Continuing a tradition that has lasted for 34 years, China's foreign minister has once again chosen Africa as the first foreign visit destination for the new year, and this time the visit will cover two countries in North Africa - Egypt and Tunisia - and two in West Africa - Togo, and Cote d'Ivoire - per the announcement of the Chinese Foreign Ministry spokesperson on Thursday.
Chinese Foreign Minister Wang Yi's first overseas trip in 2024 will take place between January 13 to 18 at the invitation of the four African countries, Mao Ning, the spokesperson, said on Thursday.
After his visit to Africa, Wang will visit Brazil and Jamaica from January 18 to 22, Mao said.
Experts said this year's visit to the four countries highlighted China's heightened attention to the security situation in North Africa against the background of a potential spillover of the Israeli-Palestinian conflict, as well as China's willingness to cooperate with African countries despite its level of development.
Mao noted that Wang's visit has carried on a fine tradition that has been kept for the past 34 years. The trip aims to promote the implementation of the outcomes of the Forum on China-Africa Cooperation (FOCAC) Leaders' Dialogue, and coordinate with African countries on a new session of FOCAC to be held this year.
At last year's FOCAC, Chinese President Xi Jinping proposed three new cooperation initiatives to support Africa's industrialization, agricultural modernization, and talent development, which received an enthusiastic response from his African counterparts, Mao said.
The tradition of the Chinese Foreign Minister's annual first trip to Africa has highlighted China's emphasis on consolidating friendship with Africa. The relationship sets an example of what can truly be called "the establishment of a community with a shared future," Song Wei, a professor from the School of International Relations at Beijing Foreign Studies University, told the Global Times on Thursday.
For the North Africa leg, the visit to Egypt highlights China's welcoming gesture to its officially joining the BRICS family. BRICS inducted five new countries in January and they are Saudi Arabia, the United Arab Emirates, Egypt, Iran, and Ethiopia.
Choosing to visit North Africa also reflects China's heightened concern over the security situation in the Middle East and the Red Sea, Song said.
As tensions in the region continue to grow, it has threatened the safe passage of an important lifeline for the international economy, and risks a conflict spillover. "The current situation is extremely dangerous from both a political and economic perspective," Song said. "At such a point, Wang's arrival brings the hope of coordinating relations among regional powers, trying to resolve conflicts and restore stability to the world economy and politics."
For West Africa, there were several instances of turmoil and conflicts last year, including military coups. And compared to other regions in Africa, West Africa faces more severe development challenges, so Wang's visit to this region highlighted China's emphasis on security and stability in the continent, experts said.
Cote d'Ivoire has relatively higher development levels in the continent, while Togo ranks as among one of the poorest countries in Africa, reflecting China's overall focus on Africa's development, Song noted.
Wang Youming, director of the Institute of Developing Countries at the China Institute of International Studies in Beijing, said China-Latin America relations have steadily progressed in the past few years, with a significant increase in trade volume, thanks to the structural advantage of a mutually beneficial economic complementarity.
Despite recent political changes in Latin America, with at least five general elections coming up this year including in Mexico and Uruguay, there will be little impact on China-Latin America relations whichever ruling party wins, whether left-wing or right-wing, Wang Youming told the Global Times on Thursday. This is because as an important trading partner, China plays a crucial role in helping them overcome economic challenges.
Zika virus may not be the black sheep of the family. Infections with either of two related viruses also cause fetal defects in mice, researchers find.
Some scientists have speculated that Zika’s capacity to harm a fetus might be unique among its kind, perhaps due to a recent change in the virus’s genetic material (SN: 10/28/17, p. 9). Others have argued that perhaps this dangerous ability was always there. It just wasn’t until the 2015–2016 epidemic in the Western Hemisphere that enough pregnant women were affected for public health researchers to identify the association with fetal defects (SN: 12/24/16, p. 19). But new work suggests this capacity is not Zika’s alone. Pregnant mice infected with West Nile or Powassan virus — both flaviviruses, like Zika — also showed fetal harm. Over 40 percent of these infected fetuses died. But among pregnant mice infected with one of two other mosquito-borne viruses unrelated to Zika, all of the fetuses survived, scientists report online January 31 in Science Translational Medicine.
The research underscores that “many viruses, including some similar to Zika, can infect the placenta and the cells of the baby,” says George Saade, an obstetrician-gynecologist and cell biologist at the University of Texas Medical Branch at Galveston. “This list keeps growing and highlights the risks from viruses that we are not very familiar with.”
