first or give equal attention to the frame and the line, while Europeans placed more emphasis on the line.

These researchers hypothesized that cultural influences could be at the root of the differences, with participants from East Asian cultures, which social scientists say emphasize the embeddedness of individuals within collective groups, perceiving more holistically and taking context into consideration. Similarly, participants from Western cultures, which social scientists say tend to elevate individuals over groups, may perceive more analytically and independently of context. The claims bucked against a fundamental assumption in visual neuroscience research that basic visual functions are the same for humans everywhere, as well as for non-human primates.

“If culture influences even the most basic visual functions, then all studies must take into consideration the cultures of the participants and the fact that findings might not apply to other cultures,” said Zili Liu, a UCLA psychology professor and the current study’s corresponding author. “Perhaps more importantly, vision research with animals will have limited utility.”

If these previous findings were true, Liu noted, it would stand to reason that people who have been immersed in another’s culture for enough time will start to perform similarly to people raised in that culture on the rod-and-frame task.

“I thought UCLA was a good place to test this because we have many Asian American students, as well as more recent Asian immigrants to the U.S., and they should serve as supportive evidence that the longer people have lived here, the less the data would look like Asian nations,” Liu said.

Reassessing the influence of culture on the rod-and-frame task

Chéla R Willey, a UCLA doctoral student at the time of the study who is now an assistant professor at Loyola Marymount University, recruited a diverse group of 342 UCLA students to perform the rod-and-frame task using virtual reality goggles. All participating students answered a questionnaire about their ethnicity and country of citizenship. In this first experiment, participants used a computer mouse to rotate the center line to make it vertical.

In a second experiment, 216 of the 342 students judged whether the line was clockwise or counter-clockwise with respect to the vertical.

Among the 84 East Asian participants who completed both experiments, 40 were second-generation Americans (born in the U.S. with at least one immigrant parent) or beyond and 44 were first generation or non-citizens. Among the white dual-experiment participants, nearly all — 51 out of 57 — were second-generation Americans or beyond, while six were first generation or non-citizens.

The results of the first experiment revealed that a participant’s cultural background had little, if anything, to do with how they judged the line’s vertical orientation inside both tilted and non-tilted frames. In the second experiment, the researchers once again found no significant difference between ethnicity or generation. They did, however, observe a well-known gender difference in which frame tilt affects the perception of women more than men.

“The gender finding replicates what has been found in many other studies, indicating that our data are of reasonable quality,” Liu said. “Our failure to replicate the cultural effect therefore suggests that culture might not influence orientation perception that much.”

The work lends support to research showing that some basic mechanisms of visual perception are universal and that for these kinds of studies, it might not matter much which population the researchers use.

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JOURNAL

PLoS ONE

DOI

10.1371/journal.pone.0276393 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Re-assessing the role of culture on the visual orientation perception of the rod and frame test

When using virtual reality as a teaching tool, context and ‘feeling real’ matter

People remember foreign vocabulary better when lessons are associated with distinct environments, UCLA study finds

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - LOS ANGELES

A new study by UCLA psychologists reveals that when VR is used to teach language, context and realism matter.

The research is published in the journal npj Science of Learning.

“The context in which we learn things can help us remember them better,” said Jesse Rissman, the paper’s corresponding author and a UCLA associate professor of psychology. “We wanted to know if learning foreign languages in virtual reality environments could improve recall, especially when there was the potential for two sets of words to interfere with each other.”

Researchers asked 48 English-speaking participants to try to learn 80 words in two phonetically similar African languages, Swahili and Chinyanja, as they navigated virtual reality settings.

Wearing VR headsets, participants explored one of two environments — a fantasy fairyland or a science fiction landscape — where they could click to learn the Swahili or Chinyanja names for the objects they encountered. Some participants learned both languages in the same VR environment; others learned one language in each environment.

Participants navigated through the virtual worlds four times over the course of two days, saying the translations aloud each time. One week later, the researchers followed up with a pop quiz to see how well the participants remembered what they had learned.

The results were striking: Subjects who had learned each language in its own unique context mixed up fewer words and were able to recall 92% of the words they had learned. In contrast, participants who had learned both sets of words in the same VR context were more likely to confuse terms between the two languages and retained only 76% of the words.

