Feed aggregator

Researchers at the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) have, for the first time, been able to record a debris flow over a distance of two kilometers at the Illgraben (VS). The study reveals where and how waves form within the flow and what happens when they pass over check dams.

Publication date: 1 June 2026

Source: Advances in Space Research, Volume 77, Issue 11

Author(s): Zhaowei Yu, Wanchun Chen, Wenbin Yu, Shilei Zhao

Publication date: 1 June 2026

Source: Advances in Space Research, Volume 77, Issue 11

Author(s): Zeyu Bao, Yi Deng, Weipeng Li, Yangyang Cui

Publication date: 1 June 2026

Source: Advances in Space Research, Volume 77, Issue 11

Author(s): Keke Shi, Xingchen Liu, Yining Zhi, Chuang Liu

Publication date: 1 June 2026

Source: Advances in Space Research, Volume 77, Issue 11

Author(s): Xiaoyi Wang, Zhaoyue Chen

Publication date: 1 June 2026

Source: Advances in Space Research, Volume 77, Issue 11

Author(s): Tianji Chen, Xue Bai, Shuaibing Deng, Dongying Ma, Haoze Chen, Shuiyuan Wu

Publication date: 1 June 2026

Source: Advances in Space Research, Volume 77, Issue 11

Author(s): Peilin Li, Chengyuan Liu, Guodong Xu

Publication date: 1 June 2026

Source: Advances in Space Research, Volume 77, Issue 11

Author(s): Tianji Chen, Jun Jiang, Xiaoyi Wang

Publication date: 1 June 2026

Source: Advances in Space Research, Volume 77, Issue 11

Author(s): Jiahao Qin, Hongxia Wang, Xudong Gao, Qian Wang, Jun Jiang

Mangrove forests, once considered one of the world's most threatened coastal ecosystems, are showing signs of recovery worldwide, according to new research from Tulane University that finds decades of losses largely offset by regrowth and expansion.

Ozone pollution has worsened in much of the continental United States over the past decade, fueled by wildfires and the long-distance transport of unhealthy air, according to a new study titled "Fires reverse progress toward ozone air quality standards in the U.S.," led by University of Iowa researchers and published in the journal Science.

Arctic communities are increasingly exposed to dangerous weather events due to climate change and rely on accurate weather forecasts. However, conditions in the lower atmosphere remain poorly observed in the Arctic because monitoring systems are expensive and difficult to deploy.

For the first time, mighty ocean waves generated in the Southern Ocean have been accurately measured all the way to the tiny ripples they form on the shores of Alaska. Professor Ian Young, from the University of Melbourne's Department of Infrastructure Engineering, is lead author on a landmark study that analyzed data from 300 drifting ocean buoys to gain a detailed understanding of how storms in Antarctica drive waves all around the globe.

Deep below the Tyrrhenian Sea offshore Italy, scientists drilled into what they thought would be dark mantle rock—and found pieces of granite that seemingly had no business being there. Those unexpected intrusions turned out to offer a rare glimpse of how a massive fault rapidly pulled deep Earth rocks toward the surface during the opening of a young ocean basin.

Earth is divided into two halves: the Northern and Southern Hemispheres. Both reflect equal amounts of sunlight (albedo) even though they have different landmasses and weather patterns, especially cloud distribution. Why this is so is an ongoing mystery waiting to be solved.

You may have heard the rumors of a "monster El Niño." It's not the first time we've heard forecasts like this in Australia, but this time, they aren't coming out of nowhere. Early signs in the Pacific have been building for months and forecasts now point to a high likelihood of a moderate to strong El Niño developing in 2026.

After centuries of overharvesting and environmental degradation reduced the world’s oyster reefs by 85%, restoration is bringing the conglomerations of thick-shelled mollusks back to coastal waters. And their return may have more benefits than scientists realized, new research suggests.

“Oysters build the foundation of an entire ecosystem.”

Oysters were initially restored to boost depleted fisheries, according to Rachel Smith, a marine ecologist at the University of California, Santa Barbara. As oysters cement their shells together into reefs, they create habitats for myriad species, including fish. “Oysters build the foundation of an entire ecosystem,” Smith said.

These days, oyster reefs are restored for reasons extending beyond ecology, including to rid coastal water of excess nutrients such as nitrogen. This pollutant enters coastal waters when wastewater, sewage, and fertilizer wash into the sea.