Like Zika, West Nile virus and Powassan virus are neurotropic, meaning these pathogens target nerve cells. Both viruses can cause inflammation of the brain or of the membranes that surround the brain. West Nile is transmitted to humans by mosquitoes that have bitten infected birds. From 1999 to 2016, there were more than 46,000 cases reported to the U.S. Centers for Disease Control and Prevention. Powassan, spread by ticks who have fed on infected rodents, is less widespread; only 98 cases were reported from 2007 to 2016, mostly in the Northeast and Great Lakes area.
Jonathan Miner, a virologist at the Washington University School of Medicine in St. Louis, and his colleagues conducted some of the initial work in mice that demonstrated that Zika could harm fetuses (SN: 6/11/16, p. 15). The new study tests the effects of four other viruses: the two flaviviruses and two alphaviruses, chikungunya and Mayaro, which also have led to outbreaks in Zika-affected areas. The researchers infected 14 mice early in their pregnancies with one of the four viruses. By late pregnancy, 12 out of 30 fetuses from West Nile–infected mice had died, and half of the 16 fetuses from Powassan-infected mice had died. All of the fetuses from mice infected with chikungunya and Mayaro virus survived. West Nile virus and Powassan virus also replicated, or multiplied, more efficiently than the alphaviruses in lab samples of human placental tissue.
Zika, West Nile and Powassan share similarities in their genetic information, Miner says. “So there may be certain features of those virus genes and proteins in that particular family that confers this ability to infect certain cell types.” But scientists don’t understand fully what those features are yet, he says.
While this is the first study comparing the effects in mice of these mosquito-transmitted and tick-transmitted viruses in parallel, Miner says, past studies have raised the possibility of fetal infections with other flaviviruses besides Zika. A 2006 study of 77 pregnant women infected with West Nile virus reported that two had infants with microcephaly, the birth defect lately associated with Zika that results in unusually small and damaged brains.
In general, examining the potential effects of other flaviviruses on pregnant women and their developing fetuses is difficult, because outbreaks have been sporadic and less widespread than with Zika. It’s possible that cases in humans “could go largely unnoticed if we don’t look for them,” Miner says.
A new blood test might reveal whether someone is at risk of getting Alzheimer’s disease.
The test measures blood plasma levels of a sticky protein called amyloid-beta. This protein can start building up in the brains of Alzheimer’s patients decades before there’s any outward signs of the disease. Typically, it takes a brain scan or spinal tap to discover these A-beta clumps, or plaques, in the brain. But evidence is growing that A-beta levels in the blood can be used to predict whether or not a person has these brain plaques, researchers report online January 31 in Nature. These new results mirror those of a smaller 2017 study by a different team of scientists. “It’s a fantastic confirmation of the findings,” says Randall Bateman, an Alzheimer’s researcher at Washington University School of Medicine in St. Louis, who led the earlier study. “What this tells us is that we can move forward with this [test] approach with fairly high confidence that this is going to pan out.”
There’s currently no treatment for Alzheimer’s that can slow or stop the disease’s progression, so catching it early can’t currently improve a patient’s outcome. But a blood test could help researchers more easily identify people who might be good candidates for clinical trials of early interventions, says Steven Kiddle, a biostatistician at the University of Cambridge, who wasn’t part of either study.
Creating such a test has been challenging: Relatively little A-beta floats in the bloodstream compared with how much accumulates in the brain. And many past studies haven’t found a consistent correlation between the two.
In the new study, researchers used mass spectrometry, a more sensitive measuring technique than used in most previous tests, which allowed the detection of smaller amounts of the protein. And instead of looking at the total level of the protein in the blood, the team calculated the ratios between different types of A-beta, says coauthor Katsuhiko Yanagisawa, a gerontologist at the National Center for Geriatrics and Gerontology in Obu, Japan. He and his colleagues analyzed brain scans and blood samples from a group of 121 Japanese patients and a group of 252 Australian patients. Some participants had Alzheimer’s, some didn’t, and some had mild cognitive impairments that weren’t related to Alzheimer’s.
Using the ratios, the researchers found that they could discriminate between people who had A-beta plaques in the brain and those who didn’t. A composite biomarker score, created by combining two different ratios, predicted the presence or absence of A-beta plaques in the brain with about 90 percent accuracy in both groups of patients, the researchers found.
The new results are promising, Kiddle says, but the test still needs more refining before it can be used in the clinic. Another wild card: the cost. It’s still not clear whether the blood test will be more affordable than a brain scan or a spinal tap.
