As generative artificial intelligence technology moves further into education, the annual gaokao season, China's college entrance examination period, which will kick off on Sunday, is also seeing new changes.
For some students and teachers, AI may have begun to move beyond the role of a simple answer-finding tool. In certain study scenarios, it can be used to help students review mistakes, understand knowledge points, polish essays or receive revision suggestions. But this may also raise new questions for schools during the exam preparation period.
On Friday, the Ministry of Public Security's cyber police bureau said in a WeChat post that police in Yichun, Jiangxi Province, had handled a case in which a suspect used videos of so-called "gaokao exam paper bags" to claim he had access to "leaked 2026 gaokao questions and answers." The suspect allegedly attempted to sell the fake papers for 2,000 yuan ($281) each, and the account was shut down, according to the post.
China's Ministry of Education issued a warning on June 2, reminding students and parents to be alert to false advertising such as "famous teacher predicted exam questions" and "AI predicted exam questions," the China News Agency reported.
At the same time, several AI platforms in China have announced or indicated corresponding adjustments during the gaokao period to prevent the technology from being used for exam cheating, media reports said.
The discussion around AI and the gaokao has just begun.
AI use on campus
In daily exam preparation and classroom tutoring, some teachers and students in China have already begun exploring how AI technology can be used in practice.
In Shanghai, where educational resources are highly developed, frontline teachers are beginning to test the practical boundaries of AI in language teaching, while also seeing its limitations.
Wu Xinyi, an English teacher at a high school in Shanghai, told the Global Times that AI can be used to revise essays.
"I think it is acceptable to use AI to polish an essay. You can input a specific prompt, and it can make the language sound more advanced. In fact, some teachers now also use AI to assist with essay grading," Wu told the Global Times.
"Sometimes, we deliberately compare essays written by AI tools with those written by students. You can see that it does have some very good, even impressive parts, but many parts appear rigid and formulaic," she said.
Compared with discussions in more developed regions over AI-generated text, compliance and depth of thinking, the application of such technology in less-resourced grassroots schools faces more basic thresholds.
Xiao, a teacher at a county-level high school in East China's Shandong Province, told the Global Times that AI has been included in some teaching-related tasks, and relevant departments have been actively advocating its use. But in actual grassroots teaching, implementation remains difficult.
A document Xiao showed the Global Times about an AI competition organized by local education authorities suggested that local schools are being encouraged to explore AI-related teaching practices.
"Every step is a hard threshold, from improving teachers' understanding and changing their mindset to upgrading the school's overall hardware facilities, especially for rural county-level schools with limited resources like ours," Xiao said.
Meanwhile, overreliance on AI in relation to gaokao has also drawn warnings.
China's Ministry of Education issued a warning on June 2 for the 2026 gaokao, reminding students and parents to be alert to false advertising such as "famous teacher predicted exam questions" and "AI predicted exam questions," to take the exam with integrity and strictly observe legal boundaries, the Xinhua News Agency reported.
The ministry said gaokao questions have continued to undergo reform in recent years, with directions and exam content constantly changing and innovating. Relying on AI or "experts" to predict questions in order to obtain high scores is unrealistic, the ministry said.
Fairness in the exam room As AI is increasingly used in daily learning, how to prevent it from being used to cheat in a gaokao exam has become a matter of public concern.
Sichuan-based Red Star News recently reached out to several AI platforms in China. For instance, Doubao customer service said that Doubao could be used normally during the gaokao period, but photo-based question answering and similar functions would be unavailable, with specific arrangements subject to the actual page display during the exam.
A Tencent staff member said that, during last year's gaokao, Tencent's Yuanbao had made clear that it would not answer exam-related questions. An iFlytek staff member also said there was no definite information yet, but that large models would likely have their limits. Baidu's relevant business department said it had not yet received notice of restrictions on some Wenxin functions during the gaokao period, the report said.
According to a report by Xiaoxiang Morning Herald based in Central China's Hunan Province, in 2025, some users posted online that Tencent Yuanbao could not be used normally during the gaokao period.
After users sent image-recognition summary requests, Yuanbao replied that "this function is unavailable during gaokao hours." Other common AI tools such as Kimi, DeepSeek and Doubao also had related arrangements during the gaokao period.
The Ministry of Education reminded candidates that bringing a mobile phone, smart watch or bracelet, smart glasses and any other banned device into an exam room constitutes cheating, even if the device is switched off.
In April, the "AI + Education" action plan was issued by the Ministry of Education and other government departments, requiring in particular that AI applications be safe, trustworthy and controllable, the Beijing Youth Daily reported.
