MUTUAL AID

Crops grown together cooperate better in just two generations

Crops bred for single-species systems rapidly adapt to growing alongside multiple species, and specific breeding may further enhance cooperation and improve productivity

Reports and Proceedings

ELIFE

The findings provide preliminary evidence about how quickly crops bred for single-species, or 'monoculture', settings can adapt to growing with other crop species. 

Growing multiple food crops together is a more sustainable farming practice mimicking highly productive wild plant communities. This process, known as intercropping, takes advantage of complementary features of different types of crops to maximise production and minimise the need for fertilisers and other environmentally harmful practices. For example, indigenous people in North America have long grown corn, beans and squash together to maximise the yield of each plant and reduce the need for watering or fertiliser. 

“Most commercial crops, however, have been bred for traits that make them highly productive in single-crop settings,” explains lead author Laura Stefan, a former PhD student at ETH Zurich and now a postdoctoral researcher at Agroscope, the Swiss Confederation’s Institute for Agricultural Research. “These crops may not be well suited for growing in multi-crop systems, which may reduce the benefits of intercropping.” 

To learn more about different crops’ ability to adapt, the team grew wheat, oat, lentil, flax, camelina and coriander species in small plots. The plots included 13 combinations of two species, four mixtures of four different species, plants growing individually or in single-species parcels, in fertilised or unfertilised plots. The team repeated the experiments for three consecutive years, each year using seeds collected from the plots of the previous year to assess the generational effects of growing in different systems. In the third year, they measured the plants' traits and productivity. 

They found that plants grown in the same multi-crop setting for two generations adapted to compete less and cooperate more with each other. However, the yield advantage of these multispecies crops compared to monoculture crops was only increased in fertilised plots. Over two generations, plants grown together in either monocultures or mixed-species plots grew taller. They also produced “cheaper”, or thinner leaves, indicating a growth strategy associated with rapid biomass production.

“Our study shows that annual crops rapidly adapt to be more cooperative over just two generations, but this doesn’t lead to increased yield advantages without fertiliser,” says co-author Nadine Engbersen, who worked on the study as a PhD student at the Institute of Agricultural Sciences at ETH Zurich, Switzerland. “Unexpectedly, the plants all grew to have more similar traits rather than specialising to fill a unique niche.” 

The authors suggest that the short time frame of the study – over just three years – may explain why more differentiation did not occur. It is unlikely that many genetic changes happened during that time. However genetic selection of particular genotypes might have occurred for those species with existing genotypic variation. Furthermore, epigenetic modifications that turn genes on or off may explain some of the observed plant adaptations. Microbes or nutrient resources passed from one plant generation to the next via seeds may also explain some of these rapid adaptations. 

Longer-term studies may observe more adaptations caused by genetic mutations or genetic recombination, the rearrangement of plant DNA sequences. The current results suggest selective breeding could give rise to traits that optimise cooperation and yield in multispecies plots.

“Our findings have important implications for the shift to more diversified agriculture,” concludes senior author Christian Schöb, Head of the Agricultural Ecology Group, previously at ETH Zurich and now at the University Rey Juan Carlos. “They suggest breeding plants to grow in mixed-species plots may further improve yields and reduce the need for fertiliser and other harmful practices.” 

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About eLife

 

eLife transforms research communication to create a future where a diverse, global community of scientists and researchers produces open and trusted results for the benefit of all. Independent, not-for-profit and supported by funders, we improve the way science is practised and shared. From the research we publish, to the tools we build, to the people we work with, we’ve earned a reputation for quality, integrity and the flexibility to bring about real change. eLife receives financial support and strategic guidance from the Howard Hughes Medical Institute, Knut and Alice Wallenberg Foundation, the Max Planck Society and Wellcome. Learn more at https://elifesciences.org/about.

To read the latest Ecology research published in eLife, visit https://elifesciences.org/subjects/ecology.

And for the latest in Plant Biology, see https://elifesciences.org/subjects/plant-biology.

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JOURNAL

eLife

DOI

10.7554/eLife.77577 

ARTICLE TITLE

Rapid transgenerational adaptation in response to intercropping reduces competition

ARTICLE PUBLICATION DATE

13-Sep-2022

Little Ice Age study reveals North Atlantic reached a tipping point

Peer-Reviewed Publication

UNIVERSITY OF EXETER

 

IMAGE: OCEAN QUAHOG CLAM view more 

CREDIT: PAUL KAY

Scientists have used centuries-old clam shells to see how the North Atlantic climate system reached a "tipping point" before the Little Ice Age.