The 28-year-old space telescope, in orbit around the Earth, put itself to sleep on October 5 because of an undiagnosed problem with one of its steering wheels. But once more, astronomers are optimistic about Hubble’s chances of recovery. After all, it’s just the latest nail-biting moment in the history of a telescope that has defied all life-expectancy predictions.
There is one major difference this time. Hubble was designed to be repaired by astronauts on the space shuttle. Each time the telescope broke previously, a shuttle mission fixed it. “That we can’t do anymore, because there ain’t no shuttle,” says astronomer Helmut Jenkner of the Space Telescope Science Institute in Baltimore, who is Hubble’s deputy mission head. The most recent problem started when one of the three gyroscopes that control where the telescope points failed. That wasn’t surprising, says Hubble senior project scientist Jennifer Wiseman of NASA’s Goddard Space Flight Center in Greenbelt, Md. That particular gyroscope had been glitching for about a year. But when the team turned on a backup gyroscope, it didn’t function properly either.
Astronomers are working to figure out what went wrong and how to fix it from the ground. The mood is upbeat, Wiseman says. But even if the gyroscope doesn’t come back online, there are ways to point Hubble and continue observing with as few as one gyroscope.
“This is not a catastrophic failure, but it is a sign of mortality,” says astronomer Robert Kirshner of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. Like cataracts, he says, it’s “a sign of aging, but there’s a very good remedy.” While we wait for news of how Hubble is faring, here’s a look back at some of its previous hiccups and repair missions.
1990: The blurry mirror On June 27, 1990, three months after the space telescope launched, astronomers discovered an aberration in Hubble’s primary mirror. Its curvature was off by two micrometers, making the images slightly blurry.
The telescope soldiered on, despite being the butt of jokes on late-night TV. It observed a supernova that exploded in 1987 (SN: 2/18/17, p. 20), measured the distance to a satellite galaxy of the Milky Way and took its first look at Jupiter before the space shuttle Endeavour arrived to fix the mirror in December 1993. 1999: The first gyroscope crisis On November 13, 1999, Hubble was put into safe mode after the fourth of its six gyroscopes failed, leaving it without the three working gyros necessary to point precisely. An already planned preventative maintenance shuttle mission suddenly became more urgent. NASA split the mission into two parts to get to the telescope more quickly. The first part became a rescue mission: Astronauts flew the space shuttle Discovery to Hubble that December to install all new gyroscopes and a new computer.
2004: Final shuttle mission canceled After the space shuttle Columbia disintegrated while re-entering Earth’s atmosphere in 2003, NASA canceled the planned fifth and final Hubble reservicing mission. “That could really have been the beginning of the end,” Jenkner says.
The team has known for more than a decade that someday Hubble will have to work with fewer than three gyroscopes. To prepare, Hubble’s operations team deliberately shut down one of the telescope’s gyroscopes in 2005, to observe with only two.
“We’ve been thinking about this possibility for many years,” Wiseman says. “This time will come at some point in Hubble’s mission, either now or later.”
Shutting down the third gyroscope was expected to extend Hubble’s life by only eight months, until mid-2008. In the meantime, two of the telescope’s scientific instruments — the Space Telescope Imaging Spectrograph and the Advanced Camera for Surveys — stopped working due to power supply failures. 2009: New lease on life Fortunately, NASA restored the final servicing mission, and the space shuttle Atlantis visited Hubble in May 2009 (SN Online: 5/11/09). That mission restored Hubble’s cameras, installed new ones and crucially, left the space telescope with six new gyroscopes, three for immediate use and three backups. The three gyroscopes still in operation (including the backup that is currently malfunctioning) are of a newer type, and are expected to live five times as long as the older ones, which last four to six years.
The team expects Hubble to continue doing science well into the 2020s and to have years of overlap with its successor, the James Webb Space Telescope, due to launch in 2021. “We are always worried,” says Jenkner, who has been working on Hubble since 1983. “At the same time, we are confident that we will be running for quite some time more.”
Call it an October surprise: Hurricane Michael strengthened unusually quickly before slamming into the Florida panhandle on October 10 and remained abnormally strong as it swept into Georgia. The storm made landfall with sustained winds of about 250 kilometers per hour, just shy of a category 5 storm, making it the strongest storm ever to hit the region, according to the National Oceanographic and Atmospheric Administration’s National Hurricane Center, or NHC.
