The Panamanian golden frog used to call the rainforests and cloud forests of its namesake country home, until a deadly fungus appeared. The loss of the frog and other amphibians may have contributed to a rise in malaria.
In the 1990s and 2000s, Costa Rica and Panama experienced spikes in malaria cases. The massive loss of amphibians in the region from a deadly fungal disease may have contributed to the uptick of this human disease.
The spread of the fungal disease chytridiomycosis was a slow-motion disaster, leading to a decades-long wave of amphibian declines globally. From the 1980s to the 2000s, the wave moved from northwest to southeast across Costa Rica and Panama, hitting different places at different times. An analysis of local ecological surveys, public health records and satellite data suggests a link between the amphibian die-offs and an increase in human malaria cases as the wave passed through, researchers report in the October Environmental Research Letters.
Headlines and summaries of the latest Science News articles, delivered to your inbox
Thank you for signing up!
There was a problem signing you up.
Teasing out ways that biodiversity loss “ripple[s] through ecosystems and affect[s] humans” can help make a case for preventive actions in the face of other ecological threats, says Michael Springborn, an environmental economist at the University of California, Davis.
On average, each county in Costa Rica and Panama had 0.8 to 1.1 additional cases of malaria per 1,000 people per year for about six years, beginning a couple of years after the amphibian losses, Springborn and colleagues found.
Other research suggests that amphibians serve as important checks on mosquito populations. Amphibian larvae eat mosquito larvae, and the animals compete with each other for resources, such as places to live.
So the missing frogs, toads and salamanders may have led to more mosquitoes and potentially more malaria transmission. But it’s unclear whether mosquito populations actually increased during this time, Springborn says, because those data don’t exist.
Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis or Bd, has led to the largest recorded loss of biodiversity due to a disease . It’s caused the decline of at least 500 species globally ( SN: 3/28/19 ). Ninety of those species are presumed extinct. Frogs and toads in the Americas and Australia have suffered the greatest declines. The international trade in amphibians has spread the fungus globally.
Springborn and colleagues wondered if the impacts of the amphibian losses stretched to humans too. The researchers turned to Costa Rica and Panama, where the fungus moved through ecosystems in a somewhat uniform way along the narrow strip of land on which the two countries sit, Springborn says. This meant that the researchers could work out when the fungus arrived at a given place. The team also looked at the number of malaria cases in those places before and after the amphibian die-offs.
In the first couple of years after the animals’ decline, malaria cases started to rise. For the following six years or so, cases remained elevated, then started to go down again. The researchers aren’t sure yet what was behind the eventual drop.
Studies on the connections between biodiversity loss and human health might “help motivate conservation by highlighting the direct benefits of conservation to human well-being,” says Hillary Young, a community ecologist at the University of California, Santa Barbara who was not involved in the work.
“Humans are causing wildlife to be lost at a rate similar to that of other major mass extinction events,” she says. “We are increasingly aware that these losses can have major impacts on human health and well-being — and, in particular, on risk of infectious disease.”
Aimee Cunningham is the biomedical writer. She has a master’s degree in science journalism from New York University.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
It don’t mean a thing if it ain’t got that swing — all you’ve got to do is stagger your timing.
For decades, fans of jazz music have debated why some songs have swing — the characteristic swaying feeling that compels feet to tap and heads to bop. Now, scientists may finally have an answer to Louis Armstrong’s classic song “What Is This Thing Called Swing?” and the secret lies in the timing of jazz soloists.
Headlines and summaries of the latest Science News articles, delivered to your inbox
Thank you for signing up!
There was a problem signing you up.
After listening to original and digitally tweaked piano recordings, jazz musicians were more than seven times as likely to rate music as “swinging” when the soloist’s timing was partially delayed with respect to the rhythm section, researchers report October 6 in Communications Physics.
