Scale of impact of maternal Zika virus infection on offspring in early life

Approximately one third of children born to mothers infected with Zika virus whilst pregnant presented with abnormalities consistent with Congenital Zika Syndrome in the first years of life.

Peer-Reviewed Publication

LONDON SCHOOL OF HYGIENE & TROPICAL MEDICINE

Approximately one third of children born to mothers infected with Zika virus during their pregnancy present with at least one abnormality consistent with Congenital Zika Syndrome in the first years of their life, according to new research. 

The findings — based on the pooled analysis of 13 studies investigating paediatric outcomes among over 1,500 pregnancies affected by Zika virus during the 2015–2017 epidemic in Brazil — improve our understanding of the risks associated with prenatal Zika virus infections, with important public health implications.

Following the emergence of a microcephaly epidemic in Brazil in 2015, the possibility of an association between increased transmission of Zika virus and potential birth defects emerged.

Although studies have investigated potential adverse pregnancy outcomes following infection, small sample sizes, high variability between estimates and reliance on routine surveillance data have limited our understanding of the true extent of this risk.

In this study, the team — comprised of researchers from 26 institutions in Brazil in collaboration with the London School of Hygiene & Tropical Medicine (LSHTM) and the University of California at Los Angeles — analysed data on the offspring of 1,548 pregnant women from 13 cohort studies in the Zika Brazilian Cohorts Consortium. These data comprise all four regions in Brazil affected by the epidemic between 2015 and 2017, with prenatal infection confirmed in the laboratory using genetic testing and potential adverse outcomes assessed at the individual level and harmonised across studies. 

Overall, the most frequently observed manifestations of Congenital Zika Syndrome among the children included functional neurological impairments, neuroimaging abnormalities, alterations in hearing and vision, and microcephaly.  The results provide evidence that the congenital abnormalities were more likely to present in isolation, with less than 0.1% of exposed offspring experiencing two abnormalities simultaneously.

Risk of offspring presenting with microcephaly — a neurological condition whereby the baby’s head is smaller than expected for their age and sex— was found to be approximately 2.6% at birth or when first evaluated, increasing to 4.0% across the early preschool years. This risk remained relatively consistent across study sites, with no apparent variation according to socioeconomic conditions.

The research is published in The Lancet Regional Health – Americas.

Lead author Professor Ricardo Arraes de Alencar Ximenes, from the Federal University of Pernambuco in Brazil commented: “These results highlight the importance of having multi-disciplinary health teams available near the time of birth to evaluate children with prenatal exposure to Zika virus exposure and to refer them, as needed, to specialized follow-up care that can provide support for known disabilities and diagnosis of late manifestations.”

Co-author on the study and Associate Professor of Epidemiology at LSHTM, Dr Elizabeth Brickley,  also said: “These findings underscore the continued need to develop a safe and effective vaccine for preventing Zika virus infections during pregnancy.  While gaps in population level immunity to the virus persist, the threat of a Zika virus re-emergence remains a concern for public health.”

Looking forward, the researchers emphasize that additional studies with longer follow-up times will be needed. Potential avenues for investigation include assessing the risk of hospitalization and death for children with microcephaly as they age, and in those without microcephaly, examining risks of other complications, such as those linked to behavioural or neuropsychomotor development. 

 

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JOURNAL

The Lancet Regional Health - Americas

ARTICLE TITLE

Risk of adverse outcomes in offspring with RT-PCR confirmed prenatal Zika virus exposure: An individual participant data meta-analysis of 13 cohorts in the Zika Brazilian Cohorts Consortium

ARTICLE PUBLICATION DATE

28-Nov-2022

Cracking open a fossil bone reveals rapid juvenile growth in early tetrapods

Peer-Reviewed Publication

HARVARD UNIVERSITY, DEPARTMENT OF ORGANISMIC AND EVOLUTIONARY BIOLOGY

 

IMAGE: A SKELETAL RECONSTRUCTION OF WHATCHEERIA DELTAE (CREDIT B. OTOO). THIS STUDY MADE THIN-SECTIONS OF WHATCHEERIA THIGH BONES (FEMORA) INCLUDING A JUVENILE FEMUR THAT REVEALED A TYPE OF BONE THAT IS ASSOCIATED WITH ELEVATED GROWTH RATES. IN HISTOLOGICAL SECTION AND UNDER POLARIZED LIGHT, THIS DISORGANIZED TISSUE IN JUVENILE WHATCHEERIA FEMORA SUGGEST THAT THIS ANIMAL GREW QUICKLY EARLY IN ITS LIFETIME. view more 

