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Arctic fjords are among the most efficient natural systems for absorbing and storing carbon long term. However, as the Arctic is warming about four times faster than the global average, fjord ecosystems are changing rapidly. Against this backdrop, understanding the biological processes that regulate carbon storage is becoming increasingly important. Yet the microbial mechanisms that control whether carbon is stored in sediments or returned to the environment are still not fully understood.

A new study published in Nature shows that rock weathering increasingly counteracts river CO2 emissions as permafrost degrades. The study was carried out by a collaborative team of researchers from Umeå University in Sweden and East China Normal University.

Scientists have discovered that the southern Andes Mountains don't rise slowly and steadily as previously thought. Instead, the range builds itself in short, powerful "pulses" every few million years.

With every work commute or grocery store run, a car’s tires wear down, causing tiny fragments of rubber to break away from the tire surface. That microscopic debris can be washed into streams, waterways, and estuaries when it rains.

“Driving a car or even riding in a bus is a bit like dragging an eraser across the planet, except the crumbs are microplastics. Toxic microplastics.”

“Driving a car or even riding in a bus is a bit like dragging an eraser across the planet, except the crumbs are microplastics. Toxic microplastics,” said Britta Baechler, director of ocean plastics research at the Ocean Conservancy.

Products like packaging materials and microbeads might come to mind long before tires when thinking of microplastics. But rubber hitting the road is actually a major contributor of marine plastic pollution, with some studies showing tire wear particles account for nearly half of the microplastics in terrestrial and aquatic systems. And tire fragments have only recently been classified as nano- and microplastic particles in various environmental studies, meaning the presence of these toxic, tiny particles has likely been underreported.

Tires contain a blend of natural and synthetic rubber as well as other chemicals, additives, and metals. As a tire breaks down and enters the environment, small slivers can make their way into the diets of fish and other marine life. Many studies tend to focus on particles or chemicals from unused tires rather than actual road-worn tire debris.

To better understand how tire particles affect aquatic ecosystems, researchers exposed a pair of estuarine species to a mixture of both weathered and pristine tire particles. By assessing how the study’s fish and shrimp consumed the tire particles and how both particles and the chemicals they release into the water affected the species’ growth and behavior, researchers aimed to capture the ecological risks of tire pollution under more realistic conditions. They published their findings in Environmental Pollution.

A Taste for Tires

In the environment, the tire particles that creatures interact with naturally vary in size. The smallest are often emitted directly into the air right as they’re generated. “You’re going to see higher [tire particle] contamination along roadsides, for example, and not just in waterways,” said Susanne Brander, an ecotoxicologist and courtesy faculty at Oregon State University and one of the study authors.

“These tire particles are small, they’re able to move, some are airborne, some are waterborne, and that’s how they become so pervasive.”

Rain washes those particles off road surfaces and into storm drains, which may lead to freshwater sources. “That’s where the cycle begins. These tire particles are small, they’re able to move, some are airborne, some are waterborne, and that’s how they become so pervasive,” said Baechler, who was not part of the study.

Tires are constructed with complex materials and contain thousands of potential toxins. 6PPD is one such ingredient. It is used to keep rubber from cracking but can be extremely toxic to salmon even in small concentrations.

Researchers used a standard mix of tire types that might be found driving along U.S. roads—14% from light trucks, 41% from passenger cars, and 45% from trucks and buses. They weathered the tire particles by suspending them in water with organic matter and then mechanically processing them with glass beads, shaking, and autoclaving. This broke them down into microparticles between 1 and 20 micrometers in diameter and nanoparticles less than 1 micrometer in diameter. Another portion of the samples was processed even further to isolate the chemical compounds released from the tire particles, representing the leachate.

Researchers exposed inland silverside fish (Menidia beryllina) and mysid shrimp (Americamysis bahia) in their early life stages to a range of tire particles and leachate concentrations to mimic varying levels of environmental contamination.

