Sink or Swim: the fate of sinking tectonic plates depends on their ancient tectonic histories

New findings provide a greater understanding of how tectonic plates move

Peer-Reviewed Publication

Woods Hole Oceanographic Institution

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Successfully recovered ocean bottom seismometers onboard the James Cook from both the US Scripps and German DEPAS pools.

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Credit: (Credit: Stephen Hick, U. College London)

Woods Hole, Mass. — Newly published research has revealed that compositional rock anomalies within oceanic plates caused by ancient tectonics influence the trajectory and speed of the plates as they plunge deep into Earth’s mantle.

Between depths of 410 and 660 kilometers lies the mantle transition zone (MTZ), a critical region acting as a gateway for materials entering Earth's deeper mantle. Large distributions of basalt rock compositions within the MTZ can cause subducting plates—ones that slide beneath other—to slow and/or stagnate within this zone, instead of descending directly into the lower mantle. Although basalt reservoirs have previously been discovered in the MTZ, their origins have remained unclear.

An international team of seismologists led by the University of Southampton (and now at the Woods Hole Oceanographic Institution) has provided evidence of an extremely thick MTZ, which can only be explained by a large  basaltic rock composition, suggesting that, in certain regions, entire oceanic slabs—approximately 100 kilometers thick—can possess significant basaltic material.

The findings, published in the journal Nature, provide a greater understanding of plate subduction, which recycles surface materials and volatile elements deep into the Earth's interior, sustaining long-term climate stability, atmospheric balance, and the habitability of our planet over billions of years.

This groundbreaking research is part of the VoiLA (Volatiles in the Lesser Antilles) project, in which the team deployed 34 seismometers on the ocean floor beneath the Lesser Antilles.

"This is the first large scale ocean bottom seismic experiment conducted at an Atlantic subduction zone," said Dr. Catherine Rychert, formerly an Associate Professor at the University of Southampton and currently at the Woods Hole Oceanographic Institution. "We were very surprised to find an unexpected and exceptionally thick—approximately 330 kilometers—mantle transition zone beneath the Antilles, which makes it one of the thickest transition zones observed worldwide. Although the Caribbean is well-known for its sunshine and beaches, it now has a new claim to fame in the world of plate tectonics."

“It’s wild to think that in some ways tectonic plates have a ‘memory’ and that affects the way the plates drive mantle convection and mix material back into the Earth,” said Dr. Nick Harmon, formerly an Associate Professor at the University of Southampton and currently at the Woods Hole Oceanographic Institution.

“It’s wild to think that in some ways tectonic plates have a ‘memory’ and that affects the way the plates drive mantle convection and mix material back into the Earth,” said Dr. Nick Harmon, formerly an Associate Professor at the University of Southampton and currently at the Woods Hole Oceanographic Institution.

Lead author, Dr. Xusong Yang, a former visiting scholar at the University of Southampton and currently at University of Miami, emphasized, "We cannot overlook the inherited compositional heterogeneity of subducting oceanic slabs. It may greatly influence their ultimate fate in Earth's deep interior.”

Dr. Kate Rychert and Dr. Nick Harmon, formerly of the University of Southampton, Professor Saskia Goes from Imperial College London, and Professor Andreas Reitbrock from Karlsruhe Institute of Technology, led the experiment. The experiment was funded by NERC (Natural Environment Research Council, UK) and the ERC (European Research Council).

 

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About Woods Hole Oceanographic Institution

Woods Hole Oceanographic Institution (WHOI) is a private, non-profit organization on Cape Cod, Massachusetts, dedicated to marine research, engineering, and higher education. Established in 1930, its mission is to understand the ocean and its interactions with the Earth as a whole, and to communicate an understanding of the ocean’s role in the changing global environment. WHOI’s pioneering discoveries stem from an ideal combination of science and engineering—one that has made it one of the most trusted and technically advanced leaders in fundamental and applied ocean research and exploration anywhere. WHOI is known for its multidisciplinary approach, superior ship operations, and unparalleled deep-sea robotics capabilities. We play a leading role in ocean observation and operate the most extensive suite of ocean data-gathering platforms in the world. Top scientists, engineers, and students collaborate on more than 800 concurrent projects worldwide—both above and below the waves—pushing the boundaries of knowledge to inform people and policies for a healthier planet. Learn more at whoi.edu.