CREDIT: CREDIT: B. OTOO

The rise of tetrapods (four-limbed vertebrates) is one of the iconic evolutionary transitions preserved in the fossil record. These animals, which lived about 385 to 320 million years ago during the Devonian and Carboniferous periods of Earth’s history, set the stage for the evolution and diversification of all other terrestrial vertebrates as we know them today, including amphibians, reptiles, birds, and mammals like humans.

It was long thought that these early animals grew very slowly throughout their lifetime, gradually getting bigger and bigger, similar to a modern salamander. However, in a new study in Communications Biology researchers in the Department of Organismic and Evolutionary Biology (OEB) at Harvard University, the Committee on Evolutionary Biology (CEB) at the University of Chicago, and the Field Museum of Natural History cracked open the fossil femora (thigh) bone of a range of growth stages in the early tetrapod, Whatcheeria deltae, and found evidence that the animal grew quickly into adulthood, calling into question conventional wisdom on tetrapod growth.

Lead author Megan R. Whitney, former postdoctoral researcher in OEB, and senior author Professor Stephanie E. Pierce (OEB), Curator of Vertebrate Paleontology in the Museum of Comparative Zoology, have been studying early tetrapods to better understand how they grew, which helps to provide more clarity into the life histories of the animals. “Examining these fossils is like reading a storybook and we are trying to read as many chapters as possible by looking at how juveniles grow building up to adulthood,” said Whitney, “because of where Whatcheeria sits in the early tetrapod family tree we wanted to target this animal and look at its storybook at different stages of life.”

The rarity of early tetrapod samples in the fossil record is a challenge for scientists who are often working from incomplete fossil bodies or species groups. Whatcheeria, however, is a unique exception because it is represented by hundreds of bones from several individuals of different sizes that were all preserved in one locality in Iowa. “Whatcheeria is one of the stars of our paleontology collection,” said co-author Dr. Ken Angielczyk, MacArthur Curator of Paleomammology at the Field Museum. “It is one of the best represented early tetrapods in the fossil record, and the abundance of material lets us ask questions about its biology that are impossible for nearly all of its contemporaries.”

Whatcheeria resembled an over-sized salamander with robust legs and arms that supported its weight on land, yet had other anatomical features that suggest it was still bound to water. Whatcheeria lived on the margins of a lowland terrestrial lake at the interface of water and land between about 331 and 326 million years ago, suggesting these animals spent time in both aquatic and terrestrial habitats.

Co-author Benjamin K.A. Otoo (CEB) and Angielczyk provided nine representative samples spanning the known size classes of Whatcheeria from juvenile to adult. Whitney and Pierce then made wafer thin slices of the fossil to examine the microscopic structure of the bone tissues in the thigh bones (femora) by placing the wafers under a polarized light microscope. When they cracked open and examined the juvenile bone sample they found evidence of fibrolamellar bone, which is primary bone tissue associated with fast growth.

“I have a very distinct memory of jumping on slack with Stephanie [Pierce] and saying this breaks all of the rules that we thought of for how growth is evolving in these early tetrapods,” said Whitney.

Pierce and Whitney recalled one of their earlier studies on the tetrapod Greererpeton, a slightly younger Carboniferous early tetrapod, which showed a very different growth strategy of moderate growth with a period of no growth for a long period of time. They hypothesized this could be due to migration of the animal between bodies of water.

“We saw this in multiple individuals of Greererpeton, so when we looked at the bones of Whatcheeria and found something completely different again, we knew these animals and their life histories must be affected by their interactions with their environment and their places in their ancient ecosystems,” said Pierce.

Whatcheeria is one of the largest animals recovered from the fossil site in Iowa. The large size combined with the evidence of fibrolamellar bone led researchers to hypothesize that Whatcheeria may have grown fast to quickly reach the large size necessary to be a top predator in its environment.

“If you’re going to be a top predator, a very large animal, it can be a competitive advantage to get big quickly as it makes it easier to hunt other animals, and harder for other predators to hunt you,” said Pierce. “It can also be a beneficial survival strategy when living in unpredictable environments, such as the lake system Whatcheeria inhabited, which went through seasonal dying periods.”

