Glacial Ice Cores Reveal 15,000 Year Old Microbes

 

Extensive glaciation at high altitudes in the Tibetan Plateau.
Source: Reurinkjan

Known as the world’s “Third Pole”, the Tibetan Plateau holds a vast amount of Earth’s ice. Over 46,000 glaciers blanket the arid, elevated landscape, which is part of the expansive Hindu Kush Himalaya (HKH) mountain range. These mountains and their icefields collectively hold the largest volume of snow and ice outside the Arctic and Antarctic. One might easily assume that the ice is sterile and void of life beyond its inert composition, considering the ancient and inaccessible depths it descends to. However, a new investigation of Tibetan glacial ice cores reveals quite the opposite: these immense glaciers in fact hold a rich chronological record of frozen, unique microbial life.

Zhi-Ping Zhong is a postdoctoral paleoclimatology researcher at Ohio State University’s Byrd Polar and Climate Research Center, and the lead author of a new publication in the journal Microbiome outlining his team’s investigation of nearly 15,000-year-old microbes in Tibetan ice. Their innovation is in their methodology — it is notoriously difficult to isolate and preserve ancient microbial DNA well enough to resolve individual genomes, while simultaneously avoiding contamination or degradation of the sample. In addition, glacier ice contains very low levels of biomass, making contamination by today’s microbes and viruses an even more imposing risk. Zhong and his team pioneered a new approach that accomplished this difficult task with remarkable precision, permitting them to see right down to the ancient genes.

“We developed clean methods to remove the contaminants on glacier ice core surfaces,” Zhong explained in an interview with GlacierHub. “This helps guarantee we obtain the ‘real’ microbes and viruses that were archived in glacier ice, not contaminants.” The team’s methods involved meticulous shaving and disinfection of the cores down to their innermost ice, isolating relatively uncontaminated material for analysis. They expanded upon previous work by first validating their methods on artificial cores they had laced with known bacteria, allowing them to measure what amount of the mock contaminants remained. With more concrete data on the efficacy of their approach, they proceeded to clean and process the actual cores.

The ice cores used in the investigation were drilled by Lonnie Thompson and colleagues in 2015 from the Guliya Ice Cap. Thompson, a renowned paleoclimatologist and professor at Ohio State University since 1991, began (alongside Ellen Mosley-Thompson) building the Byrd Polar and Climate Research Center’s ice core collection several decades ago. Zhong emphasises that glacier ice does not only archive past climates and chemical information about Earth’s atmosphere — it also archives entire microbial ecosystems, providing a preserved biological record going back untold thousands of years. 

The research team’s meticulous contamination prevention and reduction methods both outside and inside the lab revealed certain groups of bacteria commonly found in glacier ice such as Janthinobacterium, Polaromonas, and Sphingomonas. However, investigation of viral genetic material uncovered entire genetic sequences which were unique to the study, revealing 28 novel genera. This rate of 88 percent novel genera found in the glacier ice is much higher than those found by viral analyses of ocean environments (52 percent unique genera) and soils (61 percent unique genera). Such discoveries at exceptional levels of detail are integral to Zhong’s goals for the study. He explains that he hopes to understand the mutation rates of microbes over long periods of time by comparing the frozen genomes with those of more current bacteria and viruses. “These efforts will provide us the possibility of using a sort of molecular clock to help date the ice.”

The potential applications of Zhong. et al’s methods don’t end on this planet, either. Extremophilic life on Earth (including hardy ice-dwelling bacteria and other microbes) are frequently studied as potential models for extraterrestrial life on other planets and moons. Numerous bodies in our solar system harbor water ice, albeit in more extreme climatic conditions, leading to the astrobiological assumption that such ice may be sufficient to provide habitable conditions for life. Because the team’s protocol was developed for microbial and viral extraction from high-elevation, cold, and dry environments on Earth, Zhong noted how similar techniques “may one day be applied in the search for life in the Martian polar regions as well in other icy worlds in our solar system.” 