In jazz, musicians are trained to swing eighth notes, or extend the duration of their downbeats — every other eighth note — and shorten the beats in between to create a galloping rhythm. But the technique on its own doesn’t explain swing, says physicist Theo Geisel. Computer-generated jazz songs with swung eighth notes still lack the style’s swaying feel ( SN: 2/17/22 ).
Past research hinted that swing might arise from differences in the timing between musicians within a band ( SN: 1/2/18 ). So Geisel and colleagues tweaked only the timing of the soloists in jazz recordings on a computer and asked professional and semiprofessional jazz musicians to rate each recording’s swing.
Musicians were nearly 7.5 times as likely to judge music as more swinging when the soloists’ downbeats were minutely delayed with respect to the rhythm section, but not their offbeats.
In a new study, jazz musicians rated the “swing” of these recordings of the song “Jordu” by Clifford Brown. The first recording is an unaltered version, and the second recording has been manipulated to increase the delay of the soloist’s downbeats by a very small amount. The musicians rated the tweaked recording as having more swing than the original.
Most of the musicians couldn’t put their finger on what was causing the effect, says Geisel, of the Max Planck Institute for Dynamics and Self-Organization in Göttingen, Germany. “Professional jazz musicians who have played for many years apparently have learned to do this unconsciously.”
The researchers also analyzed 456 jazz performances from various artists and found almost all soloists used downbeat delays, with an average delay of 30 milliseconds. This average held across the jazz subgenres of bebop, swing and hardbop, though there was some variation, Geisel says. “For faster tempos, the delays get smaller.”
Looking ahead, Geisel intends to investigate how “laid-back playing” — a popular style of delaying both downbeats and offbeats in jazz — influences swing.
Nikk Ogasa is a staff writer who focuses on the physical sciences for Science News . He has a master’s degree in geology from McGill University, and a master’s degree in science communication from the University of California, Santa Cruz.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Researchers used colorful dyes to illuminate the electrical charges of Bacillus subtilis spores, as seen here, to track how the bacteria responded to pulses of nutrients. Bacteria like these become dormant to survive tough environments, but it wasn’t previously known how they sense when to wake up.
Bacteria go to extremes to handle hard times: They hunker down, building a fortress-like shell around their DNA and turning off all signs of life. And yet, when times improve, these dormant spores can rise from the seeming dead.
But “you gotta be careful when you decide to come back to life,” says Peter Setlow, a biochemist at UConn Health in Farmington. “Because if you get it wrong, you die.” How is a spore to tell?
For spores of the bacterium Bacillus subtilis , the solution is simple: It counts.
These “living rocks” sense it’s time to revive, or germinate, by essentially counting how often they encounter nutrients, researchers report in a new study in the Oct. 7 Science .
Headlines and summaries of the latest Science News articles, delivered to your inbox
Thank you for signing up!
There was a problem signing you up.
“They appear to have literally no measurable biological activity,” says Gürol Süel, a microbiologist at the University of California, San Diego. But Süel and his colleagues knew that spores’ cores contain positively charged potassium atoms, and because these atoms can move around without the cell using energy, the team suspected that potassium could be involved in shocking the cells awake.
So the team exposed B. subtilis spores to nutrients and used colorful dyes to track the movement of potassium out of the core. With each exposure, more potassium left the core, shifting its electrical charge to be more negative. Once the spores’ cores were negatively charged enough, germination was triggered, like a champagne bottle finally popping its cork. The number of exposures it took to trigger germination varied by spore, just like some corks require more or less twisting to pop. Spores whose potassium movement was hamstrung showed limited change in electric charge and were less likely to “pop” back to life no matter how many nutrients they were exposed to, the team’s experiments showed.
Changes in the electrical charge of a cell are important across the tree of life, from determining when brain cells zip off messages to each other, to the snapping of a Venus flytrap ( SN: 10/14/20 ). Finding that spores also use electrical charges to set their wake-up calls excites Süel. “You want to find principles in biology,” he says, “processes that cross systems, that cross fields and boundaries.”