Past studies of nitrogen removed by oyster reefs largely looked at denitrification, a process in which microbes transform organic nitrogen in dead oysters and their excrement into inert gas. If organic nitrogen evades these microbes, it can be buried in reefs, but measurements of this mechanism are few.

Researchers collected cores from 20 oyster reefs in coastal North Carolina. Credit: Antonio Rodriguez/Institute of Marine Sciences, UNC-Chapel Hill

“[Burial] is definitely much less explored,” said Smith.

A study published in PLoS One looked beyond denitrification and found significant amounts of nitrogen become sequestered within oyster reefs as they grow, offering evidence that restored oyster reefs actually remove far more nitrogen than we thought.

Before she started this research, Anne Margaret Smiley, lead author of the new paper and a biogeochemist at the University of North Carolina (UNC) at Chapel Hill, suspected that the amount of nitrogen buried in oyster reefs would be small because organisms at the surface transform so much of it, leaving little left to bury. She was pleasantly surprised by the results.

“We’ve been looking at denitrification all this time, and now we found out that [oysters themselves] are really good at doing this too,” she said. “What an amazing thing to know.”

In Search of Buried Nitrogen

To explore how nitrogen is buried over time, scientists turned to 20 oyster reefs in the Rachel Carson National Estuarine Research Reserve near Beaufort, N.C., that were restored nearly 3 decades ago by UNC scientists.

Using a jackhammer and metal pipe, they extracted cores from the oyster reefs in 2011. About 10 centimeters in diameter, the cores sampled the full thickness of each reef, which ranged from 10 to 55 centimeters. Shortly after they were collected, the cores were sectioned off into 5-centimeter increments, sealed, and stored in a walk-in freezer. In the years since, the samples have proved useful for studying oyster reef growth during sea level rise and how much carbon the reefs sequester and in other areas of research. Recently, Smiley measured the nitrogen levels in each of these 5-centimeter sections.

Below the top 10 centimeters or so, where microbes break down organic matter, nitrogen levels increased. Looking at all samples, Smiley found that on average, a square meter of reef buried more than 6 grams of nitrogen each year, which is similar to the rate of nitrogen transformed by denitrification at oyster reefs.

“The more they can build up and out, the more [nitrogen] they can bury underneath.”

However, there was a large range in the amount of nitrogen buried, between 1 and 15 grams of nitrogen per square meter. The variability, the researchers found, was related to where the different oyster reefs grew.

For oyster reefs in sand flats, those in intertidal areas (between high and low tide on a shore) buried more than twice as much nitrogen as subtidal reefs, on average. Intertidal reefs grow faster and so bury more nitrogen. “The more they can build up and out, the more [nitrogen] they can bury underneath,” said Smiley.

But intertidal reefs that fringed the edge of salt marshes buried less nitrogen than other intertidal reefs. “They’re not able to grow as quickly,” she said, speculating that sediment from the neighboring marshes may slow reef growth.

Put Your Money Where Your Mollusk Is Intertidal oyster reefs, like this one in coastal North Carolina, are exposed above water at low tide. Credit: Johanna Rosman/Institute of Marine Sciences, UNC-Chapel Hill

North Carolina’s Department of Environmental Quality places the economic value of each kilogram of nitrogen removed from the environment at $26.39 (in 2024 dollars, which is about $28.50 in 2026). Using this figure, Smiley and her colleagues calculated that nitrogen removed from coastal waters and buried each year by a hectare of oyster reef has a value of $1,700 on average. This finding increases previous estimates of the value of oysters’ nitrogen removal services by 25% to 42%.

“A really valuable part of the study is not just taking those measurements, but then also translating that into valuation,” said Smith, who was not involved with the new study. The value of nitrogen burial can be added to oyster reef ecosystem services—the monetary value of benefits that humans gain from oyster reefs, such as clean water, food, and flood control. “[Buried nitrogen] is definitely an ecosystem service that I think is underappreciated,” she said.

Looking more broadly at the county that is home to the Rachel Carson Reserve, Smiley and her colleagues found that all the oyster reefs countywide bury about 120,000 kilograms of nitrogen each year—more than $3 million of value in the county’s shallow sounds and bays.

—Lisa S. Gardiner (@lisasgardiner.bsky.social), Science Writer

Citation: Gardiner, L. S. (2026), Oysters clean up more nitrogen pollution than we thought, Eos, 107, https://doi.org/10.1029/2026EO260182. Published on 4 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.

Editors’ Vox is a blog from AGU’s Publications Department.

