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A recent study led by Prof. Chen Yaning from the Xinjiang Institute of Ecology and Geography of the Chinese Academy of Sciences has found that climate warming is increasing flood risks from rain-on-snow (ROS) events in High Mountain Asia. The study, published in npj Climate and Atmospheric Science, analyzed the distribution, causes, and flood risks of ROS events.

Tropical cyclones are hurricanes that brew over the tropical ocean and can travel over land, inundating coastal regions. The most extreme cyclones can generate devastating storm tides—seawater that is heightened by the tides and swells onto land, causing catastrophic flood events in coastal regions.

Imagine if Earth's history had a mystery novel, and one of its biggest unsolved puzzles was: Where did all the nitrogen go? Scientists have long known that our planet's rocky outer layers—the mantle—are oddly poor in nitrogen compared to other volatile elements like carbon or water. Very strangely, the C/N and 36Ar/N ratios in the bulk silicate Earth (BSE, the whole Earth minus the metallic core) are far higher than those found in the meteorites that supposedly delivered these ingredients during the planet's infancy.

Research led by the Union of Concerned Scientists reports that emissions from the world's largest fossil fuel and cement companies have contributed significantly to both present-day and long-term sea level rise. Products from 122 major producers have contributed up to 37% of the rise in global sea level observed through 2022 and may account for an additional 0.26 to 0.55 meters by 2300.

Sustained scientific observations and monitoring are crucial for measuring ocean change, providing valuable data that contributes to a better understanding of oceanography, biodiversity, and the interconnectedness of global systems, and helps inform decisions about conservation and resource management.

What is the role of dissolved organic matter in the deep sea? In a study relating to this question, researchers from the Universities of Bremen and Oldenburg have investigated the composition of dissolved organic matter (DOM) in detail. Their samples were obtained during an expedition to the Guaymas Basin in the Gulf of California.

Nearly three-fourths of Earth is covered by oceans, making the planet look like a pale blue dot from space. But Japanese researchers have made a compelling case that Earth's oceans were once green, in a study published in Nature.

A warm cup of tea could offer some unexpected health benefits.

While steeping, tea leaves soak up lead ions from water, researchers reported in ACS Food Science and Technology. Though the process doesn’t completely purify the water and is not intended for large-scale water remediation, the passive benefit could help explain the correlation between regular tea consumption and lower incidences of heart disease and stroke.

“This idea that the tea bag, or tea within the bag, would absorb something was something nobody thought about.”

Tea is known to release various compounds such as tannins and caffeine into water. But “this idea that the tea bag, or tea within the bag, would absorb something was something nobody thought about,” said Vinayak Dravid, a coauthor of the study and a materials scientist at Northwestern University.

In the lab, Dravid and his research group regularly develop spongelike materials that absorb pollutants. The composition of one of these sponges reminded study coauthor Benjamin Shindel of tea bags, Dravid said. Shindel, at the time a Ph.D. candidate and now a materials scientist contracting with the U.S. Department of Energy, suspected that conditions inside a cup of tea would encourage metals to stick to the tea leaves.

To test the hypothesis, Shindel and his colleagues prepared solutions made of water with different concentrations of lead, ranging from 10 parts per billion—EPA’s trigger level for lead—to highly toxic levels of 10 parts per million. Then they heated the solutions to 85°C (185°F, just below the boiling point of water) and prepared different kinds of teas, including traditional black, green, oolong, and white teas brewed from the Camellia sinensis plant as well as the herbal teas rooibos and chamomile. After steeping the tea leaves for a range of times—anywhere from a few seconds to 4 hours—the researchers measured how much lead was left in each cup.

Spilling the Tea

Black and green teas were the most effective at removing lead, the team found, although the type of tea had less efficacy than the time it steeped. Finely grinding the leaves before steeping slightly improved their performance, likely because the increased surface area left more space for lead atoms to attach to the leaves. Steeping leaves in a cup of black tea for 5 minutes removed about 15% of the lead from the laboratory solutions. White and herbal teas, whose leaves remain smooth as they steep, were less effective.

