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Predictive Mapping of Soil Texture Using vis–NIR Spectroscopy and Machine Learning in Semi-Arid Eastern Mediterranean

Publication date: Available online 17 April 2026

Source: Advances in Space Research

Author(s): Yavuz S. Turgut, Y.Kenan Koca

Design and Analysis of Controllable Domain for Point Return Orbits Using Velocity Surfaces

Publication date: Available online 17 April 2026

Source: Advances in Space Research

Author(s): Zhenjiang Du, Heng Jing, Haiyang Li, Hua Wang

Why delaying climate action now means higher seas by 2100

Phys.org: Earth science - Fri, 04/24/2026 - 17:00
Imagine your favorite sunny beach. Anywhere will do. You look out and see the ocean stretching to the horizon. To a glaciologist, that view is not just water; it's melted ice. Our new study shows that the best case sea-level rise scenarios may now be out of reach. The work is published in the journal Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

Widening Channels and Westerly Winds Together Formed Earth’s Strongest Current

EOS - Fri, 04/24/2026 - 12:39

A critical ocean current that regulates Antarctica’s climate may have formed only once continents separated and winds aligned with new ocean passageways, according to a new study published in the Proceedings of the National Academy of Sciences of the United States of America.

Today, the Antarctic Circumpolar Current transports more than 100 times as much water as all of Earth’s rivers combined and, critically, insulates the Antarctic Ice Sheet from heat at lower latitudes. A clear picture of the origins of this current can help scientists further understand the relationships between contemporary ocean dynamics, the global climate, and ice formation in Antarctica.

“It’s very interesting to learn more about this current, how it developed, and what role it played in the climate change that was happening at that time,” said Hanna Knahl, a paleoclimatologist and doctoral student at the Alfred-Wegener-Institut in Germany and lead author of the new study.

The Birth of a Current

About 34 million years ago, Earth was undergoing a climatic shift, now known as the Eocene-Oligocene transition, during which atmospheric carbon dioxide decreased and the planet cooled.

Earth’s tectonic plates in the Southern Ocean moved away from each other, opening and deepening bodies of water such as the Tasmanian Gateway and the Drake Passage, which separate Antarctica, Australia, and South America.

For years, scientists hypothesized that the alignment of these newly formed waterways, along with westerly winds, could have channeled ocean water and spurred the formation of the Antarctic Circumpolar Current.

“The exact position of the westerly winds and their relative position to the [ocean] gateways have to click together.”

To test that hypothesis, Knahl and her colleagues simulated conditions of the early Oligocene Southern Ocean with a coupled model that included ocean dynamics, atmosphere and wind patterns, temperatures, ice sheet growth, and precipitation. The research team compared these simulations to data from actual Antarctic sediment cores and scans of the ocean floor.

Results confirmed that westerly winds were necessary for the Antarctic Circumpolar Current to form.

“The exact position of the westerly winds and their relative position to the [ocean] gateways have to click together,” Knahl said.

Joanne Whittaker, a marine geophysicist at the University of Tasmania who was not involved in the new study, was a coauthor of a 2015 study that proposed westerly wind alignment played a role in the formation of the current. Knahl’s study presents a more sophisticated model of the early Oligocene Southern Ocean and is a great next step in the investigation of the current’s origins, Whittaker said.

“They did a really nice job of taking a range of different people’s work and linking it all together,” she said.

Oligocene Understandings

“If you can have a model that works in the past, it’s going to give you confidence that it’s going to work for the future, as well.”

Scientists often use Earth’s past behavior to better understand how Earth systems may behave in the present or future. “If you can have a model that works in the past,” Whittaker explained, “it’s going to give you confidence that it’s going to work for the future, as well.”

The Eocene-Oligocene transition is a key to understanding the relationship between atmospheric carbon, ocean dynamics, and the glaciation of Antarctica, Whittaker said. Knowing how the current’s behavior affected carbon uptake millions of years ago helps scientists model how the present current’s behavior might also affect atmospheric carbon.

In addition to carbon uptake, the new research hints at how changes in westerly winds may influence the advance and retreat of the Antarctic Ice Sheet. Some modeling and proxy data indicate the westerly winds that spurred the Antarctic Circumpolar Current’s formation 34 million years ago have shifted in the past century and may continue to shift in the future. Understanding the role these winds initially played in the current’s development may shed light on the current’s present ability to guard the Antarctic Ice Sheet from warmer air masses.

