If you’ve ever swum in the ocean and been touched by seaweed, there’s a good chance it was Sargassum! This free-floating seaweed can have population explosions in coastal waters, degrading water quality, ecosystems, fisheries, and tourism. However, despite its drawbacks, scientists think that Sargassum could be useful for extracting valuable metals, known as rare earth elements (REEs). 

REEs are classified by their average masses and atomic weights. Light REEs include cerium, praseodymium, and neodymium, middle REEs include gadolinium, terbium, and dysprosium, and heavy REEs include erbium, thulium, and ytterbium. These metals are used in magnets, electronic motors, wind turbines, spacecraft, and more. Our current methods of extracting REEs, open-pit mining and chemical processing, are invasive, causing habitat loss and producing toxic waste. Additionally, REEs are difficult to import due to restricted access worldwide. But what if these metals could be extracted using natural methods? 

Scientists from Woods Hole and UCLA recently tested whether Sargassum could accumulate REEs, creating a sustainable solution to these problems. They harvested Sargassum at Waterfront Park in Woods Hole, rinsed the wet samples, and stored them in sterilized, filtered seawater, which they aerated with 12-hour cycles of light and dark to keep the Sargassum alive. They dried another set of samples in the sun under controlled outdoor conditions, stored them in sealed containers, and later rehydrated them in seawater for 3 hours before the experiments.

For each experiment, they added 5 grams (about 0.2 ounces) of Sargassum to solutions containing a mixture of 9 REEs – cerium, praseodymium, neodymium, gadolinium, terbium, dysprosium, erbium, thulium, and ytterbium – in concentrations totalling 0.1 micromolar (μM) REEs, 11μM REEs, 100 to 110μM REEs, and 575 to 600μM REEs. They performed each experiment 4 times: twice with fresh seaweed and twice with rehydrated seaweed. 

The researchers removed 1 gram (about 0.04 ounces) of seaweed from each solution after 1, 3, and 7 days, and dissolved it in acid to release the REEs it had absorbed. They analyzed the concentrations of REEs in each seaweed sample and the leftover solutions using 2 different plasma-based methods. They used these REE concentrations to calculate the ratio of REEs in the Sargassum versus in the solution, known as the bioconcentration factor, to determine how effectively the seaweed absorbed REEs. 

They found that after 7 days at lower REE concentrations (0.1μM), the fresh seaweed had bioconcentration factors of over 1,000. At higher REE concentrations (11μM), their bioconcentration factors ranged from about 400 to 700. However, these levels of REEs were eventually toxic to the fresh Sargassum, so they died after 2 weeks. In addition, the higher REE concentrations of 100 to 600μM were immediately toxic to the fresh Sargassum, which died within 1 day in solution. 

The researchers determined that once the seaweed died, it could no longer actively take up REEs into its tissues but could only accumulate them on its surface or adsorb them. Adsorption can be thought of as a powdered donut – when the surface is covered with powdered sugar, no more powder fits on the donut. Similarly, there was a limit to how many REEs could stick to the Sargassum. Due to this limit, the fresh seaweed samples had bioconcentration factors below 250 in the highest REE concentrations. In contrast, the rehydrated Sargassum consumed less REEs at lower concentrations, but didn’t experience toxicity and continued to accumulate REEs at higher concentrations.

Finally, the team compared Sargassum to a common industrial method of accumulating REEs, known as activated carbon. REEs bond easily to activated carbon because of its abundant surface area and high porosity. Both materials accumulated a similar amount of REEs in solutions of 0.1μM REEs. However, at 575 to 600μM REEs, Sargassum accumulated about twice as many REEs as activated carbon, especially the heavier REEs. 

​The researchers concluded that Sargassum is a natural hyper-accumulator, meaning it successfully concentrates REEs. However, they recommended that future researchers test whether Sargassum performs the same in the natural environment as it does in the lab. If so, Sargassum could be used to accumulate REEs from wastewater, like mine drainage, or other water sources with higher concentrations of REEs. Regardless, they suggested that using Sargassum to obtain REEs could simultaneously expand global access to these metals and mitigate toxic blooms.