The study is particularly timely because so many K-12 schools, colleges and universities moved to develop online learning platforms during the COVID-19 pandemic.

“Apps like Zoom provide a rather bland context for learning,” Rissman said. “As VR technology becomes more ubiquitous and affordable, remote learners could be instantly teleported into unique and richly featured contexts for each class.”

The experiment was designed by Rissman and Joey Ka-Yee Essoe, the study’s first author who was a UCLA doctoral student at the time.

Rissman said a key predictor of the subjects’ ability to retain what they had learned was how immersed in the VR world they felt. The less a participant felt like a subject in a psychology experiment — and the more “at one” they felt with their avatar — the more the virtual contexts were able to positively affect their learning.

“The more a person’s brain was able to reconstruct the unique activity pattern associated with the learning context, the better able they were to recall the foreign words they had learned there,” Rissman said.

Psychologists have long understood that people tend to recall things more readily if they can remember something about the surrounding context in which they learned it — the so-called “context crutch” phenomenon. But when information is tied to contextual cues, people can have trouble recalling it later in the absence of those cues.

For example, students might learn Spanish in the same kind of classroom where they learn other subjects. When that happens, their Spanish vocabulary can be tied to the same contextual cues that are tied to other material they’ve been taught, like the Pythagorean theorem or a Shakespeare play. Not only does that similar context make it easier to mix up or forget what they have learned, but it also can make it harder to remember any of the information outside of a classroom setting.

“A key takeaway is that if you learn the same thing in same environment, you’ll learn it really fast,” said Essoe, who is now a postdoctoral scholar at Johns Hopkins University. “But even though you learn fast, you might have trouble with recall. What we were able to harness in this research takes advantage of both learning fast and improving recall in new environment.”

To understand the brain mechanisms that support context-dependent learning, the researchers recruited a separate group of participants and scanned their brains with functional magnetic resonance imaging, or fMRI. As the subjects attempted to recall foreign words while in the scanner, their brain activity indicated that they were thinking about the context in which they had learned each word.

That finding suggests that virtual reality can enhance learning if it is convincingly produced and if different languages or scholastic subjects are taught in highly distinctive environments.

Rissman said although the study only assessed how people learned a foreign language, the results indicate that VR could be useful for teaching other subjects as well. Similar approaches could also be used for mental and behavioral health therapies and to help patients adhere to doctors’ instructions after medical visits: Patients might be able to remember such guidance better if they’re in their own homes while chatting online with their doctors, for example.

Said Essoe: “Variable contexts can ground information in more environmental cues.”

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JOURNAL

npj Science of Learning

DOI

10.1038/s41539-022-00147-6 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Enhancing learning and retention with distinctive virtual reality environments and mental context reinstatement

Rosenstiel marine researcher identifies new bottlenose dolphin subspecies

Peer-Reviewed Publication

UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF MARINE, ATMOSPHERIC, AND EARTH SCIENCE

 

IMAGE: NEW SUBSPECIES, CALLED THE EASTERN TROPICAL PACIFIC BOTTLENOSE DOLPHIN (TURSIOPS TRUNCATUS NUUANU), IS SMALLER THAN OTHER COMMON BOTTLENOSE DOLPHINS. view more 

CREDIT: NOAA

A marine researcher at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science has identified a new bottlenose dolphin subspecies found only in the eastern tropical Pacific Ocean.  “While there is a common belief that all dolphin species are already known, improvements in technologies and methodologies are helping to reveal a greater biodiversity in more recent years,” said Ana Costa, Ph.D., a Rosenstiel lecturer specializing in marine mammalogy.

After examining and analyzing a series of specimens, Costa and collaborators of the National Oceanic and Atmospheric Administration, found that the new subspecies, called the Eastern Tropical Pacific bottlenose dolphin (Tursiops truncatus nuuanu), is smaller than other common bottlenose dolphins. These dolphins likely prefer deep offshore waters between southern Baja California and the Galapagos Islands, she added.

In this study, which began in 2016, Costa and her colleagues examined total body length and skull morphology of common bottlenose dolphin specimens that were collected in the Pacific Ocean and are archived in several museum collections in the United States. They used multivariate and clustering analyses to examine the level of differentiation among the bottlenose dolphin populations.

