The ocean around Antarctica is rapidly getting saltier at the same time as sea ice is retreating at a record pace. Since 2015, the frozen continent has lost sea ice similar to the size of Greenland. That ice hasn’t returned, marking the largest global environmental change during the past decade.
This finding caught us off guard – melting ice typically makes the ocean fresher. But new satellite data shows the opposite is happening, and that’s a big problem. Saltier water at the ocean surface behaves differently than fresher seawater by drawing up heat from the deep ocean and making it harder for sea ice to regrow.
The loss of Antarctic sea ice has global consequences. Less sea ice means less habitat for penguins and other ice-dwelling species. More of the heat stored in the ocean is released into the atmosphere when ice melts, increasing the number and intensity of storms and accelerating global warming. This brings heatwaves on land and melts even more of the Antarctic ice sheet, which raises sea levels globally.
Our new study has revealed that the Southern Ocean is changing, but in a different way to what we expected. We may have passed a tipping point and entered a new state defined by persistent sea ice decline, sustained by a newly discovered feedback loop.
The Southern Ocean surrounds Antarctica, which is fringed by sea ice.Nasa
A surprising discovery
Monitoring the Southern Ocean is no small task. It’s one of the most remote and stormy places on Earth, and is covered in darkness for several months a year. Thanks to new European Space Agency satellites and underwater robots which stay below the ocean surface measuring temperature and salinity, we can now observe what is happening in real time.
Our team at the University of Southampton worked with colleagues at the Barcelona Expert Centre and the European Space Agency to develop new algorithms to track ocean surface conditions in polar regions from satellites. By combining satellite observations with data from underwater robots, we built a 15-year picture of changes in ocean salinity, temperature and sea ice.
What we found was astonishing. Around 2015, surface salinity in the Southern Ocean began rising sharply – just as sea ice extent started to crash. This reversal was completely unexpected. For decades, the surface had been getting fresher and colder, helping sea ice expand.
The annual summer minimum extent of Antarctic sea ice dropped precipitously in 2015.NOAA Climate.gov/National Snow and Ice Data Center
To understand why this matters, it helps to think of the Southern Ocean as a series of layers. Normally, the cold, fresh surface water sits on top of warmer, saltier water deep below. This layering (or stratification, as scientists call it) traps heat in the ocean depths, keeping surface waters cool and helping sea ice to form.
Saltier water is denser and therefore heavier. So, when surface waters become saltier, they sink more readily, stirring the ocean’s layers and allowing heat from the deep to rise. This upward heat flux can melt sea ice from below, even during winter, making it harder for ice to reform. This vertical circulation also draws up more salt from deeper layers, reinforcing the cycle.
A powerful feedback loop is created: more salinity brings more heat to the surface, which melts more ice, which then allows more heat to be absorbed from the Sun. My colleagues and I saw these processes first hand in 2016-2017 with the return of the Maud Rise polynya, which is a gaping hole in the sea ice that is nearly four times the size of Wales and last appeared in the 1970s.
What happens in Antarctica doesn’t stay there
Losing Antarctic sea ice is a planetary problem. Sea ice acts like a giant mirror reflecting sunlight back into space. Without it, more energy stays in the Earth system, speeding up global warming, intensifying storms and driving sea level rise in coastal cities worldwide.
Wildlife also suffers. Emperor penguins rely on sea ice to breed and raise their chicks. Tiny krill – shrimp-like crustaceans which form the foundation of the Antarctic food chain as food for whales and seals – feed on algae that grow beneath the ice. Without that ice, entire ecosystems start to unravel.
What’s happening at the bottom of the world is rippling outward, reshaping weather systems, ocean currents and life on land and sea.
Feedback loops are accelerating the loss of Antarctic sea ice.University of Southampton
Antarctica is no longer the stable, frozen continent we once believed it to be. It is changing rapidly, and in ways that current climate models didn’t foresee. Until recently, those models assumed a warming world would increase precipitation and ice-melting, freshening surface waters and helping keep Antarctic sea ice relatively stable. That assumption no longer holds.
Our findings show that the salinity of surface water is rising, the ocean’s layered structure is breaking down and sea ice is declining faster than expected. If we don’t update our scientific models, we risk being caught off guard by changes we could have prepared for. Indeed, the ultimate driver of the 2015 salinity increase remains uncertain, underscoring the need for scientists to revise their perspective on the Antarctic system and highlighting the urgency of further research.
