Explore the latest insights from top science journals in the Muser Press daily roundup (September 15, 2025), featuring impactful research on climate change challenges.
In brief:
Scientists uncover extreme life inside the Arctic ice
If you pull an ice core from the outer edges of the Arctic polar cap, you might spot what looks like a faint line of dirt. Those are diatoms – single-celled algae with outer walls made of glass. Their presence in ice isn’t new, but because they seemed trapped and dormant, few bothered to study them.
But new research from Stanford, published in Proceedings of the National Academy of Sciences, revealed Arctic diatoms aren’t immobile or entombed. They’re not just surviving either – they’re gliding into the record books.
“This is not 1980s-movie cryobiology. The diatoms are as active as we can imagine until temperatures drop all the way down to -15 C, which is super surprising,” said Manu Prakash, associate professor of bioengineering in the Schools of Engineering and Medicine and senior author of the paper.
That temperature (-15 °C | 5 °F) is the lowest ever recorded for movement by a eukaryotic cell – the type of complex cells in plants, animals, fungi, and more, defined by having a nucleus inside a membrane.
“You can see the diatoms actually gliding, like they are skating on the ice,” said lead author and Stanford postdoctoral scholar Qing Zhang, who collected the samples during an Arctic research expedition. She and her colleagues demonstrated not only motility at such low temperatures, but also that their gliding – or skating – relies on a combination of mucus and molecular motors.
Navigating a bustling ’berg
The diatoms featured in this research resulted from a 45-day Arctic expedition in the Chukchi Sea aboard the research vessel Sikuliaq, which is owned by the National Science Foundation and operated by the University of Alaska Fairbanks. Researchers from the Prakash Lab and the lab of Kevin Arrigo, professor of Earth system science in the Stanford Doerr School of Sustainability, collected ice cores from 12 stations throughout the summer of 2023. Using a range of on-ship microscopes that the Prakash Lab has been developing for years, the team was able to image inside ice and document the secret lives of these incredible arctic diatoms.
Back in the lab, the team extracted diatoms from the ice cores and recreated their environments in a petri dish containing a thin layer of frozen freshwater and a layer of very cold saltwater. When ice forms in the Arctic, it kicks out salt, leaving freshwater ice with small microfluidic channels in it – so the lab also made channels in their ice, using their own hair.
Even as they lowered the temperatures of a special sub-zero microscope below freezing, the diatoms slipped through the strand-sized highways. Further experiments, using gels seeded with fluorescent beads, tracked their movements like footprints in sand.
What’s so surprising is the diatoms cruised along without wiggling, scrunching, or use of any appendages. Instead, they practice the art that many diatoms display: gliding.
“There’s a polymer, kind of like snail mucus, that they secrete that adheres to the surface, like a rope with an anchor,” said Zhang. “And then they pull on that ‘rope’ and that gives them the force to move forward.”
The mucilage rope mechanism depends on actin and myosin – the same biological system that drives human muscle movements. How that machinery still works in subzero conditions is now a key research question the lab is pursuing. When the team compared Arctic diatoms with temperate relatives gliding along glass, the polar species moved much faster, hinting at an evolutionary advantage.
The bigger picture
The Prakash Lab made the most of their time in the Arctic and gathered an abundance of data on multiple projects, in addition to diatoms. That includes drone footage, taken under the ice, that vividly displays the potential of this work.
“The Arctic is white on top but underneath, it’s green – absolute pitch green because of the presence of algae,” said Prakash. “In some sense, it makes you realize this is not just a tiny little thing, this is a significant portion of the food chain and controls what’s happening under ice.”
Knowing the diatoms are active raises broader questions about adaptation to a changing polar environment. Could they be moving resources through the Arctic food web, nourishing everything from fish to polar bears? Could their mucus trails even seed new ice formation, the way pearls form around grains of sand?
Normally, Prakash wouldn’t show his hand when it comes to these kinds of nascent ideas, but the stakes this time are different, he said.
“Many of my colleagues are telling me, in the next 25 to 30 years, there will be no Arctic. When ecosystems are lost, we lose knowledge about entire branches in our tree of life,” he said, noting that severe projected budget cuts to the National Science Foundation are predicted to reduce polar research funding by 70 percent. “I feel a sense of urgency in many of these systems, because, at the end of the day, the infrastructure and capacity to be able to operate is critical for discovery.”
Journal Reference:
Q. Zhang, H.T. Leng, H. Li, K.R. Arrigo, & M. Prakash, ‘Ice gliding diatoms establish record-low temperature limits for motility in a eukaryotic cell’, Proceedings of the National Academy of Sciences U.S.A. 122 (37) e2423725122 (2025). DOI: 10.1073/pnas.2423725122
Article Source:
Press Release/Material by Stanford University
Climate change may contribute to new snakebite hotspots in India
India records the highest number of snakebite fatalities worldwide, between 46,000-60,000 annually. A study published in PLOS Neglected Tropical Diseases by Imon Abedin at Dibru-Saikhowa Conservation Society, Tinsukia, India and colleagues suggests that climate change-related shifts in the geographic distribution of venomous snakes will increase the risk of snakebites in certain regions.
