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Up to 30% of life, by weight, is underground. Seismic activity may renew the energy supply for subterranean ecosystems. Published in PNAS Nexus, Eric Boyd and colleagues chronicled the ecological changes in subsurface microbial communities that took place after a swarm of small earthquakes rattled the Yellowstone Plateau Volcanic Field in 2021.

The solar system’s oddball planet has some pretty odd moons, too. The first infrared spectra of Uranus’s small inner moons, which will be presented on 18 December at the 2025 AGU Annual Meeting in New Orleans, have shown that their surfaces are much redder, much darker, and more water-poor than the larger moons orbiting far from the planet.

“We were trying to see how these properties varied across the rings and moons,” said Matt Hedman, a planetary scientist at the University of Idaho in Moscow and a coauthor on the research. “We didn’t have a lot of information about their spectra before because they’re hard to observe.”

The new observations also revealed that some moons were not quite where they should have been, highlighting how much more astronomers have to learn about the dynamics of the Uranian system.

Small, Dark, and Red

In 1986, Voyager 2 flew past Uranus in humanity’s only visit to the system. At that time, astronomers knew only of the planet’s five major moons and a handful of rings. Voyager 2 discovered 11 more moons and was able to roughly measure their sizes. Since then, scientists have used ground- and space-based telescopes to discover more than a dozen additional satellites, bringing Uranus’s moon total to 29.

Many of the more recently discovered moons are pretty tiny, from Sycorax at 150 kilometers across to Mab and Cupid at just 10 kilometers. Most of them also orbit within or just outside Uranus’s ring system, close to the much brighter planet.

All of these properties have made it tricky for astronomers to learn more about the smallest Uranian moons. That’s where the infrared powerhouse James Webb Space Telescope (JWST) comes in.

This diagram shows the orbital distances of Uranus’s inner moons and rings, to scale. Uranus is placed at the top of the diagram. Click image for larger version. Credit: Ruslik0/Wikimedia Commons, Public Domain

“Part of what makes JWST particularly good for this compared to, say, Hubble and other optical telescopes, is that in the infrared, Uranus is much fainter, so you can see the things orbiting it way more easily,” Hedman explained. What’s more, all of the spectral features the team was interested in, like water ice, occur at wavelengths that JWST can observe.

The researchers observed Uranus at several infrared wavelengths in February and got a deep look at the inner portions of the planetary system. They wanted to characterize the known small moons and search for new ones. They did discover a previously unknown moon, temporarily named S/2025 U1, orbiting just outside the epsilon ring.

Those observations also provided the first information on the infrared brightnesses of the smallest moons, many of which have remained elusive since the Voyager flyby.

“Most of the rings and inner moons show very similar properties,” Hedman said. They tend to be much redder, darker, and more water-poor when compared with the larger outer moons Miranda, Ariel, Umbriel, Titania, and Oberon.

“And then there’s Mab,” Hedman added.

The new spectra show that Mab’s surface is bluer and more water-rich than the other inner moons, said Jacob Herman, a physics graduate student at the University of Idaho and lead author on the research. In fact, its surface spectrum looks very similar to Miranda’s, the major moon that orbits closest to the rings and to Mab. Miranda’s jigsaw surface suggests a messy history.

“There is still much to be discovered about Uranus’s small inner moons, particularly regarding their origin, composition, and long-term orbital stability.”

Did the two moons encounter each other sometime during Uranus’s chaotic past? Could that encounter be related to Uranus’s mu ring, which is likely generated by material sloughing off Mab? Hedman hopes that future observations or a long-term mission to Uranus will provide those answers.

“These new measurements significantly expand our current knowledge, revealing, for instance, striking variations in the composition and reflectivity of the surfaces of moons such as Mab, Cupid, and Perdita,” said Jadilene Xavier, an astrophysicist at São Paulo State University in Guaratinguetá, Brazil, who was not involved with this research.

“There is still much to be discovered about Uranus’s small inner moons, particularly regarding their origin, composition, and long-term orbital stability,” Xavier said. “More precise data on their density, three-dimensional shape, and surface properties would be essential to determine whether these moons are fragments produced by collisions, captured objects, or primordial remnants associated with the formation of Uranus’s ring system.”