Spores are not only interesting for their unique and extreme biology, but also for practical applications. Some “can cause some rather nasty things” from food poisoning to anthrax, says Setlow, who was not involved in the study. Since spores are resistant to most antibiotics, understanding germination could lead to a way to bring them back to life in order to kill them for good.
Still, there are many unanswered questions about the “black box” of how spores start germination, like whether it’s possible for the spores to “reset” their potassium count. “We really are in the beginnings of trying to fill in that black box,” says Kaito Kikuchi, a biologist now at Reveal Biosciences in San Diego who conducted the work while at University of California, San Diego. But discovering how spores manage to track their environment while more dead than alive is an exciting start.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Giving revamped silkworm silk a metallic bath may make the strands both strong and stiff , scientists report October 6 in Matter . Some strands were up to 70 percent stronger than silk spun by spiders, the team found.
The work is the latest in a decades-long quest to create fibers as strong, lightweight and biodegradable as spider silk. If scientists could mass-produce such material, the potential uses range from the biomedical to the athletic. Sutures, artificial ligaments and tendons — even sporting equipment could get an arachnid enhancement.
Headlines and summaries of the latest Science News articles, delivered to your inbox
Thank you for signing up!
There was a problem signing you up.
“If you’ve got a climbing rope that weighs half of what it normally does and still has the same mechanical properties, then obviously you’re going to be a happy climber,” says Randy Lewis, a silk scientist at Utah State University in Logan who was not involved with the study.
Scrounging up enough silky material to make these super strong products has been a big hurdle. Silk from silkworms is simple to harvest, but not all that strong. And spider silk, the gold-standard for handspun strength and toughness, is not exactly easy to collect. “Unlike silkworms, spiders cannot be farmed due to their territorial and aggressive nature,” write study coauthor Zhi Lin, a structural biologist at Tianjin University in China, and colleagues.
Scientists around the world have tried to spin sturdy strands in the lab using silkworm cocoons as a starting point. The first step is to strip off the silk’s gummy outer coating. Scientists can do this by boiling the fibers in a chemical bath, but that can be like taking a hatchet to silk proteins. If the proteins get too damaged, it’s hard for scientists to respin them into high-quality strands, says Chris Holland, a materials scientist at the University of Sheffield in England who was not involved in the study.
Lin’s team tried gentler approaches, one of which used lower temperatures and a papaya enzyme, to help dissolve the silk’s coating. That mild-mannered method seemed to work. “They don’t have little itty-bitty pieces of silk protein,” Lewis says. “That’s huge because the bigger the proteins that remain, the stronger the fibers are going to be.”
After some processing steps, the researchers forced the resulting silk sludge through a tiny tube, like squeezing out toothpaste. Then, they bathed the extruded silk in a solution containing zinc and iron ions, eventually stretching the strands like taffy to make long, skinny fibers. The metal dip could be why some of the strands were so strong — Lin’s team detected zinc ions in the finished fibers. But Holland and Lewis aren’t so sure.
The team’s real innovation may be that “they’ve managed to unspin silk in a less damaging way,” Holland says. Lewis agrees. “In my mind,” he says, “that’s a major step forward.”
Meghan Rosen is a staff writer who reports on the life sciences for Science News . She earned a Ph.D. in biochemistry and molecular biology with an emphasis in biotechnology from the University of California, Davis, and later graduated from the science communication program at UC Santa Cruz.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Every 200 million years, the solar system passes through a spiral arm of the Milky Way (illustrated). Those encounters may have played a role in forming Earth’s first continental crust.
Previous theories have suggested that such impacts might have played a role in forming Earth’s landmasses. But there has been little research explaining how those impacts occurred, until now, the team says.
Headlines and summaries of the latest Science News articles, delivered to your inbox
Thank you for signing up!
There was a problem signing you up.
It’s an intriguing hypothesis, other scientists say, but it’s not the last word when it comes to explaining how Earth got its landmasses.