There are still Oligocene patterns that require more research to sort out, though. For example, modeling in the new study showed interesting asymmetries in the timing of the development of different parts of the Antarctic Circumpolar Current, Knahl said. Scientists know from proxy data and modeling that similar asymmetry exists in the history of the Antarctic Ice Sheet; the ice sheet in East Antarctica began to form about 7 million years before the ice sheet began to form in West Antarctica.

“It could be interesting to see if there’s a connection between the asymmetries that we see here,” Knahl said. “Are they linked, or were they more or less independent?”

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

Citation: van Deelen, G. (2026), Widening channels and westerly winds together formed Earth’s strongest current, Eos, 107, https://doi.org/10.1029/2026EO260126. Published on 24 April 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.

How Space Plasma Can Bend the Laser of Gravitational Wave Detectors

EOS - Fri, 04/24/2026 - 12:00
Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Space Weather

TianQin is a geocentric space-borne gravitational wave detector, which is proposed to detect the gravitational wave by measuring tiny displacements using inter-satellite laser interferometry. However, the space surrounding the orbit and laser links of TianQin is not a vacuum—but filled with plasma, which can bend the laser links and induce pointing accuracy noise in the gravitational wave detection.

Based on a global magnetohydrodynamic model, Zhou et al. [2026] use a ray-tracing method to obtain the laser deflection caused by laser propagation through plasma, and to evaluate the pointing accuracy noise.  The result shows that the laser deflection effect caused by large-scale space plasma distribution under quiet to moderate space weather conditions does not represent a fundamental risk to the TianQin mission. However, during severe space weather events, the laser propagation effect could become a considerable noise in the gravitational wave detection.

This work establishes a connection between space weather and gravitational wave detection. Furthermore, this work raises awareness of the impact of space weather on other high-precision electromagnetic wave measurements in space.

Citation: Zhou, S. W, Su, W., Zhou, S. Y., Li, C. F., & Zhang, J. X. (2026). The pointing error due to laser propagation in space plasma for TianQin gravitational wave detection. Space Weather, 24, e2025SW004784. https://doi.org/10.1029/2025SW004784

—Jiuhou Lei, Editor, Space Weather

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.

Climate change means more landslides in NZ—but new tech can help reduce the risk

Phys.org: Earth science - Fri, 04/24/2026 - 00:00
Thousands of slips in Tairāwhiti in January. The loss of eight lives in the Bay of Plenty later that month. And, days ago, landslides that damaged homes, forced evacuations and blocked roads across the North Island.

Seismic travel-time tomography under the peak ring of the Chicxulub impact crater

Geophysical Journal International - Fri, 04/24/2026 - 00:00
SummaryWe present the results of a three-dimensional seismic tomography study of the upper crust beneath a quadrant of the peak ring structure of the Chicxulub meteorite impact crater, Mexico. Reflection and refraction travel-times from a grid of seismic profiles recorded by a 6 km streamer and 48 ocean bottom seismometer stations were inverted to give a well-resolved three-dimensional velocity model to a maximum depth of 6-8 km. The model comprised the thin water layer, a layer of low seismic velocity post-impact sedimentary infill, and the crater basement, which was separated from the fill by the interface representing the top of the crater, defined by normal incidence reflection picks. The crater basement shows a cylinder-shaped feature extending vertically downwards beneath the topographic peak ring to at least 8 km, the depth of resolution of this survey, characterised by slower seismic velocities than in the surrounding rocks at the same depth. This result supports and extends the observations of previous seismic refraction work in the peak ring, and also of scientific drilling, that the material in the peak ring has significantly reduced seismic velocity compared to typical granitic basement lithologies. We used the velocity model to perform a pre-stack depth migration of a key seismic reflection profile. In the best-fitting model presented here the prominent dipping reflector previously identified on seismic reflection profiles, which projects to the outer edge of the peak ring, dips inwards and crosses the low velocity cylinder without an apparent first order contrast in impedance. This result implies that the reflectivity of this dipping reflector is due to a thin, high-contrast layer such as entrapped impact melt or hydrothermal alteration within the overturned structures. We also identify well-imaged slump blocks from the crater rim/inner ring inwards, variations in the height and width of the peak ring, and associated variations in the velocity contrast that characterises the anomaly beneath the peak ring.

Ancient African topography remotely modulated the South Asian summer monsoon millions of years ago, study finds

Phys.org: Earth science - Thu, 04/23/2026 - 22:40
The South Asian summer monsoon sustains billions of people today. For a long time, the prevailing scientific view has held that the formation and intensification of the South Asian summer monsoon were primarily controlled by the rapid uplift of the Tibetan Plateau. However, geological records present a long-standing puzzle from the Early to Middle Miocene (25 to 15 million years ago): the South Asian monsoon rainfall was remarkably strong, even though the Somali Jet—the primary wind system transporting moisture—was relatively weak.

