China’s ‘space greenhouse’ grows more crops with improved yield, quality

With the China Manned Space Agency's announcement on Thursday of an open call for space breeding experimental projects, China's "space greenhouse" is ready to embrace the planting of more new species, as recent years have seen a significant increase in the variety of crops that have toured around space. Many of these crops have already entered ordinary households and are served on dinner tables, and space breeding is playing a greater role in contributing to China's food security. 

"Staple crops and vegetable crops are the main species that have been promoted on a large scale on the ground after space breeding. They include rice, wheat, corn, peppers, tomatoes, space lotus and other varieties," Zhao Hui, secretary-general of the Space Breeding Industry Innovation Alliance, told the Global Times. 

Many space-bred crops have now been planted on a large scale, Zhao said. For example, the rice seeds carried by the Shenzhou-10 manned mission have produced nearly 10 new varieties of high-quality, high-yielding rice in the past five years.

The average yield of wheat production in China is around 400-600 kilograms per mu (0.67 hectares), Zhao said, while the new variety of wheat seeds bred from the ones carried onboard the Shenzhou-10 spacecraft in 2013 will have an average yield of more than 800 kilograms per mu. The new variety of seeds is expected to be planted over an area of more than 500,000 mu from 2021 to 2023. 

What's more, more than 5,000 vegetable variant strains of good quality have been bred onboard the Shenzhou series of manned spacecraft, creating over 20 new varieties of vegetables such as space peppers and space tomatoes. 

The vitamin C content in space pepper is 20 percent more than ordinary ones, and they are available for market sale some 15 days earlier. The yield is also significantly improved, bringing considerable economic benefits to farmers.

In addition to staple crops and vegetables, the yield of grass and flowers and Chinese herbal seeds has also increased through space breeding.

Other than boosting yields and quality of seeds, the benefit of China's space breeding is also reflected in its contribution to the nation's food security.

The China space station, completed last year, has now entered the application and development phase. A large number of biological samples have been carried to the in-orbit station, obtaining space mutagenesis under cosmic radiation in the microgravity environment during spaceflight.  

A great number of experimental materials have returned to Earth with the Shenzhou spacecraft and have been handed over to researchers for seed selection and ground breeding, the Global Times has learned. Shenzhou-14 and -15 have carried more than 1,000 crop seeds and microbial strains from over 100 institutions, and Shenzhou-12 and -13 also returned more than 1,000 seeds from 88 institutions. 

"At present, whether in laboratory testing of microbial strains or experimental planting of crop materials, important mutant strains with scientific research value and application potential have been found, such as rice in South China, forage grass in Southwest China's Sichuan Province, cotton in Central China's Henan Province, and maple, fir, and red beech for forest breeding," Zhao noted. 

These valuable strains will lay the foundations for the innovation of China's agricultural and forestry resources and play an important role in the development of the country's food security and ecological civilization, he said. 

Space breeding has produced more than 240 varieties of staple crops in China, significantly improving crop yield and quality and increasing grain production by about 1.6 billion kilograms, the Global Times has learned. The varieties, with optimized cultivation techniques, have greatly reduced costs, bringing farmers more income. 

For example, the new variety of space rice in South China can be sown directly, which avoids the transplanting process and reduces the burden on farmers. 

Space mutagenesis has greatly improved the properties and quality of materials, and further expanded their commercial use. 

At present, staple food crops such as rice and wheat, or space peppers, tomatoes and eggplants have all been served on people's tables. With a large number of breeding materials sent into space in recent years, more new varieties with new traits and tastes will enter the market soon in the future, enriching people's lives, Zhao said. 

As for safety issues from space-bred crops that aroused public concern, Zhao said the public need not worry at all. He explained that for one thing, the introduction of exogenous or endogenous genes is not involved in the process of space mutagenesis, so it is no different from traditional physical radiation breeding; for another thing, under the protection of the spacecraft, the radiation concentration is much lower than that of traditional radiation mutagenesis, and the offspring of spaceflight breeding will not be radioactive.