These techniques hold great promise for expanding our understanding of microbial history and evolution, but alongside this field’s emergence comes the existential threat of climate change. A quarter of the Third Pole has melted since 1970, and according to a 2019 IPCC report, two-thirds of its glaciers are predicted to disappear within the next 80 years. These catastrophic trends are global to varying degrees, and with the melt comes the Earth-wide loss of a biological history going back hundreds of thousands of years, unsalvageable as these records transition to meltwater. 

Aware of this threat, the Byrd Polar and Climate Research Center has collected and preserved more than 7,000 meters of ice core sections over its 40 years of glacier ice analysis across the globe. The frozen room at the Byrd Center is a time capsule preserving histories of the world that soon may not be accessible anywhere else. Both the archived ice cores and Zhong’s methods may serve as a foundation for the next generation of researchers, working in a world where the only views of once magnificent and biology-rich glaciers are in shelved cylinders of ice, each four inches across and about a yard long. Scientists have barely begun to read the vast genetic tome that is contained in Earth’s glaciers — these new methods of recovering frozen genomes and preserving threatened ice are now facing a fruitful, fateful race against time.

Source/Credit: Columbia University Climate School / by Daniel Burgess

en090121_01

Sandia uncovers hidden factors that affect solar farms during severe weather

Sandia National Laboratories researchers Thushara Gunda, front, and Nicole Jackson examine solar panels at Sandia’s Photovoltaic Systems Evaluation Laboratory as summer monsoon clouds roll by. Using machine learning and data from solar farms across the U.S., they uncovered the age of a solar farm, as well as the amount of cloud cover, have pronounced effects on farm performance during severe weather.
(Photo by Randy Montoya)

 Sandia National Laboratories researchers combined large sets of real-world solar data and advanced machine learning to study the impacts of severe weather on U.S. solar farms, and sort out what factors affect energy generation. Their results were published earlier this month in the scientific journal Applied Energy.

Hurricanes, blizzards, hailstorms and wildfires all pose risks to solar farms both directly in the form of costly damage and indirectly in the form of blocked sunlight and reduced electricity output. Two Sandia researchers scoured maintenance tickets from more than 800 solar farms in 24 states and combined that information with electricity generation data and weather records to assess the effects of severe weather on the facilities. By identifying the factors that contribute to low performance, they hope to increase the resiliency of solar farms to extreme weather.

“Trying to understand how future climate conditions could impact our national energy infrastructure, is exactly what we need to be doing if we want our renewable energy sector to be resilient under a changing climate,” said Thushara Gunda, the senior researcher on the project. “Right now, we’re focused on extreme weather events, but eventually we’ll extend into chronic exposure events like consistent extreme heat.”

Hurricanes and snow and storms, oh my!

The Sandia research team first used natural-language processing, a type of machine learning used by smart assistants, to analyze six years of solar maintenance records for key weather-related words. The analysis methods they used for this study has since been published and is freely available for other photovoltaic researchers and operators.

“Our first step was to look at the maintenance records to decide which weather events we should even look at,” said Gunda. “The photovoltaic community talks about hail a lot, but the data in the maintenance records tell a different story.”

While hailstorms tend to be very costly, they did not appear in solar farm maintenance records, likely because operators tend to document hail damage in the form of insurance claims, Gunda said. Instead, she found that hurricanes were mentioned in almost 15% of weather-related maintenance records, followed by the other weather terms, such as snow, storm, lightning and wind.

“Some hurricanes damage racking — the structure that holds up the panels — due to the high winds,” said Nicole Jackson, the lead author on the paper. “The other major issue we’ve seen from the maintenance records and talking with our industry partners is flooding blocking access to the site, which delays the process of turning the plant back on.”

Using machine learning to find the most important factors

Next, they combined more than two years of real-world electricity production data from more than 100 solar farms in 16 states with historical weather data to assess the effects of severe weather on solar farms. They used statistics to find that snowstorms had the highest effect on electricity production, followed by hurricanes and a general group of other storms.

