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

Los castores construyen presas en los ríos. Las hormigas construyen montículos y excavan túneles. Los peces que buscan alimento desplazan partículas en los lechos de los ríos. El ganado doméstico compacta el suelo bajo sus pezuñas. Durante décadas, los investigadores han documentado las formas en que diversas especies modifican sus ambientes. Sin embargo, aún no está claro cuál es el impacto de todo este movimiento de tierra.

“La biología compite con las fuerzas geofísicas en la transformación de los paisajes”.

Una nueva investigación estima que los animales silvestres invierten anualmente 76,000 gigajulios de energía en la transformación de los paisajes terrestres, una cantidad equivalente a la de cientos de miles de inundaciones extremas. La contribución energética del ganado excede esta cifra en tres órdenes de magnitud.

“Existe la idea de que estos son procesos curiosos, únicos o inusuales”, señaló Gemma Harvey, coautora del estudio y geógrafa física en la Universidad Queen Mary de Londres, Reino Unido. Los investigadores frecuentemente piensan que el impacto geomorfológico—o moldeador del paisaje—de los animales es interesante, pero no particularmente significativo, explicó. Sin embargo, la nueva investigación demuestra que “la biología compite con las fuerzas geofísicas en la transformación de los paisajes”.

Harvey y sus colegas se sumergieron en la literatura científica en busca de estudios sobre las acciones geomórficas de los animales. Basados en investigaciones en inglés sobre ecosistemas terrestres y de agua dulce, el equipo identificó 500 especies que realizan actividades como mezcla del suelo, excavación, construcción de madrigueras, pisoteo del terreno y edificación de montículos y presas.

Más de una cuarta parte de estas especies están amenazadas, en declive o presentan tendencias poblacionales desconocidas de las que los científicos saben poco o nada. “Sus procesos geomórficos podrían desaparecer de los paisajes antes de que comprendamos su importancia”, advirtió Harvey.

Los investigadores calcularon cuánta energía invierten estas 500 especies en la transformación de los ecosistemas terrestres y de agua dulce. Según Harvey, los datos sobre la energía que gastan las criaturas en actividades biomórficas son escasos. Los valores existentes varían desde menos del 1% del gasto energético diario hasta más del 40% en especies como las lombrices de tierra, que pasan mucho tiempo excavando. Para 495 especies de fauna silvestre y cinco tipos de ganado (bovinos, caballos salvajes, cabras, ovejas y yaks), el equipo estimó la energía geomórfica colectiva considerando la abundancia global de cada especie y asumiendo que el 1% de su presupuesto energético total se destina a la modificación del suelo.

“Y aun usando ese valor conservador, la magnitud de la contribución de los animales es impresionante”.

“Utilizaron un valor muy sólido y conservador”, afirmó Clive Jones, ecólogo del Instituto Cary de Estudios de Ecosistemas en Millbrook, Nueva York, quien no participó en la investigación. “Y aun usando ese valor conservador, la magnitud de la contribución de los animales es impresionante”.

Los 76,000 gigajulios que los animales silvestres invierten anualmente en la remodelación de la superficie terrestre equivalen a 200,000 temporadas de monzones o 500,000 inundaciones extremas de ríos. Y esta cifra ni siquiera contempla los océanos o las zonas costeras.

El ganado gasta un estimado de 34.5 millones de gigajulios—450 veces más que los animales silvestres—en procesos geomórficos incluyendo el pisoteo del suelo.

Es probable que la estimación de los animales salvajes subestime su impacto total, ya que muchas especies que remueven la tierra, especialmente insectos, aún no han sido descubiertas (Las acciones de animales de gran tamaño, como la excavación de osos o el hozamiento de jabalíes, están bien documentadas). Además, los datos sobre puntos críticos de biodiversidad, como los trópicos, son más escasos en comparación con los de entornos templados del hemisferio norte.

Los investigadores publicaron sus resultados en Proceedings of the National Academy of Sciences of the United States of America.

Características de las criaturas

Ha existido un debate constante entre los geomorfólogos sobre la importancia real de las acciones de los animales, señaló Jones. “¿Se puede medir un efecto neto?” Hasta ahora, la cantidad de datos no es lo suficientemente extensa para responder a esa pregunta, agregó, pero este nuevo estudio representa “una forma muy legítima e innovadora de comenzar a abordar este problema”. Una de las dificultades para contabilizar los efectos de los animales es que la variedad de acciones que realizan supera con creces el número de procesos geomórficos físicos, explicó.