“We observed significantly higher ingestion rates in both species when they were exposed to weathered tire particles” compared to pristine particles, said lead author Clarissa Raguso, a marine scientist and postdoctoral fellow at Portland State University.

Britta Baechler, director of ocean plastics research at the Ocean Conservancy, collects tire particles from a road in Portland, Ore. Credit: Britta Baechler

Though neither fish nor shrimp experienced significant mortality, weathered tire particles reduced growth in both species, and it took lower amounts of tire particles for shrimp to be affected. The shrimp also ingested more tire particles overall, likely because of their bottom-feeding style.

“I was surprised by the species-specific responses,” Raguso said. “We expected weathered tire particles to consistently have the strongest effects across both species and all end points.”

Tire particles affected the behavior of both species, though the fish were more affected by pristine particles and shrimp were more affected by weathered ones.

“While we did see stronger effects on growth and ingestion in both species, the increase in behavioral alterations associated with weathering was only observed in [mysid shrimp], suggesting that vulnerability to tire pollution varies by species,” said Raguso.

Behavioral effects related to stress altered the animals’ neurological function—some exposures caused hyperactivity and reduced stress responses, whereas others led to decreased activity. In the wild, these behavioral shifts could make the creatures easier targets for predators or disrupt breeding and feeding. This change could lead to a cascade of effects on the food web.

“Mysid shrimp are a really important food item for critical species,” Brander said. “Gray whales, for example, eat millions of those types of organisms per day. The larger fish that we catch as seafood eat mysids. Even though we’re looking at these small larval fish and shrimp that humans don’t eat, they’re a pathway to get to what we do eat.”

Taming Tire Pollution

Though tires are a leading source of microplastic pollution, potential solutions to ensure that fewer particles end up in waterways are in the works. One possibility is to change tires’ chemical composition so they shed fewer harmful microparticles while in use. Other research is being conducted at Portland State University installing traps to catch tire particles in stormwater runoff before they enter marine environments. Another project aims to attach devices to vehicles that capture tire dust before it even hits the road.

“This study is important because it moves microplastics research closer to real-world conditions, the kind of particles that organisms are actually exposed to in nature,” Baechler said. “And understanding how those particles behave after weathering is really critical for assessing ecological risk and informing future prevention and mitigation strategies.”

—Rebecca Owen (@beccapox.bsky.social), Science Writer

Citation: Owen, R. (2026), What tires leave behind can become toxic fish food, Eos, 107, https://doi.org/10.1029/2026EO260197. Published on 17 June 2026. Text © 2026. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Climate change could push UK rivers to dangerous extremes and bring more frequent rapid swings between wet and dry conditions—a phenomenon known as hydroclimatic whiplash—according to research led by the University of East Anglia (UEA). Researchers analyzed almost 700 river catchments across the UK to project how river flows may change at 2° C and 4° C of global warming. The results reveal stark regional contrasts and growing challenges for communities and water managers trying to plan for flood and drought risk, particularly in areas that will increasingly experience both.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Solid Earth

The formation of continental crust is a major unresolved question in Earth science. Volcanic arcs, such as the Aleutian Islands of Alaska, are thought to be an important source of new continental crust, but modern arc crust is usually more iron- and magnesium-rich than average continental crust. There are few places on Earth where scientists can directly observe the possible transition from mafic arc crust to more silica-rich, continent-like crust while an arc is still active. The Andreanof segment of the Aleutian Arc offers a rare opportunity to study this process because it is an active, relatively intact oceanic arc, without major disruption from back-arc spreading, and it contains several volcanic centers that may record different stages or styles of crustal evolution.

Mark et al. [2026] use seismic waves to image the crust beneath this arc segment. Their results show that this arc crust is still distinct from average continental crust, suggesting that additional chemical or physical changes are needed before arc crust becomes more continent-like. At the same time, localized zones of slower seismic velocity beneath the Atka and Tanaga volcanoes may indicate hotter and/or more silica-rich material in the lower crust. These findings provide an important in-place snapshot of early continental crust formation, while highlighting that the transformation from volcanic arc to continent is complex and still incomplete.

