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Thursday, January 05, 2023

Climate warming reduces organic carbon burial beneath oceans

Painstaking study of 50-plus years of seafloor sediment cores has surprise payoff

RICE UNIVERSITY

JOIDES Resolution — IMAGE: THE JOIDES RESOLUTION IS A SCIENTIFIC RESEARCH VESSEL OPERATED BY TEXAS A&M UNIVERSITY FOR THE INTERNATIONAL OCEAN DISCOVERY PROGRAM THAT DRILLS INTO THE OCEAN FLOOR TO COLLECT AND STUDY CORE SAMPLES. view more
CREDIT: COURTESY OF THE INTERNATIONAL OCEAN DISCOVERY PROGRAM

HOUSTON – (Jan. 4, 2023) – An international team of scientists painstakingly gathered data from more than 50 years of seagoing scientific drilling missions to conduct a first-of-its-kind study of organic carbon that falls to the bottom of the ocean and gets drawn deep inside the planet.

Their study, published this week in Nature, suggests climate warming could reduce organic carbon burial and increase the amount of carbon that’s returned to the atmosphere, because warmer ocean temperatures could increase the metabolic rates of bacteria.

Researchers from Rice University, Texas A&M University, the University of Leeds and the University of Bremen analyzed data from drilled cores of muddy seafloor sediments that were gathered during 81 of the more than 1,500 shipboard expeditions mounted by the International Ocean Discovery Program (IODP) and its predecessors. Their study provides the most detailed accounting to date of organic carbon burial over the past 30 million years, and it suggests scientists have much to learn about the dynamics of Earth’s long-term carbon cycle.

“What we’re finding is that burial of organic carbon is very active,” said study co-author Mark Torres of Rice. “It changes a lot, and it responds to the Earth's climatic system much more than scientists previously thought.”

The paper’s corresponding author, Texas A&M oceanographer Yige Zhang, said, “If our new records turn out to be right, then they’re going to change a lot of our understanding about the organic carbon cycle. As we warm up the ocean, it will make it harder for organic carbon to find its way to be buried in the marine sediment system.”

Carbon is the main component of life, and carbon constantly cycles between Earth’s atmosphere and biosphere as plants and animals grow and decompose. Carbon can also cycle through the Earth on a journey that takes millions of years. It begins at tectonic subduction zones where the relatively thin tectonic plates atop oceans are dragged down below thicker plates that sit atop continents. Downward diving oceanic crust heats up as it sinks, and most of its carbon returns to the atmosphere as carbon dioxide (CO2) from volcanoes.

Scientists have long studied the amount of carbon that gets buried in ocean sediments. Drilled cores from the ocean floor contain layers of sediments laid down over tens of millions of years. Using radiometric dating and other methods, researchers can determine when specific sediments were laid down. Scientists can also learn a lot about past conditions on Earth by studying minerals and microscopic skeletons of organisms trapped in sediments.

“There are two isotopes of carbon — carbon-12 and carbon-13,” said Torres, an assistant professor in Rice’s Department of Earth, Environmental and Planetary Sciences. “The difference is just one neutron. So carbon-13 is just a bit heavier.

“But life is lazy, and if something’s heavier — even that tiny bit — it’s harder to move,” Torres said. “So life prefers the lighter isotope, carbon-12. And if you grow a plant and give it CO2, it will actually preferentially take up the lighter isotope. That means the ratio of carbon-13 to -12 in the plant is going to be lower — contain less 13 — than in the CO2 you fed the plant.”

For decades scientists have used isotopic ratios to study the relative amounts of inorganic and organic carbon that was undergoing burial at specific points in Earth’s history. Based on those studies and computational models, Torres said scientists have largely believed the amount of carbon undergoing burial had changed very little over the past 30 million years.

Zhang said, “We had this idea of using the actual data and calculating their organic carbon burial rates to come up with the global carbon burial. We wanted to see if this ‘bottom-up’ method agreed with the traditional method of isotopic calculations, which is more ‘top down.’”