Un análisis completo del impacto de los animales debería incluir los ecosistemas costeros y marinos, donde organismos que van desde gusanos y crustáceos hasta marsopas y peces alteran los sedimentos del fondo marino. De hecho, la Gran Barrera de Coral es la mayor estructura zoogeomórfica de la Tierra, excluyendo aquellas construidas por humanos, señaló Ilya Buynevich, geólogo de la Universidad de Temple en Filadelfia, quien no participó en el estudio.

Los investigadores también podrían analizar cómo diferentes organismos interactúan en ciertos entornos y generan efectos en cascada, sugirió Harvey. Por ejemplo, las actividades de algunos herbívoros modifican la fauna del suelo subterráneo. Otras especies pueden afectar sus ambientes solo cuando alcanzan un umbral poblacional. Los anfípodos que habitan en aguas subterráneas, por ejemplo, pueden mantener la porosidad de los sedimentos de los acuíferos, pero solo si su densidad poblacional es lo suficientemente alta, explicó Harvey. La nueva investigación se centró casi exclusivamente en los efectos de los animales dentro de su rango de distribución natural; futuros estudios podrían considerar los efectos de especies invasoras o introducidas.

Para la mayoría de los científicos, incluso los ecólogos, los procesos no biológicos suelen considerarse “fundamentales”, señaló Buynevich. Sin embargo, el papel de los animales en la transformación del paisaje debería tomarse en cuenta en iniciativas de conservación, como la reintroducción de especies y la restauración ecológica. Además, estos procesos no suelen estar representados en los modelos de evolución del paisaje. Los científicos de la Tierra que buscan las fuerzas que han modelado los entornos a menudo no consideran lo que los animales podrían haber hecho, afirmó.

Por ejemplo, Buynevich investiga los procesos geomórficos en entornos costeros donde los científicos suelen atribuir ciertas formaciones a tormentas intensas o tsunamis para explicar las características que observan. Sin embargo, advirtió, “hay una gran posibilidad de que esas anomalías que observo en playas milenarias… sean nidos de tortugas marinas”. Los científicos deberían, al menos, considerar la posibilidad de que algunas estructuras sean de origen biológico, concluyó.

—Carolyn Wilke (@CarolynMWilke), Escritora de ciencia

This translation by Saúl A. Villafañe-Barajas (@villafanne) was made possible by a partnership with Planeteando and Geolatinas. Esta traducción fue posible gracias a una asociación con Planeteando y Geolatinas.

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.

Author(s): Arno Vanthieghem and Amir Levinson

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As atmospheric rivers pounded the U.S. West Coast last winter, scientists deployed increasingly advanced observing tools over the Pacific Ocean to improve forecasts of the powerful storms.

In 1638, an earthquake in what is now New Hampshire and Plymouth, Massachusetts, left colonists stumbling from the strong shaking and water sloshing out of the pots used by Native Americans to cook a midday meal along the St. Lawrence River, according to contemporaneous reports.

At the Seismological Society of America's Annual Meeting, researchers posed a seemingly simple question: how wide are faults?

Sediment cores drawn from four lakes in Guatemala record the distinct direction that ground shaking traveled during a 1976 magnitude 7.5 earthquake that devastated the country, according to researchers at the Seismological Society of America's Annual Meeting.

The cold outer reaches of the solar system are home to a plethora of small worlds, many of which have moons of their own. For a few, the moon is massive enough to make the pair into a binary; the Pluto-Charon system is the most famous of those. And a small icy body named Lempo is a trinary: three objects of comparable mass in mutual orbit.

Now astronomers have identified another possible trinary object, a very distant world known as Altjira (al-TCHEE-ruh), named to honor the creator deity in Arrernte Australian cosmology. Observers discovered Altjira in 2001 and its as yet unnamed moon in 2006. With data accumulated over the past 2 decades, researchers determined the path of the moon doesn’t match what would be expected if it were orbiting a spherical (or mostly so) world.

“Our modeling tells how squished the central object is.”

“When we take images [of Altjira], we just see two objects, and we can track those two objects gravitationally,” said Benjamin Proudfoot, an astronomer at the Florida Space Institute who led the observational part of the project. “We can see that the orbit precesses, and precession is caused by the nonspherical shape of one of the objects. Our modeling tells how squished the central object is.”

In fact, the analysis showed the central object was too squished to be one single body: It is almost certainly two, making Altjira the second known trinary beyond Neptune. And that’s a big deal.

“One of the primary goals of planetary science is kind of understanding how things formed,” Proudfoot said, noting that these trans-Neptunian objects (TNOs) are remnants of the earliest days of our solar system. One major theory explaining the formation of the solar system, known as streaming instability, predicts the formation of a number of trinaries.

