Feed aggregator

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

The National Institutes of Health (NIH), the world’s largest funder of biomedical research, announced a policy on 1 May banning scientists from directing its funding to international research partners, according to Nature. 

A statement from NIH said the agency would not halt foreign subawards—funding that U.S. researchers direct to international research partners—from existing grants “at this time,” but that by October, it will not renew or issue foreign subawards. Last year, the NIH issued about 3,700 subawards to foreign institutions.

The new policy may affect critical international health research and research with humanitarian applications, such as projects investigating HIV prevention, malaria treatments, maternal health, and cancer. 

 
Related

•  NIH to End Billions of Dollars in Foreign Research Grants
•  NIH Bans New Funding From U.S. Scientists to Partners Abroad
•  NIH Cancels Climate and Health Research Grants 
•  Get Involved: AGU Science Policy Action Center
 

“If you can’t clearly justify why you are doing something overseas, as in it can’t possibly be done anywhere else and it benefits the American people, then the project should be closed down,” wrote Matthew J. Memoli, the principal deputy director of the NIH, in an email obtained by Nature. 

Coordinated international research on disease outbreaks keeps U.S. residents safe, Francis Collins, former director of the NIH, told Nature: “Disease outbreaks that start anywhere in the world can reach our shores in hours.” Halting international investigations into infectious diseases is “short-sighted and self-defeating,” he said.

The move could also delay clinical trials for new medical therapies, which rely on the participation of many subjects with particular illnesses. For a childhood cancer therapy, for example, “it could take decades to complete a trial if you only enroll children in the U.S.,” E. Anders Kolb, chief executive of the Leukemia & Lymphoma Society, told the New York Times. “When we collaborate with our international partners, we can finish these trials much more quickly and get the therapies to children as soon as possible.”

The Trump administration has already terminated hundreds of grants from NIH, targeting projects having to do with Covid-19, misinformation, transgender health, and climate change. One prominent environmental health journal, Environmental Health Perspectives, announced last week it would pause accepting new studies for publication amid uncertainty surrounding its NIH funding. The Trump administration’s proposed budget would cut NIH funding by about 40%, or about $18 billion. 

“These decisions will have tragic consequences,” Collins told Nature. “More children and adults in low-income countries will now lose their lives because of research that didn’t get done.”

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

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org. Text © 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 ocean plays a large role in cycling carbon dioxide in the atmosphere. Determining how much carbon is locked away in the ocean is critical to understanding Earth's changing climate. However, measuring and monitoring oceanographic processes on a massive scale poses a challenge to scientists.

In shallow coastal waters around the world, mud and other fine-grained sediments such as clay and silt form critical blue carbon sinks. Offshore infrastructure such as wind turbines and oil platforms, as well as fishing practices such as bottom trawling, can have major effects on the seafloor. So knowing the locations of these mud-rich sedimentary deposits is key to making coastal management decisions.

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

“Le Léman”, Lake Geneva, is the title and subject of F.-A. Forel’s seminal book series (1892-1904) that examines its catchment, climate, organisms, and solutes such as carbon and organic matter (OM), essentially establishing “limnology” as a holistic freshwater science. At the time, Forel wondered whether it was possible to fully understand the dynamics of organic material in the lake’s water, given that the influencing factors were so complex, and the variation in concentration so small. Today, we have detailed knowledge about the aquatic carbon cycle, but because much of this comes from the study of smaller and organic-rich northern lakes, it is still uncertain what actually applies to lakes of Geneva’s type.

Adding a piece to this longstanding puzzle, White et al. [2025] analyze the spatiotemporal dynamics of organic and inorganic (radio-)carbon dissolved in Lake Geneva and its biggest tributary, the Rhone. Using detailed data on the carbon composition and age, the researchers substantiate that organic carbon (OC) is primarily sourced from the lake’s large inorganic carbon (IC) pool by photosynthesizing plankton, rather than being imported from catchment soils and vegetation.

