EOS

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

La integración de energía renovable en redes eléctricas a las escalas necesarias para mitigar las crecientes concentraciones de gases de efecto invernadero en la atmósfera y el calentamiento global requiere un almacenamiento confiable, y en grandes cantidades. Esto se debe a la variabilidad del viento y la radiación solar incidente, que suministran la mayor parte de esta energía. Las cada vez más avanzadas baterías son el medio predilecto para lograr este almacenamiento.

Entra el litio, cuyo peso ligero, alto potencial electroquímico y el alto cociente de carga a peso lo hacen deseable para su uso en baterías para todo, desde aparatos electrónicos hasta vehículos y redes eléctricas. La demanda de este tipo de baterías ha impulsado un crecimiento acelerado de la producción mundial de litio: se estima que en 2023 se produjeron 180,000 toneladas, en comparación con unas 35,000 en la década anterior.

Sin embargo, la comunidad hidrológica ha prestado poca atención a muchas interrogantes científicas relacionadas al agua en la MLL y la CQ.

El litio se extrae principalmente de las rocas del mineral espodumena, por ejemplo, en Australia, y de la salmuera de salares en regiones como la “Media Luna de Litio” (MLL) en Sudamérica y la Cuenca de Qaidam (CQ) en China. En estas dos zonas, tanto los residentes locales como la prensa, las agencias gubernamentales y las organizaciones no gubernamentales están prestando cada vez más atención a los problemas hídricos y ambientales relacionados con la extracción de salmuera, y las tensiones con las empresas mineras son cada vez más públicas.

Sin embargo, la comunidad hidrológica ha prestado poca atención a muchas interrogantes científicas relacionadas al agua en la MLL y la CQ. Estas preguntas involucran la conectividad natural y el transporte de los recursos hídricos regionales, y cómo el clima y las operaciones mineras afectan su cantidad y calidad. Hidrólogos, hidrometeorólogos e hidrogeólogos deberían trabajar para responder a estas preguntas y ofrecer una visión más integral de cómo se puede lograr una extracción de salmuera más sostenible mediante tecnologías y métodos de estudio consolidados, esto consultando con residentes, gobiernos e industrias de extracción de minerales.

Litio de una media luna y un cuenco

La MLL y la CQ, que respectivamente son la segunda y la primera mesetas más grandes del mundo, son cuencas endorreicas áridas, lo que significa que están hidrológicamente desconectadas del océano. Existen numerosos lagos salados en ambas regiones, con superficies que varían de 1 a 10,000 kilómetros cuadrados en la MLL y de menos de 1 a más de 600 kilómetros cuadrados en la CQ. Los lagos obtienen agua dulce del flujo fluvial proveniente de los glaciares, la nieve y la lluvia en las montañas adyacentes, así como del agua subterránea alimentada por el flujo de ríos y la precipitación. La principal vía de salida del agua de estas cuencas es la evapotranspiración, que con el tiempo concentra las sales minerales en depósitos en el fondo de la cuenca, lo que posibilita la extracción de salmuera.

Las fuentes de litio provenientes de salmueras en la región fronteriza entre Bolivia, Argentina y Chile, en la meseta andina (Figura 1, izquierda), la denominada Media Luna de Litio (un área más pequeña dentro de la MLL se conoce comúnmente como el Triángulo del Litio), representan aproximadamente el 53 % de las reservas mundiales conocidas de litio [Steinmetz y Salvi, 2021]. Esta región también produce aproximadamente un tercio de los compuestos de litio a nivel mundial.

China, por su parte, posee alrededor del 6.5 % de las reservas conocidas de litio y contribuyó con cerca del 18 % de la producción mundial de compuestos de litio en 2023. Varias operaciones de extracción de salmuera en China se llevan a cabo en la cuenca del Qaidam, en la provincia de Qinghai, en la meseta tibetana septentrional (Figura 1, derecha). En 2023, el 21.2 % de la producción total de carbonato de litio de China provino de la cuenca del Qaidam [Oficina de Estadísticas de Qinghai, 2023].

Fig. 1. Los contornos rojos indican la ubicación geográfica de la Media Luna de Litio (MLL, izquierda) en la meseta andina de Sudamérica y la Cuenca Qaidam de China (CQ, derecha) en la meseta tibetana septentrional. La MLL tiene elevaciones de 2200 a 6800 metros y una superficie de 327 000 kilómetros cuadrados; la CQ tiene elevaciones de 2600 a 6800 metros y una superficie de 279 000 kilómetros cuadrados. Los contornos de ambas cuencas provienen de HydroBASINS. Haga clic en la imagen para ampliarla. Crédito: datos cartográficos de Google Earth, SIO, NOAA, Marina de los EE. UU., NGA, GEBCO, Landsat, Copernicus, IBCAO

La CQ produce no solo compuestos de litio, sino también potasa, combustibles fósiles, cloruro de sodio y otros recursos que contribuyen significativamente a la industria y la agricultura de China. Por ejemplo, la potasa producida en la QB en 2023 representó el 69.4 % de la producción total de este recurso en China y el 6.5 % de la producción mundial (cifras calculadas con base en datos de la Oficina de Estadística de Qinghai [2023] y del Servicio Geológico de Estados Unidos).

Aumento de demanda en medio de condiciones cambiantes

Las regiones de la MLL y la CQ reciben cantidades similares de precipitación, con promedios anuales totales de aproximadamente 170 a 180 milímetros, que caen principalmente en sus respectivos veranos. Sin embargo, mientras que la precipitación disminuye ligeramente en MLL, esta aumenta gradualmente en CQ (Figura 2). La MLL también es más cálida y húmeda en promedio y presenta una evapotranspiración potencial mucho mayor que CQ; sin embargo, las temperaturas en ambas regiones están aumentando.