Warm ocean waters are known to fuel hurricanes’ fury by adding heat and moisture; the drier air over land masses, by contrast, can help strip storms of strength. So hurricanes nearing the Florida panhandle, a curving landmass surrounding the northeastern Gulf of Mexico, tend to weaken as they pull in drier air from land. But waters in the Gulf that were about 1 degree to 2 degrees Celsius warmer than average for this time of year, as well as abundant moisture in the air over the eastern United States, helped to supercharge Michael. Despite some wind conditions that scientists expected to weaken the storm, it strengthened steadily until it made landfall, which the NHC noted “defies traditional logic.” The fast-moving storm weakened only slightly, to a category 3, before hurtling into Georgia. Although it is not possible to attribute the generation of any one storm to climate change, scientists have long predicted that warming ocean waters would lead to more intense tropical cyclones in the future. More recent attribution studies have borne out that prediction, suggesting that very warm waters in the tropical Atlantic helped to fuel 2017’s powerful storm season, which spawned hurricanes Irma and Maria.
Hurricane Harvey, fueled by unusually warm waters in the Gulf of Mexico in August 2017, also underwent a rapid intensification, strengthening from a tropical storm to a category 4 hurricane within about 30 hours. And this year, scientists reported that Hurricane Florence, which slammed into the Carolinas in September, was probably warmer and wetter due to warmer than average sea surface temperatures in the Atlantic Ocean.
We may truly be led by our noses. A sense of smell and a sense of navigation are linked in our brains, scientists propose.
Neuroscientist Louisa Dahmani and colleagues asked 57 young people to navigate through a virtual town on a computer screen before being tested on how well they could get from one spot to another. The same young people’s smelling abilities were also scrutinized. After a sniff of one of 40 odor-infused felt-tip pens, participants were shown four words on a screen and asked to choose the one that matched the smell. On these two seemingly different tasks, the superior smellers and the superior navigators turned out to be one and the same, the team found.
Scientists linked both skills to certain spots in the brain: The left orbitofrontal cortex and the right hippocampus were both bigger in the better smellers and better navigators. While the orbitofrontal cortex has been tied to smelling, the hippocampus is known to be involved in both smelling and navigation. A separate group of nine people who had damaged orbitofrontal cortices had more trouble with navigation and smell identification, the researchers report October 16 in Nature Communications. Dahmani, who’s now at Harvard University, did the work while she was at McGill University in Montreal.
A sense of smell may have evolved to help people find their way around, an idea called the olfactory spatial hypothesis. More specific aspects of smell, such as how good people are at detecting faint whiffs, could also be tied to navigation, the researchers suggest.
Climate change may be flipping good Arctic neighborhoods into killing fields for baby birds.
Every year, shorebirds migrate thousands of kilometers from their southern winter refuges to reach Arctic breeding grounds. But what was once a safer region for birds that nest on the ground now has higher risks from predators than nesting in the tropics, says Vojtěch Kubelka, an evolutionary ecologist and ornithologist at Charles University in Prague. With many shorebird populations dwindling, nest success matters more every year. A longtime fan of shorebirds, Kubelka had heard about regional tests of how predator risk changes by latitude for bird nests. He, however, wanted to go global. Shorebirds make a great group for such a large-scale comparison, he says, because there’s not a lot of variation in how nests look to predators. A feral dog in the United States and a fox in Russia are both creeping up on some variation of a slight depression in the ground. So Kubelka and his colleagues crunched data from decades of records of predator attack rates on about 38,000 nests of various sandpipers, plovers and other shorebirds. After a massive literature search, the study zeroed in on the experiences of 237 populations of a total of 111 shorebird species at 149 places on six continents. It’s the first attempt at a global comparison by latitude of predator attack rates on shorebird nests over time, he says.
Historical data of predator attack rates worldwide averaged about 43 percent before 1999, but has since reached 57 percent, the team reports in the Nov. 9 Science. The most dramatic upward swoop came from the Arctic nest reports. There, the rate of predator attacks averaged around 40 percent in the last century, jumping to about 65 or 70 percent since 1999. Meanwhile, tropical perils in the Northern Hemisphere changed “only modestly” the researchers say, from around 50 percent to about 55 percent. Researchers also looked at how much, and how erratically, temperatures had changed at each site. Overall, the growing dangers to nests fit with climate change trends. Biologists have discussed the idea that nest predation generally lessens when birds move out of the tropics. One advantage of migrating toward the pole to breed was, in theory, to escape from tropical abundance of snakes, rodents and other egg-lovers.