The report quoted Xie Yongjiang, director of the Institute of Internet Governance and Law at Beijing University of Posts and Telecommunications, as saying, "If there is even the smallest loophole in the organization of the exam, AI tools could magnify it infinitely and cause incalculable negative consequences. Restricting AI answering functions is meant to block the possibility of AI-assisted exam-taking and ensure absolute fairness in the exam."
From the perspective of international comparison and academic ethics, Estelle Qiu, a young scholar based in Australia, said AI is challenging intellectual property and human thinking while offering convenience.
Qiu told the Global Times that at the Australian university where she works, undergraduate students are allowed to use AI. In principle, the school allows them to first complete their own writing and then use AI for polishing, but students must clearly declare such use.
"However, there are two major pain points in AI use. First, it may undermine confidentiality to some extent. Second, when it comes to deeper academic papers, AI still cannot really get how the human mind works," she said.
The Beijing News said in a recent commentary that AI is evolving rapidly, with computing power and algorithms constantly improving and technological dividends being released. "But the faster it develops, the more necessary it is to respect rules and uphold bottom lines," the commentary said.
A viral stress-relief toy known as "Natasha" has sparked widespread controversy in China after videos showing users smashing, stomping on, piercing and otherwise "abusing" the baby-shaped toy spread across social media platforms.
According to the China Youth Daily, a growing number of primary and secondary schools across the country have issued notices banning the toy from campuses. As of Saturday, several major e-commerce platforms had removed promotional videos that marketed the product with violent content. However, some sellers were still using images of clenched fists and violence-oriented slogans to advertise the toy.
Sun Hongyan, a researcher at the China Youth & Children Research Center, a national institution specializing in youth and adolescent work research, warned that based on observational learning theory, children and adolescents could internalize behaviors by observing and imitating others. Violent ways of playing with the toy may be perceived by youth as entertaining and could normalize aggressive behaviors among young people, Sun said.
Sun noted that the toy's baby-like appearance amplifies its potential negative impact. Baby dolls symbolize vulnerable lives that deserve care and protection. As minors are still developing moral judgment, marketing messages such as "the harder you throw it, the more stress you relieve," combined with social media algorithms rewarding increasingly extreme content, may lead some young people to believe that bullying the weak is acceptable, gradually blurring their moral boundaries, according to Sun.
Yu Xukun, Executive Director of Beijing Children's Legal Aid and Research Center, also cautioned that repeated exposure to simulated violence in interaction with such toys could become psychological preparation for real-world aggression under certain circumstances.
"In cases we have handled, some children who suffered domestic violence came to believe that violence could solve problems and later directed such violence toward others, eventually facing legal consequences," Yu said.
Fang Zengquan, professor at School of Journalism and Communication at Beijing Normal University and director of the Center for Minors' Digital Literacy, criticized the marketing strategy behind the toy.
"Linking a baby-shaped toy directly to stress relief and promoting it with slogans such as 'Squeezing a baby is more stress-relieving than raising one' essentially turns the image of an infant into a gimmick," Fang said. "It encourages users, particularly adolescents, to derive pleasure from physically squeezing, pinching and deforming the toy, treating babies as objects for emotional release or entertainment."
Fang warned that repeatedly associating infant imagery with destructive behavior could weaken young people's empathy and protective instincts toward real babies and, in extreme cases, foster unconscious aggressive impulses toward living beings.
On June 1, the China Consumers Association (CCA) stated that violent and sexually suggestive marketing videos related to the toy may violate the law. According to the association, some sellers have posed the toy in sexually suggestive positions and paired it with ambiguous captions or adult-themed props, while others have used violent treatment of the toy to attract traffic and attention.
The CCA said such practices use vulgarity and violence as marketing gimmicks, run counter to core socialist values, violate the principles of common moral code, and can breach laws and regulations including the Cybersecurity Law and the Advertising Law.
The CCA urged businesses, platforms, schools and families not to allow "stress relief" to become a cover for violence or permit internet traffic to reward vulgar content.
Stress-relief toys are fundamentally products for emotional and self-oriented consumption, the CCA said, adding that all parties should work together to foster healthy and sustainable emotional-consumption environments. Online platforms should fulfill their gatekeeping responsibilities by removing and banning content involving violence, pornography and other materials that violate public morality. Manufacturers and sellers should abide by laws and regulations, ensure their products are both entertaining and safe. Meanwhile, families and schools should help minors develop healthy ways to manage stress and identify harmful online content.
The waters slated for "delimitation" by Japan and the Philippines lie east of China's Taiwan island. Their proposed so-called "delimitation negotiations" gravely infringe on China's maritime rights and interests, run counter to international law and the basic norms governing international relations, and are entirely illegal, null and void, Zhu Fenglian, a spokesperson for the State Council Taiwan Affairs Office said on Wednesday.
