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The deep ocean can often look like a real-life snow globe. As organic particles from plant and animal matter on the surface sink downward, they combine with dust and other material to create "marine snow," a beautiful display of ocean weather that plays a crucial role in cycling carbon and other nutrients through the world's oceans.

Now, researchers from Brown University and the University of North Carolina at Chapel Hill have found surprising new insights into how particles sink in stratified fluids like oceans, where the density of the fluid changes with depth. In a study published inProceedings of the National Academy of Sciences, they show that the speed at which particles sink is determined not only by resistive drag forces from the fluid, but by the rate at which they can absorb salt relative to their volume.

"It basically means that smaller particles can sink faster than bigger ones," said Robert Hunt, a postdoctoral researcher in Brown's School of Engineering who led the work. "That's exactly the opposite of what you'd expect in a fluid that has uniform density."

The researchers hope the new insights could aid in understanding the ocean nutrient cycle, as well as the settling of other porous particulates including microplastics.

"We ended up with a pretty simple formula where you can plug in estimates for different parameters — the size of the particles or speed at which the liquid density changes — and get reasonable estimates of the sinking speed," said Daniel Harris, an associate professor of engineering at Brown who oversaw the work. "There's value in having predictive power that's readily accessible."

The study grew out of prior work by Hunt and Harris investigating neutrally buoyant particles — those that sink to a certain depth and then stop. Hunt noticed some strange behavior that seemed to be related to the porosity of the particles.

"We were testing a theory under the assumption that these particles would remain neutrally buoyant," Hunt said. "But when we observed them, they kept sinking, which was actually kind of frustrating."

That led to a new theoretical model of how porosity — specifically, the ability to absorb salt — would affect the rate at which they sunk. The model predicts that the more salt a particle can absorb relative to its size, the faster it sinks. That means, somewhat counterintuitively, that small porous particles sink faster than larger ones.

To test the model, the researchers developed a way to make a linearly stratified body of water in which the density of the liquid increased gradually with depth. To do that, they fed a large tub with water sourced from two smaller tubs, one with fresh water and the other with salt water. Controllable pumps from each tub enabled them to carefully control the density profile of the larger tub.

Using 3D-printed molds, the team then created particles of varying shapes and sizes made from agar, a gelatinous material derived from seaweed. Cameras imaged individual particles as they sank.

The experiments confirmed the predictions of the model. For spherical particles, smaller ones tended to sink faster. For thinner or flatter particles, their settling speed was primarily determined by their smallest dimension. That means that elongated particles actually sink faster than spherical ones of the same volume.

The results are surprising, the researchers said, and could provide important insights into how particles settle in more complex ecological settings — either for understanding natural carbon cycling or for engineering ways of speeding up carbon capture in large bodies of water.

"We're not trying to replicate full oceanic conditions," Harris said. "The approach in our lab is to boil things down to their simplest form and think about the fundamental physics involved in these complex phenomena. Then we can work back and forth with people measuring these things in the field to understand where these fundamentals are relevant."

Harris says he hopes to connect with oceanographers and climate scientists to see what insights these new findings might provide.

Other co-authors of the research were Roberto Camassa and Richard McLaughlin from UNC Chappel Hill. The research was funded by the National Science Foundation (DMS-1909521, DMS-1910824, DMS-2308063) and the Office of Naval Research (N00014-18-1-2490 and N00014-23-1-2478).

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To reduce greenhouse gas emissions and combat climate change, the world urgently needs clean and renewable energy sources. Hydrogen is one such clean energy source that has zero carbon content and stores much more energy by weight than gasoline. One promising method to produce hydrogen is electrochemical water-splitting, a process that uses electricity to break down water into hydrogen and oxygen. In combination with renewable energy sources, this method offers a sustainable way to produce hydrogen and can contribute to the reduction of greenhouse gases.

Unfortunately, large-scale production of hydrogen using this method is currently unfeasible due to the need for catalysts made from expensive rare earth metals. Consequently, researchers are exploring more affordable electrocatalysts, such as those made from diverse transition metals and compounds. Among these, transition metal phosphides (TMPs) have attracted considerable attention as catalysts for the hydrogen generating side of the process, known as hydrogen evolution reaction (HER), due to their favorable properties. However, they perform poorly in the oxygen evolution reaction (OER), which reduces overall efficiency. Previous studies suggest that Boron (B)-doping into TMPs can enhance both HER and OER performance, but until now, making such materials has been a challenge.

In a recent breakthrough, a research team led by Professor Seunghyun Lee, including Mr. Dun Chan Cha, from the Hanyang University ERICA campus in South Korea, has developed a new type of tunable electrocatalyst using B-doped cobalt phosphide (CoP) nanosheets. Prof. Lee explains, "We have successfully developed cobalt phosphides-based nanomaterials by adjusting boron doping and phosphorus content using metal-organic frameworks. These materials have better performance and lower cost than conventional electrocatalysts, making them suitable for large-scale hydrogen production." Their study was published in the journalSmallon March 19, 2025.

