Textbooks May Be Wrong: Satellite Data Challenge the Two-Bulge Tide Model

By Science China Press, Aug. 17, 2026

https://scitechdaily.com/textbooks-may-be-wrong-satellite-data-challenge-the-two-bulge-tide-model/

A global analysis of satellite and tide-gauge measurements found that high and low tides often occurred where the familiar two-bulge model predicts the opposite. 

Credit: Shutterstock

Large-scale tidal observations challenge the textbook idea that two symmetric water bulges physically form on opposite sides of Earth.

For generations, students have learned to picture Earth’s oceans forming two broad bulges on opposite sides of the planet under the Moon’s gravitational influence. Researchers led by Yongfeng Yang of the Water Resources Comprehensive Development Center of Shandong Province, Jiajia Yuan of the School of Geomatics at Anhui University of Science and Technology, and Mingyuan Fan of the Water Resources Research Institute of Shandong Province have now tested whether those proposed bulges actually appear on Earth’s surface.

The question reaches back to the 18th century and concerns the double water bulge model, a familiar explanation of tides in physics, oceanography, and geography textbooks.

According to the classical model, the Moon’s gravity produces two symmetric water bulges on opposite sides of Earth. As Earth rotates, a location is expected to move through these raised regions and experience high tide, then through lower regions and experience low tide. Versions of this explanation also appear on websites maintained by institutions including NOAA, National Geographic, and NASA.

Satellite data challenge the bulge model

To test the prediction directly, the researchers analyzed tidal observations from 362,370 ocean locations measured by the Jason-3 satellite of AVISO throughout 2021. They compared occurrences of high and low tide with lunar angle, defined as the angle between a given location and the Moon relative to Earth’s center.

Among 175,402 locations falling within lunar angles of 0°–60° and 120°–180°, the regions where the model predicts water bulges, 56.84% experienced low tides and 43.16% experienced high tides. The opposite pattern appeared among 186,968 locations in the 60°–120° range, corresponding to the model’s depressed water region, where 56.38% experienced high tides.

(A1) Global pattern derived from satellite altimetry. 

(A2) Pacific Ocean pattern. 

(A3) Atlantic Ocean pattern. 

(B) Pattern derived from 166 tide-gauge stations. 

In the polar plot, the radial axis denotes the number of observed high- or low-tide events, and the radial sectors indicate the lunar angle in degrees.

 Credit: Science China Press

“The findings directly contradict the physical existence of two water bulges on the Earth’s surface,” the authors state. The researchers also examined observations from 166 tide-gauge stations during August 2014 and found the same overall pattern: low tides occurred predominantly at lunar angles of 0°–60° and 120°–180°, while high tides were more common between 60° and 120°.

Tide gauges show the same pattern

Researchers studying tides have long questioned whether two physical water bulges can actually form because real oceans are strongly affected by landmasses, the shape of ocean basins, the Coriolis force, and friction with the seafloor. According to the study authors, however, that skepticism had remained largely theoretical (oral), without direct observational evidence demonstrating the discrepancy.

The study also discusses a recently proposed alternative in which tides arise from oscillations of ocean basins rather than from seawater simply being pulled into two bulges. Under this view, the Moon’s gravity deforms the solid Earth, and as the elongated Earth rotates, ocean basins are repeatedly raised and lowered, driving water movement that produces daily cycles of high and low tides.

This “solid Earth deformation drives seawater to move” mechanism is consistent with the reported observations: low tides occur more often where the solid Earth rises upward (creating shallower water), while high tides occur more often where it is compressed (creating deeper water).

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A Molecule Found in Citrus Fruits Could Be a Secret Weapon to Rejuvenate The Liver

18 Aug. 2026, By P. Dockrill

https://www.sciencealert.com/a-molecule-found-in-citrus-fruits-could-be-a-secret-weapon-to-rejuvenate-the-liver

(Manu Vega/Moment/Getty Images)

The liver is one of the most remarkable organs in the human body.

This multitasking dynamo performs around 500 vital functions, including processing nutrients and filtering out harmful substances in our blood.

Despite the chemical toxins it has to contend with on a daily basis, the liver is preternaturally youthful, thanks to its unique ability to regenerate itself.

Even the trusty liver isn't immortal, though.

As the body starts to age, so too does the liver. And as it declines, it becomes susceptible to various forms of fatty liver disease.

But what if there were a way to help restore an aged liver to its youthful state?

In a new study published in npj Aging, scientists got a step closer to that very thing, using a compound found in citrus fruits to slow and even reverse signs of liver aging in mice.

Your liver, pictured at three years of age. (SciePro/Getty Images)

In an experiment, a team led by first author and molecular biologist Zhao-Qing Shen from National Yang Ming Chiao Tung University in Taiwan investigated hesperetin – a natural flavonoid found in lemons, limes, oranges, and other citruses – which has shown promise for a range of potential pharmacological effects, including various anti-inflammatory, anti-aging, and neuroprotective properties.

Hesperetin has previously been identified as an activator of a longevity-associated gene called CISD2 (or Cisd2 in mice), which is known to support liver and metabolic health.

"In the liver, Cisd2 deficiency promotes steatohepatitis [fatty liver disease] and hepatocellular carcinoma [liver cancer], whereas increased Cisd2 expression preserves youthful metabolic profiles and attenuates age-related hepatic dysfunction," the researchers explain in their paper.

"Notably, Cisd2 expression declines during aging, suggesting that restoring its expression may represent a promising strategy for delaying liver aging and preventing age-associated liver diseases."

To test their hypothesis, the researchers gave naturally old mice (21 months of age) a daily dose of hesperetin for five months, while a control group received an inactive substitute.

Mouse livers compared, showing young mice (three months of age, left), 

control mice (26 months, center),

 and hesperetin mice (26 months, right). 