Zhu noted that compatriots across the Taiwan Straits belong to the Chinese nation. They must uphold their national stance, stand for the fundamental interests of the nation, and jointly safeguard China's sovereignty and territorial integrity as well as the overall interests of the Chinese nation.
Should the DPP authorities collude with external forces to betray national interests, they will surely be spurned by compatriots on both sides of the Straits and punished by history, the spokesperson said.
64 Chinese nationals who had been detained by Philippine authorities were released on Thursday evening, with embassy staff dispatched to the scene to provide assistance and care, the Chinese Embassy in the Philippines announced in a statement on Friday. Another six Chinese nationals are currently undergoing procedures for their release.
These Chinese nationals had been working at a steel plant in Misamis Oriental Province of the Philippines and were detained by Philippine law enforcement authorities on May 15.
According to the Chinese Embassy, the Philippine Department of Justice recently ruled that evidence was insufficient to support allegations that the Chinese nationals had violated the country's nuclear safety law, immigration regulations and labor laws, and therefore ordered their release.
The Chinese Embassy and consulates in the Philippines attached great importance to the case and repeatedly lodged solemn representations with senior Philippine officials and relevant government agencies, urging the Philippine side to handle the matter in a lawful, fair and expeditious manner and to refrain from infringing upon the legitimate rights and interests of Chinese citizens, according to the statement by the Chinese Embassy.
During the detention period, Chinese diplomatic missions in the Philippines conducted multiple consular visits to the detained nationals and continued to provide them with assistance and support. The embassy said it will continue to make every effort to safeguard the safety, lawful rights and interests of Chinese citizens and institutions in the Philippines, while once again reminding Chinese nationals in the country to strictly comply with local laws and regulations.
On Wednesday, Chinese Embassy spokesperson Ji Lingpeng expressed China's position regarding the frequent detention of Chinese citizens by Philippine law enforcement agencies in recent months.
Ji said China highly values the protection of the personal safety and legitimate rights and interests of Chinese citizens in the Philippines and has serious concerns over the recent actions taken by Philippine military and law enforcement authorities against Chinese nationals.
For every case involving detained Chinese citizens, Chinese diplomatic missions in the Philippines have lodged immediate representations with the Philippine side, urging authorities to notify Chinese diplomatic and consular missions within four days of any detention, arrest or other deprivation of liberty involving Chinese citizens and to clearly explain the reasons for such actions, Ji said.
He also called on the Philippine side to handle relevant cases in accordance with the law, ensure the personal safety, lawful rights, humanitarian treatment and due process rights of the individuals concerned, and promptly release those found not to have violated Philippine laws, rather than subjecting them to unlawful or prolonged detention.
To quickly unfurl and refold their wings, earwigs stretch the rules of origami.
Yes, those garden pests that scurry out from under overturned flowerpots can also fly. Because earwigs spend most of their time underground and only occasionally take to the air, they pack their wings into packages with a surface area more than 10 times smaller than when unfurled, using an origami-like series of folds. Springy wing joints let the insects bypass some of the mathematical constraints that normally limit the way a rigid two-dimensional material can be folded, researchers report March 23 in Science. Earwig wings’ folding pattern should be impossible according to mathematical equations that predict the three-dimensional designs that can be made by folding a two-dimensional material like a sheet of paper, says study coauthor Andres Arrieta, a mechanical engineer at Purdue University in West Lafayette, Ind.
Origami theory assumes that the material being folded is perfectly rigid. But the joints of earwigs’ wings — where creases form — are rich in a rubbery polymer called resilin. This little bit of stretch lets earwig wings do what a regular origami structure can’t: lock into two different conformations, open or folded up, and transition between the two. It’s an example of a bistable structure — something like the slap bracelets, popular in the 1980s and 1990s, which switch from a flat conformation to a curved one when whacked against a wrist, says study coauthor André Studart, a materials scientist at ETH Zürich. When locked open, earwig wings store energy in the springy resilin joints. When that strain is released, the wings rapidly crumple back to their folded position. Such constructions can inform robotics design. Inspired by the wings, the researchers created a prototype gripper. Its rigid pieces are held together by rubbery, strategically placed joints. Within fractions of a second, the structure can snap from its mostly flat conformation to one that can grip a small object and hold it without constant external force. While other materials scientists have pushed the limits of origami by making flat pieces bendable, this design instead stretches the hinges, says Jesse Silverberg, a physicist at Harvard University who wasn’t part of the study. Such a design has been observed and discussed, but never before been implemented in this way.
The earwig “is a beautiful example of how nature uses slight extensions to ideal mathematical origami to do something amazing,” says Itai Cohen, a physicist at Cornell University who wasn’t part of the study.
Perhaps that’s a slight redemption for the much-maligned insect.