The Little Ice Age – a period of regional cooling, especially in the North Atlantic – lasted several centuries, ending in about 1850.

A long-standing theory suggests initial cooling in this period was sustained by "sea-ice to ocean feedbacks" – sea ice expanded and this slowed ocean currents which in turn reduced the flow of warm water from the south.

The new study, by the University of Exeter, used the shells of quahog clams – which can live for several hundred years – to understand how the ocean has evolved and responded to external changes over recent centuries.

The findings show that the North Atlantic climate system destabilised and lost resilience (the ability to recover from external changes) prior to the Little Ice Age, possibly causing it to "tip" into a new, colder state.

And the researchers say the North Atlantic could be approaching a new tipping point, with major consequences for the region's climate.

With scientists warning that multiple tipping points may now be approaching worldwide due to human-driven climate change, the study helps us understand when and how tipping points are triggered.

"One way to tell that a system is approaching a sudden transition is that it becomes slow to respond to perturbations (external changes)," said lead author Beatriz Arellano-Nava, of Exeter's Global Systems Institute.

"In other words, a system loses the ability to return to its average state, and can instead 'tip' into a new state."

"In the case of the North Atlantic prior to the Little Ice Age, this loss of resilience made the system vulnerable to an abrupt switch, potentially heralding the transition to Little Ice Age conditions" said Dr Paul Halloran, who co-led the research.

The new study warns that vulnerability of the North Atlantic system is a critical issue today, with recent analysis suggesting it has destabilised during the last century and might be approaching a tipping point.

"Our latest analysis suggests that the system of ocean currents in the northern North Atlantic could be at risk of a tipping point again now due to global warming, leading once again to abrupt climate change over Europe," said Professor Tim Lenton, Director of the Global Systems Institute.

Analysis of clam shells focussed on oxygen and carbon isotopes and shell growth – all of which can be used as measures of environmental variability.

The study was funded by the European Union’s Horizon 2020 research and innovation programme.

The paper, published in the journal Nature Communications, is entitled: "Destabilisation of the Subpolar North Atlantic prior to the Little Ice Age."

Climate tipping points – and the power of "positive tipping points" to tackle the climate crisis – are being discussed at a conference in Exeter this week (12-14 September). To find out more, visit: https://global-tipping-points.org/

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JOURNAL

Nature Communications

DOI

10.1038/s41467-022-32653-x 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Destabilisation of the Subpolar North Atlantic prior to the Little Ice Age

Researchers develop a new way to see how people feel about Artificial Intelligence

Peer-Reviewed Publication

KAVLI INSTITUTE FOR THE PHYSICS AND MATHEMATICS OF THE UNIVERSE

 

IMAGE: FIGURE 1: ANSWERS FROM RESPONDENTS IN JAPAN, US, AND GERMANY SEPARATED INTO ETHICAL, LEGAL AND TRADITIONAL ANSWERS. BY MEANS OF SEGMENTATION, THE RESPONSES CAN BE COLOR-CODED ACCORDING TO WHETHER THE RESPONDENT’S ANSWER WAS POSITIVE (LIGHT BLUE), NEGATIVE (ORANGE), CONCERNED ABOUT LEGAL ISSUES (NAVY) OR NOT CONCERNED ABOUT LEGAL ISSUES (CRIMSON). view more 

CREDIT: IKKATAI ET AL./KAVLI IPMU

People in Japan, US, and Germany show different concerns regarding Artificial Intelligence (AI) being used in entertainment, shopping services, or to help find criminals, reports a new study in AI and Ethics.

Japanese people tended to report more concern in AI used to fight crime, while Germans and Americans tended to report more concern over the ethical and social aspects of using AI in entertainment, it was found.

“We found there is a difference in the AI and ELSI levels of understanding between countries. I think it will become important to carry out thorough discussions about the legal and policy issues surrounding AI,” said first author and Kanazawa University Associate Professor Yuko Ikkatai.

AI is currently being used in a wide range of fields, which has raised positive and negative attitudes in the general public. Ethics policies differ from country to country, such as in Japan where guidelines emphasize regulation of AI and decreasing people’s concerns, while in the US they emphasize the need to maximize social benefits of AI and mention long-term risks, while in Europe the guidelines emphasize the rights and responsibilities of people. 