(Shen et al., npj Aging, 2026)

At the end of the regimen, Cisd2 levels were significantly decreased in the livers of control animals (26 months old), but the old mice that had received daily hesperetin had liver Cisd2 levels comparable to those of young mice only three months old. Several other markers of liver aging and decline were also reduced, including fatty deposits, damaged liver cells, and inflammation.

"Collectively, these results demonstrate that hesperetin consumption alleviates hepatic pathological damage and delays liver aging in aged mice, an effect that closely correlates with the upregulation of Cisd2 expression," the researchers write.

An RNA sequencing analysis to compare gene activity showed the citrus compound had shifted gene expression in the treated animals towards a more youthful state, reversing a number of age-associated gene expression changes that were seen in the control animals.

A separate experiment showed that mice genetically engineered to lack Cisd2 in the main functional cells of their livers – which as a result already exhibited signs of poor liver health at just three months of age – did not respond to hesperetin treatment.

This supports the idea that in mouse liver cells, the citrus compound largely depends upon Cisd2 to work and is mostly ineffective in its absence, though the researchers also found some Cisd2-independent changes.

According to the researchers, hesperetin appears to work through a signaling pathway involving two different proteins, called Hmgcs2 and Pparα, which together increase Cisd2 activity.

While a lot more work will be needed to see whether hesperetin can safely produce similar effects to boost human liver health, the beginnings of the pathway might exist.

In the study, the research team analyzed non-tumor liver samples from 80 patients who had undergone surgery for liver cancer or benign tumors, and found that PPARα and CISD2 expression declined with age in the human liver tissues.

By itself, that doesn't prove anything, but it suggests that the reduced Cisd2 activity seen in mice might also be happening in older people. And if that's the case, maybe boosting that pathway with hesperetin could help rejuvenate human livers too.

Given everything the liver does for us, we owe it to the guy to find out.

"These findings taken together, provide strong evidence for hesperetin being a potent liver anti-aging treatment and form the groundwork for future clinical interventions using hesperetin as a potent Cisd2 activator and as a functional food derived from the peels of citrus fruits," the researchers write.

"Hesperetin from citrus peel and other sources has the ability potentially to slow down liver aging (or to rejuvenate an aging liver) as well as helping to ameliorate age-associated fatty liver disease."

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Review of Over 120 Trials Challenges The Advice to Always Finish Antibiotics

18 Aug. 2026, By J. Cockerill

https://www.sciencealert.com/always-finish-your-antibiotics-is-not-always-best-practice-surprised-youre-not-alone

This medical mantra may have been too successful. 

(Tanja Ivanova/Getty Images)

You've probably heard that taking a full course of antibiotics is essential for clearing bacterial infections and preventing antibiotic resistance.

That advice has been around ever since the discovery of penicillin in the 1940s.

But mounting evidence suggests that for certain common bacterial infections, shorter antibiotic durations may actually be a better approach.

There is no one-size-fits-all prescription for antibiotics; nuanced communication between patient and doctor is essential.

But a new study from public health experts in the United States, published in Open Forum Infectious Diseases, suggests that nuance is getting lost.

"Historically, there was very strong guidance by major health organizations and clinicians that you must always finish the course," says population health researcher Alistair Thorpe, of the University of Utah.

"Now, we're seeing a growing body of evidence saying that that is not always the case. And oftentimes, shorter durations of antibiotics are as effective and safe as longer alternatives."

But that information has been difficult to get across to patients, who have been hearing for decades that longer courses are required to stamp out bacterial infections, lest the microbes regain a foothold.

In recent decades, however, more than 120 randomized controlled trials have demonstrated that shorter courses of antibiotics for common infections can be just as effective, safer, and no more likely to promote antibiotic resistance than longer courses.

https://www.youtube.com/watch?v=pkTalaQsRlw

Antibiotic resistance is an urgent, global threat, with drug-resistant bacteria (aka 'superbugs') killing more than 1 million people each year.

Antibiotic use in agriculture has been flagged as a major issue, with contaminated wastewater carrying microbes downstream.

Superbugs also spread quickly in hospitals, and parched soils may be creating breeding grounds for drug-resistant microbes that can sail through the air.

But there's little evidence that failing to complete a prescribed course of antibiotics actually promotes antibiotic resistance.

Some experts even say that unnecessary exposure to antibiotics from excessively lengthy courses could be contributing to the problem.

In cases of pneumonia, for instance, shorter antibiotic courses appear effective in reducing infection recurrence and the spread of antibiotic resistance.

"Developing effective strategies for communicating updated guidance on antibiotic use requires understanding how patients' beliefs and preferences differ from current guidance," Thorpe and his colleagues write.

To better understand those beliefs and preferences, the researchers surveyed 1,475 US respondents, asking them: "Which antibiotic course length would you feel most comfortable taking for a bacterial respiratory infection (eg, pneumonia)?"

The majority of respondents (892) said they preferred a long course of 7 days or more to a short course of just 3-5 days.

"This preference was related to several factors, including having been told by a medical professional to 'always finish a course of antibiotics' and a general belief that longer treatments are inherently better," the researchers note.

"Although very few respondents (17.5 percent) had ever been told to stop taking antibiotics when they feel better, many (58.4 percent) said that they would be at least somewhat comfortable hearing it from their clinician."

That's an important point: stopping your antibiotics earlier than the doctor prescribes is risky business.

 This is a news article, not medical advice.

The takeaway here is to follow the treatment advised by your prescriber, even if it's shorter than you might have thought necessary.

But that doesn't mean you should make your own call on the duration.

Many serious bacterial infections do require longer courses of antibiotics: for example, tuberculosis and certain staph infections.

"Acknowledging uncertainty and the evolving nature of scientific evidence can foster trust, understanding, and acceptance of changes," the authors suggest.

"Framing updates to antibiotic use as routine scientific progress may help patients adapt to changes."

