Friday, November 15, 2024

Political abuse on X is a global, widespread, and cross-partisan phenomenon, suggests new study




New study suggests that individuals on social media platform, ‘X’, who deviate from their party norms are quickly treated as if they were a political enemy.




City St George’s, University of London




new study suggests that political abuse is a key feature of political communication on social media platform, ‘X’, and whether on the political left or right, it is just as common to see politically engaged users abusing their political opponents, to a similar degree, and with little room for moderates.

While previous research into such online abuse has typically focused on the USA, the current study found that abuse followed a common ally-enemy structure across the nine countries for which there was available data: Canada, France, Germany, Italy, Poland, Spain, Turkey, UK, and the USA.

Led by City, St George’s, University of London, in collaboration with the Alan Turing Institute and others, the study suggests that individuals who deviate from their party norms are quickly treated as if they are a political enemy.

Such ‘outlier’ individuals highlighted by the study include US politicians Liz Cheney and Tulsi Gabbard.  

Cheney, a former Republican congresswoman in the US, broke ranks with her party, choosing to support the impeachment of Donald Trump for the January 6, 2021 storming of the US capitol.

Gabbard, originally a representative for the Democrats, defected to the Republicans very shortly after the current study completed.

Similarly, in the UK, the study found that former pro European Conservative party politicians such as Anna Soubry were endorsed by partisans (a person who strongly supports a political party) on the political left, and attacked by partisans on the political right.

In the study, the researchers used a complete data sample of X (then called Twitter) users posts, comprising 375 million tweets over a 24-hour period in September 2022. They mapped the posts of these users to another sample of over 1,800 politicians who have an active X account. 

By observing which users retweeted which politicians, the researchers were able to estimate what the political leaning of each user was, either to the left or right.

They also measured the toxicity of the content of political posts to measure political abuse on X.

The study found that posts which mentioned political opponents were consistently more toxic than mentions of political allies. While political interactions, in general, were more toxic than non-political interactions in all the countries with available data. 

While much attention has been given to social media facilitating the formation of ‘echo chambers,’ where individuals are only exposed to similar content, this study highlights the other side: X also enables communication across political groups, but the nature of this communication is often abusive.

The type of abuse aimed at political opponents which the study analysed is sometimes called ‘affective polarisation’, the phenomenon where partisans have negative feelings and emotions towards members of opposing political parties.

First author of the study, Dr Max Falkenberg, currently at the Department of Network & Data Science, Central European University, said:

“Many of these trends may have worsened: Since Elon Musk's takeover of Twitter, and the restrictions on data introduced, we no longer have access to the high quality data required to study these issues. This lack of transparency is democratically problematic and of significant concern if we are to improve the quality of political communication online.”

Andrea Baronchelli, Professor of Mathematics at City, St George’s, University of London, and who led the project, said:

“Our research reveals a key appeal of large platforms like X/Twitter: the chance to engage in aggressive exchanges with political opponents - unlike smaller platforms that simply allow conversations among like-minded users. This work confirms that the trend spans across countries, suggesting a society where the ‘other’ is viewed only as an opponent, and listening is reserved for allies. Recognising the implications for democratic life, our team will continue to study its broader impacts.”

Read the peer-reviewed article in the journal, Nature Communications.

ENDS


Notes to Editor

To speak to Dr Max Falkenberg (corresponding author) or Professor Andrea Baronchelli, contact Dr Shamim Quadir, Senior Communications Officer, School of Science & Technology, City St George’s, University of London. Tel: +44(0) 207 040 8782 Email: shamim.quadir@city.ac.uk.

 

To read a copy of the embargoed manuscript for the study article:

Patterns of partisan toxicity and engagement reveal the common structure of online political communication across countries 

please request it from Dr Shamim Quadir, Senior Communications Officer, School of Science & Technology, City St George’s, University of London

The article will go live at this URL once the embargo lifts: https://www.nature.com/articles/s41467-024-53868-0

 

About City St George’s, University of London

City St George’s, University of London is the University of business, practice and the professions.

City St George’s attracts around 27,000 students from more than 150 countries. 

Our academic range is broadly-based with world-leading strengths in business; law; health and medical sciences; mathematics; computer science; engineering; social sciences; and the arts including journalism, dance and music.