The researchers used an innovative strategy to create these materials, using cobalt (Co) based metal-organic frameworks (MOFs). "MOFs are excellent precursors for designing and synthesizing nanomaterials with the required composition and structures," notes Mr. Cha. First, they grew Co-MOFs on nickel foam (NF). They then subjected this material to a post-synthesis modification (PSM) reaction with sodium borohydride (NaBH4), resulting in the integration of B. This was followed up by a phosphorization process using different amounts of sodium hypophosphite (NaH2PO2), resulting in the formation of three different samples of B-doped cobalt phosphide nanosheets (B-CoP@NC/NF).

Experiments revealed that all three samples had a large surface area and a mesoporous structure, key features that improve electrocatalytic activity. As a result, all three samples exhibited excellent OER and HER performance, with the sample made using 0.5 grams of NaH2PO2 (B-CoP0.5@NC/NF) demonstrating the best results. Interestingly, this sample exhibited overpotentials of 248 and 95 mV for OER and HER, respectively, much lower than previously reported electrocatalysts.

An alkaline electrolyzer developed using the B-CoP0.5@NC/NF electrodes showed a cell potential of just 1.59 V at a current density of 10 mA cm-2, lower than many recent electrolyzers. Additionally, at high current densities above 50 mA cm-2, it even outperformed the state-of-the-art RuO2/NF(+) and 20% Pt-C/NF(−) electrolyzer, while also demonstrating long-term stability, maintaining its performance for over 100 hours.

Density functional theory (DFT) calculations supported these findings and clarified the role of B-doping and adjusting P content. Specifically, B-doping and optimal P content led to effective interaction with reaction intermediates, leading to exceptional electrocatalytic performance.

"Our findings offer a blueprint for designing and synthesizing next-generation high-efficiency catalysts that can drastically reduce hydrogen production costs," says Prof. Lee. "This is an important step towards making large-scale green hydrogen production a reality, which will ultimately help in reducing global carbon emissions and mitigating climate change.

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Plants and trees extend their roots into the earth in order to draw nutrients and water from the soil — however, these roots are thought to decline as they move deeper underground. But a new study by a multi-institutional team of scientists shows that many plants develop a second, deeper layer of roots — often more than three feet underground — to access additional nourishment.

Published in the journalNature Communications,the study reveals previously unrecognized rooting patterns, altering our understanding of how ecosystems

respond to changing environmental conditions. More importantly, the study suggests that plants might transport and store fixed carbon deeper than currently thought — welcome news at a time when CO2 levels are at an 800,000-year high, according to the World Meteorological Organization's "State of the Global Climate Report" issued in March.

"Understanding where plants grow roots is vital, as deeper roots could mean safer and longer-term carbon storage. Harsher conditions at depth may prevent detritus-feeding microbes from releasing carbon back to the atmosphere," says Mingzhen Lu, an assistant professor at New York University's Department of Environmental Studies and the paper's lead author. "Our current ecological observations and models typically stop at shallow depths; by not looking deep enough, we may have overlooked a natural carbon storage mechanism deep underground."

The research team used data from the National Ecological Observatory Network (NEON) to examine rooting depth. The NEON database includes samples collected from soil 6.5 feet below the surface, far deeper than the one-foot depth of traditional ecological studies. This unprecedented depth allowed researchers to detect additional root patterns, spanning diverse climate zones and ecosystem types from the Alaskan tundra to Puerto Rico's rainforests.

The scientists' work focused on three questions — all with the aim of better understanding plants' resource acquisition strategies and their resilience in response to environmental change:

The researchers found that nearly 20 percent of the studied ecosystems had roots that peaked twice across depth — a phenomenon called "bimodality." In these cases, plants developed a second, deeper layer of roots, often more than three feet underground and aligning with nutrient-rich soil layers.This suggests that plants grew — in previously unknown ways — to exploit additional sustenance.

"The current understanding of roots is literally too shallow. Above ground, we have eagle vision — thanks to satellites and remote sensing. But below ground, we have mole vision," observes Lu, former Omidyar Fellow who conducted part of this research at the Sante Fe Institute and as a postdoctoral affiliate at Stanford University. "Our limited below ground vision means that we cannot estimate the full ability of plants to store carbon deep in the soil."

"Deep plant roots may cause increased soil carbon storage in one condition or lead to losses in other conditions due to a stimulation of soil microbes," suggests coauthor Avni Malhotra, the lead author of a companion study that investigated the connection between root distribution and soil carbon stock. "This discovery opens a new avenue of inquiry into how bimodal rooting patterns impact the dynamics of nutrient flow, water cycling, and the long-term capacity of soils to store carbon."