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From Nevada to Manchester, developers are trialling innovative solutions to clean energy’s biggest challenge

In the deserts of the United Arab Emirates a sprawling clean energy project, stretching across an area roughly the size of 12,600 football fields, will play host to a breakthrough allowing solar energy to power the equivalent of half a million homes through the night.

The Gulf state has been steadily combining 5.2GW of solar power capacity with 19GWh of battery storage to create the largest battery scheme in the world.

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© Photograph: UCG/Universal Images Group/Getty Images

© Photograph: UCG/Universal Images Group/Getty Images

© Photograph: UCG/Universal Images Group/Getty Images

Humans have been around for only about 0.01% of Earth’s history, yet we’ve altered natural landscapes and processes that have remained stable for millions of years. A team of researchers from the University of Glasgow recently studied a formerly sandy beach in the UK that highlights how fast these changes can occur.

Industrial steel and iron furnaces operated extensively in the UK from 1856 until the 1980s. During these decades, workers dumped roughly 335 million cubic meters (90 billion gallons) of molten furnace waste, called slag, across the country. Of that, roughly 27 million cubic meters (6 million gallons) now sits on the coast of Derwent Howe in a massive 30-meter (100-foot), solidified cliff. 

The researchers analyzed this region to understand how man-made, or anthropogenic, materials influence the way rocks form. Rocks naturally form and change into different types of rocks over million-year timescales, through a continuous process called the rock cycle. When the team uncovered a soda can tab manufactured in 1989 within the hardened grains, or clasts, of slag, they concluded that the beach had solidified within the last 35 years. Based on this discovery, they proposed a new term for rocks formed from anthropogenic sediments: the anthropoclastic rock cycle. 

The team collected 1,300 grains of sediment from 13 sites in the study area and found that 83% were slag. Natural beach sediments, like quartz sand, comprised only about 17% of the grains. As wind and waves broke down the cliff, slag clasts fell off and became rounded by friction as tides transported them from the cliff to the beach. 

At the boundary where the slag touched the beach, the researchers also saw evidence that the slag had seeped into the underlying wet sediment. The rocks there resembled a type of rock called peperite, which forms when lava flows over wet, loose sediments.  They concluded that this peperite-like rock formed as the molten slag flowed over the still sandy beach. Slag is much thicker than wet sand, so the resulting rock looked like blobs of slag encased in sandy rock. 

The researchers then visually observed how the slag grains were arranged in the solidified rock to reconstruct the tidewater speeds at different points in the coast’s history. The different ways sediments are arranged within a rock are called sedimentary features, and they reflect the processes that formed the rock. For example, as water flows over sand, it forms small, dune-like ripples. When the sand beds harden into rock, the ripples are preserved as features known as trough cross-bedding. 

Faster water erases any ripple formations and instead forms horizontal layers in the sediment, known as planar lamination. The researchers observed both trough cross-bedding and planar laminations preserved in the slag beach rocks. These sedimentary features indicate that the beach at Derwent Howe turned from loose sediment into rock in a generation. 

To investigate why this beach rapidly solidified, the researchers scanned the surfaces of the beach rock with electron beams and X-rays using a scanning electron microscope, or SEM, equipped with an energy dispersive X-ray, or EDX. Every chemical element emits a unique set of X-rays with different wavelengths when hit with EDX, so the researchers could compare the X-rays from their samples to databases of known mineral X-ray signatures. They identified the primary binding agents as calcium- and iron-rich minerals like calcite, goethite, and brucite. These minerals are called cements because they bind grains of sediment together. 

The researchers expected the slag to produce these cement compositions, since extracting metal ores from rock enriches the resultant slag in calcium, magnesium, manganese, and iron, which readily dissolve in water. When water flowing between closely packed slag grains can no longer hold additional dissolved elements, those elements precipitate as solid mineral cements. Since cements only form when the water has very high concentrations of dissolved elements, the introduction of massive amounts of slag caused the cement to form faster than it would in waters with lower concentrations of elements.

