How mountains are shaped by far-away forces

Scientists from GFZ and colleagues observe and model a rare geological process called "same-dip double subduction"

GFZ Helmholtz-Zentrum für Geoforschung

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The picture shows the dramatic uplift of 4.3 m due to the strong 2024 earthquake on the Noto Peninsula, Japan. The coastline was lifted and rocks formerly submerged are exposed. 

 

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Credit: Dr. Luca Malatesta, GFZ

A team of geoscientists lead by Guido M. Gianni identified a subtle but powerful force driving mountain building and compression of the Earth’s crust in Japan and neighboring regions: The so-called "same-dip double subduction" (SDDS) in nearby oceanic trenches has effects reaching hundreds and thousands of kilometres away from the zone of subduction. Guido M. Gianni, from GFZ Helmholtz Centre for Geosciences, and his colleagues from GFZ and the University of Miami, report their findings in the journal Nature Geoscience.

Subduction zones, where tectonic plates dive beneath one another, are already known to be the source of the strongest and most devastating earthquakes as well as for volcanic arcs, and the movement of Earth’s crust. The new study reveals that when two nearby subduction zones dip in the same direction, as seen in the Ryukyu and Izu-Bonin-Marianas trenches to the south of Japan, the effect isn’t just local. The subduction zones also affect so-called backarc areas.

Backarc areas are part of the larger picture of plate tectonics: Where subduction occurs deep oceanic trenches form. “Behind” the trenches, as seen from the moving direction of the oceanic plate, mountains can form by deforming continental crust during subduction, and on top of the mountains, volcanoes form, often aligned like an arc. And behind that, hence the name, backarc regions emerge.

The researchers used advanced 3-D geodynamic modeling to show the effects of the SDDS system that has been dragging the Pacific trench westward over the past 10 million years. This motion puts stress on the overlying plate in Northeast Japan, initiating a wave of compression that doesn't stem from a direct plate collision. The resulting crustal squeezing has built up mountains in Northeast Japan and possibly even actively triggered a new subduction zone in the backarc Japan Sea area, including the region of the devastating 2024 Noto Peninsula earthquake.

The authors’ model of “double subduction-induced orogeny” improves long-held views on how non-collisional mountain building occurs. Their study highlights how distant plate interactions can shape regions up to thousands of kilometers away. “Our models show a significant increase in horizontal stress in the upper plate above the Pacific trench, mirroring the deformation belt of thrust faults along northeast Japan, earthquakes, and crustal deformation extending over 1,000 kilometers into Japan's backarc,” says first author Guido M. Gianni. He was working as an Alexander von Humboldt Research Fellow at GFZ’s section “Lithosphere Dynamics” at the time of the study. Guido M. Gianni comes from the National Scientific and Technical Research Council (CONICET), in Buenos Aires, Argentina.

Beyond modern Japan, the research suggests that similar SDDS mechanisms may explain ancient mountain-building events in places like the Mediterranean in the Mesozoic and South America in Paleozoic times. Guido M. Gianni says: “These insights not only refine our understanding of tectonic processes but also have implications for seismic hazard assessment in regions experiencing similar subduction interactions.”

Thus, the study offers a new way of thinking about how Earth's plates interact, and how those interactions can silently but powerfully reshape the surface of our planet.

Original study: Gianni, G.M., Guo, Z., Holt, A.F. et al. Non-collisional orogeny in northeast Japan driven by nearby same-dip double subduction. Nat. Geosci. 18, 525–533 (2025). https://doi.org/10.1038/s41561-025-01704-5

Scientific contact: Guido M. Gianni

guido.martin.gianni@gfz.de

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Journal

Nature Geoscience

DOI

10.1038/s41561-025-01704-5 

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

Non-collisional orogeny in northeast Japan driven by nearby same-dip double subduction

 

New study finds concerning sea star response to a neurotoxin

Bigelow Laboratory for Ocean Sciences

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Sea stars being held for an experiment in the advanced seawater suite at Bigelow Laboratory.

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Credit: Dennie Truong, Courtesy of Bigelow Laboratory

For the last several months, Southern California has grappled with a bloom of harmful algae that produce domoic acid, killing or intoxicating thousands of marine animals. But this region isn’t unique. Problematic outbreaks of DA, a naturally occurring amino acid that’s also a potent neurotoxin, are becoming increasingly common along both the West and East coasts.   