The good news is that more than 90 percent of respondents trusted their doctor's advice, which the authors say is an encouraging sign, given trends of declining trust in science and healthcare.

"Discuss with your clinician what the right duration is for you and when the right time is to stop your course," Thorpe says.

"Getting advice directly from a clinician on a one-to-one basis about what is most appropriate for you in that situation is the right way to go."

The Life of Earth

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Earth's Chemistry Did Something Strange Right Before Its Biggest Mass Extinctions

16 Aug. 2026, ByD. Robitzski

https://www.sciencealert.com/critical-transition-earths-chemistry-wobbled-during-its-5-biggest-mass-extinctions

(Anton Petrus/Moment/Getty Images)

Life on Earth, beginning with simple microorganisms that evolved and diversified into the incredible breadth of species living today, has always been turbulent.

Mass extinction events happen seemingly without warning, wiping out countless species and allowing others to take their place.

But it's not just disasters like supervolcanos and asteroid impacts that cause mass extinction.

New research suggests that around the time of five of the biggest mass extinction events on record, Earth's chemistry 'wobbled'.

In hindsight, a warning sign of the change to come.

The new study, published in Nature Communications, shows that Earth's climate occupied five distinct climate regimes separated by sharp transition periods of rapid environmental changes over the past 539 million years.

During these transition periods, the scientists found, life on Earth was particularly vulnerable to mass extinction, offering a new historical explanation for why some time periods were marked by such extreme loss of biodiversity.

Two ocean-chemistry signals (oxygen and carbon isotopes) tracked across 500 million years, with skull icons marking the 'Big 5' mass extinctions and orange highlights showing where the chemistry gave early warning signs of a coming shift.

  (Livina et al., Nature, 2026)

The research describes a metric for overall 'biosphere vulnerability' – combining rates of origination and extinction with standing biodiversity – indicating whether or not Earth is in a period where mass extinctions are more likely.

This measure for biotic stress "increases when we have increases in extinction rates and origination rates which also represent a drive to adapt to new and challenging conditions," study co-author Andrej Spiridonov, a paleontologist and Earth systems scientist at Vilnius University in Lithuania, told ScienceAlert.

"It also increases when diversity decreases, thus also reflecting the contraction of biotic possibilities. It should be noted that vulnerability is an ensemble metric, and when the biospheric state is vulnerable, it doesn't mean that every single species or even region of the world is 'stressed'."

It's not just disasters like supervolcanos and asteroid impacts that cause mass extinction.

 (Mark Garlick/Science Photo Library/Getty Images)



If you want to get into the math, the biosphere vulnerability index itself is a simple formula calculated from the natural logarithm of the total intensity of total turnover – the combined rates at which taxa originate and go extinct, relative to standardized standing diversity.

In short, it compares the rate of ecological change to the overall biodiversity to indicate whether or not an ecosystem is unstable and therefore vulnerable to even more drastic change.

Putting the index to the test, the researchers found that overall vulnerability varied across the five time periods they identified, each lasting 10 to more than 100 million years.

During these time periods – the researchers called them 'Haggis bins' because some of their graphs reminded them of the Scottish dish – heightened vulnerability to extinction and biodiversity loss largely correlated with increased temperatures.

Eras with higher temperatures, they found, tended to coincide with greater background biosphere vulnerability.

But biosphere vulnerability skyrocketed whenever one period was ending and another beginning – while the 'Big Five' mass extinctions were also associated with vulnerability peaks.

That doesn't mean that environmental turbulence causes mass extinction, Spiridonov said. For instance, we know that in some of these cases, another event like a massive asteroid impact was involved.

But it shows that these transitions can serve as a warning sign that life on Earth will temporarily be more fragile than normal, and more susceptible to another disaster coming along.

Vulnerability mapped against the 'Big 5' mass extinctions.

 (Livina et al., Nature, 2026)

"When the system approaches a critical transition," he said, that offers information "on possible future impending great change, such as a mass extinction or even a series of them."

What does that mean for today?

The study offers a historical analysis – it cannot predict what will happen to humanity or other species currently navigating an ongoing climate crisis and period of accelerated extinction.

"Our study suggests that the current geological era – the Cenozoic – is exceptionally stable having low vulnerability," he explained.

"It doesn't mean that the external impact by geophysical forces or the human impact wouldn't have any significant effects on the evolution of the biosphere. It just means, that under different background conditions, which prevailed in other geological eras, such a disturbance would have had much higher effect."

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Rewriting History: Researchers Uncover a Forgotten Amazon Civilization That May Have Housed 3 Million People

By U. of Helsinki, Aug. 16, 2026

https://scitechdaily.com/rewriting-history-researchers-uncover-a-forgotten-amazon-civilization-that-may-have-housed-3-million-people/

LiDAR image of the Fazenda Atlântica archaeological site in Acre, Brazil. 

Credit: M. Pärssinen and F. de Novaes

For nearly 1,500 years, the Aquiry civilization shaped southwestern Amazonia, and new research suggests it supported a much larger population than previously believed.

Beneath the dense forests of southwestern Amazonia, airborne lasers revealed a landscape covered with geometric earthworks, straight roads, and large ceremonial centers. The remains point to the Aquiry civilization, a multicultural society that occupied about 183,000 square kilometers between 600 BCE and 850 CE and may have supported millions of people.

Researchers examined a representative portion of this territory and documented more than 400 well-preserved examples of monumental ceremonial architecture, along with several sites from later settlements.

When the results were projected across the civilization’s entire range, the researchers produced a cautious estimate of more than 20,000 ancient ceremonial centers built from earth. The largest known complex extends across 50 hectares.

Millions may have lived there

Detailed archaeological surveys and radiocarbon dating indicate that between 1.25 million and 3 million people lived within Aquirian territory by the beginning of the first millennium.

