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)
Wednesday, August 20, 2025
Researchers identify increased microbial carbon use efficiency upon abrupt permafrost thaw
Thawing permafrost is a major climate risk due to the associated release of carbon dioxide and other greenhouse gases (GHGs). However, new research by a team led by Prof. YANG Yuanhe from the Institute of Botany of the Chinese Academy of Sciences shows how microbes can stabilize soil carbon and potentially weaken the climate risk.
In a new study published in PNAS, the researchers provide compelling evidence that microbial carbon use efficiency (CUE)—the proportion of carbon uptake used for microbial growth—rises following abrupt permafrost thaw.
Using a substrate-independent 18O-tracing approach, the researchers examined how microbial CUE changes after abrupt permafrost thaw. They collected topsoil samples representing the permafrost thaw sequence—i.e., the different phases of the thawing process—as well as samples from five additional thaw-affected sites on the Tibetan Plateau.
The results from both the thaw sequence and the regional sites consistently revealed that microbial CUE increased after permafrost thaw, demonstrating the generality of the finding.
Further analysis indicated that this rise in microbial CUE was largely driven by shifts in microbial community composition, including a higher fungal-to-bacterial biomass ratio and a greater prevalence of fast-growing taxa in thawed soils. Increased availability of soil phosphorus upon thawing also provided microbes with essential nutrients, thereby supporting growth and enhancing CUE.
Traditionally, abrupt permafrost thaw has been considered a major source of GHG emissions, accelerating carbon–climate feedback. However, the observed increase in microbial CUE may promote the incorporation of microbial-derived compounds into the soil, fostering the formation of stable soil carbon and potentially mitigating the intensity of carbon–climate feedback.
This study sheds light on how abrupt permafrost thaw affects microbial CUE and highlights the critical role of microbial physiology in determining the fate of permafrost carbon.
Increased microbial carbon use efficiency upon abrupt permafrost thaw
Article Publication Date
12-Aug-2025
Novel catalytic method transforms plastic waste into high-value chemicals
Researchers report a novel process that converts polyethylene and polypropylene into valuable olefins, offering an eco-friendly and cost-effective recycling path
A catalytic strategy using tungsten- and sodium-based catalysts enables low-temperature conversion of polyethylene, polypropylene, and their mixtures into light olefins at 320 °C, recovering up to 95% of their carbon content for reuse in fuels and chemicals.
Credit: UNDP in Europe and Central Asia from Openverse
The widespread use of plastic has resulted in one of the most pressing waste management challenges of the modern era. With cumulative waste reaching an estimated 6,300 million tons, finding solutions that are both environmentally responsible and cost-effective has become an urgent priority. Recycling is often viewed as the ideal solution, but traditional methods have significant drawbacks. Many rely on extreme temperatures or expensive noble-metal catalysts, producing complex mixtures that are difficult to separate. Others break down plastics only partially or are energy intensive which negates the environmental benefits.
To this end, a research group including Dr. Yafei Fan from Shandong University, China and Dr. Fawei Lin from Tianjin University, China, published an article in Research on June 10, 2025, sharing insights on a study by Conk et al. featured in Science, which presents a catalytic approach for converting polyethylene and polypropylene and their mixtures, commonly used in packaging and consumer goods, into reusable chemicals. This catalytic method uses inexpensive, widely available base-metal catalysts, operates under relatively mild conditions, and produces fewer unwanted byproducts.
“The developed method has the potential for efficient conversion of plastic waste without requiring extensive pretreatment or separation processes,” Dr. Fan notes.
The process uses two catalysts: tungsten oxide on silica (WO3/SiO2) and sodium-doped gamma-alumina (Na/ɣ-Al2O3). Working in tandem, they drive a reaction known as catalytic cracking and isomerizing ethenolysis, breaking down long polymer chains into light olefins (compounds made up of hydrogen and carbon, with one or more pairs of carbon atoms linked by a double bond) such as propylene and isobutylene. These olefins are highly valued as feedstocks for fuels and polymers, with a combined global market value exceeding 40 billion US dollars.
Each catalyst plays a distinct role in the process: WO3/SiO2 facilitates metathesis, breaking down long polyolefin chains by cleaving and rearranging their double bonds, while Na/ɣ-Al2O3 promotes isomerization by shifting the positions of those double bonds. Working together, these catalysts enable a highly efficient transformation at just 320 °Celsius (C) under 15 bar of ethylene for 90 minutes—significantly milder conditions compared to the 500 °C or higher temperatures typically required for pyrolysis. In experimental trials, this method converted over 95% of the carbon in plastic into useful products, achieving a propylene yield as high as 87% for polyethylene.
