“Everyone knows that the woolly mammoth went extinct, but virtually no-one mentions the plants that were lost at the end of the last ice age,” says Prof Ulrike Herzschuh from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). “Until recently, we lacked suitable methods for investigating the extinction of plant species in detail.” In terms of fossil plant remains, mainly pollen was used, which doesn’t allow individual species to be identified and therefore offers no evidence of which species have died out.”Using cutting-edge methods, we analysed old DNA from sediment cores taken from lakes in Alaska and Siberia, which allowed us to reconstruct the changes in vegetation in these regions.” The cores contain fragmented DNA from deposited plant biomass from the past 30,000 years, which the experts enriched, sequenced, and compared with databases for identification purposes at special-purpose labs for old DNA.

Temperature can change how plants interact

“We’ve now been able to determine in detail when and where species appeared and disappeared in Alaska and Siberia,” says Ulrike Herzschuh. “Our research shows that the composition of plant species changed substantially at the end of the last ice age, and that this was accompanied by fundamental changes in the ecological conditions.” The researchers identified a connection between temperature and plant-to-plant interactions: in cold climate periods, plant species support one another, while they mainly compete during warm periods. “In the DNA from the lake sediments, we found e.g. many cushion plants, which most likely supported the expansion of other species by forming sheltered habitats,” says Ulrike Herzschuh. This has effects on both biodiversity and richness range size.

In a warmer climate, woody plant species dominate: ‘Today, we see that plant diversity declines due to the migration of trees and shrubs into tundra regions, whereas during cold periods, higher plant diversity prevailed.

What does that tell us about vegetation changes in the high latitudes, where cushion plants still play a pivotal role today? In today’s Arctic, this supportive quality could actually threaten their own survival. “Since the warming of the Arctic has already progressed quite far, woody plants can survive even in the high latitudes. The cushion plants could facilitate their spreading, hastening their own extinction in the process.”

Which plant species are particularly at risk?

The end of the last ice age also caused some types of vegetation to disappear entirely — as the experts were able to confirm using their new methods. Take the mammoth steppe, for example: during the last ice age, this type of vegetation spread across the Northern Hemisphere, only to die out during the transition to the current age. In this regard, identifying the extinct plant species was especially challenging. “To identify the species that no longer existed, we had to use a trick,” Ulrike Herzschuh explains. Normally, species are identified on the basis of DNA fragments, which are compared with the entries in genetic databases. But these databases include information on today’s plants, not on extinct species. “We examined all the DNA fragments from our cores and then used statistical models to filter out those with unmistakeable similarities to modern plants, step by step.”

This also allowed the experts to determine which species could be at the greatest risk of extinction in a warming world: grasses and shrubs are at a higher risk of disappearing than woody plant species, which can spread further when temperatures rise. In addition, species in regions with high biodiversity are more often at risk than are less “special” species. One surprising finding: the extinction rate was at its highest at the beginning of the current warm phase — often with a delay of several thousand years after the actual environmental changes. “That means the full impacts of today’s human activities might not become apparent until the distant future.”

Relevance for today’s Arctic

The results of the two studies offer fundamental insights into how environmental changes in connection with warming affect biodiversity, and which mechanisms are central in this regard. As such, for the first time the experts were able to determine extinction rates for plants, which can now be used as reference data to better assess the ongoing changes in Arctic ecosystems. “Our studies show how important it is to understand biodiversity and ecological interactions, also in the long term, in order to better predict the impacts of climate change,” Ulrike Herzschuh summarises. “Using the information locked in old DNA from sediments, we can gain the fundamental knowledge needed to do so.”

A new study published in the journal Science Advances by an international team of climate scientists presents the first realistic supercomputer simulation that resolves the complex interactions between fire, vegetation, smoke and the atmosphere. The authors find that increasing greenhouse gas emissions will likely increase the global lightning frequency by about 1.6% per degree Celsius global warming, with regional hotspots in the eastern United States, Kenya, Uganda and Argentina. Locally this could intensify wildfire occurrences. However, the dominant drivers for the growing area burned by fires each year remain shifts in global humidity and a more rapid growth of vegetation, which can serve as wildfire fuel.

The study further identifies regions, where the intensification of fires caused by global warming will be most pronounced. Among the regions exhibiting the strongest anthropogenic trends in biomass burning are southern and central equatorial Africa, Madagascar, Australia, parts of the Mediterranean and western North-America. “Our results show that with every degree global warming the global mean area burned by fires each year will increase by 14%. This can have substantial effects on ecosystems, infrastructure and human health and livelihoods.” says Dr. Vincent VERJANS, former postdoctoral research fellow at the IBS Center for Climate Physics (now at Barcelona Supercomputing Center) and lead author of the study.