To peer back in time, geochronologist Chris Kirkland and his colleagues turned to geologic structures known as cratons ( SN: 12/3/10 ). These relics of Earth’s ancient continental crust are some of the planet’s oldest rocks. Using material from cratons in Australia and Greenland that are billions of years old, the team measured the chemistry of more than 2,000 bits of rock. The analysis let the researchers determine the exact ages of the rocks, and whether they had formed anew from molten material deep within the Earth or from earlier generations of existing crust.
When Kirkland and his colleagues looked for patterns in their measurements, the team found that new crust seemed to form in spurts at roughly regular intervals. “Every 200 million years, we see a pattern of more crust production,” says Kirkland, of Curtin University in Perth, Australia.
That timing rang a bell: It’s also the frequency at which the Earth passes through the spiral arms of the Milky Way ( SN: 12/30/15 ). The solar system loops around the center of the galaxy a bit faster than the spiral arms move, periodically passing through and overtaking them. Perhaps cosmic encounters with more stars, gas and dust within the spiral arms affected the young planet, the team suggests.
The idea makes sense, the researchers say, since the higher density of material in the spiral arms would have led to more gravitational tugs on the reservoir of comets at our solar system’s periphery ( SN: 8/18/22 ). Some of those encounters would have sent comets zooming into the inner solar system, and a fraction of those icy denizens would have collided with Earth, Kirkland and his team propose.
Earth was probably covered mostly by oceans billions of years ago, and the energy delivered by all those comets would have fractured the planet’s existing oceanic crust — the relatively dense rock present since even earlier in Earth’s history — and excavated copious amounts of material while launching shock waves into the planet. That mayhem would have primed the way for parts of Earth’s mantle to melt, Kirkland says. The resulting magma would have naturally separated into a denser part — the precursor to more oceanic crust — and a lighter, more buoyant liquid that eventually turned into continental crust, the researchers suggest.
That’s one hypothesis, but it’s far from a slam dunk, says Jesse Reimink, a geoscientist at Penn State who was not involved in the research. For starters, comet and meteorite impacts are notoriously tough to trace, especially that far back in time, he says. “There’s very few diagnostics of impacts.” And it’s not well-known whether such impacts, if they occurred in the first place, would have resulted in the release of magma, he says.
In the future, Kirkland and his colleagues hope to analyze moon rocks to look for the same pattern of crust formation ( SN: 7/15/19 ). Our nearest celestial neighbor would have been walloped by about the same amount of stuff that hit Earth, Kirkland says. “You’d predict it’d also be subject to these periodic impact events.”
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
In this illustration of a proton’s internal structure, quarks (represented by the letters U and D) are held together by the strong nuclear force (helices), which is imparted by particles called gluons.
Mark Garlick/Science Photo Library/Getty Images Plus
What holds the proton together — Science News , September 16, 1972
An experiment … at the CERN Laboratory in Geneva … gives an important clue to structural arrangements deep within the proton…. The result hints at the existence of a new and very strong fundamental interaction — the process that holds [quarks] together inside the protons.… A number of theorists have speculated about its nature and have even proposed an intermediate particle for it called a gluon.
Physicists finally found evidence for gluons in 1979, in the aftermath of electron-positron collisions at a German particle accelerator ( SN: 4/21/79, p. 262 ). Gluons bind quarks inside protons via the strong force — the most powerful force in nature. Recent investigations of gluons’ role inside the proton suggest the particles’ energy makes up about 36 percent of the proton’s mass ( SN: 12/22/18 & 1/5/19, p. 8 ). Future particle accelerators could gauge gluons’ contribution to the proton’s internal pressure , which averages a million trillion trillion times the strength of Earth’s atmospheric pressure ( SN: 6/9/18, p. 10 ).
Previously the staff writer for physical sciences at Science News , Maria Temming is the assistant editor at Science News Explores . She has bachelor’s degrees in physics and English, and a master’s in science writing.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
