It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Saturday, September 05, 2026
Less UV light may mean less carbon storage in Antarctic tundra
Institute of Atmospheric Physics, Chinese Academy of Sciences
The Antarctic ozone layer is recovering, a major environmental success following the Montreal Protocol. As the ozone layer heals, less ultraviolet radiation reaches the Antarctic surface—a change usually viewed as beneficial for living organisms.
But a new field study suggests that the ecological story may be more complicated. Researchers from the Institute of Atmospheric Physics, Chinese Academy of Sciences, China together with collaborators from the University of Science and Technology of China and other institutions, found that reduced ultraviolet radiation can substantially weaken the ability of Antarctic tundra to absorb carbon dioxide. These results were recently published in Atmospheric and Oceanic Science Letters.
The team carried out in situ field experiments on Ardley Island in West Antarctica, where mosses and lichens form fragile tundra communities. Using transparent filters, the researchers simulated two levels of ultraviolet reduction—about 20% and 50%—while measuring carbon dioxide exchange, photosynthesis, and ecosystem respiration.
The results were striking. A 20% reduction in ultraviolet radiation weakened the tundra carbon sink by about half. A 50% reduction weakened it by about 80%, and in some observation periods the tundra even showed signs of shifting from a carbon sink to a carbon source.
"We might expect lower ultraviolet radiation to be simply beneficial, but Antarctic tundra does not respond in such a straightforward way," says Prof. Xiyan Xu, a corresponding author of the study. "In this sensitive ecosystem, changes in ultraviolet radiation can affect plant photosynthesis, microbial decomposition, and the overall carbon balance at the same time."
The study also found that different tundra environments respond through different pathways. In western lowland tundra, where penguin and other marine animal activity is limited, the weakened carbon sink was mainly linked to reduced photosynthesis. Antarctic mosses and lichens have adapted to high-ultraviolet environments, and lower ultraviolet exposure may alter their protective pigments, light-use processes, and carbon fixation capacity.
In eastern lowland tundra, where penguin activity is strong, the main driver was increased ecosystem respiration. Penguin colonies add large amounts of organic carbon and nitrogen to the soil, creating nutrient-rich conditions for microbes. When ultraviolet stress is reduced, microbial activity may increase, accelerating decomposition and releasing more carbon dioxide.
"Penguin-derived nutrients make these tundra soils biologically active," says Dr. Tao Bao, the first author of the study. "Under lower ultraviolet radiation, this nutrient-rich environment may amplify respiratory carbon loss from the ecosystem."
The findings suggest that ozone-layer recovery should not be viewed only through the lens of reduced ultraviolet damage. For Antarctic tundra communities that have long adapted to strong ultraviolet exposure, declining ultraviolet radiation may reshape plant–microbe interactions and carbon cycling. The researchers plan to combine longer-term field observations with ecosystem modeling to better understand how ultraviolet change, penguin activity, and climate warming together influence the future carbon balance of Antarctic tundra.
Ozone layer recovery weakens the Antarctic tundra carbon sink
Cathode material recycling: a review of current methods and a proposal for the future
The massive amount of lithium ion batteries (LIBs) globally can lead to major environmental, economic and sustainability concerns. This review establishes the existing methods of recycling and suggests a closed-loop design to diagnose and recycle the LIBs
Schematic overview of degradation mechanisms of spent Li‑ion battery cathode materials and three representative recycling routes: no‑destruction treatment, direct recycling/upcycling, and element extraction.
Lithium ion batteries (LIBs) are inescapable in everyday life. From electric vehicles to portable devices, LIBs are in high demand. With more knowledge of the effect unrecycled battery components have on the environment and the economy, researchers from the Beijing Institute of Technology have compiled a review of the current recycling approaches for spent cathode materials as well as proposing a closed-loop recycling system powered by artificial intelligence. This process uses AI to match the specific failure state of the cathode materials to the most effective strategy for recycling. By developing this approach, Lai Chen and his team hope to relieve the load on the environment and the supply chain by reusing materials that still have life in them, along with altering the paradigm we operate under to shift from “traditional, rough processing” to “precise recycling”.
Future estimates on waste produced by LIBs for electric vehicles alone are projected to be up to 8 million tons by 2040: a staggering number for only one area of LIB use. Not only is this waste detrimental to the environment, but many of the metal resources within the cathode material of the battery might still have use available for other applications. Recycling will decrease the pressure on the supply chain for metals like lithium, manganese, cobalt and nickel.