Se predice que el almacenamiento de agua disminuirá debido a que el calentamiento podría reducir los glaciares y la nieve en ambas regiones, y estos cambios podrían aumentar la variabilidad de los caudales fluviales y alterar los regímenes de caudal.

Se proyecta que estas tendencias continuarán en las próximas décadas, y los cambios climáticos tendrán consecuencias para los recursos hídricos. Se predice que el almacenamiento de agua disminuirá debido a que el calentamiento podría reducir los glaciares y la nieve en ambas regiones, y estos cambios podrían aumentar la variabilidad de los caudales fluviales y alterar los regímenes de caudal. Junto con el calentamiento, la reducción en precipitación exacerbará las condiciones de sequía en la MLL. En la CQ, el aumento de la precipitación y el derretimiento de los glaciares y la nieve probablemente causarán más eventos extremos compuestos similares a las inundaciones catastróficas que ocurrieron en la región en 2010 [Ma y Xu, 2011] y 2022. Estas inundaciones dañaron campos de salmuera, presas e infraestructura y causaron pérdidas económicas superiores a los 10 millones de dólares.

Mientras tanto, la industria de la extracción de salmuera ha experimentado un auge en las últimas décadas en ambas regiones. Se prevé que la explotación de recursos, especialmente de litio, se intensifique en el futuro próximo, siguiendo la tendencia reciente.

Para extraer los materiales deseados, los mineros perforan pozos en los salares y bombean salmuera rica en minerales a la superficie. La salmuera se deja evaporar durante unos 12 a 18 meses, durante los cuales se evapora aproximadamente el 90 % del agua original. El material restante se recolecta y procesa para obtener productos minerales comercializables. Este proceso de bombeo de salmuera y aumento de la evaporación en la superficie altera los ciclos hidrológicos locales naturales. Además, se necesita agua dulce durante toda la etapa de procesamiento para purificar los compuestos químicos.

Fig. 2. Las gráficas muestran la precipitación anual y la precipitación promedio mensual (Pre), la evapotranspiración potencial (PET), la presión de vapor (VAP) y la temperatura del aire (T) en la MLL y la CQ de 1960 a 2022. Las estrellas indican la significancia de las tendencias con un valor de p < 0.05. Los datos provienen de la Unidad de Investigación Climática TS, versión 4.07. Haga clic en la imagen para verla más grande.

En los últimos años, se han reportado casos que vinculan la extracción de salmuera con la generación de residuos, la contaminación del agua y el suelo, la alteración del paisaje y la degradación de la flora y la fauna, así como con importantes problemas relacionados con la cantidad y la calidad del agua. También se han reportado conflictos y tensiones entre la población local y las empresas mineras en la meseta tibetana y la MLL, relacionados con la reducción de los recursos hídricos y la contaminación de las aguas subterráneas y los caudales fluviales [Marconi et al., 2022; Giglio, 2021].

Los estudios también documentan los efectos en los ecosistemas. Por ejemplo, la reducción de algunas poblaciones de flamencos andinos se correlaciona con un nivel freático más bajo [Gutiérrez et al., 2022], y las poblaciones de cianobacterias que alimentan a los flamencos andinos están disminuyendo en lagunas cercanas al Salar de Atacama en Chile debido al consumo de agua y la contaminación causada por la extracción de litio [Gutiérrez et al., 2018].

La cantidad de agua utilizada en las operaciones de extracción de salmuera puede variar según el clima, las concentraciones minerales y la tecnología empleada, pero para la MLL, los investigadores han estimado que se necesitan entre 100,000 y 800,000 litros de agua por tonelada métrica de litio extraído [Vera et al., 2023]. No existe una estimación similar para la CQ, pero la próspera industria minera en la zona también está aumentando la demanda de agua.

En el sur de la QC, el uso industrial de agua aumentó de 90 millones de metros cúbicos en 2000 a 383 millones de metros cúbicos en 2019, lo que representa el 10.2% y el 40.8%, respectivamente, del consumo total de agua en la región en esos años [Han et al., 2023]. En 2016, se construyeron instalaciones de desviación de agua y canales para transportar agua desde subcuencas cercanas a campos de salmuera y ciudades para satisfacer la creciente demanda. En diciembre de 2023, tres fábricas importantes de extracción de salmuera en la CQ incumplieron sus cuotas de uso de agua al bombear ilegalmente agua subterránea y extraer agua de humedales y lagos protegidos para satisfacer sus demandas de producción. Estas acciones fueron criticadas públicamente por el Ministerio de Ecología y Medio Ambiente de China, que ordenó a las fábricas que dejaran de bombear agua ilegalmente.

Esclareciendo la hidrología en torno a la minería de salmuera

Tenemos un conocimiento limitado del papel de los salares en estos ciclos o de cómo la expansión de las operaciones de extracción de salmuera para satisfacer la demanda de litio podría alterar este papel.

Al igual que el océano y otras reservas de agua debajo, sobre y por encima de la superficie terrestre, los salares del mundo tienen un rol en sus ciclos hidrológicos regionales. Sin embargo, tenemos un conocimiento limitado del papel de los salares en estos ciclos o de cómo la expansión de las operaciones de extracción de salmuera para satisfacer la demanda de litio podría alterar este papel.