"Scientists and policymakers need to look deeper beneath the Earth's surface as these overlooked deep soil layers may hold critical keys for understanding and managing ecosystems in a rapidly changing climate," concludes Lu. "The good news is plants may already be naturally mitigating climate change more actively than we've realized — we just need to dig deeper to fully understand their potential."

The study also included researchers from Boston College, Columbia University, Dartmouth College, the Morton Arboretum, the National Ecological Observatory Network-Battelle, Pacific Northwest National Laboratory, and Stanford University.

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Scientists at the USC Leonard Davis School of Gerontology have discovered a key connection between high levels of iron in the brain and increased cell damage in people who have both Down syndrome and Alzheimer's disease.

In the study, researchers found that the brains of people diagnosed with Down syndrome and Alzheimer's disease (DSAD) had twice as much iron and more signs of oxidative damage in cell membranes compared to the brains of individuals with Alzheimer's disease alone or those with neither diagnosis. The results point to a specific cellular death process that is mediated by iron, and the findings may help explain why Alzheimer's symptoms often appear earlier and more severely in individuals with Down syndrome.

"This is a major clue that helps explain the unique and early changes we see in the brains of people with Down syndrome who develop Alzheimer's," said Max Thorwald, lead author of the study and a postdoctoral fellow in the laboratory of University Professor Emeritus Caleb Finch at the USC Leonard Davis School. "We've known for a long time that people with Down syndrome are more likely to develop Alzheimer's disease, but now we're beginning to understand how increased iron in the brain might be making things worse."

Down syndrome is caused by having an extra third copy, or trisomy, of chromosome 21. This chromosome includes the gene for amyloid precursor protein, or APP, which is involved in the production of amyloid-beta (Aβ), the sticky protein that forms telltale plaques in the brains of people with Alzheimer's disease.

Because people with Down syndrome have three copies of the APP gene instead of two, they tend to produce more of this protein. By the age of 60, about half of all people with Down syndrome show signs of Alzheimer's disease, which is approximately 20 years earlier than in the general population.

"This makes understanding the biology of Down syndrome incredibly important for Alzheimer's research," said Finch, the study's senior author.

Key findings point to ferroptosis

The research team studied donated brain tissue from individuals with Alzheimer's, DSAD, and those without either diagnosis. They focused on the prefrontal cortex — an area of the brain involved in thinking, planning, and memory — and made several important discoveries:

Together, these findings indicate increased ferroptosis, a type of cell death characterized by iron-dependent lipid peroxidation, Thorwald explained: "Essentially, iron builds up, drives the oxidation that damages cell membranes, and overwhelms the cell's ability to protect itself."

Lipid rafts: a hotspot for brain changes

The researchers paid close attention to lipid rafts — tiny parts of the brain cell membrane that play crucial roles in cell signaling and regulate how proteins like APP are processed. They found that in DSAD brains, lipid rafts had much more oxidative damage and fewer protective enzymes compared to Alzheimer's or healthy brains.

Notably, these lipid rafts also showed increased activity of the enzyme β-secretase, which interacts with APP to produce Aβ proteins. The combination of more damage and more Aβ production may promote the growth of amyloid plaques, thus speeding up Alzheimer's progression in people with Down syndrome, Finch explained.

Rare Down syndrome variants offer insight

The researchers also studied rare cases of individuals with "mosaic" or "partial" Down syndrome, in which the third copy of chromosome 21 is only present in a smaller subset of the body's cells. These individuals had lower levels of APP and iron in their brains and tended to live longer. In contrast, people with full trisomy 21 and DSAD had shorter lifespans and higher levels of brain damage.

"These cases really support the idea that the amount of APP — and the iron that comes with it — matters a lot in how the disease progresses," Finch said.

The team says their findings could help guide future treatments, especially for people with Down syndrome who are at high risk of Alzheimer's. Early research in mice suggests that iron-chelating treatments, in which medicine binds to the metal ions and allows them to leave the body, may reduce indicators of Alzheimer's pathology, Thorwald noted.

"Medications that remove iron from the brain or help strengthen antioxidant systems might offer new hope," Thorwald said. "We're now seeing how important it is to treat not just the amyloid plaques themselves but also the factors that may be hastening the development of those plaques."

The study was supported by the National Institute on Aging, National Institutes of Health (P30-AG066519, R01-AG051521, P50-AG05142, P01-AG055367, R01AG079806, P50-AG005142, P30-AG066530, P30-AG066509, U01-AG006781, T32AG052374, R01AG079806-02S1, and T32-AG000037); Cure Alzheimer's Fund; Simons Collaboration on Plasticity in the Aging Brain (SF811217); Larry L. Hillblom Foundation (2022-A-010-SUP); Glenn Foundation for Medical Research; and the Navigage Foundation Award.