The Chugach people of southern Alaska’s Kenai Peninsula have picked berries for generations. Tart blueberries and sweet, raspberry-like salmonberries — an Alaska favorite — are baked into pies and boiled into jams. But in the summer of 2009, the bushes stayed brown and the berries never came.
For three more years, harvests failed. “It hit the communities very hard,” says Nathan Lojewski, the forestry manager for Chugachmiut, a nonprofit tribal consortium for seven villages in the Chugach region. The berry bushes had been ravaged by caterpillars of geometrid moths — the Bruce spanworm (Operophtera bruceata) and the autumnal moth (Epirrita autumnata). The insects had laid their eggs in the fall, and as soon as the leaf buds began growing in the spring, the eggs hatched and the inchworms nibbled the stalks bare.
Chugach elders had no traditional knowledge of an outbreak on this scale in the region, even though the insects were known in Alaska. “These berries were incredibly important. There would have been a story, something in the oral history,” Lojewski says. “As far as the tribe was concerned, this had not happened before.”
At the peak of the multiyear outbreak, the caterpillars climbed from the berry bushes into trees. The pests munched through foliage from Port Graham, at the tip of the Kenai Peninsula, to Wasilla, north of Anchorage, about 300 kilometers away. In summer, thick brown-gray layers of denuded willows, alders and birches lined the mountainsides above stretches of Sitka spruce. Two summers ago, almost a decade after the first infestation, the moths returned. “We got a few berries, but not as many as we used to,” says Chugach elder Ephim Moonin Sr., whose house in the village of Nanwalek is flanked by tall salmonberry bushes. “Last year, again, there were hardly any berries.” For more than 35 years, satellites circling the Arctic have detected a “greening” trend in Earth’s northernmost landscapes. Scientists have attributed this verdant flush to more vigorous plant growth and a longer growing season, propelled by higher temperatures that come with climate change. But recently, satellites have been picking up a decline in tundra greenness in some parts of the Arctic. Those areas appear to be “browning.” Like the salmonberry harvesters on the Kenai Peninsula, ecologists working on the ground have witnessed browning up close at field sites across the circumpolar Arctic, from Alaska to Greenland to northern Norway and Sweden. Yet the bushes bereft of berries and the tinder-dry heaths (low-growing shrubland) haven’t always been picked up by the satellites. The low-resolution sensors may have averaged out the mix of dead and living vegetation and failed to detect the browning.
Scientists are left to wonder what is and isn’t being detected, and they’re concerned about the potential impact of not knowing the extent of the browning. If it becomes widespread, Arctic browning could have far-reaching consequences for people and wildlife, affecting habitat and atmospheric carbon uptake and boosting wildfire risk.
Growing greenbelt The Arctic is warming two to three times as fast as the rest of the planet, with most of the temperature increase occurring in the winter. Alaska, for example, has warmed 2 degrees Celsius since 1949, and winters in some parts of the state, including southcentral Alaska and the Arctic interior, are on average 5 degrees C warmer.
An early effect of the warmer climate was a greener Arctic. More than 20 years ago, researchers used data from the National Oceanic and Atmospheric Administration’s weather satellites to assess a decade of northern plant growth after a century of warming. The team compared different wavelengths of light — red and near-infrared — reflecting off vegetation to calculate the NDVI, the normalized difference vegetation index. Higher NDVI values indicate a greener, more productive landscape. In a single decade — from 1981, when the first satellite was launched, to 1991 — the northern high latitudes had become about 8 percent greener, the researchers reported in 1997 in Nature.
The Arctic ecosystem, once constrained by cool conditions, was stretching beyond its limits. In 1999 and 2000, researchers cataloged the extent and types of vegetation change in parts of northern Alaska using archival photographs taken during oil exploration flyovers between 1948 and 1950. In new images of the same locations, such as the Kugururok River in the Noatak National Preserve, low-lying tundra plants that once grew along the riverside terraces had been replaced by stands of white spruce and green alder shrubs. At some of the study’s 66 locations, shrub-dominated vegetation had doubled its coverage from 10 to 20 percent. Not all areas showed a rise in shrub abundance, but none showed any decrease.
In 2003, Howard Epstein, a terrestrial ecologist at the University of Virginia in Charlottesville, and colleagues looked to the satellite record, which now held another decade of data. Focusing on Alaska’s North Slope, which lies just beyond the crown of the Brooks Range and extends to the Beaufort Sea, the researchers found that the highest NDVI values, or “peak greenness,” during the growing season had increased nearly 17 percent between 1981 and 2001, in line with the warming trend. Earth-observing satellites have been monitoring the Arctic tundra for almost four decades. In that time, the North Slope, the Canadian low Arctic tundra and eastern Siberia have become especially green, with thicker and taller tundra vegetation and shrubs expanding northward. “If you look at the North Slope of Alaska, if you look at the overall trend, it’s greening like nobody’s business,” says Uma Bhatt, an atmospheric scientist at the University of Alaska Fairbanks.