But rapid warming in the Arctic might have discombobulated some of the old predator-prey relationships, says coauthor Tamás Székely, a conservation biologist at the University of Bath in England. For instance, Arctic foxes used to get much of their nourishment from lemmings, voles and other small rodents. Skimpy snow cover in warmer winters, however, doesn’t insulate little rodents as well as it used to. Boom-and-bust cycles of lemming populations are in many places now “mostly bust,” he says. Foxes and other predators may be shifting more to bird eggs and nestlings.
That scenario of rodent-loving predators hunting more birds sounds “highly probable,” but may be just part of what’s going on, says Dominique Fauteux, an ecologist at the Canadian Museum of Nature in Ottawa who studies small mammals. Lemming collapses haven’t been reported across the whole Canadian Arctic, he says.
Instead, some researchers have proposed that shorebird nest failures come from a boom in geese that attract more bird predators overall. Also, a 2010 study suggests that nest predation in the Canadian Arctic was still lower than in temperate areas. There may be some global pattern, but on the ground, Fauteux says, “there clearly are nuances.”
In a broad swath of northwestern Alaska, small groups of recent immigrants are hard at work. Like many residents of this remote area, they’re living off the land. But these industrious foreigners are neither prospecting for gold nor trapping animals for their pelts. In fact, their own luxurious fur was once a hot commodity. Say hello to Castor canadensis, the American beaver.
Much like humans, beavers can have an oversized effect on the landscape (SN: 8/4/18, p. 28). People who live near beaver habitat complain of downed trees and flooded land. But in areas populated mostly by critters, the effects can be positive. Beaver dams broaden and deepen small streams, forming new ponds and warming up local waters. Those beaver-built enhancements create or expand habitats hospitable to many other species — one of the main reasons that researchers refer to beavers as ecosystem engineers. Beavers’ tireless toils — to erect lodges that provide a measure of security against land-based predators and to build a larder of limbs, bark and other vegetation to tide them over until spring thaw — benefit the wildlife community.
A couple of decades ago, the dam-building rodents were hard to find in northwestern Alaska. “There’s a lot of beaver around here now, a lot of lodges and dams,” says Robert Kirk, a long-time resident of Noatak, Alaska — ground zero for much of the recent beaver expansion. His village of less than 600 people is the only human population center in the Noatak River watershed. Beavers may be infiltrating the region for the first time in recent history as climate change makes conditions more hospitable, says Ken Tape, an ecologist at the University of Alaska Fairbanks. Or maybe the expansion is a rebound after trapping reduced beaver numbers to imperceptible levels in the early 1900s, he says. Nobody knows for sure. And the full range of changes the rodents are generating in their new Arctic ecosystems hasn’t been studied in detail. But from what Tape and a few other researchers can tell so far, the effects could be profound, and most of them will probably be beneficial for other species.
In the areas newly colonized by beavers, “some really interesting processes are unfolding,” says John Benson, a wildlife ecologist at the University of Nebraska–Lincoln who studies wolves and coyotes, among other beaver predators. “I’d expect some pretty dramatic changes to the areas they take over.”
Beavers’ biggest effects on Arctic ecosystems may come from the added biodiversity within the ponds they create, says James Roth, an ecologist at the University of Manitoba in Winnipeg, Canada. These “oases on the tundra” will not only provide permanent habitat for fish and amphibians, they’ll serve as seasonal stopover spots for migratory waterfowl. Physical changes to the environment could be just as dramatic, thawing permafrost decades faster than climate change alone would.
The Arctic tundra isn’t the first place beavers have made their mark. Changes seen in beaver-rich areas at lower latitudes may offer some clues to the future of the Alaskan tundra, home to moose, caribou and snowshoe hares.
North through Alaska As Earth’s climate has warmed in recent years, some plants and animals — such as the mountain-dwelling pika, a small mammal related to rabbits — have fled the heat by moving to higher altitudes (SN: 6/30/12, p. 16). Others, from moose and snowshoe hares to bull sharks and bottlenosed dolphins, have moved toward the poles to take advantage of newly hospitable ecosystems (SN: 5/26/18, p. 9).
Arctic environments have changed more than most, Tape says. Polar regions are warming much faster than other parts of the world, he says. Studies estimate that average temperatures in the Arctic have risen about 1.8 degrees Celsius since 1900, about 60 percent faster than the Northern Hemisphere as a whole.