The assumption has always been that only amniotes (reptiles, birds and mammals) deposited fibrolamellar bone consistent with fast growth and that slow growth was ancestral for tetrapods. But as Whitney and Pierce discovered, this bone tissue type evolved close to the origin of the first tetrapods, much earlier than anybody ever expected.

“Whatcheeria’s elevated growth rates as a juvenile shows us that maybe slow and steady growth throughout a lifetime is not actually the ancestral condition for all tetrapods,” said Whitney, “and this finding contributes to the diversity of patterns we see as we continue to sample more and more early tetrapods. We’re seeing they are not all slow, sluggish animals, but are incredibly diverse in their own right.”

Whitney, currently Assistant Professor at Loyola University Chicago, and Pierce plan to continue investigating the bone tissue microstructure of early tetrapods to reveal their life histories and how they relate to their ecological niche, specifically targeting animals found earlier in the fossil record than Whatcheeria. “We recently gathered bone histology data on a relative of Whatcheeria using advanced synchrotron technology,” said Pierce, “and our exciting preliminary results point to yet another unexpected growth strategy.”

The growth of Whatcheeria at four different stages of life were studied by examining the kind of bone present at specimen representatives from each stage. Bone organization can be used as a proxy for growth rate and this study reports disorganized, fibrolamellar bone in juvenile specimens and more organized bone in adult specimens. This pattern of fast rapid growth early in the life of Whatcheeria, followed by slow and reduced growth in the adults is a new finding in early tetrapods. This finding suggests that rather than growing slow-and-steady throughout their lives, at least some early tetrapods were growing rapidly to reach their adult size.

CREDIT

Skeletal reconstruction by B. Otoo.

Under polarized light, an image of the fibrolamellar bone described in the youngest specimens sampled in this study. The vascular spaces (porous, purple spaces) and bone tissue (pink) are haphazardly organized suggesting rapid overall growth of the animal.

 

Under polarized light, an image of the fibrolamellar bone at the outer surface of the femur of the youngest specimens sampled in this study. The vascular spaces (porous, purple spaces) and bone tissue (pink) are haphazardly organized suggesting rapid overall growth of the animal.

CREDIT

Credit: M. Whitney

JOURNAL

Communications Biology

ARTICLE TITLE

Fossil bone histology reveals ancient origins for rapid juvenile growth in tetrapods

Study using DNA analysis of sacrificial spider monkey suggests Mesoamerican diplomacy

Peer-Reviewed Publication

UNIVERSITY OF OKLAHOMA

 

IMAGE: UNIVERSITY OF OKLAHOMA STUDENTS WORK IN THE LABORATORIES OF MOLECULAR ANTHROPOLOGY AND MICROBIOME RESEARCH ANCIENT DNA LAB. view more 

CREDIT: PHOTO BY ROBIN SINGLETON

NORMAN, OKLA. – A multimethod archaeological study of a spider monkey sacrificed at Teotihuacàn, located approximately 25 miles from Mexico City, provides the earliest evidence of primate captivity and translocation in the Americas over 1,500 years ago.

Researchers at the University of Oklahoma’s Laboratories of Molecular Anthropology and Microbiome Research led the genetic analysis of the spider monkey’s skeleton. The OU team includes study co-authors Courtney Hofman, Ph.D., President’s Associates Presidential Professor in the Department of Anthropology, Dodge Family College of Arts and Sciences, with graduate student Robin Singleton and laboratory technician Karissa Hughes.

“Geoffrey’s spider monkeys are not found near Teotihuacàn today,” Hofman said. “Ancient DNA analysis of this spider monkey sought to identify the subspecies of the spider monkey, which can provide insight into ancient trade networks.”

“We were able to confirm that the spider monkey was most closely related to two endangered populations, the Mexican and the Yucatan spider monkey subspecies,” she added. “Using additional lines of evidence, including isotopic analysis, we hypothesized that this animal was of the Mexican subspecies, which today lives in parts of Mexico, Guatemala and Honduras. The presence of this animal in the central Mexican city of Teotihuacàn suggests that there was greater interaction with the Maya than previously understood and perhaps this spider monkey was a diplomatic gift.” 