  

The James Cook Royal Research Vessel was used to deploy and recover the ocean bottom seismometers.

Credit

(Credit: Stephen Hick, U. College London)

Journal

Nature

DOI

10.1038/s41586-025-08754-0 

Method of Research

Imaging analysis

Subject of Research

Not applicable

Article Title

Seismic imaging of a basaltic Lesser Antilles slab from ancient tectonics

Article Publication Date

9-Apr-2025

 

Prehistoric rhinos lived in super-herds

Volcanic eruption 12 million years ago captures snapshot of extinct animals

University of Cincinnati

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Rhinos that flourished across much of North America 12 million years ago gathered in huge herds, according to a new study by the University of Cincinnati.

Researchers studied the isotopes of rhino teeth found in what is now northeast Nebraska. Here, more than 100 rhinos at a single water hole died and were entombed in ash from an eruption of the Yellowstone supervolcano.

Since the discovery of rhinos at Nebraska’s Ashfall Fossil Beds State Historical Park in 1971, researchers have wondered what drew so many animals together in the same place. Did they converge from far away, perhaps to seek shelter from the unfolding natural disaster of the volcanic eruption with its choking ash?

“We found they didn’t move very much,” lead author and UC graduate Clark Ward said. “We didn’t find evidence for seasonal migration or any evidence of a response to the disaster.”

The study was published in the Nature journal Scientific Reports.

Ward, who is now pursuing a doctorate at the University of Minnesota, used isotopic analysis of Miocene rhinos as part of a master's research project under the guidance of advisers and study co-authors Brooke Crowley at UC and University of Nebraska Professor Ross Secord.

Researchers examined ratios of isotopes of strontium, oxygen and carbon in fossil teeth to track the movements of the long-extinct animals across landscapes. Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons.

Grass or leaves that rhinos and other animals eat contain similar ratios of isotopes as the soil and bedrock where plants grow that allow researchers to determine where the animals fed, sometimes with surprising precision depending on how variable the vegetation and geology are.

Scientists use this technique in wildlife conservation. For example, they can track the migrations of wide-ranging animals such as caribou or identify the habitat needs of elusive animals like jaguars.

“By studying carbon in the animal, we can reconstruct carbon in the environment to understand what kinds of vegetation lived there,” Ward said.

Meanwhile, oxygen tells scientists about climate, particularly rainfall. 

“We can use it to reconstruct how wet or dry the environment was,” Ward said. “And strontium tells us where the animal was foraging because the ratio of isotopes is related to the soil and supporting bedrock.”

Teleoceras major was a one-horned rhino with a barrel-shaped body and stubby legs like a hippo. Like hippos, they fed on grass. And like hippos, researchers think these rhinos spent a lot of time in and around water. Because of their vast size, they had few predators in the Miocene epoch, Ward said.

But their calves would have been vulnerable to hyena-like predators called bone-crushing dogs. Indeed, some of the specimens found at the Nebraska site bear evidence that scavengers removed portions of their carcasses after they died. And ancient tracks from the 100-pound dogs have been found there.

Yellowstone’s enormous volcano has erupted many times over the past 12 million years. Ash from the eruption easily would have traveled 700 miles across what is now Nebraska where it piled up like snow nearly a foot deep in places. But windblown ash continued to fall on Nebraska long after the initial eruption, Ward said.

“That ash would have covered everything: the grass, leaves and water,” Ward said. “The rhinos likely weren’t killed immediately like the people of Pompeii. Instead, it was much slower. They were breathing in the ash. And they likely starved to death.”

Rhino expert John Payne spent his career working with endangered Sumatran rhinos in Malaysia. Payne, who was not part of the study, said UC’s research addresses scientific debate about the social structure of this ancient species of rhino.

“I am not surprised that the analyses very strongly suggest that Teleoceras major lived in herds given that this animal resembles modern hippopotamus in form and hippos live in herds of several tens of animals — with several herds in one geographical area,” he said.

Ward worked as an intern at the place he loved as a child, Ashfall Fossil Beds State Historical Park, answering visitors’ questions about the fossils and participating in fossil excavations and preparation at the site.

