Rock weathering tells a new story: more erosion does not always mean more carbon consumption

A study of the Lancang River shows that silicate, carbonate, and sulfide weathering respond differently to erosion

Science China Press

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All data are corrected for runoff using θsil = 0 and θsulf,carb = −0.75. Green indicates carbonate, yellow indicates silicate, and blue indicates sulfide. The dashed lines represent power-law fits to erosion sensitivity. Sites with strong secondary carbonate precipitation were excluded from the fitting. Data from other study areas are reported in Bufe et al. (2024).

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Credit: ©Science China Press

The uplift-weathering hypothesis suggests that tectonic uplift increases erosion, exposes fresh silicate minerals, and accelerates reactions that consume atmospheric CO2. This process has often been invoked as a driver of long-term cooling. However, erosion can also expose sulfide minerals. When sulfides oxidize, they produce sulfuric acid. This acid can dissolve carbonate minerals and release CO2 over geological time scales. The net carbon effect of weathering therefore depends on the balance among silicate weathering, carbonate weathering, and sulfide oxidation. However, the responses of different rock weathering processes to changes in erosion rate remain poorly understood.

To address this scientific issue, Dr. Jinke Liu and Prof. Guilin Han from China University of Geosciences (Beijing) conducted a detailed study of the Lancang River basin on the southeastern margin of the Tibetan Plateau. The team integrated river water chemistry, suspended geochemistry, stable isotope data, channel steepness indices, and erosion rate records. They further applied a convex optimization-based inverse mixing model to quantify the contributions of different sources to dissolved solutes in the river.

The results show that dissolved solutes in the Lancang River mainly come from carbonate and evaporite weathering, while sulfate is mainly derived from sulfide oxidation. After the influence of runoff was removed, different weathering processes showed contrasting responses to erosion. As erosion increased, silicate weathering rates decreased, whereas carbonate weathering and sulfide oxidation rates increased.

The study also found evidence for secondary calcite precipitation in river water, based on calcium isotopes in suspended sediment and river water. Changes in the chemical composition of suspended sediment suggest that silicate minerals may continue to dissolve during downstream transport. Lithium isotopes, hydrogen and oxygen isotopes, and water chemistry further indicate that non-geothermal groundwater contributes substantial amounts of dissolved solutes to the river. Together, these processes can modify the link between erosion rate and chemical weathering at the basin scale. They may also help explain why weathering rates respond differently to erosion in different river basins.

On geological time scales, CO2 released by sulfide oxidation coupled to carbonate weathering in the Lancang River basin exceeds the CO2 consumed by silicate weathering. Downstream in the lower Mekong River plain, where erosion rates are lower and lithology changes, the carbon effect of weathering shifts from a CO2 source to a CO2 sink. Comparison of the Lancang River basin with small silicate-dominated catchments in orogenic belts shows that the Lancang River basin has a moderate erosion rate but still acts as a carbon source. The study suggests that this phenomenon is closely related to differences in basin lithology, thereby complementing and deepening previous understanding of the relationship between erosion rate and carbon effects.

The findings provide new geochemical evidence that lithology, suspended sediment weathering, and groundwater input are important controls on chemical weathering and its carbon effect in large river basins. They also refine how scientists evaluate the relationship among tectonic erosion, chemical weathering, and climate change.

Scaling between Ca/Na in suspended load and calcite saturation index (A), riverine Ca and carbonate cation concentrations (B), and Ca lost to precipitation (C). The concentration of Ca lost to precipitation is calculated from the fraction of Ca remaining in the water (β) and riverine Ca concentration.

The circles represent the Lancang River, while diamonds represent small mountain streams. The colored symbols are calculated with runoff correction θsil =0 and θsulf,carb = −0.75 while the gray symbols are calculated without runoff correction. For most data points, the application of runoff correction does not change the qualitative determination of net CO2 source or sink status. The data for the whole Mekong River basin and other mountain rivers are reported in Bufe et al. (2024) and Relph et al. (2021).

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©Science China Press

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Journal

Science China Earth Sciences

DOI

10.1007/s11430-026-2009-5

Method of Research

Observational study

 

No battery needed: Robot skin harvests power as it walks

Science China Press

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Engineered electrochemical polymer skin membrane enables continuous operation and intelligence in microrobots.