DA can enter the food web when it is consumed by filter feeders like mussels and then accumulates up in marine predators. When DA intoxicates “keystone” species, which play an outsized role in maintaining local biodiversity, it can have cascading consequences for all the animals around them.  

While the impacts of DA on marine vertebrates are well-documented, its effects on marine invertebrates — those without backbones — have received less attention. A new study in Diseases of Aquatic Organisms, led by researchers at Bigelow Laboratory for Ocean Sciences, fills this gap by examining whether DA accumulates in wild sea stars and if it has any behavioral or physiological impacts.

The team found potentially concerning concentrations of DA, particularly in smaller sea stars, even in the absence of the algal blooms that are thought to drive DA outbreaks. When experimentally exposing the animals to kainic acid, a structurally similar compound, the researchers also saw an immediate physical response. Though those behavioral changes appear to be reversible, the findings raise concerns about the potential consequences of repeated, long-term, or higher-level exposure on sea stars.

“Some species of sea stars are the keystone species of the intertidal zone, and we know if domoic acid is harming them, other animals down the line could be affected,” said the study’s lead author, Dennie Truong, a recent Colby College graduate and former Bigelow Laboratory intern. “There’s very little information out there on domoic acid in sea stars, so this was a critical first step to understanding the dynamics of DA intoxication.”

DA is produced by over 20 different species of single-celled algae in the genus Pseudo-nitzschia, and it can have significant health effects — including on humans that eat contaminated seafood. Despite the risk, and the ecological importance of sea stars, little work has been done to determine what concentration of DA is toxic to them.

“Sea stars aren’t a human food source or commercially valuable, but they’re fascinating biologically and vital ecologically,” said Research Scientist Reyn Yoshioka, a co-author on the paper. “Understanding how DA may be present in and affect diverse species is key to us holistically understanding the impacts of marine biotoxins.”

In 2022, while Truong was a participant in Bigelow Laboratory’s Sea Change Semester, he worked in the lab of Senior Research Scientist Maya Groner, with Yoshioka and former Research Associate Carmen Cartisano, to measure the concentrations of DA in sea stars from Strawberry Hill in Oregon and Lamoine State Park in Maine.

The researchers detected levels of DA in the sea stars similar to the known toxicity levels for other marine animals, despite there being no evidence of recent Pseudo-nitzschia blooms. They also found that the compound was most concentrated in the pyloric caeca, an organ that is critical to sea star digestion and energy storage.

The researchers then undertook experiments to better understand the potential effects of this exposure.

For seven days, they held sea stars in tanks in Bigelow Laboratory’s seawater suite, which continuously pumps in aerated seawater directly from the ocean. The sea stars were injected with kainic acid at different concentrations to reflect what they might experience in the wild.

For the animals in the “high dosage” group, the effects were almost immediate. “They just curled right up into a ball,” Truong said. The vast majority lost the ability to right themselves when flipped on their backs, and many had deflated arms.

These behavioral changes did eventually wear off — within a few days for righting time and a week for arm circumference. But the nature and immediacy of the reactions, the authors argue, are concerning. It suggests that kainic acid may be disrupting the mutable collagenous tissue, which is vital for sea star movement and structural integrity.

These findings, Truong said, provide the first evidence of how — and how much — DA affects sea stars, which is the first step to understanding its ecological consequences. In the future, the team wants to confirm that DA has the same experimental effect as kainic acid and dig into the relationship they observed between body size and DA accumulation, and what that might mean for different sea stars’ ability to handle toxins.

“We have seen substantial declines in sea stars in the past decade attributed to changes in mussel abundance and sea star wasting syndrome, but this work suggests that harmful algal blooms may also be a problem for them,” said Groner, the paper’s senior author. “As these harmful algal blooms that produce domoic acid become increasingly common, it’s important that we understand their impacts on keystone species, marine food webs, and biodiversity.”

Sea stars curling into tight balls in response to experimental injections of kainic acid.


Credit
Dennie Truong, Courtesy of Bigelow Laboratory





Algae from the genus Pseudo-nitzschia, some species of which are responsible for producing domoic acid.

Credit
Peter Countway, courtesy of Bigelow Laboratory




Dennie Truong, a recent Colby College graduate, participant in the Bigelow Laboratory Sea Change Semester program, and the study’s lead author.