In August 2024, City, University of London merged with St George’s, University of London creating a powerful multi-faculty institution. The combined university is now one of the largest suppliers of the health workforce in the capital, as well as one of the largest higher education destinations for London students.  

City St George’s campuses are spread across London in Clerkenwell, Moorgate and Tooting, where we share a clinical environment with a major London teaching hospital.

Our students are at the heart of everything that we do, and we are committed to supporting them to go out and get good jobs.

Our research is impactful, engaged and at the frontier of practice. In the last REF (2021) 86 per cent of City research was rated as ‘world-leading’ 4* (40%) and ‘internationally excellent’ 3* (46%). St George’s was ranked joint 8th in the country for research impact with 100% of impact cases judged as ‘world-leading’ or ‘internationally excellent’. As City St George’s we will seize the opportunity to carry out interdisciplinary research which will have positive impact on the world around us.

Over 175,000 former students in over 170 countries are members of the City St George’s Alumni Network.

City St George’s is led by Professor Sir Anthony Finkelstein.

 

Increase in crisis coverage, but not the number of crisis news events



Researchers looked at nearly 240 years of crisis coverage in The Times to see how coverage has change over time


Norwegian University of Science and Technology




The world appears to be plagued by crises.

“The financial crisis, the European debt crisis, the migration crisis, the COVID-19 pandemic, the war in Ukraine, the war in Gaza… The world seems to be stumbling from one existential crisis to the next, barely recovering from one before the next one hits,” said Stefan Geiß, a professor from the Department of Sociology and Political Science at the Norwegian University of Science and Technology (NTNU).

However, are there really more crises now than before?

Has it always been this way, or is something new happening? And if there are more public crises today than in the past, what is causing them?

Geiß decided to investigate the matter together with two colleagues, PhD research fellow Conor A. Kelly from the same department and Christina Viehmann from GESIS in Cologne. Their results were recently published in the Journal of Communication.

Data from 1785 to the present day

“We investigated crisis coverage in The Times newspaper spanning 235 years, and found some interesting preliminary results.”

The researchers went all the way back to 1785 to analyze developments in coverage. The Times is a serious, rather conservative newspaper, and is certainly not known for sensationalism.

In order to analyze such vast volumes of information, significant computing power was absolutely essential.

“Our research harnesses the power of computerized text analysis, enabling us to look back in time and see how previous generations understood the crises they faced,” said Geiß.

The analysis focused on news articles in The Times. To check the validity of their analysis, they compared the results with data from The GuardianThe EconomistNeue Zürcher Zeitung, and The Washington Evening Star.

Identified more than 1000 crisis events

“We identified more than 1000 different crisis events that led to major news waves from 20 different types of crises. The most frequent were government crises, geopolitical crises, economic crises, epidemics and disasters,” said Geiß.

So, the fact that the media talk about crises is nothing new, and major news waves tend to occur on average around four times a year. However, while crises in the past were more spread out over time, they now tend to occur in clusters.

“We found that crisis events have become somewhat more frequent, but they tend to occur in more ‘clustered’ or ‘pulsating’ patterns rather than being evenly spread out over time,” said Geiß.

However, there is not necessarily a clear connection between the crises themselves and the crisis coverage.

“The increase in the use of crisis rhetoric is much stronger than the increase in the frequency of crises,” explained the professor.

In other words, crisis rhetoric is used much more frequently than before, but not all of it leads to noticeable news waves. Crisis rhetoric in individual articles does not necessarily create a sense of a public crisis or trigger a wave of news coverage regarding the situation everyone is concerned about.

There is, however, a period that appears quite atypical, as the two largest clusters of crisis waves ever recorded fall within this timeframe: the present.

“News coverage involving crisis rhetoric and the number of crisis events has been much greater in the last two decades than it was previously. The increase in crisis coverage is not just a British phenomenon either; it appears to be a trend in Western countries across various types of media.”

So why is this the case?

Several reasons for the increase in crisis coverage

According to the researchers, crisis rhetoric and to some extent what is portrayed as crisis events appear to be a response to three main factors:

1. Intensified crisis PR.

Interest groups pressure the media into perceiving something as a crisis. There are more of these groups, and they have become more professional. They also cover more different causes and sectors of society. It has therefore become easier for the media to experience, perceive and portray as a crisis events that would probably have been ignored or regarded as less serious in the past.