The researchers also identified potential areas for improvement that could make the method more viable for plastic recycling. One major limitation is the declining stability of the catalysts over multiple cycles, particularly due to sintering and carbon deposition. To mitigate these effects, they proposed structural modifications such as doped architectures, core–shell designs, and regeneration strategies to enhance durability. Additionally, integrating this catalytic process with advanced sorting systems, such as AI-powered near-infrared detection, could improve the overall recycling efficiency. They also stressed the need to evaluate the method on mixed plastic waste streams, a significant challenge in recycling.
Despite these challenges, the catalytic strategy proposed by Conk et al. represents a promising step toward scalable and sustainable plastic recycling. This Perspective article highlights how insights from the study by Conk et al. could help design next-generation catalysts that are more robust, selective, and capable of handling a wider variety of plastic materials.
“Base-metal catalysts have shown promise for high-yield conversion. Continued research into advanced catalysts, such as high-activity single-atom catalysts, and optimized upcycling processes could reveal new, highly efficient plastic waste disposal methods,” Dr. Lin concludes.
About Shandong University
Shandong University is a is a key comprehensive university with a long and honorable history, broad variety of disciplines, strong academic strength and distinctive characteristics. Spread across an area of over 533 hectares, the university has campuses in three cities and currently offers 12 general disciplines for undergraduates and postgraduates. The university boasts 12 State-level scientific research platforms, as well as six projects in the national program for introducing talent for discipline innovation in colleges and universities. With an already profound academic foundation and even more untapped potential, SDU is widely tipped to achieve its goal of becoming one of the world's highest-ranking universities.
Website: https://www.en.sdu.edu.cn/
About Tianjin University
Tianjin University, founded in 1895 as Peiyang University, is the oldest modern higher education institution in China. With a history spanning over 130 years, it has played a pioneering role in Chinese education and innovation—from developing the country's first aero engine to establishing its first hydraulics laboratory. Today, Tianjin University is a leading research and teaching institution, home to over 40,000 students, including undergraduates, master's, and doctoral candidates. Its enduring legacy reflects the spirit of resilience and progress, making it a key contributor to China’s scientific and technological advancement.
Website: http://en.tju.edu.cn
About the Journal Research
Launched in 2018, Research is the first journal in the Science Partner Journal (SPJ) program. Research is published by the American Association for the Advancement of Science (AAAS) in association with Science and Technology Review Publishing House. Research publishes fundamental research in the life and physical sciences, as well as important findings or issues in engineering and applied science. The journal publishes original research articles, reviews, perspectives, and editorials and has an impact factor of 10.7 and a CiteScore of 13.3.
Biodiversity credits designed to incentivise the conservation and restoration of natural habitats need better transparency and regulation to be effective and credible.
A new study by scientists from the University of Nottingham’s School of Geography has assessed 11 major biodiversity credit suppliers against six integrity criteria defined by the International Advisory Panel on Biodiversity Credits (IAPB). Results show an average score of 2 out of 3, with notable weaknesses in verifiable outcomes, particularly relating to the independence of third-party validation and verification, and transparency in risk disclosure. The results have been published in Proceedings of the Royal Society B.
Biodiversity credits are generated when measures of positive biodiversity outcomes are verified. When these credits have been properly validated and verified, biodiversity credits represent the evidenced addition (or avoided loss) of biodiversity that resulted from a restored (or conserved) site.
Biodiversity credits aim to mobilise conservation finance by quantifying and trading measurable biodiversity gains. However, attempts to model these credits similar to carbon markets with a single unit face major limitations due to biodiversity’s multidimensional and context-dependent nature. Over-standardization risks stripping ecological complexity and intrinsic value, while excessive detail can make metrics impractical for market use.
Rather than pursuing a single universal biodiversity metric, the authors advocate focusing on harmonizing data collection and processing protocols across projects. This would allow for flexibility in metrics while ensuring datasets remain comparable, transparent, and usable, minimizing confusion across diverse metrics in different scales and different methodologies. However, such an approach requires transparent governance based on high integrity.
“Major international bodies like the International Advisory Panel on Biodiversity Credits (IAPB), the World Economic Forum, and the UNEP-supported Biodiversity Credit Alliance recently set out guidance but the real test is turning those principles into action, and we’re not there yet,” warns Professor Franziska Schrodt, senior author of the study.
Dr Eun Kim, lead author of this study said: “Given that the biodiversity credit market is at a critical early stage, low-integrity credits could rapidly undermine the market confidence before it gains momentum and, more importantly, risk further irreplaceable habitat loss.
“We cannot afford to repeat the trial-and-error approach - the hard lessons learned from the carbon market make this clear. The stakes are too high for anything less than rigorous standards from the outset.” The paper stresses the need for systemic transparency and regulatory oversight, warning that poorly enforced regulation undermines credibility.