Credit
Maya Groner, Courtesy of Bigelow Laboratory

Journal

Diseases of Aquatic Organisms

DOI

10.3354/dao03864 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Marine and synthetic glutamatergic neurotoxins accumulate in and immobilize intertidal sea stars

Article Publication Date

28-Aug-2025

 

Possible North Atlantic overturning circulation shutdown after 2100 in high-emission future

Potsdam Institute for Climate Impact Research (PIK)

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Under high-emission scenarios, the Atlantic Meridional Overturning Circulation (AMOC), a key system of ocean currents that also includes the Gulf Stream, could shut down after the year 2100. This is the conclusion of a new study, with contributions by the Potsdam Institute for Climate Impact Research (PIK). The shutdown would cut the ocean’s northward heat supply, causing summer drying and severe winter extremes in northwestern Europe and shifts in tropical rainfall belts. 

“Most climate projections stop at 2100. But some of the standard models of the IPCC – the Intergovernmental Panel on Climate Change – have now run centuries into the future and show very worrying results,” says Sybren Drijfhout from the Royal Netherlands Meteorological Institute, the lead author of the study published in Environmental Research Letters. “The deep overturning in the northern Atlantic slows drastically by 2100 and completely shuts off thereafter in all high-emission scenarios, and even in some intermediate and low-emission scenarios. That shows the shutdown risk is more serious than many people realise.”

 

Collapse of deep convection in winter as the tipping point 

 

The AMOC carries sun-warmed tropical water northward near the surface and sends colder, denser water back south at depth. This ocean “conveyor belt” helps keep Europe relatively mild and influences weather patterns worldwide. In the simulations, the tipping point that triggers the AMOC shutdown is a collapse of deep convection in winter in the Labrador, Irminger and Nordic Seas. Global heating reduces winter heat loss from the ocean, because the atmosphere is not cool enough. This starts to weaken the vertical mixing of ocean waters: The sea surface stays warmer and lighter, making it less prone to sinking and mixing with deeper waters. This weakens the AMOC, resulting in less warm, salty water flowing northward. 

 

In northern regions, then, surface waters become cooler and less saline, and this reduced salinity makes the surface water even lighter and less likely to sink. This creates a self-reinforcing feedback loop, triggered by atmospheric warming but perpetuated by weakened currents and water desalination.

“In the simulations, the tipping point in key North Atlantic seas typically occurs in the next few decades, which is very concerning,” says Stefan Rahmstorf, Head of PIK’s Earth System Analysis research department and co-author of the study. After the tipping point the shutdown of the AMOC becomes inevitable due to a self-amplifying feedback. The heat released by the far North Atlantic then drops to less than 20 percent of the present amount, in some models almost to zero, according to the study. 

 

Lead author Drijfhout adds that “recent observations in these deep convection regions already show a downward trend over the past five to ten years. It could be variability, but it is consistent with the models’ projections.”

It is crucial to cut emissions fast

To arrive at these results, the research team analysed CMIP6 (Coupled Model Intercomparison Project) simulations, which were used in the latest IPCC Assessment Report, with extended time horizons to years from 2300 to 2500. In all nine high-emission simulations, the models evolve into a weak, shallow circulation state with the deep overturning shutting down; this result is produced in some intermediate and low-emission simulations as well. In every case, this change follows a mid-century collapse of the deep convection in North Atlantic seas.

 

“A drastic weakening and shutdown of this ocean current system would have severe consequences worldwide,” PIK researcher Rahmstorf points out. “In the models, the currents fully wind down 50 to 100 years after the tipping point is breached. But this may well underestimate the risk: these standard models do not include the extra fresh water from ice loss in Greenland, which would likely push the system even further. This is why it is crucial to cut emissions fast. It would greatly reduce the risk of an AMOC shutdown, even though it is too late to eliminate it completely.”

Article:
Sybren Drijfhout, Joran R. Angevaare, Jennifer Mecking, René M. van Westen, Stefan Rahmstorf (2025): Shutdown of northern Atlantic overturning after 2100 following deep mixing collapse in CMIP6 projections. Environmental Research Letters. DOI [10.1088/1748-9326/adfa3b]

Weblink to the article: https://iopscience.iop.org/article/10.1088/1748-9326/adfa3b

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Journal

Environmental Research Letters

DOI

10.1088/1748-9326/adfa3b 

Method of Research

Computational simulation/modeling

Article Title

Shutdown of northern Atlantic overturning after 2100 following deep mixing collapse in CMIP6 projections.