If something is perceived as a crisis, it increases the possibility that people with power and authority will allocate more money to the area; and the more power news media outlets get, the more relevant this becomes.

2. More diverse public spending across multiple sectors.

This is a complicated point. It concerns how public authorities are much more involved in more aspects of society than before, and how more of us are more concerned with what is happening around us.

For example, a larger proportion of the population is educated, and almost everyone has the right to vote. We therefore perceive it as more important to stay informed about what is happening in our local communities and around the world.

As more people wanted to know how their tax money was being spent and who to vote for, there was a greater interest in news coverage of politics. Mass media quickly gained a larger audience until the market became fully saturated in the 1950s. (See a detailed explanation of the contributing factors in the fact box.)

For politicians, being visible to a wider audience in the media has also become more important.

3. Increasing independence for news media outlets in relation to political parties.

In the past, media outlets were often tied to political parties and therefore not as dependent on making a profit.

An independent press has more power than before, but as competition increases and media outlets must generate a larger share of their revenue themselves, it may also be tempting to use crisis coverage to attract attention and income.

“These three factors are just the tip of the iceberg. The interplay among financial, political and communicative factors is extremely complex,” said Geiß.

However, it seems that the crisis events are less closely connected to crisis coverage than they were in the past. It is not necessarily the case that every event that receives crisis coverage is actually a crisis, and crisis rhetoric is not always effective. Most people do not always perceive events as a crisis, even if the media portrays them as such.

The internet, along with the fact that major media outlets now face both national and international competition to a much greater extent than before, may also be contributing to an increase in crisis coverage, although it is too early to say for sure.

Diverting attention away from other issues

Is it really that dangerous if the media exaggerate a bit from time to time?

“Crisis coverage keeps the public engaged while pushing many other pressing issues to the sidelines,” said Geiß.

The apparent crises divert attention away from issues that are not necessarily as newsworthy, but which may be equally important.

These pertain to worrying developments in society, such as the ever-widening gap between the rich and poor in many countries, or major humanitarian crises that have gradually developed over time.

Reference: Geiß S, Viehmann C, Kelly CA (2024). Inflation of crisis coverage? Tracking and explaining the changes in crisis labeling and crisis news wave salience 1785–2020. Journal of Communication, 2024, jqae033. https://doi.org/10.1093/joc/jqae033

https://academic.oup.com/joc/article/doi/10.1093/joc/jqae033/776040

 

White smokers on the lake floor



Spectacular chimneys discovered in the Dead Sea


Helmholtz Centre for Environmental Research - UFZ

HALITE CHIMNEYS 

video: 

HALITE CHIMNEYS / New type of submarine smokers in the Dead Sea

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Credit: UFZ




The Dead Sea is a highly dynamic system: Its level has been dropping by roughly one meter per year for more than 50 years, because it is cut off from key tributaries and is losing large quantities of water through evaporation as a result of drought and heat. The surface has thus dropped to roughly 438 meters below sea level. This decline in the lake, which borders Israel, Jordan and the West Bank under Palestinian administration, has significant consequences, especially for the groundwater. The groundwater level is falling, making it increasingly difficult for neighbouring countries to access groundwater resources. For many years, UFZ hydrogeologist Dr. Christian Siebert has been researching how the dynamics of the groundwater system in this region are changing and how aquifers are finding new paths in the rock strata both on land and below the Dead Sea. A team of divers he deployed has now discovered chimney-shaped vents on the lake floor that discharge a shimmering fluid. "These bear a striking similarity to black smokers in the deep sea, but the system is completely different," says the UFZ researcher. Scientists from the fields of mineralogy, geochemistry, geology, hydrology, remote sensing, microbiology and isotope chemistry from a total of ten research institutions were involved in investigating and analysing the phenomenon.

