Explore the latest insights from top science journals in the Muser Press roundup (June 2, 2026), featuring impactful research on climate change challenges.
In brief:
— Press Release —
How plants learnt to protect themselves from UV rays
Sunlight provides the energy necessary for photosynthesis and growth, but it also exposes plants to harmful ultraviolet-B (UV-B) radiation. Plants must therefore strike a delicate balance between growth and protection. By studying Marchantia polymorpha, a plant similar to some of the earliest land plants, an international team led by scientists from the University of Geneva (UNIGE) sheds light on the evolution of fundamental UV-B perception mechanisms and plant adaptation strategies to light stress. In a context where climate change is altering light exposure conditions, these findings, published in Plant Physiology, could prove particularly valuable.
Light is essential for photosynthesis, the process by which plants produce organic molecules (sugars) and release oxygen. However, it can also be harmful. Like in humans, UV-B radiation can cause DNA damage and harm cell membranes. It can also disrupt the cellular systems responsible for photosynthesis. Over the course of evolution, plants have developed a protective system based on a key photoreceptor called UVR8, which allows them to detect UV-B radiation. When this sensor absorbs UV-B light, it triggers a cascade of molecular reactions that alter the expression of numerous genes, as well as the production of molecules involved in protection and acclimation.
In flowering plants such as Arabidopsis thaliana (thale cress), this signalling pathway involves several regulatory proteins that control genes related to growth and tolerance to light stress. But how did this defence system evolve? The laboratory of Roman Ulm, Full Professor in the Department of Plant Sciences at the Section of Biology, Faculty of Science, UNIGE, focused on the liverwort Marchantia polymorpha, a species belonging to a lineage that emerged when the first plants began colonising land more than 400 million years ago.
An ancestral defence system
The researchers show that the core mechanism activating UVR8 is remarkably conserved between Marchantia and modern flowering plants. This ancestral core includes both the activation of the UVR8 photoreceptor by UV-B radiation and its deactivation mechanism.
However, the study also reveals important changes in how these components interact.
“Our work shows that in Marchantia polymorpha, certain regulatory proteins play roles that differ from those observed in more recent plants. For example, the SPA protein, which works together with the central regulator COP1 in controlling plant growth in Arabidopsis, plays a very different role in Marchantia. While it strongly contributes to developmental regulation in flowering plants, its influence appears much more limited in this ancestral liverwort. Marchantia mutants lacking SPA even show increased tolerance to UV-B, suggesting that this protein acts here as a brake on the protective response,” explain Yuanke Liang and Roman Podolec, postdoctoral researchers in Roman Ulm’s laboratory and co-first authors of the study.
“Our results suggest that while the fundamental ‘building blocks’ of the system were already present very early in plant evolution, their organisation and regulation have been progressively reshaped,” summarises Ulm.
By providing new insights into how plants adapted to light over evolutionary time, this study contributes to a better understanding of plant resilience to environmental stress. In the context of climate change, such knowledge could help anticipate how plants will respond to changing light.
Journal Reference:
Yuanke Liang, Roman Podolec, Richard Chappuis, Emmanuel Defossez, Gaétan Glauser, Johannes Rötzer, Sara Christina Stolze, Liam Dolan, Hirofumi Nakagami, Emilie Demarsy, Roman Ulm, ‘Conservation and divergence of UVR8 photoreceptor-mediated UV-B signaling in Marchantia polymorpha‘, Plant Physiology online, kiag218 (2026). DOI: 10.1093/plphys/kiag218
Article Source:
Press Release/Material by Université de Genève (UNIGE)
— Press Release —
Mapping carbon from ABoVE
In the far north regions of Earth, where forests stretch across Alaska and Canada, climate change is unfolding at an accelerated pace.
Arctic and boreal regions are warming up to four times faster than the global average, putting immense pressure on ecosystems that absorb enormous amounts of CO₂ and help slow climate change. Through photosynthesis, vast expanses of vegetation naturally pull carbon from the atmosphere and sequester it in their biomass.
As climate-related disturbances like wildfires and drought intensify, parts of the region may shift from carbon sinks to carbon sources, disrupting the delicate global carbon balance. Understanding exactly how much carbon these ecosystems store or release through their biomass is important for climate mitigation efforts but getting accurate measurements is a challenge.
Two new papers aim to improve how scientists measure biomass across Arctic and boreal zones. Led by University of Utah biologists Wanwan Liang and Jon Wang, one1 reveals inconsistencies among widely used satellite-based datasets, and the other2 introduces a new biomass map that captures 40 years of ecological change in unprecedented detail.
The research emerged from the Arctic-Boreal Vulnerability Experiment (ABoVE), a NASA-funded, 15-year field research campaign to understand ecosystem change in northern high latitudes.
Making sense of remote sensing
The first study, published in Environmental Research Letters in March 2026, examines the growing number of satellite-based datasets used to map landscapes across Arctic and boreal North America.