"Our taikonauts on the China Space Station and astronauts on the International Space Station have all eaten space lettuce and other kinds of space-bred crops and no safety issues have ever occurred. That suggests that space-bred food is safe," Zhao noted. 

Huawei completes switch from US products to in-house system in 88 overseas units

Chinese technology giant Huawei has successfully replaced internal software management systems it once sourced from US vendors with its own in-house version in 88 overseas subsidiaries, as the company continues to reduce foreign reliance amid prolonged US curbs.

According to an article published on Huawei's online community for its employees Xinsheng.huawei.com, the 88 overseas units in 75 countries were the first batch of Huawei's global branches to complete the switch to its self-developed MetaERP, covering business sectors including cloud computing, devices, and information and communication technology. 

Huawei said it plans to accomplish the switchover in all of its more than 200 overseas units within the year.

ERP software is used by companies to manage key business operations ranging from accounting to supply chain management. It is widely seen as the most critical enterprise management IT system.

"The global switchover to MetaERP, and its ability to support the normal operations of Huawei's diverse lines of business worldwide, will prove to be an all-around victory," said the company.

In May 2019, the US Commerce Department added Huawei to a trade blacklist over alleged security concerns. The move has cut it off from a range of services and products, including ERP tools it largely purchased from US vendors.

Since then, the company has launched a transformation project to guarantee ERP continuity. After three years of efforts, the company successfully piloted the MetaERP system in Malaysia in September 2021, and applied it to key subsidiaries including Huawei Technologies in July 2022. 

In January 2023, MetaERP successfully supported the company's yearly settlements, representing a key victory for the system.

In late April, Huawei held an internal ceremony to celebrate the switch in Dongguan, South China, attended by the company's rotating Chairperson Meng Wanzhou.

"We were cut off from our old ERP system and other core operation and management systems more than three years ago. Since then, we have been able not only to build our own MetaERP, but also to manage the switch and prove its capabilities. Today we are proud to announce that we have broken through the blockade. We have survived!" Tao Jingwen, a Huawei board member and president of the quality, business process and IT management department, said during the ceremony.

China successfully tests high-thrust engine for moon landing

China successfully carried out a trial test on the main engine of the Long March-10, a new carrier rocket designed for manned moon landing missions, on Saturday, as the country actively makes progress on the road to realizing its goal of landing taikonauts on the moon by the year 2030.

The test assessed all the requirements for the engine, and provided strong support for the solidification for its technical state, the establishment of the technical baseline of the product and improving reliability, the Global Times learned from the China Aerospace Science and Technology Corporation (CASC) 6th Academy on Sunday.

The engine used in the test employs advanced liquid oxygen as fuel and can reach a thrust of 130 tons. It is an updated version of China's strongest active rocket engine, which has a thrust of 120 tons and is used in rockets including the Long March-5.

Although the thrust of the engine has only improved by 10 tons, the first stage of the Long March-10 will reportedly carry 21 engines. This will add another 210 tons of the thrust in total, Wang Yanan, chief editor of Beijing-based Aerospace Knowledge magazine, told the Global Times on Sunday.

Zhou Xianqi, a researcher from the CASC, told the Global Times that "the engine has met all the requirements in the Saturday test." He noted that the engine's startup, shutdown and running stability under high and low conditions have been tested, and all relevant parameters have been obtained.

During the development of the engine, many new materials, new processes and new technologies were applied. Researchers have overcome a number of key technical problems such as the sequence of the engine's start-up and shutdown, continuously changing the engine's thrust at scale, in addition to the engine's long life and improved reliability, laying a solid foundation for the engine's future development, the Global Times learned.

"In the second half of this year, we will conduct several high-altitude simulation tests to determine the relevant performance and parameters of this engine," Zhou added.

The new carrier rocket has mainly been developed for the purpose of sending spacecraft and moon landers into the Earth-moon transfer orbit, Rong Yi, a rocket expert with the CASC China Academy of Launch Vehicle Technology, was quoted as saying by the Xinhua News Agency on Saturday.

