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Arctic and subarctic soils store a significant proportion of Earth’s carbon. But rising temperatures could drain these soils of nitrogen—a key nutrient. The loss could reduce plant growth, limiting the soils’ ability to store carbon and amplifying global warming, according to a new study.

High-latitude soils store vast amounts of carbon because cold temperatures slow microbial activity. Though plants produce organic matter through photosynthesis, microorganisms can’t consume it fast enough, leading to its accumulation over time. Scientists have long worried that a warmer Arctic would accelerate microbial activity, releasing stored carbon into the atmosphere as carbon dioxide (CO2). But they also hoped that warmer temperatures would stimulate plant growth, which would reabsorb some of the carbon and partially offset these emissions.

The new research shows that the latter scenario is very unlikely because warming causes soils to lose nitrogen, a loss that could inhibit plant growth.

“We didn’t expect to see nitrogen loss.”

The findings come from a decade-long experiment in a subarctic grassland near Hveragerði, Iceland. In 2008, a powerful earthquake altered geothermal water flows in the region, turning previously average patches of soil into naturally heated zones with temperature gradients ranging from 0.5°C to 40°C above previous levels. The event created a unique natural laboratory for observing how ecosystems respond to long-term warming.

Using stable nitrogen-15 isotopes to trace nutrient flows in the landscape, the researchers found that for every degree Celsius of warming, soils lost between 1.7% and 2.6% of their nitrogen. The greatest losses occurred during winter and early spring, when microbes remained active but plants were dormant. During this time, nitrogen-containing compounds such as ammonium and nitrate were released into the soil, but with plants unable to absorb them, they were lost by either leaching into groundwater or escaping into the atmosphere as nitrous oxide, a greenhouse gas nearly 300 times more potent than CO2.

The findings were published in a paper in Global Change Biology.

“We didn’t expect to see nitrogen loss,” said Sara Marañón, a soil scientist at the Centre for Ecological Research and Forestry Applications in Spain and the study’s first author. “The soil’s mechanisms to store nitrogen are breaking down.”

A Leaner, Faster Ecosystem

The researchers also found that warming weakened the very mechanisms that help soils retain nitrogen. In warmer plots, microbial biomass and the density of fine roots—both key to nitrogen storage—were much lower than in cooler plots. Though microbes were less abundant, their metabolism was faster, releasing more CO2 per unit of biomass. Meanwhile, plants struggled to adapt, lagging behind in both growth and nutrient uptake.

“Microbial communities are able to adapt and reach a new equilibrium with faster activity rates,” Marañón said. “But plants can’t keep up.”

“This is a not-so-optimistic message.”

Heightened microbial metabolism initially results in greater consumption of the nitrogen and carbon available in the soil. After 5 or 10 years, however, the system appears to reach a new equilibrium, with reduced levels of organic matter and lower fertility. That shift suggests that warming soils may transition to a permanently less fertile state, making it harder for vegetation to recover and leading to irreversible carbon loss.

Scientists have traditionally thought that as organic matter decays faster in a warmer climate, the nitrogen it contains will become more available, leading to increased productivity, said Erik Verbruggen, a soil ecologist at the University of Antwerp in Belgium who was not involved in the study. “This paper shows that actually, this is not happening.”

Instead, nitrogen is being leached out of the soil during the spring, making it unavailable for increased biomass production. “This is a not-so-optimistic message,” Verbruggen said.

An Underestimated Source of Greenhouse Gases

With Arctic regions warming faster than the global average, this disruption to the nutrient cycle could soon become more apparent. Nitrogen and carbon loss from cold-region soils may represent a significant and previously underestimated source of greenhouse gas emissions—one that current climate models have yet to fully incorporate.

The researchers periodically returned to the warm grassland near Hveragerði, Iceland, to measure nitrogen. Credit: Sara Marañón

The researchers plan to explore the early phases of soil warming by transplanting bits of normal soils into heated areas and also to investigate how different soil types respond to heat. Marañón noted that the Icelandic soils in the study are volcanic in origin and very rich in minerals, unlike organic peat soils common in other Artic regions.