Article Publication Date

28-Aug-2025

Strengthening climate action: Experts propose major reforms for the IPCC–UNFCCC relationship

Stockholm University

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Örjan Gustafsson, Stockholm University

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Credit: Stockholm University

A new paper on the science-policy interface by climate experts Svante Bodin and Örjan Gustafsson at the Bolin Centre for Climate Research, Stockholm University, calls for urgent reform to the relationship between the Intergovernmental Panel on Climate Change (IPCC) and the United Nations Framework Convention on Climate Change (UNFCCC).

The authors of the paper, published in Nature Climate Change, argue that the current structural divide between the intergovernmental bodies IPCC and UNFCCC – one focused on scientific assessment and the other on global climate policymaking – is hindering timely and effective climate action. The report outlines how the misalignment in timing, relevance, and communication between the IPCC’s scientific outputs and the UNFCCC’s policy needs limits the global response to the climate crisis.

The paper identifies systemic inefficiencies resulting from the absence of timely, policy-responsive scientific input into the UNFCCC negotiation process. The authors assert that despite the IPCC’s globally respected assessments, the lack of synchronization with the annual UNFCCC policy cycle and insufficient mechanisms for scientific uptake have constrained informed decision-making.

“Climate policy must be grounded in scientifically rigorous and immediately relevant information. Our proposals aim to strengthen the institutional interface while preserving the independence and integrity of both entities,” says Örjan Gustafsson, professor of biogeochemistry at the Department of Environmental Science and the Bolin Centre for Climate Research, Stockholm University.

“Between the two of us, we have spent a career each at the forefronts of climate science and climate policy, each noting the dysfunctional and ineffective relationship between the IPCC and the UNFCCC and wondering why nothing has happened over the decades to resolve and remedy the gaps and communication deficiencies,” says Svante Bodin, affiliated with the Bolin Centre for Climate Research and former head of Sweden’s delegations to IPCC, UNFCCC and other international agreements.  

Taking inspiration from more successful multilateral environmental agreements – such as the UN-ECE’s Convention on Long-Range Transboundary Air Pollution and the Montreal Protocol – the authors recommend a series of reforms designed to increase responsiveness, improve communication channels, and tailor scientific outputs to pressing policy needs. These include:

• Regular evaluations of UNFCCC’s evolving policy demands, formally conveyed to the IPCC
• Direct UNFCCC involvement in IPCC scoping processes through structured consultation mechanisms
• More frequent, thematically focused IPCC reporting aligned with negotiation timelines and subjects
• The establishment of a scientific advisory body within the UNFCCC to facilitate assessment uptake.

The authors urge immediate action from governments to align their IPCC and UNFCCC policies and highlight that these reforms can be implemented without altering the legal foundations of either entity.“This is not about merging institutions – it is unlocking their combined potential,” according to Örjan Gustafsson and Svante Bodin.

Article in Nature Climate Change: Improving the IPCC–UNFCCC relationship for effective provision of policy-relevant science

 

Novel therapy for pet cats with head and neck cancers could help humans, too

Cell Press

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Jak, a research partifipant, in April 2023, about six months after completion of the clinical trial.

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Credit: Tina Thomas

Researchers have reported results from the first-ever clinical trial of a new class of targeted therapy in pet cats with head and neck squamous cell carcinoma (HNSCC)—a cancer which is notoriously deadly and difficult to treat. Publishing in the Cell Press journal Cancer Cell on August 28, the study found that 35% of the cats who received treatment had their disease controlled with minimal side effects—and the drug will likely be effective for humans with HNSCC as well. 

“There are two major findings from this study,” says senior author Daniel Johnson of the University of California, San Francisco Helen Diller Family Comprehensive Cancer Center. “It showed us that it’s possible to target a transcription factor that drives oncogenesis, which is something that has been notoriously difficult in the past. Also, it demonstrated that pets with cancer can be a good representation of human disease and that clinical trials in pets may yield more reliable results than tests in mouse models.” 

This drug, which was initially conceptualized to treat human head and neck cancers, is the first to target the transcription factor STAT3. STAT3 is present in a range of both solid and liquid tumors, including a majority of HNSCC cases. 

The idea to test the HNSCC drug on pet cats came from a discussion first author Jennifer Grandis had with her sister, a veterinarian. Grandis learned that oral cancers like HNSCC in pet cats are extremely difficult to treat and that most animals die within 2 to 3 months of diagnosis.  