Then they used a machine learning algorithm to uncover the hidden factors that contributed to low performance from these severe weather events.

“Statistics gives you part of the picture, but machine learning was really helpful in clarifying what are those most important variables,” said Jackson, who primarily conducted statistical analysis and the machine learning portion of the project. “Is it where the site is located? Is it how old the site is? Is it how many maintenance tickets were submitted on the day of the weather event? We ended up with a suite of variables and machine learning was used to home in on the most important ones.”

She found that across the board, older solar farms were affected the most by severe weather. One possibility for this is that solar farms that had been in operation for more than five years had more wear-and-tear from being exposed to the elements longer, Jackson said.

Gunda agreed, adding, “This work highlights the importance of ongoing maintenance and further research to ensure photovoltaic plants continue to operate as intended.”

For snowstorms, which unexpectedly were the type of storm with the highest effect on electricity production, the next most important variables were low sunlight levels at the location due to cloud cover and the amount of snow, followed by several geographical features of the farm.

For hurricanes — principally hurricanes Florence and Michael — the amount of rainfall and the timing of the nearest hurricane had the next highest effect on production after age. Surprisingly low wind speeds were significant. This is likely because when high wind speeds are predicted, solar farms are preemptively shut down so that the employees can evacuate leading to no production, Gunda said.

Expanding the approach to wildfires, the grid

As an impartial research institution in this space, Sandia was able to collaborate with multiple industry partners to make this work feasible. “We would not have been able to do this project without those partnerships,” Gunda said.

The research team is working to extend the project to study the effect of wildfires on solar farms. Since wildfires aren’t mentioned in maintenance logs, they were not able to study them for this paper. Operators don’t stop to write a maintenance report when their solar farm is being threatened by a wildfire, Gunda said. “This work highlights the reality of some of the data limitations we have to grapple with when studying extreme weather events.”

“The cool thing about this work is that we were able to develop a comprehensive approach of integrating and analyzing performance data, operations data and weather data,” Jackson said. “We’re extending the approach into wildfires to examine their performance impacts on solar energy generation in greater detail.”

The researchers are currently expanding this work to look at the effects of severe weather on the entire electrical grid, add in more production data, and answer even more questions to help the grid adapt to the changing climate and evolving technologies.

This research was supported by the Department of Energy’s Solar Energy Technologies Office and was conducted in partnership with the National Renewable Energy Laboratory.

Source/Credit: Sandia National Laboratories

tn083121_01

Sea levels to become much more common as Earth warms

 

Extreme sea levels along coastlines across the world will become
100 times more frequent by the end of the century.
Image: Pexels

Global warming will cause extreme sea levels to occur almost every year by the end of the century, impacting major coastlines worldwide, according to new research from an international team of scientists.

Published today in Nature Climate Change, the research predicts that because of rising temperatures, extreme sea levels along coastlines across the world will become 100 times more frequent by the end of the century in about half of the 7,283 locations studied.

Co-author of the study, University of Melbourne’s Dr Ebru Kirezci, an ocean engineering researcher said areas where frequency of extreme sea levels are expected to increase faster include the Southern Hemisphere and subtropic areas, the Mediterranean Sea and the Arabian Peninsula, the southern half of North America’s Pacific Coast, and areas including Hawaii, the Caribbean, the Philippines and Indonesia.

“What we can also infer from this study, is that most of the eastern, southern and southwestern coastlines of Australia will be the impacted with almost an annual frequency of these extreme sea levels by 2100,” Dr Kirezci said.

“This increased frequency of extreme sea levels will occur even with a global temperature increase of 1.5 degrees Celsius. And the changes are likely to come sooner than the end of the century, with many locations experiencing a 100-fold increase in extreme events even by 2070.”

Lead author of the study, climate scientist at the US Department of Energy’s Pacific Northwest National Laboratory, Dr Claudia Tebaldi said it was no surprise that sea level rise will be dramatic even at 1.5 degrees and will have substantial effects on extreme sea level frequencies and magnitude.