This warming is bringing great change to the Alaskan tundra, Tape says. Winter snow cover doesn’t persist as long as it used to. Streams freeze later in the fall and melt earlier in the spring. Permafrost, the perennially frozen ground, is thawing, allowing shrubs to take hold. New species are moving in, few more noticeable than the beaver. The dams they build and the ponds they create are hard to miss; these newly formed bodies of water even show up on satellite images. Beavers have infiltrated three watersheds in northwestern Alaska in the last couple of decades. Together these drainages cover more than 18,000 square kilometers — an area larger than Connecticut.
On images of the region collected by Landsat satellites in summer months from 1999 through 2014, Tape and colleagues looked for new areas of wetness that covered at least half a hectare (1.24 acres), or about four times the area covered by an Olympic swimming pool.
The researchers then used newer, high-resolution satellite images to verify the presence of beaver ponds. Available aerial photographs taken before 1999 didn’t pick up any signs of beaver activity in the area, Tape says. Kirk notes that beavers were present in the Lower Noatak River watershed before 1999, but in vastly smaller numbers than they are today.
Based on the images at hand, the researchers found 56 new complexes of beaver ponds in the area over the 16-year study period. On average, beavers expanded their range about 8 kilometers per year, Tape and colleagues reported in the October Global Change Biology.
“This is remarkable, but it shouldn’t come as a surprise,” Tape says. “Beavers are engineers that work every day, all summer long.”
The animals have also made their way into western Alaska’s Seward Peninsula and the northern foothills of the Brooks Range, mountains that stretch east to west across northern Alaska, the researchers found. If the animals’ recent rate of expansion continues, beavers could spread throughout Alaska’s North Slope in the next 20 to 40 years, the researchers say. The Lower Noatak River watershed, one of the areas that Tape and colleagues studied, is mostly tundra. By definition that means treeless plain. But the area also is about 3.5 percent forest, mainly concentrated along the river and its tributaries. The watersheds just to the north are completely tundra. So how do the beavers there build dams without trees? In those areas, Tape says, the animals construct smaller dams than they might at lower latitudes, using the branches, twigs and foliage of willows and other shrubs.
“I never expected to see beavers on the tundra,” Roth says, intrigued by Tape’s team’s findings.
Happy place The beavers are not only persisting on the tundra, they’re thriving. The moderately sized streams and flat terrain provide ideal habitat. And once they gain a foothold, these industrious creatures set about making improvements that are probably an overall plus for myriad other species, Tape says.
For instance, frigid conditions in the region cause shallow streams to freeze solid in winter. But when a beaver builds a dam, the water that gathers upstream of the structure becomes deep enough to remain liquid below a sheet of ice that provides insulation from the chilly winter air.
That persistent liquid lets the beavers move about under the ice even in the depths of winter. The water gives them a place to stockpile food, too, Tape notes. That constant supply of liquid water also provides year-round habitat for fish, amphibians and even some insects in their larval stages. None of these species are part of the beaver’s diet, but they could serve as food for other creatures. “All that diversity would add whole new layers to food webs,” Roth says. Ecological changes could extend well beyond the beaver pond. The water impounded by beaver dams sometimes finds its way past the dam, Tape says. The satellite photos that he and his colleagues analyzed revealed that some stretches of river just downstream of beaver dams now remain unfrozen even in winter. That flowing water probably spills over the dam or around its edges, but some may seep through or under the structure.
That liquid water also helps thaw the underlying permafrost. Previous studies have shown that even a shallow pond less than a meter deep can boost sediment temperature by as much as 10 degrees C above the locale’s average air temperature. That kind of warming causes permafrost to thaw decades earlier than it would without the pond. Although scientists are concerned that permafrost thawing will release stored carbon into the atmosphere, no one yet knows how that thawing will affect the balance of carbon emissions to the atmosphere (SN: 1/21/17, p. 15).
Field studies at lower latitudes hint that beavers will probably bring about other ecological changes, too, Tape says, which might shift over time. For example, moose and snowshoe hares eat the same willow shrubs that beavers consume and build their dams with. And ptarmigan, a crow-sized bird in the grouse family, rely on those shrubs for cover, especially during winter. So immediately after beavers move into an area and start clearing that brush, populations of those species may decline.
But the long-term benefits will probably outweigh the short-term impacts on those species, says Matthew Mumma, an ecologist at the University of Northern British Columbia in Prince George, Canada. Permafrost that thaws along the fringe of a beaver pond will probably boost numbers of the shrubs that these species depend on, Tape and colleagues suggest. So in the long run, the overall numbers of moose, hares and ptarmigan may rise. Likewise, Mumma notes, beavers could provide big benefits for salmon and other migratory fish. Beaver dams were once thought to impede the travel of such fish upstream or to reduce the number of places where fish could spawn. But studies in the western United States, among other places, have suggested that the presence of beavers actually helps boost populations of salmon. For instance, the aquatic grasses in beaver ponds offer hiding places for young fish. Also, the languid ponds provide a resting spot for adult fish migrating upstream to spawning sites.