The researchers suspected that the anthropoclastic rock cycle they observed at Derwent Howe is not uncommon. Since slag contains all the elements necessary to form rocks when in contact with seawater and air, slag deposits all over the world could be rapidly influencing their local environments. With this in mind, the team suggested that future researchers update geological models to account for human contributions to the natural rock cycle. 

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In an extraordinary breakthrough that delves deep into the cosmic past, an international consortium of scientists from Dresden, Sydney, and Canberra has uncovered rare signatures of radioactive isotopes embedded within a deep-sea manganese crust. This discovery provides unprecedented insights into the astrophysical phenomena responsible for forging the universe’s heaviest elements, particularly illuminating the timeline of the last significant r-process nucleosynthesis event in the solar system’s vicinity. Their findings, published in the esteemed journal Nature Astronomy, draw a cosmic map that stretches back over 100 million years, signaling the rarity and tremendous scale of cataclysmic events such as neutron star mergers or exceptionally energetic supernovae.

Ferromanganese crusts, mineral deposits found at profound ocean depths ranging from hundreds to thousands of meters, serve as unparalleled geological time capsules. These crusts accrete slowly—millimeters over millions of years—absorbing trace elements, including rare radioactive isotopes transported from distant cosmic events. By decoding these isotopic deposits, researchers can trace the history of cosmic explosions and paint a detailed portrait of stellar processes that shaped the chemical evolution of our galaxy.

Central to this research is the isotope plutonium-244, with its rare genesis through the rapid neutron-capture process, known simply as the r-process. During such events, atomic nuclei experience a rapid succession of neutron captures, instigating the synthesis of heavy elements beyond iron. Conditions conducive to this process are believed to arise predominantly during titanic neutron star collisions or hyper-energetic supernovae, events many orders of magnitude less frequent than typical supernova explosions. Detecting plutonium-244 within the Earth’s geological record offers direct evidence of these rare phenomena.

The team’s meticulous analyses utilized state-of-the-art detection methods to isolate and quantify iron-60, plutonium-244, and curium-247 isotopes in Pacific Ocean crust samples. Iron-60 serves as a definitive marker of conventional supernovae, and its isotope profile corresponded precisely to two well-documented near-Earth supernova events occurring within the past few million years. In stark contrast, plutonium-244 exhibited a distribution pattern dramatically different—one consistent with deposition over a much longer timespan, pointing to a rare cosmic event that transpired at least a hundred million years ago.

Intriguingly, plutonium-244’s widespread but time-extended presence suggests it did not originate from the same near-Earth supernovae that deposited iron-60. Instead, it implies an older, more distant event where the synthesized elements had ample time to diffuse through the interstellar medium, creating a diffuse veil of heavy atoms engulfing the solar neighborhood. This insight recalibrates our understanding of when and how the most massive elements were introduced into our galactic environment.

Adding further weight to this narrative is the absence of curium-247, another isotope forged by the r-process. Despite its pivotal role—curium-247 decays more rapidly than plutonium-244, with a half-life of approximately 15.6 million years—its conspicuous scarcity in the crust sample indicates no recent r-process activity within the last 100 million years. This “expiry date” phenomenon serves as a cosmic clock, reinforcing the conclusion that the solar system’s immediate neighborhood has been devoid of major r-process events for many millions of years.

The technical sophistication required for these measurements cannot be overstated. Detecting individual plutonium atoms amidst an ocean of roughly ten sextillion non-plutonium atoms illustrates the extraordinary sensitivity needed. Recent advancements at the VEGA facility in Sydney, led by Michael Hotchkis, have pushed the boundaries of accelerator mass spectrometry, enabling researchers to detect and map plutonium distribution layer by layer with unparalleled time resolution. This breakthrough is complemented by the pioneering use of the Heavy Ion Accelerator Facility in Canberra for iron-60 detection, underscoring the collaborative, multinational nature of this endeavor.