We need to keep watching, yet ongoing satellite and ocean monitoring is threatened by funding cuts. This research offers us an early warning signal, a planetary thermometer and a strategic tool for tracking a rapidly shifting climate. Without accurate, continuous data, it will be impossible to adapt to the changes in store.
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This article is republished from The Conversation under a Creative Commons license. Read the original article.
Alessandro Silvano is a Natural Environment Research Council (United Kingdom Research and Innovation) Independent Research Fellow.
NASA’s Perseverance rover is digging deeper into Mars’ geologic past as it begins grinding into Red Planet rock surfaces to expose material that could hold clues to the planet’s ancient environment and habitability.
Earlier this month, the Perseverance rover used its abrasion tool to scrape away the top layer of a rocky Martian outcrop nicknamed “Kenmore,” revealing a fresh surface for close-up analysis of the rock’s composition and history. The procedure, which involves a combination of mechanical grinding and gas-blast cleaning, allows scientists to study rock interiors that haven’t been altered by wind, radiation or dust over billions of years.
“Kenmore was a weird, uncooperative rock,” Ken Farley, Perseverance’s deputy project scientist, said in a statement. “Visually, it looked fine — the sort of rock we could get a good abrasion on and perhaps, if the science was right, perform a sample collection. But during abrasion, it vibrated all over the place and small chunks broke off. Fortunately, we managed to get just far enough below the surface to move forward with an analysis.”
The recent abrasion marks a shift in the rover’s focus from primarily scouting and sampling to more detailed in-situ science. Compared to its predecessors, Perseverance uses an advanced abrading bit and gaseous Dust Removal Tool, or gDRT, which applies five puffs of nitrogen to clear samples in a way that poses less risk of contamination. For comparison, earlier rovers used a brush instead to sweep debris, or tailings, out of the way.
(Image credit: NASA/JPL-Caltech)
After an abrasion is complete, Perseverance’s science instruments are deployed to investigate the exposed rock. The rover’s WATSON (Wide Angle Topographic Sensor for Operations and Engineering) imager snaps close-up photos, while its SuperCam uses laser pulses to analyze the composition of vaporized material with one spectrometer and study visible and infrared light reflected from the freshly exposed surface with another.
“The tailings showed us that this rock contains clay minerals, which contain water as hydroxide molecules bound with iron and magnesium — relatively typical of ancient Mars clay minerals.” Cathy Quantin-Nataf, SuperCam team member, said in the statement. “The abrasion spectra gave us the chemical composition of the rock, showing enhancements in iron and magnesium.”
Perseverance also relies on its SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) and PIXL (Planetary Instrument for X-ray Lithochemistry) instruments to help determine mineral content, chemical composition and potential signs of past water activity or even microbial life. In fact, not only did these tools find further evidence of clay, they also detected feldspar — a mineral common in Earth’s crust as well as on the moon and other rocky planets. The team also found, for the first time, manganese hydroxide in the observed specimens.
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“The data we obtain now from rocks like Kenmore will help future missions so they don’t have to think about weird, uncooperative rocks,” Farley said. “Instead, they’ll have a much better idea whether you can easily drive over it, sample it, separate the hydrogen and oxygen contained inside for fuel, or if it would be suitable to use as construction material for a habitat.”
The work is being carried out in Mars’ Jezero Crater, a 28-mile-wide (45-kilometer-wide) basin that once hosted a river delta and lake. Scientists believe the region contains some of the best-preserved records of Mars’ wet past, making it a prime location to search for biosignatures, or indicators of ancient life. Kenmore represents the 30th Martian rock that Perseverance has studied in such fine detail.
Perseverance is also continuing to collect rock core samples, which are being sealed in tubes and stored for a possible future return to Earth through the planned Mars Sample Return (MSR) campaign — though the Trump administration’s recently released FY 2026 NASA budget proposal suggests cutting the MSR program altogether.
As cities rapidly grow, expanding by an area almost double the size of France by 2030, natural spaces are being replaced by buildings and roads. This massive urban spread is hitting wildlife hard, wiping out their homes, cranking up temperatures, and creating dangerous concrete jungles.
It’s a tough situation for many animals on the move. Cities can be tempting with easy food and fewer natural predators, but they also come with deadly risks like traffic and lost pathways.