“This study gives a more complete picture around the globe. We were able to look at a wider range of warming levels in very fine spatial detail,” Dr Tebaldi said.

The researchers called for more detailed studies to understand how the changes will impact communities within different countries. They added that the physical changes that the study describes will have varying impacts at local scales, depending on several factors, including how vulnerable the site is to rising waters and how prepared a community is for change.

“Public policy makers should take note of these studies and work towards improving coastal protection and mitigation measures. Building dykes and sea walls, retreating from shorelines, and deploying early warning systems are some of the steps which can be taken to adapt to this change,” Dr Kirezci said.

The research was led by the US based Joint Global Change Research Institute in collaboration with researchers from the University of Melbourne, IHE Delft Institute for Water Education in the Netherlands, the European Joint Research Centre in Italy, Princeton University, the University of Illinois, Rutgers University and the University of Bologna.

The study was funded by the US Environmental Protection Agency and their Department of Energy’s Office of Science.

Source/Credit: University of Melbourne

en083121_01

Exposure to air pollution linked with increased mental health issues

 

Exposure to traffic-related air pollution is associated with increased mental health service-use among people recently diagnosed with psychotic and mood disorders such as schizophrenia and depression, a study on data from over 13,000 people has found.

Increased use of mental health services reflects mental illness severity, suggesting that initiatives to lessen air pollution could improve outcomes for those with these disorders and reduce costs of the healthcare needed to support them.

The research was published in the British Journal of Psychiatry and funded by the National Institute for Health Research (NIHR) Maudsley Biomedical Research Centre.

In 2019 119,000 people lived with illegal levels of polluted air in London. Previous research has found that adults exposed to high levels of traffic-related air pollution are more likely to experience common mental health disorders such as anxiety and mild depression but, until now, little was known about whether air pollution exposure contributes to the course and severity after the onset of more serious mental illness.

Researchers at King’s College London, University of Bristol and Imperial College London analyzed data from 13,887 people aged 15 years and over who had face-to-face contact with South London and Maudsley NHS Foundation Trust (SLaM) services between 2008 and 2012. Individuals were followed from the date of their first face-to-face contact for up to seven years.

Anonymized electronic mental health records were linked with quarterly average modelled concentrations of air pollutants (20x20 meter grid points) at the residential address of the participants. These included nitrogen dioxide and nitrogen oxides (NO2 and NOx) and fine and coarse particulate matter (PM2.5 and PM10).

The study found people exposed to higher residential levels of air pollutants used mental healthcare services more frequently in the months and years following their initial presentation to secondary mental healthcare services compared to those exposed to lower air pollution.

The researchers found that for every 3 micrograms per cubic meter increase in very small particulate matter (PM2.5) and 15 micrograms per cubic meter increase in nitrogen dioxide (NO2) over a one-year period there was an increased risk of having an inpatient stay of 11 per cent and 18 per cent. Results also showed increases in PM2.5 and NO2 were associated with a 7 per cent and 32 per cent increased risk of requiring community-based mental healthcare for the same period. These findings were also replicated over a seven-year period.

Dr Ioannis Bakolis, Senior Lecturer in Biostatistics and Epidemiology at the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) King’s College London and lead author of the study, said: ‘There is already evidence linking air pollution to the incidence of mental disorders, but our novel findings suggest that air pollution could also play a role in the severity of mental disorders for people with pre-existing mental health conditions.’

He continued: ‘Our research indicates that air pollution is a major risk factor for increased severity of mental disorders. It is also a risk factor that is easily modifiable which suggests more public health initiatives to reduce exposure such as low emission zones could improve mental health outcomes as well as reduce the high healthcare costs caused by long-term chronic mental illness.’

According to the researchers, if the UK urban population’s exposure to PM2.5 was reduced by just a few units to the World Health Organization's recommended annual limit (10 micrograms per cubic metre), this would reduce usage of mental health services by around two per cent, thereby saving tens of millions of pounds each year in associated healthcare costs.