Just a Little Bit Off

Because Voyager 2 spent only a short time visiting Uranus, it could provide only limited information about the small moons’ orbital periods and distances, sometimes with large uncertainties. When the researchers compared the moons’ current positions with the positions predicted by Voyager 2 data, some of the moons were not where they seemingly should have been.

“Perdita was quite a bit off,” Herman said. “And there’s also Cupid, which was surprising.” The positions of Cordelia, Ophelia, Cressida, and Desdemona were also off, but not by much. The team is still trying to figure out whether the differences are just a matter of having more precise observations of these tiny objects or if there are unknown dynamics in play.

“These new observations are quite useful for improving our understanding of the inner Uranian system, especially its orbital dynamics.”

“These new observations are quite useful for improving our understanding of the inner Uranian system, especially its orbital dynamics,” said Matija Ćuk, who researches solar system dynamics at the SETI Institute in Mountain View, Calif.

Ćuk, who was not involved with this research, pointed out that Cordelia and Ophelia shepherd Uranus’s epsilon ring, Cressida and Desdemona are part of a pack of moons with chaotic orbits, and Perdita is known to interact with another moon, Belinda. “So the fact that these [five] moons are not in their predicted positions is valuable for understanding the system, but I wouldn’t say it’s unexpected,” Ćuk said.

These observations hint at just how many mysteries Uranus is still hiding.

“For a dynamicist like me,” Ćuk said, “knowing the precise masses of these moons would be ideal, because then we could predict their future interactions and also estimate with some confidence how stable they are on long timescales.”

Hedman and their team plan to observe the Uranian system again with JWST, are looking through archived and technical images, and hope to establish long-term monitoring to better understand the moons’ dynamics and possibly estimate their masses. The researchers are also leaning on their colleagues who simulate planetary orbits to better understand how Uranus’s moons and rings might be influencing each other.

“It’s a very dynamic and interconnected system,” Herman said.

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

Citation: Cartier, K. M. S. (2025), Uranus’s small moons are dark, red, and water-poor, Eos, 106, https://doi.org/10.1029/2025EO250442. Published on 25 November 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.

The rapid retreat of glaciers, an increasingly common phenomenon, could potentially lead to complex changes in ocean chemistry. A new study has revealed that sediment runoff from retreating glaciers is less nutritious for marine life than meltwater from stable glaciers. This finding has important implications for high-latitude marine ecosystems, such as the Gulf of Alaska, where trace metals like iron and manganese are essential for supporting microorganisms at the base of the food web.

Glacial runoff, which carries sediments produced by the relentless grinding of ice on the bedrock below, is an important source of trace metal micronutrients in the ocean. These nutrients, in turn, are essential for phytoplankton growth, which sustains the marine food web and plays a major role in absorbing atmospheric carbon dioxide.

Intrigued by the effects of climate change on nutrient availability, a team of researchers used two adjacent glaciers on Alaska’s Kenai Peninsula as a natural laboratory. One of them, Aialik Glacier, is stable and terminates on the sea, while the other, Northwestern Glacier, has retreated inland approximately 15 kilometers (9.3 miles) since 1950. Because both glaciers erode the same bedrock, the researchers knew the source material for their sediments would be nearly identical.

In late May 2022, as seasonal melting intensified, the team—led by marine chemist Kiefer Forsch, who conducted the research as a postdoctoral fellow at Scripps Institution of Oceanography and is now at the University of Southern California—collected samples from the fjords of both glaciers. Working from a small aluminum boat provided by Kenai Fjords National Park, they sampled and analyzed surface water, suspended sediments, and iceberg material, looking to analyze the concentration and bioavailability of metals like iron and manganese, as well as macronutrients such as phosphorus. (Bioavailability describes the proportion of nutrients that is readily usable by marine organisms.)