The job of compiling data from IODP expeditions fell to study first author, Ziye Li of Bremen, who was then a visiting student in Zhang’s lab at A&M.

Zhang said the study findings were shocking.

“Our new results are very different — they’re the opposite of what the isotope calculations are suggesting,” he said.

Zhang said this is particularly the case during a period called the mid-Miocene, about 15 million years ago. Conventional scientific wisdom held that a large amount of organic carbon was buried around this interval, exemplified by the organic-rich “Monterey Formation” in California. The team’s findings suggest instead that the smallest amount of organic carbon was buried during this interval over the last 23 million years or so.

He described the team’s paper as the beginning of a potentially impactful new way to analyze data that may aid in understanding and addressing climate change.

“It’s people’s curiosity, but I also want to make it more informative about what’s going to happen in the future,” Zhang said. “We’re doing several things quite creatively to really use paleo data to inform us about the present and future.”

The research was supported by the American Chemical Society’s Petroleum Research Fund (59797-DNI2). On behalf of the National Science Foundation, Texas A&M has served as the science operator of the IODP drill ship JOIDES Resolution for the past 36 years as part of the largest federal research grant currently managed by the university.

-30-

A schematic depiction of the burial and deep subduction of organic carbon.

CREDIT

R. Dasgupta/Rice University

Peer-reviewed paper:

“Neogene burial of organic carbon in the global ocean” | Nature | DOI: 10.1038/s41586-022-05413-6

Ziye Li, Yi Ge Zhang, Mark Torres and Benjamin J. W. Mills

https://www.nature.com/articles/s41586-022-05413-6

High-resolution IMAGES are available for download at:

https://news-network.rice.edu/news/files/2023/01/0104_CARBON-jr-lg.jpg
CAPTION: The JOIDES Resolution is a scientific research vessel operated by Texas A&M University for the International Ocean Discovery Program that drills into the ocean floor to collect and study core samples. (Photo courtesy of the International Ocean Discovery Program)

https://news-network.rice.edu/news/files/2023/01/0104_CARBON-mt-lg.jpg
CAPTION: Mark Torres (Photo by Tommy LaVergne/Rice University)

https://news-network.rice.edu/news/files/2023/01/0104_CARBON-RDfig-lg.jpg
CAPTION: A schematic depiction of the burial and deep subduction of organic carbon. (Image courtesy of R. Dasgupta/Rice University)

JOURNAL

Nature

DOI

10.1038/s41586-022-05413-6

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Neogene burial of organic carbon in the global ocean

ARTICLE PUBLICATION DATE

4-Jan-2023

Climate change could cause “disaster” in the world’s oceans, say UC Irvine scientists

Deep overturning circulation collapses with strong warming

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - IRVINE

Irvine, Calif., Jan. 4, 2023 — Climate-driven heating of seawater is causing a slowdown of deep circulation patterns in the Atlantic and Southern oceans, according to University of California, Irvine Earth system scientists, and if this process continues, the ocean’s ability to remove carbon dioxide from the atmosphere will be severely limited, further exacerbating global warming.

In a recent study published in Nature Climate Change, these researchers analyzed projections from three dozen climate models and found that the Atlantic Meridional Overturning Circulation and the Southern Meridional Overturning Circulation will slow by as much as 42 percent by 2100. The simulations suggest that under worst-case warming, the SMOC could cease entirely by 2300.

"Analysis of the projections from 36 Earth system models over a range of climate scenarios shows that unchecked global warming could lead to a shutdown of the ocean deep circulation,” said co-author J. Keith Moore, UCI professor of Earth system science. “This would be a climate disaster similar in magnitude to complete melting of the ice sheets on land.”

The importance of overturning circulation

In the Atlantic, as warm water flows northwards on the surface, it cools and evaporates, making it saltier and denser. This heavier water sinks into the deep ocean and proceeds to the south where it eventually rises back up, carrying from the depths the nutrients that are the food foundation of marine ecosystems.