Journal
Proceedings of the Royal Society B Biological Sciences
Ash dieback and other tree diseases are resulting in significantly more greenhouse gas emissions than previously thought because a large amount of carbon is escaping from woodland soils, a study has found. This is in addition to carbon losses from tens of millions of dying trees and reduced removal of CO2 from the atmosphere due to the widespread deaths of mature ash trees.
The research team led by the UK Centre for Ecology & Hydrology (UKCEH) says that the exponential rise in tree diseases across the world are likely to hamper forests’ ability to help meet net zero plans.
While the loss of carbon from diseased trees themselves and reduced removal of CO2 has been previously noted by scientists, the authors of the latest study say a third impact – the effects on carbon cycling and storage in the surrounding environment – have not been considered before.
“Tree disease is a triple whammy for climate change mitigation,” said UKCEH ecologist Dr Fiona Seaton, who led the study, published in Global Change Biology.
“A lot of future net zero plans assume a certain level of forest carbon sequestration but this is threatened by the exponential increase in tree diseases such as ash dieback in Britain and across the world.”
Widespread deaths of trees
An estimated nine million trees have so far died in British woodlands as a result of ash dieback, with up to 100 million others expected to be lost over the next 30 years. The disease is therefore going to continue to have significant impacts on woodlands’ ability to store and remove the greenhouse gas and mitigate climate change.
Organic carbon underpins the entire soil food web, so any loss will have negative impacts upon ecosystem services. But the study authors, from UKCEH as well as Lancaster University, the Woodland Trust and University of Oxford, say there is still limited knowledge about the impact of tree diseases on carbon cycling, especially below ground.
They say the difference in the amount of greenhouse gas released and absorbed across woodlands in response to tree disease needs to be better understood.
Jeopardising wildlife
Chris Nichols of the Woodland Trust, a coauthor of the study, said: “Ash are among the most common trees in the UK, and the imported dieback fungus is one of the biggest threats facing British woodlands. Not only does it jeopardise the wildlife that depend on ash, and risk costing the UK billions of pounds in the future, but we are increasingly understanding what dieback could mean for climate change resilience. This kind of research is vital in refining our approach to woodland conservation."
The research was carried out as part of an extensive survey of the physical and chemical composition of Britain’s broadleaf woodlands. The Bunce Survey, led by UKCEH, was carried out at multiple plots on around 100 sites across Britain in 1972, 2001 and most recently in 2022. This unique study shows how our woodlands have changed over the past 50 years due to climate change and land management.
The researchers measured the amount of soil carbon in topsoil in the surveyed woodlands, and compared how soil carbon levels changed in plots with and without ash dieback over the three surveys.
The research was funded by the Woodland Trust and the EU Horizon programme.
- Ends -
Media enquiries
For an interview with one of study authors or further information, please contact Simon Williams, Media Relations Officer at UKCEH, via simwil@ceh.ac.uk or +44 (0)7920 295384.
Paper information
Seaton et al. 2025. Forest topsoil organic carbon declines under ash dieback. Global Change Biology. DOI: 10.1111/gcb.70430. Open access.
Notes to editors
The estimates for soil carbon losses and deaths from ash dieback mentioned in the press release relate to ash trees in British woodlands rather than all individual ash trees everywhere.
The Bunce survey, examining around 100 broadleaf woodlands in different landscapes across Britain, was initially undertaken in 1971 by the late Professor Bob Bunce and the subsequent two resurveys led by Professor Simon Smart of UKCEH. It has found that woods are shadier due to a lack of management over time, with fewer canopy gaps, resulting in woodland composed of fewer but older and larger trees.
A recently published separate analysis of data form the study found that UK woodlands are increasingly under threat from changes in land management, climate, diseases and deer populations – and vegetation is responding differently, requiring tailored action to protect biodiversity.
About the UK Centre for Ecology & Hydrology (UKCEH)
The UK Centre for Ecology & Hydrology (UKCEH) is a leading independent research institute dedicated to understanding and transforming how we interact with the natural world.
With over 600 researchers, we tackle the urgent environmental challenges of our time, such as climate change and biodiversity loss. Our evidence-based insights empower governments, businesses and communities to make informed decisions, shaping a future where both nature and people thrive.
The Woodland Trust is the largest woodland conservation charity in the UK with more than 500,000 supporters. It wants to see a world where woods and trees thrive for people and nature.
Established in 1972, the Woodland Trust now has over 1,000 woodlands in its care, covering more than 30,000 hectares. Access to the Trust’s woods is free so everyone can benefit from woods and trees.
The Trust has three key aims:
• protect ancient woodland, which is rare, unique and irreplaceable
• restoration of damaged ancient woodland, bringing precious pieces of our natural history back to life
• establish native trees and woods with the aim of creating resilient landscapes for people and wildlife
In a new observational study, researchers at Lund University in Sweden looked at all children listed for heart transplants in the Nordic countries between 1986 and 2023. A total of 597 children were included in the study, 461 of whom received a transplant. The results show that survival rates have increased significantly over time despite the modest volumes in the region – a development that the researchers attribute to technological advances, advanced technologies and better healthcare practices.