The analysis revealed important differences in the proportion of bioavailable metals in the sediment plumes. Sediments from the stable Aialik Glacier were substantially richer, with approximately 18% of the iron and 26% of the manganese in bioavailable forms. In contrast, the retreating Northwestern Glacier’s sediments contained only 13% bioavailable iron and 14%–15% bioavailable manganese. The researchers described their findings in Nature Communications.

Stale Nutrients

Researchers think this drop in bioavailable nutrients may be caused by the time lapse between when the sediments were produced and when they were released into the ocean. In the stable Aialik Glacier, which ends directly in the fjord, the sediments have a very short trip from the point of erosion to the ocean. This short distance results in fresh and labile—reactive—nutrients that microorganisms can readily use.

“The impact it could have on the ecology downstream might be muted quite a bit by its lower bioavailability.”

The retreating Northwestern Glacier’s erosive action has moved far inland. As its sediments are transported to the ocean by fluvial waters, they are chemically altered, transformed into less reactive compounds. By the time the runoff reaches the fjord, Forsch said, “it’s lost a lot of its nutritious value just by sitting there, chemically weathering.”

But that’s not the whole story. In absolute terms, the amount of bioavailable metals was similar in both fjords because the overall volume of sediment in the retreating glacier’s fjord was higher. Even if the runoff was less nutritious, researchers concluded, there seemed to be more of it.

Regardless, “the impact it could have on the ecology downstream might be muted quite a bit by its lower bioavailability,” Forsch said.

The Coast Is Not the Ocean

The implications for nutrient availability extend beyond trace metals. Glaciers that terminate in the ocean, called tidewater glaciers, provide an extra benefit by inducing powerful upwelling currents. Meltwater enters the ocean at depth and quickly rises, bringing with it deep ocean water loaded with macronutrients like nitrogen and phosphorus. Phytoplankton near the ocean surface consume these nutrients and can themselves become bioavailable to the fjord’s primary consumers like zooplankton and krill. This upwelling mechanism is what makes these fjords highly productive ecosystems.

“Losing this macronutrient supply [as tidewater glaciers retreat inland] is considered the more devastating impact for coastal ecosystems,” said Jon Hawkings, a glacial biogeochemist at the University of Pennsylvania. “There’s much more iron and manganese in these fjords than there is in the ocean by orders of magnitude; they’re limited by nitrogen mainly.”

“Once the upwelling mechanism is lost, the fjord starts to become less productive,” Forsch added.

Making things worse, when a glacier retreats onto land, its sediments are ultimately delivered at the ocean surface, creating a plume that blocks light, further inhibiting phytoplankton growth. In terms of the geochemistry and biology of these ecosystems, “it’s not really a dial, it’s a switch that occurs when a glacier retreats onto land,” he said.

While the loss of tidewater glaciers will likely lead to reduced productivity within fjords, the implications for the wider ocean are different. The Gulf of Alaska is home to very important fisheries, but its overall productivity is limited by micronutrients like iron, rather than macronutrients such as nitrogen and phosphorus. Glacial retreat might accelerate the delivery of more dissolved iron and manganese out of the fjords and onto the continental shelf, but at the same time these sediments will be less nutritious than they used to be.

In fact, Hawkings suggested, researchers might want to look “off the fjords.… This is probably where this work should go next, looking at these plumes as they exit the fjords into the Gulf of Alaska.”

The study “opens up a number of new questions,” Hawkings said, but much more research is needed to answer them. “What is the impact…for marine productivity? Is this just a one-off? Should we go back to the same place and test again? What about other places like Greenland, Alaska and Patagonia? … The jury is still out in my view.”

—Javier Barbuzano (@javibar.bsky.social), Science Writer

Citation: Barbuzano, J. (2025), Glacier runoff becomes less nutritious as glaciers retreat, Eos, 106, https://doi.org/10.1029/2025EO250431. Published on 25 November 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.

The Hayli Gubbi volcano in northeast Ethiopia, believed to have been dormant for up to 12,000 years, erupted on 23 November 2025, sending a massive plume of ash and sulfur dioxide high into the atmosphere.

This is an authorized translation of an Eos article. Esta es una traducción al español autorizada de un artículo de Eos.