Citation: Mark, H. F., Lizarralde, D., Shillington, D. J., Cortés-Rivas, V., & Behn, M. D. (2026). Along-strike seismic structure of the Andreanof Aleutian Arc segment and implications for the formation of continental crust. Journal of Geophysical Research: Solid Earth, 131, e2025JB033339. https://doi.org/10.1029/2025JB033339

—Lindsay L. Worthington, Associate Editor, JGR: Solid Earth

Text © 2026. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Marine heat waves (MHWs) are events characterized by prolonged warm coastal and ocean conditions with wide-ranging impacts on ecosystem health and associated industries. While research on MHWs has historically relied on surface-water data from satellite observations and buoy records, new research from the Batten School of Coastal & Marine Sciences & VIMS highlights the need to—quite literally—go deeper.

SummaryHuang et al. (2025) reported the detection of 67 teleseismic marsquakes identified by P and S wave arrivals. The authors used a deep learning phase picker trained on local earthquake data and applied it to narrow-bandpass filtered seismic data recorded by NASA’s InSight seismometer, making use of similarities between local earthquake and teleiseismic marsquake recordings when adjusting for sampling rate and S-P time scaling relations. We review all detections as similarly done for the Marsquake Service catalogue and other studies on this data set, using the complementary wind and pressure data recorded by InSight. As these auxiliary data were not recorded in the second half of the mission, we also infer wind contamination from bandwidths in the seismic data that contain wind-sensitive lander modes. Additionally, we analyse the signal polarisation to compare it with the expected characteristics of P and S waves and the background noise. Our review indicates that all 67 detections reported by the authors correspond to atmospheric noise. In most cases, the detections relate to the seismic signature of small wind bursts followed by larger wind bursts, onsets of which are interpreted as P and S waves by the authors. Further, we show that if these events were interpreted as genuine marsquakes, their inferred epicentral distance distribution would not match typical marsquake distances, while their magnitudes would make them the largest events of the catalogue. For future studies that deal with seismic event detection and interpretation from InSight, we recommend a careful consideration of the established event and noise signal markers described in this comment and in the literature to avoid misinterpretation of noise as event signals.

SummaryHigh-speed train (HST) signals offer an abundant and eco-friendly seismic source along the railway, but their application to full waveform inversion (FWI) presents unique challenges due to complex source characteristics and field constraints. We develop an HST-based elastic FWI framework that models the train as a distributed pier-force: a chain of time-delayed excitations applied continuously along deeply embedded bridge piers. This source mechanism generates predominantly S- and Rayleigh-wave energy, providing enhanced shallow subsurface illumination. The synthetic anomaly experiment demonstrates that the distributed pier-force enables superior multi-parameter reconstruction, particularly achieving higher density accuracy than the explosive and single-force sources. Additional sparse acquisition tests validate the robustness of the method under limited receiver coverage. The field data application successfully reconstructs subsurface layering through simultaneous source and parameter inversion, supporting the physical plausibility of the distributed source model. Overall, this study establishes the distributed pier-force as an effective and computationally efficient HST source for shallow subsurface characterisation, while also highlighting limitations under realistic field conditions.

Hot and dry conditions have become synonymous with the risk of extreme wildfires. But a new paper argues that such conditions are not, by themselves, sufficient for blazes, and most warm years do not result in the burning of exceptionally large areas.

An international team of researchers has found plants in the tropics absorb much less carbon dioxide than previous modeling had suggested, which has implications for ecosystem management.