That region represents less than 3 percent of Greater Amazonia. Its estimated population alone challenges earlier calculations placing the entire Amazon population between 1 million and 10 million people. The broader region may instead have supported tens of millions.

“Our findings overturn our understanding of the Amazon region’s past,” says Martti Pärssinen, emeritus professor at the University of Helsinki who led the study.

Plants shaped by human hands

The Aquiry transformed the surrounding forest as they built communities and produced food. They burned areas dominated by bamboo to create fields for maize, squash and manioc, as well as space for ceremonial centers and the broad roads connecting them.

They also cultivated gardens and actively managed useful tree species.

“The research shows that the human impact on the Amazon’s environment has been far greater than previously believed,” Pärssinen notes.

LiDAR image of the Fazenda Cipoal archaeological site in Acre, Brazil. 

Credit: University of Helsinki



Several nutrient-rich trees now common in the region reflect prolonged human management. These include Brazil nut trees, peach palms, which also produce edible palm hearts, and other fruit-bearing species.

By favoring trees with cultural and practical value, Aquiry communities helped some species spread while reducing the presence of others.

“This has direct implications for our understanding of the region’s biocultural history. The civilization also affected ancient Amazonia’s carbon production and carbon balance, which should be better accounted for in future climate models,” Pärssinen adds.

LiDAR reveals a hidden landscape

The investigation relied on airborne laser scanning known as LiDAR, a technology capable of mapping the shape of the land through thick vegetation. It exposed thousands of signs of ancient construction in rainforest areas that had received little previous study.

The flights scanned approximately 4,500 square kilometers. Researchers used more than half of that area for a systematic assessment of Aquiry earthworks.

“We flew long, roughly 450-kilometer straight transects, mapping a strip about one kilometer wide every ten kilometers. This allowed us to cover as large a continuous area as possible,” says Professor Juha Hyyppä of the Finnish Geospatial Research Institute (National Land Survey of Finland), who was responsible for the study’s technical execution.

Among the detected structures were large geometric formations and long, straight roads.

Aerial view of the Tequinho archaeological site in Acre, Brazil.

 Credit: University of Helsinki

“Their varying dimensions, shapes, construction methods, and locations reflect the distinct geographical and cultural characteristics of the region,” notes Risto Kalliola, emeritus professor at the University of Turku.

Indigenous oral traditions describe the centers as places where communities maintained relationships with one another and with other significant beings. They also hosted gatherings, political decisions and demonstrations of generosity by leaders.

Activities held there included ritual dancing, music, shared meals, athletic competitions and ball games.

A vast civilization remains mysterious

Much about the Aquiry civilization is still unknown. Its territory covered an area roughly comparable to modern Syria.

Because suitable stone is scarce in this part of Amazonia, the civilization left no stone ruins. Its monumental earthworks, now known as Amazonian geoglyphs, nevertheless show the enormous scale of construction.

The name Aquiry derives from an Indigenous name for the Acre River. “This was not a single realm but a network of many different communities,” notes Pirjo Kristiina Virtanen, professor of Indigenous studies at the University of Helsinki.

Researchers do not know which languages these communities spoke or what names they used for themselves.

The cause of the civilization’s apparently sudden decline around 850 CE also remains uncertain. The classic Maya civilization in Central America underwent a similarly abrupt collapse at roughly the same time.

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Scientists Solve a Vitamin B12 Mystery With an Unexpected Culprit

By Virginia Tech, Aug. 16, 2026

https://scitechdaily.com/scientists-solve-a-vitamin-b12-mystery-with-an-unexpected-culprit/

Researchers found that phage-driven bacterial rupture can provide enough vitamin B12 to support neighboring microbes.

 Credit: Stock

A virus kills a bacterium, and in the wreckage, other microbes may find one of life’s most essential nutrients: vitamin B12.

New research from Virginia Tech suggests that bacteriophages, viruses that infect bacteria, can release vitamin B12 trapped inside bacterial cells. That sudden nutrient windfall can then fuel neighboring microbes that cannot make B12 themselves, reshaping the wider community in the process.

Vitamin B12, also known as cobalamin, is required for critical biological processes, including DNA synthesis, red blood cell formation, and normal nerve function. Yet its origins are unusually exclusive. Humans, animals, and plants cannot manufacture it. Only certain bacteria and archaea have the machinery needed to produce it.

How Viruses Unlock Vitamin B12

Making B12 is also metabolically expensive, and only a minority of microorganisms can do it. Many others have evolved to obtain B12 or closely related compounds, called cobamides, from their surroundings instead. This dependence occurs across microbial ecosystems in the oceans, soil, and the mammalian gut.

That creates a biological puzzle. If B12 is costly to make and valuable to the cell producing it, why would enough of the vitamin end up outside those cells to sustain their neighbors?

The study, published in The ISME Journal, points to an unexpectedly violent answer.

Why B12 Stays Trapped in Bacteria

Bacteriophages, usually shortened to phages, infect bacteria. They are widespread wherever bacteria live and can strongly influence microbial communities, including those in the human gut.

During a lytic infection, a phage attaches to a bacterial cell and inserts its genetic material. The virus then hijacks the bacterium’s molecular machinery to manufacture new copies of itself. Eventually, the host cell ruptures.

The newly produced phages escape, but they are not the only things released. DNA, proteins, sugars, and other molecules that had been locked inside the bacterium spill into the surrounding environment.

“It has all the DNA, the protein, sugars, all these things that the bacterial cell normally hoards so that it can continue to grow,” Virginia Tech biologist Bryan Hsu said.

Bryan Hsu (at left) and David da Silva Barreira. The Hsu lab focuses on the gut microbiome.

 Credit: Felicia Spencer for Virginia Tech.

Phages Turn Bacteria Into Nutrient Sources

The researchers found that vitamin B12 can be part of that cellular bounty.