A research team led by Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) Professor Hiromi Yokoyama, Ikkatai, and University of Tokyo Institute for Physics of Intelligence Assistant Professor Tilman Hartwig, noticed the ethical attitudes towards AI, a universal, advanced technology, varied between countries. The researchers say recognizing public attitudes about AI in different countries will become increasingly important before deploying new AI technologies.

Their study involved carrying out an online survey in Japan, the United States, and Germany, asking respondents to look at four different AI scenarios and answer 3 questions about each of them, taking into consideration the Ethical, Legal, and Social Issues (ELSI). The first scenario involved using AI for AI-generated singers, the second scenario, AI customer purchases, the third, AI autonomous weapons, and lastly AI predictions of criminal activities. About 1000 respondents in each country were chosen, reflecting their own country's population for age, gender and location.

After analyzing their results, the researchers were able to separate responses into four groups: people with optimistic views, people with negative views, people concerned about legal issues, and those not concerned about legal issues. The team have named this the AI and ELSI segment.

The researchers had previously developed an octagonal visual metric, analogous to a rating system, which could be useful to AI researchers who wished to know how their work might be perceived by the public. Developing the AI and ELSI segment was because the researchers found the octagonal visual metric to be limited in versatility when applied to new technologies other than AI. 

In the team's most recent study, they found that overall, the older the respondent, the more concern they had about AI and ELSI issues, while respondents more familiar with AI said they were most concerned about the legal issues.

In regard to each scenario, German and US respondents were most concerned about ethical and social issues regarding AI-generated singers. 

About using AI for shopping purposes, German respondents were most concerned about the ethical issues, while Japanese respondents were most concerned about the legal issues.

In regard to AI autonomous weapons, Japanese and German respondents were most concerned about ethical issues, and Japanese respondents were also most concerned about the social and legal issues. 

Finally, in regard to using AI to capture criminals, US respondents were most concerned about the ethical, social and legal issues.

"It is exciting that we can segment the replies so clearly into four groups, and the most distinctive feature is the perception of AI legal issues. This is robust amongst the three countries and shows that communication about AI-related laws and policies is very important," said Hartwig.

Details of their study were published in AI and Ethics on September 1.

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JOURNAL

AI and Ethics

DOI

10.1007/s43681-022-00207-y 

ARTICLE TITLE

Segmentation of ethics, legal, and social issues (ELSI) related to AI in Japan, the United States, and Germany

A switch telling the brain when to learn and when to remember

Peer-Reviewed Publication

INSTITUT PASTEUR

 

IMAGE: VIRTUAL REALITY ENVIRONMENT SEEN BY MICE view more 

CREDIT: © RUY GÓMEZ-OCÁDIZ, CHRISTOPH SCHMIDT-HIEBER, INSTITUT PASTEUR

The memory system alternates between periods of learning and remembering. These two functions are controlled by different neural circuits. Using an animal model, scientists from the Institut Pasteur recently identified a neural signal in the hippocampus, a brain region essential for forming and recalling memories, that enables the brain to alternate between remembering and learning modes. The findings were published in the journal Nature Communications on July 15, 2022.

As we go about our lives, our brain continually remembers information that we have learnt in the past and uses it to make sense of the world in the present. However, we also often encounter objects and events that we have never experienced before, and then the brain needs to be ready to learn. These two essential functions of our brain’s memory system, learning and remembering, seem to constantly compete against each other. "How the brain finds the balance between these two opposing processes is a question that has fascinated neuroscientists for a long time," explains Christoph Schmidt-Hieber, head of the Neural Circuits for Spatial Navigation and Memory Laboratory at the Institut Pasteur.

Christoph Schmidt-Hieber’s research group has recently tackled this problem by designing an experiment in which mice explore virtual reality environments as their brains are recorded. "We realized that the main obstacle to studying how the brain reacts to novelty was physical reality itself!" explains Ruy Gómez-Ocádiz, a PhD student in the laboratory and first author of the study. It is almost impossible to study the effect that absolute novelty has on the brain in a traditional experiment, because one would need to instantly change everything that an animal is perceiving. "We could easily overcome this problem if only we could ‘teleport’ a mouse to a new room as we record its brain. This might sound like science fiction, but virtual reality technology allowed us to do precisely that," continues Ruy Gómez-Ocádiz.

The scientists designed a video game in which mice learn to explore a virtual 'world' and get sugar rewards when they correctly follow the rules of a simple game. While mice were engaged in playing the video game, the researchers recorded the activity of neurons in the hippocampus, a brain region that is essential for forming and recalling memories.