While past studies used cameras or sound to monitor urban wildlife, a new Yale study takes a different approach by analyzing environmental DNA (eDNA) from soil in 21 Detroit parks during winter and summer to uncover how mammal diversity changes with the seasons in urban landscapes.
The study aimed to understand how human activity shapes mammal communities in urban areas. By sampling environmental DNA (eDNA) from soil across 21 Detroit parks, researchers uncovered subtle, park-specific shifts in species composition, influenced by both natural and human-related factors, and larger parks supported greater biodiversity.
eDNA revealed seasonal changes and human presence effects on urban wildlife. These insights offer a promising tool for more adaptive and informed urban biodiversity planning, helping cities better balance green space with growing human footprints.
Measuring the effects of natural events on wildlife
Researchers analyzed soil samples from 21 urban parks in Detroit, Michigan, during February and July 2023. They detected DNA from 23 mammal species, including humans. They confirmed these results using iNaturalist wildlife sightings.
The DNA samples revealed seasonal shifts in mammal presence. Hibernators like groundhogs and muskrats were absent in winter samples, reflecting seasonal behaviors. During winter, animals were more clustered, likely due to resource competition and limited movement.
In summer, eDNA patterns revealed that mammals were more dispersed across landscapes, with fewer cross-species interactions due to abundant resources. Larger parks supported wider-ranging species, and coyotes appeared only in parks over 14.4 hectares.
Human DNA made up about one-third of all samples, highlighting constant human presence. Domesticated animal DNA (from cats, dogs, pigs, and cattle) reinforced the idea that urban parks are shared socio-ecological spaces.
Human presence influenced wildlife makeup, generalist and human-tolerant mammals thrived in busier areas, while more sensitive species were less commonly detected.
To protect urban biodiversity, especially wide-ranging species, researchers recommend expanding green spaces and building wildlife corridors that link parks together.
As cities continue to grow, these connected landscapes could be key to maintaining resilient ecosystems that support both nature and human well-being.
Journal Reference
Jane Hallam and Nyeema C. Harris. Network dynamics revealed from eDNA highlight seasonal variation in urban mammal communities. Journal of Animal Ecology. DOI: 10.1111/1365-2656.70082
A sea lion shows symptoms of domoic acid poisoning during a harmful algae bloom in Malibu, California, on April 24, 2002.
After starting her PhD studies in 2018, Monica Thukral would go for a swim off the coast of San Diego two to three times a week. The regular, physical connection with the waters helped to anchor her in her research at the University of California San Diego’s Scripps Institution of Oceanography.
“I had an understanding of the physical processes: how the temperature and the wave energy change throughout the year,” Thukral recalls. “I was the first to know when an algae bloom was taking place.”
In the laboratory, Thukral transformed that intuition into something more systematic. Using cutting-edge analytical tools, her team in the environmental systems biology lab of Andrew E. Allen—who also teaches at the nearby J. Craig Venter Institute, a genomics research foundation—strove to understand what was happening in the water on a molecular level.
The scientists were working in the wake of a momentous oceanographic event. In 2015, a massive harmful algal bloom (HAB) had subsumed a stretch of Pacific coastline from southern California all the way to Alaska’s Aleutian Islands. It flooded the region’s waters with domoic acid, a neurotoxin so dangerous that it gives sea lions epilepsy; government regulators shuttered some commercial fisheries for months.
How do you place a value on the loss of shellfish that you’ve been harvesting for centuries with your family?
Vera Trainer, Director, University of Washington’s Olympic Region Harmful Algal Bloom program
Produced by microalgae—namely, several species of marine diatoms known as Pseudo-nitzschia—domoic acid can bioaccumulate in the marine food web, eventually getting consumed by humans, in whom it can cause nausea, cardiac arrhythmia, and a condition called amnesic shellfish poisoning, which can include memory loss and disorientation. Once the acid has accumulated in shellfish tissues past an official threshold of 20 parts per million, regulators consider the meat unsafe for human consumption.
The 2015 HAB affected the West Coast more than any other recorded bloom in history, costing an estimated $97 million dollars in damages to the Dungeness crab harvest alone. Just a few months ago, a HAB again sickened wildlife off the coast of Southern California.
Domoic acid manifests in all of the world’s upwelling zones—coastal regions where winds push away warm surface water and draw cold, nutrient-rich waters to the surface. The neurotoxin is poised to become even more prevalent as warming oceans disturb the balance of nutrients available.