Better-fed wolves Boosting herbivore populations on the tundra would be a boon for local predators, of course. Larger numbers of snowshoe hares, for example, could feed the populations of the arctic foxes that prey upon them, Mumma says. And more moose could mean better-fed wolves.
Beavers themselves make a meal for bears, wolverines and wolves. In areas where wolves and beavers coexist, the rodents make up as much as 30 percent of the wolf diet, Roth says. The presence of a more reliable and more diversified food supply could lead wolves to settle down in smaller territories rather than migrating widely.
Benson and his team have already seen the impact of beaver populations on wolves, coyotes and wolf-coyote hybrids in Ontario’s Algonquin Provincial Park from August 2002 until April 2011.
In that time, 37 of the 105 pups that had been tagged with radio transmitters died, Benson says. The second-highest cause of death was starvation. Every one of those starvation-related deaths took place in the western portion of the park, which has relatively rugged terrain and few beavers. In the eastern portion of the park, where beavers are plentiful, none of the pups starved, Benson and his team reported in 2013 in Biological Conservation. In a separate study, Mumma and colleagues analyzed aerial surveys of beaver populations within seven broad regions in northeastern British Columbia in 2011 and 2012. Proximity to human activity, such as roadbuilding or oil and gas exploration, didn’t seem to affect beavers’ decisions to build at a particular locale. Nor did the presence of wolves in the area, the researchers reported in February in the Canadian Journal of Zoology.
Although having wolves nearby seemed to affect the number of beavers present (quite possibly via consumption), the predators didn’t seem to scare the rodents away entirely, Mumma notes.
More beavers, fewer sick moose Whether the presence of beavers on the Alaskan tundra ends up boosting the numbers of moose and other ungulates, the dam builders could have a big, though indirect, impact on the hoofed browsers’ health.
Roth and parasitologist Olwyn Friesen, now at the University of Otago in Dunedin, New Zealand, recently studied how a wolf’s diet affects the parasites it carries — which can then be passed on to other creatures in the environment. The researchers analyzed 32 wolf carcasses collected by provincial conservation officers in southeastern Manitoba in 2011 and 2012. Those remains came from hunters, trappers and roadkill.
In particular, the team tallied the parasites in the wolves’ lungs, liver, heart and intestines. The group also measured the ratio of carbon-12 and carbon-13 isotopes in the wolf tissues, which provided insight into what sorts of prey each individual wolf had eaten near the time those tissues formed.
Typical prey for wolves in this area are, from most consumed to least: white-tailed deer, snowshoe hare, moose, beaver and caribou, Roth says. Each of these creatures has a distinct ratio of the two carbon isotopes in its tissues. That ratio gets passed along to the predators that eat them.
The wolves with diets heavier in beaver had, on average, fewer intestinal parasites called cestodes. (Tapeworms are the best-known members of that group.)
The implications are clear, Roth and Friesen reported in 2016 in the Journal of Animal Ecology. Beaver-eating wolves are much less likely to excrete parasites into the environment where they could be picked up by ungulates, such as moose and caribou. Wolves don’t seem to be detrimentally affected by such parasites. But ungulates that become infected — especially older animals — may have reduced lung capacity, making escape from predators more difficult. A new resource Although beavers may speed changes in the Arctic, those effects may still take a long time to manifest.
Despite the proliferation of beavers in the Lower Noatak River watershed in the last couple of decades, “things around here grow so slowly, they’re not really having a long-term impact yet,” says local resident Kirk. Shrubs haven’t yet noticeably spread into any areas of permafrost that have been thawed by waters impounded by recent dam-building.
Nor have the beavers made much of a mark on the local economy, he says. “There’s a lot of people harvesting them now, since there’s so many of them around,” he adds. However, the pelts from those rodents are so far used by the trappers themselves, not sold to others.
The beavers haven’t become a big draw on the local food scene, either. Even connoisseurs say the meat has a gamey, greasy taste. As Kirk puts it, “we haven’t adjusted our taste buds to them yet.”
A new type of implantable bandage could help mend broken hearts.