The rocket uses liquid hydrogen, liquid oxygen and kerosene as propellants. It has a total length of about 92 meters, a takeoff weight of about 2,187 tons, a takeoff thrust of about 2,678 tons, and a carrying capacity of no less than 27 tons for the Earth-moon transfer orbit, according to Xinhua.

A non-booster configuration of the new rocket is capable of conducting missions for transporting taikonauts and cargo to the space station. Its total length is about 67 meters, the takeoff weight is about 740 tons, the takeoff thrust is about 892 tons, and the low-Earth orbit carrying capacity is no less than 14 tons.

The Long March-10 serves as strategic pillar for China's aim to land taikonauts on the moon before 2030. Preparations for the maiden flight are expected to start in 2027, Rong told Xinhua.

Experts are confident that China will be able to accomplish a manned moon landing before 2030 if the Long March-10 can carry out its maiden flight in 2027, as many parts of the carrier rocket such as the engine, core module and other technical structures are upgrades from those in the Long March-5 series of carrier rockets and so have already been fully tested, according to Wang.

China revealed on July 12 that its primary plan is to carry out a manned moon landing before 2030. To achieve this goal, the country will attempt to use two launch vehicles to send a moon surface lander and manned spacecraft into lunar orbit, which will then rendezvous and dock with each other. Following this maneuver, taikonauts onboard the manned spacecraft will enter the lander.

Apart from the progress with the high-thrust engine and the Long March-10 carrier rocket, China is also actively developing spacecraft and lunar landers for the manned moon landing.

China's new-generation of manned spacecraft successfully entered orbit by Long March-5B carrier rocket and returned to Earth during tests in May 2020. Based on the new spacecraft, China is also advancing development of near-Earth spacecraft designed to accommodate four to seven crew members, building a future for space tourism.

China's lunar lander weighs about 26 tons and consists of a lunar landing module and propelling module. It can bring taikonauts down from lunar orbit to land on the moon and send them back to lunar orbit. The lunar lander is also able to conduct autonomous flight. The lunar lander will also carry scientific payloads for exploration focusing on lunar geology and lunar physics, observation, space life sciences, as well as deep drilling on the lunar surface and utilization of lunar resources, according to Xinhua.

In addition to the lunar rover, China also plans to develop a lunar mobile laboratory with large-scale mobile capability, which can realize long-term unmanned autonomous activities on the lunar surface and support taikonauts for short time stays, Xinhua said.

‘I will never go to Japanese restaurants again’: Chinese netizens concerned over Japan’s toxic dumping

As Japan began dumping nuclear-contaminated wastewater from the Fukushima nuclear power plant into the Pacific Ocean on Thursday despite strong opposition from the international community, Chinese netizens expressed their anger and concern, with a large number of netizens saying that they would no longer go to Japanese restaurants.

Affected by Japan's "forced dumping," many domestic Japanese restaurants have told media outlets that they will adjust their product lines, and seafood will be selected from domestic sources or imported from other coastal countries. Some even said that they will consider switching to other cuisines.

Experts said that Japan's dumping of nuclear-contaminated wastewater will have a clear impact on Chinese people's public opinion toward Japan. China is the largest importer of seafood from Japan, and many Chinese people are fond of eating Japanese food. The dumping will undoubtedly have a very negative impact on the national image of Japan, as well as on the safety of Japanese brands, especially food, a research fellow from the Institute of Japanese Studies at the Chinese Academy of Social Sciences told the Global Times.

In a poll conducted on Sina Weibo, more than 200,000 netizens said they would never patronize Japanese restaurants again. Many netizens living in coastal cities also expressed their anger: "We grew up near the sea, and the sea is like our mother. Japan's practice of contaminating the sea is incomprehensible and unforgivable."

Guo Fan, the director of Chinese sci-fi blockbuster series The Wandering Earth, forwarded an image from the famous manga Doraemon which said: "Dumping garbage into the sea is ill-bred." His post triggered a large number of reposts and resonance from netizens.

In addition, some netizens summed up the concept of environmental protection discussed in several Japanese animated works and television shows. 