Los hidrólogos enfrentan varias preguntas generales: ¿Cómo y en qué medida afecta la extracción de salmuera a los diversos reservorios y flujos (p. ej., recarga de aguas subterráneas, desvío de caudales, evaporación) del ciclo hidrológico regional? ¿Cómo llega la escorrentía superficial de las montañas circundantes a los depósitos de agua subterránea? ¿Cómo se conectan estos depósitos bajo las cuencas desérticas donde se forman los lagos de salmuera? ¿Cuáles son las edades y la composición química de estas aguas subterráneas? Abordar estas preguntas permitirá conocer mejor la cantidad y la calidad de los recursos hídricos disponibles, lo que a su vez ayudará a los responsables de la toma de decisiones a asignar el agua de forma justa a los diferentes sectores y a monitorear y proteger la calidad del agua durante la extracción de salmuera.

Estanques de evaporación en el lecho seco del lago West Taijinai’er en la CQ observados en septiembre de 2023. Crédito: Lan Cuo

Además, debido a que la MLL y la CQ están experimentando un calentamiento similar pero diferentes tendencias de precipitación, y sus respectivos ciclos hídricos regionales pueden, por lo tanto, verse afectados de manera diferente por el cambio climático, los hidrólogos deben explorar preguntas relacionadas con estas diferencias. ¿Cómo responden los glaciares y la nieve en estas regiones al calentamiento emparejado con más (o menos) precipitación? ¿Y cómo responden los regímenes de caudal (que comprenden las magnitudes, los tiempos, las frecuencias y las duraciones de los caudales altos y bajos) a los cambios en los glaciares, la nieve y la precipitación? ¿Qué mecanismos controlan los eventos extremos como sequías e inundaciones en estas regiones? Responder a estas preguntas esclarecerá cómo el cambio climático está afectando los escasos recursos hídricos en la MLL y la CQ y puede informar los esfuerzos de mitigación para conservar estos recursos.

Investigar todas estas interrogantes requiere diversos enfoques. Se necesitan mediciones in situ de precipitación, evaporación, glaciares y nieve, así como de aguas subterráneas, lagos, ríos y suelos, para determinar la disponibilidad y calidad de los recursos hídricos en ubicaciones específicas de la MLL y la CQ. Los análisis con isótopos estables y trazadores pueden ayudar a determinar las fuentes y la edad del agua sobre y bajo la superficie terrestre. Las observaciones satelitales de cómo cambian las variables del paisaje, como la desertificación, la superficie lacustre, los glaciares y la nieve, la humedad del suelo y la vegetación, ayudarán a rastrear los efectos del cambio climático y la extracción de salmuera en los recursos hídricos y los ecosistemas. También necesitaremos estudios de modelización hidrogeológica para comprender la hidrología superficial, el almacenamiento y el movimiento de las aguas subterráneas, y cómo se ven afectados por la escorrentía superficial en la MLL y la CQ (se requieren mediciones in situ para validar los estudios satelitales y de modelización).

Además, se debe fomentar la colaboración entre investigadores de ambas regiones para permitir comparaciones detalladas y esclarecer las diferencias y los puntos en común en los problemas hídricos de cada una. Estas colaboraciones también facilitarían el intercambio de mejores prácticas de investigación y posibles soluciones políticas con respecto a la extracción de salmuera y los recursos hídricos.

Involucrar a todas las partes interesadas para obtener mejores resultados

La extracción de salmuera será sostenible sólo cuando las operaciones, desde su inicio hasta su fin, utilicen el agua de manera eficiente, minimicen el daño al medio ambiente, los ecosistemas y las comunidades, y compensen los daños.

Los recursos hídricos en la MLL y la CQ ya se encuentran bajo tensión debido a su ubicación en medio de los desiertos más altos del mundo y a las cambiantes condiciones climáticas. La extracción de salmuera para abastecer de litio y otras materias primas a la transición a energías renovables podría agravar esta tensión. Esta extracción sólo será sostenible cuando las operaciones, desde su inicio hasta su fin, utilicen el agua de manera eficiente; minimicen los daños al medio ambiente, los ecosistemas y las comunidades; y compensen los daños cuando estos ocurran.

La combinación de múltiples enfoques científicos para estudiar la hidrología regional generará un conocimiento holístico e integral de la cantidad y la calidad del agua en estas áreas. Sin embargo, para apoyar la sostenibilidad de la extracción de salmuera y la gestión de los recursos hídricos en la MLL y la CQ, los científicos deben compartir la información y las respuestas obtenidas de estos enfoques con las agencias gubernamentales pertinentes, las empresas mineras y las comunidades locales a través de informes de investigación, conferencias y asambleas públicas que reúnan a estos grupos.

La participación de los miembros de la comunidad contribuirá especialmente a revelar no solo los efectos en la hidrología y los ecosistemas, sino también el costo humano de las actividades mineras y el cambio climático. Y una mejor comunicación entre estos grupos ayudará a los legisladores y reguladores a crear y hacer cumplir normas para regir las operaciones mineras responsables, al tiempo que mitigan los impactos negativos y satisfacen las necesidades de la comunidad.

Referencias

Giglio, E. (2021), Extractivism and its socio-environmental impact in South America: Overview of the “lithium triangle,” Am. Crítica, 5(1), 47–53, https://doi.org/10.13125/americacritica/4926.

Gutiérrez, J. S., J. G. Navedo, and A. Soriano-Redondo (2018), Chilean Atacama site imperilled by lithium mining, Nature, 557, 492, https://doi.org/10.1038/d41586-018-05233-7.

Gutiérrez, J. S., et al. (2022), Climate change and lithium mining influence flamingo abundance in the Lithium Triangle, Proc. R. Soc. B, 289, 20212388, https://doi.org/10.1098/rspb.2021.2388.

Han, J., et al. (2023), The potential analysis of rain-flood resources in the Golmud river catchment based on climate change and human interventions, Qaidam basin [in Chinese], J. Salt Lake Res., 31(4), 30–38.