 

While black smokers along the mid-ocean ridge emit hot water containing sulphides at a depth of several thousand metres, the researchers in the Dead Sea discovered that highly saline groundwater flows out through the chimneys at the bottom of the lake. But where is the salt coming from? The explanation: The groundwater from the surrounding aquifers penetrates into the saline lake sediments, leaching out extremely old and thick layers of rock consisting mainly of the mineral halite. It then flows into the lake as brine. "Because the density of this brine is somewhat lower than that of the water in the Dead Sea, it rises upwards like a jet. It looks like smoke, but it's a saline fluid," explains Christian Siebert. Contact with the lake water causes the dissolved salts, especially the halite, to spontaneously crystallize after emerging from the lake bed, where it forms the vents observed for the first time in the world. These can grow by several centimetres within a single day. Many of the slender chimneys were one to two meters high, but they also include giants more than seven meters high, with a diameter of more than 2-3 meters. Minuscule traces of 36Cl, a radioisotope from space, and the genetic verification of freshwater microbes in the water from the chimneys have shown that the white smokers have their origin in the aquifers in the surrounding area. The salts were thus not absorbed until the last few meters before the water entered the Dead Sea.

 

These white smokers are especially important because they can serve as an early warning indicator for sinkholes. These are subsidence craters up to 100 meters wide and up to 20 meters deep, thousands of which have formed along the Dead Sea in recent decades. They are formed by karstification of the subsoil, i.e. by the dissolution of massive layers of salt. This forms giant cavities above which the ground can collapse at any time. "To date, no one can predict where the next sinkholes will occur. They are also life-threatening and pose a threat to agriculture and infrastructure," says Christian Siebert. The research team was able to show that the chimneys had formed wherever the land surface subsequently collapsed over a large area and the karstification process had apparently been especially efficient. "This makes the white smokers an outstanding forecasting tool for locating areas that are at risk of collapse in the near future," he says. Autonomous watercraft equipped with multibeam echosounders or side-scanning sonar systems could be used to map the chimneys to a high degree of precision. "This would be the only method to date, and a highly efficient one, for identifying regions at risk of imminent collapse."

An individual submarine chimney at a depth of roughly 30 m.

Sinkhole

  

 

European initiative to clear old munitions from the seas



Project launch of MMinE-SwEEPER at GEOMAR



Helmholtz Centre for Ocean Research Kiel (GEOMAR)





Whether it is the Baltic, the North Sea, the Mediterranean or the Black Sea, there is no European sea without a significant amount of old munitions. The remnants of war not only threaten fishing, shipping and other uses, but also pose a growing threat to marine ecosystems and human health. Over time, metal casings corrode, explosives lie exposed on the seabed and toxins leach into the environment. However, clearance is complex and can itself pose a potential risk to the marine environment.

MMinE-SWEEPER is the first major project to tackle this problem on a European scale. Under the leadership of Professor Dr Jens Greinert from the GEOMAR Helmholtz Centre for Ocean Research in Kiel, scientifically sound technical solutions for munitions clearance in European waters will be developed and tested. The EU is supporting the project with almost six million euros in funding.

“Removing munitions from our waters is not only a matter of safety, but also a responsibility towards future generations,” says Professor Dr Jens Greinert, marine geologist and munitions expert at GEOMAR. “With MMinE-SwEEPER, we want to come closer to a European solution, share knowledge, advance technologies and, most importantly, improve communication between EU countries on this sensitive security issue.”

On 13-14 November, the 20 international project partners are meeting in Kiel, Germany, for a kick-off meeting to initiate the first steps of this ambitious project. The aim is to develop a systematic approach to the detection, assessment and clearance of unexploded ordnance (UXO) in order to minimise risks to people and the environment, and to protect biodiversity and people. The results of MMinE-SwEEPER will not only provide a scientific basis for sustainable munitions clearance, but will also serve as a basis for EU-wide standards and guidelines.

Representatives from two Directorates-General of the European Commission are also involved: the Directorate-General for Maritime Affairs and Fisheries (DG MARE) and the Directorate-General for Migration and Home Affairs (DG HOME). Their role is to develop, implement and manage EU policies, legislation and funding programmes.

Professor Greinert: “I hope, and am very confident, that this project will finally lead to a truly European approach to this problem in time to mitigate the serious problems.”