Hsu and his colleagues tested the idea using a controlled system containing a bacterium capable of producing B12 and another bacterium that needed the vitamin but could not make enough for itself.

When the B12 producer remained intact, the dependent bacterium failed to grow. The vitamin existed, but it was effectively locked away.

Once the researchers introduced a phage that destroyed the producer cells, the situation changed. B12 escaped into the environment at concentrations sufficient to support the other bacteria.

“In a genetically well-defined system, we can demonstrate that phage is necessary,” Hsu said. “The B12 doesn’t just leak out.”

Testing Whether B12 Drives Microbial Growth

A ruptured bacterium releases thousands of different cellular components, so the researchers needed to show that B12 itself was responsible for the growth.

David da Silva Barreira, the study’s first author and a former Virginia Tech postdoctoral associate, repeated the experiment using a genetically modified bacterial strain that could not produce B12.

Bryan Hsu. The Hsu lab focuses on the gut microbiome. 

Credit: Christina Franusich for Virginia Tech.



Phages still destroyed those bacteria, releasing their internal contents. But this time the B12-dependent microbes did not grow.

That result showed that simply bursting a bacterial cell was not enough. B12 was the critical resource supporting the neighboring microbes.

B12 Release Reshapes Gut Bacteria

The team then moved beyond the simplified laboratory pairing and tested major groups of bacteria associated with the human digestive tract. Once again, B12-dependent gut bacteria benefited when phages lysed B12-producing cells.

The effects extended beyond individual species. According to the study, phage-released B12 produced significant changes in the composition of bacterial communities and increased their diversity. When researchers simply added B12 directly to the growth medium, that diversity effect was reduced, suggesting that the timing and location of nutrient release may matter alongside the nutrient itself.

Phages are often described mainly in terms of the bacteria they kill. The new findings highlight another side of that relationship.

When a virus destroys one microbe, the contents of that cell do not disappear. They become resources that other organisms can potentially use. In that sense, phages may act as microscopic nutrient recyclers, transferring valuable molecules from organisms that manufacture them to organisms that depend on scavenging.

A Wider Role for Viruses in Microbial Ecosystems

The idea may extend well beyond the gut. Cobamides such as B12 are exchanged among organisms in environments ranging from soil to the ocean, and previous research has also found phage-mediated B12 release in marine microbial systems.

That gives viral infection an ecological role that is easy to overlook. A phage may kill its immediate bacterial host while indirectly helping unrelated microbes nearby.

For the gut microbiome, the findings suggest that viruses could influence the community not only by deciding which bacteria survive but also by changing who gets access to scarce nutrients.

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Saber-Toothed Cats Were A Diseased, Inbred Mess Before They Went Extinct, New Research Suggests

16 Aug. 2026, By I. Farkas

https://www.sciencealert.com/saber-toothed-cats-were-a-diseased-inbred-mess-before-they-went-extinct-new-research-suggests

Illustration depicting Smilodon fatalis.

 (Corey Ford/Stocktrek Images/Getty Images)

Whether waking up to a slobber-soaked ribbon draped across one's face or an unfortunately massacred mouse 'gifted' in one's slippers, anyone intimate with a cat can attest that their tiny tiger is evolutionarily built to hunt.

The domestic cat's distantly related predecessor, which split from the ancestors of tigers and modern cats 20 million years ago, was an exponentially more fearsome felid.

Weighing up to 600 pounds (270 kilograms), Smilodon fatalis was part 'cat,' part cruise missile: an ambush hunter with scimitar teeth.

In fact, its Greek-Latin name means something like "deadly knife-tooth," on account of the frightening murder-fangs fastened to its jaws.

A representation of S. fatalis at the Royal Tyrrell Museum, Drumheller, Alberta.

 (Chris Woodrich/Wikimedia Commons/CC BY-SA 4.0)



Yet in a recent study published in Frontiers in Veterinary Science, researchers found evidence that this powerful predator may have become inbred and developed spinal malformations before it exited the evolutionary stage at the end of the last Ice Age, circa 12,000 years ago.

The researchers used optical methods and computed tomography (CT) scans to examine more than 3,700 vertebrae – comprising at least 849 individual S. fatalis individuals – looking for signs of trauma, disease, and genetic defects.

These animals died and had their skeletal remnants preserved in the La Brea Tar Pits of Los Angeles, which may be the "world's richest ice age fossil site."

Such tar pits have become pop-media favorites, featured in iconic series like The Flintstones, The Simpsons, and a perhaps un-iconic 20th-century slapstick comedy starring former Beatles' drummer Ringo Starr as a 'caveman.'

Tar pits were also very deadly.

"The tar seeps were a carnivore trap," the researchers explain. "A large herbivore that became mired in the asphalt inadvertently would attract large carnivores and scavengers, which would themselves become entrapped in great numbers."

The S. fatalis vertebrae revealed diverse, sometimes severe pathologies, including many hints of chronic inflammatory disease. Additionally, they exhibited over 200 congenital vertebral malformations and nearly 50 fused vertebrae, as well as signs of abnormal bone growths and skeletal breakdown.

The researchers also identified lumbar vertebrae (from the lower back between the ribcage and pelvis) from three different individuals with signs of spinal nerve tumors (SNTs), which may result from genetic mutations.

Three may not sound like much.

But relative to the specimens examined in this work, the researchers estimate an SNT prevalence of 353 per 100,000 individuals. This is much higher than the upper-range estimates of incidence in humans, which is only 0.38 per 100,000 persons, the researchers note.

A Smilodon fatalis vertebra, showing signs of an enlarged cavity where a spinal nerve tumor may have grown (green arrow), as well as an illustration of its potential size.

  (Schmökel et al., Front. Vet. Sci., 2026)



The consequences of these congenital malformations could have been catastrophic for a population facing decline.