There are recycling methods in use that vary in their effectiveness in reducing greenhouse gas emissions, namely pyrometallurgical (17% reduction), hydrometallurgical (51%), and direct recycling/upcycling (61%). The potential greenhouse gas emission reduction by these methods could be up to 16.3% in 2060 using the Lithium Cycle Computable General Equilibrium (LCCGE) model. However, these methods use rough sorting, which can damage the materials and affect the overall amount recovered.
The use of artificial intelligence can change the way metal cathode material recycling occurs by using precision recycling, a method that would require highly trained AI models and robust sets of data on batteries, their materials, and various capacities and degradation metrics.
“The application of artificial intelligence can enable adaptive, data-informed decision-making throughout the battery life cycle, effectively overcoming the critical barrier caused by the lack of reliable data regarding the state of retired batteries,” said Lai Chen, author of the review and associate professor at Beijing Institute of Technology.
AI use in this field would highlight the optimal recycling route using non-destructive methods based on the failure features of the cathode materials. Such failure features that would be used to determine recycling strategy include lithium loss, surface/interface deterioration, transition-metal dissolution, and structural disorder and phase reconstruction. The digital intelligence technologies and sorting/recycling procedures would be integrated and work together in one facility to promote the closed-loop system proposed.
Chen suggests a call to action for future researchers to systematically document cathode degradation metrics to begin establishing comprehensive datasets for AI models to learn. The information needed would include cathode degradation metrics such as lithium inventory loss ratios, structural phase transition percentages and transition-metal dissolution concentrations.
This type of information is indispensable to developing the closed-loop design and will allow for evaluations of state of charge, state of health and remaining useful life to be determined. Additionally, the standardization of battery health diagnostics, which has yet to be established, is needed to develop this system.
Rui Tang of the School of Materials Science and Engineering at the Beijing Institute of Technology, along with Hong Liu, Lai Chen, Jinyang Dong, Yi Jin, Xianglei Meng, Yiling Ren, Yuchen Wei, Huimin Yang, Yun Lu, Qing Huang and Yuefeng Su also of the Beijing Institute of Technology Chongqing Innovation Center, and Yibiao Guan of the China Electric Power Research Institute contributed to this research.
The National Natural Science Foundation of China, The High-Level Talent Introduction Project of Yibin and the China Postdoctoral Science Foundation supported this study.
Precision Recycling of Spent Cathode Materials: From Degradation Mechanisms to Recycling Strategies
Scientists crack a years-long "mystery signal" hidden in a quantum material
The world's first identification of the "beating" signal's origin, quantum interference between topological and ordinary electronic states, establishes a new criterion for analyzing and designing quantum devices.
Credit: Korea Research Institute of Standards and Science (KRISS)
A team of Korean researchers, including the Korea Research Institute of Standards and Science (KRISS, President Dr. Lee Ho Seong) and the Gwangju Institute of Science and Technology (GIST, President Lim Kichul), has become the first in the world to identify the origin of the “beating*”signal that has long been a major obstacle to interpreting quantum signals in topological insulator (TI) nanowires. Their analysis confirmed that the beating arises when two different quantum oscillations overlap, where one created by the topological electronic states on the surface and the other by the ordinary electronic states inner the nanowire. This achievement provides a key criterion for interpreting the signals of topological quantum devices and for realizing desired electronic states.
* Beating: a phenomenon in which oscillations with slightly different periods overlap, causing the overall oscillation intensity to periodically grow stronger and weaker.
A topological insulator is a quantum material that conducts little electricity in its interior but hosts special electronic states on its surface. When such a material is made into a thin nanowire, the surface electrons travel around its perimeter, and when a magnetic field is applied, the electron waves that have passed through different paths interfere with one another, producing "Aharonov-Bohm (AB) oscillations," in which the conductance changes at regular intervals for varing magnetic fields. In real topological insulators, however, factors such as doping can create a thin layer just beneath the surface where electrons also flow. This layer, too, can serve as a path for electrons, but whether it participates in AB oscillations together with the topological surface states has remained unclear.
The clue to solving this question came from a thermoelectric experiment. While examining whether AB oscillations also appear in the thermoelectric effect of antimony (Sb)-doped bismuth selenide (Bi₂Se₃) nanowires, the researchers discovered "beating." Beating is a phenomenon in which oscillations with slightly different periods overlap and the signal intensity varies, much like two tuning forks producing a pulsing "wah-wah" sound; it was the decisive clue that captured the presence of another, unexpected oscillation component. Based on this, the researchers re-analyzed their earlier electrical conductance data and confirmed that the same beating phenomenon had been present all along.