In addition, globe-spanning ocean circulation creates a powerful factory for the processing of atmospheric carbon dioxide. The basic physical and chemical interaction of seawater and air – what Moore and his colleagues call a “solubility pump” – draws CO2 into the ocean. While the ocean circulation sends some carbon back to the sky, the net amount is sequestered in the ocean’s depths.

Additionally, a “biological pump” occurs as phytoplankton use CO2 during photosynthesis and in forming carbonate shells. When the plankton and larger animals die, they sink, slowly decomposing and releasing the carbon and nutrients at depth. Some comes back up with circulation and upwelling, but a portion remains banked beneath the waves.

“A disruption in circulation would reduce ocean uptake of carbon dioxide from the atmosphere, intensifying and extending the hot climate conditions,” Moore said. “Over time the nutrients that support marine ecosystems would increasingly become trapped in the deep ocean, leading to declining global-ocean biological productivity.”

Humans depend on the solubility pump and the biological pump to help remove some of the CO2 emitting into the air through fossil fuel burning, land use practices and other activities, according to Moore.

“Our analysis also shows that reducing greenhouse gas emissions now can prevent this complete shutdown of the deep circulation in the future,” he said.

Joining Moore on this project, which was funded by the U.S. Department of Energy, were lead author Yi Liu, UCI Ph.D. student in Earth system science; Francois Primeau, professor and chair of UCI’s Department of Earth System Science; and Wei-Lei Wang, professor of ocean and Earth sciences at Xiamen University in China. The study depended substantially on simulations developed by the Coupled Model Intercomparison Project phase 6 (CMIP6) project used to inform the IPCC climate assessments.

About the University of California, Irvine: Founded in 1965, UCI is a member of the prestigious Association of American Universities and is ranked among the nation’s top 10 public universities by U.S. News & World Report. The campus has produced five Nobel laureates and is known for its academic achievement, premier research, innovation and anteater mascot. Led by Chancellor Howard Gillman, UCI has more than 36,000 students and offers 224 degree programs. It’s located in one of the world’s safest and most economically vibrant communities and is Orange County’s second-largest employer, contributing $7 billion annually to the local economy and $8 billion statewide. For more on UCI, visit www.uci.edu.

Media access: Radio programs/stations may, for a fee, use an on-campus ISDN line to interview UCI faculty and experts, subject to availability and university approval. For more UCI news, visit news.uci.edu. Additional resources for journalists may be found at communications.uci.edu/for-journalists.

JOURNAL

Nature Climate Change

DOI

10.1038/s41558-022-01555-7

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Reduced CO2 uptake and growing nutrient sequestration from slowing overturning circulation

Cyclone researchers: Warming climate means more and stronger Atlantic tropical storms

Peer-Reviewed Publication

IOWA STATE UNIVERSITY

Cyclone studies — IMAGE: IOWA STATE UNIVERSITY'S CHRISTINA PATRICOLA AND COLLABORATORS HAVE RECENTLY PUBLISHED STUDIES OF TROPICAL CYCLONES AND THE HURRICANES THEY CAN PRODUCE. view more
CREDIT: PHOTO BY CHRISTOPHER GANNON/IOWA STATE UNIVERSITY.

AMES, Iowa – A warming climate will increase the number of tropical cyclones and their intensity in the North Atlantic, potentially creating more and stronger hurricanes, according to simulations using a high-resolution, global climate model.

“Unfortunately, it’s not great news for people living in coastal regions,” said Christina Patricola, an Iowa State University assistant professor of geological and atmospheric sciences, an affiliate of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory in California and a study leader. “Atlantic hurricane seasons will become even more active in the future, and hurricanes will be even more intense.”

The research team ran climate simulations using the Department of Energy’s Energy Exascale Earth System Model and found that tropical cyclone frequency could increase 66% during active North Atlantic hurricane seasons by the end of this century. (Those seasons are typically characterized by La Niña conditions – unusually cool surface water in the eastern tropical Pacific Ocean – and the positive phase of the Atlantic Meridional Mode – warmer surface temperatures in the northern tropical Atlantic Ocean).