For years, scientists have been working to understand the mechanisms behind these blooms. “We’ve long held a range of hypotheses in this field for what initiates blooms of this particular organism and its toxin production,” says Clarissa Anderson, one of Thukral’s collaborators and the director of the Southern California Coastal Ocean Observing System (SCCOOS). “We all want to know, What is that magic sauce?”
Now Allen’s interdisciplinary team has figured out a way to potentially anticipate future toxic events. The researchers’ methods center around monitoring the algae-infused waters for environmental DNA (eDNA), material that is minute in concentration but rich in genetic information. In a paper published last year in Proceedings of the National Academy of Science, they pulled out all the stops to harvest, isolate, and analyze the genes behind the algal havoc (DOI: 10.1073/pnas.2319177121).
The mechanics of a bloom
Fans of classic cinema may already know domoic acid. In 1961, Alfred Hitchcock found himself inspired by a startling newspaper report about a frenzy of disoriented seabirds terrifying residents of coastal Santa Cruz, California. The director wove elements of that incident into his film The Birds 2 years later. Since then, similar incidents in Monterey Bay have linked addled avians to a diet temporarily infused with domoic acid, a product of Monterey Bay’s occasional HABs.
When stressed, Pseudo-nitzschia may release domoic acid for a number of reasons, like to impede the growth of competing plankton or to stave off algae-grazing crustaceans. Also, domoic acid has been found to serve as an iron chelator. The element is critical to photosynthesis, so when it becomes scarce, Pseudo-nitzschia will release domoic acid extracellularly, where it can bind to iron in the environment and make it easier for the algae to absorb.
HABs have likely always occurred as part of natural ecological cycles, but modern blooms appear to be becoming more toxic. Anderson says that over the past 20–30 years, deeper waters from the equatorial Pacific have seen rising levels of nitrogen and decreasing levels of silicate. These waters, which came up through the California undercurrent, likely contributed to the size and intense toxicity of 2015’s bloom.
“This massive bloom exhausted silicate before nitrate,” explains John Ryan, a researcher at the Monterey Bay Aquarium Research Institute and coauthor of the paper. Each diatom needs silicate to build its tough cell walls, like a tiny suit of glassy armor. If they run out of silicate, the diatoms can’t divide, but the nitrogen-rich waters continue to fuel their metabolism.
Faced with a silicon shortage threatening their ability to reproduce and an accompanying shortage in essential iron, the nitrogen-charged Pseudo-nitzschia along the Pacific coastline in 2015 took drastic action. The algae started producing as much as 10–20 times their usual amount of iron-scavenging domoic acid. As the compound built up in the Pseudo-nitzschia, each morsel of algae that nearby crustaceans ate became “phenomenally toxic,” Ryan says.
In 2018, Thukral’s fellow researcher in Allen’s lab, Patrick Brunson, helped identify DabA, a key enzyme that kick-starts Pseudo-nitzschia’s biosynthesis of domoic acid (Science, DOI: 10.1126/science.aau0382). The paper “was a milestone study,” Allen says. It handed researchers a compass to seek out genes that, like dabA, express themselves as a Pseudo-nitzschia bloom takes shape. Now the team wanted to learn what was happening one step before that.
Thukral, Brunson, and the rest of the team figured that because cells express genes before translating them into proteins, they could try to detect genes that Pseudo-nitzschia activated around the same time or even before dabA. These could serve as biological alarm bells that a HAB event was imminent.
In the wake of that paper, Brunson found himself the beneficiary of scientific serendipity. Researchers at Moss Landing Marine Laboratories, 650 km up the US Pacific coast from his office at in San Diego, mentioned to Brunson’s team that they happened to have a year’s worth of plankton samples from 2015 sitting quietly in their freezers—including ones chock-full of Pseudo-nitzschia from the bloom.
These were exactly the kind of time-indexed samples that the team needed to take the next step in their research, moving from understanding what caused HABs on a genetic level to identifying the warning signs leading up to a HAB. Things could have gone differently, Allen says. Many discoveries never see the light of day: viable samples languish in freezers, or data gather dust as they wait for robust analysis that never comes, he says.
With the samples in hand, however, the researchers now faced a new challenge. From that slurry of biological material and miscellaneous sea gunk they needed to figure out how to extract and analyze the genetic data lying inside.
