Heating small patches of forest shows how climate warming might change the winner-loser dynamics as species struggle for control of prize territories. And such shifts in control could have wide-ranging effects on ecosystems.

The species are cavity-nesting ants in eastern North America. Normally, communities of these ant species go through frequent turnovers in control of nest sites. But as researchers heated enclosures to mimic increasingly severe climate warming, the control started shifting toward a few persistent winners. Several heat-loving species tended to stay in nests unusually long, instead of being replaced in faster ant upheavals, says Sarah Diamond of Case Western Reserve University in Cleveland.
That’s worrisome not only for the new perpetual losers among ants but for the ecosystem as a whole, she and her colleagues argue October 26 in Science Advances. Ants have an outsized effect on ecosystems. They churn up soil, shape the flow of nutrients and disperse seeds to new homes. Ant species that can’t compete in a warmer climate may blink out of the community array, with consequences for other species they affect.

Teasing out the indirect effects of climate change has been difficult. “We’ve all sort of thrown up our hands and said probably these interactions are quite important, but they’re really hard to measure so we’re just going to ignore that for now,” Diamond says.
Experiments have begun tackling those interactions, and the ant enclosures were among the most ambitious. At each of two experimental sites — in North Carolina and Massachusetts — researchers set up 15 roomy plots to mimic various warming scenarios, from 1.5 degrees Celsius above the surrounding air temperature to an extra 5.5 degrees C. To install outdoor heating, “we had backhoes in there digging trenches,” Diamond says. Giant propane tanks fueled boilers that forced warmer air into the enclosures to heat the soil. Computers monitored soil temperature and fine-tuned air flow.
At least 60 species of local ants came and went naturally, some of them nesting in boxes the researchers placed in the enclosures. For five years, the researchers regularly monitored which common species were living in the boxes.
Warmth gave an edge to a few heat-tolerant species such as Temnothorax longispinosus in the forest in Massachusetts. This tiny ant can build colonies inside an acorn and is a known target for attacks by slavemaker ants that invade nests instead of establishing their own. With increased warming, however, it and a few other heat-loving ants tended to hold their nests longer.

Those longer stints destabilize the ant community with its usual faster pace of turnovers of nests, which typically gives more species a chance at decent shelter and better luck in surviving in the community. What’s more, the analysis showed that the more a plot was heated, the more time the ants would need after some disturbance to return to the equilibrium of their usual affairs.

“A key strength of this study is their regular sampling,” says Jason Tylianakis, who holds joint appointments at the University of Canterbury in New Zealand and Imperial College London. Those data gave the scientists an unusually detailed picture of subtle community effects, he says.

The authors have “documented a new consequence of temperature change on communities,” says marine ecologist Sarah Gilman of the Claremont Colleges in California. Other studies have talked about climate change pushing communities to dramatically new, but ultimately stable states. But the ant experiment shows that climate change may be undermining the stability of communities that, at least for the moment, still look fairly normal.

NEW ORLEANS — Marijuana use is associated with an almost doubled risk of developing stress cardiomyopathy, a sudden life-threatening weakening of the heart muscle, according to a new study. Cannabis fans may find the results surprising, since two-thirds believe the drug has no lasting health effects. But as more states approve recreational use, scientists say there’s a renewed urgency to learn about the drug’s effects.

An estimated 22 million Americans — including 38 percent of college students — say they regularly use marijuana. Previous research has raised cardiovascular concerns: The drug has been linked to an increased risk of heart attack immediately after use, and a 2016 study in rodents found that one minute of exposure to marijuana smoke impairs the heart’s inner lining for 90 minutes, longer than tobacco’s effect.