The projected numbers of tropical cyclones could increase by 34% during inactive North Atlantic hurricane seasons. (Inactive seasons generally occur during El Niño conditions with warmer surface temperatures in the eastern tropical Pacific Ocean and the negative phase of the Atlantic Meridional Mode with cooler surface temperatures in the northern tropical Atlantic Ocean.)

In addition, the simulations project an increase in storm intensity during the active and inactive storm seasons.

The scientific journal Geophysical Research Letters recently published the findings. Ana C.T. Sena, an Iowa State postdoctoral research associate, is first author. (See sidebar.)

“Altogether, the co-occurring increase in (tropical cyclone) number and strength may lead to increased risk to the continental North Atlantic in the future climate,” the researchers wrote.

Patricola added: “Anything that can be done to curb greenhouse gas emissions could be helpful to reduce this risk.”

Cyclone studies in Cyclone Country

Iowa State is home to the Cyclones and storm sirens are part of the hype at most athletic contests. Talk of the Cyclones is all over campus. But North Atlantic tropical cyclones? What are they?

“Tropical cyclone is a more generic term than hurricane,” Patricola said. “Hurricanes are relatively strong tropical cyclones.”

Exactly, says the National Oceanic and Atmospheric Administration. Tropical cyclone is a general reference to a low-pressure system that forms over tropical waters with thunderstorms near the center of its closed, cyclonic winds. When those rotating winds exceed 39 mph, the system becomes a named tropical storm. At 74-plus mph, it becomes a hurricane in the Atlantic and East Pacific oceans, a typhoon in the northern West Pacific.

Patricola grew up in the Northeast and can still tell stories about 1991’s Hurricane Bob.

“That was a big one for us in Massachusetts,” she said. “For me, it was very exciting. It really caught my interest.”

She was a Weather Channel fanatic through a lot of hurricanes in the mid-1990s. And that led to studies of geological and atmospheric sciences at Cornell University in New York, followed by atmospheric science and climate research at Texas A&M University and Lawrence Berkeley National Laboratory. Patricola joined the Iowa State faculty in August 2020.

Patricola’s research interests include climate dynamics, climate variability and change, extreme weather events, atmosphere-ocean interactions, high-resolution climate modeling, land-atmosphere interactions, paleoclimates. And, tropical cyclones.

Why are tropical cyclone numbers so consistent?

Patricola and another set of collaborators have just published a second research paper about tropical cyclones. This one is also in Geophysical Research Letters, with Derrick Danso, an Iowa State postdoctoral research associate, as first author. The paper examines a possible explanation for the relatively constant number of tropical cyclones observed globally from year to year. (See sidebar.)

Could it be that African Easterly Waves, low pressure systems over the Sahel region of North Africa that take moist tropical winds and raise them up into thunderclouds, are a key to that steady production of storms?

Using regional model simulations, the researchers were able to filter out the African Easterly Waves and see what happened. As it turned out, the simulations didn’t change the seasonal number of Atlantic tropical cyclones. But, tropical cyclones were stronger, peak formation of the storms shifted from September to August, and the formation region shifted from the coast of North Africa to the Gulf of Mexico.

So African Easterly Waves many not help researchers predict the number of Atlantic tropical cyclones every year, but they do appear to impact important storm characteristics, including intensity and possibly where they make landfall.

Both papers call for more study.

“We are,” Patricola said, “chipping away at the problem of predicting the number of tropical cyclones.”

