Now the disturbing new study found that even when plastic ends up in a recycling center, it can still break into smaller pieces that pollute the air and water. This pilot study focused on one new facility where plastic is sorted, crushed and melted into pellets. Along the way, the plastic is washed several times, discarding microplastic particles – fragments less than 5 millimeters in size – into the wastewater of the plant.
Because there were multiple washes, the researchers were able to take water samples at four separate points on the production line. (They do not reveal the name of the facility operator who collaborated with their project.) This plan was actually in the process of installing filters that could trap particles larger than 50 microns (a micron is a millionth of a meter), so the team was able to calculate the concentration of microplastics in wet and filtered wastewater — essentially a before-and-after snapshot of how effective filtration is.
The amount of their microplastics was astronomical. They calculated that even with filtration included, the total discharge of the various washes could produce up to 75 billion particles per cubic meter of wastewater. Depending on the recycling facility, this liquid will eventually end up in city water systems or the environment. In other words, recyclers trying to solve the plastic crisis may actually be making things worse by accident. microplastic crisis that is covered everycornerfromVWednesday with synthetic particles.
“It seems a bit backward that we’re recycling plastic to protect the environment, and then end up exacerbating another and potentially more dangerous problem,” says plastics scientist Erina Brown, who led the research at New York University. Strathclyde.
“This raises very serious concerns,” agrees Judith Enk, president of Beyond Plastics and former regional administrator for the US Environmental Protection Agency, who was not involved in the publication. “And I also think it points to the fact that plastics are fundamentally unstable.”
Grotto Mandrin is not a vast cave; it’s just a deep canopy in the south of France providing protection from the weather. But from the shelter, nestled inside the cliff, there is a panoramic view of the Rhone Valley, once teeming with deer, buffalo and horses. Thus, Neanderthals found the place attractive enough to call home, at least seasonally, for tens of thousands of years. And they were not the only species that settled here. A broken molar and complex stone tips suggest that the first known humans in Europe may have lived here 54,000 years ago, subsequently alternating settlement with Neanderthals over thousands of years of European prehistory.
Now the striking resemblance between these finds and tools from the Middle East, posted Wednesday at PLOS Onemade the Grotte Mandrin the epicenter of an intriguing theory that could write new chapters in the history of how humans populated Europe and what their arrival meant for the Neanderthals who lived on the continent.
A provocative new theory suggests that modern humans colonized Europe in three separate waves of migration from the Middle East, intermittently interacting with Neanderthals over thousands of years as they tried to gain a foothold. French archaeologist Ludovic Slimac believes that the complex stone tools found in France were made using systematic technical methods very similar to those homo sapiens in Lebanon that they must have come from the same culture.
A comparison of thousands of tools and one amazing human tooth led Slimak to theorize that human migration from the Middle East began about 10,000 years earlier than previously thought. And because gun technology went through three very similar stages in each region, Slimak believes it spread from the Middle East to Europe in three different waves of migration. He suggests that it was not until after the third wave, around 45,000–42,000 years ago, that Neanderthals began to die out.
“All this time H. sapiens were there, and we just didn’t see it, because human remains are absolutely rare,” says Slimak from the French National Center for Scientific Research. “Therefore, we were unable to really paint the real story of what happened during the migrations and interactions between homo sapiens and Neanderthals.”
Slimak’s research will no doubt spark controversy and lay the foundation for further research that has much to say about how humans came to power in Europe, what our ancestors’ relationship with Neanderthals was like, and why these Neanderthals, the original inhabitants of Europe, eventually disappeared.
“What I’m suggesting here is predictive, not a definitive demonstration,” he says, noting that future research will determine whether these predictions are correct.
Since excavations began in 1990, the dated archaeological layers of the Grotte Mandrin have created intriguing records of Neanderthal occupation of the site for over 80,000 years. Numerous tools and nine teeth from at least seven people were found in the rock shelter. While most of the teeth appear to be Neanderthal, one 54,000-year-old molar is clearly human. This is surprising because, before this tooth was described in 2022, the earliest widely accepted evidence of modern humans in Europe were tooth and bone fragments from a Bulgarian cave called Bacho Kiro, which contained human DNA dating back to about 45,000 years ago.