Dr Joanne Newbury, Sir Henry Wellcome Research Fellow, Bristol Medical School (PHS), and the study’s first author, added: ‘We observed these findings for both mood disorders and psychotic disorders, as well as for both inpatient and community-based mental healthcare, and over seven years follow-up. This suggests that air pollution may contribute to a broad range of mental health problems, across a wide spectrum of clinical need, and over long periods of time.

‘We now plan to examine whether air pollution is associated with a broader range of mental health, neurodevelopmental, and educational outcomes, particularly among children, who might be especially vulnerable to air pollution.’

South London and Maudsley NHS Foundation Trust provides comprehensive secondary mental healthcare to approximately 1.36 million people within the London boroughs of Croydon, Lambeth, Lewisham and Southwark. These are inner-city areas with high-traffic flows and high average air pollution concentrations compared to other UK urban areas that reflect London’s diversity in terms of ethnicity and wealth.

The researchers controlled the analyses for a number of potential variables that could influence the association between air pollution and service-use association, such as deprivation, population density, age, season, marital status and ethnicity. However, they cautioned that the study does not prove cause and effect, and further research needs to demonstrate exactly how air pollution might increase severity of mental health problems.

Dr Adrian James, President of the Royal College of Psychiatrists, said: ‘The environmental and climate emergency is also a mental health emergency. Our health is fundamentally linked to the quality of our environment, whether that's about cleaner air, access to green spaces or protection from extreme weather.

‘If air pollution is exacerbating pre-existing serious mental illnesses, such as schizophrenia, bipolar disorder and major depression, then improving air quality could reduce the pressure on mental health services. As we look ahead to our post-pandemic future, it is vital that we find ways to build back greener and prevent poor health. This important research presents a clear example where these go hand-in-hand.’

The research was funded by the National Institute for Health Research (NIHR), the NIHR Maudsley Biomedical Research Centre, Wellcome, the Economic and Social Research Council, and the UK Medical Research Council.

Press Release
Source / Credit: University of Bristol

Climate change is accelerating, according to comprehensive study

 Climate change is happening and accelerating. Earth will continue to warm. And these changes are unequivocally caused by human activities. Those are among the conclusions of the report published by the International Panel on Climate Change (IPCC), with University of Hawaiʻi at Mānoa Assistant Professor of oceanography Malte Stuecker as a contributing author.

Ocean temperature (blue=cold, red=warm) simulated at ultra-high resolution. Photo credit: IBS/ICCP‘s Aleph

“The latest IPCC report shows clearly that if we do not drastically curb our emissions, we will head towards temperatures that Earth has not seen in millions of years,” Stuecker summarizes. “Moreover, we can now say with certainty that all of the global warming that occurred since the mid-19th century is due to human activity. While these are sobering facts, we should certainly not despair. In fact, if societies choose a pathway of large reductions in greenhouse gas emissions now, the report also shows that we will avoid the worst possible future outcomes and Earth will experience only moderate additional warming over this century that we can likely adapt to.”

In addition to global warming, regional climate in many parts of the world is impacted by the cycling between warm El Niño and cold La Niña conditions in the eastern Pacific Ocean—commonly referred to as the El Niño-Southern Oscillation (ENSO). ENSO—has persisted without major interruptions for thousands to millions of years. This may also change in a future warmer world, though the recent IPCC report highlights uncertainties in potential changes in ENSO.

Rainfall will be more extreme as the climate warms. (Photo credit: Max LaRochelle via Unsplash)

Two additional studies

Continuing the long tradition of contributing to developing theories and advancing climate models around ENSO, researchers from the UH Mānoa School of Ocean and Earth Science and Technology (SOEST) recently published two additional studies addressing the complexity of this most important climate phenomenon.

SOEST atmospheric scientists, Associate Professor Christina Karamperidou and Professor Fei-Fei Jin, and Stuecker co-authored a review paper published in Nature Reviews Earth & Environment wherein they synthesized recent advancements in research on ENSO.