Yet parts of the Arctic, including the Yukon-Kuskokwim Delta of western Alaska, the Canadian Arctic Archipelago (the islands north of the mainland that give Canada its pointed tip) and the northwestern Siberian tundra, show extensive browning over the length of the satellite record, from the early 1980s to 2016. “It could just be a reduction in green vegetation. It doesn’t necessarily mean the widespread death of plants,” Epstein says. Scientists don’t yet know why plant growth there has slowed or reversed — or whether the satellite signal is in some way misleading.
“All the models indicated for a long time that we would expect greening with warmer temperatures and higher productivity in the tundra, so long as it wasn’t limited in some other way, like [by lower] moisture,” says Scott Goetz, an ecologist and remote-sensing specialist at Northern Arizona University in Flagstaff. He is also the science team lead for ABoVE, NASA’s Arctic-Boreal Vulnerability Experiment, which is tracking ecosystem changes in Alaska and western Canada. “Many of us were quite surprised … that the Arctic was suddenly browning. It’s something we need to resolve.”
Freeze-dried tundra While global warming has propelled widespread trends in tundra greening, extreme winter weather can spur local browning events. In recent years, in some parts of the Arctic, extraordinary warm winter weather, sometimes paired with rainfall, has put tundra vegetation under enormous stress and caused plants to lose freeze resistance, dry up or die — and turn brown.
Gareth Phoenix, a terrestrial ecologist at the University of Sheffield in England, recalls his shock at seeing a series of midwinter timelapse photos taken in 2001 at a research site outside the town of Abisko in northern Sweden. In the space of a couple of days, the temperature shot up from −16° C to 6° C, melting the tundra’s snow cover. “As an ecologist, you’re thinking, ‘Whoa! Those plants would usually be nicely insulated under the snow,’ ” he says. “Suddenly, they’re being exposed because all the snow has melted. What are the consequences of that?”
Arctic plants survive frigid winters thanks to that blanket of snow and physiological changes, known as freeze resistance, that allow plants to freeze without damage. But once the plants awaken in response to physical cues of spring — warmer weather, longer days — and experience bud burst, they lose that ability to withstand frigid conditions. That’s fine if spring has truly arrived. But if it’s just a winter heat wave and the warm air mass moves on, the plants become vulnerable as temperatures return to seasonal norms. When temporary warm air covers thousands of square kilometers at once, plant damage occurs over large areas. “These landscapes can look like someone’s gone through with a flamethrower,” Phoenix says. “It’s quite depressing. You’re there in the middle of summer, and everything’s just brown.”Jarle Bjerke, a vegetation ecologist at the Norwegian Institute for Nature Research in Tromsø, saw browning across northern Norway and Sweden in 2008. The landscape — covered in mats of crowberry, an evergreen shrub with bright green sausagelike needles — was instead shades of brown, red-brown and grayish brown. “We saw it everywhere we went, from the mountaintops to the coastal heaths,” Bjerke says. Bjerke, Phoenix and other researchers continue to find brown vegetation in the wake of winter warming events. Long periods of mild winter weather have rolled over the Svalbard archipelago, the cluster of islands in the Arctic Ocean between Norway and the North Pole, in the last decade. The snow melted or blew away, exposing the ground-hugging plants. Some became encrusted in ice following a once-unheard-of midwinter rainfall. In 2015, the Arctic bell heather, whose small white flowers brighten Arctic ridges and heaths, were brown that summer, gray the next and then the leaves fell off. “It’s not new that plants can die during mild winters,” Bjerke says. “The new thing is that it is now happening several winters in a row.”
Insect invasion The weather needn’t always be extreme to harm plants in the Arctic. With warmer winters and summers, leaf-eating insects have thrived, defoliating bushes and trees beyond the insects’ usual range. “They’re very visual events,” says Rachael Treharne, an Arctic ecologist who completed her Ph.D. at the University of Sheffield and now works at ClimateCare, a company that helps organizations reduce their climate impact. She remembers being in the middle of an autumnal moth outbreak in northern Sweden one summer. “There were caterpillars crawling all over the plants — and us. We’d wake up with them in our beds.”