How a sinking lithospheric root raised Mongolia's Hangay Mountains

Phys.org: Earth science - Thu, 04/23/2026 - 21:50
Central Mongolia's Hangay Mountains rise more than four kilometers above sea level, forming a dramatic dome that shapes the region's climate. But for decades, geologists have been puzzled: What caused this massive mountain range to form so far from any active plate boundary? Unlike the linear Himalayas, which are still rising from the collision of India and Asia, the dome-shaped Hangay Mountains show little internal deformation, suggesting a different and previously unknown mechanism.

A huge tectonic boundary shook the ground where dinosaurs once stood

Phys.org: Earth science - Thu, 04/23/2026 - 21:10
Scientists have discovered a Jurassic tectonic plate boundary that could help to predict what the planet might look like millions of years into the future. Dr. Jordan Phethean, Senior Lecturer in Earth Sciences at the University of Derby, is part of a team of researchers that has unveiled a previously unrecognized, major tectonic feature of Earth, in East Africa. The new structure, which has been likened to an ancient version of the San Andreas fault in California, was partially responsible for the breakup of the supercontinent Gondwana 180 million years ago in the Jurassic period.

How earthquakes stop: Near-fault records uncover overlooked phase

Phys.org: Earth science - Thu, 04/23/2026 - 18:00
While analyzing strong-motion data close to fault lines, a group of researchers at Kyoto University noticed something unexpected: a negative phase in the waveforms, a pattern that did not conform to the existing interpretations of rupture dynamics. Its regular appearance in the records near rupture end points suggested that the team might be seeing something new. The study has been published in Science.

Nuclear war at Ukraine-Russia border could trigger years of global climate disruption and radioactive fallout

Phys.org: Earth science - Thu, 04/23/2026 - 15:40
Geopolitical tensions in Eastern Europe underscore the urgency of addressing the climate and radiological consequences of a regional nuclear conflict. Even a small-scale nuclear conflict at the Ukraine–Russia border could cause years of severe global climate disruption and radioactive fallout across much of the world, new research suggests.

These eight coastal cities sit on America's flood front line, and AI shows why

Phys.org: Earth science - Thu, 04/23/2026 - 15:26
New York, New Orleans and Miami are among the eight cities along the US Gulf and Atlantic coasts facing the highest flood risk, according to a new study published in Science Advances. Scientists developed a new AI-driven framework and combined it with historical flood-damage data to not only identify high-risk coastal areas but also pinpoint the underlying factors driving that risk.

How an Atlantic island narrowly escaped 'stealthy' eruption

Phys.org: Earth science - Thu, 04/23/2026 - 14:20
Thousands of earthquakes affecting Portugal's São Jorge Island in the Azores in March 2022 were triggered by a vast sheet of magma (molten rock) rising from more than 20km below Earth's surface and stalling just 1.6km beneath the island, according to a new study led by UCL (University College London) researchers.

Scientists discover how the Twelve Apostles were formed—and their real age

Phys.org: Earth science - Thu, 04/23/2026 - 14:00
Scientists at the University of Melbourne have uncovered for the first time how Australia's iconic Twelve Apostles were formed, finding tectonic plate movements over millions of years lifted and tilted the giant structures out of the sea.

Hurricane Helene Ravaged Farmers’ Topsoil. They’re Still Fighting to Build It Back.

EOS - Thu, 04/23/2026 - 12:52

This story was produced by Grist and the Food & Environment Reporting Network, a nonprofit news organization. Sign up for Grist’s weekly newsletter here.

Will Runion’s 736-acre cattle and hay farm is tucked into a horseshoe bend of the Nolichucky River in northeast Tennessee. On the morning of Friday, September 27, 2024, he was in the middle of two big projects: building a riverfront campground on his land to bring in tourists and income, and cutting the last of the season’s hay. Hurricane Helene had been arcing up from Florida toward the Appalachian Mountains, carrying heavy rain, and the river was high. Even though the banks seemed to be holding, he decided to move some of his cows and equipment to higher ground.

But the river kept rising. At about 11 a.m., the brown water topped its banks. He and his fiancée, his son-in-law’s parents, and neighbors scrambled to salvage what farm equipment they could, but they were nearly trapped when the quickly expanding river flowed into a low-lying area behind where they were working, cutting them off from dry land.

By afternoon, the river had swollen to some 1,200 feet wide—nearly 10 times its usual size. It “looked just like a lake,” Runion said. Trees snapped in the swift current and neighbors’ barns, roofs, hay bales, and household debris swirled by. The water swallowed Runion’s hay equipment and sent the little white house he’d planned to use as the new campground’s office sailing across a field.