After years of tracking and analysis, the researchers concluded that the beating arises when oscillation components originating from the “Topological Surface State (TSS*)” and the “Two-Dimensional Electron Gas (2DEG**), an ordinary electron layer beneath the surface, overlap.” They found that the electron paths passing through these two conduction states enclose slightly different cross-sectional areas of the nanowire, generating oscillations with different periods that superpose to produce the beating.
* Topological Surface State (TSS): A special electronic state formed on the outermost surface of a topological insulator.
** Two-Dimensional Electron Gas (2DEG): A common electronic state in which electrons gather and move in a thin layer beneath a material's surface.
The key to verification lay in the oscillation frequency. Because the frequency is determined by the area of the path along which electrons circle the nanowire, the frequency should remain the same even when the electronic state is changed by the gate voltage, as long as the path area stays constant. However, since neighboring oscillations overlapped, they were difficult to distinguish using conventional frequency analysis. To address this, the collaborating team led by Professor Song Taegeun of Kongju National University used machine learning to separate the oscillation components that had appeared clustered together in previous analyses, confirming that each frequency remained distinct even as the beating pattern changed with the gate voltage. Theoretical calculations also reproduced the observed characteristics, and the same phenomenon was verified in a separate nanowire device.
This study clearly demonstrated that ordinary electronic states can also take part in AB quantum interference, which has been used as a key signal for identifying topological surface states. In doing so, it established a clear criterion for accurately interpreting the quantum transport signals of topological insulators without error and for precisely controlling desired quantum states in the future.
Dr. Bae Myung-Ho, Principal Research Scientist in the Quantum Device Group at KRISS, said, “This achievement shows that electrons can undergo quantum interference by moving through not only topological states but also ordinary electronic states.” He added, “To make use of only the desired topological state, it is important to precisely control doping and the gate so that the ordinary conduction state does not intervene.”
Professor Choi Sang-Jun of the Department of Physics and Photon Science at the GIST said, “By bringing together the experimental, theoretical, and data-analysis capabilities of the research teams at each institution, this achievement explains, within a single physical picture, the origin of the beating that had gone unsolved for years.” He added, “The principle of understanding and controlling the interference between different electronic states could also be applied to the design of toological quantum devices in the future.”
The young planet was characterised by a global magma ocean and a liquid metallic core, before cooling and differentiating to acquire its current internal structure.
As the BepiColombo mission prepares to enter the final phase of its journey to Mercury, a series of studies conducted by researchers at the University of Liège and KU Leuven sheds new light on the early stages of the evolution of the planet closest to the Sun. Using experimental petrology, the researchers are reconstructing in the laboratory the formation of Mercury’s core, the crystallisation of its magma ocean and the formation of its mantle.
The terrestrial planets (Mercury, Venus, Earth and Mars) are the result of more than four billion years of evolution, which began with accretion from the disc surrounding the young Sun. During the early stages of evolution, the heat released caused these planets to melt, creating what is known as a magma ocean. This key stage determines the distribution of elements between the metallic core and the mantle. As it crystallises, this ocean structures the solid mantle, the partial melting of which will subsequently generate the magmas that form the crust. It is also at this stage that an initial atmosphere may form.
To date, no samples have been taken from Mercury, and no meteorites have been linked to it. Our knowledge of its composition therefore relies on telescope observations and data from the American probes Mariner 10 (1973) and MESSENGER (2011). However, in order to reconstruct the planet’s history, scientists draw on a specialised discipline: experimental petrology. This branch of geology enables scientists to reproduce, in the laboratory, the temperatures, pressures and chemical conditions that prevailed inside the planet more than four billion years ago, and then to analyse the minerals, metals and gases that make up the planet’s various layers.
It was by employing these techniques that the teams led by Bernard Charlier (ULiège) and Olivier Namur (KULeuven) carried out an extensive series of high-pressure, high-temperature experiments (at temperatures of between approximately 1,250 and 2,170 °C) and at pressures equivalent to those found deep within the planets, in order to simulate and track the behaviour of carbon during the separation of the metallic core from the silicate magma of the mantle.
Carbon that changes sides depending on the conditions...