The new study, presented November 13 during the American Heart Association’s Scientific Sessions, examined the occurrence of stress cardiomyopathy, which temporarily damages the tip of the heart. Researchers from St. Luke’s University Health Network in Bethlehem, Pa., searched a nationwide hospital database and found more than 33,000 admissions for stress cardiomyopathy from 2003 to 2011. Of those, 210 were identified as marijuana users, and had about twice the odds of developing the condition, said Amitoj Singh, who led the study. Young men were at highest risk and more likely to go into cardiac arrest despite having fewer cardiovascular risk factors. Notably, the number of marijuana-linked cardiomyopathies increased every year, from 17 in 2007 to 76 in 2011. “With recent legalization, I think that’s going to go up,” Singh said.

Enhancing just three genes helps plants harvest more light, raising new hopes for developing crops that can keep up with food demands from a crowded planet.

Genetically engineered tobacco plants, chosen to test the concept, managed the unusual feat of growing 14 to 20 percent more mass — meaning more crop yield — than untweaked plants, says Krishna Niyogi of the University of California, Berkeley and Lawrence Berkeley National Laboratory. The gains came from inserting different versions of three genes that control how quickly plants ramp back up to full energy-harvesting capacity after going into a protective mode to protect themselves from too-bright sunlight, researchers report in the Nov. 18 Science.
Among results published so far, “to my knowledge, this is the first example where crop growth has been enhanced by improving photosynthesis,” says plant physiologist John Evans at Australian National University in Canberra, who wasn’t part of the new project.

Photosynthesis, the basic green chemistry for converting the sun’s energy into food, isn’t a perfectly efficient process (SN: 2/20/16, p. 12). And the quest to improve efficiency by manipulating the interlocking steps of more than 100 reactions in living crops has been complex. “We can make things worse, but this is the first time we can make something better,” Evans says.

The underlying idea for the tobacco experiment came from an appreciation of how light and shade dance over leaves throughout the day in a farm field. Sudden blasts of intense sunlight are dangerous stuff; an overload can lead to chemical scorching in a plant’s light-catching chloroplasts. So when the sun’s movement or a toss from a breeze suddenly exposes a chloroplast to more sunlight than it can handle, a protection system kicks in.
Enzymes in the leaf create a surge of a paprika-colored molecule called zeaxanthin, which helps offload the excess energy as heat. This protection turns on within minutes, but turns off more slowly when the crisis is over, Niyogi says.
Restoring full photosynthesis takes a lot more than just enhancing the back-to-normal mechanisms. An enzyme called ZEP dismantles protective zeaxanthin when it’s no longer needed. But making the plant simply build more ZEP keeps the protective system from turning on properly in the first place — which could put a plant at risk. So researchers also enhanced the enzyme called VDE that builds the protective zeaxanthin. With those two enzymes in balance, a chloroplast can still rid itself of excess energy but get back to full operations faster.
Enhancing a third protein, PsbS, also helped, although researchers don’t yet understand the full details of how. Tobacco plants with modified versions of all three proteins grew bigger, as measured by the weight of dried plant material, than others.

The extra growth those genes produced “is a major, economically important gain,” says Maureen Hanson of Cornell University, who is working on a different approach to improving photosynthesis. Now, she says, the new paper’s idea is ready for attempted transfer to plants that people harvest for grains or fruits. Hanson is hopeful that size will increase there, too.

Coaxing plants to calm down faster after a crisis is just one strategy to make photosynthesis more efficient. Evans and Hanson are among those involved in efforts to improve a notoriously slow and distractible photosynthetic enzyme called Rubisco (SN Online: 9/19/14). Other researchers are trying to transfer a naturally more efficient photosynthetic system found in some tropical and subtropical plants, called C4 photosynthesis, into rice, one of the world’s main grains.

Older strategies for wringing more food from farms are not on track to keep up with soaring human population and food demands, Niyogi says. The United Nation’s Food and Agriculture Organization has estimated that feeding the world in 2050 could require boosting food production by an additional 70 percent. But the success of all of this, Niyogi notes, may depend on how people around the world feel about genetically engineered food.

Scanning a fetus’s genome just a few weeks after conception may soon be an option for expecting parents. Mom just needs to get a Pap smear first.