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The idea seems futuristic: At ETH Zurich, various disciplines are working together to combine conventional materials with bacteria, algae and fungi. The common goal: to create living materials that acquire useful properties thanks to the metabolism of microorganisms — "such as the ability to bind CO2from the air by means of photosynthesis," says Mark Tibbitt, Professor of Macromolecular Engineering at ETH Zurich.

An interdisciplinary research team led by Tibbitt has now turned this vision into reality: it has stably incorporated photosynthetic bacteria — known as cyanobacteria — into a printable gel and developed a material that is alive, grows and actively removes carbon from the air. The researchers recently presented their "photosynthetic living material" in a study in the journalNature Communications.

Key characteristic: Dual carbon sequestration

The material can be shaped using 3D printing and only requires sunlight and artificial seawater with readily available nutrients in addition to CO2to grow. "As a building material, it could help to store CO2directly in buildings in the future," says Tibbitt, who co-initiated the research into living materials at ETH Zurich.

The special thing about it: the living material absorbs much more CO2than it binds through organic growth. "This is because the material can store carbon not only in biomass, but also in the form of minerals — a special property of these cyanobacteria," reveals Tibbitt.

Yifan Cui, one of the two lead authors of the study, explains: "Cyanobacteria are among the oldest life forms in the world. They are highly efficient at photosynthesis and can utilize even the weakest light to produce biomass from CO2and water."

At the same time, the bacteria change their chemical environment outside the cell as a result of photosynthesis, so that solid carbonates (such as lime) precipitate. These minerals represent an additional carbon sink and — in contrast to biomass — store CO2in a more stable form.

Cyanobacteria as master builders

"We utilize this ability specifically in our material," says Cui, who is a doctoral student in Tibbitt's research group. A practical side effect: the minerals are deposited inside the material and reinforce it mechanically. In this way, the cyanobacteria slowly harden the initially soft structures.

Laboratory tests showed that the material continuously binds CO2 over a period of 400 days, most of it in mineral form — around 26 milligrams of CO2per gram of material. This is significantly more than many biological approaches and comparable to the chemical mineralization of recycled concrete (around 7 mg CO2per gram).

The carrier material that harbours the living cells is a hydrogel — a gel made of cross-linked polymers with a high water content. Tibbitt's team selected the polymer network so that it can transport light, CO2, water and nutrients and allows the cells to spread evenly inside without leaving the material.

To ensure that the cyanobacteria live as long as possible and remain efficient, the researchers have also optimised the geometry of the structures using 3D printing processes to increase the surface area, increase light penetration and promote the flow of nutrients.

Co-first author Dalia Dranseike: "In this way, we created structures that enable light penetration and passively distribute nutrient fluid throughout the body by capillary forces." Thanks to this design, the encapsulated cyanobacteria lived productively for more than a year, the materials researcher in Tibbitt's team is pleased to report.

Infrastructure as a carbon sink

The researchers see their living material as a low-energy and environmentally friendly approach that can bind CO2from the atmosphere and supplement existing chemical processes for carbon sequestration. "In the future, we want to investigate how the material can be used as a coating for building façades to bind CO2throughout the entire life cycle of a building," Tibbitt looks ahead.

There is still a long way to go — but colleagues from the field of architecture have already taken up the concept and realised initial interpretations in an experimental way.

Two installations in Venice and Milan

Thanks to ETH doctoral student Andrea Shin Ling, basic research from the ETH laboratories has made it onto the big stage at the Architecture Biennale in Venice. "It was particularly challenging to scale up the production process from laboratory format to room dimensions," says the architect and bio-designer, who is also involved in this study.

Ling is doing her doctorate at ETH Professor Benjamin Dillenburger's Chair of Digital Building Technologies. In her dissertation, she developed a platform for biofabrication that can print living structures containing functional cyanobacteria on an architectural scale.

For the Picoplanktonics installation in the Canada Pavilion, the project team used the printed structures as living building blocks to construct two tree-trunk-like objects, the largest around three metres high. Thanks to the cyanobacteria, these can each bind up to 18 kg of CO2per year — about as much as a 20-year-old pine tree in the temperate zone.

"The installation is an experiment — we have adapted the Canada Pavilion so that it provides enough light, humidity and warmth for the cyanobacteria to thrive and then we watch how they behave," says Ling. This is a commitment: The team monitors and maintains the installation on site — daily. Until November 23.

At the 24th Triennale di Milano, Dafne's Skin is investigating the potential of living materials for future building envelopes. On a structure covered with wooden shingles, microorganisms form a deep green patina that changes the wood over time: A sign of decay becomes an active design element that binds CO2and emphasises the aesthetics of microbial processes. Dafne's Skin is a collaboration between MAEID Studio and Dalia Dranseike. It is part of the exhibition "We the Bacteria: Notes Toward Biotic Architecture" and runs until November 9.

