Ancient hunters stayed in frozen Northern Europe rather than migrating to warmer areas, evidence from Arctic fox bones shows

 Ancient hunters stayed in the coldest part of Northern Europe rather than migrating to escape freezing winter conditions, archaeologists have found.

Evidence from Arctic fox bones show communities living around 27,500 years ago were killing small prey in the inhospitable North European Plains during the winter months of the last Ice Age.

Researchers have found no evidence of dwellings, suggesting people only stayed for a short time or lived in tents in the area excavated, Kraków Spadzista in Southern Poland -- one of the largest Upper Palaeolithic sites in Central Europe. Until now it wasn't clear if people retreated elsewhere each winter to avoid the intense cold.

Dr Alexander Pryor, from the University of Exeter, who led the study, said: "Our research shows the cold harsh winter climates of the last ice age were no barrier to human activity in the area. Hunters made very specific choices about where and when to kill their prey."

Inhabitants of Kraków Spadzista around 27,500 years ago killed and butchered large numbers of woolly mammoths and arctic foxes at the site. For the first time, the research team were able to reconstruct details of how the foxes were moving around in the landscape before they died, and also what time of the year they died, through analysing the internal chemistry and growth structures of their tooth enamel and roots.

The analysis of teeth from four of the 29 hunted foxes show each was born and grew up in a different location, and had migrated either tens or hundreds of kilometres to the region before being killed by hunters -- by snares, deadfalls or other trapping methods -- for both their thick warm furs as well as meat and fat for food. The carcasses were brought back to the site to be skinned and butchered.

Analysis of the dental cementum of at least 10 fox individuals demonstrate that the majority were killed between late winter and late spring, most likely in late winter. The foxes ranged in age, from sub-adult to very old.

The study, published in the Journal of Archaeological Science: Reports, also involved Sylwia Pospuła, Piotr Wojtal, Nina Kowalik and Jarosław Wilczyński from the Polish Academy of Sciences and Tereza Nesnídalová from the University of Exeter.

Around 2,400 arctic fox bones were found about 30m south of a huge concentration of bones from more than 100 individual woolly mammoths that dominate the site, in an area used for the production of lithic tools and the processing of smaller prey animals.

The study suggests the Arctic fox colonised the area because they moved over long distances season by season, something they still do today, in order to find food.

Dr Pryor said: "Arctic fox provided both food and hides to Palaeolithic hunters, with their fur coats reaching full length around the beginning of December; this winter fur usually begins shedding by early spring. They also lay down substantial stores of body fats seasonally that are greatest from late autumn throughout the winter season and do not start to become seriously depleted until early spring. Hunters most likely targeted the foxes in the late winter period -- before the onset of fur shedding and loss of critical fat supplies.

"The high numbers of fox remains found at the site suggests what was happening was a deliberate, organised procurement strategy rather than just simple incidental hunting."

The analysis of teeth suggests hunters engaged in large-scale winter hunting of solitary Arctic foxes that were ranging widely across the landscape. The site was used as a base camp for ranging visits to maintain trapping lines and for processing hides.

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Lost frogs rediscovered with environmental DNA

 Scientists have detected signs of a frog listed extinct and not seen since 1968, using an innovative technique to locate declining and missing species in two regions of Brazil.

The frog, Megaelosia bocainensis, was among seven total species -- including four other declining species, and two that had disappeared locally for many years -- that were detected. The findings appeared in a paper, "Lost and Found: Frogs in a Biodiversity Hotspot Rediscovered with Environmental DNA," published in August in Molecular Ecology.

Megaelosia bocainensis. A disappeared species from Parque Nacional da Serra da Bocaina, Brazil, known only from this museum specimen collected in 1968, and detected by eDNA surveys. In the study, the researchers collected and screened environmental DNA (eDNA) in the biodiverse Atlantic Coastal Forest and Cerrado grasslands of Brazil.

The eDNA technique offers a way to survey that can confirm the presence of species undetected by traditional methods, providing a tool for conservation scientists to evaluate the presence of threatened species, especially those with low population densities and those not seen in years.

After careful research to identify species at various levels of threat in these regions of Brazil, the researchers used the eDNA method to search for 30 target amphibian species in six localities where the frogs were known to previously live.

"Little bits of DNA in the environment don't tell us about how many individuals there are or whether those individuals are healthy, but it does tell us that the species is still present," said senior author Kelly Zamudio, the Goldwin Smith Professor of Ecology and Evolutionary Biology in the College of Arts and Sciences.