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Credit: ©Science China Press

Powering microrobots has long been a chemical engineering problem. A 1.7 g microrobot can crawl for only about two minutes on commercial batteries. To run for two hours, it would need a battery weighing 94% of its total mass, with an energy density of 5382 Wh kg−1, far beyond today’s lithium-ion technology. Below 1 cm3 or 1 g, microbatteries lose energy density even faster because packaging and conductive materials take up a growing share of their mass.

From carrying batteries to walking on energy

A team led by Yue Gao at Fudan University’s Department of Macromolecular Science tried a different route. Instead of making batteries smaller and denser, the researchers asked whether the robot could harvest energy from the surface it walks on. Active materials such as aluminum, zinc, silicon, tin, and lead are common in pipes, buildings, data centers, and equipment. If a robot’s foot could trigger a chemical reaction on contact, its runtime would no longer be limited by onboard storage.

The team’s answer is an open electrochemical power system: a crosslinked potassium polyacrylate membrane attached to the microrobot’s foot. It converts chemical energy from the substrate and from atmospheric moisture and oxygen into electricity.

A skin that powers, grips, and senses

The membrane is made in one step by polymerizing acrylic acid monomer, crosslinker, initiator, and potassium hydroxide directly on the robot’s foot. A flexible platinum/carbon film acts as the reaction site for oxygen and water. The skin can be as thin as 135 micrometers and as small as 1 square millimeter. On zinc, it delivers a power density of 133 mW cm−2; on aluminum, 103 mW cm−2. These values are about an order of magnitude higher than those of typical microbatteries. The system also retains its current capability when scaled down to 0.0004 cm3. The design must satisfy several conflicting needs at once. It has to hold water, stay flexible, stick to surfaces, release easily, and sense the ground.

Holding water and surviving extreme temperatures

The membrane’s carboxylate groups, potassium ions, and hydroxide ions interact strongly with water molecules. Even at 20% relative humidity, similar to the Sahara Desert, it retains most of its water and continues to discharge after 48 hours. At −20°C, potassium ions disrupt the ordered hydrogen-bond network of water, keeping the membrane ionically conductive. The voltage drops by only about 0.2 V compared with room temperature. The crosslinked structure also allows operation at 80°C. After water evaporates, adding water restores performance.

Power on contact, off on lift-off

The membrane generates electricity when it touches an active substrate and stops when the foot lifts. The substrate loses electrons. On the platinum/carbon side, oxygen and water accept electrons to produce hydroxide ions. The reaction starts in about 0.1 milliseconds and stops when contact ends. Each walking step refreshes the reaction interface. Discharge products remain on the substrate rather than accumulating on the membrane, avoiding the performance decay seen in static batteries.

Sticky in the right direction

The membrane combines strong shear adhesion with easy normal detachment. Carboxylate groups create electrostatic adhesion to metal substrates. In the walking direction, adhesion is strong enough to prevent slipping. In the vertical direction, detachment resistance is low, so the robot can lift its foot efficiently. This allows the microrobot to crawl on inclined aluminum surfaces.

Sensing the ground through ions

The membrane can also sense the surface beneath it. Different materials cause different electrochemical reaction rates and hydroxide consumption, leading to directed migration of potassium ions and a characteristic potential signal. Rough surfaces deform the membrane and change ion distribution, producing another signal. Material changes generate stable square-wave signals, while roughness changes produce millivolt-level spikes. The two signals can be naturally decoupled. With an X-Y electrode array, the membrane can also locate where contact occurs. This helps the robot recognize its environment and actively seek energy-rich paths.

Electrochemical performance of the skin membrane.

Credit

©Science China Press

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Journal

National Science Review

DOI

10.1093/nsr/nwag529

Method of Research

Experimental study

 Burden of pancreatic cancer in China and the United States, 1990–2023

Pancreatic cancer burden rises in both China and the US, but patterns diverge

High fasting glucose overtakes tobacco as leading US risk factor, while China faces dual metabolic–tobacco burden

Chinese Medical Journals Publishing House Co., Ltd.