There is an emerging consensus among simulations of future climate under strong greenhouse gas emissions with the most recent generation of climate models that the variability of future ENSO sea surface temperature may increase as the climate warms.

“There is however still much uncertainty on the degree to which ENSO may change and the time at which these potential changes will emerge from ENSO’s natural variability,” said Karamperidou. “This is partly due to incomplete understanding of the phenomenon, partly due to known limitations of models in representing and resolving relevant processes, and partly due to the inherent limitations on our understanding imposed by the short length of the instrumental record.”

Additionally, led by researchers at the IBS Center for Climate Physics in Korea, Stuecker co-authored another study published in Nature Climate Change that produced a series of global climate model simulations with unprecedented spatial resolution. Boosted by the power of one of South Korea’s fastest supercomputers (Aleph), the new ultra-high-resolution simulations realistically represented processes that are usually missing from other models, though they play fundamental roles in the generation and termination of El Niño and La Niña events.

“From this highest resolution future climate model simulation that has been done to date, we conclude that it’s possible that ENSO variability could collapse under strong greenhouse warming in the future,” said Stuecker.

Further investigation is needed

This apparent contradiction in findings raises many interesting questions and highlights the need for further investigation.

“Regardless of the details of how El Niño changes in the future, rainfall and drought will become more extreme in the future due to the fact that we will be living in a warmer world with a hydrological cycle on steroids,” said Stuecker.

“Despite the spread of model projections on how ENSO may change under strong anthropogenic forcing, both the IPCC report and the Nature Reviews article demonstrate that its impacts on rainfall are very likely to be enhanced which has significant implications across the globe and the Pacific, including Hawaiʻi,” said Karamperidou.

Source / Credit: University of Hawaiʻi

Antarctic Ocean Flows: an excerpt from Atlas of a Changing Earth

In this visualization of Antarctica, we cruise along the coastline of the Amundsen Sea from Cape Dart to the Pine Island Glacier. Initially we pass the massive Getz Ice Shelf on our right stretching over 300 miles (500 km) along the coast. As we approach the Smith Glacier and the Dotson Ice Shelf, the sea surface becomes transparent allowing us to see the ocean flows moving under the surface. These flows portray the direction, speed and temperature of the ocean circulation based on version 3 of the ECCO ocean circulation model. The flows are colored by temperature, spanning the range from 29.75 degrees Fahrenheit (-1.25 degrees Celsius) shown in blue to 34.25 degrees Fahrenheit (+1.25 degrees Celsius) shown in red. We see the ocean flows circulating around the Pine Island Bay and under the adjacent floating ice tongue of the Thwaites Glacier.  

As we approach the Pine Island Glacier, we dip below the surface of the bay and see the stratification of the temperature in the ocean flows, with the coldest water shown in blue near the surface and the warmer water shown in red at lower depths. We move forward under the floating ice of the Pine Island Glacier and see how the warmer ocean flows are circulating under the glacier's floating tongue, eroding the ice from beneath.  

The topography in this visualization has been exaggerated by 4x above sea level and 15x below sea level in order to more clearly observe the change in ocean temperature at various depths.

Credit / Source: NASA's Scientific Visualization Studio

Wildfire Smoke and Early Births

Wildfire smoke exposure during pregnancy increases preterm birth risk, Stanford study finds

Smoke from wildfires may have contributed to thousands of additional premature births in California between 2007 and 2012. The findings underscore the value of reducing the risk of big, extreme wildfires and suggest pregnant people should avoid very smoky air.

Exposure to wildfire smoke during pregnancy increases the risk that a baby will be born too early, a new Stanford University study suggests.

The study, published Aug. 14 in Environmental Research, finds there may have been as many as 7,000 extra preterm births in California attributable to wildfire smoke exposure between 2007 and 2012. These births occurred before 37 weeks of pregnancy when incomplete development heightens risk of various neurodevelopmental, gastrointestinal and respiratory complications, and even death.