Unveiling genetics
The samples researchers netted during and leading up to the bloom—taken off a municipal wharf in nearby Monterey—provided a veritable goldmine of eDNA, genetic material that organisms shed into their surroundings. It has become an increasingly convenient and nonintrusive tool for researchers to get a picture of ecosystem dynamics.
For example, a 2024 study swabbed hawk beaks and talons for DNA and identified what species of animals the birds preyed upon. And in 2022, biogeochemists extracted the oldest DNA ever from river sediments and reconstructed an ecosystem that had existed in the area millions of years ago.
In addition to analyzing eDNA, Brunson and Thukral gleaned still more information using transcriptomics, a growing subfield of bioinformatics that catalogs the entirety of an organism’s RNA. By seeking out gene transcripts, such as ribosomal RNA, that differ between species, they could chart the evolution of the 2015 bloom—like how Pseudo-nitzschia australis had become the dominant diatom by April and had maintained its dominance into autumn.
Aware of the ocean conditions in the days leading up to the bloom—low iron and low silicon concentrations—Brunson and Thukral started to put together the puzzle pieces. Thukral’s efforts uncovered dabA’s molecular coconspirator: the gene sit1, which helps transport silicon compounds into Pseudo-nitzschia cells. She found that when silicon was at its scarcest in early summer 2015, expression of sit1 skyrocketed as the algal cells tried to eke more silicon out of the water to build their cell walls and divide.
Thukral figured out that when Pseudo-nitzschia express both genes at the same time—dabA when the algae are starting to synthesize domoic acid and sit1 as they struggle to divide themselves—it could serve as a “robust predictor” that the Pseudo-nitzschia are about to become a toxic powerhouse.
Sorting through and properly analyzing this treasure trove of genetic data—along with data on oceanographic conditions, community composition, and metabolomics—took the team years. “But it becomes pretty beautiful when you’re able to see patterns that are linking them together, and trying to crack the code as to what is taking place in the ocean that we can’t really see with our naked eye,” Thukral says. “All of this data allows us to chip away at that.”
A bit of notice
The team’s metabolomic investigations fell under the umbrella of a US National Oceanic and Atmospheric Administration (NOAA) research program dedicated to the ecology and oceanography of HABs. Their discoveries from plumbing the depths of environmental genetic data are a step toward something coveted by scientists and fisheries alike: the ability to predict blooms as much as a week before they erupt.
“It’s been exciting, because my field has always been prediction,” says SCCOOS’s Anderson, whose work has involved both remote sensing—such as monitoring HAB formation from space—and developing models that might help predict toxin formation. “But we’re always missing a lot of this fundamental knowledge. I’m really confident that now that we can do some of this molecular forecasting, that we’re a little closer towards a truly mechanistic understanding.”
Vera Trainer, the director of the University of Washington’s Olympic Region Harmful Algal Bloom program, who was not involved with Thukral’s study, will be happy for any help she can get. In the Pacific Northwest of the US, the current warning system has its shortcomings because it requires physically counting phytoplankton cells in water samples and measuring their toxin concentration. By the time high concentrations of toxin can be detected, however, a HAB may already be in progress. “If we had a week’s early warning using these genetic approaches, that would be great,” Trainer says.
She adds that toxic blooms also have an outsized impact on members of the Quinault Indian Nation, on the southwestern corner of Washington’s Olympic Peninsula, who have harvested razor clams for thousands of years. “How do you place a value on the loss of shellfish that you’ve been harvesting for centuries with your family?” Trainer asks. Genetic forecasting using eDNA could allow communities to harvest either before a bloom arrives or in unaffected locations.
“It’s an element ingrained into their lives,” Trainer says. “And when they cannot harvest, it’s damaging not just to their economic well-being, but their cultural well-being.”
Next steps
One of the relative weaknesses of the team’s data had nothing to do with their abilities. Their limitation lay in not having enough samples from the beating heart—the initiation sites—of the HABs.
“Where we really want to go next is more directed bloom sampling,” Brunson explains. For samples like those taken by the Moss Landing researchers at a local wharf, “you’re getting a unique environment that might not be precisely like the epicenter of the bloom.” As such, the gene expressions of the HAB that occurred on Moss Landing’s doorstep still need to be confirmed against those of other regions.