“We found two distinct morphological clusters: the new subspecies found in the eastern tropical Pacific (ETP) and the common bottlenose dolphins found primarily in the eastern and western North Pacific waters,” Costa said. “The ETP bottlenose dolphins might be differentiating due to the distinct environmental conditions in these waters, such as oxygen and salinity levels and temperature conditions.”

Reflecting on the study, Costa said that a greater understanding of marine mammal populations is vital for preserving and protecting different species and subspecies at a time of global warming. “The conservation and management of marine life should be an international priority,” she added.

The  study, “Tursiops truncatus nuuanu, a new subspecies of the common bottlenose dolphin from the eastern tropical Pacific,” was published December 10, 2022 in the Journal of Mammalian Evolution. Additional authors were Eric Archer, Ph.D., and the late William Perrin, Ph.D., of the Southwest Fisheries Science Center, and Patricia Rosel, Ph.D., of the Southeast Fisheries Science Center, all of the National Oceanic and Atmospheric Administration (NOAA).

 

About the University of Miami

The University of Miami is a private research university and academic health system with a distinct geographic capacity to connect institutions, individuals, and ideas across the hemisphere and around the world. The University’s vibrant and diverse academic community comprises 12 schools and colleges serving more than 17,000 undergraduate and graduate students in more than 180 majors and programs. Located within one of the most dynamic and multicultural cities in the world, the University is building new bridges across geographic, cultural, and intellectual borders, bringing a passion for scholarly excellence, a spirit of innovation, a respect for including and elevating diverse voices, and a commitment to tackling the challenges facing our world. Founded in the 1940’s, the Rosenstiel School of Marine, Atmospheric, and Earth Science is one of the world’s premier marine and atmospheric research institutions. Offering dynamic interdisciplinary academics, the Rosenstiel School is dedicated to helping communities to better understand the planet, participating in the establishment of environmental policies, and aiding in the improvement of society and quality of life. www.earth.miami.edu.

 

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JOURNAL

Journal of Mammalian Evolution

DOI

10.1007/s10914-022-09641-5 

METHOD OF RESEARCH

Data/statistical analysis

ARTICLE TITLE

Tursiops truncatus nuuanu, a new subspecies of the common bottlenose dolphin from the eastern tropical Pacific

Children and young people need lessons in building strong relationships to counteract negative role models and “Disneyfied” portrayals of love, experts say

Peer-Reviewed Publication

UNIVERSITY OF EXETER

Children should get lessons in school on how to build strong relationships to counteract negative role models and any “Disneyfied” portrayals of love they are exposed to, experts have said.

Learning how to build and sustain a strong partnership should be an integral part of work in schools to promote good health and wellbeing, according to a new study.

Relationship distress is associated with public health problems such as alcohol misuse, obesity, poor mental health, and child poverty.

Children should learn how relationships require work, how to manage expectations and that ‘good’ relationships do not just happen.

Young people who took part in a new study said relationship education would help them to develop better skills to manage communication and conflict. They said they would welcome lessons on how to manage different stages in relationships, how to sustain happy relationships, and how to end relationships that could not be sustained, and cope with the aftermath.

The interdisciplinary research, by Simon Benham-Clarke, Jan Ewing, Anne Barlow and Tamsin Newlove-Delgado from the University of Exeter, was carried out as part of the Beacon project, funded by the university’s Wellcome Centre for the Cultures and Environments of Health.

Experts conducted focus groups with 24 young people from the South West aged between 14 and 18 and ten relationship professionals. All recognised the importance of schools supporting young people to build healthy relationships.

Simon Benham-Clarke said: “Our research shows schools need improved support to run relationships education, including specialist expertise and resources, and guidance on signposting pupils to external sources of help. Positive relationship behaviours should be modelled, integrated and built on throughout curriculums nationally and reflected in a school’s ethos.”

“Those we surveyed highlighted the importance of teaching skills such as relating, communication, empathy, respect, conflict resolution and repair and ending relationships kindly and safely.”

Dr Newlove-Delgado said: “Young people saw schools as offering an unbiased and alternative perspective on relationships, particularly for those who might have more challenging backgrounds, however a desire was expressed for a greater focus in schools on how relationships ‘work’ rather than on sex education.”