“There is remarkable clinical, histopathologic, and immunologic similarity between feline and human HNSCC,” the authors write. 

One cat who benefited from the trial was a 9-year-old black domestic shorthair named Jak. When he was diagnosed with HNSCC, the veterinarian gave him only 6 to 8 weeks to live.  

“It was just a gut punch,” says his owner, Tina Thomas. “We wanted more time with him. When I found out about this clinical trial, I knew I wanted him to be a part of it.” 

Jak went for weekly treatments for one month. During that time his symptoms—mainly, a watery eye—greatly improved. He ultimately lived more than 8 months after his diagnosis. 

“It was meaningful to us because he was here in our lives,” says Thomas. “During that time, my son finished college and my daughter finished her master’s program. Jak got to spend one more Christmas with us, and he loved our Christmas tree. He was worth every bit of the effort.” 

Other than mild anemia, none of the cats in the trial developed side effects that were attributable to the treatment. Of the 20 cats that were enrolled, 7 of them exhibited either a partial response or stable disease during the study period. Among the 7 that responded, the average survival post-treatment was 161 days. 

When the investigators looked at tumors and blood samples from the cats who underwent treatment, they saw that the compound was working in two ways: It not only blocked the activity of STAT3 but it also raised levels of PD-1, a protein associated with an immune response to cancer. 

“This study is a great example of how we can think more carefully about spending our very limited resources on studies in lab mice that are not even the best models of human cancers,” Grandis says. “By partnering with veterinary oncologists and doing clinical trials in companion animals, we can learn an enormous amount about how these drugs work while also helping people’s pets. None of the cats in these trials were harmed, and many of them benefited.” 

The researchers say that conducting clinical trials in pets can be a much better model of how drugs will work in humans compared with lab mice. They are currently working with a small biotech company to advance the new compound in clinical trials for both pets and humans. 

“These animals breathe the same air that we breathe and are exposed to all the things we’re exposed to,” says Johnson. “Their tumors are much more heterogeneous, which makes them a better mimic of human disease.”

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This work was supported by the National Institutes of Health and the Center for Companion Animal Health at the University of California Davis. 

Cancer Cell, Grandis et al., Safety and efficacy of a STAT3-targeted cyclic oligonucleotide: From murine models to a phase 1 clinical trial in pet cats with oral cancer” https://www.cell.com/cancer-cell/fulltext/S1535-6108(25)00321-6

Cancer Cell (@Cancer_Cell), published by Cell Press, is a monthly journal that provides a high-profile forum to promote major advances in cancer research and oncology. The journal covers topics related to molecular and cellular mechanisms of cancer, mechanisms for the sensitivity and the resistance to cancer therapies, development of better cancer therapies, and clinical investigations. Visit: http://www.cell.com/cancer-cell. To receive Cell Press media alerts, contact press@cell.com. 

Jak, a research participant, made it through another Christmas after the clinical trial, which was longer than his estimated time left after his diagnosis.



Jak, a research participant, during the clinical trial.

Jak, a research participant, laying in the sun.

Credit
Tina Thomas


Journal

Cancer Cell

DOI

10.1016/j.ccell.2025.07.015 

Method of Research

Randomized controlled/clinical trial

Subject of Research

Animals

Article Title

Safety and efficacy of a STAT3-targeted cyclic oligonucleotide: From murine models to a phase 1 clinical trial in pet cats with oral cancer

Article Publication Date

28-Aug-2025

FOR PROFIT HEALTHCARE U$A

Debt, bankruptcy, and credit scores after cancer diagnosis

JAMA Oncology

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About The Study: 

In this retrospective cohort study, modest amounts of medical debt in collections persisted for years after cancer diagnosis. Total debt in collections was present at higher amounts for certain cancer subpopulations. The persistence of adverse financial outcomes after cancer diagnosis, despite high rates of insurance coverage in Massachusetts, warrants further research and consideration of broader systemic reforms.

Corresponding Author: To contact the corresponding author, Benjamin C. James, MD, MS, email bjames1@bidmc.harvard.edu.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamaoncol.2025.3302)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

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 https://jamanetwork.com/journals/jamaoncology/fullarticle/10.1001/jamaoncol.2025.3302?guestAccessKey=b18be536-b3f3-4fdc-80d4-c8452f02fa3a&utm_source=for_the_media&utm_medium=referral&utm_campaign=ftm_links&utm_content=tfl&utm_term=082825

 

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Journal

JAMA Oncology