Wildfire smoke contains high levels of the smallest and deadliest type of particle pollution, known as PM 2.5. These specks of toxic soot, or particulate matter, are so fine they can embed deep in the lungs and pass into the bloodstream, just like the oxygen molecules we need to survive.

The research comes as massive wildfires are again blazing through parched landscapes in the western U.S. – just a year after a historic wildfire season torched more than 4 million acres of California and produced some of the worst daily air pollution ever recorded in the state. During the 2020 fire season, more than half of the state’s population experienced a month of wildfire smoke levels in the range of unhealthy to hazardous.

This year could be worse, said Stanford environmental economist Marshall Burke, a co-author of the new study. And yet much remains unknown about the health impacts of these noxious plumes, which contribute a growing portion of fine particle pollution nationwide and have a different chemical makeup from other ambient sources of PM 2.5, such as agriculture, tailpipe emissions and industry.

One possible explanation for the link between wildfire smoke exposure and preterm birth, the authors say, is that the pollution may trigger an inflammatory response, which then sets delivery in motion. The increase in risk is relatively small in the context of all the factors that contribute to the birth of a healthy, full-term baby. “However, against a backdrop where we know so little about why some women deliver too soon, prematurely, and why others do not, finding clues like the one here helps us start piecing the bigger puzzle together,” said co-author Gary Shaw, DrPH, a professor of pediatrics and co-primary investigator of Stanford’s March of Dimes Prematurity Research Center.

Extreme wildfires

The new results show wildfire smoke may have contributed to more than 6 percent of preterm births in California in the worst smoke year of the study period, 2008, when a severe lightning storm, powerful winds, high temperatures and a parched landscape combined for a deadly and destructive fire season – one that has now been dwarfed by the record-setting infernos of 2020 and ongoing blazes like the Dixie fire in Northern California.

“In the future, we expect to see more frequent and intense exposure to wildfire smoke throughout the West due to a confluence of factors, including climate change, a century of fire suppression and construction of more homes along the fire-prone fringes of forests, scrublands and grasslands. As a result, the health burden from smoke exposure – including preterm births – is likely to increase,” said lead author Sam Heft-Neal, a research scholar at Stanford’s Center on Food Security and the Environment.

The research provides new evidence for the value of investing in prescribed burns, mechanical thinning, or other efforts to reduce the risk of extreme wildfires. Given that premature births cost the U.S. healthcare system an estimated $25 billion per year, even modest reductions in preterm birth risk could yield “enormous societal benefits,” said Burke, an associate professor of Earth system science at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth). “Our research highlights that reducing wildfire risk and the air pollution that accompanies it is one way of achieving these societal benefits.”

‘No safe level of exposure’

The researchers analyzed satellite data of smoke plumes from the National Oceanic and Atmospheric Administration (NOAA) to identify smoke days for each of 2,610 zip codes. They paired these data with estimates of ground-level PM 2.5 pollution, which were developed using a machine learning algorithm that incorporates data from air quality sensors, satellite observations and computer models of how chemicals move through Earth’s atmosphere. They pulled additional data from California birth records, excluding twins, triplets and higher multiples, which commonly arrive early.

After accounting for other factors known to influence preterm birth risk, such as temperature, baseline pollution exposure and the mother’s age, income, race or ethnic background, they looked at how patterns of preterm birth within each zip code changed when the number and intensity of smoke days rose above normal for that location.

They found every additional day of smoke exposure during pregnancy raised the risk of preterm birth, regardless of race, ethnicity or income. And a full week of exposure translated to a 3.4 percent greater risk relative to a mother exposed to no wildfire smoke. Exposure to intense smoke during the second trimester – between 14 and 26 weeks of pregnancy – had the strongest impact, especially when smoke contributed more than 5 additional micrograms per cubic meter to daily PM 2.5 concentrations. “If one can avoid smoke exposure by staying indoors or wearing an appropriate mask while outdoors, that would be good health practice for all,” Shaw said.

