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Towering fire-fueled thunderclouds can spew as many aerosols as volcanic eruptions
A massive plume of smoke lofted into the stratosphere during Australia’s fires may represent a new class of “volcanic-scale” pyrocumulonimbus clouds. More
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Plastic waste forms huge, deadly masses in camel guts
Marcus Eriksen was studying plastic pollution in the Arabian Gulf when he met camel expert Ulrich Wernery. “[Ulrich] said, ‘You want to see plastic? Come with me.’ So we went deep into the desert,” Eriksen recalls. Before long, they spotted a camel skeleton and began to dig through sand and bones.
“We unearthed this mass of plastic, and I was just appalled. I couldn’t believe that — almost did not believe that — a mass as big as a medium-sized suitcase, all plastic bags, could be inside the rib cage of this [camel] carcass,” says Eriksen, an environmental scientist at the 5 Gyres Institute, a plastic pollution research and education organization in Santa Monica, Calif.
“We hear about marine mammals, sea lions, whales, turtles and seabirds impacted” by plastic waste, Eriksen says (SN: 6/6/19). But “this is not just an ocean issue. It’s a land issue, too. It’s everywhere.”
About 390,000 dromedary camels (Camelus dromedarius) live in the United Arab Emirates. Now in a study in the February 2021 Journal of Arid Environments, Eriksen, Wernery and colleagues estimate that plastic kills around 1 percent of these culturally important animals.
Of 30,000 dead camels that Wernery, a veterinary microbiologist at the Central Veterinary Research Laboratory in Dubai, and his team have examined since 2008, 300 had guts packed with plastic ranging from three to 64 kilograms. The researchers dubbed these plastic masses “polybezoars” to distinguish them from naturally occurring hair and plant fiber bezoars.
When camels eat plastic, it accumulates into enormous, stomach-clogging masses called polybezoars. Researchers found these polybezoars — the biggest of which weighs almost 64 kilograms — inside dead camels in the desert near Dubai.M. Eriksen et al/J. Arid Enviro. 2021
When camels eat plastic, it accumulates into enormous, stomach-clogging masses called polybezoars. Researchers found these polybezoars — the biggest of which weighs almost 64 kilograms — inside dead camels in the desert near Dubai.M. Eriksen et al/J. Arid Enviro. 2021
As dromedaries roam the desert looking for food, they munch on plastic bags and other trash that drift into trees and pile up along roadsides. “From the camel’s perspective … if it’s not sand, it’s food,” Eriksen says.
With a stomach full of plastic, camels don’t eat because they don’t feel hungry, and they starve to death. Plastic can also leach toxins and introduce bacteria that poison the one-humped mammals, Wernery says.Sign Up For the Latest from Science News
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“If 1 percent mortality due to plastic is verified by future and more detailed studies, then plastic pollution will certainly represent a reason of concern for [camels],” says Luca Nizzetto, an environmental scientist at the Norwegian Institute for Water Research in Oslo, who was not involved with the research. “These types of studies are relevant to raise social awareness about this pollution.”
Banning plastic bags and single-use plastics is crucial for protecting camels and other wildlife, Eriksen says. “Plastic bags are escape artists. They blow out of garbage cans, out of landfills, out of trucks and out of people’s hands. They travel for hundreds of miles.” More - in Heart
In the past 15 years, climate change has transformed the Arctic
Fifteen years of grading warming’s impact on the Arctic has made one thing abundantly clear: Climate change has drastically altered the Arctic in that short time period.
Breaking unfortunate records is “like whack-a-mole,” says Jackie Richter-Menge, a climate scientist at the University of Alaska Fairbanks and an editor of the 2020 Arctic Report Card, released December 8 at the virtual meeting of the American Geophysical Union. From sea ice lows to temperature highs, records keep popping up all over the place. For instance, in June, a record-high 38° Celsius (100.4° Fahrenheit) temperature was recorded in the Arctic Circle (SN:6/23/20). And in 2018, winter ice on the Bering Sea shrank to a 5,500 year low (SN:9/3/20).