Brunson and Thukral’s fellow researchers back at the Monterey Bay Aquarium Research Institute have spent years developing new ocean technology that could provide these genetic samples with robotic precision. Their autonomous underwater vehicles (AUVs) can zoom forth into the ocean depths at a moment’s notice and vacuum up eDNA like an Atlantean Roomba.
Credit: MBARI/Monterey Bay Aquarium
The Monterey Bay Aquarium Research Institute’s autonomous underwater vehicles can prowl water bodies for signs of harmful algal blooms. They take water samples and even do onboard chemical analysis.
The AUV is outfitted with sensors that can continuously hunt for environmental markers so it can pilot itself into the thick of a HAB. This vehicle can then take “sips” of the surrounding water and store what it finds in one of dozens of filters. Researchers then have the choice to bring those samples ashore for hands-on analysis or have the AUV’s onboard systems get a quick look at their molecular components. Ryan says the AUV is “basically a laboratory in a can” that can lyse cells and analyze their contents using a light-based technique called surface plasmon resonance that can detect domoic acid.
“Once you prepare that vehicle with all the reagents inside, you need to wait for the right moment,” Ryan says. “Maybe it’s a mortality event: you see animals dying from domoic acid poisoning. You then remotely send your AUV on its mission to 1) map the phytoplankton distributions, and 2) report back real-time detection information.”
NOAA does, in fact, already have a fleet of ocean gliders monitoring the oceans, “but most of them aren’t out sniffing HABs,” Anderson explains.
SCCOOS has also stationed along the California coastline a fleet of a dozen robotic microscopes, dubbed Imaging FlowCytobots, that can photograph and identify each phytoplankton in 15 mL of water every hour.
Another set of approaches that could one day complement monitoring and data collection are prevention, control, and mitigation. In other words, scientists could use what they know to try to proactively intervene in natural processes to stop HABs from proliferating.
That line of thinking raises pragmatic and philosophical questions: Will advances in molecular forecasting lead to techniques that can circumvent HAB formation, and can the consequences of this sort of geoengineering be known?
Inside the hull of Monterey Bay Aquarium Research Institute’s autonomous underwater vehicles is an onboard system that can collect water the samples for hands-on testing in the lab or do surface plasmon resonance analysis on site.
“Once that horse has left the stable, it’s left the stable,” Anderson admits. In systems the size of the world’s oceans, preventive actions would require intervention on truly massive scales. “They’re much more effective in closed, freshwater systems, and there’s a ton of work being done in that field—with a lot of industry buy-in because they can make all kinds of chemicals that can effectively deal with this. But I do believe that [prevention, control, and mitigation] aspirations in the marine environment are a lot trickier.”
Going forward, however, the transcriptomic techniques that Brunson and Thukral used will also continue to bloom. The sheer amount of biological data circulating through the environment provides more material than could be analyzed by any one laboratory or in any one lifetime.
“That’s one of the amazing things about such a rich data set like this: there’s always so much to explore and learn,” Thukral says.
Jonathan Feakins is a freelance science and history writer based in Chicago. A version of this story first appeared in ACS Central Science: cenm.ag/algalblooms.
A five-year research project called Synthetic Human Genome (SynHG) has been launched in the UK, in which researchers plan to create large fragments of human DNA in the laboratory, The Guardian reports.
The goal of the research is to gain a deeper understanding of how the genome functions and lay the foundation for new treatments for complex diseases, including autoimmune diseases and viral organ damage.
The project is led by Professor Jason Chin from the Medical Research Council’s Laboratory of Molecular Biology (LMB) in Cambridge. The team also includes scientists from the universities of Cambridge, Kent, Manchester, Oxford and Imperial College London. The first stage involves the synthesis of individual sections of chromosomes, which the researchers will insert into human skin cells to observe their behaviour.
This is the first large-scale attempt to rewrite the human genome from the bottom up, from molecule to cell. Previous experience synthesizing the complete genome of E. coli has prepared Chin’s team for the human genome, which is almost a thousand times larger, at over 3 billion base pairs.
Researchers are paying particular attention to the so-called “dark matter of the genome” – sections of DNA whose function remains poorly understood. Their analysis may provide new answers about gene regulation, epigenetics, and the occurrence of hereditary diseases.