For comparison, most humans with SNTs report pain. In dogs, these tumors also often cause pain, along with muscle wasting and lameness, factors that would have significantly affected an ancient animal's hunting abilities.

Perhaps this is why we see so many hundreds of the Smilodon specimens in the tar pits.

An animal battling declines in function and disabilities may have licked its chops (and ditched some of its discretion) at the sight of a huge, juicy herbivore struggling to extricate itself from black, bubbling baths of tar.

Though well-supported by physical evidence, the inbreeding scenario may be impossible to prove without DNA analysis. And, unfortunately, "as is the case with all fossils from the LBTPM, no soft tissues are preserved," the researchers note.

Still, this presents worrying modern-day consequences as animal populations are under the multifold threats of climate change, environmental encroachment, and habitat loss.

"There is evidence that due to dramatically declining population numbers, there was an increasing occurrence of inbreeding in mammals at the end of the Pleistocene, with different health consequences," the researchers conclude, explaining that this issue was not exclusive to S. fatalis:

"DNA analysis of mammoths found in the permafrost revealed a high degree of inbreeding before they became extinct, potentially causing serious diseases such as diabetes mellitus and sensory deficits."

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Coffee Drinkers Show Surprising Differences in Fat, Muscle, and Hormones

By U. of Oulu, Finland. Aug. 16, 2026

https://scitechdaily.com/coffee-drinkers-show-surprising-differences-in-fat-muscle-and-hormones/

Coffee intake tracked with several biological signatures tied to metabolism and sex hormones, including patterns that varied by sex. 

Credit: Shutterstock

Habitual coffee consumption was associated with differences in body composition, metabolism, and sex hormones, but causation remains unproven.

A daily coffee habit has repeatedly been associated with lower risks of conditions including type 2 diabetes and cardiovascular disease, but exactly how coffee might relate to those health differences remains uncertain. Research from Finland now connects habitual coffee consumption with differences in body composition, metabolic markers, and sex hormones, with some of the strongest patterns varying between men and women.

Researchers at the University of Oulu analyzed information from 2,264 people aged 46 who participated in the Northern Finland Birth Cohort 1966. They examined whether regular coffee consumption was associated with metabolites circulating in the blood, cardiometabolic risk markers, and sex hormones.

Higher intake tracks leaner body composition

People who drank more coffee had less total body fat and visceral fat, along with greater skeletal muscle mass, even though their body mass index (BMI) was similar to that of participants who drank less coffee.

Higher coffee consumption was also associated with lower blood levels of branched-chain amino acids in both men and women. When persistently elevated, these biomarkers have previously been associated with insulin resistance and greater risk of type 2 diabetes.

Hormone patterns differ by sex

The clearest differences involving sex hormones appeared among men. Greater coffee consumption was associated with a more favorable glucose–insulin profile, higher total and bioavailable testosterone, and increased concentrations of sex hormone-binding globulin (SHBG). At the same time, free testosterone and the free androgen index were modestly lower. Among women, the hormonal associations were less extensive and primarily involved higher SHBG and lower measures of free androgens.

“Coffee is consumed by millions of people every day, yet we still know surprisingly little about how it relates to our metabolism and hormones. What stood out in our findings was a distinct hormonal signature that didn’t disappear even after we took into account BMI and lifestyle factors, with several of these associations differing between men and women,” says Luca Verroest, lead author of the study and Doctoral Researcher at the University of Oulu.

Associations do not establish cause

The findings raise the possibility that hormonal pathways contribute to the relationship between coffee consumption and metabolic health. However, because the research was observational, it can identify associations but cannot establish cause-and-effect relationships.

The question has particular relevance in Finland, where coffee consumption is among the highest in the world and averages about 11.8 kilograms per person each year.

Researchers are now working to determine whether coffee itself produces these biological differences and, if so, which compounds may be responsible. Those questions are being investigated in animal models, with the longer-term aim of moving toward human intervention studies. More evidence will be required before the findings can be used to shape dietary recommendations.

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Scientists Discover Hermit Crabs Doing a Job No One Expected

By Kobe U., Aug. 15, 2026

https://scitechdaily.com/scientists-discover-hermit-crabs-doing-a-job-no-one-expected/

Scientists have been wondering who disperses the seeds of Balanophoraceae, a family of parasitic plants growing in the shaded and windless understories of Japanese tropical forests. In his newest study, Kobe University botanist SUETSUGU Kenji provides “the first empirical evidence that hermit crabs can function as both external and internal seed dispersers.” Pictured above is Coenobita brevimanus scraping off the fruits of Balanophora fungosa. 

Credit: Suetgetsu Kenji

A parasitic plant on a Japanese island has found an unlikely way to send its offspring into the world. It appears to enlist wandering hermit crabs.

Hidden on the floor of coastal forests near Okinawa, Balanophora fungosa looks more like a fungus than a typical flowering plant. It has no green foliage to harvest sunlight. Instead, it survives by tapping into the roots of other plants for nutrients. When mature, it can produce as many as a million extremely small seeds, each contained inside a tiny, dry fruit. Members of the genus Balanophora produce some of the smallest fruits known among flowering plants.

For years, one basic question remained unresolved: Where do all those seeds go?

The obvious explanations were not especially convincing. “Many people assumed that they simply fall by gravity and are carried away by the wind, but the humid and windless forest floor makes this seem rather implausible,” says Kobe University botanist Kenji Suetsugu.
Hermit Crabs Reveal the Missing Link

The answer, reported in the journal Ecology, came from cameras placed in the forest. They recorded land hermit crabs, Coenobita brevimanus, using their pincers to scrape fruit from mature plants. The feeding could be intense. In some cases, a crab stripped nearly all of a plant’s fruit during a single night.

That behavior matters because the crabs do much more than eat.