“Arctic soils also include permafrost in places like northern Russia and parts of Scandinavia, and they are the largest carbon reservoirs in the world’s soil,” Verbruggen said. The soils analyzed in this research, on the other hand, were shallow grassland soils. “They are not necessarily representative of all Arctic soils.”

Still, Verbruggen added, the study’s findings highlight the delicate balance between productivity and nutrient loss in these systems.

Soil’s abundant carbon reserves make it a major risk if mismanaged, Marañón said. “But it can also become a potential ally and compensate for CO2 emissions.”

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

Citation: Barbuzano, J. (2025), As the Arctic warms, soils lose key nutrients, Eos, 106, https://doi.org/10.1029/2025EO250282. Published on 1 August 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.

Author(s): L. Ansia, P. Velarde, M. Fajardo, and G. O. Williams

Nonthermal photoionized plasmas are now established in the laboratory and require models that treat the atomic processes and electron distribution self-consistently. We investigate the effects of inelastic thermalization in iron under intense x-ray irradiation using the atomic model BigBarT, suited …

[Phys. Rev. E 112, 025201] Published Fri Aug 01, 2025

Author(s): H. P. Le, E. V. Marley, and H. A. Scott

Electron distributions in laser-produced plasmas will be driven toward a super-Gaussian distribution due to inverse bremsstrahlung absorption [Langdon, Phys. Rev. Lett. 44, 575 (1980)]. Both theoretical and experimental evidence suggest that fundamental plasma properties are altered by the super-Gau…

[Phys. Rev. E 112, 025202] Published Fri Aug 01, 2025

Terrestrial plants drove an increase in global photosynthesis between 2003 and 2021, a trend partially offset by a weak decline in photosynthesis—the process of using sunlight to make food—among marine algae, according to a study published in Nature Climate Change.

SummaryIn this study, we compare the usability of a simplified microtremor-based empirical method and a conventional microtremor method based on an inversion analysis of a subsurface velocity structure model for constructing a map of average S-wave velocity (AVS) values. In the simplified (empirical) method, the phase velocities of Rayleigh waves, which can be obtained by processing a microtremor array, at wavelengths of 13, 25, and 40 m are regarded as AVS values from the ground surface to depths of 10, 20, and 30 m (${\overline {Vs} }_{10},{\overline {Vs} }_{20},\ {\rm{and}}\ {\overline {Vs} }_{30}$), respectively. Microtremor array surveys were conducted at 173 observation points within a 15 km × 17 km area east of Aso caldera, Kyushu, Japan (target area). AVS values are obtained by applying the empirical method to the phase velocities obtained at each observation point. The AVS values at an observation point (located near the centre of the target area) with velocity logging data are verified by a comparison with those based on the velocity logging data (i.e. overestimations by 6 per cent at maximum). It is found that for the entire target area, the spatial distribution of the obtained AVS values is consistent with the geological distribution. The AVS values within areas of the Aso-3 ignimbrite are 30–40 per cent larger than those within areas of thick soil and tephra on the strongly consolidated Aso-4 ignimbrite. In addition, the AVS values of the Aso-3 deposits are more than 10 per cent larger than those of the Aso-4 deposits and about 10 per cent smaller than those of geological units older than the Aso-3 deposits. We also apply a conventional (i.e. inversion) method to the phase velocity data at each observation point to obtain a one-dimensional S-wave velocity (Vs) structure model from which we deduce AVS values. The deduced AVS values at the velocity logging point are underestimated by -8 per cent, with differences from the AVS values obtained using the empirical method reaching 13 per cent. The average systematic difference between the two methods is 15 per cent, as determined from a statistical analysis. None the less, a strong correlation is found between the methods, with an average correlation coefficient of 0.94, with no evidence showing that either method is more accurate. The empirical method can be used to construct an AVS map if overestimation is carefully considered. This analysis also reveals that the average maximum survey depths of the one-dimensional Vs structures based on the inversion method are only 23±10 m, making them often insufficient to map ${\overline {Vs} }_{20}$ and ${\overline {Vs} }_{30}$ (the ratios of the available to total numbers of data points are only 60 and 21 per cent, respectively). In contrast, the empirical method can determine ${\overline {Vs} }_{10},{\overline {Vs} }_{20},\ \ {\rm{and}}\ {\overline {Vs} }_{30}$ at more than 80 per cent of all sites. The construction of AVS maps using the empirical method is effective in terms of the simplicity and reliability of planning, observational efficiency, and simplicity of data processing, which support a practical and objective approach to seismic assessments.