At around 8 p.m., the Nolichucky finally crested and started to recede. Runion found a third of his fields covered in debris, dead fish, and tomatoes from upstream vegetable growers. The flood had gouged two holes the size of football fields in his hay pastures, down to a depth of 12 feet. Other sections of the farm were buried in up to 8 feet of sand or silt.

Flooding from Hurricane Helene brought massive damage to Will Runion’s farm, eroding the land in some places and washing up feet of sand on agricultural fields in other sections. Courtesy of Bryan LeBarre, via Grist

Helene dropped up to 30 inches of rain on southern Appalachia, causing historic flooding and landslides in parts of North Carolina, South Carolina, Tennessee, Georgia, Kentucky, and Virginia—a largely rural region where agriculture is a vital economic driver and cultural cornerstone. The mountains make it hard to spread out here, so farms tend to be small, and many growers use flood-prone bottomland because it is flat and fertile. But floods of this magnitude hadn’t hit here in generations. In North Carolina alone, Helene caused an estimated $4.9 billion in damage to the state’s agriculture sector. In Tennessee, agricultural losses were estimated at $1.3 billion. Thousands of farmers lost crops, tools, machinery, barns, buildings, animals, and fences.

“When you see 4 feet of sandy soils on top of your topsoil, you know that’s going to be a challenge. That was overwhelming.”

More than a year later, growers are also contending with the loss of something more vital, and more difficult to replace: their soil.

Runion knew immediately that his livelihood was ravaged. Without good soil, a farmer can’t farm. “When you see 4 feet of sandy soils on top of your topsoil, you know that’s going to be a challenge,” he said. “That was overwhelming.”

He sent drone footage of the damage to Forbes Walker, an environmental soil specialist with University of Tennessee Extension. “How do you fix this?” he asked.

“I don’t know,” Walker recalled thinking when he got Runion’s email. “How do we fix this?”

Over millennia, floods helped build the fertile land that farmers depend on. But today, climate change is driving more powerful and unpredictable storms. One study found that rainfall associated with Helene was 10 percent heavier due to man-made climate change. Research by the U.S. National Science Foundation suggests that what scientists call “100-year storms” will become three times more likely, and 20 percent more severe, over the next 50 years. What’s more, there’s little solid information about what happens to soil during a flood, or what to do when a farm’s soil is eroded or covered with material from elsewhere—its nutrients washed away and microbial communities disrupted. It’s a blind spot that is becoming more of a liability as storms like Helene become more common.

“None of us had ever seen anything like this before or responded to an emergency like that,” said Stephanie Kulesza, a nutrient and soil scientist at North Carolina State University. “And so we weren’t really prepared for recommendations to provide to producers.”

Soil can take thousands of years to form. Rock is weathered and slowly dissolves into smaller and smaller pieces. As dead leaves, animals, trees, and other plants decompose, they add organic matter and nutrients to the rock. Microorganisms establish themselves in the mix, driving nutrient cycling, aiding with decomposition, and stimulating plant growth; then worms and bugs, like beetles and ants, burrow in the mixture, aerating it. For soils to work well for agriculture, they need the right structure—airy enough to allow water to enter and move through, but not too quickly or too slowly—and sufficient biological and chemical richness, including nutrients like nitrogen, phosphorous, and potassium, to nourish crops.

Farmers use synthetic or natural fertilizers to ensure their soil has enough nutrients. They can also introduce practices like no-till—farming without plowing up the ground—to maintain the physical properties of their dirt. Topsoil, the rich, uppermost layer with the most available nutrients for crops, tends to make up less than a foot of the entire soil profile, but it’s crucial for agriculture.

Soil scientist Forbes Walker visits Will Runion’s farm in 2025, examining the deep sandy deposits left behind by Hurricane Helene. Credit: Raffe Lazarian/University of Tennessee Institute of Agriculture via Grist

Helene’s floodwaters either washed away significant topsoil or deposited new sediment on top of it on thousands of farms. Some, including one of Runion’s neighbors, saw their fields stripped down to bedrock, or river rock. Runion and others woke to pastures blanketed by feet of sand or stone.

When topsoil is washed away, the necessary nutrients for growing go with it. And when topsoil is covered with sand, farmers can’t get to it. Both scenarios can significantly alter the land’s usability. Topsoil can take decades or centuries to develop, and sand lacks both organic matter and the physical structure to hold water and nutrients. “These aren’t soils yet,” said Kulesza of what Helene left on Runion’s and other farmers’ land. “They are in their infancy now. The clock has been reset.”