“There are so many datasets out there now, but there’s very little guidance for users on how to choose among them,” explained Liang, U postdoctoral researcher and the study’s lead author.
One major contributor to dataset abundance is the rapid advances in remote sensing technology. Satellites continuously capture images of Earth’s surface, and scientists use those data, combined with field measurements, to estimate forest structure, growth and carbon storage.
As the number of datasets has grown, so has confusion about their accuracy and intended use. Different maps often produce different answers, depending on their design, data sources and landscape coverage.
“Two maps can give completely different estimates for the same region and if you’re not an expert, it’s really hard to know which one to trust,” said Wang, assistant professor in the U’s School of Biological Sciences and the study’s principal investigator.
To address that problem, Liang and her collaborators conducted a large-scale meta-analysis, comparing nine biomass datasets across North America’s Arctic and boreal regions. Rather than declaring a single “best” map, the study identifies which datasets are most reliable for specific uses, from tracking wildfire impacts to estimating national carbon budgets.
“It’s more like a guide,” Wang said. “Different maps are better for different purposes.”
Size of a baseball diamond
Liang also led the development of a new biomass dataset, one of the most detailed of its kind. Built using satellite imagery from the NASA/USGS Landsat Program, airborne LiDAR measurements and extensive forest inventory data from the U.S. and Canadian Forest Services, the dataset tracks aboveground biomass annually across nearly four decades. The dataset is described in a paper published in the journal Remote Sensing of Environment on April 30, 2026.
Spanning from 1984 to the present, the map captures changes at a resolution of 30 meters, roughly the size of a baseball diamond. That level of detail allows researchers to detect not only large disturbances like wildfires, but also smaller-scale changes such as logging or land conversion.
“Anything happening at 30 meters or larger, we can detect,” Liang said.
The dataset provides a powerful new lens for understanding how northern ecosystems are responding to climate change. By tracking where biomass is increasing or decreasing, scientists can identify the forces driving those changes, be it drought, fire, human activity, warming temperatures or rising atmospheric CO₂ concentrations.
This matters because Arctic and boreal forests are potential buffers against climate change. As temperatures rise, scientists have hypothesized that these ecosystems could absorb more carbon, helping offset emissions from fossil fuels. But the reality is far more complex.
“There’s been this idea that northern forests will just keep taking up more carbon as it gets warmer,” Wang said. “But we don’t actually know if that’s true.”
The same warming that can stimulate plant growth can also increase wildfire frequency and intensity, insect outbreaks and drought stress – factors that boost forest mortality and release carbon back into the atmosphere.
“If plants start to die, they stop absorbing carbon,” Liang explained. “And as they decompose, they release CO₂. That would accelerate climate change.”
The uncertainty has real-world implications. Governments rely on carbon estimates to inform climate policy and report greenhouse gas inventories. In Canada, for example, national carbon accounting influences how emissions targets are set and evaluated.
“When different datasets give different answers, it creates a lot of uncertainty,” Wang said. “And that makes decision-making harder.”
Beyond policy, high-resolution biomass maps can help estimate how much carbon might be lost in a fire, identify high-risk areas and guide land-use decisions.
In contrast to some private-sector efforts that restrict access to carbon data, Liang and Wang’s project aims to make information transparent and usable for scientists, policymakers and the public.
“This is taxpayer-funded science,” Wang said. “We want people to be able to use it.”
Find the full story at the College of Science.
Journal Reference:
(1) Wanwan Liang, Kirsten Bauck, Devon Maloney, Elizabeth Hoy, Paul Montesano, Mark J Lara, Daryl Yang, Jeremy Forsythe, Laura Duncanson, Xanthe Walker and Jonathan A Wang, ‘Meta-analysis of North American Arctic and boreal aboveground biomass datasets: assessing accuracy, dynamics, and similarities’, Environmental Research Letters 21, 5: 054004 (2026). DOI: 10.1088/1748-9326/ae481a
(2) Wanwan Liang, Olivier van Lier, Mark A. Friedl, James T. Randerson, Brendan M. Rogers, Arden Burrell, Kai-Ting Hu, Piotr Tompalski, Matthew J. Macander, Daryl Yang, Douglas C. Morton, Eric Bullock, Jiaming Lu, Yingtong Zhang, Xiaoran Zhu, Jonathan A. Wang, ‘Derivation and evaluation of Landsat-derived annual aboveground biomass maps for Arctic and Boreal North America, 1984-2022’, Remote Sensing of Environment 341, 115446 (2026). DOI: 10.1016/j.rse.2026.115446
Article Source:
Press Release/Material by Julia St. Andre, College of Science | University of Utah
— Press Release —
Why the Arctic’s rivers are rusting
A new study published in Communications Earth & Environment builds on earlier research documenting widespread contamination in Alaska’s Brooks Range. As the climate warms, a layer of Arctic soil that had been frozen for millennia has begun to thaw. Previous studies suggested that thawing permafrost was the ultimate cause of the damage. This new study proves that beyond a shadow of a doubt.