 

Key Objectives of the MMinE-SwEEPER Project:

  • Pooling Knowledge and Management Approaches: The project consolidates existing knowledge and experience from different countries and international projects. Relevant stakeholders from authorities, business, and civil society will be involved to develop solutions for munitions clearance.
  • Promoting Technological Advances: A key focus is on the further development of robotics, 3D imaging, and AI-supported analysis tools for munitions detection and classification. Autonomous underwater vehicles (AUVs) equipped with intelligent algorithms will be developed to identify munitions objects.
  • Real-world Testing and Validation: New technologies and methods will be tested in artificial test areas and real dump sites across Europe.
  • Building Capacity and Strengthening Collaboration: The project will promote the exchange of knowledge between European countries and different stakeholders by organising training sessions, webinars, and workshops. The aim is to create a sustainable community of experts and to strengthen collaboration between the public and private sectors.
  • Strengthening European Cooperation: The project fosters cooperation within Europe by introducing new technologies for munitions clearance and advising policy-makers on developing solutions.

Funding:

The MMinE-SwEEPER project (Marine Munition in Europe - Solutions with Economic and Ecological Profits for Efficient Remediation) is funded by the EU under the Horizon Europe research funding programme (Cluster 3: Civil Security for Society) with almost six million euros until March 2028.

 

Humans, not AI, are always accountable for healthcare decisions, say experts at QF’s WISH 2024



A panel of bioethicists and legal experts discussed the ethical implications of AI in healthcare at the global conference in Doha



WISH/QF

AI in Healthcare panel at WISH 

image: 

Citation: (Left to Right); UK Health Minister Andrew Gwynne; Dr. Barry Solaiman, Assistant Professor of Law at HBKU; Dr Tamar Schiff, Post-Doctoral Fellow at the Division of Medical Ethics at NYU; Dr Hans Henri P. Kluge, WHO Regional Director, EURO; Dr. Mohammed Ghaly, Professor of Islam and Bioethics at the Centre for Islamic Legislation and Ethics at Qatar Foundation’s Hamad Bin Khalifa University; along with the moderator

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Credit: World Innovation Summit for Health




14 November 2024. Doha, Qatar — A panel of bioethicists, legal and policy experts at the World Innovation Summit for Health (WISH) discussed the use of Artificial Intelligence (AI) in healthcare, focussing on accountability and the importance of including diverse data sets.

The discussion on the ethics of AI in healthcare, held at the end of the summit’s first day, was based on the report ‘AI and Healthcare Ethics in the Gulf Region: An Islamic Perspective on Medical Accountability’. This session featured the report’s lead author Dr. Mohammed Ghaly, Professor of Islam and Bioethics at the Centre for Islamic Legislation and Ethics at Qatar Foundation’s Hamad Bin Khalifa University (HBKU).

Prof Ghaly said that accountability for the outcomes of decisions of AI-enabled medical technologies needs to lay squarely with people: “It doesn’t matter how smart the machine is, it cannot be responsible for any mistakes.” He added that responsibility will no longer lie with the physician alone. Instead, we need to also hold developers, programmers and data scientists to account for data bias. “We are moving into a world of collective liability,” Ghaly said.  

The panel highlighted several challenges to the ethical management of AI-enabled medical technologies. This issue of accountability is compounded by the complexity and opacity of AI algorithms, which can obscure the decision-making process and diffuse blame. Issues related to privacy and data protection, obtaining informed consent, addressing social disparities, considerations of medical consultation, and the aspects of empathy and sympathy pose additional challenges in the integration of AI.

The expert panel also included Dr. Barry Solaiman, Assistant Professor of Law at HBKU; Dr Hans Henri P. Kluge, WHO Regional Director, EURO; UK Health Minister Andrew Gwynne, Parliamentary Under Secretary of State for Public Health and Prevention; and Dr Tamar Schiff, Post-Doctoral Fellow at the Division of Medical Ethics at NYU.

The data used to train AI is central to understanding “what biases are baked into it,” said Dr. Schiff. In order to develop AI-enabled health systems that worked for everyone, the data needs to come from diverse data sets, the panel agreed.

While much of existing data sets currently being used to train AI in healthcare is based on data gathered in Western countries, “There are well resourced countries that can produce their own data and come to the table. We need entities from around the world to contribute,” said Dr. Ghaly.  