However, the authors also find exceptions to this rule. Glacial meltwater bears a characteristic signature of old organic matter and young IC that revealed large carbon imports to the lake during the record heat of 2022. Quantitative understanding of such inflows is important for comprehending the functioning of lakes in a warming alpine region. In the future, glaciated catchments will reach “peak water”, after which the receding glaciers contribute less and less to summertime streamflow, potentially exporting from former glaciated/permafrost areas more soil-derived OC, nutrients and also more IC.

These results also coincide with a renewed interest in lakes’ IC dynamics and associated calcite precipitation. During past investigations of terrestrial exports of carbon and energy, hardwater lakes were largely overlooked. Due to the simultaneous CO2 and calcite (CaCO3) formation by plankton (owed to the precipitation stoichiometry), hardwater lakes can become counterintuitive aquatic greenhouse gas sources. Better knowledge about the carbon sinks and sources there, as provided by the authors, consolidates the mechanisms active in similar, numerous and ecologically important peri-alpine lakes. Surely, Forel would approve.

Citation: White, M. E., Mittelbach, B. V. A., Escoffier, N., Rhyner, T. M. Y., Haghipour, N., Janssen, D. J., et al. (2025). Seasonally dynamic dissolved carbon cycling in a large hard water lake. Journal of Geophysical Research: Biogeosciences, 130, e2024JG008645. https://doi.org/10.1029/2024JG008645

—Maximilian Lau, Associate Editor, JGR: Biogeosciences

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.

When does "anomalous weather" become "a new climate"? The moment that variations in a specific climate variable turn into the new normal is termed Time of Emergence (ToE). Scientists from the University of Groningen and the Royal Netherlands Meteorological Institute (KNMI) have developed a method to predict the time of emergence in various Arctic regions, based on warming, wetting, and sea ice melting.

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

Evapotranspiration is a scientific measurement representing the combined sum of evaporation from the soil (or water) surface to the atmosphere and transpiration from plants, where liquid water inside the plant tissue vaporizes and enters the atmosphere, predominately through stomata. This topic cuts across many disciplines and is important to understand as crops are subjected to increasing environmental stress and management practices.

A new article in Reviews of Geophysics explores the effects of changing environments, abiotic stresses, and management practices on cropland evapotranspiration. Here, we asked the lead author to give an overview of evapotranspiration, how scientists measure it, and what questions remain.

Why is it important to study cropland evapotranspiration?

As a key component of water balance in agricultural systems, evapotranspiration represents the ultimate consumption of agricultural water resources.

Evapotranspiration (ETa) is intricately linked to crop physiological activities and closely coupled with carbon cycle processes. As a key component of water balance in agricultural systems, evapotranspiration represents the ultimate consumption of agricultural water resources. Moreover, variation of regional cropland evapotranspiration reflects the changes of the regional agro–ecological environment. The varying vegetation cover and irrigation methods in cropland will lead to differences in mass and energy exchanges between the surface and the atmosphere, which in turn further affect the local climate and atmospheric circulation. Therefore, accurate evapotranspiration information is important for the development of irrigation systems, establishment of crop planting zones, implementation of regional water–saving agriculture practices, efficient assessment of water resources, and effective development, management, and allocation of water resources, among others.

What sets your review paper apart from previous reviews on this subject?

Given the significance of evapotranspiration, there are numerous reviews covering this subject. The varying perspectives concerning evapotranspiration have been recently reviewed, such as the role of evapotranspiration in the global, terrestrial, and local water cycles; the modeling, climatology, and climatic variability of global terrestrial evapotranspiration; best practices for measuring evapotranspiration; evapotranspiration partitioning methods; land-scale evapotranspiration from a boundary-layer meteorology perspective; spatiotemporal patterns of global evapotranspiration variations and their relations with vegetation greening. However, there is a gap in covering issues related to cropland evapotranspiration, which exhibits high variability due to its fast response to numerous factors.