Runion had cared for his soils, working to eliminate weeds, adding fertilizer to keep nutrient levels ideal, and lime to control pH. “They were our way of life,” Runion said. “They were our income.”

After the storm, from October to April, he removed debris, bulldozed sand off his fields to get closer to the topsoil, filled holes, and graded uneven land. Crews from the Federal Emergency Management Agency removed and shredded downed trees. He applied for government relief and received close to $1 million in state and federal aid. Runion said he could have easily used all of that money replacing equipment and paying for cleanup labor, fertilizer, and fuel, but he’s trying to stretch the money as much as possible.

By June, it was time to mow the fields that hadn’t flooded. He managed to put up enough bales of hay to feed his herd of 125 cattle, but not enough to sell. In a normal year, hay sales made up about a third of the farm’s income. With months of work behind him and his flooded land still too sandy and generally depleted, he realized the recovery would be a slog.

Runion returned to work on the campground, which he hoped would diversify the family’s earnings. The longer-term plan included a music venue and some hiking trails, and to host weddings and corporate events. After the storm, finishing it took on new urgency. He chose a new spot, about 450 feet upland from the river, and began clearing enough land for 45 camping sites.

One environmental soil specialist described the academic literature on flood-damaged soils as “thin.”

Runion also prepared a parcel of land for Walker, the extension soil specialist, to run tests that could guide his recovery. Last November, soon after the one-year anniversary of Helene, Walker showed me around Runion’s farm.

Working with students, Walker established four experiments over about 300 test plots. He’s looking at how different soil amendments—hay, wood chips, poultry litter, and a charcoal called biochar, to help the soil hold water and fertilizer; and Triple 19, a common plant food with equal parts nitrogen, phosphorous, and potassium—affect the growth of wheat and fescue grasses.

When I visited, some of the plots remained mostly bare while, in others, tufts of green had sprouted. “We actually got some stuff to grow,” Walker said.

He described the academic literature on flood-damaged soils as “thin.” While some research and case studies exist on how agricultural soil recovers after a flood, there are few systematic investigations like the one Walker is conducting—on what works, and what does not—particularly in Appalachia, where floods of this magnitude have been historically rare.

When so-called atmospheric rivers spawned devastating floods in the Pacific Northwest and southwestern British Columbia in 2021, Aimé Messiga, a Canadian soil research scientist at the Agassiz Research and Development Centre, found a similar “scarcity of data.” He conducted a detailed review of the existing research and concluded that there was limited long-term monitoring, little understanding of how floods affect nutrients and microorganism communities in the soil, and uncertainties about what the actual impacts of floods on agriculture and crops are. Complicating everything is the variability between different farms, soils, and crops.

“You need decades of accumulated data in order to be able to predict what will happen. We don’t have those data.”

“You need decades of accumulated data in order to be able to predict what will happen,” Messiga said. “We don’t have those data.”

Today, some researchers are attempting to replicate flood conditions in labs to better understand, but field work is rare, Messiga said. There’s little money for it—and in the U.S., the Trump administration has cut funding for climate-related research. In addition, “many among us still look at these events as random,” Messiga said. “They’re not random. They will keep occurring.”

Since 1980, 45 flooding events have caused damages over $1 billion each in the U.S., with more than half of those occurring in the past 15 years. In 2024, flooding in the upper Midwest drowned crops. Repeat events in central California damaged agricultural operations from winter 2022 to spring 2023. Flooding along the Mississippi River in 2019 reduced crop planting by millions of acres. There also have been numerous smaller or more localized floods. One study found nearly 75,000 flash floods in the contiguous U.S. from 1996 to 2017, with increasing frequency in the past 22 years. Flooding frequency and strength is predicted to rise in the years to come due to climate change—a warmer atmosphere holds more moisture and leads to stronger rain events—and poor land-use management.

Scientists are also starting to study a new type of event, called “weather whiplash,” when sudden changes occur from one extreme to another, amplifying the effects of the disaster. In Texas in 2025, a flood came after prolonged drought, causing widespread destruction.

For farmers, the effects of flooding on soil may linger for years after the disaster. In 2011, the Missouri River flooded states in the Upper Midwest, including thousands of acres of farmland. Fields were swamped for months with up to 20 feet of water. When the water finally receded, those fields were covered with anywhere from 2 to 20 feet of sand; other fields had washed out holes up to 70 feet deep. It looked like the surface of the moon, said John Wilson, a now-retired educator and agricultural expert who served Burt County, Nebraska, which was particularly hard-hit. “It was just bare soil,” he said. “There was no crop residue whatsoever.”