The Big Four (Bungarus caeruleus, Daboia russelii, Echis carinatus, and Naja naja) refers to four venomous snake species responsible for the greatest number of medically significant human snakebite cases on the Indian subcontinent. However, how changing geographic distribution of these species due to climate change may affect envenomation risk across India has not been assessed.
In order to better understand how climate change might change different regions’ exposure to venomous snakes, researchers analyzed predictive models visualizing current and future geographic distribution of the Big Four species under different climate scenarios. The researchers then analyzed regional socioeconomic and public health data to develop a snakebite risk index for Indian districts and states over the next 50 years.
The researchers found that climate change may shift geographic distribution of the Big Four into the Northern and Northeastern states increasing snakebite risks in India. The study had several limitations, however, and future studies attempting replication are needed. The accuracy of the prediction models is contingent on data quality and snake occurrence is difficult to document in large, rural regions, leading to potential undercounting. Additionally, the compounded effects of land use change, urbanization, and habitat degradation may limit the value of predictive models on snake distribution.
According to the authors: “Climate change is altering snake species’ geographic ranges, resulting in expansions, contractions, or shifting ranges. Such changes may increase human-snake interactions across rural and urban areas, presenting new challenges for public health and medical management. Consequentially, to mitigate snakebite risk in affected regions, it is essential to implement strategies that enhance decision-making in healthcare delivery, antivenom research, and production capabilities.”
“This is the first study in India to integrate climate-based species distribution models with socioeconomic vulnerability and healthcare capacity,” the authors noted. “It shows that climate change is not just an environmental crisis but it’s also a looming public health crisis.”
Journal Reference:
Abedin I, Kang H-E, Saikia H, Jung W-K, Kim H-W, Kundu S, ‘Future of snakebite risk in India: Consequence of climate change and the shifting habitats of the big four species in next five decades’, PLOS Neglected Tropical Diseases 19 (9): e0013464 (2025). DOI: 10.1371/journal.pntd.0013464
Article Source:
Press Release/Material by PLOS
PolyU researchers use novel satellite laser ranging technique to reveal accelerated global average sea-level rise with 90 mm surge over past 30 years
The rise in global mean sea level (GMSL) is a critical indicator of climate change. The Hong Kong Polytechnic University (PolyU) researchers have utilised advanced space geodetic technologies to deliver the first precise 30-year (1993-2022) record of global ocean mass change (also known as barystatic sea level), revealing its dominant role in driving GMSL rise.
Their research further indicates that GMSL has been increasing at an average rate of approximately 3.3 mm per year with a notable acceleration observed, highlighting the growing severity of climate change. The research findings have been published in the Proceedings of the National Academy of Sciences.
GMSL is primarily driven by two factors: the thermal expansion of seawater – as the oceans absorb around 90% of the excess heat in the Earth’s climate system – and the increase in global ocean mass, which is mainly caused by the influx of freshwater from melting land ice. Therefore, long-term monitoring of global ocean mass change is essential for understanding present-day GMSL rise.
A research team led by Prof. Jianli Chen, Chair Professor of Space Geodesy and Earth Sciences of the PolyU Department of Land Surveying and Geo-Informatics (LSGI) and a core member of the PolyU Research Institute for Land and Space, together with Dr Yufeng Nie, Research Assistant Professor of LSGI and the lead and corresponding author of the research, has, for the first time, provided direct observations of global ocean mass estimates between 1993 and 2022 by utilising time-variable gravity field data derived from satellite laser ranging (SLR).
In the past, scientists have relied on long-term observations from satellite altimetry to project sea-level rise. Barystatic sea level records based on satellite gravimetry only became available with the launch of the Gravity Recovery and Climate Experiment in 2002.
SLR is a traditional space geodetic technique used to accurately measure the distance between satellites and ground stations via laser ranging. However, fundamental constraints of SLR, such as the limited number of satellites and ground stations, the high altitude of the satellites (which means SLR-derived gravitational changes capture only the longest wavelengths) and the low-degree gravitational measurements, have restricted its direct application in estimating ocean mass change.
To effectively utilise SLR-derived gravitational fields for accurate estimates of ocean mass change, the research team implemented an innovative forward modelling technique that tackles spatial resolution limitations by incorporating detailed geographic information of ocean-land boundaries. This approach enables long-term monitoring of global ocean mass changes.
The research revealed that an increased rate of GMSL resulted in a global average sea-level rise of approximately 90 mm between 1993 and 2022, with about 60% of this rise attributable to ocean mass increase. Since around 2005, the rise in GMSL has been primarily driven by the rapid increase in global ocean mass. This overall increase is largely driven by the accelerated melting of land ice, particularly in Greenland. Throughout the entire study period, land ice melt from polar ice sheets and mountain glaciers accounted for over 80% of the total increase in global ocean mass.