There is a need to re-examine the primary factors influencing cropland evapotranspiration given the proliferation of long-term manipulation experiments, advancements in estimation models, and exponential growth in new and improved measuring methods at multiple spatial and temporal scales. In our new review, the focus is on factors encompassing key changing environments, abiotic stresses, and management practices that impact cropland evapotranspiration, along with their quantification methods.

What different methods are used for measuring evapotranspiration?

Evapotranspiration can be measured by using several methods such as plant physiology, hydrological, micro-meteorological, and remote sensing methods for different spatial and temporal scales. The leaf and plant scale transpiration can be measured by (potometer) portable photosynthesis system and sap flow method, respectively. The plot and field scale evapotranspiration can be determined by water balance, weighting lysimeter, sap flow plus micro-lysimeter, Bowen-ratio energy balance, eddy covariance, residual in the energy balance, surface renewal, and (microwave) scintillometer method. For regional scale evapotranspiration, remote sensing energy balance and remote sensing using vegetation indices are common methods.

Measurement methods for cropland evapotranspiration. Credit: Qiu et al. [2025], Figure 4

What factors do scientists consider when deciding to use one method over another?

When selecting methods to measure evapotranspiration, scientists prioritize a balance between spatial-temporal requirements, accuracy, and practicality. The choice often hinges on the scale of study: small-scale methods, such as weighting lysimeters or eddy covariance methods, provide high-resolution field-level data but lack regional coverage, whereas satellite-based remote sensing methods offer broader spatial insights at the cost of finer temporal or spatial resolution. Accuracy demands must also align with resource constraints: high-precision tools, like weight lysimeters and eddy covariance, require high financial investment, technical expertise, and maintenance, while low-cost methods, such as the water balance method, introduce large error. Environmental context further guides decisions, such as, uniform vegetation may favor Bowen-ratio energy balance and eddy covariance systems.

What are the main factors that affect cropland evapotranspiration?

Cropland evapotranspiration is affected by the meteorological conditions (e.g. radiation, air temperature, relative humidity, wind speed), changing environments (e.g. elevated carbon dioxide concentration (e[CO2]), elevated ozone concentration (e[O3]), global warming), various abiotic stresses (e.g. water, salinity, heat stresses, waterlogging), management practices (e.g. planting density, mulching, irrigation method, fertilizer application, control of diseases and pests, soil management), underlaying surface (e.g. geography, soil types), and crop–specific factors (e.g. crop type, variety, and development stages). The effect of meteorological conditions on evapotranspiration can be surrogated to a reference evapotranspiration. Therefore, in this review, the focus is on the impacts of key changing environments (e[CO2], e[O3], and global warming), abiotic stresses (water, salinity, and heat), and management practices (planting density, mulching, irrigation method, and nitrogen application) on cropland evapotranspiration.

Factors affecting cropland evapotranspiration. Credit: Qiu et al. [2025], Figure 3

What major conclusions have been drawn about these factors?

There is general agreement that e[O3], water and salinity stresses, and adopting drip irrigation all lead to lower total growing–season evapotranspiration for almost all crops. However, total growing–season evapotranspiration in response to e[CO2], warming, heat stress, planting density, and nitrogen application were inconsistent across studies.

The impacts of e[CO2] and e[O3], water and salinity stresses on total growing-season evapotranspiration are mainly through stomatal conductance, the ability of soil to conduct water to roots, development of roots and leaf area, microclimate, and possibly phenology. The effect of warming on total growing–season evapotranspiration can be largely explained by both variations in ambient growing–season mean temperature and growing duration. Total growing-season evapotranspiration in response to heat stress (or mulching and appropriate nitrogen supplement) is a compromise between reduced (or enhanced) transpiration and increased (or decreased) evaporation, along with possibly a shortened growth period. Differences in evapotranspiration under varying planting densities can be explained by the direct and indirect effects of leaf area on the constitutive terms of evapotranspiration. The variation of total growing–season evapotranspiration under drip irrigation compared to conventional irrigation was affected by smaller soil wetting area, shortened growing season, less energy partitioning to evapotranspiration, and changes in crop characteristics and microclimate.