SummaryIn this study we obtain 35 903 high-quality P-wave receiver functions from 1737 teleseismic events recorded at 120 dense broadband TanluArray temporary stations deployed in and around the Tanlu fault zone (TLFZ). After station azimuth and sediment correction are made, a detailed Moho depth distribution is obtained by CCP stacking. Our results show a sharp change in the Moho depth across the TLFZ from the west to east, which well corresponds to the surface geological structure. The deepest Moho (38.0 ∼ 40.0 km) occurs beneath the Dabie orogenic belt and the Sulu orogenic belt. The Moho beneath the Luxi uplift, Jiangnan orogenic belt and Jiaodong uplift is deeper (36.0 ∼ 37.0 km), whereas the Subei basin and the southern basin of the South Yellow Sea have a shallow Moho (28.0 ∼ 30.0 km). There is an obvious Moho uplift near Weifang, which corresponds to the Changle ancient volcano on the surface and may be a channel for upwelling of hot mantle material. The Moho is unclear under the fault zone near Tancheng, which is speculated to be a channel for upwelling of hot mantle material. It may be related to upwelling of hot and wet flows in the big mantle wedge above the subducted Pacific slab that is stagnant in the mantle transition zone beneath East Asia, which is a possible cause of the 1668 M8.5 Tancheng earthquake.

A new study shows that natural dust particles swirling in from faraway deserts can trigger freezing of clouds in Earth's Northern Hemisphere. This subtle mechanism influences how much sunlight clouds reflect and how they produce rain and snow—with major implications for climate projections.

Around 800 million years ago, during the Tonian period, the Yangtze Block in South China experienced significant tectonic activity, in which the ancient supercontinent Rodinia broke off from the area that is now South China. This created the Yangtze Block plate, which then collided with the China Ocean Plate, causing an area of subduction—where the oceanic plate slides under the lighter continental plate. This process is known to result in the creation of a string of volcanoes on the surface.

Algal growth is accelerating in lakes across Canada, including those far from human development, and a new study shows that climate change is the primary driver.

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

Lakes that form on top of glaciers on Earth (called supraglacial lakes) have been observed to drain downwards when a fracture forms.  The fracture may further propagate through a process called hydrofracturing, where additional pressure is caused by the weight of the overlying water. 

Europa is a moon of Jupiter with a subsurface ocean under an outer icy lithosphere that is likely tens of kilometers thick. Taking this glacial lake analogy to Europa, Law [2025] investigates whether this process was likely to play a role in perched water bodies in Europa’s icy shell. The perched water bodies, those formed inside of the ice shell, could be created through either convective upwellings in Europa’s icy shell or through an impact to the surface. 

Illustration of scenarios discussed for perched water bodies and how they may evolve over time. Upper row: possible evolution of a perched water body that formed through convection or other in-shell processes. The collapse of the shell above the water may enable downward hydrofacturing by weakening the shell above. Lower panel: possible evolution of a perched water body that formed as a result of an impact, as an alternative way to weaken the upper shell. Credit: Law [2025], Figure 1

The author concludes that downward hydrofracture and drainage of liquid water from perched water bodies on Europa are possible if the overlying ice lithosphere is thin or mechanically weak. Such a condition might occur if there is a perched water body below a broken-up region of crust (called chaos regions on Europa) or shortly after an impact crater forms. 