"This is one more kind of survey data, and for species that are declining or locally disappeared, it not only means they are there, but there's now the potential to study them in more detail," she said, noting that for many species, very little is known.

Around the world, conservationists have been challenged to keep pace with declining and disappearing amphibians. At the same time, living organisms leave DNA traces in the soil, water and air. Now, scientists are increasingly using highly sensitive sampling techniques to detect eDNA for conservation purposes.

In the study, the researchers targeted 13 frog species that have totally disappeared and are presumed extinct; 12 frogs that have disappeared locally but are still found in other parts of their range; and five species that were once very abundant and are still there but hard to find.

The researchers hiked into the sampling sites carrying battery packs, a shoebox-sized peristaltic pump and backpacks of sterile tubing. They used the pump and tubing to draw up to 60 liters of stream or pond water through a capsule fitted with a filter for capturing DNA. A buffer was then applied to stabilize and preserve the DNA on the filter.

Back in the lab, the researchers extracted the DNA, genetically sequenced it, weeded out genetic material from humans, pigs, chickens and other organisms until they could isolate all the frog DNA.

"Now you've got a subset of genetic sequences that we know only belong to frogs, and then it's step by step, going finer and finer, until you get to the genus and species you are looking for," Zamudio said.

Identifying M. bocainensis required clever detective work: The species disappeared long ago, and there were no tissues from which to extract DNA for comparison with the eDNA. But the researchers did have the sequences for all the sister species in the genus Megaelosia and they knew the ranges of the sister species and M. bocainensis.

"We know there's a Megaelosia there," Zamudio said, "we just don't know which one it is, but the only one that has ever been reported there historically is the one that went missing. Do we believe it? That's how far the analysis can take us."

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How to have a blast like a black hole

 Laser Engineering at Osaka University have successfully used short, but extremely powerful laser blasts to generate magnetic field reconnection inside a plasma. This work may lead to a more complete theory of X-ray emission from astronomical objects like black holes.

In addition to being subjected to extreme gravitational forces, matter being devoured by a black hole can be also be pummeled by intense heat and magnetic fields. Plasmas, a fourth state of matter hotter than solids, liquids, or gasses, are made of electrically charged protons and electrons that have too much energy to form neutral atoms. Instead, they bounce frantically in response to magnetic fields. Within a plasma, magnetic reconnection is a process in which twisted magnetic field lines suddenly "snap" and cancel each other, resulting in the rapid conversion of magnetic energy into particle kinetic energy. In stars, including our sun, reconnection is responsible for much of the coronal activity, such as solar flares. Owing to the strong acceleration, the charged particles in the black hole's accretion disk emit their own light, usually in the X-ray region of the spectrum.

To better understand the process that gives rise to the observed X-rays coming from black holes, scientists at Osaka University used intense laser pulses to create similarly extreme conditions on the lab. "We were able to study the high-energy acceleration of electrons and protons as the result of relativistic magnetic reconnection," Senior author Shinsuke Fujioka says. "For example, the origin of emission from the famous black hole Cygnus X-1, can be better understood."

This level of light intensity is not easily obtained, however. For a brief instant, the laser required two petawatts of power, equivalent to one thousand times the electric consumption of the entire globe. With the LFEX laser, the team was able to achieve peak magnetic fields with a mind-boggling 2,000 telsas. For comparison, the magnetic fields generated by an MRI machine to produce diagnostic images are typically around 3 teslas, and Earth's magnetic field is a paltry 0.00005 teslas. The particles of the plasma become accelerated to such an extreme degree that relativistic effects needed to be considered.

"Previously, relativistic magnetic reconnection could only be studied via numerical simulation on a supercomputer. Now, it is an experimental reality in a laboratory with powerful lasers," first author King Fai Farley Law says. The researchers believe that this project will help elucidate the astrophysical processes that can happen at places in the Universe that contain extreme magnetic fields.

From Science Daily

Children use both brain hemispheres to understand language, unlike adults

 Infants and young children have brains with a superpower, of sorts, say Georgetown University Medical Center neuroscientists. Whereas adults process most discrete neural tasks in specific areas in one or the other of their brain's two hemispheres, youngsters use both the right and left hemispheres to do the same task. The finding suggests a possible reason why children appear to recover from neural injury much easier than adults.

The study published Sept. 7, 2020 in PNAS focuses on one task, language, and finds that to understand language (more specifically, processing spoken sentences), children use both hemispheres. This finding fits with previous and ongoing research, led by Georgetown neurology professor Elissa L. Newport, PhD, a former postdoctoral fellow Olumide Olulade, MD, PhD, and neurology assistant professor Anna Greenwald, PhD.