Gestionar los incendios en bosques tropicales puede ser una tarea muy abrumadora: los taladores y los pirómanos comúnmente se mueven más rápido que los equipos de primera intervención, los recursos son escasos y el territorio es inmenso. En la Amazonia Brasileña, estos obstáculos aprietan a un sector ambiental que crónicamente ha recibido pocos fondos, cuyos agentes de campo enfrentan amenazas de granjeros y, cada vez más, de el crimen organizado.

En 2024, los incendios arrasaron con 30.8 millones de hectáreas en Brasil, un 79% más que en 2023. Más del 80% del área total que se quemó se encontraba dentro de la Amazonia Legal, según la plataforma de datos ambientales MapBiomas (La Amazonia Legal es una región designada por el gobierno que comprende los 9 estados que están en la cuenca del Amazonas). Debido a la escala de los incendios, en agosto de 2024, el Instituto Brasileño del Ambiente y Recursos Naturales Renovables de Brasil (IBAMA, por sus siglas en portugués) incrementó la cantidad de vigilantes a 2 227 brigadistas (bomberos), con 1 239 de ellos – más de la mitad – con base en la Amazonia Legal.

Millones de hectáreas en Acre

Acre es el estado más al oeste de Brasil, colinda con Perú y Bolivia y es parte de la Amazonia Legal. En Acre, cuatro brigadas de incendios profesionales con 68 bomberos de tiempo completo operan en tres municipalidades y un área protegida. Una brigada voluntaria también opera en la ciudad más grande, que también es la capital, Rio Branco.

Con cerca de 14 millones de hectáreas de bosque que patrullar, estos grupos apenas pueden cubrir una fracción del territorio de Acre.

Resulta que la ciencia ha sido una herramienta importante para llenar el hueco, ya que el desafío de combatir el fuego en Acre no es solo sobre la falta de grupos en el campo; también está relacionada al acceso de datos. La información ambiental de Brasil está esparcida a lo largo de varias agencias: El Instituto Nacional de Investigación Espacial (INPE, por sus siglas en portugués), agencias ambientales federales como el IBAMA y el Instituto Chico Mendes para la Conservación de la Biodiversidad, la agencia Nacional de Agua (ANA, por sus siglas en portugués), y el centro Nacional para Monitoreo y Alertas de Desastres Naturales de Brasil, así como secretarías individuales de estado, cada una trabajando con sus propias prioridades y cadencias.

Sin datos arreglados en formatos compatibles, algunos de ellos se pueden sobrelapar o contradecir. “Para saber dónde tenemos que actuar, necesitamos información calificada, tenencia de tierras, zoneamientos y puntos calientes de incendios. Sin eso, cualquier política pública para incendios o deforestación va a ser inefectiva en el Amazonas”, dijo Claudio Cavalcante, jefe del Centro para Geoprocesamiento Ambiental (CIGMA, por sus siglas en portugués), el centro geoespacial que Acre creó dentro de la Secretaría del Ambiente en 2020 para conectar la deforestación y el monitoreo de incendios con la respuesta de políticas públicas.

CIGMA ha hecho los esfuerzos de integrar los datos de todas las agencias estatales y federales de Brasil para informar a los agentes en el campo. “Hemos trabajado con estratificación de datos: deforestación [en áreas] de 1 a 5 hectáreas y luego de 10 a 50. Automatizar algunos flujos de datos ha sido un trabajo muy complejo y laborioso” añadió Cavalcante, quien formó parte de una junta con investigadores, comunicadores y expertos en políticas públicas en las oficinas centrales del CIGMA en julio.

La mirada en los datos

Toda la integración sucede en el Cuarto de Situaciones de CIGMA, donde científicos y analistas evalúan alertas de incendio en vivo, niveles de los ríos, lluvia, índices de sequía y otra cantidad de datos.

“Todos los mapas para la acción en el campo se desarrollan aquí. También preparamos los reportes y notas técnicas mensuales de la deforestación”, dijo Quelyson Souza, quien coordina el Grupo de Mando y Control Ambiental de la Secretaría Ambiental de Acre.