If hydrofracturing is possible, this may provide a means to transport melt from near the surface of Europa to deeper parts of the icy crust, or potentially all the way to the subsurface ocean.  The movement of melt and other elements or minerals carried with it may affect the habitability of Europa by bringing nutrients and chemical disequilibria to the subsurface ocean.

Citation: Law, R. (2025). Rapid hydrofracture of icy moon shells: Insights from glaciology. Journal of Geophysical Research: Planets, 130, e2024JE008403. https://doi.org/10.1029/2024JE008403

—Kelsi Singer, Associate Editor, JGR: Planets

Text © 2025. The authors. CC BY-NC-ND 3.0
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body {background-color: #D2D1D5;} Research & Developments is a blog for brief updates that provide context for the flurry of news that impacts science and scientists today.

515 miles—roughly the distance from Washington, D.C. to Detroit, one-third the length of the Colorado River, and now, the longest lightning bolt ever recorded.

That’s right: A new analysis of satellite data has revealed that a 22 October 2017 storm over the U.S. Midwest created a lightning bolt that reached 829 kilometers (515 miles), from eastern Texas to nearly Kansas City. The record-setting bolt lasted about 7 seconds. 

The record was certified by the World Meteorological Organization (WMO), the weather agency of the United Nations, and entered into their World Weather and Climate Extremes Archive.

Researchers discovered the lightning bolt while analyzing lightning detection data from NOAA’s GOES-16 satellite. They published their findings in the Bulletin of the American Meteorological Society today. 

Imagery from the GOES-16 satellite shows the record-breaking lightning bolt. Red circles mark positively charged subsidiary branches of lightning, and blue circles mark negatively charged subsidiary branches. Credit: World Meteorological Organization, American Meteorological Society, Peterson et al. 2025, https://doi.org/10.1175/BAMS-D-25-0037.1

The 515-mile-long bolt is considered a megaflash, which refers to lightning that reaches at least 100 kilometers (62 miles). Megaflashes extend through the clouds, initiating hundreds of cloud-to-ground bolts along the way. The flash from the 2017 storm created more than 116 cloud-to-ground offshoots seen in the above map as blue and red dots.

 
Related

•  Read the report in the Bulletin of the American Meteorological Society
•  WMO Certifies Megaflash Lightning Record in U.S.A.
•  Longest Lightning “Mega-Flash” Sets a Shocking New Record
 

Less than 1% of storms create megaflash lightning; most flashes reach less than 16 kilometers (10 miles). 

Still, most people don’t realize how far from a storm lightning can strike. “The storm that produces a lightning strike doesn’t have to be over top of you,” Randy Cerveny, a geographer at Arizona State University and coauthor of the new report, said in a press release. 

Historically, scientists have detected lightning using ground-based networks that estimate location and speed based on the time it takes radio signals emitted by lightning to reach antennas. Satellite-based lightning detectors are a relatively recent addition to atmospheric scientists’ toolkit, and allow researchers to detect lightning continuously on continent-scale distances.

The previous record certified by the WMO was a flash over the southern United States and the Gulf of Mexico measured by satellite sensors to be 768 kilometers (477 miles) long. 

“It is likely that even greater extremes still exist, and that we will be able to observe them as additional high-quality lightning measurements accumulate over time,” Cerveny said.

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

These updates are made possible through information from the scientific community. Do you have a story idea about science or scientists? We’re listening! Send us a tip at eos@agu.org. Text © 2025. AGU. CC BY-NC-ND 3.0
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Every day, as the sun sets, billions of small animals make their way from the depths of the ocean to the surface to feed. As the next day begins, these zooplankton swim back down. It's the largest synchronous migration on the planet, responsible for carrying vast amounts of carbon from the ocean surface to the deep.