“Finding triples like Altjira is really important for telling us how we got here,” Proudfoot explained. “Although this icy debris is in the outer solar system, this was the first step into forming the planets that we have today.”

Proudfoot and his colleagues published their results in The Planetary Science Journal.

One Lump or Two?

Binary systems are common throughout the known cosmos: two objects of comparable mass orbiting each other, such as Pluto and Charon or even Earth and the Moon.

A similar type of system exists where three bodies of comparable mass mutually orbit each other: a hierarchical triple. Lempo, Hiisi, and Paha (named for figures in Finnish mythology) are such a trinary: Lempo and Hiisi form a close pair, with Paha orbiting both in a wider path. Altjira is 44 times farther from the Sun than Earth is; if it is a hierarchical triple, it is too far away, and its inner pairing is too tight for even the most powerful telescopes to resolve. Upcoming observations with NASA’s James Webb Space Telescope (JWST) are unlikely to provide direct evidence, though they will help the indirect case.

Without direct observation, indirect measurements showed Altjira’s companion has a precessing orbit, meaning it traces a sort of spirograph pattern rather than a circle or ellipse. That indicates Altjira must actually be two objects, either in mutual orbit like Lempo and Hiisi or stuck together, like the TNO Arrokoth.

To model the shape and nature of Altjira, Proudfoot and his coauthors—including Maia Nelson, who at the time was an undergraduate student at Brigham Young University in Utah—used detailed motion of the object’s companion and worked backward.

“The most likely thing is [Altjira] is a triple system,” Proudfoot said. “Slightly less likely, but not unreasonable, would be something like Arrokoth with a moon.”

The existence of hierarchical triples helps reveal how the solar system formed from its primordial protoplanetary disk of dust and gas. According to the streaming instability theory, a sort of gravitational drag slowed the larger molecules in that disk, allowing them to clump together into larger aggregates. Some of those objects grouped into binaries, and others grouped into hierarchical triples. But the question remains how stable these trinaries would be over billions of years because many things can separate the outermost member of the triad, including the simple passage of time.

“We don’t have money to send spacecraft to all the objects we think are interesting.”

“A trinary configuration like Lempo favors the streaming instability theory,” said Flavia Luane Rommel, an astronomer at the University of Central Florida who has previously worked with Proudfoot but was not part of the Altjira study. One trinary could be a special case, she noted, but the confirmed identity of two triples means there are likely more that have yet to be detected—lending strong support to the streaming instability theory.

More direct evidence of Altjira’s nature requires further observations.

Although JWST will provide some data, “we don’t have money to send spacecraft to all the objects we think are interesting,” Rommel said.

To study such objects, astronomers in her area of research often use stellar occultations: a sort of miniature eclipse in which the object they want to study passes in front of a star. If Altjira is a trinary, an occultation would result in one eclipse for each object blocking the star. “The thing is, stellar occultations are not in our control, they don’t happen when we want them to,” she said.

Proudfoot noted that Altjira’s unnamed moon could provide data similar to those supplied by stellar occultations, however, because the moon’s orbit takes it between Earth and Altjira’s mysterious inner body, an event called a mutual planetary occultation or, simply, a mutual event.

Watching a mutual event’s subtle fluctuations in reflected light could reveal whether the object is a pair or a lumpy single object like Arrokoth. Mutual events are how scientists measured the properties of the binary asteroids Didymos and Dimorphos before sending the Double Asteroid Redirection Test (DART) mission.

“That is imminently doable,” Proudfoot said. “I am working on getting telescope time right now to observe a mutual event in October of this year.”

—Matthew R. Francis (@BowlerHatScience.org), Science Writer

Citation: Francis, M. R. (2025), Distant icy twins might actually be triplets, Eos, 106, https://doi.org/10.1029/2025EO250149. Published on 18 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.

Source: AGU Advances

As the climate warms, drought conditions are intensifying in many parts of the world. The effects of hydrological drought on water levels in rivers and other waterways are especially crucial to monitor because they can affect regional agriculture, energy production, economic stability, and public health.

Historical rainfall and river flow data exist from only as far back as a few decades to 200 years, depending on the location, time spans too short to assess long-term hydrological behavior accurately. Climate change adds more uncertainty, as historical data are less likely to correlate with potential future conditions. Tree ring widths, which reflect the dry or wet conditions affecting tree growth annually, provide valuable proxy climate data from before historical recordkeeping began.