– 30 –

Read the papers

“Future Changes in Active and Inactive Atlantic Hurricane Seasons in the Energy Exascale Earth System Model,” Geophysical Research Letters, Volume 49, Issue 21, November 2022

Ana C.T. Sena, Iowa State University postdoctoral research associate in geological and atmospheric sciences
Christina Patricola, Iowa State assistant professor of geological and atmospheric sciences; U.S. Department of Energy’s Lawrence Berkeley National Laboratory affiliate
Burlen Loring, Lawrence Berkeley National Laboratory computer systems engineer

“Influence of African Easterly Wave Suppression on Atlantic Tropical Cyclone Activity in a Convection-Permitting Model,” Geophysical Research Letters, Volume 49, Issue 22, November 2022

Derrick Danso, Iowa State postdoctoral research associate in geological and atmospheric sciences

Christina Patricola, Iowa State assistant professor of geological and atmospheric sciences; Lawrence Berkeley National Laboratory affiliate

Emily Bercos-Hickey, Lawrence Berkeley National Laboratory postdoctoral research fellow

An Early Career Research Program grant to Patricola from the U.S. Department of Energy’s Office of Science, Office of Biological and Environmental Research, and Earth and Environmental Systems Modeling Program provided support for both studies.

JOURNAL

Geophysical Research Letters

DOI

10.1029/2022GL100267

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Future Changes in Active and Inactive Atlantic Hurricane Seasons in the Energy Exascale Earth System Model

Illinois Tech assistant professor awarded funding to stop spread of ‘forever chemicals’ into waterways

David Lampert’s project aimed at finding solutions to halting movement of PFAS in water resources receives phase II funding in EPA competition

Grant and Award Announcement

ILLINOIS INSTITUTE OF TECHNOLOGY

CHICAGO—January 4, 2023—Illinois Institute of Technology (Illinois Tech) Assistant Professor David Lampert was recently awarded funding by the U.S. Environmental Protection Agency’s People, Prosperity, and the Planet (P3) Student Design Competition for a project to stop the spread of “forever chemicals” into waterways. Lampert’s project—one of just three nationwide selected for phase II funding—focuses on preventing the movement of perfluoroalkyl and polyfluoroalkyl substances (PFAS) and is aimed at finding solutions that can be implemented on a large scale.

PFAS are a class of chemicals that have been used in a wide range of commercial products, including non-stick pans and shampoo, since the 1960s. Some types of PFAS have been linked to negative health impacts, including cancer, and are referred to as “forever chemicals” because they do not break down in nature. The use of some types of PFAS have decreased, but many still show up in products.

“If you take a blood sample of basically anyone and measure it, you can find a detectable level of these PFAS compounds,” said Lampert.

Lampert is leading a team of students in a project that will test various materials for their ability to capture PFAS as it moves. The team will also include students with business, social science, and entrepreneurial expertise as the project progresses.

Phase I funding from the EPA’s P3 project allowed Lampert and his team to conduct a pilot study, which involved designing a laboratory experiment to track the movement of PFAS through soil and groundwater over time and examine the ability of various materials to contain the pollution and protect surface water resources.

For phase II, Lampert plans to add water columns and worms to the soil system to see how water flow and animal burrowing impact the movement of PFAS. He will also test the soil for additional types of PFAS and study how worms bioaccumulate the compounds, which is important for understanding how PFAS spread to humans through bioaccumulation in fish. These findings will help Lampert identify and test potential intervention strategies for stopping the movement of PFAS.

“There’s a complicated hydrological-environmental modeling question there to try to understand this whole process of how the PFAS gets from a contaminated area to the receptors and people who might be exposed to it,” said Lampert. “Our goal is to find a solution that can be implemented on larger scales.”

Lampert’s team also plans to conduct a field test at an existing PFAS-heavy site. The ultimate goal of the project is to develop and demonstrate effective methods for preventing the movement of PFAS into water resources, improving water quality and protecting human health.

“I’m trying to understand what processes are happening in our water systems and trying to figure out how we can do better from an ecology point of view, a human health point of view, and sustainability point of view,” Lampert said.

Disclaimer: This content was developed under Assistance Agreement No. SU840180 and SV840421 awarded by the U.S. Environmental Protection Agency to David Lampert. It has not been formally reviewed by EPA. The views expressed in this document are solely those of the authors and do not necessarily reflect those of the Agency. EPA does not endorse any products or commercial services mentioned in this publication.