Ma, S., and L. Xu (2011), 2010 Golmud River flooding analysis, Qinghai Sci. Technol., 1, 38–41.

Marconi, P., F. Arengo, and A. Clark (2022), The arid Andean plateau waterscapes and the lithium triangle: Flamingos as flagships for conservation of high-altitude wetlands under pressure from mining development, Wetlands Ecol. Manage., 30, 827–852, https://doi.org/10.1007/s11273-022-09872-6.

Qinghai Bureau of Statistics (2023), Statistics of national economy and social development in 2023 [in Chinese], m.yicai.com/news/102000260.html.

Steinmetz, R. L. L., and S. Salvi (2021), Brine grades in Andean salars: When basin size matters—A review of the Lithium Triangle, Earth Sci. Rev., 217, 103615, https://doi.org/10.1016/j.earscirev.2021.103615.

Vera, M. L., et al. (2023), Environmental impact of direct lithium extraction from brines, Nat. Rev. Earth Environ., 4, 149–165, https://doi.org/10.1038/s43017-022-00387-5.

Datos de autora

Lan Cuo (lancuo@itpcas.ac.cn), State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Pekín; también en la University of Chinese Academy of Sciences, Pekín

This translation by Nelmary Rodriguez Sepulveda was made possible by a partnership with Planeteando y GeoLatinas. Esta traducción fue posible gracias a una asociación con Planeteando and GeoLatinas.

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 © 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: Global Biogeochemical Cycles

Marine life plays a pivotal role in Earth’s carbon cycle. Phytoplankton at the base of the aquatic food web take up carbon dioxide from the atmosphere, convert it to organic carbon, and move it around as they become food for other organisms. Much of this carbon eventually returns to the atmosphere, but some ends up sequestered in the deep ocean via a process called carbon export.

Quantifying carbon export to the deep ocean is critical for understanding changes in Earth’s climate. Measurements in the Southern Ocean, a key region for global ocean circulation and a substantial carbon sink, are especially important but have been sparse, particularly in areas with sea ice that are difficult to access.

To address that gap, Liniger et al. used data from 212 autonomous, floating instruments known as Biogeochemical-Argo (BGC-Argo) floats to estimate carbon export across the Southern Ocean basin. These floats roam the upper 2,000 meters of the ocean, can travel beneath sea ice, and are equipped with sensors that measure physical and biogeochemical properties of seawater.

Though prior studies have used BGC-Argo data to estimate Southern Ocean carbon export, most focused on narrow regions or timescales and excluded sea ice–covered areas. The new analysis uses data collected between 2014 and 2022 by floats scattered across the entire ocean basin, including under sea ice. After developing a novel method to calculate carbon export using the floats’ measurements of sinking particulate organic carbon and dissolved oxygen change over time, the researchers estimated that about 2.69 billion tons of carbon sink to the deep sea each year in the Southern Ocean.

Their findings also suggest that carbon export varies significantly in different parts of the Southern Ocean, with only about 8% occurring in seasonally ice-covered areas. But the researchers say more investigation is needed to clarify the role of the highly active ecosystems in the sea ice zone, especially as climate change drives shifts in sea ice dynamics. (Global Biogeochemical Cycles, https://doi.org/10.1029/2024GB008193, 2025)

—Sarah Stanley, Science Writer

Citation: Stanley, S. (2025), Robotic floats quantify sinking carbon in the Southern Ocean, Eos, 106, https://doi.org/10.1029/2025EO250193. Published on 27 May 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.

Smaller rockfalls have reduced the risk of a major rock slope collapse above Blatten, but attention has shifted to the Birch Glacier, which is now moving at 10 metres per day.

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

Over the last few days, the situation above Blatten in Switzerland has developed considerably. The good news is that the rock slope failure has continued to occur as a series of smaller rockfalls, rather than a single very large collapse. This has limited the runout distance of the debris, sparing, at least so far, Blatten itself.

The webcam has been difficult to use due to the cloudy weather, but the view this morning (27 May 2025) shows that the slope has evolved considerably:-

Webcam image from 27 May 2025 showing the deforming slope at Blatten in Switzerland. Image from Bergfex.

Throughout this crisis, Melaine Le Roy has provided excellent updates via his Bluesky account. Embedding Bluesky posts on Wordpress is very hit and miss, but hopefully this will work. If not, please follow the links.

Yesterday, Melaine posted an update provided by Alban Brigger in the regular press conference about the Blatten event:-

#Blatten Press conference Alban Brigger, -glacier front velocity is 2.5-3 m/day. ‘We do not expect an exponential acceleration, as we feared before.’-the amount of debris deposited on the glacier is 3.5 Mm3 = 9 M t. Up to 80 m thick!1/

On a summer day not long ago, 10 people gathered to eat cheese in the name of science. They nibbled on small rounds of Cantal, a firm cow’s milk cheese historically produced in south central France, and evaluated more than 25 attributes spanning color, odor, taste, aroma, and texture. The tasting was just one component of a larger study on the effects of shifting cows’ diets from grass to corn because of industrialization and climate change. The new findings highlight the importance of maintaining at least some grass in cows’ diets.

“Their physiology and digestive tracts are made to digest grass.”

Cows, with their four stomach pouches, are evolutionarily primed to consume grass and extract all the nutrients possible from that roughage. “Cows are herbivores,” said Elisa Manzocchi, a dairy researcher at Agroscope in Posieux, Switzerland, who was not involved in the research. (Agroscope is a Swiss governmental organization devoted to agricultural research.) “Their physiology and digestive tracts are made to digest grass.”