The study, Earliest evidence of primate captivity and translocation supports gift diplomacy between Teotihuacan and the Maya, was published Nov. 21 in the journal Proceedings of the National Academy of Sciences and was featured in Science.

Nawa Sugiyama, assistant professor of anthropology at the University of California, Riverside, is the first author. In addition to the OU team, co-authors include researchers from Arizona State University; the Archéologie des Amériques in Paris, France; the Smithsonian Museum Conservation Institute; the RIKEN Institute in Kobe, Japan; and Washington State University.

Courtney Hofman, professor of anthropology at the University of Oklahoma, and Laboratories of Molecular Anthropology and Microbiome Research lab technician Karissa Hughes work in OU’s LMAMR ancient DNA lab.

CREDIT

Photo by Robin Singleton

University of Oklahoma graduate student Robin Singleton examines material from Teotihuacàn under a microscope in the Laboratories of Molecular Anthropology and Microbiome Research ancient DNA lab.

CREDIT

Photo by Courtney Hofman.

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JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2212431119 

ARTICLE TITLE

Earliest evidence of primate captivity and translocation supports gift diplomacy between Teotihuacan and the Maya

Discovery of antibody structure could lead to treatment for Crimean Congo Hemorrhagic Fever virus

Study provides insights into fighting broad range of pathogen’s viral strains

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - RIVERSIDE

RIVERSIDE, Calif. -- A research team led by the University of California, Riverside, has discovered important details about how therapeutically relevant human monoclonal antibodies can protect against Crimean Congo Hemorrhagic Fever virus, or CCHFV. Their work, which appears online in the journal Nature Communications, could lead to the development of targeted therapeutics for infected patients.  

An emerging zoonotic disease with a propensity to spread, CCHF is considered a priority pathogen by the World Health Organization, or WHO. CCHF outbreaks have a mortality rate of up to 40%. Originally described in Crimea in 1944–1945, and decades later in the Congo, the virus has recently spread to Western Europe through ticks carried by migratory birds. The disease is already endemic in Africa, the Balkans, the Middle East, and some Asian countries. CCHFV is designated as a biosafety level 4 pathogen (the highest level of biocontainment) and is a Category A bioterrorism/biological warfare agent. There is no vaccine to help prevent infection and therapeutics are lacking. 

Scott D. Pegan, a professor of biomedical sciences in the UCR School of Medicine, collaborated on this study with the United States Army Medical Research Institute of Infectious Diseases, or USAMRIID, which studies CCHFV because of the threat it poses to military personnel around the world. They examined monoclonal antibodies, or mAbs, which are proteins that bind to antigens — foreign substances that enter the body and cause the immune system to mount a protective response. 

In a previous publication, USAMRIID scientists Joseph W. Golden and Aura R. Garrison reported that an antibody called 13G8 protected mice from lethal CCHFV when administered post-infection. They provided Pegan with the sequence information for that antibody, clearing the way for UCR to “humanize” it and conduct further research.

“The USAMRIID study showed that the mouse mAb, 13G8, helps the immune system clear the infection,” Pegan said. “We knew 13G8 binds to a viral glycoprotein called GP38, but it wasn’t clear where that binding took place. So we analyzed the structure to gain an understanding of how it works and pinpoint exactly where the binding occurs. This knowledge sheds light on the potential of these mAbs to be effective against a broad range of CCHF viral strains.”

Members of Pegan’s research team were also able to obtain serum from patients who contracted CCHF in Turkey. The researchers isolated seven mAbs from a CCHFV survivor and identified two new antigenic sites on GP38. They then solved the structure of GP38 bound to one of the seven non-neutralizing human antibodies, in addition to 13G8. Knowledge of the structure of this complex can confer a clinical benefit as well, according to the authors. 

“This structural information further characterizes GP38 as an antigen of interest for vaccination studies, while also advancing mAb development toward CCHFV,” Garrison said. “The therapeutic role for non-neutralizing antibodies in preventing disease is becoming more evident for high-risk pathogens such as Ebola, Lassa, and Nipah virus.” 

Pegan explained that CCHFV has a tri-segmented RNA genome, consisting of a large, medium, and small segment. In 2006, GP38 was identified as a component of the medium fragment by the Special Pathogens Branch at the Centers for Disease Control and Prevention, or CDC, which also contributed to the Nature Communications study. The function of GP38 and its role in CCHFV infection remain unclear. 