Moreover, the researchers also highlight that with more fires on a global scale, also the levels of fire smoke will increase. Smoke plumes emerging from wildfires will have an effect on air pollution and also lead to reduced penetration of sunlight. The latter changes the heat and infrared radiation in the atmosphere. “Our new computer model simulations show for the first time that accounting for these effects in a comprehensive earth system model, can influence regional temperatures. Fire regions and their downwind smoke plume extensions will experience on average somewhat reduced warming due to the solar dimming effect.” says co-author Prof. Christian FRANZKE from the IBS Center for Climate Physics at Pusan National University, South Korea. However, in addition to reducing sunlight (direct aerosol effect) which is accounted for in the new computer simulations, aerosols from biomass burning can also change the formation of clouds (indirect effect). “This part is still somewhat uncertain, and more research needs to be conducted to understand how fires will impact clouds and subsequently surface temperatures,” adds Prof. Franzke.

While this study makes important strides in representing climate-lightning-wildfire interactions in the current generation of Earth System models, it also identifies key aspects that require further consideration. A critical example is the extent to which Arctic wildfires will increase in a warmer world. In their model simulations, the increase in Arctic wildfire activity is weaker than the observed trends in recent years. “This may indicate that current climate models underestimate future Arctic wildfire risks. Among other things, this would have important consequences for predictions of aerosols released from wildfires, which in turn will affect the climate and influence air quality,” says Dr. Vincent VERJANS.

The detected event was identified as a single muon which crossed the entire detector, inducing signals in more than one third of the active sensors. The inclination of its trajectory combined with its enormous energy provides compelling evidence that the muon originated from a cosmic neutrino interacting in the vicinity of the detector.

“KM3NeT has begun to probe a range of energy and sensitivity where detected neutrinos may originate from extreme astrophysical phenomena. This first ever detection of a neutrino of hundreds of PeV opens a new chapter in neutrino astronomy and a new observational window on the Universe,” comments Paschal Coyle, KM3NeT Spokesperson at the time of the detection, and researcher at CNRS Centre National de la Recherche Scientifique — Centre de Physique des Particules de Marseille, France.

The high-energy universe is the realm of cataclysmic events such as accreting supermassive black holes at the centre of galaxies, supernova explosions, gamma ray bursts, all as yet not fully understood. These powerful cosmic accelerators, generate streams of particles called cosmic rays. Some cosmic rays may interact with matter or photons around the source, to produce neutrinos and photons. During the travel of the most energetic cosmic rays across the Universe, some may also interact with photons of the cosmic microwave background radiation, to produce extremely energetic “cosmogenic” neutrinos.

“Neutrinos are one of the most mysterious of elementary particles. They have no electric charge, almost no mass and interact only weakly with matter. They are special cosmic messengers, bringing us unique information on the mechanisms involved in the most energetic phenomena and allowing us to explore the farthest reaches of the Universe,” explains Rosa Coniglione, KM3NeT Deputy-Spokesperson at the time of the detection, researcher at the INFN National Institute for Nuclear Physics, Italy.

Although neutrinos are the second most abundant particle in the Universe after photons, their weak interaction with matter makes them very hard to detect and requires enormous detectors. The KM3NeT neutrino telescope, currently under construction, is a giant deep-sea infrastructure distributed across two detectors ARCA and ORCA. In its final configuration, KM3NeT will occupy a volume of more than one cubic kilometre. KM3NeT uses sea water as the interaction medium for neutrinos. Its high-tech optical modules detect the Cherenkov light, a bluish glow that is generated during the propagation through the water of the ultra-relativistic particles produced in neutrino interactions.

“To determine the direction and energy of this neutrino required a precise calibration of the telescope and sophisticated track reconstruction algorithms. Furthermore, this remarkable detection was achieved with only one tenth of the final configuration of the detector, demonstrating the great potential of our experiment for the study of neutrinos and for neutrino astronomy,” comments Aart Heijboer, KM3NeT Physics and Software Manager at the time of the detection, and researcher at Nikhef National Institute for Subatomic Physics, The Netherlands.

The KM3NeT/ARCA (Astroparticle Research with Cosmics in the Abyss) detector is mainly dedicated to the study of the highest energy neutrinos and their sources in the Universe. It is located at 3450 m depth, about 80 km from the coast of Portopalo di Capo Passero, Sicily. Its 700 m high detection units (DUs) are anchored to the seabed and positioned about 100 m apart. Every DU is equipped with 18 Digital Optical Modules (DOM) each containing 31 photomultipliers (PMTs). In its final configuration, ARCA will comprise 230 DUs. The data collected are transmitted via a submarine cable to the shore station at the INFN Laboratori Nazionali del Sud.