But bovines around the world are increasingly being fed a corn-based diet as industrial-scale farming proliferates—it’s often easier, more efficient, and more scalable to feed cows from a trough rather than allow them to forage in a pasture.

Climate change is also driving that shift. Even in regions that have long turned cows out to green pastures, farmers are facing summertime grass shortages due to droughts. That’s true in Marcenat, the site of an experimental farm run by the National Research Institute for Agriculture, Food and Environment (INRAE), said Matthieu Bouchon, an animal husbandry scientist there. It’s hotter in the summer than it used to be, but there’s still a lot of spring rainfall, he said. “The conditions are perfect for corn cultivation.”

Seeing cornfields in Marcenat, a mountainous region in south central France at an elevation of 1,000 meters, is jarring, Bouchon said. “It’s not something we’re used to.”

Bouchon and his colleagues at INRAE, led by microbiologist Céline Delbès, recently investigated how changing a cow’s diet has a slew of trickle-down effects on the quantity, quality, nutritional value, and flavor of its milk and resultant cheese. Earlier work compared outcomes of grass- and corn-fed diets in cows, Manzocchi said, but this investigation is particularly thorough. “It’s one of the first studies where they looked at many parameters.”

Soil to Grass to Cow to Milk to Cheese

The team focused on 40 Prim’Holstein and Montbéliarde cows, dividing them into two groups: one fed a largely grass-based diet and the other fed a corn-based diet with some access to pasture grass. After 2 months, half of the cows in the first group were switched to a less grass-based diet, and half of the cows in the second group were entirely denied access to pasture grass. The result was a cohort of four bovine groups that for nearly three more months, ate roughly 75%, 50%, 25%, and 0% grazed grass, respectively.

Throughout the experiment, Delbès and her collaborators collected milk samples two times per week (the cows were milked twice per day), soil samples from the pasture grass, and even swabs from the cows’ udders. The goal was to better understand how a dietary shift induced by climate change translates into changes in the attributes of a herd’s milk and, ultimately, cheese. “There were a lot of things in this experiment,” Bouchon said.

The researchers enlisted the help of a cheese-making facility near the farm to produce small rounds of Cantal cheese, each weighing about half a kilogram, using milk from the cows in each of the four groups. The cheeses were aged for 9 weeks before being served to panelists trained in tasting Cantal-type cheeses.

Preserve the Grass

Consistent with previous findings, the researchers found that cheese made from milk from cows fed primarily grass were more flavorful and had higher levels of certain fatty acids compared with cheeses produced from cows primarily fed corn. However, cows fed diets with a higher proportion of grass also yielded less milk relative to the amount of food they consumed, the team noted.

Overall, Delbès and her collaborators found that the shift from a diet of 25% grazed grass to one of 0% grazed grass was more detrimental to a cheese’s nutritional and sensory qualities than the shift from a 75% grazed grass diet to a 50% grazed grass diet.

“It’s surprising that just a quarter of the diet can do so much [to affect] the sensory quality of the cheese.”

The finding suggests that maintaining at least a modicum of fresh grass is critical to ensuring quality cheese, Delbès said.

“It’s surprising that just a quarter of the diet can do so much [to affect] the sensory quality of the cheese,” Manzocchi said. But perhaps that finding should be reassuring to traditional cheese producers who might no longer be able to feed their herds a largely grass-based diet, she added. “Maybe it’s good news.”

Delbès and her team aren’t yet finished with their Prim’Holstein and Montbéliarde herds. Future work will focus on examining how microbes present in the soil and bedding areas of the cows, for example, are correlated with microbes present in the human gut after cheese is consumed.

—Katherine Kornei (@KatherineKornei), Science Writer

28 May 2025: This story has been updated to correct the location of the experimental farm.

Citation: Kornei, K. (2025), Cheese in the time of industrial farming and climate change, Eos, 106, https://doi.org/10.1029/2025EO250198. Published on 23 May 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: Geophysical Research Letters

Soil moisture is a key regulator of temperature and humidity, one that’s positioned to be affected substantially by climate change. But despite the importance of soil moisture, efforts to model it involve dozens of poorly constrained parameters, and different models tend to disagree about how soil moisture levels will change in a warming world.

Gallagher and McColl took a “radically simpler” approach and modeled soil moisture solely in terms of precipitation and net surface radiation. The model worked well when tested using both fifth-generation European Centre for Medium-Range Weather Forecasts atmospheric reanalysis (ERA5) and Coupled Model Intercomparison Project Phase 6 (CMIP6) climate datasets.

That’s surprising, the researchers say, because the simple model excludes measurements that much of the recent literature has focused on: vapor pressure deficit (the difference between the amount of moisture the air has the capacity to hold and the amount it is actually holding) and atmospheric carbon dioxide (CO2) levels. Both are expected to rise alongside greenhouse gas emissions.

The researchers suggest their model still works well because vapor pressure deficit is a poor measure of atmospheric demand for water; net surface radiation, which is included in the model, is a better measure. In regard to CO2, the researchers say that some prior studies have overestimated the role of the gas.

The simple model offers potential answers to two fundamental questions about soil moisture: (1) Why does soil moisture follow a W-shaped longitudinal profile, with high moisture at the equator and poles and low moisture in between, and (2) why does soil moisture increase with warmer temperatures in some locations but decrease in others?

The W-shaped profile may be caused by a combination of precipitation rates and radiation intensity. High precipitation near the equator dominates the model and causes high soil moisture. The midlatitudes and the poles both see moderate levels of precipitation. But the midlatitudes receive more intense radiation than the poles, which leads to comparatively dryer midlatitude soils.