From the results obtained, the teams were able to deduce that the behaviour of carbon depended heavily on the oxidation state of the environment, as measured by the oxygen fugacity (fO2 ). “Under relatively oxidising conditions, carbon is strongly siderophile,” explains Bernard Charlier, a geologist at ULiège. “In other words, carbon prefers metal and therefore enters the core. But under the highly reducing conditions specific to Mercury, it becomes much less siderophile (attracted to metal), and so remains in the silicate magma, where it eventually crystallises as graphite.”
Based on these experiments, the team reconstructed how carbon was distributed between Mercury’s core, mantle, crust and primitive atmosphere. By comparing these results with the thickness of the graphite crust calculated from data from the MESSENGER probe, they were able to determine the conditions that prevailed during the planet’s formation – undoubtedly an environment extraordinarily low in oxygen.
... and a graphite crust formed by flotation
“Under these extreme conditions, graphite is too light to sink; it floats on the surface of the magma ocean and accumulates to form a primitive crust,” adds Olivier Namur, also a geologist. The model reproduces a graphite crust approximately 40 to 120 metres thick, consistent with the carbon-rich layer (1 to 3 per cent by mass) that observations attribute to Mercury’s surface.” This primordial crust would then have been disrupted and redistributed by meteorite impacts and by the volcanism that built the planet’s more recent crust.
MESSENGER’s geodetic data also indicate that the exceptionally large core (accounting for around 70 per cent of the planet’s mass) must contain several per cent of light elements to account for its density deficit. “Carbon had been proposed as a candidate,” continues Olivier Namur. “However, under the very conditions that allow the graphite crust to form, the study shows that the core remains low in carbon – less than 5,000 micrograms per gramme, or less than 0.5 per cent. Such a concentration is far too low to account for the observed deficit.”
It is therefore primarily silicon and, to a lesser extent, sulphur that must constitute the light elements of the core. These elements have another property: they significantly lower the melting point of iron, which could explain why Mercury’s core has remained at least partially liquid for 4.5 billion years – a characteristic necessary to sustain its magnetic field.
By linking Mercury’s extreme chemical reduction to both its graphite crust and the structure of its core, this research provides a useful framework for understanding other highly reduced bodies: the original, more massive proto-Mercury; the hypothetical ‘super-Mercuries’; certain carbon-rich exoplanets, and also the early Earth, which was largely built from reduced materials. “Future observations, notably by missions such as BepiColombo, could confirm and quantify graphite as a major phase on Mercury’s surface,” concluded Bernard Charlier.
The contour lines show radio emissions from carbon monoxide molecules in Stephan’s Quintet, arranged like the contours on a topographic map. Just as higher contours on a map represent higher elevations, higher contour levels here represent stronger CO emission, indicating regions with more molecular gas.
Star formation in galaxies is closely linked to molecular gas. In the distant past, when galaxy interactions were more common, these encounters compressed molecular gas, causing dense clouds to collapse under their own gravity and form new stars.
However, a curious phenomenon occurs in some regions with abundant molecular gas. Despite having plenty of the raw material needed to make stars, they produce surprisingly few. Why a galactic collision can trigger star formation in some regions while suppressing it in others has long intrigued scientists.
To understand this phenomenon, a research team at Osaka Metropolitan University used the Atacama Compact Array, a network of radio telescopes in Chile, to create the first detailed map of the molecular gas throughout Stephan’s Quintet, a nearby group of interacting galaxies where some regions form stars far less efficiently than expected.
When the researchers compared the amount and motion of gas in different regions with how efficiently each region was forming stars, they found that regions where the molecular gas was moving more violently tended to form stars much less efficiently, even in the presence of abundant gas.
“Interactions between galaxies can both compress and disperse molecular gas, creating dramatic differences in star formation activity,” Misaki Yamamoto of the Graduate School of Science explained. “The findings pointed to turbulence as an important factor in regulating where stars can form.”
They propose a model where the turbulence generated by the galaxies’ interactions prevents the gas from settling and collapsing under its own gravity. If the gas is highly turbulent, its motions spread out the gas, preventing parts of the cloud from settling, becoming concentrated, and collapsing. This creates fewer opportunities to form stars.
“Star formation is one of the most fundamental processes in galaxy evolution. Studies like ours help refine our picture of the universe and encourage us to reflect on our place within it,” Associate Professor Kazuyuki Muraoka said. “Understanding how galaxy collisions and interactions in the early universe enhance or suppress star formation will allow researchers a better tool to trace the history of galaxy evolution across cosmic time.”
The findings were published in The Astrophysical Journal.
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