What are some of the remaining questions where additional modeling, data, or research efforts are needed?

1. The influence of elevated ozone concentration on stomatal conductance can be represented using an adjusted version of the Jarvis function. However, there has been little effort to integrate this response into the Penman-Monteith model, which is used to estimate evapotranspiration.
2. Many controlled manipulation experiments are underreported varying types of warming on crop evapotranspiration. Water balance method, the residual in the energy balance method, sap flow plus micro–lysimeters, or even weighting lysimeters can be used to observe cropland evapotranspiration under several warming scenarios.
3. There are few studies on evapotranspiration responses to heat stress, and most are based on pot experiments in phytotrons or artificial climate chambers. Obtaining larger–scale data of evapotranspiration under heat stress is beneficial to understand heat stresses on evapotranspiration.
4. Models for describing effects of elevated CO2 and ozone concentration on evapotranspiration using a modified Priestley–Taylor and crop coefficient models are rarely reported. More efforts are needed to develop and test these two models.
5. In practice, cropland evapotranspiration is jointly affected by multiple factors. The impact of multiple factors on cropland evapotranspiration is a complex and multifaceted phenomenon that requires long–term consideration of many environmental stressors and their interactions.

—Rangjian Qiu (qiurangjian@whu.edu.cn, 0000-0003-0534-0496), Wuhan University, China

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

Citation: Qiu, R. (2025), Decoding crop evapotranspiration, Eos, 106, https://doi.org/10.1029/2025EO255015. Published on 6 May 2025. 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.

Summers are getting hotter and drier in the Eurasian landmass due to an atmospheric circulation pattern further aggravated by anthropogenic factors. The recent tandem heat-wave-drought events in the region stretching from Eastern Europe to East Asia are unprecedented, as confirmed by a new study that analyzed tree-ring data going back 300 years and climate models.

Up to 250,000 deaths from poor air quality could be prevented annually in central and western Europe by 2050 if greenhouse gas emissions are drastically reduced, say researchers.

Source: Journal of Geophysical Research: Oceans

In shallow coastal waters around the world, mud and other fine-grained sediments such as clay and silt form critical blue carbon sinks. Offshore infrastructure such as wind turbines and oil platforms, as well as fishing practices such as bottom trawling, can have major effects on the seafloor. So knowing the locations of these mud-rich sedimentary deposits is key to making coastal management decisions.

Ward et al. set out to map three mud depocenters—large offshore muddy deposits—in the coastal waters around Great Britain and Ireland. The mud-rich areas they selected were Fladen Ground, northeast of Scotland in the North Sea; the Celtic Deep, southeast of Ireland; and the Western Irish Sea Mud Belt, in the Irish Sea.

Their location at the bottom of the ocean makes these muddy deposits notoriously difficult to map. Furthermore, contemporary sedimentary deposits do not necessarily stem from modern conditions—some deposits are relicts from past ocean behavior.

To address these challenges, the authors built a paleotidal model that can re-create factors dictating the behavior and movement of ocean water, such as water depth and the speed and path of tidal currents. They reconstructed ancient seafloor topography using past sea level changes interpreted via glacial isostatic adjustment models. Using this reconstruction, they were able to simulate the tidal conditions driving the formation of the mud deposits as far back as 17,000 years ago.

The model revealed that mud settled differently across the three focal areas. In the Celtic Deep and the Western Irish Sea Mud Belt, mud appears to have accumulated over the past 10,000 years and continues to accrue today. Conversely, in Fladen Ground, the mud deposits are the result of past sea conditions and are preserved by today’s calmer tidal conditions. The results demonstrate how modeling past conditions can help map today’s carbon stores, especially in data-limited areas. The approach offers a valuable tool for managing coastal waters and preserving blue carbon, the authors say. (Journal of Geophysical Research: Oceans, https://doi.org/10.1029/2024JC022092, 2025)

—Aaron Sidder, Science Writer

Citation: Sidder, A. (2025), Mapping the ocean floor with ancient tides, Eos, 106, https://doi.org/10.1029/2025EO250172. Published on 6 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.