As for the second question, the researchers suggest warming may have varying effects on soil moisture because warming can come with both increased precipitation, which raises soil moisture, and increased net surface radiation, which lowers soil moisture. These two variables balance each other out to different degrees at different locations, meaning that warming sometimes raises soil moisture and sometimes lowers it. (Geophysical Research Letters, https://doi.org/10.1029/2025GL115044, 2025)

—Saima May Sidik (@saimamay.bsky.social), Science Writer

Citation: Sidik, S. M. (2025), Simplicity may be the key to understanding soil moisture, Eos, 106, https://doi.org/10.1029/2025EO250197. Published on 23 May 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 upcoming Atlantic hurricane season will likely have above-normal activity, according to the annual outlook produced by NOAA.

NOAA issues an Atlantic hurricane season outlook each May, using computer models that consider current climate and ocean conditions.

“Everything is in place for an above-average season.”

The agency estimates that this year’s Atlantic hurricane season, which runs from 1 June to 30 November, will have up to 19 named storms and up to 10 hurricanes. Three to five of those hurricanes are projected to reach major hurricane strength (categories 3, 4, and 5).

Between 1991 and 2020, the Atlantic hurricane season featured seven hurricanes on average.

The report predicts a 60% chance of an above-normal season, a 30% chance of a near-normal season, and a 10% chance of a below-normal season.

“Everything is in place for an above-average season,” said Ken Graham, director of the National Weather Service, at a press conference held in Jefferson Parish, La. NOAA selected Jefferson Parish as the location for the announcement to commemorate the 20-year anniversary of Hurricane Katrina.

Above-average Atlantic Ocean temperatures will fuel an above-average Atlantic hurricane season, according to a NOAA report. Credit: NOAA NWS

The above-average activity forecasted by NOAA will be fueled by above-average temperatures in the Atlantic and Caribbean Sea, forecasts for weak wind conditions, and the potential for higher activity of this year’s West African Monsoon.

The NOAA predictions align with predictions from other institutions, including Colorado State University’s (CSU) Tropical Weather and Climate Research Group. CSU’s forecast predicted 9 hurricanes and 17 named storms for the 2025 season, with 4 of those storms predicted to reach major hurricane strength.

Scientists expect the El Niño–Southern Oscillation (ENSO), a climate phenomenon that affects how heat is stored in the oceans, to remain in a neutral condition or transition to La Niña conditions this summer. Such conditions lead to decreased wind shear, which slightly favors hurricane formation.

In 2024, El Niño conditions, along with human-caused climate change, fueled a spike in ocean temperatures that caused a destructive Atlantic hurricane season. Warming oceans fuel stronger hurricanes that bring more heavy rainfall and higher storm surge when they make landfall.

“It takes only one storm near you to make this an active season for you.”

The odds of El Niño developing this year as the hurricane season peaks are low—less than 15%, according to the latest NOAA prediction. While El Niño conditions tend to increase ocean temperatures, El Niño also creates wind shear that breaks up weather patterns, hindering hurricane intensification. If El Niño conditions do return by the fall, the likelihood of hurricane formation could drop. CSU plans to release an updated forecast on 11 June.

At the press conference, NOAA officials asked those in hurricane-prone areas to prepare for the busy season. “A community that is more informed and prepared will have a greater opportunity to rebound quickly from weather and climate related events,” said Cynthia Lee Sheng, president of Jefferson Parish.

Each year, the World Meteorological Organization selects a list of names for the season’s tropical storms. Credit: NOAA NWS

“It takes only one storm near you to make this an active season for you,” said Michael Bell, a meteorologist at CSU and author of the CSU outlook, in a statement.

The above-average season coincides with unprecedented staffing shortages due to layoffs and staff buyouts at NOAA and its National Weather Service (NWS), which issues hurricane and flood warnings and provides critical emergency information during storms. In a 2 May open letter, five former NWS directors said the agency “will have an impossible task” trying to continue its current level of services amid staff and funding cuts.

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

Citation: van Deelen, G. (2025), Busy hurricane season expected in 2025, Eos, 106, https://doi.org/10.1029/2025EO250200. Published on 22 May 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
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Ammonia released from penguin poop helps produce cloud-seeding aerosols in Antarctica, which can affect local climate by increasing cloud formation. The discovery came when scientists measured air downwind of two colonies of Adélie penguins on the tip of the Antarctic Peninsula.

Penguin poop emitted 100–1,000 times baseline levels of ammonia. New aerosol particles formed when that ammonia mixed with sulfur compounds from marine phytoplankton. The research was published in Communications Earth & Environment.

“This shows a deep connection between the natural ecosystem emissions and atmospheric processes, where emissions from both local seabird and penguin colonies and marine microbiology have a synergistic role that can impact clouds and climate,” said Matthew Boyer, a doctoral student in atmospheric science at the University of Helsinki in Finland and lead author of the study.

Strong Whiffs of Ammonia

Although only trace amounts of ammonia exist in Earth’s atmosphere, scientists have found that when it mixes with certain sulfur compounds it creates ultrafine particles (<0.1 micrometer in size). Those aerosols can grow into cloud condensation nuclei.

“Aerosol particles are necessary for cloud formation; liquid water will not condense to form cloud droplets without the presence of aerosol particles,” Boyer explained.

The presence of these aerosols is especially important in pristine environments such as Antarctica that have low background levels of cloud-forming particles.

“The new particle formation process doesn’t strictly need ammonia to proceed, but ammonia boosts the rate of the process considerably—up to 1,000 times faster,” Boyer said. Gases emitted from natural sources such as penguins and the ocean are an important source of aerosols in the region, he added.

But the extremely low concentrations of gaseous ammonia, combined with the remoteness of Antarctica, have made understanding this cloud formation pathway challenging.

