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Source: AGU Advances

Fieldwork is a vital part of geoscience research, allowing scientists and students to directly observe, interact with, and collect data about Earth processes that cannot be replicated in the lab.

Because fieldwork involves traveling to remote locations and living in close quarters under demanding conditions, it can also lead to circumstances in which personal boundaries are crossed or safety is compromised. Shared housing, uneven power structures between students and professionals, remote locations, and long workdays can increase the likelihood of harmful field interactions.

Although the National Science Foundation, the largest agency funding field-based research, provides safety guidelines for fieldwork, many researchers in the geosciences report a range of problematic behaviors, from bullying to discrimination to sexual harassment.

Gold et al. conducted an anonymous survey of 289 AGU members to assess the frequency of harmful field interactions (excluding severe cases of violence or misconduct), which types have the most impact, and why incidents may go unreported. The researchers also asked participants what could be done to make geoscience field research safer and more inclusive.

In the survey, participants were asked whether they had experienced or witnessed harmful behaviors, including aggression and hostility, social harassment, undermining of work, inappropriate sexual behavior, assumptions and stereotyping, and violations of personal privacy.

Participants identified instances and provided additional details, such as whether they experienced or observed the harmful behavior, the relationship between perpetrator and victim, the career stage in which the event occurred, whether the field site was in a remote or accessible location, and whether the incident was reported or not.

Eighty percent of survey participants reported experiencing at least one harmful field interaction during fieldwork; the average respondent reported five harmful interactions. Though identity-based harmful behaviors, such as inappropriate sexual behaviors and assumptions or stereotyping, were commonly reported, respondents consistently identified behaviors related to professional conduct such as gatekeeping, sabotage, and devaluation of work as the most negatively impactful. Women and nonbinary researchers were disproportionately affected by devaluation of their work, bullying, unwanted sexual attention, and invasions of privacy. Career stage also affected study respondents: Early-career researchers were more likely to face incidents such as uncomfortable sleeping situations and pressure to drink alcohol. Some harmful behaviors, such as pressure to engage in unsafe activities and bullying, were more common at remote worksites.

Seventy-five percent of the most impactful instances went unreported, highlighting a need for improved safety and inclusion training, enforced codes of conduct, and independent reporting pathways to ensure that geoscience fieldwork can be safe, fair, and ethical for all participants. (AGU Advances, https://doi.org/10.1029/2026AV002402, 2026)

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

Citation: Owen, R. (2026), Four in five researchers report harmful interactions during geoscience fieldwork. A new survey suggests a path forward., Eos, 107, https://doi.org/10.1029/2026EO260286. Published on 9 September 2026. Text © 2026. 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.

Southeast Asia has spent decades trying to tackle haze from forest fires. Yet every few years, the region finds itself breathing it again. The transboundary environmental problem has become a recurrent phenomenon in the region.

Since the 1950s, the Tibetan Plateau has experienced pronounced warming and wetting. However, an overall shift toward wetter conditions does not necessarily mean that drought risk has diminished. On the contrary, against the backdrop of continued warming, compound hot-dry events—characterized by the simultaneous occurrence of high temperatures and drought—have become an increasingly important climate risk across the plateau.

SummaryHessian–vector products (HVPs) provide matrix-free access to second-order information in full-waveform inversion (FWI), enabling the use of truncated-Newton updates with improved convergence. This may result in enhanced imaging of small-scale scatterers in strongly heterogeneous, high-contrast media. In the time domain, standard adjoint-based HVP derivations are often presented either via perturbation theory or via a Lagrangian (Lagrange-multiplier) framework. Although these routes are formally equivalent, their correctness hinges on a precise treatment of transpose/adjoint placement, boundary/endpoint terms, and the discrete inner product used by the numerical solver. Revisiting these derivations, we show that a commonly used Lagrangian expression for the first HVP contribution can be incorrect when the wave equation operator L is not symmetric, and that rewriting the first term of the HVP, $\mathcal {H}_1$, using L† (or equivalently, swapping the contraction order) requires accounting for the associated boundary terms, where the L† indicates the adjoint of L. To resolve this ambiguity, we provide a complete Lagrangian formulation that explicitly incorporates initial and boundary conditions, together with a Green-identity-based treatment that distinguishes purely algebraic transpose identities from true operator adjoints obtained by integration by parts. We validate the resulting gradient and HVP expressions against reference HVPs computed by automatic differentiation (AD) using an independent JAX computational graph, which we term FDCompGraph. FDCompGraph reproduces the same discrete time stepping, source/receiver injection, and convolutional perfectly matched layer (CPML) treatment as the PDE solver, enabling apples-to-apples validation after matching wavefields under identical discretization and CPML settings. Using the first-order velocity–stress acoustic vertically transversely isotropic (VTI) system with CPML (a representative case where L is non-symmetric), we demonstrate that incorrect handling of $\mathcal {H}_1$ can yield errors up to approximately 400 per cent for HVP in ε and approximately 40 per cent for HVP in δ, whereas the HVPs in Vp and ρ are numerically unaffected. We further assess numerical errors unique to HVP evaluation, which requires perturbed wavefields and their time/space derivatives. In acoustic VTI tests using the damping sponge boundary condition, we observe HVP sensitivity losses of approximately 10 per cent amplitude compared with the results obtained using the CPML boundary condition. These errors may be difficult to diagnose because the commonly used finite-difference check, H δm ≈ g(m + δm) − g(m), is itself a linear approximation, particularly when the gradient g is computed using wavefields affected by the same imperfect boundary absorption. To make accurate HVPs practical at scale, we develop Devito–Hdm, a storage- and I/O-efficient Devito-based engine for co-simulating the required forward, adjoint, tangent, and second-adjoint system, with CPML-consistent checkpointing and partially on-the-fly correlations. As an application, we perform three-parameter VP–ε–δ acoustic VTI FWI using Newton–CG across models with increasing scatterer density and compare it against standard NLCG and L-BFGS. This application shows that incorporating HVP information overall yields a more reliable recovery of small-scale scatterer perturbations at approximately the same computational cost.