“We know that targeting GP38 stops CCHFV’s progression, but no one is fully certain about how it works,” Pegan said. “We would like to know more about its mechanism of action so that specific and effective therapeutics can be developed.”

The research was funded by grants to Pegan and his CDC partner, Éric Bergeron, from the National Institutes of Health and the Department of Defense. Golden and Garrison were supported by the Military Infectious Diseases Research Program. 

Pegan, Garrison, and Bergeron were joined in the study by Elif Karaaslan, Jack McGuire, and David Gonzalez of UC Riverside; Ian A. Durie, Suzanne Enos, and Jarrod J. Mousa of the University of Georgia; Zahra R. Tehrani and Mohammad M. Sajadi of the University of Maryland School of Medicine; Teresa E. Sorvillo, Stephen R. Welch, Markus H. Kainulainen, Jessica R. Harmon, Jessica R. Spengler, and Christina F. Spiropoulou of the CDC’s Special Pathogens Branch; Joseph W. Golden of USAMRIID; Iftihar Koksal of Acibadem University Atakent Hospital, Turkey;  Gurdal Yilmaz, Sanaz Hamidi, and Cansu Albay of Karasdeniz Technical University School of Medicine, Turkey; and Hanife Nur Karakoc of Bitlis State Hospital, Turkey. 

About the University of California, Riverside:

The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment is more than 26,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual impact of more than $2.7 billion on the U.S. economy. More information.

About the U.S. Army Medical Research Institute of Infectious Diseases:

Since 1969, USAMRIID has provided leading edge medical capabilities to deter and defend against current and emerging biological threat agents. The Institute is the only laboratory in the Department of Defense equipped to safely study highly hazardous viruses requiring maximum containment at Biosafety Level 4. Research conducted at USAMRIID leads to vaccines, drugs, diagnostics, and training programs that protect both Warfighters and civilians. The Institute's unique science and technology base serves not only to address current threats to our Armed Forces but is an essential element in the medical response to any future biological threats that may confront our nation. More information.

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JOURNAL

Nature Communications

DOI

10.1038/s41467-022-34923-0 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

10.1038/s41467-022-34923-0

ARTICLE PUBLICATION DATE

26-Nov-2022

COI STATEMENT

A.R.G. and J.W.G. are inventors on a patent application related to the use of mAb 13G8 as a therapeutic, PCT/US2020/012621. The remaining authors declare no competing interests.

University of Cincinnati research examines workplace stress in the aftermath of the COVID-19 pandemic

Certain professions report more stress than others

Peer-Reviewed Publication

UNIVERSITY OF CINCINNATI

Chronic stress is associated with a wide range of health disparities, but the examination of workplace stress has been minimal in many occupations.

A new study from the University of Cincinnati examined the impact of workplace stress and provided insights for organizations to explore ways to reduce workplace stress for a better and healthier working environment.

The study had two parts: a survey in which respondents described their experiences of workplace stress during the COVID-19 pandemic and a quantitative study using saliva cortisol as a biomarker of stress along with a stress diary to find out where and when workplace stress commonly occurred.

The first part of the study, published in the Annals of Work Exposures and Health, detailed increased stress levels, stressor events and other perceptions of stress from at-risk workers during COVID-19.

“Stress is often overlooked in the workplace, and we tend to look at traditional health hazards like chemical exposure to gases and particles or physical hazards like falls, cuts and burns,” says Jun Wang, PhD, of the Department of Environmental and Public Health Sciences in the UC College of Medicine and faculty mentor on the study.

“Stress, even though not as ‘tangible’ as chemical or physical hazards, can deeply affect workers’ mental health and lead to workplace injury and illness. Workplace stress issues were amplified during COVID-19 because many people worked from home. Many health care professionals were also overloaded due to the increased number of patients and less resources.”

The UC research developed an in-depth, work-related stress survey that incorporated many aspects of work conditions, work context, work-life balance and the health of employer-employee relationships with a focus on COVID-19-related stressors. The cross-sectional survey was completed by 670 workers in a variety of clearly distinguished sectors, including manual labor, business settings, health care and education.

More than 50% of the participants reported experiencing an increased workload since the onset of the pandemic with some sectors, like health care, reporting an increased workload more frequently, at 80%. Around 55% of respondents believed they could be exposed to COVID-19 in their workplace, ranging from 52% of business/office service workers to 77% of health care workers, and this perception of COVID-19 exposure led as the greatest stressor.