Wilson led teams that sampled the soil and helped farmers build back. He found that levels of nitrogen and organic matter were low in flooded soils, and fertility suffered when farmers planted their crops. Over about five years, fertility generally improved, but not everywhere. “If you went out today and did a yield map, you could still tell exactly where the erosion was because those areas are not as productive,” Wilson said.

Yield is money for farmers, who already navigate thin margins and, often, years without any profit at all. North Carolina’s strategic plan for agriculture recently enumerated just how thin: Of the state’s “42,500 farms, only 8,000 produce annual gross sales that exceed $100,000 annually. The overwhelming majority … some 23,400, gross less than $10,000 in sales, with only around 40 percent of the farms in the state having a positive net income in 2022.”

As floods increasingly wreck farmland, more researchers are starting to focus on understanding the effects of the floods and how to address them. Most of that work is happening in Asia, Messiga said. But a study in coastal North Carolina, where hurricanes regularly land, found that after a storm there was less organic matter in the soil, including carbon, and a disruption of microbial activity and nutrient cycling. The ground also absorbed water less readily.

Coastal flooding is also driving saltwater into the soil of farmland, making it more saline and unable to sustain crops. A North Carolina State University team has been developing test kits for farmers to sample the salinity of their soils, as well as a set of recommendations for keeping their soil viable. Such local work is important because soils vary greatly from place to place, and findings are not often easily transferable.

Nicole DelCogliano’s farm near Asheville, North Carolina, was wiped out almost entirely by floods from Hurricane Helene in 2024. Courtesy of Nicole DelCogliano via Grist

For now, in the wake of Helene, farmers are relying largely on trial and error to build back what was lost. Nicole DelCogliano has been farming vegetables, flowers, and livestock with her husband on 50 acres on the South Toe River, near Asheville, North Carolina, for 25 years. Helene washed away her barn, tractor, and other infrastructure. Of her 6 acres of vegetable fields, one was covered with several feet of sand, another got a foot, and a third field suffered extensive erosion.

“Our entire operation was wiped out, essentially,” she said.

“It’s not something that can be fixed overnight. This is a long process.”

With the help of some friends with tractors, DelCogliano cleared her main field and spread compost and lime on everything. “There was a mix of guidance about what you should do, like should you disturb the soil, should you not?” she said. “At an instinctual level, we just felt like we got to get the soil covered, we got to get something in the ground.” They sowed rye, a dependable cool season grass, as a cover crop, to protect the soil from erosion and add nutrients.

Karen Blaedow, an agricultural educator in Henderson County, North Carolina, said farmers should expect to put in at least three years of cover cropping before they see results in their soil. “It’s not something that can be fixed overnight,” she said. “This is a long process.”

In the spring following the flood, DelCogliano spread various amendments on her least-damaged field, including compost, lime, biochar, and blood and bone meal, which provide nitrogen and phosphorus, respectively. After all that, she and her husband seeded crops.

Their new vegetables came in about two weeks later than normal, but the season was more productive than ever, even though they grew on just 4 instead of 6 acres—“which is pretty amazing,” she said. “When we first started harvesting crops [after Helene], we didn’t yet have power at the farm. I had to dig one of our sinks out of a bank and bleach it and clean it and drag it up to the new barn—that we barely got a roof on—to wash and pack for that first [farmers] market.”

She doesn’t really know what made the year so productive. They planted more intensively to account for the smaller acreage and were able to harness their years of expertise to restart their operation basically from scratch. She also attributes the relative health of her soil to years of organic practices. “We’re dirt farmers,” she said. “Our primary job is to tend the dirt. Because that’s the basis of everything.”

Some farmers who’ve seen good harvests may have gotten a little lucky. Rather than sand, floods dumped silt. Even Runion got silt deposits in one section of his farm. Unlike the sand, the silty layers carry nutrients and create a positive growing environment. “We have a producer we work with and he said it’s the most fertile soil that he’s had in decades,” said Emine Fidan, a biosystems engineering and soil science researcher at the University of Tennessee, who’s also working on Runion’s farm. “And he said it grew the sweetest corn he’s ever had. It was growing just beautifully.”

Runion didn’t plant anything until this past fall. He prepared about 65 acres of the 220 that were underwater. It was slow going; he used a disking machine to till his land but had to stop often to clear sticks and trash and to grade out low spots. He mixed in mulch and planted oats, wheat, and fescue. Walker drove me past one of the fields and it still looked sandy, the grasses just a pale green shadow on the tan land. Runion said the greenery was “struggling to have any vigor about it.” He won’t know for sure how well or poorly the grasses do until spring, their peak growing season.