SummaryDip is often read from a regularized electrical resistivity tomography (ERT) image without a parameter-specific uncertainty. Image-resolution measures describe how an inversion blurs the resistivity field, but they do not give a noise-dependent limit for the dip of a geological interface. We derive that limit from the 2.5-D forward operator using Fisher information and a Cramér–Rao bound (CRB). The background resistivity is profiled out in log-data space. For a specified structural family, the dip standard error satisfies $\sigma _\theta \ge \sigma /\left\Vert \partial g_0/\partial \theta \right\Vert _{P_{C_0}}$. We also derive a marginal bound for unknown geometry and a first-order bias caused by structural misspecification. Tests with a 30-electrode dipole–dipole array show that the maximum-likelihood estimate attains the CRB when the fitted family is correct. At 3 % noise, the single-parameter floor is 0.14–0.50○ and the geometry-marginalised floor is 0.33–0.72○. Holding a coupled geometry parameter one cell away from its true value instead produces a 3–5○ dip bias. This is 6–25 times the formal floor. An ablation attributes most of the bias to thickness, width, or depth rather than resistivity contrast. The result is conditional on the chosen model family: the CRB measures noise-limited precision within that family, whereas the bias measures the cost of using the wrong geometry. For the cases tested here, improving an independent geometric constraint is therefore more useful than further reducing data noise.

Researchers have developed a method for extrapolating sea surface temperatures from sparse data that is significantly more accurate than other commonly used computational methods and slightly more accurate than the best-performing AI model, while taking a fraction of the time to train. The work has implications for both short-term weather forecasting and longer-term climate predictions.

Across southern Europe, increasingly extreme heat, wildfire and intense rainfall are forcing planners to consider how one event can alter the risk of the next. Portugal's exceptionally wet winter and another summer of wildfire risk are an example of this. As a professor of architecture and climate change adaptation who has been following the cyclical nature of weather extremes in the Pinhal Interior region since the deadly 2017 fires, I explain why prevention must connect forests, settlements, slopes and waterways.

Radiation from space is constantly entering Earth's atmosphere, but how much of it reaches the altitudes used by commercial aircraft depends not only on height and location, but also on the activity of the sun. A new study based on high-altitude balloon measurements over southern Israel has mapped these changes through the atmosphere and found that radiation levels at aviation altitudes rise as solar activity falls.

Researchers at The University of Manchester have developed a new physics-based artificial intelligence approach that, for the first time, enables accurate global-scale predictions of how dissolved organic carbon moves between seawater and marine sediments, a crucial but previously unquantifiable component of the planet's carbon cycle.

Geochemical studies of volcanic rocks from Baffin Island, Canada, and Iceland suggest that some of the water dating back to Earth's formation may still be preserved deep within the planet. However, it has remained unclear which minerals could store such quantities of water under the extreme conditions of Earth's interior.

How will global access to food, water and energy evolve in coming decades? A new study coauthored by MIT researchers suggests the answers could be very different depending on region, resource and income.

Drylands are defined as regions where rainfall is low relative to the atmosphere's ability to draw water from soil and plants. Expanding boundaries of these regions are frequent concerns in climate change considerations. While they can support large populations and ecosystems, dryland expansion can worsen water scarcity, land degradation and desertification.