Using this innovative approach, they discovered an electric signal in the hippocampus that appears at the precise moment when the animal is teleported to a new virtual world. The signal is emitted by granule cells and triggered by novelty. It induces a transition from a neural state of memory to a state of learning.

Teaming up with physicists from the École normale supérieure, Université PSL and the CNRS, the scientists then developed a computational model suggesting how such a novelty signal may work as a switch to enable the brain to alternate between remembering and learning modes depending on the information present in the environment. "The discovery of this novelty signal in the hippocampus provides exciting new clues to understand how the brain finds the necessary equilibrium between formation of new memories and recall of familiar ones," concludes Christoph Schmidt-Hieber.

The study was funded by the institutions mentioned above, the European Research Council (ERC) and the French National Research Agency (ANR).

 

Observation of the dentate gyrus in the hippocampus of a mouse model. The cell nuclei are stained in blue (DAPI). Recording of the activity of a neuron shown in green (biocytin-filled). Image width ~1mm.

CREDIT

© Ruy Gómez-Ocádiz, Christoph Schmidt-Hieber, Institut Pasteur, 2022; CC BY-NC-ND 4.0

Source

A synaptic signal for novelty processing in the hippocampus, Nature Communications, 15 juillet 2022

Ruy Gómez-Ocádiz 1,2,4, Massimiliano Trippa3, Chun-Lei Zhang 1, Lorenzo Posani 1,5, Simona Cocco 3, Rémi Monasson3 & Christoph Schmidt-Hieber 1

1 Institut Pasteur, Université Paris Cité, Neural Circuits for Spatial Navigation and Memory, Department of Neuroscience, F-75015 Paris, France.
2 Sorbonne Université, Collège Doctoral, F-75005 Paris, France.
3 Laboratory of Physics of the École Normale Supérieure, PSL Research and CNRS UMR 8023, Sorbonne Université, Université de Paris, F-75005 Paris, France.
4 Present address: Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden.
5 Present address: Center for Theoretical Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.

https://www.doi.org/10.1038/s41467-022-31775-6

---

JOURNAL

Nature Communications

DOI

10.1038/s41467-022-31775-6 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

A synaptic signal for novelty processing in the hippocampus

Golden Goose Award honors 11 researchers for unusual discoveries that greatly benefit society

These scientific breakthroughs led to the development of a bladeless LASIK procedure, paper microscopes, and the discovery of a non-opioid pain reliever hidden in the venom of cone snails

Grant and Award Announcement

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

 

IMAGE: THIS YEAR'S AWARDEES DISCOVERED A NON-OPIOID PAIN RELIEVER, HIDDEN IN THE VENOM OF TINY CONE SNAILS, WHICH GREATLY DECREASES PAIN FOR PATIENTS WITH CHRONIC ILLNESSES WHILE HELPING RESEARCHERS DEVELOP NEW WAYS TO MAP THE BODY’S NERVOUS SYSTEM. view more 

CREDIT: THE GOLDEN GOOSE AWARD

On September 14, 2022, the American Association for the Advancement of Science (AAAS), the world’s largest multidisciplinary scientific society, will host the 11th annual Golden Goose Award ceremony, a celebration of federally funded research that unexpectedly benefits society. This year's awardees, three international, multi-institutional teams, discovered:

• A novel approach to corrective eye surgery, bladeless LASIK is now considered the standard in the field and used by millions — resulting from an accidental laser injury.
• A way to construct a low-cost, high-performing paper microscope that scientists can use to diagnose diseases and expand science education in remote areas, making science accessible worldwide.
• A non-opioid pain reliever, hidden in the venom of tiny cone snails, which greatly decreases pain for patients with chronic illnesses while helping researchers develop new ways to map the body’s nervous system.

The Golden Goose Award spotlights scientific research that may have appeared obscure, sounded funny, or for which the results were unforeseen at the outset but ultimately, and often serendipitously, led to breakthroughs. This year, the award comes on the heels of the U.S. Congress passing and President Biden signing the bipartisan and historic CHIPS and Science Act. This new law reauthorizes key federal agencies whose projects will propel discovery, build on our strengths, and show what American investment, intellect, ingenuity and risk-taking can accomplish — precisely the type of innovation the Golden Goose Award honors. 