Quelyson Souza, quien coordina el Grupo de Comando y Control Ambiental de Acre, explica cómo las alertas de tala funcionan y cómo esos datos pueden ser integrados en las respuestas para el combate a los incendios. Crédito: Bibiana Garrido/IPAM Amazonia

El sistema de CIGMA fusiona las alertas de incendios del INPE con los datos de tenencia de tierras y zoneamiento para identificar potenciales infractores. Los datos hidrogeológicos de ANA, la agencia de agua, se actualizan cada 15 minutos y alimentan los datos de la Defensa Civil y el Departamento de Incendios del estado. Los sensores de calidad del aire detectan humo que viene de la selva dentro y fuera de los límites de Brasil.

Para el coordinador de las Operaciones de Protección Ambiental del Cuerpo de Bomberos de Acre, el Mayor Freitas Filho, los datos científicos a los que sus cuerpos tienen acceso en el campo “son esenciales para optimizar y refinar el uso de los recursos operacionales”. El departamento de incendios de Acre lidera la Operación Controlada de Incendios, la cual se enfoca en integrar los equipos de agentes militares y ambientales para combatir los incendios en la estación seca, que abarca la segunda mitad del año.

Según un informe de manejo de incendios en la selva del Amazonas publicados este mes por el Instituto de Investigación Ambiental de la Amazonia (IPAM Amazônia), Acre tiene un modelo muy efectivo para vincular datos y gobernanza que recomienda sistemas de alerta temprana e intercambio abierto de datos para que las municipalidades puedan actuar de forma rápida.

Lecciones de Acre

A pesar de los desafíos, Acre resalta como uno de los pocos estados Amazónicos donde científicos, bomberos y creadores de políticas públicas comparten un mismo cuarto.

“Es inspirador ver la evolución del Cuarto de Situación de Acre. Lo uso como un ejemplo nacional porque la acción sucede en el campo, incluso más allá de las fronteras”, dijo Liana Anderson, una investigadora de percepción remota en el INPE.

“Es mucho más difícil que nos engañen los delincuentes que quieren salirse con la suya con sus delitos medioambientales”

Mientras Brasil se prepara para albergar la COP30 (la Conferencia de Cambio Climático de las Organización de las Naciones Unidas) en Belém, científicos y tomadores de decisiones esperan que la experiencia de Acre pueda ser un ejemplo de manejo del ambiente centrado en la ciencia: las bases de datos unificadas, los paneles compartidos y la colaboración pueden convertir a la información en planeación y acción.

“Cuando tenemos una idea más clara con la información a la que tenemos acceso ahora, es mucho más difícil que nos engañen los delincuentes que quieren salirse con la suya con sus delitos medioambientales”, dijo Souza. “Es como cuando te levantas la venda de un ojo cuando estas jugando a la gallina ciega”

—Meghie Rodrigues (@meghier.bsky.social), Science Writer

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.

This translation by Anthony Ramírez-Salazar (@Anthnyy) was made possible by a partnership with Planeteando and GeoLatinas. Esta traducción fue posible gracias a una asociación con Planeteando and GeoLatinas.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Earth’s Future

Groundwater supports billions of people, but many regions are removing it from aquifers faster than nature can refill them. Bhalla et al. [2025] examine the concept of “peak groundwater”, the moment when use reaches its maximum and begins to decline due to physical, economic, or policy limits. The authors trace how climate pressures, population growth, and management choices interact to determine when those limits arrive. They show that peak groundwater is not only a physical threshold but also a social and institutional one, shaped by how communities plan for scarcity.

The review offers a clear framework for recognizing early signs of stress and explores practical actions that can extend the life of aquifers. By bringing together insights across disciplines, it lays out pathways for governments, water managers, and communities to respond proactively. This synthesis offers a timely guide for protecting groundwater in an era of rising uncertainty.

Citation: Bhalla, S., Cherry, J. A., Konikow, L. F., Taylor, R. G., & Parker, B. L. (2025). Peak groundwater: Aquifer-scale limits to groundwater withdrawals. Earth’s Future, 13, e2025EF006221. https://doi.org/10.1029/2025EF006221

—Kelly Caylor, Editor-in-Chief, Earth’s Future

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.