“As workplaces navigate past the pandemic, occupational stress should be addressed head-on through providing expanded resources to assure work stress associated with future pandemics are mitigated appropriately,” says Wang. “Whether the stressor is associated with irregular shift work or psychosocial aspects, many of these stressors have the possibility to become exacerbated by external factors such as pandemics or economic downturns which we are experiencing right now.”

The second part of the study, published in the International Journal of Environmental Research and Public Health, found a relationship between occupational stress and increased salivary cortisol levels. For the study, 15 participants were recruited via email and social media. Each was given a kit containing a blank work stress diary, a sampling log, study protocol and nine saliva collection vials.

“As the body’s main stress hormone, cortisol is released each day, with levels typically highest in the morning and tapering off throughout the day,” says Thomas Gerding, PhD candidate and primary student investigator in this study. “Traditionally, cortisol-based stress research required [participants] to come to a clinic around noon and [have] their saliva collected by a professional. This method is not suitable to identify the fluctuation of cortisol throughout the day, and it is hard to correlate them to specific stressors such as workplace conflict and work-life balance issues.”

During three consecutive working days, participants were asked to document anything causing stress during working hours in the diary which included sections for occupation, date, time of day, intensity of stress on a scale of 0 to 5 (no stress to the highest level of stress), stress duration, situation description, triggering event, if applicable, and any emotional behavioral reaction. They were also asked to describe whether the day would be considered typical of their job.

“The whole idea of this project is to create a way for people to investigate their stress level by using this kit themselves, developing self-measures of saliva,” Wang says. “They collect the saliva in the tube, then they freeze it, and they also document what is likely the stressor event. If you feel stress, what is it? What is the nature of the stress?”

Wang says measuring cortisol changes may provide insights into types of occupational stressors and how these may be minimized. The goal of subsequent research in this area is to establish a measurable baseline for stress, with an emphasis on high stress occupations such as home health care workers or firefighters.

“In the future we will try to include a way to measure the baseline for each person so when they are comparing their stress level, they are comparing to their baseline,” Wang says.

“Stress is something that has been understudied in the past. A lot of people don’t take stress as critical as other aspects of the workplace environment. When people have stress or a mental health issue, like depression, a lot of times people don’t talk about those things. Moving forward, it is critical to build a healthier workplace with fewer hazards and less stress.”

This study is sponsored by the National Institute for Occupational Safety and Health (NIOSH) through various mechanisms, although the study conclusions do not necessarily represent the official stance of NIOSH. NIOSH’s largest research office is located several miles from the University of Cincinnati campus. In recent years, NIOSH has been closely collaborating with researchers at the University of Cincinnati on solving emerging workplace issues. 

 

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JOURNAL

Annals of Work Exposures and Health

DOI

10.1093/annweh/wxac076 

METHOD OF RESEARCH

Survey

SUBJECT OF RESEARCH

People

ARTICLE TITLE

An Investigation into Occupational Related Stress of At-Risk Workers During COVID-19

New analysis finds pandemic didn’t dampen deforestation

Peer-Reviewed Publication

THE ALLIANCE OF BIOVERSITY INTERNATIONAL AND THE INTERNATIONAL CENTER FOR TROPICAL AGRICULTURE

 

IMAGE: DEFORESTATION GLOBALLY PROCEEDED MORE OR LESS AS EXPECTED FROM THE TRENDS ESTABLISHED OVER THE LAST 15 YEARS, ACCORDING TO A RECENT STUDY view more 

CREDIT: ALLIANCE OF BIOVERSITY AND CIAT / N.PALMER

Despite the massive upheavals in the first year of the COVID-19 pandemic, deforestation globally proceeded more or less as expected from the trends established over the last 15 years, according to a recent study from researchers at the Alliance of Bioversity International and CIAT.

In the paper “Has global deforestation accelerated due to the COVID-19 pandemic?” published in mid-November 2022, the researchers used historical deforestation data (2004–2019) from the Terra-i pantropical land cover change monitoring system to project expected deforestation trends for 2020.

Analysis of tree cover loss over time was used to determine whether deforestation observed in 2020 deviated from expected trajectories after the first COVID-19 cases were reported; both at the regional level for the Americas, Africa and Asia and at the country level for Brazil, Colombia, Peru, the Democratic Republic of the Congo and Indonesia.