“I’m honored and privileged to have my name in science attached to the site,” Ward said. “As someone who used to go to Ashfall as a kid, it’s come full circle.”

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Journal

Scientific Reports

DOI

10.1038/s41598-025-94263-z 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Enamel carbon, oxygen, and strontium isotopes reveal limited mobility in an extinct rhinoceros at Ashfall Fossil Beds, Nebraska, USA

Article Publication Date

9-Apr-2025

 

Children born in lower-opportunity neighborhoods may face higher incidence rates of asthma with recurrent exacerbations, NIH study finds

Environmental influences on Child Health Outcomes

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NIH Environmental influences on Child Health Outcomes

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Credit: Environmental influences on Child Health Outcomes

Children born in neighborhoods with fewer opportunities are more likely to experience repeated asthma flares requiring emergency care or medical treatment, with non-Hispanic Black children having the highest incidence rates of asthma with recurrent exacerbations, according to a new study funded by the Environmental influences on Child Health Outcomes (ECHO) Program at the National Institutes of Health.

Asthma with recurring exacerbations (AREs) is a more severe form of childhood asthma linked to worsened health, high medical costs, and significant challenges for both the patient and their family, especially compared to well-controlled asthma. ARE affects many children in the U.S., with about 6 and a half cases per 1,000 children per year in the nationwide ECHO program.

Neighborhood factors—such as access to housing, healthy food, transportation, and education—can impact childhood asthma development. The Child Opportunity Index (COI) is one measure used to assess these conditions, connecting residential addresses at different early-life stages to data on neighborhood resources. This index combines information from 29 factors, such as access to good schools, healthy food, parks, clean air, and job opportunities. Studies have shown that neighborhoods with higher COI scores tend to have better conditions that help children grow up healthier and have more opportunities for economic success.

ECHO researchers used the COI to analyze how these factors influenced the development of this severe type of childhood asthma. The study included data from 15,877 children born between 1990 and 2018 across 60 ECHO study sites in the U.S.

“This study suggests that individual- and neighborhood-level exposures may affect the risk for developing childhood ARE,” said Rachel Miller, MD, of the Icahn School of Medicine at
Mount Sinai.

Researchers found that:

• Children from low-opportunity neighborhoods had significantly higher incidence rates of asthma with recurrent exacerbations (ARE) than those from higher-opportunity areas.
• Non-Hispanic Black children had the higher rates across all neighborhood categories when compared to non-Hispanic White children.
• Among children in very low-opportunity neighborhoods, non-Hispanic Black and Hispanic Black children had rates of ARE several times higher than non-Hispanic White children.
• Young children (ages 2 to 4) and those with a parent who had asthma had a higher risk of ARE.

What happened during the study

In this study, researchers followed children from ages 2 to at least 5, and up to age 19. They collected information on asthma diagnoses and the use of corticosteroids, a medication that helps reduce inflammation in the body. ARE was identified if a child used corticosteroids at least twice during the follow-up period while being monitored by ECHO researchers.

The study also examined the link between COI scores and children's birth addresses. Researchers analyzed how neighborhood conditions influenced the development of asthma with recurrent exacerbations while accounting for individual health history and other factors.

“This study adds to the mounting evidence that investing in neighborhood resources may have a myriad of respiratory health benefits for children,” said Dr. Miller.   

Additional studies could help researchers further understand the prenatal and early childhood determinants of ARE at both the individual and neighborhood levels.

This collaborative research was published in the Journal of Allergy and Clinical Immunology.

About ECHO
The ECHO Cohort Consortium is a research program supported by the National Institutes of Health (NIH) with the mission to enhance the health of children for generations to come. ECHO Cohort investigators study the effects of a broad range of early environmental influences on child health and development. For more information, visit echochildren.org.

Miller, R. and Johnson, C. Child Opportunity Index at Birth and Asthma with Recurrent Exacerbations in the U.S. ECHO Program. Journal of Allergy and Clinical Immunology, DOI: 10.1016/j.jaci.2025.02.036

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Journal

Journal of Allergy and Clinical Immunology

DOI

10.1016/j.jaci.2025.02.036 

Method of Research

Observational study

Subject of Research

People

Article Title

Child Opportunity Index at Birth and Asthma with Recurrent Exacerbations in the U.S. ECHO Program

 

US Hospitals enhance care for babies exposed to substances in womb

American Academy of Pediatrics funds eight hospitals for learning collaborative

University of Oklahoma

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Benazir Drabu, M.D., associate professor of pediatrics at the University of Oklahoma College of Medicine, is a neonatal hospitalist at Oklahoma Children's Hospital OU Health.