Earth's ocean, the planet's life-support system, is experiencing rapid and widespread transformations that extend far below its surface. A promising international study published in Nature Climate Change reveals that vast regions of the global ocean are experiencing compound state change, with simultaneously warming, becoming saltier or fresher, losing oxygen, and acidifying—clear indicators of climate change pushing marine environments into uncharted territory.

Mountains worldwide are experiencing climate change more intensely than lowland areas, with potentially devastating consequences for billions of people who live in and/or depend on these regions, according to a major global review.

Earthquake forecasting tools powered by AI can forecast the risk of aftershocks seconds after the initial tremor, a new study suggests. The machine learning models can forecast where, and how many, aftershocks will take place following an earthquake in close to real-time, researchers say.

SummaryThree-dimensional (3-D) forward modeling of magnetotelluric (MT) data remains a computationally challenging task, particularly when accurate broadband MT responses are simulated for real-world problems that often involve complex multi-scale bathymetry and/or topography. To overcome this challenge, we developed a new efficient numerical approach for 3-D MT forward modeling that combines high-order Nédélec-type finite elements and high-order meshes, allowing us to obtain superior accuracy and account for complex material boundaries and interfaces. Despite gains in accuracy, higher-order FE solvers are often considered impractical owing to higher memory consumption and a more ill-conditioned system. To overcome these limitations, we use an iterative solver accelerated by the Low-Order-Refined (LOR) preconditioner, which uses spectrally equivalent low-order operators, rendering the complexity independent of the polynomial degree. Another key novelty is a matrix-free implementation, where the action of the high-order operator is computed efficiently without explicit matrix assembly. The low-order system is solved using an Auxiliary Space Maxwell (AMS) solver based on a multigrid solver. We demonstrate the efficiency in a series of numerical experiments. Scalability analysis on a 3-D benchmark model demonstrates that the LOR preconditioner significantly outperforms the current state-of-the-art AMS preconditioner in terms of CPU time and memory usage, especially for higher polynomial degrees. Excellent scalability is confirmed by solving a problem with up to 1.5 × 109 degrees of freedom in less than 2 minutes using 16,384 CPU cores, which is, to our knowledge, the largest 3-D MT problem reported to date. We also illustrate that high-order hexahedral meshes allow for accurate discretization of complex geometries, such as topography, with substantially fewer elements than conventional linear meshes. Finally, the capability of the integrated approach is demonstrated on a real 3-D model crossing the ocean trench in the Aleutian subduction zone. The proposed methods pave the way for more efficient and accurate 3-D MT modeling that is crucial for the inversion of complex MT data sets.

SummaryAtmospheric models are based on various types of geophysical data, including lidar and radar. Infrasounds, acoustic waves that can propagate over large distances, have not yet been used in atmospheric models, although they provide valuable information. Besides their sensitivity to atmospheric phenomena such as gravity waves, infrasound also presents the advantage of being omnipresent. Previous studies explored the use of infrasound packet arrival properties for model estimation. However, properties such as arrival times present less information than full waveforms. We aim here to investigate, for the first time, the sensitivity of a full infrasound waveform to model parameters and to use these sensitivities in an inverse problem to recover atmospheric structure. For this purpose, infrasound propagation is modeled by Euler equations (i.e. Navier-Stokes equations in the absence of attenuation effects), and discretization is carried out here using the finite-differences method. Waveform sensitivity to atmospheric parameters is computed through the adjoint method via a novel and optimized double checkpointing-based procedure and validated by comparison with a small perturbation method. As an illustration, these sensitivity kernels are computed for the idealized case of an explosion in Finland, recorded by a CTBT station. These first results demonstrate the high sensitivity of infrasound waveforms to the atmospheric perturbations generated by gravity waves. Moreover, the sensitivity kernels of infrasound waveforms allow us to recover the variations of model parameters by solving an inverse problem. To demonstrate this capability, full waveform non-linear inversions are performed using the Limited Broyden-Fletcher-Goldfarb-Shanno method (L-BFGS): wind and sound speed profiles are inverted for a test case with idealized conditions and a synthetic dataset. These estimates of infrasound sensitivity kernels are closing a knowledge gap that allows the use of infrasound full waveforms to constrain atmospheric models.