“The Golden Goose Award reminds us that potential discoveries could be hidden in every corner and illustrates the benefits of investing in basic research to propel innovation,” said Sudip S. Parikh, chief executive officer at AAAS and executive publisher of the Science family of journals. “AAAS is honored to elevate this important work since the award’s inception, and we thank Representative Cooper for his tireless leadership and dedicated support to this award and the scientific community.”

U.S. Representative Jim Cooper (D-TN), often referred to as “Father Goose,” will retire from Congress at the end of this term. He conceived of the award as a strong counterpoint to criticisms of basic research as wasteful federal spending, such as the late Sen. William Proxmire’s (D-WI) Golden Fleece Award, leading to a coalition of business, university, and scientific organizations establishing the award in 2012. Thanks to his legacy, the award will continue to elevate the importance of recognizing basic science that ultimately improves people’s quality of life.

“It has been an honor to watch the Golden Goose Award grow over the past decade, while highlighting the stories of incredible scientists and innovators in a range of fields. Remarkable scientific discoveries – and the people behind them – are as important as ever. Congratulations to this year’s awardees,” said Cooper.

“For years, the Golden Goose Award has highlighted amazing breakthroughs in scientific research thanks to key federal investments. I am pleased to join the Golden Goose Award family this year and grateful for AAAS’ support for the CHIPS and Science Act. This historic investment in science and technology will bolster our national security and our economy,” said Senator Todd Young (R-Ind.), the newest member of the Golden Goose Award’s bipartisan group of congressional supporters.

This year’s awardees are:

Ron Kurtz (RxSight), Tibor Juhasz (ViaLase), Detao Du (Rayz Technologies), Gerard Mourou (Ecole Polytechnique), and Donna Strickland (University of Waterloo)
How a Lab Incident Led to Better Eye Surgery for Millions of People

Nearly 30 years ago, a graduate student at the University of Michigan’s Center for Ultrafast Optical Science (CUOS) experienced an accidental laser injury to his eye. Fortunately, his vision was not severely affected. However, the observation of the very precise and perfectly circular damage produced by the laser led to a collaboration. Eight years later, that group of researchers developed of a bladeless approach to corrective eye surgery. The new procedure, also known as bladeless LASIK, uses a femtosecond laser rather than a precision scalpel cut into the human cornea before it is reshaped to improve the patient’s vision.

This year's awardees discovered a novel approach to corrective eye surgery, bladeless LASIK is now considered the standard in the field and used by millions — resulting from an accidental laser injury.

CREDIT

The Golden Goose Awards

Manu Prakash (Stanford University) and Jim Cybulski (Foldscope Instruments Inc.)
Foldscopes and Frugal Science: Paper Microscopes Make Science Accessible

While researching in remote areas of India and Thailand, a technical challenge piqued Manu Prakash’s curiosity. In certain areas of the world, transport, training, and maintenance barriers can make state-of-the-art microscopes inaccessible. Prakash found a potential solution in a decidedly un-technical material: paper. Using principles of origami applied to printer paper, matchboxes, and file folders, Prakash and graduate student Jim Cybulski designed a paper microscope known as the Foldscope that can achieve powerful magnification with materials that cost less than $1 to manufacture. Today, just over a decade later, two million Foldscopes have been distributed in over 160 countries and have been used to diagnose infectious diseases, diagnose new species, and identify fake drugs, among many other applications.

This year's awardees discovered a way to construct a low-cost, high-performing paper microscope that scientists can use to diagnose diseases and expand science education in remote areas, making science accessible worldwide.

CREDIT

The Golden Goose Awards

Craig T. Clark (in memoriam), Lourdes J. Cruz (University of the Philippines), J. Michael McIntosh (University of Utah; George E. Wahlen VA Medical Center), and Baldomero Marquez Olivera (University of Utah)
Tiny Snail, Big Impact: Cone Snail Venom Eases Pain and Injects New Energy into Neuroscience

Impeded by supply chain issues while conducting DNA research in the Philippines, Lourdes Cruz and Baldomero Olivera began examining cone snails, a group of highly venomous sea mollusks which happened to be in abundant supply along the country’s coastal waters. Several decades and countless airline miles later, and with the help of then-undergraduate students Craig Clark and Michael McIntosh, the team discovered the raw material for a non-opioid pain reliever and a powerful new tool for studying the central nervous system, all hidden in the cone snail’s potent venom.

The Golden Goose Award is pleased to welcome several new sponsors this year, including Wiley, a global publishing company supporting researchers to communicate discoveries that make a difference, and Google.