Some of the fruits stick to a crab’s pincers, body, and shell as it feeds. Researchers later found fruit-carrying crabs several meters from the parent plants, showing that the animals can physically transport seeds across the forest floor. Observations in the study included crabs carrying fruits more than 5 meters (16 feet) from the plants.

Other seeds take a very different route.

Balanophora fungosa has dull colors, a yeasty scent, and easily detachable fruits, so Kobe University botanist SUETSUGU Kenji suspected the dispersers to be ants. But when he covered the plants with nets that let through ants but not larger animals, he found that the plant’s fruits were no longer picked up. 

Credit: Suetgetsu Kenji



Hermit Crabs Disperse Seeds Inside and Out

After the crabs swallow the fruit, some seeds pass through the digestive tract intact and remain viable afterward. That gives the plant a second potential transportation system. Land hermit crabs can move as far as 100 meters (328 feet), meaning a seed swallowed beside its parent could eventually be deposited much farther away.

Together, those two mechanisms make the discovery unusual. The crabs can act as external dispersers by carrying fruits on their bodies and as internal dispersers by consuming them and later passing viable seeds.

“This study provides the first empirical evidence that hermit crabs can function as both external and internal seed dispersers,” Suetsugu writes.

Two Surprising Ways Crabs Spread Seeds

For animals better known as scavengers, omnivores, and seed eaters, that is a surprising ecological role.

“I was excited to find this because these animals have usually been regarded as omnivores, scavengers, or seed predators rather than potential plant partners,” says Suetsugu.

Hermit crabs were not Suetsugu’s first suspects.

An Unexpected Ecological Partnership

His previous work had shown that other members of the Balanophoraceae family rely on small animals, including ants, crickets, and cockroaches, to move their fruits. Their muted colors and yeasty odors are very different from the bright, fleshy fruits commonly associated with birds and mammals.

Because B. fungosa produces fruits that detach easily, Suetsugu initially suspected ants.

He tested the idea by covering plants with mesh that ants could pass through but larger animals could not. If ants were doing the work, the fruits should still have disappeared.

They did not.
Cameras Expose the Real Seed Disperser

Once larger animals were excluded, fruit removal largely stopped. That result sent Suetsugu looking for a bigger visitor, and time-lapse cameras eventually revealed the hermit crabs.

But identifying the crabs raised another question: Were they simply taking advantage of an easy meal, or was there a more specific relationship at work?

A Yeasty Scent May Attract Hermit Crabs

Suetsugu observed the crabs around mature B. fungosa plants but not immature ones. Mature plants produce a yeasty odor, raising the possibility that the scent acts as a chemical advertisement to hungry animals moving across the forest floor.

For a plant living in a dark understory, smell may be particularly useful. Bright visual displays offer limited value close to the ground beneath a dense canopy, while an odor can travel through the surrounding air and alert animals to food they cannot yet see.

The crabs do not need to be specialized partners for the strategy to work. Their broad diets may actually make them useful. An omnivore searching constantly for edible material can encounter fruits, eat them, and then continue traveling, unintentionally carrying the plant’s next generation with it.

Small Invertebrates Could Shape Forests

Seed dispersal research has traditionally emphasized birds, mammals, and other vertebrates, but the new finding adds to evidence that small invertebrates can also shape where plants grow.

“When it comes to seed dispersal, large vertebrates have received most of the attention, but small-bodied invertebrates are often overlooked. Nevertheless, they may also help maintain seed movement, especially on islands, in fragmented habitats, and on shaded forest floors,” explains Suetsugu.

That could be especially important for plants such as B. fungosa. Its tiny seeds develop close to a humid, relatively still forest floor where wind offers little help. A mobile animal can cross obstacles and move seeds to places that gravity alone never could.

The discovery may also extend beyond a single plant and crab species. As Suetsugu notes, “Their abundance in coastal forests and omnivorous feeding habits suggest that this may represent a more general pattern.”

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We May Finally Know Why Mysterious Mushroom Fairy Rings Grow in Circles

15 Aug. 2026, By M. Starr

https://www.sciencealert.com/we-may-finally-know-why-mysterious-mushroom-fairy-rings-grow-in-circles

Many species of mushrooms mysteriously grow in rings. 

(VitaSerendipity/iStock/Getty Images Plus)

If you're ever in a patch of woods or meadow at just the right time of year, you may stumble across something that seems like an act of otherworldly trickery.

In the right circumstances, you might encounter an almost perfect ring of mushrooms, arrayed almost as though halted in a circle dance.

For centuries, these so-called fairy rings have inspired myth – some legends say they're the work of the devil, others of fairies, witches, or elves.

For all their ubiquity in folklore, though, it may surprise you to learn that scientists still don't know exactly why the fungus hidden beneath these mushrooms grows as a ring, rather than a solid disk, or why that ring radiates outward to form such neat circles.

Now, researchers led by mycologist Hanna Johannesson of Stockholm University in Sweden have peered under the grass, using DNA analysis and an unusual fungal transplantation experiment to look for answers.

What they have found – while preliminary – does not do much to dispel the fairy ring mythos. The results suggest that the fungi that form fairy rings may be trying to 'flee' something in their own wake.

"The results were most consistent with a transient-escape hypothesis," the researchers write in Royal Society Open Science, "and suggest that the mycelium avoids inhibitory factors present at the back edge of the mycelial growth front."

Marasmius oreades growing in a fairy ring. 

(JariJ/iStock/Getty Images Plus)



Fairy rings are not limited to a single species of mushroom. More than 100 different taxa have been observed forming them, but the basic principle is broadly similar.

Basically, the mushroom you see above ground is just a small part of a much larger organism. The mushroom is the fruiting body; the main body of the fungus is a branching network of thread-like structures, called mycelium, growing hidden in the darkness underneath.

As the fungus grows outward from its starting point, mushrooms can spring up along its advancing edge, tracing the subterranean growth in a circle. Over time, that circle can continue expanding.