“Participants also felt that talking about family and peer relationships should come first, building up to later discussions about romantic relationships in later years at school, with some highlighting links between patterns of relationship behaviour.”

“Some young people were concerned about whether education about romantic relationships could put people of their age under pressure if it were too early.”

Professor Barlow said: “Those we surveyed felt schools could improve relationship outcomes for pupils in other ways beyond the relationship education lesson, such as having someone to talk to, in person and in private. Others wanted signposting and information about sources of help outside the school setting.”

Dr Ewing said “While young people’s families were seen as the primary source of learning about healthy relationships, there was clear support for schools’ role to augment this, as not all families exhibit healthy relationships. Relationship professionals thought that there were key transition moments in life, getting married or having a baby, where people are receptive to learning relationship skills, but that schools had a critical role in teaching and embedding critical skills around initiating and maintaining a healthy relationship.”

There was strong support for relationships education to start early, preferably in primary schools, exploring what a healthy friendship and relating well to others looks like before moving onto romantic relationships, which would give young people vital life skills. Starting early, in primary schools and with counselling support where needed, was thought to be particularly important for young people whose parents were locked in conflict.

JOURNAL

BMC Public Health

DOI

10.1186/s12889-022-14802-5 

METHOD OF RESEARCH

Survey

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Learning how relationships work

ARTICLE PUBLICATION DATE

13-Dec-2022

Two fungi work together to kill fig trees

Peer-Reviewed Publication

NAGOYA UNIVERSITY

 

IMAGE: CERATOCYSTIS FICICOLA view more 

CREDIT: ZI-RU JIANG AND HISASHI KAJIMURA

In many countries, the number of fig trees have been declining. While there are numerous explanations, one key problem is fig-wilting disease. A recognized cause of this disease is a fungus, Ceratocystis ficicola, which is transmitted by an ambrosia beetle, Euwallacea interjectus. Now, a group from Nagoya University in central Japan has identified another fungus, Fusarium kuroshium, which is harmless by itself, but ravages fig trees when found together with C. ficicola.  

Along with known agents, such as C. ficicola, many other fungi are believed to be important in fig-wilting disease. These include F. kuroshium, a well-known infective agent of fig and avocado trees. As these fungi are frequently found on the heads, including a special organ for storing fungi, of wild and reared E. interjectus adult females, it has long been suspected that they are responsible for the spread of disease.  

To determine whether the fungi are related to the damage of the fig trees, Dr. Zi-Ru Jiang and Associate Professor Hisashi Kajimura of the Graduate School of Bioagricultural Sciences, Nagoya University, in partnership with the Hiroshima Prefectural Institute of Technology, Kobe University, and the Forestry and Forest Products Research Institute, inoculated fig saplings with various combinations of fungi collected from E. interjectus. As a control, they also included Neocosmospora metavorans, which is found in a wide range of plant hosts, including avocado and Robusta coffee. Some saplings received only one of the three fungi, and one group received a combination of F. kuroshium and C. ficicola.  

As expected, the saplings infected with C. ficicola wilted, whereas the other two groups infected with only N. metavorans or only F. kuroshium did not, suggestingthat these two fungi are not harmful to fig trees. However, in the combination group, the saplings wilted less than two weeks after infection and had a larger area of dead wood. It seems that F. kuroshium and C. ficicola worked together in a symbiotic way that accelerated wilting in the saplings. The findings were reported in Microorganisms.  

“A combination of the ambrosia beetle and its fungi may lead to symptoms of fig-wilting disease in the case of mass beetle attacks and decreased resistance in host trees. Therefore, understanding the relationship between C. ficicola and its symbionts may be useful in developing suitable disease control strategies,” explains Kajimura. “This study suggests that symbiotic fungi do not kill fig trees by themselves, but that synergistic effects are driven by their coexistence with companion fungi, and that they have a more detrimental effect on fig trees than the companion fungi alone. This fact leads to additional targets for control and provides important clues to improve integrated pest management methods in the future.” 

Cross cut stem surfaces of different fungal infections, note especially the discoloration caused by Ceratocystis ficicola as well as Fusarium kuroshium + C. ficicola (righthand red box).