To tackle this problem, the researchers set up atmospheric samplers on the ground near Argentina’s Marambio Station, located on Seymour Island near the northernmost tip of the Antarctic Peninsula. Two large colonies of Adélie penguins nested a few kilometers away, one with about 30,000 breeding pairs and another with roughly 15,000 penguin pairs, as well as 800 cormorant pairs.

Researchers put sensors near the main buildings at Marambio Station on Seymour Island. Credit: Lauriane Quéléver

From 10 January to 20 March 2023 (during austral summer), the team measured concentrations of ammonia, fine aerosol particles, and larger cloud condensation nuclei, as well as relative abundance of certain elements, cloud droplet distribution, and other atmospheric properties. By late February, the penguins left their breeding grounds and traveled to their wintering site, enabling the researchers to analyze the atmosphere with and without the birds present.

When wind blew air from the nesting grounds to the monitoring station, the team found that the penguin colonies emitted up to 13.5 parts per billion of ammonia, more than 1,000 times more than background levels without poop. However, when winds blew in from the sea, the Southern Ocean was a “negligible” source of ammonia.

“The footprint of ammonia emissions from penguins may cover more area of coastal Antarctica than indicated by the location of their colonies alone.”

Even after the penguins migrated, the poop they left behind continued to elevate ammonia to 100 times higher than background levels, which was the most surprising discovery for Boyer.

“This means that the footprint of ammonia emissions from penguins may cover more area of coastal Antarctica than indicated by the location of their colonies alone,” he said.

The team found that 30 times more aerosol particles formed when gaseous ammonia mixed with sulfuric gases released by marine phytoplankton. When that combination then mixed with dimethylamine gas, also emitted by penguin poop, aerosol formation increased 10,000-fold.

Gaseous ammonia lasts only a few hours in the atmosphere, but the aerosol particles it creates can survive for several days. Under the right wind conditions, those particles could travel out over the Southern Ocean and generate clouds where cloud condensation nuclei sources are limited.

Climate change threatens the survival of Adélie penguins, but the penguins also help shape their local atmosphere and climate. Credit: Matthew Boyer

The new results align with past research that examined the impact of Arctic seabirds on atmosphere and climate. They also agree with past laboratory and modeling studies of Antarctic cloud formation, which have been considered more reliable in the past than in situ measurements.

“Measuring ammonia on its own under normal circumstances can be tricky,” said Greg Wentworth, an atmospheric scientist with the government of Alberta in Canada who was not involved with the new research. “To do all the sophisticated measurements required to tease apart the details of new particle formation is remarkable, especially since they did this at the ends of the Earth!”

Penguin Feedback Loops

“How remarkable is it that emissions from penguin poop and phytoplankton can kick-start chemistry in the atmosphere that can alter clouds and affect climate?”

“This study provides the most compelling evidence to date that ammonia and sulfur compounds…are an important source of cloud condensation nuclei during summertime in Antarctica,” Wentworth added. “How remarkable is it that emissions from penguin poop and phytoplankton can kick-start chemistry in the atmosphere that can alter clouds and affect climate?”

The polar regions are experiencing dangerous levels of warming, and more cloud cover can help cool things down…sometimes. Higher concentrations of aerosol particles tend to create thicker, low-atmosphere clouds that are more reflective and can cool the surface, Boyer said. Thinner clouds high in the atmosphere tend to trap heat and warm the surface.

Understanding whether seabirds generate aerosols at a consistent, high-enough rate to cool local climate would require more atmospheric monitoring and climate modeling, he added.

A connection between penguins and their environment means that when one is threatened, both feel the impacts. As climate change warms the polar regions and endangers the species that live there, the loss of those species could reduce cloud cover and further accelerate warming.

“It’s important to understand how ecosystems, especially sensitive ones in remote regions, will respond to climate change,” Wentworth said. “It’s doubly important to understand those changes when components of those ecosystems also impact climate change.”

“The more we understand about specific processes that impact ecosystems and climate change, the better we can predict and adapt to change,” Wentworth said.

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

Citation: Cartier, K. M. S. (2025), Pungent penguin poop produces polar cloud particles, Eos, 106, https://doi.org/10.1029/2025EO250201. Published on 22 May 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.

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.

Early on 22 May, the U.S. House of Representatives passed a massive GOP-backed bill that seeks to push forward President Trump’s domestic policy agenda. Within the bill’s 1,082 pages are sweeping repeals of regulations that defend the environment, mitigate climate change, and protect public health.

 
Related

•  Here’s What’s in the GOP Megabill that’s Just Passed the House
•  House Republicans Strike a Bigger Blow Against Democrats’ Clean Energy Tax Credits
•  Get Involved: AGU Science Policy Action Center
 

In their place, the bill promotes fossil fuel production and burning; scales back safety net programs such as Medicaid and supplemental nutrition and assistance program (SNAP); rescinds funds and blocks plans for natural resource management; reforms student loan lending and repayment; advances aggressive anti-immigration policies; and funds tax cuts for the ultra-wealthy.

Some of the Earth science-related provisions in the bill would:

• Rescind unused funding allocated to maintain facilities for NOAA and the National Marine Sanctuary;
• Bring an earlier end to clean energy tax credits and subsidies provided under the Inflation Reduction Act;
• Repeal rules related to vehicles’ greenhouse gas emissions and vehicle fuel economy standards;
• Rescind Clean Air Act funds related to environmental and climate justice, as well as other funds meant to reduce or regulate greenhouse gas emissions, improve air quality at schools, and require businesses to publicly report their carbon footprints;
• Rescind funds that would have invested in coastal communities to build climate resilience, and that helped U.S. Forest Service and the National Park Service protect federal land;
• Interfere with several states’ plans to manage their own resources, including in Wyoming, Montana, North Dakota, and along the Colorado River;
• Enhance timber production and logging on National Forest Service lands and allow mineral mining in Alaska to move forward.