The KM3NeT/ORCA (Oscillation Research with Cosmics in the Abyss) detector is optimised to study the fundamental properties of the neutrino itself. It is located at a depth of 2450 m, about 40 km from the coast of Toulon, France. It will comprise 115 DUs, each 200 m high and spaced by 20 m. The data collected by ORCA are sent to the shore station at La Seyne Sur Mer.

“The scale of KM3NeT, eventually encompassing a volume of about one cubic kilometre with a total of about 200,000 photomultipliers, along with its extreme location in the abyss of the Mediterranean Sea, demonstrates the extraordinary efforts required to advance neutrino astronomy and particle physics. The detection of this event is the result of a tremendous collaborative effort between many international teams of engineers, technicians and scientists,” comments Miles Lindsey Clark, KM3NeT Technical Project Manager at the time of the detection, and research engineer at the CNRS — Astroparticle and Cosmology laboratory, France.

This ultra-high energy neutrino may originate directly from a powerful cosmic accelerator. Alternatively, it could be the first detection of a cosmogenic neutrino. However, based on this single neutrino it is difficult to conclude on its origin. Future observations will focus on detecting more such events to build a clearer picture. The ongoing expansion of KM3NeT with additional detection units and the acquisition of additional data will improve its sensitivity and enhance its ability to pinpoint cosmic neutrino sources, making it a leading contributor to multi-messenger astronomy.

The KM3NeT Collaboration brings together more than 360 scientists, engineers, technicians and students of 68 institutions from 21 countries all over the world.

KM3NeT is included in the roadmap of the European Strategy Forum on Research Infrastructures, which recognises KM3NeT as a priority research infrastructure for Europe. In addition to the funding provided by research agencies in several countries, KM3NeT has benefitted from various fundings through the European research and innovation programmes as well as the European Regional Development Fund.

Vimentin is a type III intermediate filament (IF) protein normally expressed in cells that develop into connective tissue, blood vessels, and lymphatic tissue (mesenchymal cells). Despite being widely studied, its role in tumour growth and progression remains unexplored.

A team of researchers at Queen Mary University of London have discovered how a small change in the vimentin protein can make breast cancer more aggressive. By modifying a specific amino acid cysteine to serine residue at position 328 in vimentin, they discovered that this mutation disrupted the protein’s interaction with the cell’s structural network. Remarkably, the mutated vimentin induced aggressive cancer-like behaviour in breast cancer cells, including faster cell growth, migration, and invasion accompanied by reduced cell adhesion. RNA-sequencing further revealed that the presence of mutant vimentin was associated with upregulation of a non-coding RNA called XIST, suggesting a potential link between this mutation and gene expression changes that drive cancer progression.

Researchers also found that mutant vimentin made breast cancer cells grow without depending on the hormone oestrogen when injected into immuno-compromised mice. The tumours in these mice showed high expression of cancer stem cell markers CD56 and CD20, suggesting a role for mutant vimentin in driving cancer stem cell-like behaviour that is often associated with tumour progression, therapeutic resistance and recurrence.

Senior author Ahmad Waseem, Professor of Molecular and Cellular Oral Biology at the Institute of Dentistry, Queen Mary University of London, said: “Our study has discovered a molecular interaction that, when disrupted, causes breast cancer cells to behave like cancer stem cells. Additionally, we identified a potential biomarker that could help detect these stem-like cells in breast cancer tissues. This discovery represents an important step towards understanding how breast cancer develops and spreads, with potential implications for early diagnosis, prognosis, and targeted treatment strategies.” The lead author, Dr Saima Usman (HEC Fellow), did her PhD with Professor Waseem on this project.

Co-author Andrew Yeudall, Professor of Oral Biology in the Dental College of Georgia at Augusta University, said: “The study will open new avenues for our understanding of cancer stem cell behaviour. For several years, Professor Waseem and I have been interested in studying the cancer-related roles of vimentin, which is induced in almost all later-stage tumours that have spread to other sites in the body and can be difficult to treat. We used MCF-7, a model breast epithelial cell line, partly because it is devoid of vimentin which therefore makes it easier to define functions related to specific vimentin mutations. Our observation that the cells became more aggressive, and that stem cell markers were induced, may unlock the door to new therapeutic approaches for breast and other cancers.”