The new study also reveals two distinct ways in which thawing soil is rusting rivers and helps scientists predict where the damage is likely to spread next.
To investigate the rusting, the research team studied a wide regional view of a vast mountain region, then zoomed in on a specific river system, followed by an even closer look at a single creek. This deep-dive allowed them to connect big patterns to specific, on-the-ground processes.
“At middle, more heavily forested elevations, there isn’t much going on. But at the higher and lower elevations we could see distinctly different phenomena,” said Roman Dial, math and biology professor emeritus at Alaska Pacific University and first author of the study.
At higher elevations, the problem starts in rocky ground containing pyrite, also known as fool’s gold. For many years, because the ground was frozen, water and air didn’t affect the pyrite. Warming and thawing have set into motion a process called acid rock drainage, often associated with mining. However, here it is happening away from mines across a vast, natural, and formerly unspoiled landscape.
“When pyrite meets water, it comes apart. It breaks down into iron and sulfur, creating sulfuric acid as well as sulfate and other toxic metals,” said Tim Lyons, UC Riverside biogeochemist and paper co-corresponding author. “When the iron-rich water mixes with more oxygen, the iron turns into rust-like particles that color the water and stain the bottom sediments orange.”
At lower elevations, the story is different. Here the landscape is covered with wetlands that are changing shape and expanding downward as permafrost melts. In these soggy places, the soils are low in oxygen. So, microbes (mostly bacteria) “breathe” iron instead of oxygen.
“When we breathe, oxygen goes in and gets converted to the carbon dioxide that we exhale,” Dial said. “Similarly, microbes are consuming iron in the lowland soils and converting it into a water-soluble form that seeps into streams and results in rusting as it meets oxygenated surface water.”
Unlike the acid rock drainage, the lowland microbes aren’t directly producing acid or sulfate. That difference is one of the clues researchers used to tell the two processes apart.
Taken together, both help explain why orange waters are appearing across such large regions that now stretch across northern Alaska, closely tracking areas where permafrost is thawing.
The study also reveals a delayed effect that could help predict future contamination. Each summer, the active, top layer of soil thaws to its deepest point before refreezing in winter. Iron released during one thaw can become trapped, then flushed into rivers the following year.
By analyzing long-term ground temperature data alongside stream chemistry, the team found that this lag can be used to anticipate increases in metal levels.
“That means we can use ground temperatures to help predict water quality in the future,” said University of Alaska ecologist and paper co-author Paddy Sullivan, who first noticed the dramatic river changes that looked “like sewage” in 2019 while conducting fieldwork in the region.
Mines typically control the waters near them to minimize pollution. For this study, the team partnered with scientists at the Red Dog zinc mine, who have long-term temperature records from boreholes drilled deeply into the earth and from chemistry sampling in stream water. By linking those underground measurements with changes in stream chemistry, the researchers were able to directly connect thawing permafrost to the rusting rivers.
The ecological consequences of the rusting are severe. Fine iron particles can stay suspended in water for more than 100 kilometers, clouding rivers, smothering algae, disrupting insect populations, and clogging fish gills.
In Alaska and neighboring Canada, the team suspects these changes are affecting salmon, which rely on clean gravel beds for spawning and on algae-based food webs during early life stages.
The findings also suggest the problem will expand globally. Similar conditions involving melting permafrost and metal-rich rocks exist in northern Canada, the Andes, and the Alps, for example.
“It’s already happening in Russia, and will keep happening anywhere you have the right geology and warming temperatures,” Lyons said. “It started as a canary in a coal mine in the Brooks Range, but now those canaries are chirping all over.”
Unlike pollution from mining, which can sometimes be contained, this process is diffuse and difficult to manage. The researchers note that this is happening even in the most remote natural areas of the United States. “You’d think if any ecosystem could hide from the effects of warming and big human footprints, it’d be this one. But it’s not so,” Lyons said. “There is no safe place.”
However, the ability to predict where contamination may occur could help identify and protect critical habitats. Researchers say this is especially important for communities dependent on these waters, and the fish that live in them, for food and cultural practices.
“There’s no fixing this once it starts,” Lyons said. “But we can give people downstream a heads up and work hard to protect the places that are still safe and less vulnerable to the rusting.”
Journal Reference:
Dial, R.J., Hanna, C.T., Sullivan, P.F. et al., ‘Permafrost thaw controls iron flux from wetlands and sulfide-bearing rocks to Arctic rivers and streams’, Communications Earth & Environment 7, 465 (2026). DOI: 10.1038/s43247-026-03450-x
Article Source:
Press Release/Material by Jules Bernstein | University of California – Riverside (UC Riverside)
Featured image credit: Magnific (AI Gen.)