David Lampert, “Sorbent-Amended Caps for PFAS-Contaminated Sediments,” Environmental Protection Agency; Awards Number SU840180 and SV84042

Antibiotic residues in water a threat to human health

Peer-Reviewed Publication

KAROLINSKA INSTITUTET

Antibiotic residues in wastewater and wastewater treatment plants in the regions around China and India risk contributing to antibiotic resistance, and the drinking water may pose a threat to human health, according to a comprehensive analysis from Karolinska Institutet published in The Lancet Planetary Health. The researchers also determined the relative contribution of various sources of antibiotic contamination in waterways, such as hospitals, municipals, livestock, and pharmaceutical manufacturing.

”Our results can help decision-makers to target risk reduction measures against environmental residues of priority antibiotics and in high-risk sites, to protect human health and the environment,” says Nada Hanna, researcher at the Department of Global Public Health at Karolinska Institutet in Sweden, and the study’s first author. “Allocating these resources efficiently is especially vital for resource-poor countries that produce large amounts of antibiotics.”

Bacteria that become resistant to antibiotics are a global threat that can lead to untreatable bacterial infections in animals and humans.

Antibiotics can enter the environment during their production, consumption and disposal. Antibiotic residues in the environment, such as in wastewater and drinking water, can contribute to the emergence and spread of resistance.

Among the largest producers of antibiotics

The researchers have examined the levels of antibiotic residues that are likely to contribute to antibiotic resistance from different aquatic sources in the Western Pacific Region (WPR) and the South-East Asia Region (SEAR), regions as defined by the World Health Organization. These regions include China and India, which are among the world’s largest producers and consumers of antibiotics.

This was done by a systematic review of the literature published between 2006 and 2019, including 218 relevant reports from the WPR and 22 from the SEAR. The researchers also used a method called Probabilistic Environmental Hazard Assessment to determine where the concentration of antibiotics is high enough to likely contribute to antibiotic resistance.

Ninety-two antibiotics were detected in the WPR, and forty five in the SEAR. Antibiotic concentrations exceeding the level considered safe for resistance development (Predicted No Effect Concentrations, PNECs) were observed in wastewater, influents and effluents of wastewater treatment plants and in receiving aquatic environments. The highest risk was observed in wastewater and influent of wastewater treatment plants. The relative impact of various contributors, such as hospital, municipal, livestock, and pharmaceutical manufacturing was also determined.

Potential threat to human health

In receiving aquatic environments, the highest likelihood of levels exceeding the threshold considered safe for resistance development was observed for the antibiotic ciprofloxacin in drinking water in China and the WPR.

”Antibiotic residues in wastewater and wastewater treatment plants may serve as hot spots for the development of antibiotic resistance in these regions and pose a potential threat to human health through exposure to different sources of water, including drinking water,” says Nada Hanna.

Limitations to be considered when interpreting the results are the lack of data on the environmental occurrence of antibiotics from many of the countries in the regions and the fact that only studies written in English were included.

The research has been funded by the Swedish Research Council. The researchers declare no competing interests.

Publication: ”Antibiotic concentrations and antibiotic resistance in aquatic environments of the Western Pacific and South-East Asia Regions: a systematic review and probabilistic environmental hazard assessment”, Nada Hanna, Ashok J. Tamhankar and Cecilia Stålsby Lundborg. The Lancet Planetary Health, online January 4, 2023.

JOURNAL

The Lancet Planetary Health

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

”Antibiotic concentrations and antibiotic resistance in aquatic environments of the Western Pacific and South-East Asia Regions: a systematic review and probabilistic environmental hazard assessment”

ARTICLE PUBLICATION DATE

4-Jan-2023

NIH study links specific outdoor air pollutants to asthma attacks in urban children

Researchers focused on asthma attacks not caused by respiratory viruses

Peer-Reviewed Publication

NIH/NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES

Air emissions — IMAGE: AIR EMISSIONS AT A MANUFACTURING COMPLEX IN TORONTO, CANADA. view more
CREDIT: UN PHOTO/KIBAE PARK

Moderate levels of two outdoor air pollutants, ozone and fine particulate matter, are associated with non-viral asthma attacks in children and adolescents who live in low-income urban areas, a study funded by the National Institutes of Health has found. The study also identifies associations between exposure to the two pollutants and molecular changes in the children’s airways during non-viral asthma attacks, suggesting potential mechanisms for those attacks. The observational study is one of the first to link elevated levels of specific outdoor air pollutants in particular urban locations to distinct changes in the airways during asthma attacks not triggered by respiratory viruses, according to the investigators. The findings were published today in the journal The Lancet Planetary Health.