Working alongside the scientific team will be an ethics team, led by Professor Joy Zhang from the University of Kent, to examine the social implications and potential risks of the research, including concerns about the use of the technology to create “designer babies” or modified organisms for domestic or industrial purposes.
Bioethicists are also considering using synthetic mitochondria to prevent maternally transmitted diseases, a solution that could reduce the need for donors and simplify IVF procedures.
A new study by the Genomics and Microbial Evolution Group at the Miguel Hernández University of Elche (UMH) together with the Department of Host-Microbe Interactions at St. Jude Children’s Research Hospital in Memphis, USA, sheds light on one of the great enigmas of microbiology: why only certain strains of common bacteria become pandemic pathogens. The work, published in the prestigious journal Proceedings of the National Academy of Sciences (PNAS), focuses on Vibrio cholerae, the bacterium that causes cholera. It reveals that its most dangerous form arises from a specific combination of genes and allelic variants that give it an advantage in the human intestine. This research could pave the way for new strategies to predict and prevent future cholera outbreaks.
The study results from a collaboration between UMH researcher Mario López Pérez and Professor Salvador Almagro-Moreno of the St. Jude Children’s Research Hospital. It also involved UMH Professor José M. Haro Moreno and predoctoral researcher Alicia Campos López, affiliated with the Department of Plant Production and Microbiology.
Through an extensive analysis of over 1,840 Vibrio cholerae genomes, the researchers identified eleven distinct phylogenetic clusters, with the pandemic group belonging to the largest and located within a lineage shared with environmental strains. Their findings suggest that the emergence of pandemic strains, responsible for global cholera outbreaks, is largely dependent on the acquisition of unique modular gene clusters and allelic variations that confer a competitive advantage during intestinal colonization.. These act as nonlinear filters that prevent most environmental strains from becoming human pathogens.
As a result, only a small group of Vibrio cholerae strains can cause cholera in humans, despite the species’ vast natural diversity. We wondered why only this small subset has ever triggered pandemics.”
Mario López, UMH researcher, lead author of the study
The study reveals that the emergence of pandemic V. cholerae clones is constrained by specific genetic bottlenecks. These require: a genetic background pre-adapted for virulence, the acquisition of key gene clusters such as CTXΦ and VPI-1, their organization into specific modular arrangements, and finally, the presence of unique allelic variants. “Only when all these elements come together can a strain evolve into a pandemic-capable pathogen,” the researchers explain.
These features are absent in most environmental V. cholerae strains and appear to grant pandemic clones a key competitive advantage: enhanced ability to colonize the human gut.
“Interestingly, the genetic traits that enable V. cholerae to infect humans don’t benefit the bacteria in their natural aquatic environment,” López notes. In the wild, V. cholerae typically lives freely or in association with cyanobacteria colonies, mollusks, or crustaceans.
Cholera is endemic in parts of the world with poor water, sanitation, and hygiene infrastructure. Outbreaks can also occur after natural disasters that disrupt these systems. The disease is characterized by sudden, severe episodes of watery diarrhea, leading to rapid dehydration and, if untreated, potentially death.
“Our analytical model could be applied to other environmental bacteria to understand how pathogenic clones emerge from non-pathogenic populations,” López emphasizes. The study also opens the door to more precise surveillance of strains with pandemic potential-an approach that could be highly useful for future public health preparedness.
The research was supported by the U.S. National Science Foundation (NSF) through the CAREER program (#2045671) and by the Burroughs Wellcome Fund’s Investigator in the Pathogenesis of Infectious Disease program (#1021977). It also received funding from the Spanish “MICRO3GEN” project (PID2023-150293NB-I00), co-financed by the European Regional Development Fund (FEDER) and managed by the Spanish Ministry of Economy, Industry, and Competitiveness.
Source:
Miguel Hernández University of Elche (UMH)
Journal reference:
López-Pérez, M., et al. (2025). Allelic variations and gene cluster modularity act as nonlinear bottlenecks for cholera emergence. Proceedings of the National Academy of Sciences. doi.org/10.1073/pnas.2417915122.
Pictorial representation of the atmospheric layers of Mars. This purpose of this figure is to show the integrated nature of the planetary atmosphere and re-emphasizes the need to study these coupling processes. — astro-ph.SR
The study of the evolution of Martian atmosphere and its response to EUV irradiation is an extremely important topic in planetary science. One of the dominant effects of atmospheric losses is the photochemical escape of atomic oxygen from Mars.