“But quite honestly, the biggest headline is the persistence and robustness of the warming,” Richter-Menge says. In 2007, only a year after the first Arctic Report Card, summer sea ice reached a record low, shrinking to an area 1.6 million square kilometers smaller than the previous year. Then, only five years later, the report card noted a new low, 18 percent below 2007. In 2020, sea ice didn’t set a record but not for lack of trying: It still was the second lowest on record in the last 42 years.
“The transformation of the Arctic to a warmer, less frozen and biologically changed region is well under way,” the report concludes. And it’s changing faster than expected when researchers launched the report card in 2006. The annual average air temperature in the Arctic is rising two to three times faster than the rest of the globe, Richter-Menge says. Over the last 20 years, it’s warmed at a rate of 0.77 degrees C per decade, compared with the global average of 0.29 degrees C per decade.Sign Up For the Latest from Science News
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Improvements in research techniques over the last 15 years have helped researchers more thoroughly observe warming’s impact and how different aspects of Arctic climate change are linked to one another, she says. These improvements include the ability to measure ice mass via gravity measurements taken by the Gravity Recovery and Climate Experiment (GRACE) satellite. Other satellites have provided additional observations from above while on-the-ground measurements, such as by the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC), have provided up-close sea ice measurements (SN:4/8/20). The report has also begun to include on-the-ground observations of the Arctic’s Indigenous people, who experiences these changes directly (SN:12/11/19).
The changes have revealed few bright spots but one is the rebound of bowhead whales, which were hunted almost to extinction around the turn of the 20th century. While researchers are careful to note that the whales are still vulnerable, the four populations of the whales (Balaena mysticetus) now range from 218 in the Okhotsk Sea to around 16,800 in the Bering, Chukchi and Beaufort seas. Researchers suggest that the whales’ rebound is due, at least in part, to the warming that has occurred over the last 30 years. Earlier sea ice melting and warmer surface water means more krill and other food for these baleen feeders.
In a rare bit of good news from the Arctic, researchers report that bowhead whales are on the rebound. Unfortunately, the same warming that has aided the whales has melted ice sheets and increased hardships for Indigenous hunters.Nature Picture Library/Alamy Stock Photo
But don’t be fooled. The potential good news is overshadowed by the bad news. There’s been “this accumulation of knowledge and insights that we’ve gained over 15 years,” says Mark Serreze, a climate scientist at the National Snow and Ice Data Center in Boulder, Colo., who wasn’t involved in this year’s report. The 2020 research is “an exclamation point on the changes that have been unfolding,” he says. “The bowhead whales are doing OK, but that’s about it.” More - in Heart
Ancient people may have survived desert droughts by melting ice in lava tubes
Bands of charcoal from fires lit long ago, found in an ice core from a New Mexico cave, correspond to five periods of drought over 800 years. More
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Ancient humans may have deliberately voyaged to Japan’s Ryukyu Islands
Long ago, ancient mariners successfully navigated a perilous ocean journey to arrive at Japan’s Ryukyu Islands, a new study suggests.
Archaeological sites on six of these isles — part of a 1,200-kilometer-long chain — indicate that migrations to the islands occurred 35,000 to 30,000 years ago, both from the south via Taiwan and from the north via the Japanese island of Kyushu.
But whether ancient humans navigated there on purpose or drifted there by accident on the Kuroshio ocean current, one of the world’s largest and strongest currents, is unclear. The answer to that question could shed light on the proficiency of these Stone Age humans as mariners and their mental capabilities overall.
Now, satellite-tracked buoys that simulated wayward rafts suggest that there’s little chance that the seafarers reached the isles by accident.Sign Up For the Latest from Science News
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Researchers analyzed 138 buoys that were released near or passed by Taiwan and the Philippine island Luzon from 1989 to 2017, deployed as part of the Global Drifter Program to map surface ocean currents worldwide. In findings published online December 3 in Scientific Reports, the team found that only four of the buoys came within 20 kilometers of any of the Ryukyu Islands, and these did so only as a result of typhoons and other adverse weather.