The photosynthetic living material was created thanks to an interdisciplinary collaboration within the framework ofALIVE (Advanced Engineering with Living Materials). The ETH Zurich initiative promotes collaboration between researchers from different disciplines in order to develop new living materials for a wide range of applications.

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A University of Queensland-led project has developed a tool to standardize genetic testing of koala populations, providing a significant boost to conservation and recovery efforts.

Dr Lyndal Hulse from UQ's School of the Environment said the standardized koala genetic marker panel provides a consistent method for researchers nationwide to capture and share koala genetic variation, enabling improved collaboration and data integration across studies.

"Koalas in the wild are under increasing pressure from habitat loss, disease and vehicle strikes, forcing them to live in increasingly smaller and more isolated pockets with limited access to breeding mates outside their group," Dr Hulse said.

"Population inbreeding can mean detrimental effects on their health.

"A standardized panel for directly comparing genetic markers enables researchers, conservationists and government agencies to better understand the genetic diversity of koala populations, allowing for greater collaboration to ensure their survival."

Saurabh Shrivastava, Senior Account Manager at project partner the Australian Genome Research Facility (AGRF Ltd), said the new screening tool was a single nucleotide polymorphism (SNP) array that used next-generation sequencing technologies.

"The Koala SNP-array can accommodate good quality DNA, so is suitable for broad-scale monitoring of wild koala populations," Mr Shrivastava said.

"Importantly, it is available to all researchers and managers."

Dr Hulse said ideally the tool could help guide targeted koala relocations across regions.

"There are very strict rules about relocating koalas, but this could be key to improving and increasing the genetics of populations under threat," she said.

"These iconic Australian marsupials are listed as endangered in Queensland, New South Wales and the ACT – and in 50 years we may only be able to see koalas in captivity.

"Understanding the genetic diversity of different populations of koalas is crucial if we're going to save them from extinction."

The project included researchers from the Australasian Wildlife Genomics Group at the University of New South Wales.

AGRF Ltd isanot-for-profit organization advancing Australian genomics through nationwide access to expert support and cutting-edge technology across a broad range of industries including biomedical, health, agriculture and environmental sectors.

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Atmospheric rivers are responsible for most flooding on the West Coast of the U.S., but also bring much needed moisture to the region. The size of these storms doesn't always translate to flood risk, however, as other factors on the ground play important roles. Now, a new study helps untangle the other drivers of flooding to help communities and water managers better prepare.

The research, published June 4 in theJournal of Hydrometeorology, analyzed more than 43,000 atmospheric river storms across 122 watersheds on the West Coast between 1980 and 2023. The researchers found that one of the primary driving forces of flooding is wet soils that can't absorb more water when a storm hits. They showed that flood peaks were 2-4.5 times higher, on average, when soils were already wet. These findings can help explain why some atmospheric river storms cause catastrophic flooding while others of comparable intensity do not. Even weaker storms can generate major floods if their precipitation meets a saturated Earth, while stronger storms may bring needed moisture to a parched landscape without causing flooding.

"The main finding comes down to the fact that flooding from any event, but specifically from atmospheric river storms, is a function not only of the storm size and magnitude, but also what's happening on the land surface," said Mariana Webb, lead author of the study who is completing her Ph.D. at DRI and the University of Nevada, Reno. "This work demonstrates the key role that pre-event soil moisture can have in moderating flood events. Interestingly, flood magnitudes don't increase linearly as soil moisture increases, there's this critical threshold of soil moisture wetness above which you start to see much larger flows."

The study also untangled the environmental conditions of regions where soil moisture has the largest influence on flooding. In arid places like California and southwestern Oregon, storms that hit when soils are already saturated are more likely to cause floods. This is because watersheds in these regions typically have shallow, clay-rich soils and limited water storage capacity. Due to lower precipitation and higher evaporation rates, soil moisture is also more variable in these areas. In contrast, in lush Washington and the interior Cascades and Sierra Nevada regions, watersheds tend to have deeper soils and snowpack, leading to a higher water storage capacity. Although soil saturation can still play a role in driving flooding in these areas, accounting for soil moisture is less valuable for flood management because soils are consistently wet or insulated by snow.

"We wanted to identify the watersheds where having additional information about the soil moisture could enhance our understanding of flood risk," Webb said. "It's the watersheds in more arid climates, where soil moisture is more variable due to evaporation and less consistent precipitation, where we can really see improvements in flood prediction."

Although soil moisture data is currently measured at weather monitoring stations like the USDA's SNOTEL Network, observations are relatively sparse compared to other measures like rainfall. Soil moisture can also vary widely within a single watershed, so often multiple stations are required to give experts a clear picture that can help inform flooding predictions. Increased monitoring in watersheds identified as high-risk, including real-time soil moisture observations, could significantly enhance early warning systems and flood management as atmospheric rivers become more frequent and intense.