Each bandage is a thin film that oozes a cocktail of molecules to heal tissue damaged during a heart attack. In experiments with rats and pigs, these patches helped minimize scarring and preserve the heart’s ability to pump blood, researchers report online November 28 in Science Advances. Such devices could someday curb heart attack survivors’ risk of heart failure.
The base of each heart-healing film is a polymer sheet studded with tiny needles — similar to other microneedle patches that deliver vaccines but designed to stick to a patient’s heart rather than her skin (SN: 8/5/17, p. 8). The surface of the polymer opposite the array of microneedles is coated in a gel containing cardiac stromal cells. These cells secrete molecules, such as proteins and tiny pieces of genetic material known as microRNAs, that support the growth of heart muscle cells. “We’re treating [the patch cells] as little pharmacies,” says study coauthor Ke Cheng, a biological engineer at North Carolina State University in Raleigh. When a patch is attached to the heart, the microneedles funnel curative molecules from the cardiac stromal cells directly into the damaged tissue.
In rats, Cheng’s team tested how well the microneedle patches promoted healthy tissue growth and mitigated scarring. Three weeks after researchers induced rats to have heart attacks, the animals with microneedle patches had roughly 40 percent healthy tissue in the regions of their hearts affected by the heart attack, whereas as untreated rats had only about 10 percent. For the pigs, the researchers tracked heart health by measuring how much blood was pumped from the animal’s left ventricle to the rest of its body with each heartbeat. Four hours after a heart attack, each heartbeat released about 56 to 57 percent of all the blood in the left ventricle, in both treated and untreated pigs. But 48 hours after the attack, the results began to diverge: Hearts treated with microneedle patches pumped about 60 percent of the left ventricle’s volume, while untreated hearts pumped about 50 percent. The new microneedle design “is a very interesting and exciting” idea, but researchers need to investigate how animals implanted with these patches fare over longer periods, says Tamer Mohamed, a cardiovascular researcher at the University of Louisville in Kentucky not involved in the work. Before these microneedle patches are used to treat humans, Cheng’s team plans to swap out the polymer used in this study for a material that gradually dissolves inside the body. The researchers are also exploring less invasive ways to implant patches than open-heart surgery, Cheng says.
When most people were thinking about summer vacation, we were contemplating the biggest science stories of 2018.
Yep, it takes more than six months of effort to put together Science News’ annual issue on the Top 10 science stories of the year. 2018 was no different, though we were hit with some exciting twists that had us revisiting our decisions just a week or so before closing the issue.
The early discussions tend to be more about themes — climate emerged as a big one, even before the recent reports linking increased severity of hurricanes, floods and wildfires to climate change. Reporters lobby to get the stories that intrigued them the most or the discoveries that mark critical turning points onto the short list. By August, our editors have identified contenders for the top of the list and are assigning stories so writers can get to work. We try to keep the choices under wraps; it’s part of the fun. All of the stories are assigned by October 1. By then, we’re also planning illustrations, graphics and bonus items, like our much-loved list of favorite science books of the year. By Thanksgiving, we’ve nailed down the “map” for the magazine, including story order and page designs.
And then news happens. This year was particularly rich in breaking news that had us reshuffling the deck. That included the discovery of an impact crater hidden under Greenland’s ice, which some scientists argue contributed to the die-off of the mammoths. That story broke on November 14 (SN: 12/8/18, p. 6).
Then there was the U.S. report on domestic climate change impacts, which was released the Friday after Thanksgiving. A few days later came an even bigger surprise: A Chinese scientist claimed that he had created the world’s first gene-edited babies. The announcement unleashed a torrent of criticism from scientists around the world. So what would you pick as the No. 1 science story of the year? After much discussion, our editorial team decided to stick with our original choice of climate change, considering the extraordinary amount of new data released this year and the import of those findings. The Chinese babies elbowed their way into the No. 2 slot. Even though the scientist’s claim may prove false, the technology has clearly advanced to the point where scientists and governments must act to set ethical standards for human gene editing.
Note to our readers: The magazine will be taking a break over the holidays. The next issue you receive will be dated January 19. But we’ll still be hard at work reporting on developments in science, medicine and technology; visit us at www.sciencenews.org for the latest. In 2019, we’ll publish four double issues, in May, July, October and December. These special issues include more features and in-depth coverage of topics like last summer’s “Water woes,” which included reporting from Mumbai, India. We love having the opportunity to dig deep on pressing issues and hope you enjoy the results. Thank you for being part of the Science News community. We wish you joyous holidays and an evidence-based new year.
