It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, September 15, 2026
Cryopreserved sperm could help safeguard the future of endangered pupfish
Using cryopreserved sperm alongside larger breeding populations in zoos and aquaria could dramatically improve the long-term survival prospects of endangered pupfish, according to new research.
Using cryopreserved sperm alongside larger breeding populations in zoos and aquaria could dramatically improve the long-term survival prospects of endangered pupfish, according to new research.
Scientists at Nottingham Trent University and Chester Zoo investigated 18 priority species of pupfish in zoos, finding that current population sizes were too small to maintain healthy levels of genetic diversity over the next century.
Pupfish are small freshwater fish, mostly found in North and Central America and the Caribbean. Many species live in isolated habitats in small numbers and are endangered due to factors such as habitat loss, water extraction, pollution and climate change.
“We found that current zoo populations of these pupfish are too small to remain genetically healthy over the next 100 years,” said lead author James Brereton, a PhD researcher in Nottingham Trent University’s School of Science and Technology and Scholar at Chester Zoo.
He said: “Without action, genetic diversity could decline very quickly. Increasing pupfish populations in collections and investing in cryopreservation and assisted reproductive technologies, could be crucial in protecting genetic diversity and improving the conservation prospects of these threatened species.”
Using population simulations, the team investigated whether stored, cryopreserved sperm could help preserve genetic diversity when introduced into future breeding programmes.
Their modelling showed that relying on existing zoo populations alone would require collections to expand substantially to meet the widely acknowledged target of retaining 90% of genetic diversity over 100 years.
Depending on the breeding scenario, this could require an average of between almost 1,600 and 9,500 fish across the priority species.
Introducing cryopreserved sperm into just ten percent of breeding attempts, however, could dramatically reduce the number of fish needed, their modelling suggested.
Under the most favourable scenario, just 150 individuals could be needed to maintain genetic diversity.
Genetic diversity is essential for species survival because it helps populations adapt to environmental change and reduces the risks associated with inbreeding.
The researchers say their findings suggest that combining cryopreservation with strategic breeding management could provide zoos with a practical way to strengthen the long-term viability of endangered fish populations while reducing the need for very large captive collections.
Dr Elena Hunter, the Director of Studies for the research in Nottingham Trent University’s Medical Technologies Innovation Facility, said: “This research showed that there are ways to preserve genetic diversity in species that require fewer animals in zoos by using a combination of natural breeding and cryopreserved sperm samples. Our research in pupfish priority species in zoos demonstrated the potential of such an approach.”
Dr Sue Walker, Head of Science at Chester Zoo, said: “The broader purpose of James’ work is to show that cryopreservation has a place in conservation, and this study clearly demonstrates that building cryopreservation into species conservation planning could improve outcomes for endangered populations.”
The study was also conducted in partnership with Dublin Zoo and the European Association of Zoos and Aquaria.
Tipping the Scales Using Cryopreservation: Modelling the Genetic Value and Management Potential of Integrated Cryopreservation for Threatened Ex-Situ Pupfish Populations
Light and nanomaterials could offer a new route for detecting metal contamination in water
Computer simulations identify a promising sensor architecture combining borosilicate glass, aluminum, aluminum oxide and graphene oxide to detect subtle optical changes associated with mercury, lead and zinc in water
Credit: Universidad Técnica Particular de Loja (UTPL)
Access to clean water depends not only on preventing pollution but also on being able to detect contaminants quickly and reliably. Among the pollutants of concern are metal ions such as mercury, lead and zinc, which can enter aquatic environments through industrial and other human activities.
Detecting these substances, particularly at low concentrations, often requires specialized analytical equipment and trained personnel. This has motivated scientists to investigate alternative sensing technologies that could eventually make water monitoring faster, simpler and more accessible.
A new study published in Electron explores one such possibility using an unusual combination of light, aluminum and graphene oxide. Researchers from institutions in Ecuador and Italy have computationally designed and optimized a multilayer optical sensor intended to respond to very small changes in the optical properties of water associated with Hg(II), Pb(II) and Zn(II), as well as selected mixtures containing two of these metal ions.