The wrinkled surface of black tea leaves, seen here under a scanning electron microscope, may contribute to an increased surface area onto which lead and other metal ions adsorb. Credit: Vinayak P. Dravid Group/Northwestern University

The longer the leaves steeped, researchers found, the more lead adsorbed onto them. The longer leaves steep, however, the more bitter the tea becomes.

Tea’s metal-remediating benefits weren’t limited to lead. The team also prepared separate solutions of cadmium, chromium, copper, and zinc. Ions of each adsorbed onto the leaves.

In addition to the leaves themselves, the team also experimented with whether the type of tea bag influenced the amount of metal removed. Though nylon and cotton tea bags didn’t remove any lead, the metal did bind to cellulose (or “wood pulp”) tea bags.

Previous research has shown that C. sinensis can absorb metals from soil and store them in its leaves, so “there is always a risk, and obviously a concern, that you are actually then contributing those heavy elements and heavy toxins into water again when you make tea,” Dravid said.

But the new study suggests that metals will stick with the plant and not be released into the surrounding environment. “What our work showed,” Dravid explained, is that C. sinensis “has an affinity for heavy metals—that even if they exist in the leaf, they actually will remain. And that’s so reassuring.”

Brewing with Perspective

Tea leaves are not a substitute for existing methods of water purification, the authors emphasized. Most of the lead that enters drinking water does so through lead pipes connecting water mains and homes, and many domestic faucets or under-sink filters can remove more than 90% of lead ions.

Instead, tea leaves are “a way of reducing the lead exposure that occurs naturally,” explained Marc Edwards, an environmental engineer at Virginia Tech who was not involved in the study. Tea leaves could help mitigate—though not completely remove—the presence of other metals that enter drinking water either through corrosion (e.g., of copper or zinc pipes) or through erosion of mineral deposits like chromium.

“It’s not going to remove all the metal in the water.…But it is removing a fraction that may be meaningful from a public health perspective.”

“It’s not going to remove all the metal in the water, 99.9% or something like this,” Shindel agreed. “But it is removing a fraction that may be meaningful from a public health perspective.” If brewing tea removes 15% of lead and a person drinks enough tea to account for one fifth of their daily liquid consumption, that consumption could lower their lead intake by 3% compared with someone who drinks no tea.

This passive removal may help explain the observed relationship between tea consumption and a lower incidence of certain health issues such as heart disease, high blood pressure, and stroke, the researchers suggest. All three conditions have been associated with lead intake. But more research is needed to determine whether a direct link exists between tea consumption and metal intake, they said.

Though tea leaves can’t eliminate lead in water completely, their widespread use may help reduce an individual’s lead exposure over time.

Still, there’s no need to oversteep your morning cup, Shindel said. “I don’t think people should be changing their tea consumption patterns, or brewing really bitter tea…so they can get more metals out.”

—Skyler Ware (@skylerdware), Science Writer

Citation: Ware, S. (2025), Tea leaves remove lead from water, Eos, 106, https://doi.org/10.1029/2025EO250134. Published on 10 April 2025. Text © 2025. 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.

After decades of nondetections and tantalizing maybes, astronomers have definitively detected an aurora on Neptune. Using the James Webb Space Telescope (JWST), researchers detected an infrared auroral glow and the spectral signature of a key tracer of aurorae in Neptune’s upper atmosphere for the first time. The spectrum of this ionized molecule also suggests that Neptune’s upper atmosphere has cooled significantly since Voyager 2’s flyby 34 years ago.

Aurorae have been seen on planets and moons throughout the solar system. Theories predicted that Neptune should have aurorae, too, but previous attempts to detect them failed, said Henrik Melin, a planetary aurora researcher at Northumbria University in Newcastle upon Tyne, United Kingdom (U.K.).

“I’ve spent many, many nights up a mountain trying to detect this stuff using ground-based telescopes. You spend four nights staring at Neptune, and you see nothing,” Melin said.