Prof. Jianli Chen said: “In recent decades, climate warming has led to accelerated land ice loss, which has played an increasingly dominant role in driving global sea-level rise. Our research enables the direct quantification of global ocean mass increase and provides a comprehensive assessment of its long-term impact on sea-level budget. This offers crucial data for validating coupled climate models used to project future sea-level rise scenarios.”
Dr Yufeng Nie added: “The research showed that the ocean mass changes derived from SLR analysis align well with the total sea level changes observed by satellite altimeters, after accounting for the effect of ocean thermal expansion. This demonstrates that the traditional SLR technique can now serve as a novel and powerful tool for long-term climate change studies.”
Journal Reference:
Y. Nie, J. Chen, G. Xu, & A. Löcher, ‘Barystatic sea level change observed by satellite gravimetry: 1993–2022’, Proceedings of the National Academy of Sciences U.S.A. 122 (27) e2425248122 (2025). DOI: 10.1073/pnas.2425248122
Article Source:
Press Release/Material by The Hong Kong Polytechnic University
HKU ecologists link arthropod declines and ecosystem function loss in tropical rainforests to intensifying El Niño events
A new study published in Nature, led by ecologists from the School of Biological Sciences (SBS) at The University of Hong Kong (HKU), finds that intensifying El Niño events, driven by climate change, are disrupting arthropod populations across the tropics. This hidden collapse threatens the stability of entire ecosystems and the essential services they provide to both nature and people.
Arthropods, tiny but vital creatures, including insects and spiders, make up the vast majority of animal species on Earth. They are irreplaceable contributors, playing a crucial role in maintaining healthy ecosystems and serving as vital food sources for birds and other larger animals.
While arthropod declines in temperate regions of the Northern Hemisphere have garnered attention in recent years, their rapid disappearance from tropical rainforests, even in pristine areas untouched by human activity, has largely gone unnoticed. These rainforests, the most bio-diverse ecosystems on Earth, remain understudied, and the consequences of biodiversity loss are still poorly understood.
A hidden biodiversity crisis unfolds in tropical rainforests
An international team of scientists set out to uncover this missing evidence. The study was led by researchers from the Biodiversity and Environmental Change Lab and the Global Change and Tropical Conservation group at HKU, who conducted a large-scale analysis of tropical rainforest arthropods and the essential ecological roles they perform.
Combining information from over 80 previous studies in tropical rainforest sites that have never been commercially altered by humans, the team found significant biodiversity loss in multiple types of arthropods.
“To find such large declines across so many different studies is really bad news,” says Dr Adam Sharp, Post-doctoral Fellow of HKU SBS, lead author and data analyst. “Our results strongly suggest that the immense biodiversity of tropical rainforest arthropods is under immediate threat. Since all of the data we used comes from rainforests considered ‘untouched’, it means even the deepest and darkest tropical rainforests are likely to be heavily impacted.”
The declines were not random. The study identified a key driver: changes in El Niño–Southern Oscillation (ENSO), which regulates tropical climate from year to year.
“We believe the increasing frequency of El Niño is driving these widespread arthropod declines,” says corresponding author Dr Michael Boyle, Research Fellow at HKU SBS. “In these tropical rainforests that haven’t otherwise been physically modified by humans, we can rule out habitat loss, pesticides, pollution and various other threats. In these places, El Niño seems to be the prime suspect.”
These climate-driven declines are not just biological – they are functional. The study found that two critical ecosystem processes, decomposition and herbivory, are already weakening.
Key findings of the study
- Tropical invertebrates are in decline: Five out of nine major invertebrate groups – including butterflies, beetles, spiders, ants, and bugs – are showing long-term species losses, even in undisturbed rainforests.
- Climate change is disrupting natural climate cycles: Arthropods rely on the balance between hot, dry El Niño and cooler, wetter La Niña years – part of the El Niño–Southern Oscillation (ENSO). But climate change is making El Niño events more frequent and intense, tipping the balance and driving long-term declines, especially in species that depend on La Niña conditions.
- Ecosystem functions are weakening: These biodiversity losses are linked to significant reductions in leaf litter decomposition and herbivory, processes critical to rainforest health.
- Specialist species are most vulnerable: Arthropods with narrow diets or specific ecological roles are at higher risk of disappearing.
- Warning signs of instability: Increasing year-to-year fluctuations in species diversity for some arthropod groups, suggests that tropical ecosystems may be losing stability, with potential long-term consequences for biodiversity and ecosystem functioning.
The international team is carrying out resampling of rainforest arthropods across Australia, Malaysia and mainland China to better understand how they are changing through time, even within protected areas.
Journal Reference:
Sharp, A.C., Boyle, M.J.W., Bonebrake, T.C. et al., ‘Stronger El Niños reduce tropical forest arthropod diversity and function’, Nature (2025). DOI: 10.1038/s41586-025-09351-x
Article Source:
Press Release/Material by The University of Hong Kong
Featured image credit: Gerd Altmann | Pixabay