"Japanese anime is trying to promote the protection of the sea, but the Japanese government is determined to discharge sewage into the sea. How ironic!" one netizen commented.

China's famous illustration team Wuheqilin also posted a new artwork in response to the dumping. In the image, Japan is depicted as a mutated monster, symbolizing that the nation has suffered from nuclear radiation and is now unrecognizable. The artwork portrays the monster disgorging nauseating yellow pollutants into the sea, creating a disturbing image. Titled "Are You Taking Humanity Down with You, Bastard?" it quickly went viral on Sina Weibo, garnering more than 360,000 likes.

The Hong Kong SAR decided on Tuesday to ban the import of fish products from 10 cities and prefectures in Japan from Thursday, including all live, frozen, refrigerated, dried or otherwise preserved fish products, sea salt, and unprocessed or processed seaweed.

Some media outlets reported that since Hong Kong people have long been fond of sashimi, many people have criticized Japan's dumping of nuclear-contaminated wastewater as disregarding public safety, saying that they will never eat sashimi again, while also expressing that they are worried how it will affect the aquatic products of other countries if the sea becomes polluted. 

According to media reports, many Japanese supermarkets in Hong Kong have already labeled their seafood with the origin of the products.

Brazil study strengthens link between Zika virus, birth defects

In a study of pregnant women in Brazil, nearly 30 percent of those infected with Zika virus had babies with fetal abnormalities, researchers report March 4 in the New England Journal of Medicine.

Zika virus is the leading suspect for what’s causing a spike in certain birth defects reported in Brazil. Scientists have previously found traces of Zika in the brains of fetuses with microcephaly (a birth defect that leaves babies with smaller-than-normal heads). And one study has reported that the virus can infect and kill a cell type crucial to developing brains (SN Online: 3/4/16).

The new study enrolled 88 pregnant women from Rio de Janeiro who had developed a rash (a sign of Zika infection). They tracked the women throughout their pregnancies; so far, eight have given birth. Of the 42 women who both tested positive for Zika and received fetal ultrasounds, 12 of the women’s babies had abnormalities (including small heads, damaged brain tissue, and low levels of amniotic fluid).

Despite mild clinical symptoms, Zika infection during pregnancy appears to be linked with grave outcomes, the authors write.

Comets carried noble gases to Earth

Asteroids probably ferried water to an infant Earth (SN: 5/16/15, p. 18), but they weren’t responsible for our planet’s entire chemical inventory. Comets might have trucked in noble gases and much of the raw material needed for life, researchers suggest online March 9 in Earth and Planetary Science Letters.

Noble gases don’t play well with the other elements. They typically shun chemical reactions, which means their abundances haven’t changed much since the formation of the solar system. Comets are thought to be frozen relics from the birth of the planets, but until recently researchers didn’t know how much of any noble gas comets carried.
That changed shortly after the Rosetta spacecraft arrived at comet 67P/Churyumov-Gerasimenko in August 2014 (SN: 9/6/14, p. 8) and made the first measurement of argon in a cometary atmosphere. It’s not much — roughly 1/100,000 the amount of water — but it’s several orders of magnitude more than the abundance of argon in icy asteroids. And that’s enough for comets to have been a major source of argon (and presumably other noble gases) to Earth, Bernard Marty, a geochemist at Petrographic and Geochemical Research Centerin Vandœuvre-lès-Nancy, France, and colleagues report.

The delivery arrived during the Late Heavy Bombardment about 600 million years after the start of the solar system, Marty and collaborators suggest. That’s when the moon (and supposedly Earth) was pummeled by debris from the outer solar system as the giant planets abruptly settled into their current orbits.

Argon might seem of little relevance to everyday life. But “if argon came from comets, we can make some inferences about how much prebiotic material came in comets too,” Marty says. And those other goodies, such as amino acids, might matter a great deal. Assuming that all the argon in Earth’s atmosphere came from comets, and that cometary levels of amino acids (which no one has measured) are similar to what’s found in meteorites known as carbonaceous chondrites, the researchers calculated how much amino acids comets could have delivered to Earth. Dust collected from comet 81P/Wild 2 by the Stardust spacecraft in 2004 showed some chemical similarities between its quarry and those meteorites.