It is unlikely that ancient mariners would have set out on an ocean voyage with a major storm on the horizon, say paleoanthropologist Yousuke Kaifu of the University of Tokyo and colleagues. As a result, the new findings indicate that the Kuroshio current would have forced drifters away from rather than toward the Ryukyu Islands, suggesting that anyone who made the crossing did so intentionally instead of accidentally, Kaifu says.
Geologic records suggest that currents in the region have remained stable for at least the past 100,000 years. So it’s reasonable to conclude that these buoys mimic how well ancient watercraft set adrift in the same area might have fared, the researchers say.
“From a navigation perspective, crossing to the Ryukyus was so challenging that accidental-drift models are unlikely to provide an effective explanation,” agrees archaeologist Thomas Leppard of Florida State University in Tallahassee, who was not involved in the research. This new work “is, of course, not conclusive, but it is suggestive.”
Stone tools and butchered remains of a rhinoceros suggest archaic human lineages such as Homo erectus may have similarly crossed seas at least 709,000 years ago. And artifacts found in Australia suggest modern humans may have begun voyaging across the ocean at least 65,000 years ago (SN: 7/19/17). But it remains hotly debated whether humans’ ocean journeys during the Paleolithic, which lasted from roughly 2.6 million years ago to about 11,700 years ago, were generally made accidentally or intentionally.
Other data do suggest that ancient humans could have deliberately made the voyage to the Ryukyu Islands. In 2019, a team of adventurers succeeded in paddling more than 200 kilometers from Taiwan to Yonaguni in the archipelago using a dugout canoe that Kaifu and his colleagues made using stone axes modeled off Japanese Paleolithic artifacts.
Although the people of the Paleolithic are often perceived as primitive and conservative in their goals, “I feel something very different from the evidence of human presence on these remote islands,” Kaifu says. More - in Heart
Plastics are showing up in the world’s most remote places, including Mount Everest
Minuscule shreds and threads of plastic are turning up all over, including in the snow on Mount Everest.
“We’ve known that plastic is in the deep sea, and now it’s on the tallest mountain on Earth,” says Imogen Napper, a marine scientist at the University of Plymouth in England and a National Geographic Explorer. “It’s ubiquitous through our whole environment.”
Plastic plays an increasingly large role in our lifestyles: Globally, the use of plastics has shot up from around 5 million metric tons in the 1950s to more than 330 million metric tons in 2020. As they’re used and cast away, these plastic products shed tiny particles. The broken-down bits of bags, bottles and other consumer plastics, each smaller than 5 millimeters, can harm animals, such as marine crabs that get plastics stuck in their gills (SN: 7/8/14). They may also mess with ecosystems (SN: 1/31/20).
Here are some of the most extreme places where microplastics have been found.Sign Up For the Latest from Science News
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Atop the world’s tallest mountain
All of the 11 snow samples that Napper’s team analyzed from Mount Everest contained plastic, the researchers report November 20 in One Earth. “I had no idea what the results were going to look like … so that really took me aback,” says Napper.
The highest concentration of microplastics — 119,000 pieces per cubic meter — was in snow from Everest Base Camp, where climbers congregate, but plastic pieces also appeared at a spot 8,440 meters above sea level, near the 8,850-meter summit. The scientists also found plastics in three of eight samples of stream water from Everest. Perhaps the finding should not have been so surprising: Hundreds of people attempt to summit the mountain each year, leaving piles of trash behind. The majority of the microplastics found were polyester fibers, likely originating from climbers’ equipment and clothes.
In the deepest ocean depths
Plastic pollution in the sea goes far deeper than the floating Pacific garbage patch (SN: 3/22/18). Scientists have fished plastic fibers and fragments from the guts of critters dwelling in ocean trenches around the Pacific Rim. Of 90 crustaceans analyzed in a 2019 study, 65 contained microplastics, with the deepest coming from 10,890 meters down in the Mariana Trench. In another study, a sampling of water in the Monterey Bay suggests that plastic debris is accumulating below the surface and is most prevalent at 200 to 600 meters deep (SN: 6/6/19).