By scraping a woman’s cervix as early as five weeks into a pregnancy, researchers can collect enough fetal cells to test for abnormalities linked to more than 6,000 genetic disorders, researchers report November 2 in Science Translational Medicine. It’s not clear exactly how fetal cells make their way down to the cervix, says study coauthor Sascha Drewlo of Wayne State University School of Medicine in Detroit. But the cells may invade mom’s mucus-secreting glands, and then get washed into the cervical canal.

Current prenatal tests include amniocentesis and chorionic villus sampling, but they work later in pregnancy: at least 12 weeks for amnio and at least nine weeks for CVS. Amnio requires a long needle threaded through a pregnant woman’s belly and uterus; CVS often does, too. Instead, Drewlo’s team gathered fetal trophoblast cells, which give rise to the placenta, and were able to examine the genomes of 20 fetuses.

The new technique, which can work with as few as 125 fetal cells, could one day help physicians care for their tiniest patients. For some genetic conditions, such as congenital adrenal hyperplasia, early detection means mom can take some medicine to “actually treat the fetus in utero,” Drewlo says.

Nuts about Neandertals
Recent genetic analyses of populations around the world showed that a wave of ancient humans left Africa about 50,000 to 72,000 years ago. All non-Africans alive today originated from this single wave, Tina Hesman Saey reported in “One Africa exodus populated globe” (SN: 10/15/16, p. 6).

“If the Neandertals were already present when Homo sapiens arrived on the scene, from whence did the N­eandertals originate, and how did they get there ahead of the (true) humans?” Peter Goodwin asked.
“Neandertals didn’t race ahead of humans out of Africa,” Saey says. Some earlier ancestor of both modern humans and Neandertals migrated out of the continent long before either species came on the scene. “Neandertals evolved outside of Africa, possibly from Homo heidelbergensis. They ‘grew up’ in Europe and Southwest Asia and were already present when humans started to venture out of Africa” she says.

But once human ancestors ventured into new territories, they met up and mated with Neandertals and other hominids, Bruce Bower says. Scientists are studying physical changes in the bodies of various animal hybrids to understand signs of this ancient interbreeding, Bower reported in “The hybrid factor” (SN: 10/15/16, p. 22).

Online reader Mark S. wondered if hybridization could explain the similarities between even older hominids like Homo naledi and Australopithecus, which have collarbones and finger bones in common (SN: 5/14/16, p. 12).

Biological anthropologist Rebecca Ackermann of the University of Cape Town in South Africa suspects hybridization helped shape the a­natomy of H. naledi and other ancient hominid species, Bower says. But no DNA has been extracted from H. naledi fossils to explore that possibility. DNA from Spanish fo­ssils does suggest that Neandertals and Denisovans may have interbred more than 430,000 years ago (SN Online: 3/14/16).
Quantum leap through time
Researchers teleported quantum particles over long distances in Canada and China. The feats could lay the groundwork for a quantum internet, Emily Conover reported in “New steps toward quantum internet” (SN: 10/15/16, p. 13).

“Is there any chance that quantum communication could send messages to the past or future … information time travel?” online reader J Ferris asked.

“Unfortunately, quantum mechanics does not allow faster-than-light c­ommunication — although it seems like it could at first blush,” Conover says. Through entanglement, quantum particles appear to remotely affect one another instantaneously. But to transmit or receive actual information, other details about the me­asurement must be sent through normal light-speed channels. “That’s a good thing,” she says. “If faster-than-light communication were possible, communication back in time would be too, which would cause all kinds of weird paradoxes. You could talk to your parents before you were born and perhaps convince them not to have children.”

Failure to launch
A star that vanished in 2009 may be the first confirmed case of a failed supernova. A faint infrared light and a black hole are all that remain of NGC 6946, Christopher Crockett reported in “Lost star may be failed supernova” (SN: 10/15/16, p. 8).