This auroral detection is “completing the set” of giant planet aurorae, he added. “We have Jupiter, we have Saturn, we have Uranus. We now have Neptune.”

Chilly Aurora

Aurorae occur when charged particles from the solar wind or a nearby volcanic moon, for example, interact with a body’s magnetosphere and upper atmosphere. Some aurorae glow in visible light, like on Earth and some of Jupiter’s moons. Mercury’s aurorae shine in X-ray light.

On planets with hydrogen-dominated atmospheres like Jupiter, Saturn, and Uranus, aurorae typically glow in the infrared or ultraviolet and are traced by the presence of the trihydrogen cation (H3+). Anywhere they occur, aurorae can help scientists understand the inner workings of a planet’s magnetosphere.

“Auroral emissions provide important insight into the space environment of a planet.”

“Auroral emissions provide important insight into the space environment of a planet, and this is particularly important for Neptune, which has a very bizarre magnetic field,” said Jonathan Nichols, a planetary aurora researcher at the University of Leicester in the U.K. who was not involved with the new discovery.

Voyager 2’s brief 1989 flyby suggested that Neptune’s magnetic field is both tilted from its axis of rotation and offset from the center of the planet. The flyby also detected some hints of a possible aurora that astronomers have been hoping to confirm ever since. Models of Neptune’s atmosphere and magnetic field have suggested that Neptune’s aurorae should also be traceable by H3+ and have even predicted the longitudes at which they should appear. But detecting the aurorae proved elusive.

In June 2023, Melin and his colleagues obtained near-infrared JWST spectra of Neptune, originally intending to explore the circulation of Neptune’s middle atmosphere. The observations unexpectedly revealed an infrared auroral glow as well as a shockingly clear infrared spectrum of H3+ emitted by the planet’s upper atmosphere.

The intensity of the H3+ spectrum suggests that the upper atmosphere generating the aurora is 85°C (358 K), a significant cooldown from the 477°C (750 K) temperature measured by Voyager 2.

“It’s great to see this addition to the family portrait of solar system auroras.”

“That was quite a surprise,” Melin said.

Neptune’s seasons are roughly 41 Earth years long, so this dramatic cooling took place faster than the seasonal timescale. The researchers don’t yet understand what might be driving the cooldown, Melin said, though it is likely unrelated to the unseasonably cool summer observed elsewhere in Neptune’s atmosphere.

“The consequence of these really cold temperatures means that the auroral emissions are extremely faint,” Melin said. That explains why Neptune’s aurorae eluded the gazes of ground- and space-based telescopes before. “It was just really, really cold.”

“It’s great to see this addition to the family portrait of solar system auroras,” Nichols said. “Now we know how bright the infrared emission is, we can work out the intensity in other wavelengths such as ultraviolet, and we can run models to see what the upper atmosphere is like.”

The researchers published this discovery in Nature Astronomy.

A Neptunian Day

These JWST data were clear enough to trace aurorae to specific latitudes and longitudes, “producing the first map of the aurora at Neptune,” Melin said.

What’s more, the aurorae appeared at the exact longitudes in the southern hemisphere predicted by long-standing theories.

“This is the tantalizing starting point of really getting to understand Neptune.”

“This was not a given,” Nichols explained, “since the length of the planet’s day was determined more than 3 decades ago, and the uncertainty was such that we were supposed to have lost track of what the time is at any point on Neptune.” (Uncertainty in planetary day lengths is pretty common.)

“But it appears as if it is more accurate than we thought!” Nichols added.

Later this year, the team will point JWST at Neptune several times over the course of a month to learn more about what drives its aurorae and how the planet’s magnetosphere responds to different levels of solar activity.

“By studying the morphology of the aurorae and its changes over time, we can figure out what drives it,” Melin said. The team needs more data to do that, “but this is the tantalizing starting point of really getting to understand Neptune.”

—Kimberly M. S. Cartier (@astrokimcartier.bsky.social), Staff Writer

This news article is included in our ENGAGE resource for educators seeking science news for their classroom lessons. Browse all ENGAGE articles, and share with your fellow educators how you integrated the article into an activity in the comments section below.