The year is 2060. London shudders through months of Nordic winter freezes. Across northern Europe, oak and beech forests wither under severe frost and drought, while cereal yields collapse from temperatures plunging as low as 27 degrees Fahrenheit below today's averages. In U.S. coastal cities such as Miami and Charleston, South Carolina, sea levels have risen three feet (about 0.9 meters), with routine tidal flooding washing away streets. Meanwhile, in the North Atlantic, deep-sea nutrients remain trapped on the ocean floor, starving plankton blooms and triggering a cascade of die-offs from cod to migrating whales. The ocean's engine has stalled.

The mountain section whose collapse triggered fatal floods in Nepal and China on Aug. 26 had experienced unprecedented heat for the time of year, meteorological data analyzed by a researcher show.

Marine heat waves are a consequence of climate change and are increasingly altering marine and coastal regions worldwide. An international study led by the Helmholtz-Zentrum Hereon now shows that many coastal seas absorb more CO₂ from the atmosphere during these extreme events than under normal conditions. The effect is particularly pronounced in polar and subpolar shelf seas of the Northern Hemisphere, where sea ice is declining as temperatures rise.

The first national map of Ireland's exposure to climate hazards, including rising sea levels and storm surges, has identified the stretches of coastline facing the greatest pressures, providing critical new evidence to support coastal management and climate adaptation.

Single-celled algae within delicate glass-like needles, Pseudo-nitzschia diatoms may be tiny, but they can play a huge role in the ecosystems they occupy.

“Domoic acid is rough. It’s a neurotoxin. It’s nerve damage.”

When types of Pseudo-nitzschia that make domoic acid proliferate during harmful algal blooms off California’s coast, marine mammals, seabirds, and humans who eat toxin-laced fish and shellfish can become gravely ill.

“Domoic acid is rough. It’s a neurotoxin. It’s nerve damage,” said Dave Bader, chief operations and education officer at the Marine Mammal Care Center, which rescues and cares for sick and injured marine mammals in Los Angeles County. Mass strandings of domoic acid–poisoned California sea lions on the county’s beaches were once rare but have become common in recent years. The toxin spreads through the food web as animals eat the diatoms and each other, but only some animals suffer.

This California sea lion’s curved neck and nose in the air are signs of domoic acid poisoning. Credit: Marine Mammal Care Center

In Southern California, Pseudo-nitzschia diatoms are a natural part of the phytoplankton community. For millennia, phytoplankton blooms have been tied to upwelled nutrients, which surge during La Niña and decline during El Niño. But the blooms have become more frequent and more toxic. “There’s just much more domoic acid than there used to be,” said Clarissa Anderson, an oceanographer at the University of California, San Diego’s Scripps Institution of Oceanography.

Worldwide, harmful algal blooms are growing more harmful, often for both global reasons like climate change and ocean acidification and local reasons like nutrient levels in wastewater runoff.

But how big a role do local factors play? To find out, Anderson and her colleagues modeled Pseudo-nitzschia diatoms and coastal processes in Southern California to discover how much the urban area’s wastewater and runoff affect blooms and domoic acid in a study published in Harmful Algae.

Proliferating Diatoms and Toxins

Southern California’s 23 million residents create a tremendous amount of wastewater. Treatment removes pathogens, but nutrients like nitrogen persist. Of the nitrogen that flows from land to sea in this region, nearly all of it—97%—comes from wastewater, explained Marco Sandoval-Belmar, an oceanography postdoctoral researcher at the University of California, Los Angeles, and lead author of the study. Of the remaining nitrogen, 2% is from urban or agricultural runoff. Less than 1% is natural.

Pseudo-nitzschia reproduce rapidly with nitrogen as long as they have other nutrients, particularly silicon, which they need for their glassy shells. If silicon is in short supply, the diatoms can’t reproduce, but if they still have nitrogen, they keep making domoic acid. Silicon in the region, mainly found in upwelled water, has dwindled for decades, said Anderson. With less silicon rising from the deep and more nitrogen coming from land, diatoms can become domoic acid factories.

Anderson, Sandoval-Belmar, and their colleagues added a model of how Pseudo-nitzschia proliferate and produce toxin to a widely used model of coastal ocean processes and biogeochemistry. They simulated Southern California’s coastal ocean over the years 2006 to 2017, including the nutrient-filled wastewater and runoff released into the ocean over that time. To check how closely the model run mimicked real-world blooms, they compared it to data collected as part of the Southern California Coastal Ocean Observing System over the same time frame. A second model run with clean water flowing off the coast simulated what domoic acid levels would have been like without nutrients from land.