Air pollution may spur irregular heart rhythms in healthy teens

Teens’ hearts may skip a beat within two hours after air pollution exposure, according to a study in the Journal of the American Heart Association

Peer-Reviewed Publication

AMERICAN HEART ASSOCIATION

DALLAS, Sept. 14, 2022 — Breathing particulate matter (i.e., tiny particles suspended in the air) air pollution may trigger irregular heart rhythms (arrhythmias) in healthy teenagers, according to new research published today in the Journal of the American Heart Association, an open access, peer-reviewed journal of the American Heart Association.

While the negative cardiovascular effects of air pollution on adults has already been established, this study is the first to assess the impact of air pollution on teenagers in the general population.

“While relatively rare, irregular heart rhythms can lead to sudden cardiac death in otherwise healthy adolescents and young adults. Our findings linking air pollution to irregular heart rhythms suggest that particulate matter may contribute to the risk of sudden cardiac death among youth,” said Fan He, Ph.D., lead author of the study and an instructor in public health sciences at the Penn State College of Medicine in Hershey, Pennsylvania. “Since childhood and adolescent cardiovascular conditions can track into adulthood and affect risk of major cardiovascular disease later in life, identifying modifiable risk factors of cardiac arrhythmia that may cause sudden cardiac death among adolescents should be of great public interest.”

The study examined the impact of breathing fine particulate matter on heart rhythms of adolescents. Fine particulates (PM2.5) are less than 2.5 microns in size and can easily be inhaled deep into the lungs and even enter the bloodstream. Particles smaller than 2.5 microns are usually related to fuel combustion, such as particles from car exhaust or wildfires. Once inhaled, the pollutants irritate the lungs and blood vessels around the heart, and previous research has suggested that over time, pollutants increase the process of disease in the arteries.

The investigators analyzed the impact of breathing particulate matter pollution on two types of irregular heart rhythms characterized by premature contraction in the heart muscle, often described as a “skipped heart beat.” In premature atrial contractions (PAC), the heartbeat originates from the atria (top chambers of the heart). This usually causes no symptoms or harm, however, frequent, premature atrial contractions have been related to an increased risk of atrial fibrillation – a severe form of arrhythmia in which the top chambers quiver instead of beating effectively, thereby raising the risk of blood clots and stroke. Premature ventricular contractions (PVC) occur when the heartbeat originates from one of the ventricles (lower chambers of the heart). These also raise the risk of later heart attack, stroke, heart failure or sudden cardiac death.

If premature contractions cause no symptoms, they are not treated. However, if they occur often and lead to frequently feeling a skipped heartbeat, fast heartbeat or a pounding heart, treatment with medications, implantable devices or procedures may be advised.

Researchers analyzed health data for 322 adolescents (average age 17 years; 56% males; 79% non-Hispanic white teens) living in central Pennsylvania who participated in a follow-up evaluation in the Penn State Child Cohort study. That study, conducted between 2002 and 2006, initially recruited children ages 6 to 12 years. The data analyzed in this study reviewed results from the follow-up evaluation nearly 7.5 years later (2010-2013). This group of children were free of major cardiovascular conditions and considered at low risk for irregular heart rhythms. In the follow-up study, the researchers simultaneously measured exposure to fine particulate matter in the air each teen breathed (using a device called a nephelometer) for 24 hours and EKG tracings of each teen’s heart rhythms via a small wearable device called a Holter monitor.

The average PM2.5 concentration measured in the study was approximately 17 micrograms of particulate matter per cubic meter of air (µg/m3) per day, which is well-below the health-based air quality standard of 35 µg/m3 established by the U.S. Environmental Protection Agency (EPA).

The study found:

• 79% of the participants had at least one irregular heart rhythm during the 24-hour study period. Of that group, 40% had only premature atrial contractions, 12% had only premature ventricular contractions, and 48% had both.

• A 5% increase in the number of premature ventricular contractions within two hours of exposure was noted for each increase of 10 µg/m3 in PM2.5.
• No association was found between the concentration of particulate matter and the number of premature atrial contractions.

“It is alarming that we were able to observe such a significant impact of air pollution on cardiac arrhythmias when the air quality remained well within the health-based standards established by the EPA. It may suggest that adolescents who live in highly polluted areas such as inner cities are at even higher risk,” He said.

The results were consistent with data previously obtained in adults using similar methods from these researchers and others, although the increase in premature ventricular contractions was even higher in adults. Reducing the risk of irregular heart rhythms in adolescents may reduce their risk of developing heart disease as adults, according to the study authors.