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(A) 1990; (B) 2023; the connecting lines illustrate changes in the ranking of each risk factor between China and the United States; PAF indicates the proportion of disease burden (DALYs) that could be reduced if a specific risk factor were eliminated at the population level. 95% UI: 95% uncertainty intervals; DALYs: disability-adjusted life years; PAFs: population attributable fractions; PC: pancreatic cancer.

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Credit: Source link: https://www.ovid.com/jnls/jpancreatology/fulltext/10.1097/jp9.0000000000000271~burden-of-pancreatic-cancer-in-china-and-the-united-states

Pancreatic cancer remains one of the deadliest malignancies worldwide, carrying a five-year survival rate of roughly 10% and a heavy toll in disability-adjusted life years. Understanding how its burden and risk factors are shifting across countries is essential for prevention and health planning. 

A new study published in the Journal of Pancreatology on August 7, 2026, compared pancreatic cancer burden in China and the United States from 1990 to 2023 using data from the Global Burden of Disease Study. Researchers analyzed incidence, prevalence, mortality, and disability-adjusted life years (DALYs), alongside socioeconomic inequalities and attributable risk factors. 

In 2023, China recorded more absolute cases than the United States (103,000 vs. 66,000), yet its age-standardized rates were lower: prevalence was 4.51 versus 11.19, and mortality was 4.97 versus 9.56 per 100,000 people. From 1990 to 2023, the absolute burden of pancreatic cancer grew in both countries, though age-standardized DALYs declined slightly in China (-0.15%) while increasing in the United States (0.12%). The burden peaked at ages 60–74 in China and shifted to older ages (70–84) in the United States. 

A striking finding was the shift in risk factors. High fasting plasma glucose surpassed tobacco use as the leading attributable risk factor in the United States; in China, it has become a major contributor, comparable to tobacco use—highlighting the growing importance of metabolic risk management in pancreatic cancer prevention. The global burden also remained concentrated in regions with a high socio-demographic index, while absolute socioeconomic inequality increased over time. 

The authors conclude that tailored, country-specific prevention strategies—particularly those addressing rising metabolic risk factors—will be essential to curb the growing burden of pancreatic cancer in the coming decades. 

 

*** 

 

Reference 
DOI: 10.1097/JP9.0000000000000271 

 

About Dr. Yifei Hu from Capital Medical University, China 
Yifei Hu, Department of Child, Adolescent Health and Maternal Care, School of Public Health, Capital Medical University, Beijing 100069, China. E-Mail: huyifei@ccmu.edu.cn 

 

About Dr. Wenming Wu from Peking Union Medical College Hospital, China 
Wenming Wu, Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China. E-Mail: doctorwuu@126.com  

 

Funding information 
This research was funded by the Beijing Natural Science Foundation (No. L258025) and the National Natural Science Foundation of China (No. 72061137007). 

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Journal

Journal of Pancreatology

DOI

10.1097/JP9.0000000000000271

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Burden of pancreatic cancer in China and the United States, 1990–2023

How sea squirts perceive underwater noise

Marine Biology

Ruhr-University Bochum

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Sound pressure alone does not suffice

“We examined the sea squirt Halocynthia papillosa to see which components of low-frequency, vibroacoustic stimuli elicit behavioral responses,” reports Til Böttner for his doctoral thesis. “In field experiments in the Mediterranean and under controlled lab conditions, the creatures responded with contractions mainly to stimuli between 50 and 800 Hertz. Interestingly, these reactions were associated with increased vibrations in the substrate.”

Surprisingly, the sea squirts showed no comparable reactions even at underwatersound pressure levels exceeding 130 decibels, provided that substrate vibrations remained below the determined reaction thresholds. “The results show that sound pressure alone cannot explain the observed behavioral reactions,” Huhn concludes.

A close look at the nervous system

It is not yet certain which sensory structures perceive the mechanical stimuli. However, sea squirts possess specialized ciliated mechanoreceptor cells in the region of the siphons, particularly in what is known as the coronal organ. These may register local movements in the water or mechanical deformations. “Further physiological and neurobiological studies are required to determine whether these receptors are stimulated by particle motion in the water in the water or by vibrations transmitted via the substrate and the mantle,” says Böttner.