By tailoring flood risk evaluations to a specific watershed's physical characteristics and climate, the study could improve flood-risk predictions. The research demonstrates how flood risk increases not just with storm size and magnitude, but with soil moisture, highlighting the value of integrating land surface conditions into impact assessments for atmospheric rivers. "My research really focuses on this interdisciplinary space between atmospheric science and hydrology," Webb said. "There's sometimes a disconnect where atmospheric scientists think about water up until it falls as rain, and hydrologists start their work once the water is on the ground. I wanted to explore how we can better connect these two fields."

Webb worked with DRI ecohydrologist Christine Albano to produce the research, building on Albano's extensive expertise studying atmospheric rivers, their risks, and their impacts on the landscape.

"While soil saturation is widely recognized as a key factor in determining flood risk, Mari's work helps to quantify the point at which this level of saturation leads to large increases in flood risk across different areas along the West Coast," Albano said. "Advances in weather forecasting allow us to see atmospheric rivers coming toward the coast several days before they arrive. By combining atmospheric river forecast information with knowledge of how close the soil moisture is to critical saturation levels for a given watershed, we can further improve flood early warning systems."

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A cosmic particle detector in Antarctica has emitted a series of bizarre signals that defy the current understanding of particle physics, according to an international research group that includes scientists from Penn State. The unusual radio pulses were detected by the Antarctic Impulsive Transient Antenna (ANITA) experiment, a range of instruments flown on balloons high above Antarctica that are designed to detect radio waves from cosmic rays hitting the atmosphere.

The goal of the experiment is to gain insight into distant cosmic events by analyzing signals that reach the Earth. Rather than reflecting off the ice, the signals — a form of radio waves — appeared to be coming from below the horizon, an orientation that cannot be explained by the current understanding of particle physics and may hint at new types of particles or interactions previously unknown to science, the team said.

The researchers published their results in the journal Physical Review Letters.

"The radio waves that we detected were at really steep angles, like 30 degrees below the surface of the ice," said Stephanie Wissel, associate professor of physics, astronomy and astrophysics who worked on the ANITA team searching for signals from elusive particles called neutrinos.

She explained that by their calculations, the anomalous signal had to pass through and interact with thousands of kilometers of rock before reaching the detector, which should have left the radio signal undetectable because it would have been absorbed into the rock.

"It's an interesting problem because we still don't actually have an explanation for what those anomalies are, but what we do know is that they're most likely not representing neutrinos," Wissel said.

Neutrinos, a type of particle with no charge and the smallest mass of all subatomic particles, are abundant in the universe. Usually emitted by high-energy sources like the sun or major cosmic events like supernovas or even the Big Bang, there are neutrino signals everywhere. The problem with these particles, though, is that they are notoriously difficult to detect, Wissel explained.

"You have a billion neutrinos passing through your thumbnail at any moment, but neutrinos don't really interact," she said. "So, this is the double-edged sword problem. If we detect them, it means they have traveled all this way without interacting with anything else. We could be detecting a neutrino coming from the edge of the observable universe."

Once detected and traced to their source, these particles can reveal more about cosmic events than even the most high-powered telescopes, Wissel added, as the particles can travel undisturbed and almost as fast as the speed of light, giving clues about cosmic events that happened lightyears away.

Wissel and teams of researchers around the world have been working to design and build special detectors to capture sensitive neutrino signals, even in relatively small amounts. Even one small signal from a neutrino holds a treasure trove of information, so all data has significance, she said.

"We use radio detectors to try to build really, really large neutrino telescopes so that we can go after a pretty low expected event rate," said Wissel, who has designed experiments to spot neutrinos in Antarctica and South America.

ANITA is one of these detectors, and it was placed in Antarctica because there is little chance of interference from other signals. To capture the emission signals, the balloon-borne radio detector is sent to fly over stretches of ice, capturing what are called ice showers.

"We have these radio antennas on a balloon that flies 40 kilometers above the ice in Antarctica," Wissel said. "We point our antennas down at the ice and look for neutrinos that interact in the ice, producing radio emissions that we can then sense on our detectors."

These special ice-interacting neutrinos, called tau neutrinos, produce a secondary particle called a tau lepton that is released out of the ice and decays, the physics term referring to how the particle loses energy as it travels over space and breaks down into its constituents. This produces emissions known as air showers.

If they were visible to the naked eye, air showers might look like a sparkler waved in one direction, with sparks trailing it, Wissel explained. The researchers can distinguish between the two signals — ice and air showers — to determine attributes about the particle that created the signal.

These signals can then be traced back to their origin, similar to how a ball thrown at an angle will predictably bounce back at the same angle, Wissel said. The recent anomalous findings, though, cannot be traced back in such a manner as the angle is much sharper than existing models predict.