“Our study found that air pollution increases the risk of cardiovascular diseases and sudden cardiac death, even among healthy adolescents,” He said. “Protective measures, such as wearing masks and avoiding vigorous physical activities, may be warranted on days that particulate matter concentration is high, especially during early morning rush hours.”

The most effective way to reduce everyone’s exposure to air pollution is by supporting more robust national-level air quality regulations, said American Heart Association volunteer expert Robert D. Brook, M.D., FAHA, professor of medicine at Wayne State University in Detroit. Brook has co-authored several American Heart Association scientific statements on air pollution.

“PM2.5 levels have fallen dramatically since the 1970s-80s due to regulations that have been unquestionably linked to improved health effects and life expectancy,” Brook said. “We outlined in a recent AHA scientific statement, titled Personal-Level Protective Actions Against Particulate Matter Air Pollution Exposure, strategies and activity or behavioral changes that may reduce pollution exposure, such as portable air cleaners, facemasks, respirators and exercising during non-peak hours. However, there have been no studies to show these measures can actually prevent adverse clinical health effects such as heart attacks.”

According to a 2020 American Heart Association policy statement citing a global study, ambient air pollution is widely recognized as a significant contributor to cardiovascular disease and death. In 2017, exposure to particulate air pollution was estimated to be associated with more than 7 million premature deaths and the loss of 147 million healthy life-years globally. The Association recommends further development of evidence-based policy approaches, continued investment in research and greater innovation and transformational partnerships to reduce the cardiovascular burden of ambient air pollutants in the U.S.

“The most interesting and significant aspect of this study is clearly that the results were found in healthy young adolescents,” Brook said. “The study adds support for the concern that even healthy young people are not immune to adverse cardiovascular responses to PM2.5 and at exposure levels within National Ambient Air Quality Standards for 24 hours established by the EPA. It is plausible that the findings help explain the potential reason for the time of onset of arrhythmias and even sudden death in some susceptible young people.”

Dr. He and colleagues are currently evaluating the impact of air pollution on other markers of cardiac electrical activity.

This study was limited in not being able to analyze the impact of air pollution on different subtypes of premature ventricular contractions, which may help cardiologists better understand how pollution impacts heart function. Results from this study in adolescents may not be generalizable to younger children.

Co-authors are Jeff D. Yanosky, Sc.D.; Julio Fernandez-Mendoza, Ph.D.; Vernon M. Chinchilli, Ph.D.; Laila Al-Shaar, Ph.D.; Alexandros N. Vgontzas, M.D.; Edward O. Bixler, Ph.D.; and Duanping Liao, M.D., Ph.D.

The study was funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health, and the Penn State Clinical and Translational Science Institute.

Studies published in the American Heart Association’s scientific journals are peer-reviewed. The statements and conclusions in each manuscript are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. The Association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific Association programs and events. The Association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and biotech companies, device manufacturers and health insurance providers and the Association’s overall financial information are available here.

Additional Resources:

• Multimedia is available on the right column of release link: https://newsroom.heart.org/news/air-pollution-may-spur-irregular-heart-rhythms-in-healthy-teens?preview=d83a43305a98115eac345aa64a2dab63
• After Sept. 14, view the manuscript online.
• AHA health information: Air Pollution and Heart Disease, Stroke
• AHA health information: About Arrhythmia
• AHA news release: Reduced air pollution in U.S. during pandemic shutdown linked to fewer heart attacks (Nov. 2021)
• AHA news release: Air pollution linked to high blood pressure in children; other studies address air quality and the heart (May 2021)
• Follow AHA/ASA news on Twitter @HeartNews
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About the American Heart Association

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JOURNAL

Journal of the American Heart Association

DOI

10.1161/JAHA.122.026370 

Are we missing a crucial component of sea-level rise?

Peer-Reviewed Publication

STANFORD UNIVERSITY

Recent efforts using computational modeling to understand how melting ice in Antarctica will impact the planet’s oceans have focused on ice-sheet geometry, fracture, and surface melting – processes that could potentially trigger or accelerate ice-sheet mass loss. Now, researchers have identified an additional process that could have a similarly significant effect on the ice sheet’s future: thawing of the bed, known as basal thaw, at the interface of the land and the miles-thick ice sheet above it.

The new study identifies areas that are not currently losing large amounts of mass but could be poised to match some of the largest contributors to sea-level rise – such as Thwaites Glacier – if they thawed. Antarctica is roughly the size of the United States, and the susceptible regions comprise an area greater than California. The research was published Sept. 14 in Nature Communications.