SummaryPortland cement remains the most widely used construction material globally, valued for its well-documented properties and performance. However, its production generates substantial CO₂ emissions, mainly due to the decomposition of limestone (CaCO₃) into calcium oxide during clinker formation. In response to these environmental concerns, researchers have been actively exploring ways to lower cement’s carbon footprint and improve its sustainability. One effective strategy involves reducing the clinker content by incorporating supplementary cementitious materials (SCMs). To ensure SCMs enhance performance without compromising safety, it is essential to investigate the properties of blended cements. Natural zeolites have emerged as promising SCMs. Although they do not possess inherent cementitious properties, finely ground zeolites can react with calcium hydroxide in the presence of water, contributing to strength development. This study examines the potential of natural zeolites as SCMs and utilizes the spectral induced polarization (SIP) method to monitor cement hydration and reaction mechanisms. Portland cement mortars containing 25% zeolite were prepared and compared against two reference mixes. Zeolites were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), while SIP monitoring was conducted continuously over 28 days. Our results reveal that SIP responses are influenced by the specific chemical composition of the mortar. The incorporation of SCMs alters cement chemistry, significantly influencing SIP signals. Over time, we observed an increase in the imaginary conductivity component and a decrease in the real conductivity component. SEM analysis showed the formation of new fibrous mineral habits in zeolite-blended samples, alongside a reduction in pore fluid content. These observations suggest a strong connection between SIP signals and mineralization processes, likely associated with the formation of secondary gels and calcium monosulfoaluminate. The interaction of zeolites with calcium hydroxide promotes the development of calcium aluminate hydrates, which then react with ettringite to form calcium monosulfoaluminate. These results emphasize the importance of studying SIP behavior in cement systems containing SCMs, as assumptions based on ordinary Portland cement may lead to misinterpretations. Our research underscores the potential of SIP as a valuable tool for monitoring cement hydration while offering new insights into the chemical transformations in zeolite-containing mortars. Ultimately, this work contributes to the advancement of more sustainable cement formulations, supporting environmentally responsible construction practices.

Many ecosystems on Earth are affected by pulses of activity: temperature swings between seasons, incoming and outgoing tides, the yearly advent of rainy periods. These variations can play an important role in providing nutrients and other important inputs, but climate change often makes the amplitude of these pulses more extreme, with sometimes catastrophic results.

Florida State University oceanographers have discovered a significant connection between small-scale microbial processes and ecosystem-wide dynamics, offering new insights into the mechanisms driving marine carbon storage.

Climate change is accelerating the reorganization of river-lake systems on the Qinghai-Tibet Plateau, reshaping hydrological and ecological processes in the "Asian Water Tower."

Sixty-million-year-old rock samples from deep under the ocean have revealed how huge amounts of carbon dioxide are stored for millennia in piles of lava rubble that accumulate on the seafloor.

Tropical cyclones can unleash extensive devastation, as recent storms that swept over Jamaica and the Philippines made unmistakably clear. Accurate weather forecasts that buy more time to prepare are crucial for saving lives and are rooted in a deeper understanding of climate systems.

A University of Houston scientist has teamed with international partners to examine how Antarctica's massive glaciers are shifting and how that could predict sea level changes. Their latest collaboration offers the most precise mapping to date in Antarctica of grounding lines, the points where glaciers lift from bedrock and begin to float on the ocean.

Despite continuous efforts to evaluate and predict changes in Earth's climate, most models still struggle to accurately simulate extreme precipitation events. Models like the Coupled Model Intercomparison Project Phases 5 and 6 (CMIP5 and CMIP6) use fairly coarse resolution due to computing constraints, making it a little easier, faster and less expensive to run simulations, while still providing some degree of accuracy.

New study reveals burning of fossil fuels is accelerating winter rainfall changes in the UK and Europe, almost 25 years sooner than expected.