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Credit: University of Oklahoma

OKLAHOMA CITY – In years past, health care providers took a punitive stance toward women giving birth to babies exposed to substances like opioids in the womb. Today, backed by research showing better outcomes through an educational, compassionate approach, providers at Oklahoma Children’s Hospital OU Health have created a process for surrounding mom and baby with the care they need in the hospital, at home and in their communities for the years to come.

The American Academy of Pediatrics granted funding to the University of Oklahoma for hospital providers to refine and improve the discharge process for mothers and babies with neonatal abstinence syndrome, also known as neonatal opioid withdrawal syndrome. The project, called the Perinatal Health and Substance Use Quality Improvement Virtual Learning Collaborative, is helping establish best practices for this transition. Oklahoma Children’s Hospital is one of eight hospitals nationwide chosen for the program.

Babies born with neonatal abstinence syndrome may experience withdrawal from the drugs that crossed the placenta while in utero. Symptoms include jitteriness, trouble sleeping, diarrhea, vomiting, poor appetite and, in severe cases, seizures. If symptoms can be managed in the Mother-Baby Unit, the health care team focuses on soothing techniques, feeding and sleep support. If a higher level of care is required, including medications, the baby is transferred to the Neonatal Intensive Care Unit. Once discharge is possible, it is essential to have a well-structured plan to ensure caregivers receive adequate guidance and support.

“We want to provide continuity of care for mom and baby,” said neonatal hospitalist Benazir Drabu, M.D., associate professor of pediatrics at the OU College of Medicine and team leader for the project. “Care starts prenatally and goes through labor and delivery, and for this project, we are focusing on our discharge planning. This is work we are already doing, but participating in the collaborative will allow us to learn how to do it better.”

Mothers and babies affected by substance use usually stay in the hospital longer than the general population of birthing mothers. When discharge approaches, an interdisciplinary team of physicians, nurses, social services providers, physical therapists and occupational therapists shifts its focus to keeping the family well-supported at home.

Soothing strategies used in the hospital are reinforced, including providing the family with a “sleep sack” that swaddles the baby and teaching them how to console a fussy baby. Safe sleep at home is also emphasized. The team encourages caregivers to have a crib or “pack and play” instead of letting babies sleep with parents.

“In many cases, families don’t have a separate place for the baby to sleep, so they put them in their own bed, which puts the baby at risk for an adverse event,” said neonatologist Patricia Williams, M.D., associate professor of pediatrics at the OU College of Medicine and a co-leader of the project.

Mothers are screened for depression and coached on successful breastfeeding. The hospital team also aims to strengthen communication with primary care providers to ensure continuity of care. Social service providers connect the family to community organizations, such as Sooner Start and Oklahoma Family Network, that provide everything from diapers to respite care to support groups.

In addition, families are referred to the Little STAR clinic for an appointment 30 to 90 days after hospital discharge. Little STAR is a follow-up program to the Substance Use Treatment and Recovery (STAR) prenatal clinic at OU Health.

“Studies have shown that babies who have prenatal substance exposure can have poor developmental outcomes, both cognitively and behaviorally,” said developmental and behavioral pediatrician Susan Redwine, M.D., an assistant professor of pediatrics in the OU College of Medicine and co-leader of the project. “We want to prepare caregivers for that but also give them hope because there are clinics and programs that can help. Early intervention is so important, as is being non-judgmental. Our goal is to provide as much support as possible.”

When babies reach 1 year old, they qualify for services at OU’s Child Study Center, which continues developmental and behavioral support up to age 7. “We want to be the bridge between the baby leaving the hospital and getting families into programs at the Child Study Center,” Redwine said.