Questions remain

Sound pressure, particle motion, and substrate-borne vibrations are physically closely intertwined under water, especially at low frequencies. This makes it impossible to completely separate these factors, including in the current study. “However, the findings show that mechanical components of underwater sound have to be more closely considered in the examination of benthic organisms,” say the researchers in Bochum.

Future studies aim to identify which mechanical stimuli are actually perceived and how these are sensorially and neuronally processed. To achieve this, the research conducted at the Department of General Zoology and Neurobiology at Ruhr University Bochum combines marine biology, bioacoustics, and neurobiology to understand the effects of anthropogenic underwater noise in greater detail. The work has drawn international recognition: Til Böttner received the prize for the best presentation by an early-career researcher for his presentation of his research at the International Tunicate Meeting (ITM).

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Journal

Marine Biology

DOI

10.1007/s00227-026-04943-1

Method of Research

Observational study

Subject of Research

Animals

Article Title

Feeling the noise: Behavioural Responses in Ascidians Are Associated With Substrate-Borne Vibrations Rather Than Sound Pressure Alone

 

Even high-altitude forests in Switzerland are now weakened by frequent droughts, making natural hazards more dangerous

Essential ‘protective’ forests in highest tree belts were until recently shielded from climate change, but no longer

Frontiers

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Due to global warming, Swiss forests are now at a tipping point where the tolerance and resilience of trees against summer droughts are being overwhelmed, scientists have shown. That bodes ill for people in the valleys, because forests form their first line of defense against avalanches, rockfalls, landslides, and floods.                                                                                       

“Here we show that it no longer holds true, as was until recently the case, that trees growing at the highest altitudes are mostly shielded from the worst effect of summer droughts,” said Dr Estelle Noyer, a researcher at Bern University of Applied Sciences and the first author of a new study in Frontiers in Forests and Global Change.

“Even as high as at 2,200 meters altitude, the number of trees per stand is reduced due to the decline or death of large, dominant trees in particular. This causes a progressive decline of these precious forests which protect against natural hazards.”

On a slope to drought

Even before climate change was making itself felt, forests were vulnerable to drought every summer. Historically, forests at low altitude vegetation belts like the ‘colline’ (between 282 and 1,184 meters above sea level) and ‘montane’ (600 to 1,648 meters) belts were the most prone, as cold temperatures and a long-lasting snowpack kept soils moist and limited trees’ demand for water in the highest, the ‘subalpine’ belt between 1,235 and 2,219 meters.

Subalpine trees can also suffer from drought, but it was previously thought that higher temperatures due to global warming are giving these a net growth boost, making them recover faster. But over recent decades, rapid warming at intermediate and high altitudes has made trees ‘thirstier’. At the same time, a drop in precipitation and the retreat of glaciers have cut the water supply to soils, making droughts more frequent.

Noyer and colleagues wanted to know if the altitudes at which drought stress commonly strikes in the Swiss protective forests have shifted over the past four decades, and whether this is impacting the resilience of the canopy and the make-up of forest stands. They analyzed records gathered between 1983 and 2022 by the Swiss national forest inventory (NFI), which lists all stands across a nation-wide grid.

Foresters regularly measured the diameter at breast height of all trees across hundreds of representative 200-square-meter plots. Noyer and colleagues here focused on protective forest stands, exclusively in areas that hadn’t been damaged by fires or undergone interventions like selective logging. For each of five time periods within the NFI, they looked at 891 to 1,543 tree stands between 282 and 2,219 meters altitude.

Growing problems

The results showed that the percentage of declining stands increased over time in every belt, but especially at lower altitudes. The strongest decline was seen in the colline belt, where the ‘declining’ share among protective stands increased from 11.1% in 1983 to 30.4% by 2022. In the lower montane belt, this rose from 17.4% to 21.4%, but stayed approximately constant around 10.8% in the higher montane belt. And in the highest belts, the ‘subalpine inferior’ (1,208 to 1,897 meters) and ‘subalpine superior’ (1,752 to 2,219 meters), the percentage of declining stands dipped to its lowest value between 10.3% and 15.3% in the mid-1990s to early 2000s, before rising sharply to 18.8% over the years since then.