Mesoscale and submesoscale ocean processes influence ocean circulation, air-sea fluxes, ecosystem variability, and transport of materials. A new article in Reviews of Geophysics examines how these fine-scale processes shape the Indian Ocean, an ocean basin with unique monsoon behavior and a disproportionate impact on global climate. Here, we asked the authors to explain what mesoscale and submesoscale processes are, the techniques and challenges of observing and modeling fine-scale processes, and how biogeochemical cycles and climate change interact with these processes.

In simple terms, what are mesoscale and submesoscale processes?

Mesoscale processes pertain to oceanic features such as eddies and fronts, which
typically span a range of approximately 10 to 100 kilometers and can persist from
weeks to months. Submesoscale processes are of an even smaller scale, ranging
between approximately 100 meters and 10 kilometers, and evolve rapidly within a time frame of hours to days. These encompass sharp fronts, filaments, and small vortices.

Mesoscale processes account for more than 80% of the total kinetic energy. Submesoscale motions are of particular significance as they generate robust vertical movements that establish a connection between the surface ocean and deeper layers. As elaborated in our review, mesoscale and submesoscale processes function as a crucial link between large-scale ocean circulation and small-scale turbulence, facilitating the transfer of energy across different scales and regulating the distribution of heat, salt, and nutrients throughout the ocean.

Why is it important to understand how fine-scale processes operate in the Indian Ocean?

The Indian Ocean has a disproportionate influence on global climate.

The Indian Ocean has a disproportionate influence on global climate. It absorbs over a quarter of the ocean’s net heat gain and directly affects the environment and food security of nearly one-third of the world’s population. Unlike other ocean basins, the Indian Ocean is uniquely shaped by seasonally reversing monsoon winds and is strongly coupled with climate modes like the Indian Ocean Dipole and the Madden- Julian Oscillation. Mesoscale and submesoscale variability in this region modulates biogeochemical cycles, air-sea fluxes, and even large-scale energy balance. As our review highlights, understanding these fine-scale dynamics is essential for improving predictions of monsoon rainfall, tropical cyclone behavior, and long-term climate change.

How do scientists study mesoscale and submesoscale ocean processes?

Scientists employ a combination of field measurements, satellite observations, and numerical models, all of which were summarized in our review. In-situ observations serve as the foundation for mesoscale and submesoscale processes in the ocean. They encompass research cruises, moored arrays such as the RAMA network, Argo profiling floats, and autonomous platforms. The in-situ observations capture the three-dimensional structures and multiple variables during mesoscale and submesoscale processes.

Satellite altimetry has long been the principal tool for observing mesoscale eddies. However, the newly launched Surface Water and Ocean Topography (SWOT) mission is revolutionary, as it offers sea surface height measurements at an unprecedented resolution, enabling the direct observation of submesoscale features for the first time.

High-resolution regional models with grid spacings of a few kilometers or less enable researchers to simulate these processes and test dynamical theories under controlled conditions.

What are some of the challenges in observing and modeling these processes?

In our review paper, we tackled the challenges in observations by adhering to four principles, namely high-resolution (more observations in a relatively small region), synchrony (observations conducted at the same time), persistence (observations for a long time), and interdisciplinary (observations of multiple ocean properties). These principles are anticipated to offer valuable guidance for future observational endeavors to surmount the corresponding challenges.

Modeling also poses difficulties. Even state-of-the-art climate models are unable to explicitly resolve submesoscale processes. Consequently, their effects have to be approximated via parameterizations. The development of accurate parameterizations continues to be an active area of research. Moreover, as the model resolution improves, the widely employed hydrostatic approximation may lose its validity, necessitating more intricate non-hydrostatic formulations. Data assimilation for such rapidly evolving features presents a particularly arduous challenge.

How do fine-scale processes interact with biogeochemical cycles in the Indian Ocean?

Mesoscale and submesoscale motions exert a strong regulatory influence on biogeochemical cycling.

Mesoscale and submesoscale motions exert a strong regulatory influence on biogeochemical cycling through the control of nutrient supply to the sunlit upper ocean. Cyclonic eddies elevate nutrient-rich deep waters into the euphotic zone, thereby promoting phytoplankton blooms. In contrast, anticyclonic eddies typically suppress surface productivity by deepening the mixed layer.