OU was previously part of a national effort to improve the care of babies exposed to substances in the womb with its participation in the “Eat, Sleep, Console” clinical trial funded by the National Institutes of Health. The trial evaluated the “ESC” approach to caring for babies with neonatal abstinence syndrome. ESC includes feeding babies every three hours around the clock to address the weight loss that often comes with substance exposure. ESC also prioritizes consoling and ensuring babies get adequate sleep. If a baby cannot be consoled within 10 minutes, medication may be considered. The trial had good outcomes, including a shorter hospital stay and decreasing the likelihood the baby would need medication. ESC has now become the standard of practice.

“It gives us a sense of fulfillment to help these babies and their caregivers and to keep them together as much as possible,” Drabu said. “Sending them home happy and prepared is priceless.”

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About the University of Oklahoma

Founded in 1890, the University of Oklahoma is a public research university with campuses in Norman, Oklahoma City and Tulsa. As the state’s flagship university, OU serves the educational, cultural, economic and health care needs of the state, region and nation. In Oklahoma City, OU Health Sciences is one of the nation’s few academic health centers with seven health profession colleges located on the same campus. OU Health Sciences serves approximately 4,000 students in more than 70 undergraduate and graduate degree programs spanning Oklahoma City and Tulsa and is the leading research institution in Oklahoma. For more information about OU Health Sciences, visit www.ouhsc.edu.

 

Conceptualizing psychological contract theory in the context of digital labor platforms, app workers, gig economy

Authors propose expanding theory to include algorithms

Carnegie Mellon University

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Psychological contracts are the beliefs, perceptions, and informal obligations between an employer and an employee. Such contracts have long been conceived of as targeting a person, but with the emergence of algorithmic-enabled forms of employment in a gig economy, that is changing. Digital labor platforms act as technological intermediaries that connect customers with service-providing, independent freelancers on demand to carry out short-term tasks.

In this context, in a new article, researchers explored whether a worker can create a psychological contract with a non-human agent in the form of an algorithm that mediates their relationship with an organization. The article, by researchers at Carnegie Mellon University, the University College of Cork, and the University of Limerick, appears in Human Resource Management Journal.

“Addressing how psychological contracts emerge and the cognitive processes they activate among app workers is fundamental to understanding digitalized working relationships,” explains Denise M. Rousseau, professor of organizational behavior and public policy at Carnegie Mellon’s Heinz College, who coauthored the article. “The implications of this question compel a fresh look at the features of psychological contract theory and its assumptions.”

In their conceptual review, the authors propose expanding psychological contract theory to include a party that has until now been omitted: non-human agents in the form of an algorithm. In their work, they analyzed research on gig working relationships, where the idea of a worker-algorithm psychological contract is most pertinent.

Specifically, they focused on two basic questions: How does a psychological contract with the target party emerge? And why does a worker develop such a contract with the target party? Their article also draws on scholarship related to theory of mind, which sheds light on the innate capacities people have to understand their actions and those of other parties with respect to beliefs, goals, desires, and intentions.

The authors also explored how likely it is that app workers form a psychological contract with the algorithm itself. People tend to anthropomorphize entities with which they interact, from their pets to the cars they drive. Based on this tendency, the authors suggest that theory of mind can form on the part of a worker, who then attributes human qualities (e.g., thoughts, motives) to the algorithm that governs their employment arrangements. When workers conceive of the other party as having thoughts or motives, it can expand the array of resources they exchange, adding to the employment arrangement such socioemotional resources as respect and loyalty.

Although algorithmically mediated employment exchanges are new, psychological contract theory can help chart a path toward understanding an array of employment relationships beyond the conventional individual‐employer set-up, the authors suggest.

“When individuals provide services to customers through the mediation of a digital platform, a new party enters the work arrangement: the algorithm that governs the exchange and is shaped by those who contribute to its functioning,” says Ultan Sherman, senior lecturer in organizational behavior and human resource management at the University College Cork’s Cork University Business School, who coauthored the article.

“Understanding how workers make sense of their relationship with an algorithm and the likely expectations and demands they make of this new organizational party can help human resources function better predict workers' behavior over time.”

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Journal

Human Resource Management Journal

DOI

10.1111/1748-8583.12599 

Article Title

Anthropomorphising the Algorithm: A ‘Theory of Mind’ Perspective on Psychological Contract Creation in Gig Work Arrangements