The study in brief:
597 children were listed for heart transplantation in the Nordic countries between 1986 and 2023, and 461 children (77%) underwent heart transplantation
Mortality among children on the waiting list for heart transplantation fell from 22.8% (1986-1998) to 6.8% (2012-2023)
The long-term survival rate after transplantation was 78% after 10 years. Of the children who have had the opportunity to live 30 years with their new heart, more than half are alive today.
Just over 40% of hearts used for paediatric heart transplantation in Sweden come from donors in other Nordic countries.
The study published in the Journal of Heart and Lung Transplantation is the first of its kind to look at all paediatric heart transplants performed in the Nordic countries, within the framework of the Nordic Scandiatransplant collaboration. The researchers looked at both survival while waiting for transplantation and survival after transplantation.
“The Scandiatransplant countries all have relatively small populations and perform only a small number of paediatric heart transplants each year. We realised that there had never been an overview of the results within Scandiatransplant before, and we were particularly interested in mapping how the results have changed over time and how they fare in an international context, where the comparison is made with larger countries and centres that perform significantly more transplants every year,” says Oscar van der Have, researcher at Lund University and medical registrar at the Children's Heart Centre at Skåne University Hospital and first author of the study.
A previous retrospective study published in 2009 outlined the outcomes after 20 years of heart transplantation practice in Sweden. The current study is an overview of the last 38 years and includes the entire Nordic region divided into three time periods, 1986-1998, 1999-2011 and 2012-2023, to compare outcomes over time. The result that stands out is a significant reduction in mortality while waiting for a new organ, despite the increase in waiting time.
“What is clear from the study is that more children on the waiting list now make it to a heart transplant. In the first time period, 22.8 per cent of children on the waiting list died while waiting for a new heart. In the most recent period, this figure is 6.8 per cent. At the same time, the median waiting time for a new heart has almost doubled – from 38 to 63 days – but despite the longer waiting time, more children are surviving until transplantation,” says Oscar van der Have.
The researchers believe that more children are surviving despite longer waiting times because of technological advances in transplantation care in recent years.
“This is largely down to having better and more advanced technology today. We have short and long-term circulatory support, such as ECMO and mechanical heart pumps, such as the Berlin Heart, which can help children survive the waiting period,” says Karin Tran-Lundmark, researcher and associate professor at Lund University and senior consultant at the Children's Heart Centre at Skåne University Hospital.
Longer waiting times for a new heart and better survival rates may also be partly due to children being put on the waiting list earlier in the course of the disease.
“Another aspect is that we are likely to list the children a little earlier, before they become too ill. This means they have to wait longer – but with better conditions. It is probably an increased awareness: to make the decision earlier, which also allows for improved support during the waiting time,” says Michal Odermarsky, researcher at Lund University and consultant at the Children's Heart Centre at Skåne University Hospital.
Despite the advancements, challenges remain. Long-term survival after transplantation is very good within Scandiatransplant. Despite being small centers with few transplants per year, the outcomes are comparable to much larger centres in, for example, the US, but long-term survival has not improved at the same rate as waiting list survival.
“Unfortunately, lifelong immunosuppressive treatment is needed after a heart transplantation, which carries risks. We need to get even better at detecting and treating complications such as rejection, infections and malignancies. It is important that we follow, and do our best to contribute to, the development of diagnostic methods and medicines,” says Karin Tran-Lundmark.
More knowledge is also needed on how to improve care for the single ventricle patient group:
“We are very interested in the single ventricle patient group, a group of children with severe congenital heart defects. This is our most challenging patient group, where the liver can fail over time due to the heart defect. It can be difficult to decide when it is time to transplant, and whether it is sufficient to replace the heart or whether the liver also needs to be transplanted. There is a lot to consider. It is a small group, but a very complex one,” says Michal Odermarsky.
Another challenge is the availability of organs for the very youngest patients, where mortality on the waiting list remains the highest.
“We also need better solutions for the youngest children. It is difficult to find donors at that age, as, thankfully, we have a low infant mortality rate in the Nordic countries. Increased awareness of the existence of children awaiting transplants may encourage more relatives to donate, and even better heart pumps may also help more patients survive,” Karin Tran-Lundmark suggests.
Facts about Scandiatransplant Scandiatransplant is a Nordic collaboration that coordinates organ transplantation in Denmark, Finland, Norway and Sweden, Iceland and Estonia. The current study does not include listed children from Estonia and Iceland who received heart transplants in Helsinki and Gothenburg.