Furthermore, a comprehensive age model was constructed using beryllium-10 isotopes measured at the DREAMS facility in Dresden. These measurements were instrumental in refining the growth history of the ferromanganese crust, allowing the researchers to place each isotopic signature accurately within a cosmic timeline spanning more than ten million years. Coupled with advanced imaging techniques such as X-ray scanning and 3D reconstruction of smaller drill cores, the team assembled a remarkably precise chronicle of element deposition.

The implications of this research extend beyond the confines of our solar system. Prof. Anton Wallner, head of the Accelerator Mass Spectrometry and Isotope Research Department at HZDR, emphasized that the detected plutonium likely originated from extraordinarily rare cosmic explosions, such as neutron star mergers recently observed via gravitational waves—albeit occurring far outside our own galaxy. These discoveries not only challenge preexisting assumptions about local r-process events but also rule out alternative hypotheses, including the crossing of the solar system through dense interstellar clouds, as a source of these heavy elements.

This research heralds a new era in studying cosmic nucleosynthesis. Upcoming analyses involving lunar samples provided by NASA promise to enrich our understanding of recent r-process events further. Equally exciting is the anticipated operational commencement of the HAMSTER facility at HZDR, which aspires to replicate and surpass current detection capabilities. This facility aims to detect a broader spectrum of rare radionuclides, potentially unlocking fresh insights into the astrophysical origins of our universe’s elemental diversity.

In sum, the discovery of plutonium-244 traces scattered throughout ancient oceanic crust reframes our knowledge of cosmic history and nucleosynthesis. It reveals a universe punctuated by rare, monumental events that have imprinted an indelible trace on Earth’s geological archives. These findings not only illuminate the elemental assembly of the cosmos but also open up new frontiers for studying the universe’s most violent and transformative phenomena with unprecedented detail and temporal precision.

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Subject of Research: Not applicable

Article Title: The timing of the last r-process event near Earth from interstellar 60Fe, 244Pu and 247Cm deposition on Earth

News Publication Date: 15-Jun-2026

Web References: http://dx.doi.org/10.1038/s41550-026-02841-6

References: Published in Nature Astronomy

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Keywords

r-process nucleosynthesis, plutonium-244, curium-247, iron-60, deep-sea manganese crust, neutron star mergers, supernova, radioactive isotopes, accelerator mass spectrometry, interstellar medium, cosmic explosions, element formation

In the profound depths of rocky planets like Earth and Mars, the precise chemical states of mantle minerals play a foundational role in shaping planetary evolution. Among these chemical states, the oxidation state of iron profoundly influences mantle melting behaviors, volcanic gas compositions, and ultimately, the nature of a planet’s surface environment. While the elemental presence of iron in the mantle is well-known, the subtle balance between its ferrous (Fe²⁺) and ferric (Fe³⁺) forms remains a challenging frontier to unravel, particularly under the extreme pressures and temperatures encountered in planetary interiors.

The early stages of planetary formation are marked by the existence of a vast magma ocean—a molten silicate layer blanketing the young Earth and Mars. During this epoch, the oxidation state at which iron integrates into forming minerals dictates subsequent mantle properties and evolution. Accurately determining the Fe³⁺ content in minerals crystallized within this magma ocean stands as a critical step toward understanding the oxidation dynamics that influenced core-mantle differentiation and surface volatile release in nascent planets.

A mineral of prime relevance in this context is majorite, a high-pressure silicate phase stable at depths ranging roughly from 500 to 600 kilometers within Earth’s mantle and near the base of the Martian mantle. Its stability under simultaneously high-pressure and high-temperature conditions makes majorite a significant reservoir for iron deep within these planetary interiors. Therefore, quantifying the Fe³⁺ concentration hosted within majorite under early magma ocean conditions bears directly on models of mantle redox evolution and volatile mobility.