The findings build on an established link between particle pollution and adverse birth outcomes, including preterm birth, low birth weight and infant deaths. But the study is among the first to isolate the effect of wildfire smoke on early births and to tease out the importance of exposure timing.

“Our work, together with a number of other recent papers, clearly shows that there’s no safe level of exposure to particulate matter. Any exposure above zero can worsen health impacts,” said Burke, who is also deputy director of the Center on Food Security and the Environment and a senior fellow at Stanford’s Freeman Spogli Institute for International Studies. “While as a society it will be extremely difficult to fully eliminate all pollutants from the air, our research suggests that further reductions in key pollutants below current ‘acceptable’ levels could be massively beneficial for public health.”

This work was supported by the Robert Wood Johnson Foundation and the March of Dimes Prematurity Research Center at Stanford University School of Medicine.

Source / Credit: Stanford University

Blue-green algae key to unlocking secrets of ancient past

Oxygen-producing bacteria emerged a thousand millions years before the great oxygenation event approximately 2400 million years ago, scientists have found.

The blue green algae, which is responsible for seeping oxygen into the Earth’s atmosphere, changing the planet forever, diversified from its relatives to cope with the rise of the gas.

To understand how oxygen shaped early life, scientists at the University of Bristol have been investigating when cyanobacteria evolved and when they began using antioxidants called superoxide dismutase enzymes (SODs) to manage reactive oxygen.

They devised a ‘molecular clock’ using geochemical records, cyanobacteria fossils and genetic information to create a timeline of events.

Around 2500 million years ago, young Earth was unrecognizable. No ozone layer existed and there was no oxygen to breathe in the atmosphere. Instead, the planet was dominated by microbes. Cyanobacteria are the only bacteria capable of oxygenic photosynthesis, a process also used by plants to convert carbon dioxide into oxygen using sunlight. Today, cyanobacteria are widespread throughout the ocean, but then they were mostly restricted to freshwater and land.

Oxygen is highly reactive and toxic. Cyanobacteria uses SODs to protect against e these effects which all have different evolutionary origins - and use different trace metals. 

Group leader author of the paper Dr Patricia Sanchez-Baracaldo of Bristol’s School of Geographical Sciences said: “We studied the evolutionary history of four of these antioxidant enzymes: NiSOD, CuZnSOD and Fe- and Mn-utilising SODs. Such SODs are found in everything from animals to plants and bacteria, where they manage ROS by converting superoxide free radicals into hydrogen peroxide.

PhD student, Joanne Boden said: “We discovered that cyanobacteria had acquired their SOD genes from other bacteria on several occasions throughout history. As a result, different strains used different antioxidant enzymes depending on their circumstances. For example, cyanobacteria which live planktonic lifestyles, floating in the ocean, often use NiSOD. Whereas most cyanobacteria, regardless of their habitat, use Mn- or Fe-SODs.

“The evolutionary trajectory of a different SOD, using copper and zinc cofactors instead of nickel matched those of older, more ancestral cyanobacteria which diversified at least 2,700 million years ago. This suggests that oxygen-producing bacteria were equipped with mechanisms of managing ROS before the global atmosphere was flooded with oxygen.”

This genomic record, which has been published in Nature Communications, contains vital information about ancient habitats and proves the existence of life on land and in the ocean at that time.

Dr Sanchez-Baracaldo said: “Cyanobacteria worked out early in their evolution how to protect themselves against the side effects of oxygen.  

"Our analyses of metalloenzymes dealing with reactive oxygen species (ROS) show that marine geochemical records alone may not predict patterns of metal usage by living organisms found in other environments such as freshwater and terrestrial habitats.”

The team now plan to investigate when other antioxidants evolved.

Paper:

‘Cyanobacteria and biogeochemical cycles through Earth history’ in Nature Communications by J Boden, KO Konhauser, LJ Robbins, and P Sánchez-Baracaldo.

Source / Credit: University of Bristol