Citation: Cartier, K. M. S. (2025), After 30-year search, scientists finally find an aurora on Neptune, Eos, 106, https://doi.org/10.1029/2025EO250130. Published on 10 April 2025. Text © 2025. AGU. 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’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Planets

The longer a magma chamber resides in the upper crust, the more likely it will evolve to silica-rich compositions. Volcanism has been active on Mars throughout its history, but there is an apparent lack of widespread evolved magmatism, and the development of magma storage systems has been poorly constrained.

To better understand how crustal depth and temperature profile affect the evolution and growth of magma chambers on Mars, Chatterjee et al. [2025] utilize numerical modeling and compare with recent results from the InSight lander mission. Their models suggest that Mars’ crust is divided into three zones that are consistent with InSight seismic data: (1) the upper crust where small intrusions, such as dikes, dominate the upper crust; (2) the lower crust where larger magma chambers can develop and grow; and (3) a middle zone where magma chambers can occasionally grow and produce dikes that erupt at the surface.

The depths where the three magma storage zones are located depend on the crust’s temperature gradient and this study is the first to model the longevity of magma chambers on Mars as it has gradually cooled over geological time. A higher temperature gradient during Mars’ early history (the Noachian and Hesperian time periods) would have allowed larger, more long-lived upper crustal chambers to develop with the potential to feed eruptions at the surface. Seismic activity in Cerberus Fossae detected by InSight is consistent with magmatism and suggests its continued influence on the structure and make-up of the crust of Mars.

Citation: Chatterjee, A. P., Huber, C., Head, J. W., III, & Bachmann, O. (2025). Magma chamber longevity on Mars and its controls on crustal structure and composition. Journal of Geophysical Research: Planets, 130, e2024JE008798. https://doi.org/10.1029/2024JE008798

—Mariek E. Schmidt, Associate Editor, JGR: Planets

Text © 2024. 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.

Author(s): Srimanta Maity and Garima Arora

High-field terahertz (THz) pulse generation is investigated through the interaction of an intense single-color CO2 laser pulse with helium (He) gas targets. Employing particle-in-cell (PIC) simulations, this study reveals a substantial enhancement in THz generation efficiency, even with a single-col…

[Phys. Rev. E 111, 045205] Published Thu Apr 10, 2025

The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.

On 8 May 2022, the catastrophic Baiyan rock avalanche occurred in Zhijin County, which is located in Guizhou Province, China. The digital lat/long is [26.63771, 105.69200]. I described this event at the time (on the old AGU blogsite). It destroyed 53 houses, killing three people.

Intriguingly, many of the reports of this event seem to have been removed, such as the 163.com news item and the Youtube video. This is the image of the failure that I posted at the time:-

The 8 May 2022 Baiyan rock avalanche in Bijie, Guizhou. Image from 163.com.

There is a very interesting new paper (He et al. 2025) about this event in the journal Landslides. The aim of the paper is to examine the behaviour of the particles that formed the rock avalanche using a very impressive combination of a drone survey and articial intelligence driven analysis of individual particles. This is fascinating work, which demonstrates that underlying topography plays a large role in determining the runout characteristics of individual blocks.

But along the way, the paper also provides some very interesting information about the Baiyan rock avalanche itself. First, the slope from which this failure occurred had suffered an astonishing total of seven other rock avalanches in the period between 2019 and 2022. The Google Earth image below, from March 2022 (i.e. before the Baiyan rock avalanche) shows the problems that were occurring on the slope:-

Google Earth image of the site of the 8 May 2022 Baiyan rock avalanche in China.

According to He et al. (2025), the Baiyan rock avalanche itself had a volume of 36,000 cubic metres. It had a runout distance of about 560 metres and a vertical height difference of about 455 m. Significant, but not exceptional, rainfall occurred in the days leading up to the collapse.