Jan Steinman wondered if the star’s collapse released enough gravitational energy for scientists to detect it using the Advanced Laser Interferometer Gravitational-Wave Observatory, or LIGO, which confirmed the existence of gravitational waves earlier this year.

Failed supernovas indeed produce gravitational waves detectable by LIGO, Crockett says. However, the waves are generated at the heart of stellar explosions, regardless of whether or not those explosions “fail” and collapse into black holes. It would be difficult to tell the difference between a supernova and a failed one from the gravitational waves alone, says Fermilab’s James Annis.

For centuries, stargazers have known which star was Polaris and which was Sirius, but those designations were by unofficial tradition. The International Astronomical Union, arbiter of naming things in space, has now blessed the monikers of 227 stars in our galaxy. As of November 24, names such as Polaris (the North Star) and Betelgeuse (the bright red star in Orion) are approved.

Until now, there has been no central star registry or guidelines for naming. There are many star catalogs, each one designating stars with different combinations of letters and numbers. That excess of options has left most stars with an abundance of labels (HD 8890 is one of over 40 designations for Polaris).

The tangle of titles won’t disappear, but the new IAU catalog is a stab at formalizing the more popular names. Before this, only 14 stars (included in the 227) had been formally named, as part of the IAU’s contest to name notable exoplanets and the stars that they orbit (SN: 2/6/16, p. 5). One famous star is returning to its ancient roots. The brightest member of Alpha Centauri, the pair of stars that are among the closest to our solar system, is now officially dubbed Rigil Kentaurus, an early Arabic name meaning “foot of the centaur.”

In a golden chunk of 99-million-year-old amber, paleontologists have spotted something extraordinary: a tiny dinosaur tail with pristinely preserved feathers.

At a shade under 37 millimeters, about the length of a matchstick, the tail curves through the amber, eight full sections of vertebrae with mummified skin shrink-wrapped to bone. A full-bodied bush of long filaments sprouts along the tail’s length, researchers report December 8 in Current Biology.

It’s “an astonishing fossil,” writes study coauthor Lida Xing of the China University of Geosciences in Beijing and colleagues. Researchers have found Cretaceous feathers trapped in amber before, but the new find is the first with clearly identifiable bits of dinosaur included. The tail bones of the new fossil gave Xing’s team a clue to the dinosaur’s identity. It may have been a young coelurosaur that looked something like a miniature Tyrannosaurus rex.
Unlike dinosaur feathers pressed flat into rock, feathers in amber can offer more information about structure, the authors suggest. In amber, “the finest details of feathers are visible in three dimensions,” Xing and colleagues write.

The little dinosaur’s feathers lack a well-developed rachis, the narrow shaft that runs down the middle of some feathers, including those used by modern birds for flight. Instead, the dino’s feathers may have been ornamental, the authors say. Microscopy images suggest that the feathers were chestnut brown on top, and nearly white underneath.

SAN FRANCISCO — Earth’s innards are cooling off surprisingly fast.

The thickness of new volcanic crust forming on the seafloor has gotten thinner over the last 170 million years. That suggests that the underlying mantle is cooling about twice as fast as previously thought, researchers reported December 13 at the American Geophysical Union’s fall meeting.

The rapid mantle cooling offers fresh insight into how plate tectonics regulates Earth’s internal temperature, said study coauthor Harm Van Avendonk, a geophysicist at the University of Texas at Austin. “We’re seeing this kind of thin oceanic crust on the seafloor that may not have existed several hundred million years ago,” he said. “We always consider that the present is the clue to the past, but that doesn’t work here.”
The finding is fascinating, though the underlying data is sparse, said Laurent Montési, a geodynamicist at the University of Maryland in College Park. Measuring the thickness of seafloor crust requires seismic studies, and “you don’t have that everywhere; there’s nothing in the South Pacific, for example.” Still, he said, “it’s amazing that we can see the signature of the cooling of the Earth.” The finding could help explain why supercontinents such as Pangaea break apart, he added.