Author(s): G. Röpke, R. Redmer, Max Schörner, Heidi Reinholz, Uwe Kleinschmidt, and M. Bethkenhagen

Density-functional-theory-based molecular dynamics simulations (DFT-MD) are a very successful tool to calculate the electrical conductivity of materials in the region of warm and dense matter. However, it requires a correction to implement the contribution of electron-electron collisions in the low-…

[Phys. Rev. E 111, 055201] Published Tue May 06, 2025

Coastal waters around the world are increasingly losing oxygen, with dramatic consequences for both ecosystems and the people who depend on them. The Baltic Sea is a well-known example: with the consequences of spreading hypoxic or anoxic zones evident in fish kills, the decline of spawning grounds and toxic blue-green algae blooms. So why not introduce oxygen into the sea where it is most urgently needed?

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

A fascinating new paper (Corominas et al. 2025) has just been published in the journal Geoenvironmental Disasters that describes the compilation and analysis of a new dataset on fatal non-seismic rockfalls in Spain. The dataset extends back for 220 years – a remarkable feat in itself – although the detailed analysis focuses on a 150 year period between 1872 and 2021. Even better, the paper has been published open access and under a creative commons license, which means that the information can be widely circulated.

Over the period of the study, Corominas et al. (2025) identified 1,118 fatal rockfalls in Spain, causing 1,550 deaths. This is the occurrence with time:-

Temporal distribution of rockfall events and fatalities in Spain within the last 220 years. Source: Corominas et al. (2025).

The reason for starting the analysis in 1872 is clear. It is always most interesting to look at the event rate (rather than the number of deaths) – the grey line – as this is less noisy.

It is notable that the rate has fluctuated considerably with time, but that there is a distinct increase in the last 20 years.

Corominas et al. (2025) have put a great deal of effort into understanding these trends. They correctly note that a fatal rockfall is the consequence of a complex interaction of a range of factors, which can include the topography, the climate, human modification to slopes and changes to vulnerability. To illustrate this, take a look at these two graphs, from the paper:-

Temporal evolution of the number of victims caused by landslides on quarries and excavations grouped by decades. Vertical dashed blue lines represent the wettest periods identified. Source: Corominas et al. (2025). Evolution of the number of victims of road accidents caused by rockfalls. grouped by decades. Vertical dashed blue lines represent the wettest periods. Source: Corominas et al. (2025).

As before, take a look at the event rate (the grey lines). In the case of quarries and excavations, the event rate has dropped very substantially in more recent years. This is the result of changes to regulation and practice in quarries – in other words, these locations have simply become safer. The authors describe this in some detail:-

“The reason must be sought in the operational changes introduced in the quarries. One hundred years ago, quarries and slope cuts were excavated with non-technical criteria or with poor engineering design. In our opinion, the observed decrease is due to improvements in excavation procedures and the adoption of occupational safety measures. These include the Regulation of Basic Mining Safety Standards in force since 1985 and the Occupational Risk Prevention Law in force since 1996. Studies on occupational and mining safety in Spain have highlighted the role of safety standards and safety measures and risk prevention in the substantial reduction of accidents.”

On the other hand, the event rate on roads has increased dramatically, although number of actual deaths shows no clear trend. A part of this might be better reporting – perhaps rockfalls in remote mountain areas are better reported than in the past. However, Corominas et al. (2025) note the following:-

“…[T]he vast majority of events occur in mountain roads, including those of the Canary Islands and the Balearic Islands. It is therefore logical to assume that the higher incidence is due to the increase in traffic on the most dangerous mountain road sections.”