Tucked away towards the end of the article is a fascinating consideration of the causes of this event, and of the extraordinary cluster of failures that occurred in this area at the time. Underground coal mining was being undertaken directly below this slope – He et al. (2025) show that a panel advanced from the SW to the NE directly below the ridgeline, starting in the southwest in October 2021. In May 2022, the mining activities were occurring directly below the source area of the Baiyan rock avalanche. The implication is clearly that disturbance / subsidence caused fracturing of the rock mass, triggering the failure.

That comparatively shallow coal mining was occurring directly below such a sensitive location is perhaps surprising. This should be a classic case study of the impacts of poorly controlled mining on slope stability. I also wonder why the village was not evacuated before the landslide given the multiple failures that were occurring on the slope directly behind. It would be interesting to know more about the analyses and discussions that were occurring at this location in the early months of 2022.

Reference

He, J., Zhang, Y., Sun, P. et al. 2025. Investigation of deposition characteristics using a novel super-resolution method: a case study of Baiyan rock avalanche in Guizhou, China. Landslides. https://doi.org/10.1007/s10346-025-02512-z

Return to The Landslide Blog homepage Text © 2023. The authors. CC BY-NC-ND 3.0
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SummaryLocating earthquakes plays an important role in the study of seismic activity and geological structures. Traditional methods for locating earthquakes mainly rely on waveform matching and travel time fitting. With the development of artificial intelligence technology, machine learning methods have often been applied to locate earthquakes. However, current machine learning approaches may face challenges related to physical constraints. In this study, we build a 3D U-Net network with station distribution constraints to locate earthquakes. To improve the generalizability of the network model, we apply data augmentation techniques, including data shifting, selection, rotation, and fusion. The location results are evaluated using a testing dataset from Oklahoma, showing an average location error of about 5 km. The origin time can be determined based on the earthquake's location and the waveforms recorded by stations through waveform shifting and stacking. This method does not require the complex processing steps of traditional seismic approaches, allowing for rapid earthquake location. Additionally, we apply the network model to data recorded in Southern California through transfer learning for further application. The results show that this new method is stable and generalized, making it applicable to earthquake location problems associated with arbitrary station networks. Furthermore, we discuss the effects of data augmentation, network architecture, and the Gaussian radius of labels on the outcomes. These insights help us better understand machine learning algorithms and improve the application of deep learning in earthquake location.

SummaryEvidence of seismic anisotropy is widespread within the Earth, including from individual crystals, rocks, borehole measurements, active-source seismic data, and global seismic data. The seismic anisotropy of a material determines how wave speeds vary as a function of propagation direction and polarization, and it is characterized by density and the elastic map, which relates strain and stress in the material. Associated with the elastic map is a symmetric 6 × 6 matrix, which therefore has 21 parameters. The 21-dimensional space of elastic maps is vast and poses challenges for both theoretical analysis and typical inverse problems. Most estimation approaches using a given set of directional wavespeed measurements assume a high-symmetry approximation, typically either in the form of isotropy (2 parameters), vertical transverse isotropy (radial anisotropy: 5 parameters), or horizontal transverse isotropy (azimuthal anisotropy: 6 parameters). We offer a general approach to explore the space of elastic maps by starting with a given elastic map T. Using a combined minimization and projection procedure, we calculate the closest Σ-maps to T, where Σ is one of the eight elastic symmetry classes: isotropic, cubic, transverse isotropic, trigonal, tetragonal, orthorhombic, monoclinic, and trivial. We apply this approach to 21-parameter elastic maps derived from laboratory measurements of minerals; the measurements include dependencies on pressure, temperature, and composition. We also examine global elasticity models derived from subduction flow modeling. Our approach offers a different perspective on seismic anisotropy and motivates new interpretations, such as for why elasticity varies as a function of pressure, temperature, and composition. The two primary advances of this study are 1) to provide visualization of elastic maps, including along specific pathways through the space of model parameters, and 2) to offer distinct options for reducing the complexity of a given elastic map by providing a higher-symmetry approximation or a lower-anisotropic version. This could contribute to improved imaging and interpretation of Earth structure and dynamics from seismic anisotropy.