Not everyone is entirely convinced that the Grotte Mandrin tooth is definitely human, and not perhaps an unusually shaped young Neanderthal tooth. “It would be so cool if it were true… but it’s not a joke,” said Shara Bailey, a paleoanthropologist at New York University. The science in 2022. And, at least for now, scientists have not been able to recover DNA that could confirm the origin of a molar.
But the tooth is also from a short time layer, about 54,000 years ago, which contains complex stone tools called Neronian, very different from the typical Neanderthal tools found in the surrounding layers, both older and younger. Slimak believes that the nature of the tools and their systematic production represent a completely separate line of evidence from the tooth, which also points to their human origin.
The small, complex flint points are unlike anything else known in Europe at that time. They show standardized technical development, unlike Neanderthal tools, which tend to be more unique than uniform. In a 2023 study, Slimak and others even used local flint to create replicas of various arrowheads and tested their effectiveness using them on dead goats. They found that the smaller ones only proved useful when delivered at the speed of a bow and arrow, although the next evidence of European archery does not appear until 40,000 years later.
Since there was no evidence of human presence in France at the time, some have suggested that the Neanderthal population of the region may have included a unique group that adapted to the production of these complex tools. But at the Peabody Museum at Harvard University, Slimack stumbled upon a treasure trove of ancient artefacts from Ksar Akil, Lebanon — a key Paleolithic site a few miles from Beirut — leading him to a very different conclusion.
“You can read flint like a book,” he says. “This is not just a final product, you can see the technical stages of production. When I opened these boxes, I was very surprised: it was the same technical process. All production steps were the same as in the Grotto Mandrin.”
There are countless ways to emphasize flint, and Slimak emphasizes that it is extremely unlikely that two unrelated groups will use the same system of steps and techniques. “It’s almost impossible, unless you are the same people,” he says. “It was very clear to me that I was facing the same people and the same culture.”
“I think the data for this first phase, its links between the neron at Grotto Mandrin and the lower Upper Paleolithic sequence at Ksar Akil, work very well,” says Gilbert Tostevin, a University of Minnesota archaeologist who was not involved in the study. study.
If sets of tools from areas about 1800 miles apart are indeed indicative of the first human migrations to Europe, Slimak further suggests that the later evolution of toolmaking in these same disparate regions is in fact also indicative of a second wave of migration. According to Slimak, thousands of younger flints known as “sharp blades” at Xar-Aquil show the same uncanny resemblance to another tool tradition from Burgundy to Spain known as Châtelperron. The Chatelperron industry is often (though not unanimously) considered to be Neanderthal, the level of technological progress showing that Neanderthals were influenced by humans who were then beginning to appear in Europe. But Slimak suggests that this is so closely related to human technology from the Middle East that it is probably also the work of people – those who migrated to Europe during the second wave. This assertion is likely to run into problems.
If evolving tool technologies mirroring each other across Europe and the Middle East are indeed indicative of a second wave of human migration, this idea may have implications for our theories about how Neanderthals adapted to the arrival of humans. “The way we understand the last Neanderthals is that they adapted to a completely different lifestyle before their extinction,” says Slimak. But if they didn’t adapt and embrace change with transitional industries such as Châtelperron, could that point to new reasons why they didn’t survive alongside humans?
Our human ancestors and their Neanderthal relatives not only shared space and time during evolutionary history; they also interbred in different places and at different times. Today, most people living outside of sub-Saharan Africa carry Neanderthal genes, between 1 and 4 percent. But scientists aren’t sure how often these groups actually came into contact, or how much they learned from each other at places like Mandarin Grotto, where archeology suggests they likely met.
Tostevin suggests that while such human-Neanderthal hybridization may or may not have occurred at the Grotte Mandarin, it is a key part of the dynamics of Paleolithic Europe that is not recognized in the new theory. “After this first phase of modern humans, most of the Upper Paleolithic was also created by hybrids, humans and Neanderthals,” he notes. Tostevin points out that many key European sites of the era have provided such evidence, from ancient DNA at Bacho Kiro in Bulgaria and the Cave of Bones in Romania to hybrid teeth left in the Channel Islands off the coast of France. “All these sites show people who are only a few generations removed from the admixture between humans and Neanderthals.”
Other scientists say the new theory opens up many opportunities for future research in a number of areas.