By analyzing data collected from multiple ANITA flights and comparing it with mathematical models and extensive simulations of both regular cosmic rays and upward-going air showers, the researchers were able to filter out background noise and eliminate the possibility of other known particle-based signals.

The researchers then cross-referenced signals from other independent detectors like the IceCube Experiment and the Pierre Auger Observatory to see if data from upward-going air showers, similar to those found by ANITA, were captured by other experiments.

Analysis revealed the other detectors did not register anything that could have explained what ANITA detected, which led the researchers to describe the signal as "anomalous," meaning that the particles causing the signal are not neutrinos, Wissel explained. The signals do not fit within the standard picture of particle physics, and while several theories suggest that it may be a hint of dark matter, the lack of follow-up observations with IceCube and Auger really narrow the possibilities, she said.

Penn State has built detectors and analyzed neutrino signals for close to 10 years, Wissel explained, and added that her team is currently designing and building the next big detector. The new detector, called PUEO, will be larger and better at detecting neutrino signals, Wissel said, and it will hopefully shed light on what exactly the anomalous signal is.

"My guess is that some interesting radio propagation effect occurs near ice and also near the horizon that I don't fully understand, but we certainly explored several of those, and we haven't been able to find any of those yet either," Wissel said. "So, right now, it's one of these long-standing mysteries, and I'm excited that when we fly PUEO, we'll have better sensitivity. In principle, we should pick up more anomalies, and maybe we'll actually understand what they are. We also might detect neutrinos, which would in some ways be a lot more exciting."

The other Penn State co-author is Andrew Zeolla, a doctoral candidate in physics. The research conducted by scientists from Penn State was funded by the U.S. Department of Energy and the U.S. National Science Foundation. The paper contains the full list of collaborators and authors.

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Mycorrhizal fungi help regulate Earth's climate and ecosystems by forming underground networks that provide plants with essential nutrients, while drawing carbon deep into soils. Scientists and conservationists have been racing to find ways to protect these underground fungi, but they keep finding dark taxa – species that are known only by their DNA sequences that can't be linked to named or described species.

It is estimated that only 155,000 of the roughly 2-3 million fungal species on the planet have been formally described. Now, a review published inCurrent Biologyon June 9 shows that as much as 83% of ectomycorrhizal species are so-called dark taxa. The study helps identify underground hotspots of unknown mycorrhizal species occurring in tropical forests in southeast Asia and Central and South America, tropical forests and shrublands in central Africa, Sayan montane conifer forests above Mongolia, and more. This discovery has serious implications for conservation.

Names are important in the natural sciences. Traditionally, once a species is described, it is given a binomial – a name made of two Latin words that describe the species and genus. These names are used to categorize fungi, plants, and animals, and are critical identifiers for conservation and research. Most mycorrhizal fungi in the wild are found using environmental DNA (eDNA) — genetic material that organisms shed into their surroundings. Scientists extract fungal eDNA from soil and root samples, sequence that DNA, and then run those sequences through a bioinformatics pipeline that matches a sequence with a described species. For dark taxa there are no matches – just strings of As, Gs, Cs, and Ts.

"We are a long way out from getting all fungal DNA sequences linked to named species," says lead author Laura van Galen, a microbial ecologist working with the Society for the Protection of Underground Networks (SPUN) and ETH University, Switzerland. "Environmental DNA has enormous potential as a research tool to detect fungal species, but we can't include unnamed species in conservation initiatives. How can you protect something that hasn't yet been named?"

Ectomycorrhizal fungi are one of the largest groups of mycorrhizal fungi and form symbiotic partnerships with about 25% of global vegetation. Ectomycorrhizal fungi facilitate the drawdown of over 9 billion tons of CO2annually (over 25% of yearly fossil fuel emissions) and help Earth's forests function by regulating nutrient cycles, enhancing stress tolerance, and even breaking down pollutants.

The researchers' work has uncovered that dark taxa of ectomycorrhizal fungi are not spread evenly across the Earth. "There are hotspots of high dark taxa around the globe, but particularly they are concentrated in tropical regions in Southeast Asia and parts of South America and Africa," says van Galen. "Most of the research on ectomycorrhizal fungi has been focused in the North, but mid-latitude and southern-hemisphere regions show signs of being home to many unknown species. This means there is a mismatch in resources and funding. We need to bridge this gap and facilitate more tropical researchers and those from southern-hemisphere regions to focus on identifying these super-important fungi."

The researchers have suggestions of how we can start bringing these fungi out of the shadows. "One way to reduce the dark taxa problem is to collect, study and sequence mushrooms and other fungi," says co-author Camille Truong, a mycorrhizal ecologist at SPUN and research scientist at the Royal Botanic Gardens Victoria in Australia. "Conversely, there are mushrooms that have been sitting for decades in collections of botanical gardens. These should be urgently sequenced so that we can, hopefully, start matching them up with some of these dark taxa."