Well, that's the general idea, anyway. But since the vast bulk of the fungus lives hidden in a complex ecosystem beneath our feet, the underground structure of a fairy ring has been surprisingly difficult to map.

To find out, the researchers investigated a species called Marasmius oreades – also known as the fairy ring mushroom or Scotch bonnet, growing in two separate fairy rings in a cemetery in Uppsala.

An overview of the soil samples obtained from each ring.

 (Olsson et al., R. Soc. Open Sci., 2026)



The researchers took soil samples along lines crossing each of the two rings, covering the mushroom-bare middle and the bristling-with-mushrooms edges of the circles, as well as the soil outside the circle, to serve as a background control.

Then, they sequenced the DNA they found therein, searching the resulting sequences for those that matched the M. oreades genome.

They found high concentrations of the mushroom's DNA in the soil from the circle rim – particularly the outer edge of the rim.

But in the middle of the circle, the DNA levels dropped to background levels similar to what was outside the circle – suggesting that not just the fruiting bodies, but the mycelium itself, assumes a ring-shaped architecture.

That's a pretty cool result, but it raised another question: Why, though?

The researchers identified several possibilities. Perhaps, once it gets going, the fungus simply continues in the same direction of travel at the same pace. Perhaps the ring's growth is oriented like a compass. Maybe the fungus even communicates with itself to tell all the sections how to form a ring.

Or maybe it's trying to get away from something.

Overview of the transplantation experiment. 

(Olsson et al., R. Soc. Open Sci., 2026)



To find out, the researchers dug up parts of each mushroom ring and either rotated or transplanted them in different spots. Then, they left the fungus alone to do its thing, coming back 14 months later to see what – if anything – had changed.

Their results were most consistent with what the researchers called the transient-escape hypothesis.

Under this scenario, the soil just behind the advancing front becomes temporarily unfavorable for growth. The fungus therefore keeps advancing into the soil ahead, away from the temporarily inhospitable conditions in its wake.

What the results couldn't tell the researchers was why. One reasonable explanation could be that the fungus temporarily depletes nutrients as it passes through and continues to move in the direction where the food is.

Another possibility is that it releases toxins that temporarily render the soil unattractive.

But whatever the explanation is, the effect doesn't last forever. Fungi planted back into the center of the circle were able to continue growing.

Meanwhile, a fungal section that was moved completely outside one ring continued in its previous direction, while the equivalent experiment on the second ring produced growth in an additional direction.

Further investigation will be needed to see if any of these ideas can be validated.

"Though additional studies with data from more rings, complemented with laboratory experiments, are needed to unveil the causal mechanism behind the observed patterns here, we show that it is possible to gain detailed information about fungal genomes directly from soil samples, which enables us to study vegetative growth of fungi in their natural environment," the researchers write.

"This will provide new insight and ignite new questions regarding the processes behind the fairy ring structure and growth pattern."

It would be remiss not to point out, though, that it's hard to make a portal to fairyland with a solid disk.

The Life of Earth

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Saving old trees may protect people's health more than planting new ones, study of Chicago neighborhoods finds

By O. Maule, Edited by N. Lanese, T. Ghose, Published Aug. 13, 2026

https://www.livescience.com/health/saving-old-trees-may-protect-peoples-health-more-than-planting-new-ones-study-of-chicago-neighborhoods-finds

Neighborhoods that lost canopy cover year over year saw mortality rates rise, while those that gained canopy saw death rates fall.

(Image credit: Robert Abbott Sengstacke via Getty Images)

Losing mature trees from a neighborhood may be a matter of life and death, a new study suggests.

The research, published Aug. 5 in the journal GeoHealth, tracked tree canopy cover and mortality across Chicago neighborhoods over 11 years. It found that it wasn't the number of trees in a neighborhood that was most strongly linked to residents' survival — it was whether the overall tree canopy was shrinking or growing from one year to the next.

Neighborhoods that kept losing tree cover tended to see death rates climb, especially in the hottest parts of the city, while neighborhoods that kept gaining canopy saw death rates fall.

The study can't say for certain that losing trees is what spiked death rates; it only shows the two trends moving together. But the finding adds to growing evidence that urban tree cover plays an outsized role in protecting people from extreme heat as the planet warms. Trees cool city blocks by shading pavement and buildings and releasing water vapor that lowers the surrounding air temperatures.

The new study's finding is less about discovering trees are good for people's health — scientists have suspected that for years — and more about how the researchers tracked it, said Vivek Shandas, a professor of urban studies and planning at Portland State University who wasn't involved in the work.

Much of the past work linking tree canopy to mortality relied on a single snapshot of a neighborhood's greenery, including a 2022 analysis of heat-related mortality tied to tree cover across dozens of U.S. cities. In this new study, researchers followed how canopy actually changed year to year, and it was that change rather than the raw number of trees that tracked with mortality.

The finding "reinforces what we've found in other cities," Shandas, who studies heat exposure and tree canopy loss in the U.S., told Live Science in an email. "Across 33 U.S. cities, nearly three-quarters were losing greenery, and the hottest neighborhoods were generally losing more — or gaining less — than cooler neighborhoods."

The effect size in the new study was notable: each year-over-year percentage-point increase in canopy was tied to roughly a 10% drop in mortality, with the greatest reductions in cardiovascular, respiratory and mental health-related deaths.

To reach their conclusion, the researchers combined annual satellite measurements of tree canopy for every Chicago census tract from 2011 through 2021 with more than 220,000 death records from state and city health departments. They built statistical models that controlled for factors like summer temperature, air pollution, income and residential segregation, which past studies show are tied to higher levels of mortality.

The team then grouped neighborhoods by their degree of canopy cover, and teased out how the heat and mortality data related to that metric. That helped them pinpoint where the effects of canopy loss or gain were strongest.

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