“This model is nothing short of a provocation,” says Christian Tryon, an anthropologist at the University of Connecticut and the Smithsonian Descent of Man who did not author the new report but received Slimak credit for helping with the research. “Archaeologists love to connect dots on a map. There is a lot of empty space between the points on these maps,” says Tryon. “What lines of evidence can we find to really connect these dots?”
Tryon notes that finding more places between Lebanon and France might not be easy, partly because the world has changed in the last 50,000 years. “One of the implications of connecting these dots in Lebanon and France is that there must have been people living along the Mediterranean coast, sea travel that we don’t count,” he says. “The problem is that since the sea level rose about 20,000 years ago, these key coastal sites could be under water.”
Other information can be gleaned from ancient DNA, a technology that is rapidly advancing. Marie Soressy, an archaeologist at the University of Leiden in the Netherlands, hopes DNA will help test what she calls an interesting, stimulating and much-anticipated hypothesis. This week Soressi and colleagues published a new method successfully extract human DNA from 20,000-year-old bone and tooth artifacts, revealing who made and processed them in the ancient past. “Applying this new technique to the time period discussed by Slimak will be of great help in testing and developing the theory he put forward,” she says.
A plague of locusts that darken the sky and destroy everything that grows has been known since biblical times and today threatens the food security of millions of people in Asia and Africa.
But a new discovery reported Thursday — a pheromone emitted by insects to avoid cannibalism in a flock — could potentially pave the way for curbing voracious pests.
Study leader Bill Hansson, director of evolutionary neuroethology at the Max Planck Institute, told AFP that the new paper, published in The sciencebased on previous studies that found that swarms are not driven by cooperation, but by the actual threat of consumption by other locusts.
Although disgusted by modern humans, cannibalism is widespread in nature, from lions that kill and devour other cubs to foxes that consume dead relatives for energy.
For locusts, cannibalism is thought to serve an important ecological purpose.
The migratory locust (Locusta migratoria) occurs in many forms and behaves so differently that until recently it was thought that they were completely different species.
Most of the time they exist in a “solitary” phase, keeping to themselves and eating relatively little, like timid grasshoppers.
But when their population density increases due to rains and temporary good breeding conditions followed by food shortages, they undergo major behavioral changes due to the release of hormones that activate them, causing them to flock and become more aggressive.
According to a 2020 study by Ian Cousin of the Max Planck Institute, this is known as the “herd” phase, and the fear of cannibalism is thought to help the swarm move in one direction, from an area of lower to higher food concentration. for animal research.
Hansson explained that “the locusts eat each other from behind”.
“So if you stop moving, you will be eaten by another, and this led us to believe that almost every endangered animal has some kind of countermeasure.”
Through painstaking experiments that took four years to complete, Hansson’s team established for the first time that rates of cannibalism did increase as the number of “herd” caged locusts increased, proving in the lab what Cousin observed in the field in Africa (t .trigger point was around 50 per cage).
They then compared the scents emitted by solitary and gregarious locusts and found 17 odors emitted exclusively during the gregarious phase.
One of these, known as phenylacetonitrile (PAN), has been found to repel other locusts in behavioral tests.
PAN is involved in the synthesis of a potent toxin sometimes produced by locust locusts—hydrogen cyanide—so the release of PAN seems to be appropriate as a signal to tell others to back off.
To confirm the discovery, they used CRISPR editing to genetically modify the locust so that it could no longer produce PAN, which in turn made it more vulnerable to cannibalism.
To further confirm, they tested dozens of locust olfactory receptors and eventually settled on one that was highly sensitive to PAN.
When they edited the locust’s gene so that it no longer produces this receptor, the modified locust became more cannibalistic.
Researchers Ian Cousin and Einat Cousin-Fuchs wrote in a related commentary in the journal Science that the discovery helped shed light on the “complex balance” between mechanisms that cause migratory locusts to cluster together rather than compete with each other.
So future locust control methods may use technologies that tip this delicate balance in the direction of increased competition, but Hansson warned: “You don’t want to eradicate this species.”
“If we could reduce the size of the swarms, send them to areas where we do not grow our crops, then a lot could be gained,” he added.
quotes: Scientists Find Chemical That Stops Locust Cannibalism (2023 May 7), retrieved May 7, 2023 from https://phys.org/news/2023-05-scientists-chemical-locust-cannibalism.html.
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