“It was not particularly surprising to see little change,”

says Janelle Sylvester,  who is the corresponding author of the study and a Research Fellow at the Alliance.

She said that deforestation rates likely did not drastically change for many reasons. For one, it is probable that the complex dynamics driving deforestation before the pandemic persisted unimpacted by the lockdowns.

“For example, illegal deforestation in areas where there was minimal state (governmental) presence before the pandemic would likely continue during lockdowns,” she said. 

Moreover, she explained that “global-level macroeconomic forces related to changes in demand and supply paired with national economic stimulus packages could have balanced out economic pressures that were being placed on forests.”

Louis Reymondin, who co-leads the Digital transformation of the agri-food systems research theme for the Alliance of Bioversity International and CIAT also said that the finding wasn’t surprising, given that deforestation is heavily driven by livestock grazing and that demand for those products continued during the lockdowns in 2020.

“There were changes in food consumption habits, but usually it was towards processed foods and a reliance on industrialized agriculture,” he said, “The disruption needed to stop deforestation is about changing consumer behavior, changing the food system… and that's something that countries and governments and scientists are trying to push forward.”

Jonathan Céspedes, the lead author of the study, an Alliance of Bioversity and CIAT research assistant during the study and now a 2nd year Phd Student at Institut Polytechnique de Paris says that his task was to evaluate deforestation and COVID-19 data in order to determine possible relationships between both variables.

“It is key to take into account that the spatial scale of this study is global; therefore, the next stage is to evaluate sub-national and local scales, where probably the results may be different,” Céspedes said.

Sylvester said that to get a genuine snapshot of the impact, more research would be required, as national economic recovery efforts in response to the pandemic may have longer-term effects on deforestation that are not captured in this study limited to 2020.

“All in all we see that deforestation trends in most countries followed their expected trajectories; however, to really understand the effects of the pandemic on deforestation we will have to look at a longer time period, say three years or more, in order to understand how national economic recovery efforts impact forest cover,” Sylvester said.

The Alliance’s Role

Sylvester explained that the previous expertise of the Alliance was key in reaching these conclusions.

“The Alliance of Bioversity and CIAT has a great team working with the Terra-i deforestation monitoring system, their expertise working with these deforestation alerts contributed immensely to this study,” Sylvester said.

Augusto Castro-Nunez, the lead supervisor and a senior scientist for low emissions food systems at the Alliance Bioversity and CIAT said that the Alliance is well-known for its many years of experience monitoring forest cover changes.

“More recently the Alliance has developed the capacities to not only monitor the changes but to understand the underlying drivers behind them,” he said, “We have been publishing on this topic for many years focusing on conflict-affected settings like Colombia and more recently, we have been studying the food system drivers of deforestation with the FAO as a partner.”

 

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• Learn more by reading the paper.

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JOURNAL

Journal of Forestry Research

DOI

10.1007/s11676-022-01561-7 

METHOD OF RESEARCH

Survey

ARTICLE TITLE

Has global deforestation accelerated due to the COVID-19 pandemic?

Researchers discover root exudates have surprising and counterintuitive impact on soil carbon storage

Peer-Reviewed Publication

HARVARD UNIVERSITY, DEPARTMENT OF ORGANISMIC AND EVOLUTIONARY BIOLOGY

 

IMAGE: CONCEPTUAL DIAGRAM ILLUSTRATING THE EFFECTS OF EXUDATION RATE (A) AND COMPOSITION (B) ON MINERAL-ASSOCIATED ORGANIC MATTER (MAOM) FORMATION AND LOSS AS MEDIATED BY MICROBIAL BIOMASS CARBON (MBC). view more 

CREDIT: NIKHIL CHARI

Ecosystem ecology studies often focus on what’s happening to plants above ground, for instance exploring photosynthesis or water loss in leaves. But what is happening below the ground in plant roots is equally important when evaluating ecosystem processes.

In a new study in Nature Geoscience researchers in the Department of Organismic and Evolutionary Biology at Harvard University examined root exudates and their impact on soil carbon storage revealing surprising and counterintuitive results.