Animals are ingesting microplastics in the deepest parts of the sea. In the guts of amphipods (one shown, left) collected from nine sites on the Pacific Rim’s trenches, researchers found plastic fragments, including microfibers (right) found in a critter from 10,890 meters deep in the Mariana Trench.A.J. Jamieson et al/Roy Soc Open Society 2019
Blowing in the wind
Carried through the air, microplastics can make their way to remote areas such as a meteorological station in the Pyrenees Mountains (SN: 4/15/19). On average, an estimated 365 microplastic particles per square meter per day rained down on that site during the study period, about as much as falls from the sky in some cities. Simulations of wind directions and speed suggest the plastic fragments traveled at least 95 kilometers before landing at the site.
Embedded in Arctic ice
A 2018 study reported millions to tens of millions of microplastic pieces per cubic meter from melted Arctic ice cores. The research team identified 17 types of plastic, including some used in packaging materials and others used in paints or fibers. Another 2020 report found lower concentrations for sea ice cores, ranging from 2,000 to 17,000 plastic particles per cubic meter. The 2020 study also found that water beneath ice floes held between 0 to 18 microplastic particles per cubic meter.
In our guts
A 2019 study estimates that an average American consumes between 39,000 and 52,000 pieces of microplastic a year. Researchers came up with this number by drawing on previous studies that had surveyed plastic pieces in tap and bottled water and in certain food items, such as fish, sugar, salt and alcohol. More - in Heart
50 years ago, scientists suspected microbes flourished in clouds
Clouds may be ecosystems — Science News, November 14, 1970
Clouds in the sky may contain living microbial ecosystems…. [Research] determined that metabolic activity, in the form of CO2 uptake into organic material, occurred in [airborne] dust over a 24-hour period, whereas it did not occur in sterilized control dust.
Update
The atmosphere is rich in microbial life. One census documented some 28,000 bacterial species in samples of water from clouds above a mountain in France, scientists reported in 2017. Research building over the last decade or so has supported the claim that some bacteria may indeed be metabolically active within their hazy abodes. One species of Bacillus, for example, eats sugar floating in the atmosphere to build a coating — perhaps to shield itself from ultraviolet radiation and low temperatures (SN: 2/7/15, p. 5). Some scientists suspect cloud bacteria contribute to Earth’s carbon and nitrogen cycles, and even influence weather (SN: 6/18/11, p. 12). The microbes can spur ice crystals to form, triggering rain and snow — and a ride back to Earth’s surface. More - in Heart
Once hurricanes make landfall, they’re lingering longer and staying stronger
Atlantic hurricanes are taking longer to weaken after making landfall than they did 50 years ago, thanks to climate change. Over the past 50 years, increasingly warm ocean waters have juiced up the storms, giving them more staying power after they roar ashore, scientists report in the Nov. 12 Nature. That could potentially extend storms’ destructive power farther inland, the researchers say.
As ocean waters warm, tropical cyclones — called hurricanes in the Atlantic Ocean — are likely to gain in intensity, studies show (SN: 9/28/18). They can also hold more moisture, leading to seemingly unremitting rainfall (SN: 9/13/18). And they may move more slowly, allowing more time to dump that rain on coastal communities. All of this increases the potential hazard on land (SN: 6/6/18).
Once a storm hits land, its energy begins to dissipate. But that relief is coming later than it once did, report physicists Lin Li and Pinaki Chakraborty, both of the Okinawa Institute of Science and Technology in Japan.
Li and Chakraborty analyzed the intensity of historical Atlantic hurricanes over the first 24 hours after landfall. In 1967, a typical storm’s intensity decayed by 76 percent within the first day after landfall. But by 2018, storms were only 52 percent less intense after 24 hours. That trend, the researchers say, aligns with increasing sea-surface temperatures in the Gulf of Mexico and the western Caribbean Sea.
That’s because the intense winds of cyclones feed on moisture and heat picked up from the warm waters, and warmer air can also hold more moisture. So as the oceans heat up, they not only add more moisture, making hurricanes rainier, but also add more heat — like a portable engine the storm uses to fuel its fury for just a bit longer. More