Importantly, the proposed sensor has not yet been fabricated or tested with real environmental water samples. The study represents a numerical design and optimization stage intended to establish which combination of materials could provide a promising basis for future experiments.
Turning an invisible change into an optical signal
The proposed technology is based on surface plasmon resonance, or SPR.
If that environment changes, the resonance angle changes as well. This means that a tiny variation occurring close to the sensor surface can be converted into a measurable change in light.
In the proposed sensor, the researchers modeled what would happen when aqueous environments corresponding to different metal-ion conditions altered the refractive index around the sensing surface. The simulations showed that these small optical changes produced measurable shifts in the predicted SPR resonance.
In simple terms, the approach seeks to translate an otherwise invisible change in the water into a change in the behavior of light.
Building the sensor one layer at a time
Rather than starting with a single material, the research team investigated how several thin layers could work together. The final simulated architecture contains four principal components: a borosilicate glass prism, a 60-nanometer aluminum film, a 32-nanometer aluminum oxide layer and a graphene oxide sensing layer.
Each component performs a different function. The borosilicate prism helps couple incoming light into the structure. It was selected after being compared computationally with other prism materials and provided a favorable balance between optical response and resonance sharpness under the conditions investigated.
Aluminum forms the plasmonic metallic layer. Gold is commonly associated with SPR sensing because of its chemical stability, but aluminum is abundant and comparatively inexpensive. The study therefore explored aluminum as a potentially lower-cost alternative.
Aluminum, however, oxidizes easily. The researchers consequently incorporated aluminum oxide, Al₂O₃, into the design. In the model, this layer serves both as a protective or passivating component and as an important part of the optical architecture. The final surface is coated with graphene oxide, a carbon-based nanomaterial containing oxygen-bearing chemical groups.
Why graphene oxide?
The scientists compared four carbon nanomaterials as possible sensing layers: graphene oxide, reduced graphene oxide, graphene and semiconducting single-walled carbon nanotubes.
Some of these materials generated larger shifts in resonance angle than graphene oxide. A larger shift alone, however, does not necessarily make a better sensor.
A useful optical signal must also remain sufficiently narrow and well defined to be measured precisely. The simulations showed that single-walled carbon nanotubes generated a particularly large angular response but also produced extreme broadening of the resonance. Reduced graphene oxide and graphene showed other compromises between signal displacement and resonance width. Graphene oxide provided the most balanced behavior among the nanomaterials evaluated: a measurable resonance shift combined with a comparatively narrow resonance.
This result illustrates an important principle in sensor design. The material producing the largest response is not automatically the best choice. A useful sensor requires a balance between how strongly the signal moves and how clearly that movement can be measured.
How does the sensor respond to different metal-ion conditions?
After optimizing the multilayer structure, the researchers modeled aqueous environments associated with Hg(II), Pb(II) and Zn(II), as well as two binary mixtures containing mercury.
Among the individual metal-ion conditions, Zn(II) produced the highest modeled angular sensitivity, while Hg(II) produced the lowest. Importantly, the two binary mixtures retained sensitivities above 333 °/RIU, indicating that the optical response of the simulated architecture remained strong under the mixed conditions evaluated.
This is relevant because environmental water does not necessarily contain only one dissolved species at a time. By including binary mixtures, the study moves beyond an idealized single-ion scenario and provides an initial computational basis for investigating more complex sensing environments.
However, these results should not be interpreted as evidence that the proposed sensor can already identify specific metal ions in real water samples. The simulations distinguish the modeled conditions through changes in refractive index. Experimental validation, interference studies and selective surface functionalization would still be required to demonstrate chemical selectivity in realistic water matrices.
What the sensor is actually measuring?
The computational model differentiates the investigated conditions through small changes in refractive index, an optical property describing how light propagates through a material.
The study does not establish that unmodified graphene oxide is intrinsically selective only for mercury, lead or zinc. In real water, many additional factors could influence the optical signal. These include sodium, calcium and magnesium ions, as well as pH, temperature, ionic strength and dissolved organic substances. Competitive interactions among different ions and the kinetics of their adsorption onto the sensing surface were also outside the scope of the current numerical model.