It’s a rough calculation, Marty admits, and it assumes that the deliveries survived the impacts. But the team estimates that the amount of amino acids supplied by comets could roughly equal the total mass found in all organisms from paramecia to plants and people.

“I think it’s an interesting exercise,” says Conel Alexander, a planetary scientist at the Carnegie Institution for Science in Washington, D.C. “But it’s full of so many uncertainties. My worries are that we still know so little about comet composition.” The amount of cometary argon, for example, is based on just one comet. Other comets have shown tremendous variability, for example, in the relative amounts of water isotopes. Researchers also don’t have a good handle on the concentration of other noble gases, such as xenon, lurking in comets.
There’s also uncertainty about the Late Heavy Bombardment that presumably brought the comets to Earth. Evidence for the influx of debris comes from a spike in craters on the moon roughly 4 billion years ago. But the timing comes from lunar rocks collected by Apollo astronauts and those samples might all have come from one basin, says Alexander. Rather than revealing the ages of many craters, the moon rocks might record the date of a single run-in with a giant intruder.

Recent computer simulations also indicate that the giant planet tango that allegedly triggered the bombardment should have removed at least one of the inner planets, which doesn’t appear to have happened. To avoid that catastrophe, the gas giants had to have settled down before the rocky planets finished forming and so wouldn’t have been available to fling things at Earth 600 million years later.

Should C-section babies get wiped down with vagina microbes?

Bacteria is back, baby. After decades of gobbling antibiotics and overzealous hand sanitizing, it’s now clear that the bacteria that live in and on our bodies can help keep us healthy. That realization is what led scientists to rub brand-spanking-new babies with fluid from the mothers’ vaginas.

Like about a third of babies born in the United States, these babies were born by C-section, and so missed out on a trip through the birth canal, where their bodies would have been propelled with viselike pressure through a channel coated with microbe-laden fluid. This crushing, juicy journey coats babies with their mothers’ vaginal microbes. Babies born by C-section are instead colonized with bacteria that live on skin (possibly picked up from the dust in the hospital operating room).

That difference may have important implications for future health, some scientists think. Studies have hinted that microbes picked up during a vaginal birth can sculpt newborns’ immune systems in ways that combat disorders including obesity, asthma and allergies. So it follows that replacing those missing vaginal microbes might be a good thing.

Scientists led by Maria Dominguez-Bello of New York University and the University of Puerto Rico in San Juan took a first step in testing that idea with the vaginal wipe-down experiment. An hour before a C-section, doctors inserted a square of wet, folded gauze into four women’s vaginas to slurp up the fluid. This microbe-laden gauze came out right before the C-sections began. Within a minute of birth, the newborns were swabbed with the gauze, first on their lips, then their faces, trunks, arms and legs, genitals, anuses and, finally, their backs. The whole-body rubdown took about 15 seconds.

Those 15 seconds led to bacterial changes that lasted through the newborns’ first month, the researchers reported February 1 in Nature Medicine. Compared with babies born via C-section who didn’t get swabbed, the four swabbed babies had bacterial species on their mouths, skin and guts that were more similar to those in their mothers’ vaginas. That resemblance suggests that swabbing could transform the newborns’ microbes in a way that might ultimately be beneficial.

The study gives some much-needed heft to the idea that microbes matter. By showing that newborns’ bacteria can be manipulated in a pretty simple way, the study opens the door for other tests of whether this microbial rehab is a good thing.

But the study is preliminary, the authors stress in their paper. The results come from four babies, with only a month of follow-up. It’s possible that these changes don’t stick around. It’s also possible that these microbes don’t actually improve health.

Those outstanding questions haven’t deterred some intrepid parents of babies born by C-section who want to try “vaginal seeding,” says pediatric infectious disease expert Aubrey Cunnington of Imperial College London. Over the last several years, news reports have raised interest, prompting some parents to request the procedure. On neonatal infection rounds last summer, a fellow doctor brought up a troubling story. “She described a recent situation where she had needed to stop a midwife from performing seeding, because the mother had a genital herpes infection,” Cunnington says.