Researchers at Ehime University’s Geodynamics Research Center have pioneered the synthesis of Fe³⁺-rich majorite coexisting with molten silicate magma at pressures around 18 gigapascals and temperatures between 2150 and 2200 degrees Celsius. Utilizing a multi-anvil apparatus capable of reproducing these extreme conditions, the team closely simulated the environment of the early magma ocean. High-precision X-ray Absorption Near Edge Structure (XANES) spectroscopy was then employed at the renowned SPring-8 synchrotron facility to accurately assess the valence state of iron within the synthesized majorite crystals.

The findings reveal an unexpectedly high Fe³⁺ content in majorite crystallized from the magma ocean, second only to bridgmanite, Earth’s most abundant lower mantle mineral. This marked enrichment in ferric iron suggests that early mantle minerals could accommodate significant oxidation capacity, challenging earlier assumptions that high-pressure silicates predominantly contain iron in the ferrous state. The implication is that the early mantle harbored more oxidized iron species than previously anticipated, impacting mantle viscosity, melting relations, and the capacity to store volatile elements.

Importantly, as mantle solids ascend toward shallower depths, phase transitions or mineral decompositions can liberate excess Fe³⁺ that no longer fits within the crystal structures. This released ferric iron potentially contributes to the generation of oxidized magmas, influencing volcanic gas emissions and surface oxidation states. Such a mechanism presents a plausible link between deep mantle oxidation states and the chemical makeup of magmas erupted at the surface, offering fresh insights into the geological histories of both Earth and Mars.

The study’s revelations offer a new lens through which to interpret the evolution of mantle oxidation state gradients over geological time. Understanding how iron’s valence shifts across depth-dependent mineralogical boundaries and during mantle convection cycles will refine planetary differentiation models and volatile cycling frameworks. The presence of Fe³⁺-rich majorite highlights a previously underappreciated redox reservoir deep within planetary interiors.

These results not only enhance our appreciation of Earth’s early differentiated mantle but also extend to Mars, where recent seismic and geochemical data point to a similarly complex mantle composition. The redox state plays an outsize role in Martian volcanic outgassing and atmospheric evolution, making this research vital for reconstructing Mars’ geochemical past and assessing its potential habitability.

From a methodological standpoint, the study exemplifies the power of integrating high-pressure experimental petrology with cutting-edge synchrotron techniques. The ability to recreate extreme planetary interior conditions and directly probe valence states in situ offers a transformative approach to addressing longstanding questions about deep Earth and planetary chemistry.

Furthermore, the recognition that Fe³⁺ can be abundant in magma ocean-derived minerals necessitates revisiting thermodynamic and geochemical models of mantle melting and evolution. Oxidation state strongly influences melting temperatures and mantle rheology, thereby controlling convection patterns and surface tectonics. Such feedbacks are essential to comprehend in the broader context of planetary habitability and evolution.

Ultimately, these insights pave the way for multidisciplinary endeavors bridging mineral physics, planetary science, and geochemistry. They underscore the dynamic interplay between deep Earth processes and surface conditions, revealing how the smallest changes in iron’s electron configuration resonate across planetary systems.

This breakthrough in understanding iron’s complex behavior under extreme conditions promises to guide future explorations of terrestrial and extraterrestrial geology. It sets new constraints on the interior states of rocky planets and sharpens our vision of how early planetary environments were sculpted by subtle shifts deep within.

Subject of Research: High-pressure mineralogy and mantle oxidation states in terrestrial and Martian planets.

Article Title: (Not explicitly provided in the original content.)

News Publication Date: (Not indicated in the original content.)

Web References: http://dx.doi.org/10.1029/2025JB033231

References: Journal of Geophysical Research Solid Earth

Image Credits: Hideharu Kuwahara

Keywords:
– Fe³⁺ in mantle minerals
– Majorite synthesis under high pressure
– Magma ocean oxidation states
– Mantle redox evolution
– XANES spectroscopy at SPring-8
– High-pressure experimental petrology
– Earth and Mars mantle comparison
– Ferric iron incorporation in majorite
– Oxidized magma generation
– Planetary interior chemistry
– Lower mantle mineralogy
– Planetary differentiation processes

New claims challenge inconsistencies in one of the foundational principles of physics.