He considered planting more acreage but decided to wait and see what he learned from Walker’s trials. “It’s a process, and the knowledge we’re gaining there will help on the whole rest of it, too,” Runion said.

This spring, Walker’s team will measure the biomass in each plot as well as the quality of the crop, including how much protein it has and its digestibility. They’ll also be evaluating the soil itself, including its ability to hold water, to determine if any of the treatments improved the structure of the sandy dirt.

One farmer thinks the hay he’ll get in the coming years will be lower-yielding, lower-quality, and will cost more to produce due to the extra prep time, new seeds, and fertilizers.

Preliminary results suggest that, in plots where they put down mulch, the grasses are growing better than in plots with other amendments. The woody debris is reducing erosion and seeds are germinating well and standing up in the rough matrix. Spreading this kind of mulch isn’t an obvious solution, Walker said: Wood chips are a carbon-rich material, but as they break down in the soil they consume nitrogen, which can lead to a deficiency for the crops. But this mulch had sat in piles and started to decompose before it was applied to Runion’s fields, which made it less likely to cause these problems.

Runion had asked FEMA to leave the piles of wood chips on his farm rather than remove them like they normally would. Walker is looking for solutions to the soil problem that not only work but are also accessible. Have a mountain of mulch? Put it to work. Have nearby chicken houses? Maybe their nitrogen-rich manure can help revive flooded fields. His hope is that his team’s research can provide some guidance to farmers who find themselves in similar situations in the future. “I think it will have broad implications for a number of different crops,” including vegetables, Walker said.

Meanwhile, Runion is coming to terms with his situation. He thinks the hay he’ll get in the coming years will be lower-yielding, lower-quality, and will cost more to produce due to the extra prep time, new seeds, and fertilizers. He used to sell a lot of square bales, which tend to contain high-quality grasses and fetch a higher price, but he doesn’t expect to be doing that for a while. He’d initially hoped to have his land back in shape in a year or two. “Now it’s a four- to five-year [plan], I think,” Runion said. “It has been frustrating, and exhausting, too.”

He’s still optimistic, though. On my visit, I watched him grade out the new campground in a large dump truck. Freshly exposed red soil lay open to the sky. He thinks he can get the campground open by late summer or early fall. Over time, he hopes, it will be a more lucrative, and more sustainable, source of income. “The farm is really beautiful,” Runion said. “It still has a lot to offer.”

—Irina Zhorov, Grist

This article originally appeared in Grist at https://grist.org/extreme-weather/hurricane-helene-ravaged-farmers-topsoil-theyre-still-fighting-to-build-it-back/.

Grist is a nonprofit, independent media organization dedicated to telling stories of climate solutions and a just future. Learn more at Grist.org

Gravity Waves Help Drive Sediment to the Deep Ocean

EOS - Thu, 04/23/2026 - 12:00
Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Earth Surface

Turbidity currents are underwater currents that transport sediment on the sea floor. They were first observed in the late 1800s in Lake Geneva, Switzerland. The cable break following the 1929 Grand Banks earthquake offshore Canada revealed how massive and destructive these fluxes can be.

Turbidity currents move downslope because they have a higher density than the surrounding water due to the presence of sediment in suspension. It is critical to keep in mind that suspended sediment concentration in these flows is low, meaning that the fluid is Newtonian and the flow is turbulent.

Notwithstanding recent advances in field monitoring, measuring turbidity current thickness, velocity, suspended sediment concentration, and grain size distribution remains difficult not only for the high-water depths and the destructive nature of some events, but also because these flows are often infrequent. Laboratory experiments and mathematical modeling have been used extensively to understand nature and some aspects of these flows, but questions remain on, for example, how turbidity currents interact with ocean waves, if they do.

Daniller-Verghese et al. [2026] performed laboratory experiments to determine if and how turbidity currents interact with ocean gravity waves. Experimental flows were released in an 11-meter-long, 1.2-meter-deep, and 0.61-meter-wide flume in the Experimental Sedimentation Laboratory of the Jackson School of Geoscience at the University of Texas. A motored wave maker was installed at the downstream end of the facility to generate the wave field. During the experiments, detailed velocity measurements were conducted to characterize the flow field and the fine details of the turbulent fluctuations. At the end of each experiment, high-resolution measurements of changes in bed elevations allowed the quantification of the net depositional fluxes.