That situation raised an important issue — fluid from a mother’s vagina may carry beneficial microbes, but it could also hold bacteria and viruses that could harm a newborn, Cunnington and colleagues wrote in an editorial published February 23 in BMJ. “Demand has outstripped both professional awareness and professional guidance on this practice,” he and his colleagues wrote in their editorial.

A lack of guidance is worrisome, he argues, because the procedure could unknowingly expose newborns to dangerous bugs, pathogens that babies born by C-section usually avoid. Group B streptococcus, which is carried by about 30 percent of women, can trigger meningitis and fatal septicemia, he says. Herpes simplex virus can lead to death and disability in newborns. And chlamydia and gonorrhea can cause severe eye infections.

Cunnington argues that those potential risks, coupled with unproven and potentially slim benefits, makes the procedure a no-go for now. “On balance, I don’t think the potential benefit outweighs the risk,” he says. Health practitioners at his hospital have been advised not to perform the procedure. (But because the swabbing is so simple, they can’t stop parents, or more realistically, another helper, from performing it themselves.) Staff at other hospitals vary in their willingness to help.

In the swabbing study, the protocol came with built-in safeguards. The women were tested for pathogens, and showed no signs of viral or bacterial infections. And the gauze was handled carefully so that it didn’t pick up new germs. Those precautions should be followed by any hospital or DIYer.

Like any decision — particularly those related to pregnancy and children — choosing whether to swab a baby born by C-section comes with a murky risk assessment. Some of that risk can be lowered by ruling out pathogens such as group B strep and STDs, tests that are usually offered to pregnant women in the United States. Cunnington points out that group B strep test results aren’t always reliable, and that STDs can be picked up after the tests. As a result, looking for those pathogens close to the time of delivery can make microbe swabbing less risky.

If you don’t feel like an adventurous self-experimenter, you can tend to your newborn’s microbes in other ways. Breastfeeding and avoiding unnecessary antibiotics may both encourage good microbes to flourish, no swabbing necessary.

Turning water to steam, no boiling required

A new, extremely black material can turn water into steam using only sunlight, without the need to bring the water to a boil. Made of gold nanoparticles tens of billionths of a meter wide affixed to a scaffold pocked with tiny channels, or “nanopores,” the material is a deep black color because it reflects very little visible light. It is 99 percent efficient at absorbing light in the visible spectrum and parts of the infrared spectrum, researchers report April 8 in Science Advances.

Thanks to its highly porous structure, the material floats on the surface of water, allowing it to soak up the sun’s rays. When light of a certain wavelength hits a gold nanoparticle inside one of the nanopores, it stirs up the electrons on the surface, sloshing them back in forth in an oscillation known as a plasmon. These plasmons produce localized, intense heating, which vaporizes the water nearby.
The wavelength of light that excites a plasmon depends on the size of the nanoparticle. So in order to take advantage of as much of the sun’s output as possible, the group interspersed a variety of sizes of gold nanoparticles in the pores, which could therefore absorb a range of wavelengths.
It’s not the first time scientists have produced steam with plasmonic materials, but the new material improves the efficiency of the process, converting up to 90 percent of the light’s energy into steam, says materials scientist Jia Zhu of Nanjing University in China, a leader of the research group.

“They have really come out with a very intriguing solution,” says mechanical engineer Nicholas Fang of MIT, who was not involved in the research. The efficiency isn’t quite as high as scientists have achieved with certain other types of materials, like carbon nanotubes, Fang says. But the new material should be cheaper to manufacture.

Efficient steam generation could be useful for desalination, producing freshwater from salty water, says Zhu. Other potential applications range from sterilization to running steam engines. “Steam can be used for many other things,” he says. “It is a very useful form of energy.”

New species of hairy weevil named after Chewbacca

In a galaxy far, far away, Chewbacca is a 7.5-foot-tall Wookiee. On Earth, he’s a small furry beetle.