Root exudates are organic carbon compounds (such as simple sugars, organic acids, and amino acids) released from living plant roots into the soil. These small molecules can bind directly to soil minerals, making them important regulators of soil carbon formation and loss. Unlike plant litter (such as leaves and roots), which must be decomposed before it can affect the soil carbon pool, root exudates can have immediate effects on mineral-associated organic matter (MAOM), which contains long-cycling, “stable” soil carbon.

Several studies show that anthropogenically elevated atmospheric CO2 concentrations are likely to increase the rate of plant root exudation and change the chemical composition of root exudates. Lead author Nikhil R. Chari, Ph.D. candidate, and senior author Professor Benton N. Taylor tested how these changes may affect soil carbon by examining how changing the rate of root exudation and the composition of exudates  affected native soil-carbon dynamics in a temperate forest.

Chari and Taylor collected soil cores from Harvard Forest, a temperate hardwood forest in central Massachusetts, and incubated them directly in centrifuge tubes. They then fabricated three different carbon-13 root exudate “cocktails” of simple sugar, organic acid, and amino acid. They delivered the “cocktails” to the soil cores via “artificial roots”  at two different rates over a thirty-day period. Unlike other studies, Chari and Taylor did not use homogenized or artificial soils. Their sampling method preserved large amounts of heterogeneity in soil carbon and microbial communities present in the forest.

“We wanted to know if these mechanisms were having an effect at ecologically meaningful scales,” said Chari. “We used intact soil cores to test if the effect of root exudates would overcome the natural heterogeneity in the system.”

The researchers measured both initial and final carbon stocks in the cores. They found that contributions of root exudates to soil carbon were driven by contributions to the long-cycling MAOM fraction. MAOM are microscopic coatings on soil particles made mostly of the byproducts of bacteria and fungi. MAOM stays in the soil for decades meaning it can maintain carbon in soil for a very long time.

At higher rates of root exudation the MAOM carbon pool did not change even as root exudate contributions to MAOM increased. But at lower rates of root exudation Chari and Taylor observed net MAOM carbon accumulation, even though the exudate contributions were not as great.

“You would think that if you increase the rate of root exudation you would increase carbon input into the soil forming more soil carbon,” said Chari, “but we found instead an opposite effect that offset the increase in carbon.”

The researchers refer to this as the priming effect. Priming occurs when the input of new soil carbon prompts the decomposition of old soil carbon. Enhanced rates of root exudation appeared to increase rates of MAOM priming relative to rates of MAOM formation.

“First principles would suggest that the more carbon we push into the soil via exudation, the more carbon is going to accumulate in these MAOM fractions. When, in fact, that doesn't seem to be the case,” said Taylor. “In reality, you get more MAOM formation, but you also get more loss of it and it balances out. You don't actually get more carbon sticking around in the soil, even when you’re pushing more in.”

Chari and Taylor also found the different exudate compounds each had different effects on the soil carbon. Glucose (simple sugar) produced higher MAOM turnover both in formation and loss, but there was no net accumulation of MAOM. While succinic acid (organic acid) and aspartic acid (amino acid) drove lower rates of MAOM formation, but did result in a net MAOM carbon accumulation. Interestingly, the researchers found that amino acids had a particularly strong positive effect in increasing microbial biomass carbon formation, while organic acids did not. These findings again suggests the larger microbial community enhances the microbial priming effect. The results further validate that predicted increases in root exudation rates and a shift toward simple sugars caused by global change may reduce soil’s carbon storage capacity.

“These changes are happening ubiquitously below the soil surface, yet even tiny changes in this process can have huge implication for soil carbon storage,” said Taylor. “People know that processes in a leaf are important, but every root below our feet has a huge impact on carbon in the soil. And elevated CO2, warming, or other climate change drivers, could cause soil carbon loss to increase disproportionately to soil carbon formation.”

Going forward, Chari and Taylor continue to measure changes in the rate and composition of root exudates under elevated CO2 and warming in a variety of different ecosystems, including temperate forests, grasslands, and corn and soybean agricultural fields.

Intact soil cores were incubated in centrifuge tubes (blue caps) with artificial roots connected to a manual pump system delivering different exudate solutions to each core.

CREDIT

Nikhil Chari

JOURNAL

Nature Geoscience

DOI

10.1038/s41561-022-01079-x 

ARTICLE TITLE

Soil organic matter formation and loss are mediated by rood exudates in a temperate forest

ARTICLE PUBLICATION DATE

28-Nov-2022