This year, WISH was opened in the presence of Her Highness Sheikha Moza bint Nasser, Chairperson of Qatar Foundation and founder of WISH. The opening ceremony, held at Qatar National Convention Centre in Doha, included speeches from Her Excellency Dr. Hanan Mohamed Al Kuwari, Qatar’s former Minister of Public Health; Lord Darzi of Denham, Executive Chair of WISH; and Christos Christou, President of Médecins Sans Frontières. 

The theme of WISH 2024 is ‘Humanizing Health: Conflict, Equity and Resilience’. It aims to highlight the need for innovation in health to support everyone, leaving nobody behind and building resilience, especially among vulnerable societies and in areas of armed conflict.

Ahead of the summit, WISH entered into a strategic partnership with the World Health Organization (WHO), collaborating on the development of a series of evidence-based reports and policy papers, as well as working with the United Nations’ health agency to develop a post-summit implementation strategy. 

The summit features more than 200 experts in health speaking about evidence-based ideas and practices in healthcare innovation to address the world’s most urgent global health challenges.


AI method can spot potential disease faster, better than humans




Washington State University

Testis tubule atrophy 

image: 

Traditionally, researchers and medical professionals identify pathology, or signs of disease, by analyzing and annotating tissues under a microscope like the image of testis (tubule atrophy) disease pictured here -- a process that can take many hours for one slide or image. The “deep learning” AI model developed at WSU was able to identify pathologies much faster than humans, sometimes catching signs that human pathologists had missed.

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Credit: Courtesy of Eric Nilsson, Skinner Laboratory, Washington State University




PULLMAN, Wash. – A “deep learning” artificial intelligence model developed at Washington State University can identify pathology, or signs of disease, in images of animal and human tissue much faster, and often more accurately, than people.

The development, detailed in Scientific Reports, could dramatically speed up the pace of disease-related research. It also holds potential for improved medical diagnosis, such as detecting cancer from a biopsy image in a matter of minutes, a process that typically takes a human pathologist several hours.

“This AI-based deep learning program was very, very accurate at looking at these tissues,” said Michael Skinner, a WSU biologist and co-corresponding author on the paper. “It could revolutionize this type of medicine for both animals and humans, essentially better facilitating these kinds of analysis.”

To develop the AI model, computer scientists Colin Greeley, a former WSU graduate student, and his advising professor Lawrence Holder trained it using images from past epigenetic studies conducted by Skinner’s laboratory. These studies involved molecular-level signs of disease in kidney, testes, ovarian and prostate tissues from rats and mice. The researchers then tested the AI with images from other studies, including studies identifying breast cancer and lymph node metastasis.

The researchers found that the new AI deep learning model not only correctly identified pathologies quickly but did so faster than previous models – and in some cases found instances that a trained human team had missed.

“I think we now have a way to identify disease and tissue that is faster and more accurate than humans,” said Holder, a co-corresponding author on the study.

Traditionally, this type of analysis required painstaking work by teams of specially trained people who examine and annotate tissue slides using a microscope—often checking each other’s work to reduce human error.

In Skinner’s research on epigenetics, which involves studying changes to molecular processes that influence gene behavior without changing the DNA itself, this analysis could take a year or even more for large studies. Now with the new AI deep learning model, they can get the same data within a couple weeks, Skinner said.

Deep learning is an AI method that attempts to mimic the human brain, a method that goes beyond traditional machine learning, Holder said. Instead, a deep learning model is structured with a network of neurons and synapses. If the model makes a mistake, it “learns” from it, using a process called backpropagation, making a bunch of changes throughout its network to fix the error, so it will not repeat it.

The research team designed the WSU deep learning model to handle extremely high-resolution, gigapixel images, meaning they contain billions of pixels. To deal with the large file sizes of these images, which can slow down even the best computer, the researchers designed the AI model to look at smaller, individual tiles but still place them in context of larger sections but in lower resolution, a process that acts sort of like zooming in and out on a microscope.

This deep learning model is already attracting other researchers, and Holder’s team is currently collaborating with WSU veterinary medicine researchers on diagnosing disease in deer and elk tissue samples.