Since 2013, a small plot of forest in northern New Hampshire has been heated with buried cables, an experiment meant to simulate the effects of climate change on soil temperatures. Now, after a decade of artificial warming, scientists are getting a glimpse into how temperate forests may change in the future.

Previous studies of temperate forests indicated that climate change might accelerate tree growth during spring and summer growing seasons, increasing the volume of carbon that the world’s trees store and making them a critical player in fighting climate change. But a warmer world will also have warmer winters and less snow, which damage those same trees.

A new study, published in Proceedings of the National Academy of Sciences of the United States of America, indicates that changing winters could damage trees enough to offset the growth benefits of warmer temperatures. Climate models don’t take this offset into account and may be overestimating the ability of forests in the northeastern United States to fight climate change.

“Winter climate change in systems that are adapted to snow and its insulation is going to cause a reduced ability to sequester carbon,” said Pamela Templer, a forest ecologist at Boston University and a coauthor of the new study. 

Hot and Cold

To test how changing snow behavior in a warming temperate forest might affect carbon sequestration, the research team measured biomass changes in red maple trees in three types of plots: one plot treated with warming cables during the growing season, one treated with both warming and recurring freeze-thaw cycles in the winter, and reference plots with no treatments.

Each time it snowed from 2013 to 2022, researchers shoveled the insulating snow off the second plot, exposing soil to the freezing air for 72 hours. Then, they thawed the soil for 72 hours with warming cables. 

Researchers measured changes in biomass, a proxy for carbon storage, with metal bands that record the diameter of trunks.

The freezing and thawing cycles simulated in the study will likely become more common with climate change, said Kyle Arndt, a climate scientist at the Woodwell Climate Research Center who was not involved in the new study. “In these kinds of northern forests, this is expected to happen more often.”

“What’s striking here is that when you add the effect of winter climate change, the difference [between warmed and unwarmed plots] disappears.”

Those cycles of freezing and thawing damage tree roots, limiting their ability to take up nutrients, including nitrogen, meaning the trees can’t grow as much as they would following a more stable winter.

The plot of trees that was warmed in the growing season sequestered 63% more carbon than the reference plots. But the plot with both warmer growing seasons and additional freeze-thaw cycles sequestered just 31% more. Analysis of the growth data showed that the difference between this plot and the reference plot (with no warming or freeze-thaw cycles) was not statistically significant.

“What’s striking here,” Templer said, “is that when you add the effect of winter climate change, the difference [between warmed and unwarmed plots] disappears.”

The results align with a previous study from the same research group showing a 40% reduction in aboveground tree growth for sugar maple trees when insulating snow was removed.

Arndt said the results made sense and that the particularly long dataset added credence to the findings. 

The results may also have implications for nutrient cycling on the ecosystem scale, said Carol Adair, a forest ecologist at the University of Vermont who was not involved in the new study. When roots are damaged by freeze-thaw cycles, all the nitrogen they can’t absorb is left in the soil and flushed into watersheds during the spring melt. 

“We see a lot of nutrient loss happening [in the winter],” Adair said. Nutrients lost to surface waters could spur harmful algal blooms and even create a feedback loop that further decreases forest growth. Climate change–driven rain, rain-on-snow, and snowmelt events during warmer winters exacerbate the issue.

Forests’ Role in Carbon Storage

The results suggest that current models of the climate system may be overestimating how much carbon mid- to high-latitude forests will be able to sequester over the next couple of centuries, according to the authors.

“Without including these freeze-thaw cycles, they’re going to be overestimating [carbon storage] over time.”

The researchers searched existing model projections and could not find any that included the complex freeze-thaw dynamics identified in the plots, said Emerson Conrad-Rooney, a doctoral student and ecologist at Boston University and lead author of the new study. “How winter climate change can impact forest processes is not typically incorporated.”

“The models are really only including some of these net positive impacts” of climate change on northern forest biomass, Arndt said. “Without including these freeze-thaw cycles, they’re going to be overestimating [carbon storage] over time.”