Many of the unidentified fungal species are associated with plants that are themselves endangered. "We're at risk here," says van Galen. "If we lose these host plants, we might also be losing really important fungal communities that we don't know anything about yet."

The technology is available – what's missing is attention. "We really need to pay so much more attention to fungi in the soil so that we can understand the species and protect them and conserve them before we lose them," says van Galen. The team hopes that conservation organizations will use the information to protect hotspots of underground biodiversity, even if these species remain nameless.

Materialsprovided bySPUN (Society for the Protection of Underground Networks).Note: Content may be edited for style and length.

Scientists have shed new light on the evolution of an important species of wasp – and believe that the findings could help improve the effectiveness of natural pest control.

Dr Rebecca Boulton, from the University of Stirling, has shown, for the first time, thatLysiphlebus fabarum- a tiny species of wasp – can reproduce with or without a mate. This discovery challenges the previous assumption that asexual females could not mate and produce offspring sexually.

Significantly, the wasps lay their eggs inside small sap-sucking insects called aphids before consuming their host from the inside out — meaning that they are natural pest controllers.

Lysiphlebus fabarumis known to have both sexual and asexual populations but, until now, it was not known whether asexual females could reproduce sexually with males. The discovery opens up new possibilities for improving biological pest control.

Many species of parasitoid wasps are mass-reared and released as a natural alternative to pesticides because they lay their eggs on or in other species, many of which are pests, before the developing wasp larvae consumes their host, killing it in the process.

Asexual reproduction makes it easy to produce large numbers of wasps, but these need to be suitably adapted to local pests and environments to be effective. Currently,Lysiphlebus fabarumis not used commercially despite being found worldwide and naturally targeting aphids.

Developing an understanding of how the species reproduce could help boost genetic diversity in commercially reared lines, making future biocontrol agents more resilient and better adapted.

Dr Boulton, a lecturer in Biological and Environmental Sciences at the University's Faculty of Natural Sciences, led the study. She said: "In an evolutionary sense, facultative sex seems like a perfect strategy – asexual reproduction is highly efficient, and takes away the costs of finding a mate as well as the risks of failing to find one.

"But sex is really important for evolution. When females reproduce asexually they don't mix their genes up with any others which limits the potential for evolution to happen.

"If the environment changes, asexual species may be unable to adapt in the same way that sexuals can.

"Facultative sex brings the efficiency of asexual reproduction with the evolutionary benefits of sex and so has been touted as the best of both worlds.

"The results of my study show that there might be hidden costs to facultative sex though as it reduces female wasps' reproductive success, and this might limit how frequently it occurs in nature.

"The wasps that I studied are an important natural enemy of aphids, they aren't currently commercially reared, but they are found globally.

"My findings could be used to develop new biocontrol agents that can be used to control aphids throughout the world, harnessing their natural reproductive behavior to ensure that they are adapted to the hosts and environments that are specific to different regions."

Dr Boulton reared the wasps in a Controlled Environment Facility (CEF) at the University and had initially planned to put asexual and sexual wasps together, in direct competition, to see which parasitized the most aphids.

However, in the early stages of these experiments she realized the female asexual wasps were behaving unexpectedly and were mating with males from the sexual population.

This led to a change in strategy, as she started to record this behavior in more detail, before carrying out wasp paternity testing to see whether the asexual females were just mating or actually fertilizing eggs.

Once it confirmed that the asexual wasps were engaging in facultative sex, Dr Boulton carried out an experiment where asexual females either mated or didn't, before examining how successful these females, and their daughters, were at parasitizing aphids.

The study involved putting around 300 wasps, each around 1mm long, in their own petri dish with a colony of sap-sucking aphids and counting how many were parasitized.

Lysiphlebus fabarumwasps only live a few days but spend two weeks developing as larvae on their hosts.

The entire experiment, which was carried out across two generations of wasps, took six weeks to run.

On completion Dr Boulton extracted DNA from the wasps and sent it to be paternity tested. When the results were returned it was clear that the asexual wasps which mated were, in most cases, reproducing sexually as their offspring had bits of DNA that were only found in the fathers.

The study, Is facultative sex the best of both worlds in the parasitoid wasp Lysiphlebus fabarum? is published in the Royal Society of Open Science.

It was funded through a BBSRC Discovery fellowship.

Professor Anne Ferguson-Smith, Executive Chair of BBSRC, said: "This is an exciting example of how BBSRC's Discovery Fellowships are helping talented early career researchers explore fundamental questions in bioscience with real-world relevance.

"Dr Boulton's work, which measures the costs of sex in this predominantly asexual parasitoid wasp, opens up promising avenues for more sustainable pest control. Supporting curiosity-driven research like this not only strengthens the UK's research base, but helps drive innovation that benefits the environment, food systems and society at large."

Materialsprovided byUniversity of Stirling.Note: Content may be edited for style and length.