CREDIT

Zi-Ru Jiang and Hisashi Kajimura

JOURNAL

Microorganisms

DOI

10.3390/microorganisms10101912 

ARTICLE TITLE

The role of mycangial fungi associated with ambrosia beetles (Euwallacea interjectus) in fig wilt disease: Dual inoculation of Fusarium kuroshium and ceratocystis ficicola can bring fig saplings to early symptom development

Warwick University to host UK’s most powerful Nuclear Magnetic Resonance instrument

A consortium led by the University of Warwick has been awarded £17M to procure the UK’s most powerful Nuclear Magnetic Resonance (NMR) instrument at 1.2 GHz. There are only seven such machines currently operating around the world. 

Grant and Award Announcement

UNIVERSITY OF WARWICK

A consortium led by the University of Warwick has been awarded £17M to procure the UK’s most powerful Nuclear Magnetic Resonance (NMR) instrument at 1.2 GHz. There are only seven such machines currently operating around the world.  The funds have been awarded to a consortium of six UK Universities through the UKRI Infrastructure Fund.  Other Universities in the consortium are Lancaster, Liverpool, Nottingham, Southampton and St Andrews. 

 

In the UK and at Warwick University, researchers are using NMR technology to improve green infrastructure by expanding their knowledge of how to make more efficient plant biofuels, to improve batteries and solar cells. The instrument will also be used in research on anti-microbial resistance and drug design and delivery.  Scientists from around the country will be able to use the facility and students at Warwick and other universities will gain invaluable experience on the state of the art NMR instrument enabling them to compete at the cutting edge of scientific research.

 

Professor Steven Brown, from the University of Warwick's Solid State NMR Group, commented: “It is exciting that Warwick has been selected as the site for this world-class NMR instrumentation. I look forward to working with the consortium partners and the UK community to deliver this world-class resource for UK science.” 

 

Professor Caroline Meyer, Pro-Vice Chancellor (Research) at the University of Warwick, said: “This instrument will provide the greatest resolution and sensitivity yet – allowing us to make scientific breakthroughs that will benefit us all as they improve our technology in a range of areas.”  

 

Jane Nicholson, Research Base Director at EPSRC, part of UK Research and Innovation said: “This national facility, one of only seven 1.2 GHz magnets in the world, will advance the study of all types of molecules.   

 

“The applications will be many and varied with the potential for new insights into areas such as materials for energy applications, catalysis, pharmaceutical research, synthetic biology and antimicrobial resistance.”  

 

Nuclear Magnetic Resonance instruments are used to analyse complex materials to work out their structure. This is done using magnets that are about one million times more powerful than the earth’s magnetic field. They work on the magnetic field of each atom in the material being investigated and provide detailed information on the atomic-level structure of that material.  

The 1.2 GHz NMR spectrometer will be housed in a new building and will create two new jobs for scientists. It builds upon current capability at 1.0 GHz at the Warwick-hosted UK High-Field Solid-State NMR National Research Facility. 

 

/ends 

PolyU researchers compile world’s first “atlas” of airborne microbes that provides an important new perspective for public health research

Peer-Reviewed Publication

THE HONG KONG POLYTECHNIC UNIVERSITY

 

IMAGE: THE RESEARCH TEAM ANALYSED THE BACTERIAL COMMUNITIES OF 370 INDIVIDUAL AIR PARTICULATE SAMPLES COLLECTED FROM 63 SITES AROUND THE WORLD, FROM GROUND LEVEL TO MOUNTAINTOPS, AS WELL AS FROM DENSELY POPULATED URBAN CENTRES TO THE ARCTIC CIRCLE. view more 

CREDIT: RESEARCH AND INNOVATION OFFICE, THE HONG KONG POLYTECHNIC UNIVERSITY

Bacteria are truly abundant across the Earth’s surface, from the soil to the oceans. The microbial population of the air that surrounds us is comparatively unknown, but a research expedition led by PolyU scientists is about to change that. After nearly a decade of effort, they have compiled a comprehensive map of the world’s airborne microbes, providing fresh insights into how these species interact with the surface environment – as well as their likely future changes.

A cubic metre of “empty” air contains 10,000 bacteria or more, and interest in the role of air as a habitat – not merely a conduit – for microbes has grown enormously since the start of the COVID-19 pandemic. In collaboration with researchers on the mainland and the US, the PolyU-led team spent around a year sampling airborne microbes across the world, from ground level to mountaintops. Combining their own results with the most accurate global data collected in past studies, they and their research partners compiled the first ever atlas of the global airborne microbiome.