Future experimental versions of the sensor may therefore require selective surface functionalization — essentially adding chemical recognition elements that preferentially interact with particular target ions.
The simulations produced optical limits of detection on the order of 10⁻⁵ refractive-index units. This number should not be interpreted as a concentration in parts per million or parts per billion.
At this stage, it represents the smallest modeled change in refractive index that the optical system could theoretically resolve under the assumptions used in the calculations. Determining how that optical limit translates into actual concentrations of mercury, lead or zinc will require calibration with experimentally prepared samples.
From a virtual sensor to a real one
The researchers see the work as a starting point rather than a finished sensing device. Several challenges remain before the concept could become a practical tool.
Real thin films contain imperfections. Their surfaces may be rough, their thickness may vary slightly, and aluminum may continue to oxidize over time. Graphene oxide coatings may also be nonuniform. All of these factors could change the resonance observed experimentally.
Real water presents an additional challenge because it contains many substances not included in the current simulations. The next stages identified in the study therefore include fabrication-tolerance analysis, experimental production of the multilayer structure, selective surface functionalization, evaluation of long-term stability and testing with real water samples.
The authors also propose that future experimental systems could use conventional thin-film deposition for aluminum, controlled formation of the aluminum oxide layer and solution-based deposition of graphene oxide. Compact optical or microfluidic components could eventually be investigated as part of portable sensing formats.
For now, the study establishes the computational blueprint. Its central finding is that a relatively simple combination of borosilicate glass, aluminum, aluminum oxide and graphene oxide can, under modeled conditions, produce a sensitive optical response to small refractive-index variations associated with individual metal-ion environments and selected binary mixtures.
The work illustrates how nanomaterials, optics and computational modeling can be brought together to explore new approaches to environmental sensing — while also defining the experimental questions that must be answered before such a design can move from computer simulation to real-world water monitoring.
Simulation-Driven Optimization of a Borosilicate/Al/Al₂O₃/Graphene Multilayer SPR Sensor for Aqueous Detection of Metal Ions and Their Binary Mixtures
Study: Young military veterans have higher ‘forever chemical’ levels than non-veterans
A study led by Brown University researchers provides evidence that younger military veterans should consider getting screened for elevated PFAS levels and related health conditions.
PROVIDENCE, R.I. [Brown University] — Per- and polyfluoroalkyl substances (PFAS), often called forever chemicals because of their long-lasting presence in humans and the environment, are commonly found in consumer and industrial products. When Brown University researchers examined PFAS levels in the blood serum of United States military veterans, they found that younger veterans had higher PFAS concentrations and a higher prevalence of elevated PFAS compared with civilians of similar ages.
Because PFAS are associated with a range of health effects, including kidney and testicular cancers, liver and cardiovascular disease and thyroid dysfunction, the researchers said the findings can be helpful in guiding healthcare decisions for veterans.
“From a public health perspective, the critical thing about this work is that it comes with a recommendation,” said lead study author Christian Hoover, a pre-doctoral fellow in epidemiology at Brown’s School of Public Health. “If you’re a male veteran between the ages of 20 and 39, it would be advisable to speak to a physician about getting tested for PFAS levels. It’s also a good idea for people in this category to have a conversation about the health conditions associated with elevated PFAS levels, to see if screening for those conditions makes sense.”
The findings were published in Environmental Health Perspectives.
The researchers don’t know for sure what caused the elevated levels, but they said PFAS sources could include past exposure to firefighting foams, munitions and groundwater contamination.
The potential for elevated exposure in veterans was one of the reasons the researchers decided to investigate whether there was an association, said study author Joseph Braun, a professor of epidemiology at Brown. This is not something that had previously been explored, despite the fact that the National Health and Nutrition Examination Survey includes questions about military service.
The researchers analyzed eight survey cycles from 2003 to 2018, representing an estimated 22.8 million U.S. adults over age 20 with prior military service, after applying national survey weights. They found that younger veterans, aged 20 to 39, had greater PFAS concentrations (13% to 24% higher, depending on the specific chemical) than non-veterans of the same age.