“If we want to understand how future forests are going to sequester carbon, we need to know mechanistically how they’re going to behave [under a changing climate],” Templer said.

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

Citation: van Deelen, G. (2025), Warming winters sabotage trees’ carbon uptake, Eos, 106, https://doi.org/10.1029/2025EO250278. Published on [DAY MONTH] 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.

It was a single lightning flash that streaked across the Great Plains for 515 miles, from eastern Texas nearly all the way to Kansas City, setting a new world record.

A new study using data collected by NASA's Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite established a novel method to determine how productive plants are worldwide. The findings were published in IEEE Geoscience and Remote Sensing Letters.

SummaryThe Limpopo transform margin offshore southern Mozambique results from the separation of Gondwana along the East Africa continental margin. Over the last three decades, more than thirty different reconstruction models have been proposed, sometimes contradicting each other. Here, we present results from the travel-time tomography of wide-angle seismic data acquired during the second China-Mozambique Joint Cruise, allowing the interpretation of the crustal structure and magmatism in the Limpopo Corridor and the Mozambique Basin. Using these results, we determine the extent of the Continent Ocean Transition and the location of the Continent Ocean Boundary on the southern Mozambique margin. The seismic profile is 442-km long, extending from the eastern part of the North Natal Valley in the west and crossing the Limpopo Corridor and the Mozambique Basin to the east. Based on the tomographic velocity model, we delineated three distinct domains from west to east along the profile: (1) a western transitional domain with anomalous or mixed crust, bounded by the Mozambique Fracture Zone to the east, where the crust gradually thins eastward from ∼14 km at distance 45 km to ∼10.8 km at distance 140 km; (2) a domain of thickened oceanic crust resulting from enhanced magmatism, where the crust thins eastward, from ∼10.8 km to ∼8.5 km over ∼100 km distance; and (3) an eastern domain of normal oceanic crust, where the average crustal thickness is ∼8 km. We suggest that (1) the western transitional domain roughly corresponds to the Limpopo Corridor and is of continental crustal origin but was affected and modified by strike-slip motion and magmatic activity, resulting in anomalous or mixed crust. The eastern Continent Ocean Boundary of the Limpopo Margin is close to the Mozambique Fracture Zone; (2) The thickened oceanic domain thins eastward, and the crustal velocity and thickness change dramatically compared to the oceanic domain. This domain seems to have strongly interacted and contaminated by the Limpopo Corridor during the opening of Mozambique Basin and seafloor spreading; (3) The eastern oceanic domain shows a relatively uniform oceanic crust of ∼8 km and high velocity up to 7.4 km/s in the lower crust, suggestive of a hotter mantle that produces more MgO-rich melts probably due to the influence of a thermal mantle anomaly.

SummaryThe downward continuation of gravity field can provide valuable information for 3-D gravity-field modeling, shallow-layer geological interpretation, source depth estimation, and so on. However, downward continuation is ill-posed, and traditional approaches often suffer from computational instability, poor noise resistance, and limited continuation depth, making it a longstanding challenge in gravity data processing. We present a new approach for fast, stable and large-depth downward continuation of gravity anomalies by using frequency-domain 3-D imaging. First, we utilize the frequency-domain 3-D imaging approach to invert the gravity anomalies at the original observational plane to quickly obtain the equivalent density model in the subsurface. Then, we apply the optimized strategy of frequency-domain 3-D forward calculation on the equivalent density model to rapidly obtain high-precision gravity anomalies at the downward-continuation plane. The synthetic data tests prove the effectiveness of our approach, and demonstrate that our approach enables fast, stable, robust noise resistance and large-depth downward continuation of large-scale gravity anomalies data, and has superior performance compared to the traditional regularized filtering approach and spatial-domain equivalent-source approach. The real data test of the free-air gravity anomalies data in the central South China Sea also verifies the fast, stable and reliable downward continuations of large depths by our approach. The 3-D gravity-field model built by our approach will provide significant support for the tectonic studies and resource exploration in this area.