“The strong association this study demonstrates between specific air pollutants among children in impoverished urban communities and non-viral asthma attacks further augments the evidence that reducing air pollution would improve human health,” said Hugh Auchincloss, M.D., acting director of the National Institute of Allergy and Infectious Diseases (NIAID), part of NIH.

The study was conducted by the NIAID-funded Inner City Asthma Consortium under the leadership of Matthew C. Altman, M.D., M.Phil., and Daniel J. Jackson, M.D. Dr. Altman is an associate professor in the department of medicine at the University of Washington School of Medicine and an associate scientist at the Benaroya Research Institute at Virginia Mason in Seattle. Dr. Jackson is a professor of pediatrics and medicine in the School of Medicine and Public Health at the University of Wisconsin-Madison.

Asthma is caused by chronic inflammation of the airways. During an asthma attack, the airway lining swells, muscles around the airways contract, and the airways produce extra mucus, substantially narrowing the space for air to move in and out of the lungs. Children who live in low-income urban environments in the United States are at particularly high risk for attack-prone asthma. Asthma attacks provoked by respiratory virus infections—a common trigger—have been studied extensively, but those that occur independently of such infections have not.

In the current study, investigators examined the relationship between air pollutant levels and asthma attacks occurring in the absence of a respiratory virus among 208 children ages 6 to 17 years who had attack-prone asthma and lived in low-income neighborhoods in one of nine U.S. cities. Then the researchers validated the associations they found between air pollutant levels and non-viral asthma attacks in an independent cohort of 189 children ages 6 to 20 years with persistent asthma who also lived in low-income neighborhoods in four U.S. cities.

The investigators followed the children prospectively for up to two respiratory illnesses or approximately six months, whichever came first. Each illness was classified as viral or non-viral and as involving an asthma attack or not. The researchers matched each illness with air quality index values and levels of individual air pollutants recorded by the Environmental Protection Agency in the relevant city on the dates surrounding the illness. The investigators subsequently adjusted their data for city and season to decrease the impact of these variables on the findings.

The scientists found that asthma attacks had a non-viral cause in nearly 30% of children, two to three times the proportion seen in non-urban children, according to previously published reports. These attacks were associated with locally elevated levels of fine particulate matter and ozone in outdoor air. The investigators linked changes in the expression of specific sets of genes that play a role in airway inflammation to elevated levels of these two pollutants by analyzing nasal cell samples obtained from the children during respiratory illnesses. Some of the identified gene-expression patterns suggest that unique biological pathways may be involved in non-viral asthma attacks.

Given the study findings, it will be important to develop and test different strategies to see if they prevent or reduce pollution-associated asthma attacks in urban children. These strategies may include treatments designed to counteract the harmful effects of elevated levels of outdoor air pollutants on airway inflammatory responses linked to non-viral asthma attacks, and devices for personalized monitoring of local outdoor air pollutant levels to inform asthma management.

Reference: MC Altman, et al. Relationships of outdoor air pollutants to non-viral asthma exacerbations and airway inflammatory responses in urban children and adolescents: a population-based study. The Lancet Planetary Health (2023). https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(22)00302-3/fulltext

NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID website.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

NIH...Turning Discovery Into Health®

JOURNAL

The Lancet Planetary Health

Generous parental leave is protective against poorer mental health

Peer-Reviewed Publication

STOCKHOLM UNIVERSITY

Amy Heshmati — IMAGE: AMY HESHMATI, DOCTORAL CANDIDATE AT THE DEPARTMENT OF GLOBAL PUBLIC HEALTH, KAROLINSKA INSTITUTET, SEATED AT THE DEPARTMENT OF PUBLIC HEALTH SCIENCES, STOCKHOLM UNIVERSITY. view more
CREDIT: PHOTO: NIKLAS BJÖRLING

Being on parental leave is protective against poorer mental health particularly among mothers, with evidence of this beneficial effect continuing in later life, according to a systematic review in The Lancet Public Health.