The National Academies of Sciences, Engineering and Medicine recommend monitoring by a health care professional for individuals with PFAS levels above 20 ng/mL, given the potential for adverse health risks. The study found that young veterans were 18% more likely to exceed that threshold than young non-veterans.
The age of the veterans matters because younger veterans are more likely to have recent acute exposure to PFAS in the course of their work and training, Braun said.
“The common PFAS chemical PFOA, for example, has a half-life of about one and a half to two years, which means that if someone drank a jar of PFOA today, it would take 10 years for their body to get rid of it,” Braun said. “So as veterans get older and less actively involved with the military, they not only have less exposure, but the PFAS have time to be excreted out of the body.”
While younger veterans can get tested early and identify health risks before they become a health issue, Hoover noted that older veterans may still want to talk to their doctors.
“Even though our study wasn’t able to pick this up, it doesn’t mean that older veterans weren’t at the same risk when they were younger,” Hoover said.
Hoover added that the findings may inform Veterans Health Administration policies regarding coverage for PFAS testing.
Elizabeth Costello, a research scientist at Brown’s School of Public Health, contributed to the study, which was supported by grants from the National Institute of Environmental Health Sciences (F31ES036867, R01ES037335 and R21ES036946).
Singer’s blonde hair and red lipstick inspire scientists to name new group of yellow and red insects in her honor
A new genus of Australian bugs has been named Swiftiephylus in honor of Taylor Swift. The singer joins such luminaries as David Attenborough, Barak Obama and Beyoncé in the exclusive club of people to be immortalized in the scientific names of living things.
Swift lends her name to four insect species, newly classified from a zoological collection and described in research published in the De Gruyter Brill journal Insect Systematics and Evolution. The four insects together make up a new genus of Australian plant bug belonging to the family Miridae, the largest family of true bugs which has more than 11,000 described species worldwide.
Lead author Sarah Schroeder from the University of California, US, named one of the species Swiftiephylus taylorae directly after Swift, and chose S. amator, S. intrepidus and S. poetorum for the other three – names that draw on the singer’s albums Lover, Fearless and The Tortured Poets Department.
These Latin versions of 'Taylor', 'lover', 'fearless' and 'poets', conform to the formal scientific convention whereby a new species can be given any name by its finder, provided they use a two-part Latinized name governed by guidelines such as the International Code of Zoological Nomenclature.
Schroeder was inspired to name the insects after Swift as their pale yellow color and striking red markings reminded her of the singer’s characteristic blonde hair and red lipstick. The insects’ coloring mimics the flowers of the Australian she-oak, thus helping them evade predators.
“I didn’t know if I would ever have the opportunity to name a species again, so I wanted to do something both meaningful to science and authentic to me,” says Schroeder.
The specimens studied by Schroeder and co-author Professor Christiane Weirauch were collected in Australia between 1995 and 2004 as part of a National Science Foundation-funded biodiversity project ‘Planetary Biodiversity Inventory (PBI) for Plant Bugs’ that gathered more than 50,000 specimens. Since then, they have remained unstudied in various museum collections.
“I suppose we could say that revisiting these collections and describing hidden species makes them ‘vault species’, much like Taylor’s ‘vault tracks’ on her re-recordings,” Schroder says. “These hidden gems just hadn’t quite made it out into the world yet, and it took the right set of circumstances for them to be described.”
Natural history museums are an essential part of conservation science, and science as a whole, Schroeder adds, calling them "treasure troves of scientific discovery”.
There may be as many as 30 million insect species still undocumented. In that vast, largely unexplored world, a little star power may help some of its smallest inhabitants get noticed, studied and protected.
Credit: Photo by Songquia "Shawn" Wei, Michigan State University
Eighty years ago, a massive tsunami devastated parts of Hawaii, Alaska, Washington and Oregon following an earthquake off the coast of Alaska. A Michigan State University team is launching a project to study the underwater fault system where it originated – and whether it still poses a risk today.