In northernmost Norway, Sweden and Finland in the mid-2000s, successive bursts of geometrid moths defoliated 10,000 square kilometers of mountain birch forest — an area roughly the size of Puerto Rico. The outbreak was one of Europe’s most abrupt and large-scale ecosystem disturbances linked to climate change, says Jane Jepsen, an Arctic ecologist at the Norwegian Institute for Nature Research. “These moth species benefit from a milder winter, spring and summer climate,” Jepsen says. Moth eggs usually die at around −30° C, but warmer winters have allowed more eggs of the native autumnal moth to survive. With warmer springs, the eggs hatch earlier in the year and keep up with the bud burst of the mountain birch trees. Another species — the winter moth (O. brumata), found in southern Norway, Sweden and Finland — expanded northward during the outbreak. The spring and summer warmth favored the larvae, which ate more and grew larger, and the resulting hardier female moths laid more eggs in the fall.
While forests that die off can grow back over several decades, some of these mountain birches may have been hammered too hard, Jepsen says. In some places, the forest has given way to heathland. Ecological transitions like this could be long-lasting or even permanent, she says.
Smoldering lands Once rare, wildfires may be one of the north’s main causes of browning. As grasses, shrubs and trees across the region dry up, they are being set aflame with increasing frequency, with fires covering larger areas and leaving behind dark scars. For example, in early 2014 in the Norwegian coastal municipality of Flatanger, sparks from a power line ignited the dry tundra heath, destroying more than 100 wooden buildings in several coastal hamlets.
Sparsely populated places, where lightning is the primary cause of wildfires, are also seeing an uptick in wildfires. Scientists say lightning strikes are becoming more frequent as the planet warms. The number of lightning-sparked fires has risen 2 to 5 percent per year in Canada’s Northwest Territories and Alaska over the last four decades, earth system scientist Sander Veraverbeke of Vrije Universiteit Amsterdam and his colleagues reported in 2017 in Nature Climate Change.
In 2014, the Northwest Territories had 385 fires, which burned 34,000 square kilometers. The next year, 766 fires torched 20,600 square kilometers of the Alaskan interior — accounting for about half the total area burned in the entire United States in 2015.
In the last two years, wildfires sent plumes of smoke aloft in western Greenland (SN: 3/17/18, p. 20) and in the northern reaches of Sweden, Norway and Russia, places where wildfires are uncommon. Wildfire activity within a 30-year period could quadruple in Alaska by 2100, says a 2017 report in Ecography. Veraverbeke expects to see “more fires in the Arctic in the future.”
The loss of wide swaths of plants could have wide-ranging local effects. “These plants are the foundation of the terrestrial Arctic food webs,” says Isla Myers-Smith, a global change ecologist at the University of Edinburgh. The shriveled landscapes can leave rock ptarmigan, for example, which rely heavily on plants, without enough food to eat in the spring. The birds’ predators, such as the arctic fox, may feel the loss the following year.
The effects of browning may be felt beyond the Arctic, which holds about half of the planet’s terrestrial carbon. The boost in tundra greening allows the region to store, or “sink,” more carbon during the growing season. But carbon uptake may slow if browning events continue, as expected in some regions.
Treharne, Phoenix and colleagues reported in February in Global Change Biology that on the Lofoten Islands in northern Norway, extreme winter conditions cut in half the heathlands’ ability to trap carbon dioxide from the atmosphere during the growing season.
Yet there’s still some uncertainty about how these browned tundra ecosystems might change in the long-term. As the land darkens, the surface absorbs more heat and warms up, threatening to thaw the underlying permafrost and accelerate the release of methane and carbon dioxide. Some areas might switch from being carbon sinks to carbon sources, Phoenix warns.
On the other hand, other plant species — with more or less capacity to take up carbon — could move in. “I’m still of the view that [these areas] will go through these short-term events and continue on their trajectory of greater productivity,” Goetz says.
A better view The phenomena that cause browning events — extreme winter warming, insect outbreaks, wildfires — are on the rise. But browning events are tough to study, especially in winter, because they’re unpredictable and often occur in hard-to-reach areas. Ecologists working on the ground would like the satellite images and the NDVI maps to point to areas with unusual vegetation growth — increasing or decreasing. But many of the browning events witnessed by researchers on the ground have not been picked up by the older, lower-resolution satellite sensors, which scientists still use. Those sensors oversimplify what’s on the ground: One pixel covers an area 8 kilometers by 8 kilometers. “The complexity that’s contained within a pixel size that big is pretty huge,” Myers-Smith says. “You have mountains, or lakes, or different types of tundra vegetation, all within that one pixel.” At a couple of recent workshops on Arctic browning, remote-sensing experts and ecologists tried to tackle the problem. “We’ve been talking about how to bring the two scales together,” Bhatt says. New sensors, more frequent snapshots, better data access and more computing power could help scientists zero in on the extent and severity of browning in the Arctic.