Researchers from the Department of Public Health Sciences at Stockholm University and the Department of Global Public Health at Karolinska Institutet have conducted a systematic review investigating the relationship between parental leave and mental health in parents from an international perspective.

“Becoming a parent can be stressful for both parents. We tend to just think about the enormous hormonal and physical changes experienced by the mother, but we must also think the transition to parenthood is stressful for couples”, says Sol P Juárez, Associate Professor and Senior Lecturer at the Department of Public Health Sciences, Stockholm University, and Principal Investigator of the study.

For example, parents face challenges related to child-care, career uncertainties and financial pressures due to reduced income.

“This is perhaps why mental disorders after childbirth are relatively common, it is usually said that 10 to 20 percent of the mothers and up to 10 percent of the fathers are affected. Therefore, we wanted to systematically examine all the published scientific evidence to see whether parental leave may help alleviate mental health symptoms among parents”, says Sol P Juárez.

The review concludes that parental leave was protective against poorer mental health including depressive symptoms, general mental health, psychological distress, burnout and mental healthcare use, particularly for mothers.

“However, the beneficial effects are associated with more generous parental leave schemes, for example with longer duration of leave”, highlights Amy Heshmati, doctoral candidate and the first author of the study.

The researchers searched five online databases until August 29, 2022. A total of 45 studies were included in the study.

“This is the most comprehensive systematic review on this topic to date. We have looked for a connection between different aspects of parental leave, such as length of leave and whether leave was paid or unpaid, and their associations with mental health in both mothers and fathers. We even investigated the indirect effect of one parent taking parental leave on their partner’s mental health”, says Amy Heshmati.

“An interesting finding is that the beneficial effects are not only observed shortly after childbirth, but that these protective effects of parental leave can continue into later life for mothers,” say Helena Honkaniemi, postdoctoral researcher and author of the review.

Findings among fathers were inconclusive.
“Less research has been done on fathers and still this research suggests that fathers have improved mental health with parental leave policies that offer adequate wage replacement or incentives, such as uptake quotas”, adds Helena Honkaniemi.

The review demonstrates that generous parental leave may help to alleviate or prevent mental health symptoms, especially for mothers, a finding that is highly relevant from a policy perspective.

More information
“The effect of parental leave on parents’ mental health: a systematic review” is published in The Lancet Public Health https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(22)00311-5/fulltext

The systematic review summarised the findings of 45 studies that were conducted in the following countries or regions:
Europe: Belgium, Denmark, France, Norway, Ireland, Italy, Spain, Sweden, Germany.
North America: Canada, USA.
Other countries: Australia, Chile and Japan.

Contact
Amy Heshmati, doctoral candidate at the Department of Global Public Health, Karolinska Institutet, seated at the Department of Public Health Sciences, Stockholm University.
E-mail: amy.heshmati@su.se

The study’s co-authors:
Sol P Juárez, Associate Professor and Senior Lecturer, Department of Public Health Sciences, Stockholm University.
Email: sol.juarez@su.se
Helena Honkaniemi, postdoctoral researcher, Department of Public Health Sciences, Stockholm University.
Email: helena.honkaniemi@su.se

Research grant: Swedish Research Council (2018–01825)
Research project: The unintended consequences of Swedish parental leave policy (ParLeHealth): A health perspective www.su.se/publichealth/ParLeHealth

JOURNAL

The Lancet Public Health

ARTICLE TITLE

The effect of parental leave on parents’ mental health: a systematic review

ARTICLE PUBLICATION DATE

3-Jan-2023