New research from a team of scientists led by Cornell is transforming how researchers understand one of the

Krotite is a cosmic relic, one of the oldest minerals in the Solar System.

A look at the quest to mine the bottom of the ocean for valuable minerals, the connection between light pollution and allergies and more climate news.

© The New York Times

Most people think of Mars as a big red dustball, but researchers recently found Martian mineral deposits suggesting it was once warm and humid. The team used the Compact Reconnaissance Imaging Spectrometer aboard NASA’s Mars Reconnaissance Orbiter to analyze specific wavelengths of visible and near-infrared light from minerals on Mars’s surface to determine their chemical composition from afar.

Past researchers identified layered silicate minerals, called clays, across the Martian surface. Clays form when water interacts with rock, and record the amounts and chemical compositions of the waters that formed them. As water interacted with Martian surface rocks, it picked up more mobile elements like magnesium and iron and carried them to lower depths in the Martian soils, while less mobile elements like aluminum stayed in place. This process, called leaching, created 2 distinct layers of clays in the Martian rocks. 

Scientists have proposed 2 main hypotheses for how these layered clays formed on Mars. The first is that they formed through underwater leaching in pools or lakes sometime in Mars’ past. The second is that they formed across the Martian surface, where a widespread humid environment provided the moisture needed to leach them. 

To evaluate these hypotheses, a team led by researchers at Purdue University recently estimated the “true” thicknesses of Martian clay layers with a method scientists had previously only used on Earth. Rock layers containing clays can become tilted, making them appear thicker or thinner than they actually are. To address this discrepancy, the team used the High Resolution Imaging Science Experiment (HiRISE) tool on the Mars Reconnaissance Orbiter to create high-resolution elevation maps of the Martian surface. Then they combined these maps with surface composition data from the Compact Reconnaissance Imaging Spectrometer to create 3D composition maps. 

Using the 3D composition maps, the researchers found where each clay layer was exposed at the surface and traced it underground to estimate an angle of tilt. They then used trigonometry to calculate the true thicknesses of each clay layer. They analysed 46 regions across the Martian surface, and found that the combined thickness of both clay layers was around 20 to 680 feet (6 to 200 meters), with an average of about 190 feet (60 meters). That’s a maximum thickness as high as a 60-story building! 

Next, the researchers tested the extent of the clay deposits in a large ancient Martian valley known as the Mawrth Vallis Region. They focused on this region because it had large elevation changes, and scientists in the past had already collected high-resolution chemical composition and elevation data there. 

They explained that if the clay layers were restricted to the lowest parts of the valley where water once existed, and had changing thicknesses and boundaries between layers, this would provide strong evidence in favor of the “underwater leaching” hypothesis. In contrast, if the clay layers were more widespread, with consistent layer boundaries and thicknesses, this would provide strong evidence of a humid surface environment, in favor of the “surface leaching” hypothesis. 

The researchers found that the clay layers extended beyond the lowest parts of the valley and had consistent layer boundaries across more than half a mile (about a kilometer) of elevation change. Thus, they concluded that the clay layers formed by surface leaching in a humid environment. 

These findings conflict with climate models of early Mars, which generally suggest that the Martian surface rarely got above freezing temperatures. To address this discrepancy, the team proposed that these deposits could have formed over a long period of time rather than in a consistently warm and wet environment. If the surface was frozen most of the time, but got above freezing in short bursts, these clay deposits could still have formed, just over a much longer time period. In this case, the Mars climate models and the researchers’ findings would agree.

The researchers acknowledged that their study has some limitations, particularly regarding the sparse sample locations. Though they found strong evidence for a widespread humid environment on early Mars, more in-depth studies of locations like Mawrth Vallis could better constrain the specific surface environmental conditions under which these clays formed and potentially reconcile their data with Martian climate models.

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