Songqiao “Shawn” Wei, associate professor of earth and environmental sciences as well as computational mathematics, science and engineering, is gearing up for an expedition to measure vibrations of tectonic plates in the Alaskan-Aleutian subduction zone.
For this project, Wei’s team will place waterproof sensors called seismometers at the bottom of the Pacific Ocean near Alaska. They’ll use atomic clocks to accurately time each vibration they record. A battery will power the sensor for 15 months, at which point Wei’s team will collect them to analyze the data.
A project of this magnitude takes more money and planning than tracking vibrations on land. That’s where a National Science Foundation grant comes in.
MSU is partnering with the University of Hawaii in the first NSF award of its kind since January 2025. They’re also receiving ship time and instrument usage for the project.
Wei is studying this area because the 1946 tsunami was caused by a relatively small earthquake there. How this happened is still a mystery to seismologists.
While the sensors can’t tell researchers what happened 80 years ago, they can reveal how the fault is behaving today and help scientists assess whether the region could produce another earthquake or tsunami.
“We are still far from predicting earthquakes,” Wei said. “But we can improve our understanding of this local region, and that will be incorporated by the U.S. Geological Survey’s risk map and then into building codes.”
Tracking energy
Earthquakes happen when tectonic plates, which move along faults in the Earth’s lithosphere, get stuck against each other, building up pressure until they suddenly slip. This releases energy that shakes the ground.
Seismologists – researchers who study earthquakes – can use this energy to image the Earth’s interior. Tracking this data is critical for understanding why earthquakes happen, but collecting it is a matter of being in the right place at the right time.
That’s why Wei places seismometers in known earthquake hot spots like Samoa, Alaska and the Marianas and keeps them there for months or years.
Over time, the seismometers record every vibration so that Wei can analyze the data once the sensors are collected.
Faults on land are much easier to study. Typically, seismometers track vibrations for years, thanks to solar panels that keep their batteries charged. Scientists can also rely on global positioning systems, or GPS, for precise location and timing. Neither GPS nor solar power is available to instruments sitting deep underwater.
“Logistically, it’s very expensive and challenging to go to those places,” Wei said.
Before a ship ever leaves the harbor, Wei and his team map the ocean floor and find the best location for each seismometer, looking for a smooth, flat spot without rocks. Then, once it’s time to deploy, they use a floatation system to ensure the sensor drops slowly enough that it isn’t damaged by the fall. Just dropping one sensor can take hours.
The effort is necessary to understand tsunami risks. When an undersea earthquake suddenly raises or lowers the ocean floor, it displaces the water above it. That disturbance travels across the ocean as a tsunami, growing taller as it reaches shallow coastal waters.
Wei’s sensors will help the team understand how the Pacific and North American plates are interacting today and what that could mean for future earthquake risk.
New frontiers to discover
He’s also interested in a phenomenon called slow earthquakes. Over the past few decades, scientists have discovered that sometimes, fault movements unfold over days or weeks instead of a few seconds. This allows the plates to slowly release energy without the violent shaking of a typical earthquake.
Wei wants to know if slow earthquakes are related to the unusual 1946 earthquake and tsunami, and why they seem to be localized to this part of the Aleutian subduction zone.
The seismic data will also allow Wei to peer beneath the seafloor, much like a CAT scan uses waves to see inside the human body. He’s particularly interested in water trapped deep within the Earth and whether it changes the friction between tectonic plates, potentially influencing whether a rupture stops or grows into a major earthquake.
Wei’s team hopes they will launch their next research cruise in 2028, leaving the instruments on the ocean floor for about 15 months. What they record could help answer questions at the frontier of earthquake science: Why does one earthquake rupturing stop, while another keeps going? Why do some earthquakes slip slower, while others rupture quickly and violently?
Those questions can’t be answered in a lab simulation.
“For us, nature is the lab,” Wei said. “We need to go to those places. And it turns out Earth is always way more complicated than our human labs. There are always surprising discoveries.”
A dazzling sunset during a previous mission on the South Pacific from the deck of the U.S. Research Vessel Thomas G. Thompson.