“You can’t necessarily assume that everywhere that’s currently frozen will stay frozen,” said senior study author Dustin Schroeder, an associate professor of geophysics at the Stanford Doerr School of Sustainability. “These regions may be under-appreciated potential contributors.”

Unusual suspects

The simulations were built on recent theoretical work showing that basal thaw could occur over short time scales. Using numerical ice sheet models, the study co-authors tested hypotheses about whether the onset of such thaw could lead to significant ice loss within a 100-year period. They found that triggering thaw led to mass loss in regions of the ice sheet that are not usually associated with instability and sea-level contributions at that time scale.

“There really has been little to no continental-wide work that looks at the onset of thawing – that transition from frozen ice to ice at the melting point, where a little bit of water at the bed can cause the ice to slide,” said lead study author Eliza Dawson, a PhD student in geophysics. “We were interested in learning how big an effect thawing could have and what regions of the ice sheet were potentially most susceptible.”

The researchers modeled temperature changes at Antarctica’s base according to shifts in friction caused by the ice sheet sliding over the land beneath it. The simulations revealed that in East Antarctica, which is currently considered a relatively stable region compared to West Antarctica, the Enderby-Kemp and George V Land areas would be most sensitive to thawing at their beds. Within George V Land, they also highlighted the Wilkes Basin as capable of becoming a leading sea-level contributor if thawing were to occur – a feature comparable in size to the rapidly evolving and likely unstable Thwaites Glacier in West Antarctica.

“The whole community is really focusing on Thwaites right now,” said Schroeder, who is also an associate professor of electrical engineering. “But some of the regions that are the usual suspects for big, impactful changes aren’t the most provocative and impactful areas in this study.”

Temperature matters

Because of Antarctica’s location and extreme conditions, information about the ice sheet is sparse. Even less is known about the land beneath its frozen façade.

“Measuring the bed is a massive effort in these remote places – we have the technology to do it, but you really need to pick the spot, and sometimes it takes years, and field camps, and special equipment to go do that,” Schroeder said. “It’s difficult and expensive.”

To fill in information gaps, the researchers relied on the physics of how ice slides – how changes in temperature affect the way the ice sheet flows and evolves. In follow-on work, the authors plan to develop and apply radar-based analysis approaches to study the temperature of the ice sheet bed in these critical areas.

“You need to know the regions where it matters, and that’s the transformative contribution of Eliza’s paper,” Schroeder said. “It asks these broad questions: Does this matter? And if it matters, where? We hope this approach gives the community some priorities into where to look and why, and to avoid going down blind alleys.”

Sleeping giants?

Scientists do not currently know what forces are most capable of triggering thawing at the bed in the potentially susceptible regions identified in this study – or how soon they may be able to do so. One possible driver could be changing ocean conditions, which is the case elsewhere in Antarctica.

“Warm ocean water does not necessarily reach these East Antarctica regions as it does in parts of West Antarctica, but it’s nearby, so there’s potential that could change,” Schroeder said. “When you consider the recent theoretical work showing that thermal processes at the bed can be easy to activate – even spontaneous – it makes near-term thawing of the ice-sheet bed seem like a far easier switch to flip than we’d thought.”

The study shows that measuring, understanding, and modeling the temperature at the base of ice sheets is important for understanding our future, as the biggest uncertainty in sea-level rise projections is the contribution from processes that can shift the behavior of massive ice sheets like Greenland and Antarctica.

“Follow-on work will be needed to take a closer look at these regions that this paper identified,” Dawson said. “Showing that thawing at the bed can result in mass loss from the ice sheet is a process that the community needs to understand and really start looking at – especially in these potentially vulnerable areas.”

Schroeder is also a faculty affiliate with the Institute for Human-Centered Artificial Intelligence (HAI) and a center fellow, by courtesy, at the Stanford Woods Institute for the Environment. Co-authors on the paper are from Georgia Institute of Technology, University of Tasmania, and Dartmouth College.

This research was supported by a National Science Foundation Graduate Research Fellowship, National Science Foundation Award No. 1745137, and the NASA Cryospheric Science Program.

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JOURNAL

Nature Communications

DOI

10.1038/s41467-022-32632-2 

ARTICLE TITLE

Ice mass loss sensitivity to the Antarctic ice sheet basal thermal state

ARTICLE PUBLICATION DATE

14-Sep-2022