Earth’s mantle is made up of hot rock under high pressures. As material rises toward Earth’s surface, pressures drop and the rock starts melting. This molten material can spew onto the surface at mid-ocean ridges and construct new crust. When mantle temperatures are hotter, the melt zone is larger and the resulting crust is thicker. Near the upper boundary with the crust, mantle temperatures range from about 500° to 900° Celsius.

Comparing the thickness of oceanic crust of different ages, Van Avendonk and colleagues discovered that 170-million-year-old crust is 1.7 kilometers thicker on average than fresh crust. Chemical analyses of lava rocks suggest Earth’s mantle has cooled about 6 to 11 degrees on average every 100 million years over the last 2.5 billion years. But since the mid-Jurassic about 170 million years ago, the mantle has cooled around 15 to 20 degrees on average per 100 million years, the researchers estimate. While scientists expected the mantle to cool over time as heat left over from Earth’s formation and from radioactive decay dissipates, this degree of cooling was surprising.

Plate tectonics is causing this rapid cooldown, the researchers proposed. The sinking, shifting and formation of plates drive convection in the planet’s interior that shifts heat. This process also controls how fast different regions of the mantle cool. While mantle temperatures below the Pacific Ocean have decreased around 13 degrees per 100 million years, the mantle below the Atlantic and Indian oceans has cooled about 37 degrees per 100 million years.

The difference between the oceans is their distance to continents. The Atlantic and Indian oceans opened when the Pangaea supercontinent ripped apart. Before then, the underlying mantle was covered by continental crust, which served as an insulating blanket that kept mantle temperatures toasty, Van Avendonk proposed. As Pangaea split and the continents shifted, the mantle beneath the young oceans began cooling much faster. Over that same time period, the Pacific Ocean was largely isolated from the continents and cooled more gradually.
The insulating effect of the Pangaea supercontinent could help explain what drives Earth’s cycle of supercontinent formation and breakup, Montési said. Heat may build up underneath supercontinents, ultimately generating a massive rising plume of hot rock that splits the landmass apart. “This could explain why you get a breakup about 100 million years after you get a supercontinent assembled,” he said.

Imperfections in supersized diamonds are a bummer for gem cutters but a boon for geologists. Tiny metal shards embedded inside Earth’s biggest diamonds provide direct evidence that the planet’s rocky mantle contains metallic iron and nickel, scientists report in the Dec. 16 Science.

The presence of metal in the mantle is “something that’s been predicted in theory and experiments for a number of years, but this is the first time that we have samples that give us physical evidence,” says Evan Smith, a geologist at the Gemological Institute of America in New York City who led the study.
Understanding the composition of the mantle can help scientists figure out how it drives plate tectonics, and how elements like carbon and oxygen are cycled and stored in the Earth.

Diamonds form in the mantle when carbon-containing compounds are compressed and heated to great temperatures (SN: 4/30/16, p. 8). During this process, traces of other elements can sneak in as “inclusions.” Inclusions make the mineral less valuable as a gemstone, and chunks with many such imperfections are often rejected by jewelers. But to scientists, such stowaways are priceless: They provide some of the only physical evidence available of what’s going on deep inside Earth.
Smith and his colleagues used lasers to identify inclusions in samples from some of Earth’s largest diamonds. Some diamonds like these were originally hundreds or even thousands of carats. The Cullinan Diamond, for instance, was as big as two stacked decks of cards and weighed 621 grams, or more than a pound.
By analyzing the inclusions in 53 diamond samples, Smith’s team found that the megadiamonds formed much deeper than ordinary diamonds — hundreds of kilometers down, in a different part of the mantle.

“Not only are [these diamonds] very large and very valuable, but they appear to be very special in terms of their origin,” says Graham Pearson, a geochemist at the University of Alberta in Canada who wasn’t part of the study. Other minerals brought up from such a depth don’t preserve chemical clues to their environment in the same way.