In the Arabian Sea, eddies and filaments can contribute up to 70% of the nutrients that support the monsoon-driven biological bloom. These fine-scale dynamics also have an impact on carbon dioxide exchange; mesoscale variability accounts for approximately 40% of the CO₂ flux variability in the western Arabian Sea. Moreover, eddies modulate oxygen minimum zones in the Arabian Sea and Bay of Bengal, where low oxygen levels have a profound effect on marine ecosystems.

How is climate change expected to influence these fine-scale processes in the Indian Ocean?

With the continuous progression of climate change, alterations in upper-ocean stratification, propelled by warming and modified freshwater inputs, are anticipated to transform the conditions giving rise to fine-scale instabilities. High-resolution climate model simulations suggest that in a warming global scenario, the eddy-active region associated with the Agulhas Current system may shift westward and poleward. This shift is correlated with the intensification of Agulhas leakage, which refers to the transport of warm Indian Ocean water into the Atlantic. These changes could exert far-reaching effects on global ocean circulation.

Warming is augmenting the frequency and intensity of marine heatwaves in the Indian Ocean.

Moreover, warming is augmenting the frequency and intensity of marine heatwaves in the Indian Ocean. These heatwaves disrupt vertical mixing and nutrient supply, thereby having cascading impacts on biological productivity. Nevertheless, substantial uncertainties persist in quantifying these long-term responses.

In general, there are two-way interactions between climate change and fine-scale processes. Alterations in one component will induce changes in the other, and the former will be subject to feedback from the latter.

What are the remaining questions or knowledge gaps where additional research is needed?

Our review reveals several key priorities. In the short term, specialized multi-scale observational campaigns are acutely required, especially in regions with insufficient sampling, to capture the three-dimensional structure and rapid evolution of submesoscale features. Additionally, a more in-depth understanding is needed regarding how eddies interact with barrier layers—regions characterized by strong salinity stratification that are unique to the northern Indian Ocean—and how these interactions regulate air-sea fluxes and marine heatwaves.

Longer-term challenges encompass integrating fine-scale dynamics into climate models and refining submesoscale parameterizations. Emerging tools from artificial intelligence and machine learning hold potential for representing unresolved processes and enhancing data assimilation. Finally, considering the logistical and financial requirements of fine-scale ocean research, sustained international collaboration will be indispensable.

—Lei Zhou (zhoulei1588@sjtu.edu.cn, 0000-0002-0433-3991) Shanghai Jiao Tong University, China; Dongxiao Wang (dxwang@mail.sysu.edu.cn, 0000-0001-8778-2188) Sun Yat-Sen University School of Marine Sciences, South China Sea Institute of Oceanology, China; Lin Wang (wanglin58@mail.sysu.edu.cn, 0009-0003-1062-5207) Sun Yat-Sen University, China; and Chunhua Qiu (qiuchh3@mail.sysu.edu.cn, 0000-0001-9684-6067)  Sun Yat-sen University School of Marine Sciences, China

Editor’s Note: It is the policy of AGU Publications to invite the authors of articles published in Reviews of Geophysics to write a summary for Eos Editors’ Vox.

Citation: Zhou, L., D. Wang, L. Wang, and C. Qiu (2026), Small-scale Indian Ocean dynamics underpin marine ecology and climate, Eos, 107, https://doi.org/10.1029/2026EO265025. Published on 4 June 2026. This article does not represent the opinion of AGU, Eos, or any of its affiliates. It is solely the opinion of the author(s). 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.

SummaryMachine learning offers new opportunities for geophysical inverse problems, yet conventional regularized inversions of potential field data remain limited by global smoothing constraints and low structural resolution. We propose a locally adaptive, data-driven framework that combines synthetic Earth model generation and ensemble learning for joint gravity and magnetic interpretation. Training models are generated using geologically informed Voronoi-based geometries and planar structures, and a random forest classifier is trained on local statistical features of gravity and magnetic anomalies. The method yields geologically consistent subsurface models that reproduce observed anomaly characteristics without explicit regularization or iterative inversion. Compared with nonlinear Bayesian and traditional regularized inversions applied to the same dataset, the approach provides a substantial reduction in computational cost while preserving key structural features. The performance of the method is inherently linked to how representative the training ensemble is with respect to the target structure, and the results should be interpreted within this context. This framework demonstrates a practical and efficient alternative for potential field inversion using machine learning.

An international team of scientists has discovered that plants are not responding to global warming in the way researchers long assumed. Scientists have expected that ecosystems would keep pace with warming by raising the temperature at which photosynthesis works best.