The atlas provides a wealth of insights into the microbial communities floating above the ground. There is no doubt that the air is a unique harbour of bacterial life. Genetic analysis by the team showed that the core communities – the handful of species that form an outsized proportion of the microbe population – were not the same in the air as those in marine or soil ecosystems. In fact, even though the air is a free-flowing medium with seemingly no internal boundaries, these core bacterial communities are distinctly localised and stable.

The research team analysed the bacterial communities of 370 individual air particulate samples collected from 63 sites around the world, ranging from those at ground level (1.5 – 2 m high) to rooftops (5 – 25 m high) and high mountains (5,238 m asl), as well as from densely populated urban centres to the Arctic Circle, for a more diverse coverage in terms of altitudes and geographic regions.

Prof. Xiang-dong LI, Chair Professor of Environmental Science and Technology and Dean of Faculty of Construction and Environment of PolyU who led the research team, said, “We have verified that human activities have certainly changed the structure of microbiomes in the natural ambient air, particularly with a higher abundance of pathogenic bacteria in urban air. Having experienced the pandemic for three years, people now pay more attention to this invisible but influential microbial community. The research outcomes could be served as a critical reference for predicting planetary microbiome responses and the health impacts of inhalable microbiomes with future environmental changes.”

The researchers estimate that the total number of microbes occupying the sea or soil is thousands of times larger than those in the air. Nonetheless, the aerial diversity of microbes – known as “richness” – is just as high. This suggests that surface habitats directly contribute microbes to the air. Overturning previous assumptions, vegetation is not the main terrestrial source of airborne bacteria, and the Earth’s vast tracts of soil provide very small fraction. The crashing of waves, the shaking of leaves, and even frequent activities and constant respiration of animals and humans are bigger drivers of bacterial exchange between the surface and the air.

Macroscopic life, notably animals and plants, is most diverse in equatorial regions (consider, for example, warm and wet rainforests), and its diversity decreases closer to the poles. For microbes, the picture is more interesting – moving from the equator, diversity maximises at mid-latitudes before falling away again. This pattern was well established for terrestrial and aquatic microorganisms, but the new atlas confirms that it applies to the airborne microbiome, too. The authors surmise that the “bump” in diversity at mid-latitudes is caused by stronger sources of microbial input to those regions.

Overall, the researchers estimate that half of airborne bacteria originate from ground sources. Urban air has especially high rates of human-associated bacteria – some harmless, others pathogenic. Direct transfer of germs from people to air is not our only effect on the airborne microbial world. Broad-scale activities such as industrialisation disrupt natural environments and impact air quality. This weakens the environment’s “filter” effect on microbial structure, making the composition of airborne bacteria more affected by random processes – although weather still plays an important role too.

The close relationship between modern human activities and the microbes around us underscores the need to predict future changes accurately. The inhalable infectious bacteria that proliferate in cities are particularly of concern considering rapid urbanisation and our growing understanding of airborne contagion, spurred by COVID-19 research. Climate change is another impetus, given the marked effect of temperature on microbial richness, as revealed by the atlas. Hence, the study provides an invaluable resource and an important new perspective for future public health research.

The PolyU team collaborated with Prof. James M. TIEDJE, University Distinguished Professor at Michigan State University and scientists from mainland China in the study. The findings were published in the Proceedings of the National Academy of Sciences (https://www.pnas.org/doi/full/10.1073/pnas.2204465119), a peer-reviewed journal of the USA National Academy of Sciences.

  

The structure of globally distributed airborne bacterial communities. (A) Locations where air samples and environmental data were collected across the globe. (B) The number, proportion, and relative abundance of the global core OTUs compared with those of the remaining bacterial OTUs. (C) The taxonomic composition of the global core bacteria at the phylum and class level. (D) The global airborne bacterial community co-occurrence network. The connections (edges) stand for a strong (Spearman’s ρ > 0.6) and significant (p < 0.01) correlation. The nodes represent the combined OTUs with unique annotations for genus level in the datasets. The size of each node was proportional to the mean relative abundance across 370 samples. Nodes were colored by the phyla of the bacteria. (E) “Small-network” identification based on a “smallworldness” index and the average shortest path length of the global bacterial community network in air, marine, and soil environments. (F) Degree—the betweenness centrality plot of each node in the co-occurrence network. The nodes in red are viewed as keystone species. The size of the nodes shows the relative proportions of the OTUs in the total microbiome.