SummaryModelling and inversion of controlled-source electromagnetic data requires elaborate numerical tools. The major challenge is the high computational cost of computing solutions to numerous forward problems (for the forward responses as well as the sensitivity matrix). Forward modelling is accomplished using either a direct or an iterative solver. Current modelling suites predominantly employ direct solution methods in the forward operator since multiple solutions are easily accessible using inexpensive and quick forward-backward substitution after an initial resource-demanding matrix factorisation step. Iterative techniques, on the other hand, require little resources for single forward solutions, and are yet very time consuming if solutions for many right-hand sides are to be computed. Evaluations of different solution techniques for modelling and inverse problems are only sparsely investigated. In light of this, we integrated an iterative solver as alternative in the forward and and inversion operators of the open-source software custEM and pyGIMLi. In particular, we implemented a two-level iterative scheme where the outer solver employs a generalised conjugate residual algorithm preconditioned with a highly efficient block-based preconditioner for square blocks. The inner-level solver is either of the same type as the outer solver, but preconditioned with the auxiliary-space Maxwell preconditioner, or may alternatively be a direct solver. In this paper, we evaluate the described iterative forward operator for forward modelling tasks for the Marlim R3D model for a single as well as numerous right-hand side vectors and compare the performance to the direct solver MUMPS. We further investigate the solver’s applicability on small and medium-sized computing platforms. We then examine the iterative solver for inversions of synthetic land-based and semi-airborne data in terms of computational requirements. Our results demonstrate that forward modelling tasks are best performed using an iterative approach for single source problems. Moreover, simulations of large and complex problems are accessible on even on small computing platforms such as laptops in very reasonable time. For inversions, the iterative forward operator, in particular the mixed iterative-direct-based one, performs equally well in terms of time as the direct one while reducing the memory demands for the computations of the forward responses and the data sensitivities.

The Gulf of Maine—home to commercial fisheries for oysters, clams and mussels—has unexpectedly avoided an increase in seawater acidity, helping to preserve the health of its fisheries.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Geochemistry, Geophysics, Geosystems

More than a century ago, Alfred Wegener proposed that the Atlantic Ocean formed after North America drifted away from Africa and Eurasia. Much later, the theory of plate tectonics explained this movement as resulting from the formation of new oceanic crust in the space between the continents. But how did the the initial rift between the landmasses form, and how did it transition into a mid-ocean spreading ridge? Answers to these questions have remained elusive, partly because the time history of the rifting process has been difficult to decipher.

Foster-Baril et al. [2025] shed new light on the “rift to drift” transition by dating igneous rocks across a broad swath of the North American margin. They find that continental breakup and the subsequent transition to seafloor spreading was accomplished by three major pulses of magmatism. The first pulse was the largest, and involved extensive melting of mantle from below as the rift opened across a wide area. The second and third pulses, which were smaller, helped to localize the extensional deformation into a confined region. This localization facilitated the transition to symmetric seafloor spreading.

This sequence suggests that continental breakup happens across a much broader area, and over a longer time period, than was previously thought. It is still unclear if other continental breakup events also featured a series of magmatic pulses, or if the North American margin was unique in this way. Can this sequence also help us to understand “failed rifts” that never transition into seafloor spreading events? More studies that examine magmatism across broad regions of a rifting zone can help to answer such questions.

Citation: Foster-Baril, Z. S., Hinshaw, E. R., Stockli, D. F., Bailey, C. M., & Setera, J. (2025). Duration and geochemical evolution of Triassic and Jurassic magmatism along the Eastern North American Margin. Geochemistry, Geophysics, Geosystems, 26, e2024GC011900.  https://doi.org/10.1029/2024GC011900

—Clinton P. Conrad, Associate Editor, G-Cubed

Text © 2025. The authors. CC BY-NC-ND 3.0
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