The density of trees decreased in all belts over time. As expected, declining stands typically displayed the highest drought indices and the strongest drop in tree basal area, indicating more severe drought stress and a shrinking tree cover. But importantly, the historic strong link between higher altitude and less severe drought stress was no longer visible after 2017.

The authors concluded that the composition of stands in the Swiss protective forests changed over time, as the most vulnerable and largest trees were selectively killed off by droughts, even at the greatest heights. As a result, today’s stands appear to be composed of more resilient tree species and size classes – but which may be weakened when drought episodes occur in quick succession, as is increasingly common.

Noyer et al believe that there is a pressing need for adaptive forestry strategies, not only in Switzerland but throughout European ranges.

“The critical open questions center on how rapidly forest species composition will change, and how foresters can make forests more resilient by promoting multi-layered and diverse stands. Our ongoing follow-up study is expected to yield actionable spatial data to help foresters achieve this,” said Noyer.

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Journal

Frontiers in Forests and Global Change

DOI

10.3389/ffgc.2026.1933304

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Four decades of drought impacts on Swiss protective forests: a vanishing altitudinal gradient

Article Publication Date

1-Oct-2026

New surgical technique restores the clitoris after treatment for vulvar cancer

After the penis, reconstruction of the clitoris has finally become available for women

Radboud University Medical Center

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Plastic surgeon Tim Nijhuis and gynaecologic oncologist Mieke ten Eikelder from Radboudumc performing a reconstruction of the clitoris

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Credit: Radboudumc, Stephan van Raaij

For women who lose part of their clitoris because of vulvar cancer, a clitoral reconstruction procedure has now been developed for the first time. This comes forty years after the first penile reconstruction surgery. Results in the initial group of patients are encouraging.

Surgery for vulvar cancer can save lives, but it can also significantly affect a woman's sexual function and quality of life. ‘When the tumor is located in or around the clitoris, we sometimes have to remove part of it’, explains gynecologic oncologist Mieke ten Eikelder from Radboudumc. ‘Until now, the wound was simply closed afterward, and the clitoris disappeared beneath a layer of skin, with little attention paid to quality of life or whether orgasm would still be possible.’

The first reconstructive surgery for the penis after cancer dates back to 1987. It was therefore high time to develop a method to restore the sexual function of the clitoris as well. Plastic surgeon Tim Nijhuis, together with Ten Eikelder, developed a new surgical technique. Nijhuis: ‘Once the tumor has been removed, the nerve bundles are released and repositioned to create a new clitoral tip. We then cover it with a small graft of buccal mucosa. This tissue type closely resembles the tissue found around the vulva.’ This approach helps preserve clitoral sensation.

Clitoral orgasm

Among the first 23 women with vulvar cancer who underwent the reconstruction procedure, ninety percent were able to achieve a clitoral orgasm again after surgery. This typically occurred between three and six months after the operation. Ten Eikelder: ‘Initially, the clitoris may be overly sensitive or, conversely, less sensitive. However, recovery is generally optimal after one year. In most women, sensation returns to a level comparable to what it was before surgery.’

Approximately 450 women in the Netherlands are diagnosed with vulvar cancer each year. In about one-quarter of these cases, the clitoris or surrounding area is involved. The reconstruction adds only about fifteen minutes to the operation. In addition to vulvar cancer treatment, this reconstructive technique may also help women who have suffered genital mutilation.

Training other centers

The clitoral reconstruction procedure is now being introduced nationwide as part of a scientific research program. Alongside Radboudumc, eight other Dutch hospitals treat vulvar cancer. All of them are participating in a follow-up project in which gynecologic oncologists and plastic surgeons will be trained in the new technique. In addition, Nijhuis and Ten Eikelder are currently training specialists from other countries.

While the initial results are encouraging, the researchers emphasize that further study is needed. With financial support from the Dutch Cancer Society, they will work together with other Dutch hospitals to determine whether the reconstruction truly improves sexual function and quality of life, and how the technique can be safely integrated into everyday clinical care.

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Journal

Gynecologic Oncology

DOI

10.1016/j.ygyno.2026.07.013

Method of Research

Experimental study

Subject of Research

People

Article Title

Clitoral reconstructive surgery for patients with vulvar carcinoma