CREDIT

PNAS

JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2204465119 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Global airborne bacterial community—interactions with Earth’s microbiomes and anthropogenic activities

Scientists develop low-cost system to measure space weather without leaving the ground

Peer-Reviewed Publication

NAGOYA UNIVERSITY

 

IMAGE: AN ELECTRIC CIRCUIT BOARD OF THE MI SENSOR view more 

CREDIT: MASAHITO NOSÉ

A research team from the Institute of Space-Earth Environmental Research (ISEE) at Nagoya University in Japan used a sensor manufactured by Aichi Steel Corporation to build a magneto-impedance sensor magnetometer (MIM) that measures variations in the Earth’s geomagnetic field. Since geomagnetic fluctuations are closely related to phenomena taking place in outer space, researchers in upper atmospheric physics and space physics can use the MIM to determine the status of space weather from the ground without the use of satellites. They reported the results in the Journal of Geophysical Research: Space Physics.  

“In recent years, space travel by private citizens has become more common. In addition, the Japan-US-EU joint Gateway Projects to build a space station in lunar orbit have been launched,” explains lead author Masahito Nosé. “Therefore, we need more real-time space weather information to know what is happening in space to the safety and maintenance of spacecraft.”  

Although people often imagine space to be a vacuum, it is filled with space plasma, consisting of charged particles held in a hot gas. When these particles interact with the Earth's magnetic field, they cause ‘space weather’ effects, such as geomagnetic storms or space auroras, that can affect satellites, space stations, and astronauts. Despite the importance of monitoring space weather, it is difficult for a device to remain in space and continually monitor the space environment. On the other hand, environmental changes that occur in space can be observed from the ground because they are transmitted as electromagnetic waves along the Earth's magnetic field. Unfortunately, standard approaches to making such observations have struggled because it is necessary to capture weak magnetic field fluctuations, often a fraction of the size of the Earth's magnetic field.  

Associate Professor Nosé of ISEE, in collaboration with Aichi Steel Corporation, has developed a low-cost system to measure the Earth's magnetic field using the magneto-impedance (MI) effect, which was discovered in 1993 at Nagoya University. Although the Aichi Steel Corporation sensor originally measured only the AC components of the geomagnetic field, the researchers implemented a magnetic-flux locked loop circuit in the MI sensor to extend the measurement range.  

The newly developed MIM is suitable for observations of phenomena such as storms generated by an enhancement of the solar wind dynamic pressure and long-period geomagnetic pulsations. It is also lightweight, power efficient, and comparatively inexpensive. This should make it easier to construct a multi-point observation network, which could speed up space environment monitoring and space weather research.  

Nosé installed the MIM for a month of continuous observation at the Mineyama observatory for experimental field observations near Kyoto, Japan. Although weak geomagnetic fluctuations are difficult to capture, he identified those approximately 1/100,000th the size of the earth's magnetic field.  

“Various phenomena that occur in space are transmitted as electromagnetic waves in a plasma along the magnetic field of the Earth, causing weak geomagnetic fluctuations on the ground. Therefore, using the magnetic sensor developed in this research, it is possible to investigate phenomena occurring in space without leaving the ground,” explains Nosé. “These geomagnetic fluctuations reflect the electromagnetic energy in space that is related to phenomena such as the generation of auroras and the weight and density of plasma in space. We expect that detailed analysis will lead to the development of real-time monitoring of the space environment and the advancement of space weather research.” 

Funding: This study was supported by the Japan Society for the Promotion of Science (JSPS), Grant-in-Aid for Scientific Research (B) (21H01147), Challenging Research (Pioneering) (Grant 17K18804), and Grant-in-Aid for Specially Promoted Research (Grant 16H06286) as well as Ito Kagaku Shinkou Kai and Yamada Science Foundation. 

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JOURNAL

Journal of Geophysical Research Space Physics

DOI

10.1029/2022JA030809 

ARTICLE TITLE

Application of Magneto-Impedance (MI) Sensor to Geomagnetic Field Measurements