The results show that, in presence of a superimposed wave field, the center of deposition volume shifted downstream compared to experiments conducted with the same inflow but in absence of waves. In addition, velocity measurements indicate that the wave signal is stronger in presence of turbidity currents compared to the “clear water” case. In other words, current velocity was larger when waves were present, enhancing downslope sediment transport and causing the observed downstream shift of the center of deposition.

Although the physical mechanism responsible for the observed increase of sediment transport rates in presence of a superimposed wave field still needs to be resolved, these results provide novel insight for the interpretation of storm and turbidity current deposits in the rock record. They also highlight the importance of considering wave-turbidity current interactions to constrain sediment budgets on continental shelves, which are essential to preserve and manage coastlines worldwide.

Citation: Daniller-Varghese, M., Smith, E., Mohrig, D., & Myrow, P. (2026). Wave-signal entrainment into combined flows: Consequences for sediment transport, signal dislocation, and turbulence. Journal of Geophysical Research: Earth Surface, 131, e2025JF008497. https://doi.org/10.1029/2025JF008497

—Enrica Viparelli, Associate Editor, JGR: Earth Surface

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.

In Eastern Africa, the cradle of humankind is tearing apart

Phys.org: Earth science - Thu, 04/23/2026 - 09:00
Eastern Africa's Turkana Rift is both a hotbed for fossil discoveries of our earliest ancestors and a literal hotbed of volcanic activity caused by shifting tectonic plates. Now researchers have found that Earth's underlying crust in the region has been significantly thinned, presaging Africa's eventual breakup—and with that finding, the researchers offer a new perspective on how Turkana's world-famous fossil record of human evolution came to be. The findings are published in Nature Communications.

Geodetic Data Fusion using Multi-Output Sparse Gaussian Processes

Geophysical Journal International - Thu, 04/23/2026 - 00:00
SummaryGeodetic measurements of ground deformation are crucial to identifying and interpreting geophysical processes. We develop a method to fuse data streams from multiple geodetic techniques into a single, three-component deformation field with quantified uncertainties, and without invoking a geophysical model. The fusion is formulated as a semi-parametric latent factor model: a linear mapping ties each observation to the underlying 3-D displacement, while the displacement components are represented nonparametrically with multi-output Gaussian process priors. To achieve practical performance at regional scale, we deploy two complementary sparse GP engines: an Informative Vector Machine (IVM) that selects a small, most-informative active set for fast subset-of-data inference, and a Sparse Variational GP (SVGP) that summarizes the full dataset with inducing points and optimizes a global variational bound. Together, these reduce the scaling of the computation to near-linear in data size and cubic only in the active/inducing set, enabling the potential of fusion of dense geodetic data while maintaining rigorous uncertainty quantification. We demonstrate the approach on coseismic deformation from the 2020 Sparta, NC, USA and 2016 Meinong, Taiwan earthquakes, fusing interferometric synthetic aperture radar (InSAR) with either light detection and ranging (LiDAR) or global navigation satellite system (GNSS) data, respectively. The fused solutions show marked improvements in the precision and coherence of the resolved deformation field and deliver robust, spatially explicit uncertainty estimates. The methodology is readily extensible to time-varying observations to produce four-dimensional (space-time) deformation fields, offering a scalable path to richer characterization of transient geophysical phenomena.

Analysis of the 2019 Mw 6.4 Durrës, Albania, aftershock sequence: Basement involved thrusting at the eastern Adriatic plate margin

Geophysical Journal International - Thu, 04/23/2026 - 00:00
SummaryThe 2019 Mw 6.4 Durrës earthquake in Albania caused severe loss of life and economic damage, highlighting the seismic hazard along the Adriatic–European plate boundary. This study provides the first high-resolution analysis of the aftershock sequence based on data from a dense local seismic network deployed three weeks after the mainshock. Using machine-learning detection and phase-picking tools, we identified 19 152 aftershocks (Ml − 1.8 to 4.6; Mc ≈ 1) over a nine-month period. Based on a newly derived 1D velocity model with station corrections, accounting for large vertical and lateral velocity variations, we relocated the events applying cross-correlation based differential travel times and the double-difference algorithm. The refined seismicity images clearly reveal several sub-parallel ∼30° NE-dipping blind fault structures; the most prominent one, between 12 and 18 km depth, probably hosted the Durrës mainshock. The blind thrust faults lie beneath thick sediments and cut through a carbonate platform and into the Adriatic basement, indicating thick-skinned deformation. Our observations may be interpreted as incipient large-scale slicing and underplating of subducted Adriatic crust. Additional shallow seismicity within a duplex structure in the hanging wall points is relevant for seismic hazard, as even a relatively moderate earthquake occurring close to the surface could cause significant damage.

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