In the deep diamonds, Smith found inclusions made of a mixture of solidified iron, nickel, carbon and sulfur, surrounded by a thin skin of methane and hydrogen.

Aside from the molten metal core, most iron inside Earth is thought to be incorporated into other minerals, not as a stand-alone metal, says Pearson.

But the metallic inclusions suggest that the part of the mantle where the large diamonds formed contains iron and nickel as metals. And the fact that the metals hadn’t reacted with other elements to form compounds suggests that the diamonds’ birthplace probably contains very little oxygen.

Smith thinks the metallic mixture was probably molten at the time the diamonds were forming. Instead of being sprinkled throughout like grated parmesan on spaghetti, ribbons of iron and nickel might have rippled through the mantle like gooey cheddar-jack through mac-and-cheese.

“You need very special conditions to get a metallic melt,” says Catherine McCammon, a geologist at the University of Bayreuth in Germany. So the idea that diamonds carry evidence of these conditions in the mantle is “pretty mind-blowing.”

Hollywood space flicks typically feature one type of hero: astronauts who defy the odds to soar into space and back again. But now a group of behind-the-scenes heroes from the early days of the U.S. space program are getting their due. Black female mathematicians performed essential calculations to safely send astronauts to and from Earth’s surface — in defiance of flagrant racism and sexism.

These “computers” — as they were known before the electronic computer came into widespread use — are the subject of Hidden Figures. The film focuses on three black women — Katherine Johnson (played by Taraji P. Henson), Dorothy Vaughan (Octavia Spencer) and Mary Jackson (Janelle Monáe) — and their work at NASA’s Langley Research Center in Hampton, Va., during the run-up to John Glenn’s orbit of the Earth in 1962.
A mathematics virtuoso, Katherine Johnson calculated or verified the flight trajectories for many of the nation’s space milestones. The film showcases her work on two: the first American in space (Alan Shepard), and the first American to orbit the Earth (John Glenn). But Johnson also had a hand in sending the first men to the moon, during the Apollo 11 mission, and when the Apollo 13 astronauts ran into trouble, Johnson worked on the calculations that helped them get home safely.

Mary Jackson worked on wind tunnel experiments at Langley, where she tested how spacecraft performed under high winds. The film follows Jackson as she overcomes obstacles of the Jim Crow era to become NASA’s first black female engineer. Though the movie focuses on her triumphant rise, after decades in that role, Jackson grew frustrated with the remaining glass ceilings and moved into an administrative role, helping women and minorities to advance their careers at NASA.
Johnson and Jackson got their start under the leadership of Dorothy Vaughan, who led the segregated group of “colored computers,” assigning black women to assist with calculations in various departments. As electronic computers became more essential Vaughan recognized their importance and became an expert programmer. A scene where she surreptitiously takes a book from whites-only section of a public library — a guide to the computing language FORTRAN — is a nod to Vaughan’s prowess with the language.
Electronic computers were so unfamiliar in the 1960s that everyone from engineers to astronauts felt more confident when a human computer calculated the numbers. After a room-sized IBM mainframe spits out figures for his trajectory, John Glenn requests, “Get the girl to check the numbers” — meaning Johnson. In the film, that request culminates in Johnson running a frantic last-minute check of the numbers and sprinting across the Langley campus while Glenn waits. In reality, that process took a day and a half.

For spaceflight fans, Hidden Figures provides an opportunity to be immersed in a neglected perspective. The women’s stories are uplifting, their resilience impressive and their retorts in response to those who underestimate them, witty.

But viewers should be aware that, although the main facts underpinning the plot are correct, liberties have been taken. Some of the NASA higher-ups in the film — including Johnson’s supervisor Al Harrison (Kevin Costner) — are not real people. And presumably because number crunching tends to be a bit thin in the suspense department, the filmmakers have dramatized some scenes — Johnson is pictured in Mission Control during Glenn’s flight, but in reality she watched it on television — which seems a shame because the contributions of these women don’t need to be exaggerated to sound momentous.