The authors also point to the model’s potential for improving research and diagnosis in humans particularly for cancer and other gene-related diseases. As long as there is data, such as annotated images identifying cancer in tissues, researchers could train the AI model to do that work, Holder said.

“The network that we’ve designed is state-of-the-art,” Holder said. “We did comparisons to several other systems and other data sets for this paper, and it beat them all.”

This study received support from the John Templeton Foundation. Eric Nilsson, a WSU research assistant professor in the School of Biological Sciences, is also a co-author on this paper.

 

Living microbes discovered in Earth’s driest desert



American Society for Microbiology




Highlights:

  • The Atacama Desert is one of the most extreme habitats on Earth.
  • Atacama surface soil samples include a mix of DNA from inside and outside living cells.
  • A new technique allows researchers to separate external and internal DNA to identify microbes colonizing this hostile environment.
  • This approach for analyzing microbial communities could potentially be applied to other hostile environments, like those on other planets. 


Washington, D.C.—The Atacama Desert, which runs along the Pacific Coast in Chile, is the driest place on the planet and, largely because of that aridity, hostile to most living things. Not everything, though—studies of the sandy soil have turned up diverse microbial communities. Studying the function of microorganisms in such habitats is challenging, however, because it’s difficult to separate genetic material from the living part of the community from genetic material of the dead.

A new separation technique can help researchers focus on the living part of the community. This week in Applied and Environmental Microbiology, an international team of researchers describes a new way to separate extracellular (eDNA) from intracellular (iDNA) genetic material. The method provides better insights into microbial life in low-biomass environments, which was previously not possible with conventional DNA extraction methods, said Dirk Wagner, Ph.D., a geomicrobiologist at the GFZ German Research Centre for Geosciences in Potsdam, who led the study.

The microbiologists used the novel approach on Atacama soil samples collected from the desert along a west-to-east swath from the ocean’s edge to the foothills of the Andes mountains. Their analyses revealed a variety of living and possibly active microbes in the most arid areas. A better understanding of eDNA and iDNA, Wagner said, can help researchers probe all microbial processes. 

“Microbes are the pioneers colonizing this kind of environment and preparing the ground for the next succession of life,” Wagner said. These processes, he said, aren’t limited to the desert. “This could also apply to new terrain that forms after earthquakes or landslides where you have more or less the same situation, a mineral or rock-based substrate.” 

Most commercially available tools for extracting DNA from soils leave a mixture of living, dormant and dead cells from microorganisms, Wagner said. “If you extract all the DNA, you have DNA from living organisms and also DNA that can represent organisms that just died or that died a long time ago.” Metagenomic sequencing of that DNA can reveal specific microbes and microbial processes. However, it requires sufficient good-quality DNA, Wagner added, “which is often the bottleneck in low-biomass environments.” 

To remedy that problem, he and his collaborators developed a process for filtering intact cells out of a mixture, leaving behind eDNA genetic fragments left from dead cells in the sediment. It involves multiple cycles of gentle rinsing, he said. In lab tests they found that after 4 repetitions, nearly all the DNA in a sample had been divided into the 2 groups. 

When they tested soil from the Atacama Desert, they found Actinobacteria and Proteobacteria in all samples in both eDNA and iDNA groups. That’s not surprising, Wagner said, because the living cells constantly replenish the store of iDNA as they die and degrade. “If a community is really active, then a constant turnover is taking place, and that means the 2 pools should be more similar to each other,” he said. In samples collected from depths of less than 5 centimeters, they found that Chloroflexota bacteria dominated in the iDNA group. 

In future work, Wagner said he plans to conduct metagenomic sequencing on the iDNA samples to better understand the microbes at work, and to apply the same approach to samples from other hostile environments. By studying iDNA, he said, “you can get deeper insights into the real active part of the community.”
 

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The American Society for Microbiology is one of the largest professional societies dedicated to the life sciences and is composed of over 32,000 scientists and health practitioners. ASM's mission is to promote and advance the microbial sciences.

ASM advances the microbial sciences through conferences, publications, certifications, educational opportunities and advocacy efforts. It enhances laboratory capacity around the globe through training and resources. It provides a network for scientists in academia, industry and clinical settings. Additionally, ASM promotes a deeper understanding of the microbial sciences to diverse audiences.