The Los Angles Hyperion Water Reclamation Plant’s treated wastewater is released into the ocean via an underwater outfall. While most wastewater at Hyperion is still conventionally treated, advanced treatment methods are now being prototyped. Credit: Doc Searls/Flickr, CC BY-SA 2.0

According to the model runs, nitrogen from land increased domoic acid levels within 15 kilometers of the shore by about 25% on average. But these modeled toxin levels were patchy; in some places domoic acid levels increased by more than 50%. “Especially super near the major [wastewater] outfalls, there is a lot more modeled production of domoic acid,” Sandoval-Belmar said.

This algal bloom, seen off the coast of Northern California in December 2025, was responsible for the deaths of at least 9 whales near Kodiak Island, Alaska. Scientists hope that research into harmful algal blooms off the coast of Southern California could help improve understanding of blooms farther north, like this one. Credit: MODIS Land Rapid Response Team, NASA GSFC

Modeling makes a strong case that “nutrients are having an impact and widening the window of opportunity for blooms in Southern California,” said Kyla Kelly, water quality program manager at the California Ocean Protection Council, which partially funded the research. Kelly hopes that similar modeling can help reveal drivers of blooms farther north as well. “A handful of research is showing there’s different drivers in the northern versus southern California Current system, which encompasses Oregon and Washington,” she said. Blooms to the north have been linked with unusually warm water, which often occurs during El Niño.

Making Harmful Algal Blooms Less Harmful

Whenever people ask Anderson what can be done to stop harmful algal blooms, she pauses.

“They’ve been around for millennia. We’re not going to just stop these blooms.”

“It’s really a hard thing to answer, because they’ve been around for millennia. We’re not going to just stop these blooms,” she said, adding that Pseudo-nitzschia diatoms can also be helpful because they are food for marine life and generate oxygen.

But the toxin the diatoms produce is more of a problem than the blooms themselves. “We can’t prevent these events, but we can lower their total impact,” Bader said. “If we remove the wastewater outfall from the equation, we don’t have a problem really anymore, or we have a problem that’s a much different scale,” he said. Smaller blooms with less domoic acid would reduce the threat to wildlife.

This image shows the forecasted probability of domoic acid off the coast of Southern California during a Pseudo-nitzschia bloom in spring 2025, according to the C-HARM (California-Harmful Algae Risk Mapping) model run by NOAA. Credit: NOAA ERDDAP

Methods exist to scrub nearly all nitrogen from wastewater, and there is an appetite to tackle land-based sources of nitrogen in California, Kelly said. “The State Water Resources Control Board is considering water quality regulations to address ocean acidification, eutrophication, and the effects of anthropogenic nutrients on ocean waters,” Kelly wrote in an email to Eos. In addition, some wastewater treatment plants have pledged to reduce nutrients on their own. But it is not a simple fix: The changes will be costly and take decades to implement.

Though Southern California’s enormous population is contributing to the nitrogen problem, it also means there is no shortage of coastal residents looking out for animals in distress. “Keeping an eye on the ocean helps,” said Sandoval-Belmar.

—Lisa S. Gardiner (@lisasgardiner.bsky.social), Science Writer

Citation: Gardiner, L. S. (2026), Wastewater can take harmful algal blooms from bad to worse, Eos, 107, https://doi.org/10.1029/2026EO260282. Published on 8 September 2026. Text © 2026. 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): T. Morita et al.

This paper presents an experimental investigation of magnetic reconnection between two laser-produced expanding plasmas, focusing on the quantitative evaluation of the reconnection rate and energy conversion under varying initial conditions. By changing the separation distance between the drive lase…

[Phys. Rev. E 114, 035206] Published Tue Sep 08, 2026

Author(s): A. A. Shelkovoy and S. A. Uryupin

Equations describing evolution of the velocity of a rarefied ion beam in a plasma with ion-acoustic turbulence are derived and solved. An ion beam with velocity u greater than the sound speed vs decelerates due to Cherenkov radiation of ion-acoustic waves. Conversely, a beam with u<vs accelerates…

[Phys. Rev. E 114, 035207] Published Tue Sep 08, 2026

Author(s): Jan Bartsch, Alfio Borzì, Paul-Antoine Hervieux, and Giovanni Manfredi

This paper proposes an optimal control strategy to cool an antiproton plasma in a time much shorter than that required by an adiabatic process. The authors examine the length and stability of the plasma, in addition to its duration. The work suggests that optimal control techniques may be useful for experiments with plasmas, in particular with antimatter plasmas, which need to be confined and cooled before significant losses and annihilation occur.

#TimelyTopic #TechnicalAdvancement #ClearMotivation

[Phys. Rev. E 114, 035208] Published Tue Sep 08, 2026