Publication date: 15 June 2026

Source: Advances in Space Research, Volume 77, Issue 12

Author(s): Qiang Zhang, Bing Yu, Yanchao Gu, Lei Wang, Wen Luo, Caijun Luo

Publication date: 15 June 2026

Source: Advances in Space Research, Volume 77, Issue 12

Author(s): Manoj Kaushik, Lt. Col. Jarmal Singh, Rama Rao Nidamanuri

Publication date: 15 June 2026

Source: Advances in Space Research, Volume 77, Issue 12

Author(s): Ayhan Aydın, Sena Pacci, Orhan Dengiz

Publication date: 15 June 2026

Source: Advances in Space Research, Volume 77, Issue 12

Author(s): Chunhua Jiang, Rui Gao, Liang Chen, Huizhong Zhu, Min Li, Xiang Gao

Publication date: 15 June 2026

Source: Advances in Space Research, Volume 77, Issue 12

Author(s): Haojie Li, Qingzhi Zhao, Yibin Yao, Hong Liang, Zhaoliang Zeng, Hongwu Guo, Anbang Wu, Ming Liu, Jinchao Bai, Yuxing Zhao, Yongjie Ma, Jing Yang, Jiasong Tian, Qingyuan Guo, Zhaohui Xiong

Snowfall deep inside East Antarctica has increased in recent decades, and distant ocean temperature changes may be partly responsible. Using long-term climate data and observations from Dome Fuji station, researchers found that the increase in snowfall is strongly linked to atmospheric blocking patterns that carry moist air into inland Antarctica. These patterns are, in turn, influenced by sea surface temperature changes in the subtropical South Atlantic Ocean—highlighting important climate connections across vast distances.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Biogeosciences

The landscape takes up carbon (C) from the atmosphere and stores it in soils, mitigating atmospheric greenhouse gas concentrations and the impacts of climate change. Soil biogeochemistry models are the most widely used tools for predicting soil organic carbon (SOC) stocks, particularly in understudied regions that lack comprehensive observations. However, these models were developed based on the dominant processes controlling SOC in North Temperate systems and informed by their data.

von Fromm et al. [2026] test model “transferability” (i.e., the ability to apply the model across sites or regions) to Sub-Saharan Africa, evaluating how three commonly used soil biogeochemistry models predict SOC compare to observations. The authors find that the three models perform poorly even when parameterized with local observations, suggesting that model structure is missing important processes. Upon further evaluation, the authors attribute poor model performance to an overemphasis on net primary productivity and inadequate representation of organo-mineral interactions and exchangeable calcium as controls on SOC.

While this paper’s subject is Sub-Saharan Africa, it begs the question of model transferability to other under-studied regions, either due to lack of observational data or explicit model evaluation such as is presented in this paper. Soil organic carbon sequestration is thought to be one of the largest stocks of stored carbon in the biosphere, so quantifying current soil elemental budgets and predicting future changes requires models to perform well.

Citation: von Fromm, S. F., Rocci, K. S., Anuo, C. O., Asabere, S. B., Kanyiri, J., Kengdo, S. K., et al. (2026). Evaluating soil carbon models for sub-Saharan Africa: Revealing knowledge gaps in subtropical and tropical soil biogeochemistry. Journal of Geophysical Research: Biogeosciences, 131, e2026JG009726. https://doi.org/10.1029/2026JG009726

—Ceara Talbot, Associate Editor, JGR: Biogeosciences

Text © 2026. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

A chain of remote islands and underwater volcanoes between Alaska and Kamchatka has revealed a much older chapter in Earth's tectonic history than previously known. Along the Aleutian Arc, the Pacific Plate dives beneath the North American Plate, creating one of the most active and important plate boundaries on Earth. An international research team has now shown that this subduction zone began at least 56 million years ago, significantly earlier than previous models had assumed. The findings, published in Nature Communications, shed new light on a major reorganization of plate motions and may also help better understand ancient global climate change.

Most of the earthquakes we hear about are due to tectonic plates colliding or sliding past each other near plate boundaries. Yet researchers have detected some enigmatic earthquakes happening inside the more stable interiors of plates. Intermediate-depth earthquakes (IDEs), which occur around 70–300 kilometers (43–186 miles) below the surface, are especially puzzling because rocks at those depths are hot enough to flow more fluidly.