Researchers have begun using Google Earth Engine’s massive collection of satellite data, including Landsat images at a much better resolution of 30 meters by 30 meters per pixel. Improved computational capabilities also enable scientists to explore vegetation change close up. The European Space Agency’s recently launched Sentinel Earth-observing satellites can monitor vegetation growth with a pixel size of 10 meters by 10 meters. Says Myers-Smith: “That’s starting to get to a scale that an ecologist can grapple with.”
In other star systems, some moons could escape their planets and start orbiting their stars instead, new simulations suggest. Scientists have dubbed such liberated worlds “ploonets,” and say that current telescopes may be able to find the wayward objects.
Astronomers think that exomoons — moons orbiting planets that orbit stars other than the sun — should be common, but efforts to find them have turned up empty so far (SN Online: 4/30/19). Astrophysicist Mario Sucerquia of the University of Antioquia in Medellín, Colombia and colleagues simulated what would happen to those moons if they orbited hot Jupiters, gas giants that lie scorchingly close to their stars (SN: 7/8/17, p. 4). Many astronomers think that hot Jupiters weren’t born so close, but instead migrated toward their star from a more distant orbit. As the gas giant migrates, the combined gravitational forces of the planet and the star would inject extra energy into the moon’s orbit, pushing the moon farther and farther from its planet until eventually it escapes, the researchers report June 27 at arXiv.org.
“This process should happen in every planetary system composed of a giant planet in a very close-in orbit,” Sucerquia says. “So ploonets should be very frequent.”
Some ploonets may be indistinguishable from ordinary planets. Others, whose orbits keep them close to their planet, could reveal their presence by changing the timing of when their neighbor planet crosses, or transits, in front of the star. The ploonet should stay close enough to the planet that its gravity can speed or slow the planet’s transit times. Those deviations should be detectable by combining data from planet-hunting telescopes like NASA’s TESS or the now-defunct Kepler, Sucerquia says. Ploonethood may be a relatively short-lived phenomenon, though, making the worlds more difficult to spot. About half of the ploonets in the researchers’ simulations crashed into either their planet or star within about half a million years. And half of the remaining survivors crashed within a million years.
Even with few visible survivors, ploonets could help explain some bizarre exoplanetary features. Moon debris from such crashes could lead to giant ring systems around planets, like the 37 rings that encircle exoplanet J1407b, the team says.
Or, if the ploonet had an icy surface or an atmosphere before moving close to its star, the star’s heat would evaporate it, giving the ploonet a tail like a comet’s. Evaporating ploonets zipping by with a long light-blocking tail could explain strangely flickering stars like Tabby’s star, Sucerquia says (SN: 12/22/18, p. 9).
“Those structures [rings and flickers] have been discovered, have been observed,” Sucerquia says. “We just propose a natural mechanism to explain [them].”
While the solar system doesn’t have any hot Jupiters, ploonethood may be possible here, too. Earth’s moon is moving slowly away from the Earth, at a rate of about 4 centimeters per year. When it eventually breaks free, “the moon is a potential ploonet,” Sucerquia says — although that won’t happen for about 5 billion years.
The study is a good first step for thinking about what would happen to exomoons in real planetary systems, says planetary astrophysicist Natalie Hinkel of the Southwest Research Institute in San Antonio, who wasn’t involved in the new work. “Nobody’s looked at the problem quite like this,” she says. “It adds to the layers of how complex these systems are.”
Plus, ploonet is “a wonderful name,” Hinkel says. “Normally I sort of eye-roll at these made-up names, but this one is a keeper.”
A praying mantis depends on precision targeting when hunting insects. Now, scientists have identified nerve cells that help calculate the depth perception required for these predators’ surgical strikes.
In addition to providing clues about insect vision, the principles of these cells’ behavior, described June 28 in Nature Communications, may also lead to advances in robot vision or other automated systems.
So far, praying mantises are the only insects known to be able to see in 3-D. In the new study, neuroscientist Ronny Rosner of Newcastle University in England and colleagues used a tiny theater that played praying mantises’ favorite films — moving disks that mimic bugs. The disks appeared in three dimensions because the insects’ eyes were covered with different colored filters, creating minuscule 3-D glasses. As a praying mantis watched the films, electrodes monitored the behavior of individual nerve cells in the optic lobe, a brain structure responsible for many aspects of vision. There, researchers found four types of nerve cells that seem to help merge the two different views from each eye into a complete 3-D picture, a skill that human vision cells use to sense depth, too.
One cell type called a TAOpro neuron possesses three elaborate, fan-shaped bundles that receive incoming visual information. Along with the three other cell types, TAOpro neurons are active when each eye’s view of an object is different, a mismatch that’s needed for depth perception.
The details of the various types of nerve cells, and how they might receive, combine and send visual information, suggest that these insects’ vision may be more sophisticated than some scientists had thought, the team writes. And the principles guiding praying mantis depth perception may be useful to researchers working on improving machine vision, perhaps allowing artificial systems to better sense the depths of objects.