The bill passed by a 1-vote margin in the House (215-214). It now moves to the Senate, where it is expected to face additional opposition from the Democratic Party and GOP deficit hawks.

—Kimberly M. S. Cartier (@astrokimcartier.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 © 2025. AGU. CC BY-NC-ND 3.0
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Eos is welcoming June (that’s National Ocean Month in the United States) with a rhyming tradition of something old, something new, something borrowed, and something blue.

Our “something old” is the spectacularly upgraded, 60-years-young Alvin, probably the world’s most famous human-occupied deep-sea submersible. Alvin can now dive to 6,500 meters—a full 2,000 meters more than its previous limit—and explore 99% of the seafloor. Read all about it in “An Upgraded Alvin Puts New Ocean Depths Within Reach.”

“Something new” is the two-vehicle fleet of midsize remotely operated vehicles (mROVs) that will join the U.S. Academic Research Fleet. The mROVs will “fill the niche between large, work-class vehicles such as Jason and small vehicles used primarily for observation.”

“Something borrowed” is time on the JOIDES Resolution (JR), the legendary research vessel that retired last year. In this month’s opinion, three early-career researchers share what they learned, from sediment cores to transdisciplinary collaboration, as part of the JR’s final voyage.

Something blue? That’s the deep blue sea, of course. Dive in!

—Caryl-Sue Micalizio, Editor in Chief

Citation: Micalizio, C.-S. (2025), Submerged in science, Eos, 106, https://doi.org/10.1029/2025EO250199. Published on 22 June 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
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Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Solid Earth

Large earthquakes generally nucleate at the base of seismogenic crust, between 10 and 15 kilometers deep, where the interplay between brittle and plastic deformation is complex due to the combined effects of pressure and temperature at these depths. In consequence, how earthquake fractures may nucleate under these conditions remains relatively enigmatic.

Yeo et al. [2025] present evidence of the formation of nanocavities under these conditions from the geological rock record. The studied rocks are ultramylonites, i.e. rocks of ultrafine grainsize, brought back from an outcrop of the Median Tectonic Line, the largest on‐land fault (>1,000 kilometers along strike) of Japan. Ultramylonites generally deform via intracrystalline plasticity and grain boundary sliding. Yet, the ones presented by the authors have also kept records of the formation of nanoscale cavities, formed at the base of seismogenic zone. When the density of these cavities becomes critical, they may coalesce leading to the formation of a ductile fracture, a phenomenon well-known in metallurgy. The authors observe that these ductile fractures, generally filled with secondary hydrous minerals such as chlorite, were ubiquitous along the entire length of the ultramylonite exposure, spanning over 7 kilometers.

Ductile fractures, observed along one the world’s most active shear zone highlight the importance of fracturing due to ductile deformation in the source region of large earthquakes. In such way, nano-scale cavities generated 15 kilometers deep may well be the initial nucleation point of large continental earthquakes.

Citation: Yeo, T., Shigematsu, N., Wallis, S. R., Kobayashi, K., Zhang, C., & Ujiie, K. (2025). Evolution of nanocavities to ductile fractures in crustal-scale faults at the base of the seismogenic zone. Journal of Geophysical Research: Solid Earth, 130, e2024JB029868. https://doi.org/10.1029/2024JB029868

—Alexandre Schubnel, Editor-in-Chief, JGR: Solid Earth

Text © 2025. The authors. CC BY-NC-ND 3.0
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The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.

On 21 May 2025, a family lost their home to a quick clay landslide in Sainte Monique, to the northeast of Montreal in Quebec, Canada.

Radio-Canada Info has posted to Youtube some excellent drone footage of the aftermath of this landslide:-

Meanwhile, The Globe and Mail has a good account of the event:–

“Andre Lemire said he was woken up early Wednesday morning by his partner, who had heard ominous noises outside the farm where they live in Sainte-Monique, Que.

“They left the home, and when he looked back he saw the ground open up, swallowing up the land and his neighbour’s house.

“The path disappeared behind me,” Lemire said in an interview.

“A major landslide swept away a home and part of a road northeast of Montreal at around 6 a.m. Wednesday, leaving a gaping hole in the land but no injuries. The landslide – estimated at 760 metres long and 150 wide – was described by an expert as one of the biggest the province has seen in recent years.”

This is a classic quick clay landslide, a well-known hazard in this part of Canada. The location of the landslide is [46.13890, -72.49700] – this is a Google Earth image of the site:-

Google Earth image of the site of the 21 May 2025 quick clay landslide at Sainte Monique in Canada.

It is interesting that the location is at the apex of the river meander, where erosion is intense. Google Street View shows that this is an area with a low slope angle, which is normal in quick clay landslides:-

Google Street View image of the site of the 21 May 2025 quick clay landslide at Sainte Monique in Canada.

The dramatic nature of landslides of this type can be seen in this still from the Youtube footage:-

A drone image of the site of the 21 May 2025 quick clay landslide at Sainte Monique in Canada. Still from a drobe video posted to Youtube by Radio-Canada Info.

It is likely that this area sits on the Leda Clay, a material that is prone to failures of this type. This landslide is reminiscent of the 10 May 2010 landslide at St Jude, which tragically killed four people. It is fortunate that at Sainte Monique the owners of the house were able to escape.

Thanks to loyal readers George Heah and Maurice Lamontagne for highlighting this event to me.

Return to The Landslide Blog homepage Text © 2023. The authors. CC BY-NC-ND 3.0
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