Increasing the magnitude of the irradiation changes the response of the atmosphere. The purpose of the current paper is to analyze the effects of enhanced EUV irradiation on the escape rates of oxygen atoms.
We have used the solar flare of 2017 September 10 as the baseline flare intensity and varied the intensity of the flare from a factor of 3 up to 10 times the baseline flare. We see an increase in the escape flux by 40% for flares up to 5x the intensity of the baseline flare.
However, beyond this point, the increase in escape flux tapers off, reaching only about 17% above the baseline. At 10x the baseline flare intensity, the escape flux decreases by nearly 25% compared to the escape rate of the original flare. We also found that the total escape amount of hot O peaks at 7x the original flare intensity.
Additionally, we have studied the effects of the time scales over which the flare energy is delivered. We find that energy dissipative processes like radiative cooling and thermal collisions do not come into play instantaneously. The escape flux from higher intensity flares dominate initially, but as time progresses, energy dissipative processes have a significant effect on the escape rate.
Chirag Rathi, Dimitra Atri, Dattaraj B. Dhuri
Comments: 11 pages, 7 figures Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP) Cite as: arXiv:2506.20337 [astro-ph.SR] (or arXiv:2506.20337v1 [astro-ph.SR] for this version) https://doi.org/10.48550/arXiv.2506.20337 Focus to learn more Related DOI: https://doi.org/10.3847/PSJ/ade708 Focus to learn more Submission history From: Chirag Rathi [v1] Wed, 25 Jun 2025 11:48:01 UTC (1,141 KB) https://arxiv.org/abs/2506.20337 Astrobiology,
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For more than 20 years, NASA has relied on a network of spacecraft circling Mars to send data to and from the Red Planet. Without the constellation of five orbiters, the agency would not have been able to land its rovers on Mars or guide them through its terrain. Although the White House is keen on advancing human missions to the Martian surface, it also wants to get rid of that vital lifeline
The Mars Relay Network is a fleet of orbiters equipped with radio systems powered by the Sun to maintain regular contact with Earth. It’s an interconnected system that relays data between rovers and landers on the surface of Mars, transmitting it tens of millions of miles through space to radio antennas located on Earth. “Every image seen from the surface of Mars since 2004 has been transmitted through the Mars Relay Network,” according to NASA. The international orbital squad, which includes NASA’s Mars Odyssey, Mars Reconnaissance Orbiter, and MAVEN, and the European Space Agency’s Mars Express and ExoMars, would play a vital role in human missions to Mars. Three of them, however, are at risk of termination due to funding.
NASA is preparing for severe cuts under the White House’s proposed budget for 2026. The budget, released in May, highlights the administration’s “objectives of returning to the Moon before China and putting a man on Mars.” It also reduces NASA’s upcoming budget by $6 billion compared to 2025.
The impending cuts would significantly affect the budget for Mars-focused science missions, terminating funding for two of the NASA orbiters and one ESA spacecraft to recoup the cost of the network’s ongoing operations, Forbes reported. “We have not yet received direction from NASA HQ to stop work on these [Mars Relay] projects, and we wait for further instruction,” Roy Gladden, manager of the Mars Relay Network at NASA’s leading-edge Jet Propulsion Laboratory (JPL) in Pasadena, told Forbes.
Under the proposed budget, NASA’s planetary science budget would drop from $2.7 billion to $1.9 billion. On the other hand, the agency’s human space exploration budget received an additional $647 million compared to the 2025 budget. Judging by the allocation of funding, the administration is clearly failing to understand that ongoing science missions to Mars are crucial to achieving a human presence on the Red Planet.
The Mars Relay Network is part of NASA’s main infrastructure to communicate with Mars; decommissioning three of the orbiters would significantly reduce the network’s capacity. Given the complexity of the proposed first human missions to another planet, the communications network should be expanded to ensure precision and not the other way round.
It may be that the current administration would favor a commercial substitute to NASA’s Mars Relay Network. In late 2024, NASA revealed that it was studying proposals for communication networks to set up in Mars’ orbit, including a pitch by SpaceX for a Marslink constellation (similar to the company’s Starlink in Earth orbit). Either way, NASA would no doubt need to update its current Mars communications system to support human missions. It would make more sense, however, to give the agency more funding as it contemplates landing humans on another planet for the first time.