A new biomaterial delivered to the heart soon after a heart attack can heal damaged tissue from the inside out.
Heart attacks kill cardiac muscle tissue, scarring the heart and leaving permanent damage after just six hours. The damage prevents the heart from functioning properly. If there was a way to begin healing damaged tissue soon after a heart attack, doctors could prevent scar tissue from developing.
“In an ideal world, you treat a patient immediately when they’re having a heart attack to try to salvage some of the tissue and promote regeneration,” says Karen Christman, a bioengineer at the University of California, San Diego. The pursuit of this ideal inspired Christman, along with a team of researchers, to develop the biomaterial. In rodents and pigs, it appears to repair tissue damage and reduce inflammation directly after a heart attack, Christman and colleagues report December 29 in Nature Biomedical Engineering.
“I think it has a lot of potential,” Vimala Bharadwaj, a biomedical scientist at Stanford University who was not involved in the research. The paper “is definitely good proof of concept for what they’re trying to do.”
Previously, researchers found that stem cells derived from body fat can be used to heal bones, muscles and the heart (SN: 3/9/16). Christman wanted to work with the extracellular matrix, the lattice of proteins that provide structural support to the cells in cardiac muscle tissue. Like stems cells, it has regenerative abilities but is much less expensive, she says.
In 2009, Christman’s team produced a hydrogel using particles from this matrix. Trials in rats and later in humans showed that the material bonded to damaged areas and promoted cell repair and growth. However, due to relatively large particles of the hydrogel, it could be delivered to the heart only via a needle.
“Poking the heart with a needle could set off an arrhythmia,” says Christman. To use this treatment, doctors would need to wait a few weeks until the heart is more stable and the chance of these irregular heartbeats decreases. And that would be too late to prevent scarring.
The team took the previously created hydrogel, sifted out the larger particles with a centrifuge so only nanoparticles remained, and added water to dilute the mixture. That created a material thin enough to deliver to heart blood vessels intravenously. Based on the nanoparticles’ size, the team expected the mixture would slip through any gaps in cardiac blood vessels caused by the heart attack and adhere to the surrounding tissue. Once there, it would create a protective barrier while the heart healed.
Instead, animal experiments showed that the extracellular matrix material bound to the leaky vessels, preventing some inflammatory cells from moving into the heart tissue in the first place and causing further damage. The material reduced inflammation in the heart and stimulated the healing process by encouraging cell growth, the team reports.
Further safety studies will be needed to get the biomaterial ready for clinical trials. The first trial in humans will most likely be for repairing cardiac tissue post–heart attack. “A lot of my motivation is moving things out of the lab, actually into the real world,” Christman says.
Another real-world application of the biomaterial could be treatment for leaky blood vessels in other hard-to-access organs, including in the brain after a traumatic injury, Christman notes.
While Bharadwaj finds that application potentially promising, she says tests are needed to see whether the biomaterial improves headaches and cognitive or memory deficits in the brain after a traumatic injury. That’s needed to gauge whether it really is an effective TBI treatment.
As early as 252 million years ago, some plants may have curled up their leaves at night for a cozy “sleep.”
Fossilized leaves of two now-extinct Gigantonoclea species bear signs of nyctinasty, or circadian rhythmic folding at night, researchers report February 15 in Current Biology. That would make these specimens the first known fossilized examples of this curious plant behavior, the team says.
The two leaf fossils were discovered in a rock layer in southwestern China that dates to between 259 million and 252 million years ago. In both species, the leaves were broad, with serrated edges. But most curiously, they bear oddly symmetrical holes. Insects made those holes while feeding on the leaves while they were folded, say paleontologist Zhuo Feng of Yunnan University in Kunming, China and colleagues. Similar symmetrical patterns of insect damage in leaf fossils can be used to distinguish folding behavior from leaves that might have shriveled as the plant died, the team says.
Modern plants, including many in the legume family such as the orchid tree, that fold and unfold their leaves use specialized cells called pulvinus cells, which act somewhat like muscles (SN: 2/3/23). By shifting water from one part of the leaf to another, the cells can bloat or deflate, allowing the leaves to fold or curl.
These cells would be at the base of the leaves, which weren’t preserved in the fossils, so it’s not possible to say whether these ancient plants also had pulvinus cells, the team says. Although it’s also hard to prove this was nighttime behavior, the leaves would also have had to be folded long enough for insects to do their munching. But the find does suggest that such leaf folding emerged independently in different plant lineages: Nearly all the modern plants that do this are angiosperms, or flowering plants. But Gigantonoclea plants were gymnosperms, seed-producing plants such as conifers and ginkgos.