Guo et al. combined limited historic river flow observations, climate model simulations, and paleohydrologic reconstructions from tree ring proxy data to examine how hydrological drought has evolved since 1100 CE—and how it may continue changing until 2100 CE—in northern Italy’s Po River basin. This basin supports about 40% of the country’s gross domestic product and 45% of its hydropower, and it has a known history of worsening drought conditions since 2000.

The work revealed agreement between paleohydrologic reconstructions and climate model simulations of past droughts, including some during the Medieval Climate Anomaly (900–1300 CE) and the Little Ice Age (1350–1600 CE). Those droughts lasted nearly 40 years and appeared to be much more extreme than modern droughts. The agreement between the reconstructions and modeling of past conditions provided support for the team’s projections of future drought, according to the authors.

These projections indicated alarming trends, such as river flow possibly dropping below levels seen during those historically dry periods: The team’s models suggested a 10% drop in annual average flow of the Po in the 21st century compared to the average levels recorded between 1100 and 2014. Also, though the models suggested fewer droughts will occur in the 21st century, those that do occur will be 11% longer and 12% more severe as climate change reduces water availability and human activities demand more water.

The researchers note that their findings may help this Alpine region and others like it to adapt to the dryer conditions to come. (AGU Advances, https://doi.org/10.1029/2024AV001393, 2025)

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

Citation: Owen, R. (2025), Modeling the past, present, and future of drought, Eos, 106, https://doi.org/10.1029/2025EO250148. Published on 18 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.

SummaryLong-period seismic events (LPs) are observed within active volcanoes, hydrothermal systems, and hydraulic fracturing. The prevailing model for LP seismic events suggests that they result from pressure disturbances in fluid-filled cracks that generate slow, dispersive waves known as Krauklis waves. These waves oscillate within the crack, causing it to act as a seismic resonator whose far-field radiations are known as LP events. Since these events are generated from fluid-filled cracks, they have been used to analyze fluid transport and fracturing in geological settings. Additionally, they are deemed precursors to volcanic eruptions. However, other mechanisms have been proposed to explain LP seismicity. Thus, a robust interpretation of these events requires understanding all parameters contributing to LP seismicity. To achieve this, for the first time, we have developed a physical model to investigate LP seismicity under controlled-source conditions. The physical model consists of a 30 cm × 15 cm × 0.2 cm crack embedded within a concrete slab with dimensions of 3 m × 3 m × 0.24 m. Using this apparatus, we investigate fundamental factors affecting long-period seismic signals, including crack stiffness, fluid density and viscosity, radiation patterns, and triggering location. Our findings are consistent with the theoretical model for Krauklis waves within a fluid-filled crack.In this study, we examine the interplay between fluid properties and characteristics of waves within and radiated from the crack model. Records from a pressure transducer within the crack model have the same frequency characteristics as the surface sensors, indicating that the surface sensors are recording the crack waves. Because the crack stiffness parameters for all the fluids are relatively high, fluid density variations have a larger effect on the crack wave frequency, with higher density fluids yielding lower resonance frequencies. Similarly, the quality factor (Q) decreases with increasing fluid density. We also find that an increase in fluid viscosity along with the increased fluid density results in a decrease in resonance frequency and Q. Trigger locations at the middle of the crack length and width most effectively resonated the first and second transverse modes. Thus, this physical model can offer new horizons in understanding LP seismicity and bridge the gap between theoretical models and observed LP signals.