And…

“The increase in the number of victims contrasts with the investment made by the administration in mitigation measures against rockfalls and the execution of road bypasses as mentioned in the previous section. This apparent lack of effectiveness of the set of preventive actions has been observed on other mountain roads … In any case, the trend of increasing accidents highlights the difficulty of risk management on roads that cross mountain ranges following the course of the main river valleys. These are stretches affected by a diffuse hazard originated far above the road and with innumerable source areas.”

Similar increases in events and losses were also noted in mountain trails and in coastal settings, which Corominas et al. (2025) ascribe primarily to changes in human activity – i.e. more recreational activities in the mountains and on the coast. As someone once put it to me, rather starkly, there are simply more targets in these locations than used to be the case.

This summary does no more than skate over the surface of a really fabulous piece of work. There s huge insight and richness in the data, demonstrating the complexity of these events. It would be fantastic to see more studies of this type.

Reference

Corominas, J., Lantada, N., Núñez-Andrés, M.A. et al. 2025. Fatal non-seismic rockfalls in Spain. Geoenvironmental Disasters 12 [17]. https://doi.org/10.1186/s40677-025-00317-9.

Return to The Landslide Blog homepage Text © 2023. 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.

SummaryThe Lamb problem stands as a classic issue in theoretical seismology aimed at obtaining solutions for the Green's functions of point sources in elastic half-spaces. It serves as the foundation for studying vibrational signals from many sources such as walking and driving, bearing significant theoretical and practical value. While the analytical solutions exist for the Lamb problem when both excitation and reception occur on the ground, the presence of singularity makes the numerical stability of calculating the Green's functions from these analytical solutions a challenge. In this study, we propose a stable algorithm that circumvents the impact of time singularity in the analytical solutions of the Lamb problem by introducing a tiny time parameter perturbation and judiciously selecting the starting position for time discretization sampling. This means that the zero time point (i.e. the excitation time of the source pulse) and the starting time of discretization sampling may not be coincident. The advantages of this method lie in its stability, simplicity, and practical accuracy, with the calculation results aligning consistently with the theoretical geometric decay of surface waves. Additionally, analysis of field data demonstrates that our stable algorithm effectively captures the amplitude characteristics of measured footstep responses and vehicle signals. Building upon the foundation of obtaining stable discrete solutions, we further elaborate on the process of transforming the discrete sampling starting point to approach the actual zero time point infinitely, even though this tiny time parameter perturbation does not affect the simulation results.

Growing communities and extensive agriculture throughout the Western United States rely on meltwater that spills out of snow-capped mountains every spring. The models for predicting the amount of this streamflow available each year have long assumed that a small fraction of snowmelt each year enters shallow soil, with the remainder rapidly exiting in rivers and creeks.

As the new Biomass satellite settles into life in orbit following its launch on April 29, ESA has released its most extensive satellite-based maps of above-ground forest carbon to date. Spanning nearly two decades, the dataset offers the clearest global picture yet of how forest carbon stocks have changed over time.

The National Hurricane Center's forecasts in 2024 were its most accurate on record, from its one-day forecasts, as tropical cyclones neared the coast, to its forecasts five days into the future, when storms were only beginning to come together.

Communities on small islands are on the front lines of worsening flood risks—not just from severe storms but from persistent tidal flooding events. Scientists estimate that within 15 years, high-tide flood events could triple for two thirds of communities along the East and Gulf Coasts of the United States.

Have you ever thought about what would happen if all life in the ocean disappeared? A recent study explores this extreme scenario to understand how ocean biology shapes the past, present, and future climate.

Clouds form upon existing particles in the atmosphere and extreme weather events like flooding and snowstorms are related to the production of large amounts of ice in clouds.

Rare earth elements are critical to many industries—used in electric motors, medical imaging and diagnostics, oil and gas refining, and computer and phone screens. The 17 rare earth elements all have important uses and are now in the news, with China halting exports to the U.S. in retaliation for tariffs and a recently signed deal for U.S. access to these and other minerals in Ukraine.