Researchers discovered four new species of weevils on an island off the coast of Papua New Guinea, one of which they named after the lofty Star Wars character. Trigonopterus chewbacca is a black, flightless beetle about 3 millimeters long that thrives in the tropical forests of New Britain. Although T. chewbacca doesn’t resemble its namesake in size, the dense hairlike scales covering its head and legs reminded the researchers of Chewbacca’s fur.

Before these finds, Trigonopterus beetles hadn’t been spotted on New Britain. The discovery of T. chewbacca and its three relatives, T. obsidianus, T. puncticollis and T. silaliensis, suggests that the genus colonized the island at least four separate times, the team reports April 21 in ZooKeys.

T. chewbacca joins the ranks of other insects with a Star Wars moniker. Among its peers: a furry moth also named after the heroic Wookiee, a wasp named for Yoda and a Darth Vader slime-mold beetle.

Vultures are vulnerable to extinction

Vultures are the birds everyone loves to hate. Even though you have nothing to fear from them — unless you’re dead — vultures’ steady diet of carrion will gross most people out. That diet may also be responsible for the birds’ quick and steep declines around the globe, a new study shows.

It’s not the dead bodies that are killing vultures, though. It’s the poisons with which humans have laced those meals, both intentionally and inadvertently, Evan Buechley and Çağan Şekercioğlu of the University of Utah in Salt Lake City conclude in the June Biological Conservation.

The team went searching for an explanation to something Şekercioğlu had reported in 2004 and is still true today — that vultures are the most threatened group of birds. Of the 22 species of vultures, nine are now critically endangered, three are endangered and four are near threatened, according to the International Union for Conservation of Nature, which tallies endangered species.

Buechley and Şekercioğlu were looking for an explanation of why these scavenging species (called “obligate scavengers” because they depend almost entirely on carrion for survival) are doing so poorly but “facultative scavengers” — birds such as storks, gulls and crows that can also eat things other than carrion and trash — tend to be doing well and even increasing in numbers in many cases. The researchers collected ecological information and population trend data on the 22 species of vultures and other avian scavengers and then tried to figure out what made the vultures so vulnerable.

Some aspects of biology do contribute to the vulture declines, the team found. These are large animals that live long and don’t produce a lot of offspring. That means that populations can take a long time to recover from bird deaths. But the ultimate cause of those deaths is what is disturbing — dietary toxins, which are the primary cause of declines in 14 of the 16 threatened and near-threatened vulture species, the team found.

Those toxins come in various forms. In India and Southeast Asia, it’s the cattle drug diclofenac, which causes kidney failure in any vulture unlucky enough to come across a cow that didn’t survive its medical treatment. Diclofenac is a problem for vultures in Africa, too, (and now Spain), but there the birds have also fallen victim to the poisons used to kill hyenas, jackals and lions in response to dead livestock. Wildlife poachers have also deliberately poisoned their prey in an effort to get rid of the circling vultures that can alert authorities to their crime. (Buechley and Şekercioğlu discovered a 2007 incident in Namibia in which a poisoned elephant carcass killed as many as 600 birds.) And in Europe and the Americas, carcasses laced with rodenticides, insecticides and lead from ammunition are also killing vulture species.

Without vultures, some of these ecosystems are already having problems. Other scavenging species aren’t quite able to fit into the vulture niche. They can’t eat as much and they don’t have stomachs equipped to kill deadly microbes, like vultures do. That means anything that does eat carrion could potentially spread disease. Populations of scavenging pests, like rats and feral dogs, have already skyrocketed in some places as these animals feast on what vultures would have once dealt with. Perhaps not surprisingly, that has led to problems, such as an increase in dog bites in India that has resulted in thousands of human deaths from rabies.

Much of the vulture declines could be easily solved by banning the chemicals that kill them, the researchers note. Because while vultures may be more inherently vulnerable to extinction than other bird species, due to their biology, their importance to the global ecosystem — and our own health — makes them too valuable to let slip away.