SummaryMany geophysical studies require knowledge on the present-day temperature distribution in Earth’s mantle. One example are geodynamic inverse models, which utilize data assimilation techniques to reconstruct mantle flow back in time. The thermal state of the mantle can be estimated from seismic velocity perturbations imaged by tomography with the help of thermodynamic models of mantle mineralogy. Unique interpretations of the tomographically imaged seismic heterogeneity can either be obtained by incorporating additional data sets or requires assumptions on the chemical composition of the mantle. However, even in the case of (assumed) known chemical composition, both the seismic and the mineralogical information are significantly affected by inherent limitations and different sources of uncertainty. Here, we investigate the theoretical ability to estimate the thermal state of the mantle from tomographic models in a synthetic closed-loop experiment. The ‘true’ temperature distribution of the mantle is taken from a 3-D mantle circulation model with Earth-like convective vigour. We aim to recover this reference model after: 1) mineralogical mapping from the ‘true’ temperatures to seismic velocities, 2) application of a tomographic filter to mimic the effect of limited seismic resolution, and 3) mapping of the ‘imaged’ seismic velocities back to temperatures. We test and quantify the interplay of tomographically damped and blurred seismic heterogeneity in combination with different approximations for the mineralogical ‘inverse’ conversion from seismic velocities to temperature. Owing to imperfect knowledge of the parameters governing mineral anelasticity, we additionally investigate the effects of over- or underestimating the corresponding correction to the underlying mineralogical model. Our results highlight that, given the current limitations of seismic tomography and the incomplete knowledge of mantle mineralogy, magnitudes and spatial scales of a temperature field obtained from global seismic models deviate significantly from the true state, even in the idealized case of known bulk chemical composition. The average deviations from the reference model are on the order of 50–100 K in the upper mantle and – depending on the resolving capabilities of the respective tomography – can increase with depth throughout the lower mantle to values of up to 200 K close to the core-mantle boundary. Furthermore, large systematic errors exist in the vicinity of phase transitions due to the associated mineralogical complexities. When used to constrain buoyancy forces in time-dependent geodynamic simulations, errors in the temperature field might grow non-linearly due to the chaotic nature of mantle flow. This could be particularly problematic in combination with advanced implementations of compressibility, in which densities are extracted from thermodynamic mineralogical models with temperature-dependent phase assemblages. Erroneous temperatures in this case might activate ‘wrong’ phase transitions and potentially flip the sign of the associated Clapeyron slopes, thereby considerably altering the model evolution. Additional testing is required to evaluate the behaviour of different compressibility formulations in geodynamic inverse problems. Overall, the strategy to estimate the present-day thermodynamic state of the mantle must be selected carefully to minimize the influence of the collective set of uncertainties.

To protect against rising sea levels in a warming world, coastal cities typically follow a standard playbook with various protective infrastructure options. For example, a seawall could be designed based on the latest climate projections, with the city officials then computing its cost-benefit ratio and proceeding to build, accordingly.

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

Warm western boundary currents play a role in lateral transport of heat, salt, and biogeochemical tracers, including nutrients. When these poleward western boundary currents separate from the coast to the east, they seem to drag biologically productive water from near shore regions to offshore. Cross-shelf lateral flows have, therefore, been considered a cause of offshore phytoplankton blooms. However, these currents generate and interact with mesoscale eddies after they separate from the coast.

Chapman et al. [2025] conduct a series of high-resolution observations to investigate the importance of vertical water motions induced by meso- and sub-mesoscale flows associated with these mesoscale eddies. The results suggest that secondary circulation caused by eddy flows near fronts along the East Australian Current induces the offshore phytoplankton bloom over 100 kilometers. 

Citation: Chapman, C. C., Sloyan, B. M., Schaeffer, A., Suthers, I. M., & Pitt, K. A. (2024). Offshore plankton blooms via mesoscale and sub-mesoscale interactions with a western boundary current. Journal of Geophysical Research: Oceans, 129, e2023JC020547. https://doi.org/10.1029/2023JC020547

—Takeyoshi Nagai, Editor, JGR: Oceans

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.

Extratropical cyclones (or low-pressure systems) traveling along the Kuroshio in East Asia most frequently occur in spring, bringing heavy rain and snowfall in the region. Researchers at the University of Tsukuba unveiled the mechanism underlying the peak observed in the activity of Kuroshio cyclones during spring using four-dimensional atmospheric data spanning several decades. Their findings revealed that air over Eurasia warmed from winter to spring intensified the low-level jet stream around the East China Sea, increasing the occurrence probability of low-pressure systems during spring.

Extreme rainfall events can cause devastating floods, landslides, and widespread damage, yet predicting them remains a major challenge. While scientists often study how often and how intensely it rains, the duration of rainfall is just as critical in assessing its impact. However, research on long-lasting extreme rainfall has been limited—until now.

Publication date: 1 June 2025

Source: Earth and Planetary Science Letters, Volume 659

Author(s):

Publication date: 1 June 2025

Source: Earth and Planetary Science Letters, Volume 659

Author(s): Yves Marrocchi, Tahar Hammouda, Maud Boyet, Guillaume Avice, Alessandro Morbidelli

Publication date: 1 June 2025

Source: Earth and Planetary Science Letters, Volume 659

Author(s): A.R. Nordsvan, K.W. Bauer, C.L. Colleps, R.N. Mitchell, N.R. McKenzie

Publication date: 1 June 2025

Source: Earth and Planetary Science Letters, Volume 659

Author(s): Dehan Shen, Shijie Li, Shaolin Li, Yingkui Xu, Yang Li, Mingbao Li, Deliang Wang, Ronghua Pang, Yuwei Zhang, Zhipeng Han