SummaryAutomatic event detection and phase picking are critical for processing the large volumes of data produced by modern seismological instrumentation. Accurate picking is especially challenging in Distributed Acoustic Sensing (DAS) recordings, where data quality can significantly vary along segments of the fiber due to localized environmental noise and coupling issues, reducing signal-to-noise ratios (SNR). Similarly, Ocean Bottom Seismometer (OBS) data quality also suffers from these issues. To improve accuracy under diverse conditions, we developed a novel multiband kurtosis-based picking algorithm, Kurtosis-Value-Picker (KVP), that enhances phase picking for both impulsive and emergent seismic signals. Our approach uses characteristic functions (CFs) calculated with sliding windows across multiple frequency bands. Triggers are identified based on localized kurtosis jumps over a few samples, providing greater sensitivity to emergent signals than traditional finite-difference methods. Each individual CF has its own set of triggers, adding flexibility to phase picking and retaining spectral information. We validate the KVP algorithm using earthquake data recorded with DAS on two land and submarine fiber-optic cables, as well as OBS data. We also compare its performance with a widely-cited, kurtosis-based algorithm, the widely-used FilterPicker algorithm, and the well-known PhaseNet model, using impulsive signals on nearby DAS channels as a ground truth for emergent arrivals. Our results demonstrate that KVP provides accurate picks and is suitable for complex seismic datasets.

body {background-color: #D2D1D5;} Research & Developments is a blog for brief updates that provide context for the flurry of news regarding law and policy changes that impact science and scientists today.

The Trump administration has canceled funding used to coordinate the National Climate Assessment, a major, congressionally mandated U.S. climate change report produced through the U.S. Global Change Research Program (USGCRP).

The National Climate Assessment is published approximately every four years and is the United States’ broadest assessment of current climate change impacts and climate science. 

NASA canceled a contract with ICF International, a consulting firm. ICF International was hired by the agency to support USGRCP’s logistical work and help coordinate the expansive assessment, which involves input from 15 federal agencies and hundreds of authors and contributors.

ICF previously supported the development and release of the Fifth National Climate Assessment and the Fourth National Climate Assessment. 

The change likely means the Sixth National Climate Assessment, planned for publication by early 2028, won’t be completed.

I can't say this was unexpected, but it is deeply, deeply disappointing nonetheless. The #NCA6 is now up in the air – at best.Some problems go away on their own. This is not one of them.It is coming. It's already here. You can either be prepared or unprepared.

— Cullen Hendrix (@cullenhendrix.bsky.social) 2025-04-09T16:15:43.477Z

Congress requires the Sixth National Climate Assessment to move forward, but federal officials involved in USGCRP work told Politico that the assessment is likely dead without the support of ICF International staff. Two dozen staff at the USGCRP will lose the funding to support their roles, Science reported.

 
Related

•  Trump Moves to Hobble Major U.S. Climate Change Study
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•  Trump Administration Fires Staff for Flagship U.S. Climate Assessment
•  Get Involved: AGU Science Policy Action Center
 

The move is not a surprise to those who have been following Trump’s actions on climate change. Russell Vought, the current director of the Office of Management and Budget for the Trump administration, has previously recommended ditching the National Climate Assessment and firing scientists who worked on previous editions of the report.

The cuts come alongside other efforts from the Trump Administration to undermine climate change research including cutting funding to cooperative agreements between U.S. universities and federal agencies to study Earth systems and climate change. 

—Grace van Deelen (@gvd.bsky.social), Staff Writer

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org. Text © 2024. 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.

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.

Publication date: Available online 1 April 2025

Source: Advances in Space Research

Author(s): Shuaipeng Wang, Keke Xu, Mosi Zhang

Publication date: Available online 1 April 2025

Source: Advances in Space Research

Author(s): Amsalu Hundesa Dinede, Tsegaye Kassa Gogie

Publication date: Available online 1 April 2025

Source: Advances in Space Research

Author(s): G. Manju, N. Mridula, T.V. Sruthi