"This is very good news for young children who experience a neural injury," says Newport, director of the Center for Brain Plasticity and Recovery, a joint enterprise of Georgetown University and MedStar National Rehabilitation Network. "Use of both hemispheres provides a mechanism to compensate after a neural injury. For example, if the left hemisphere is damaged from a perinatal stroke -- one that occurs right after birth -- a child will learn language using the right hemisphere. A child born with cerebral palsy that damages only one hemisphere can develop needed cognitive abilities in the other hemisphere. Our study demonstrates how that is possible."

Their study solves a mystery that has puzzled clinicians and neuroscientists for a long time, says Newport.

In almost all adults, sentence processing is possible only in the left hemisphere, according to both brain scanning research and clinical findings of language loss in patients who suffered a left hemisphere stroke.

But in very young children, damage to either hemisphere is unlikely to result in language deficits; language can be recovered in many patients even if the left hemisphere is severely damaged. These facts suggest that language is distributed to both hemispheres early in life, Newport says. However, traditional scanning had not revealed the details of these phenomena until now. "It was unclear whether strong left dominance for language is present at birth or appears gradually during development," explains Newport.

Now, using functional magnetic resonance imaging (fMRI) analyzed in a more complex way, the researchers have shown that the adult lateralization pattern is not established in young children and that both hemispheres participate in language during early development.

Brain networks that localize specific tasks to one or the other hemisphere start during childhood but are not complete until a child is about 10 or 11, she says. "We now have a better platform upon which to understand brain injury and recovery."

The study, originally run by collaborators William D. Gaillard, MD, and Madison M. Berl, PhD, of Children's National Medical Center, enrolled 39 healthy children, ages 4-13; Newport's lab added 14 adults, ages 18-29, and conducted a series of new analyses of both groups. The participants were given a well-studied sentence comprehension task. The analyses examined fMRI activation patterns in each hemisphere of the individual participants, rather than looking at overall lateralization in group averages. Investigators then compared the language activation maps for four age groups: 4-6, 7-9, 10-13, and 18-29. Penetrance maps revealed the percentage of subjects in each age group with significant language activation in each voxel of each hemisphere. (A voxel is a tiny point in the brain image, like a pixel on a television monitor.) Investigators also performed a whole-brain analysis across all participants to identify brain areas in which language activation was correlated with age.

Researchers found that, at the group level, even young children show left-lateralized language activation. However, a large proportion of the youngest children also show significant activation in the corresponding right-hemisphere areas. (In adults, the corresponding area in the right hemisphere is activated in quite different tasks, for example, processing emotions expressed with the voice. In young children, areas in both hemispheres are each engaged in comprehending the meaning of sentences as well as recognizing the emotional affect.)

Newport believes that the "higher levels of right hemisphere activation in a sentence processing task and the slow decline in this activation over development are reflections of changes in the neural distribution of language functions and not merely developmental changes in sentence comprehension strategies."

She also says that, if the team were able to do the same analysis in even younger children, "it is likely we would see even greater functional involvement of the right hemisphere in language processing than we see in our youngest participants (ages 4-6 years old).

"Our findings suggest that the normal involvement of the right hemisphere in language processing during very early childhood may permit the maintenance and enhancement of right hemisphere development if the left hemisphere is injured," Newport says.

Read more at Science Daily

Researchers track nutrient transport in the Gulf of Mexico

 Researchers from Florida State University are shedding light on nutrient levels in the Gulf of Mexico with new findings published this month in the Journal of Geophysical Research -- Oceans.

The Gulf of Mexico receives considerable levels of nutrients from the rivers that empty into it, especially the Mississippi River, which causes the Gulf's northern shelf waters to become overly enriched and more susceptible to algae growth. But scientists have remained unsure whether a significant portion of those nutrients ever leave the Gulf to potentially impact the chemistry of the North Atlantic Ocean.

"The Gulf of Mexico is an economically important body of water, as the surrounding areas rely on it for tourism, fisheries and oil production, and it also has significant ecological diversity," said Samantha Howe, a graduate student in the College of Arts and Sciences' Department of Earth, Ocean and Atmospheric Science, who led the research. "It is important to track the nutrient input from the Mississippi and Atchafalaya River System to the Gulf as those nutrients contribute to harmful algal blooms on the Northern Gulf Shelf."

Researchers found no evidence that nitrate from the Mississippi-Atchafalaya River System is mixing across the Northern Gulf shelf into the open waters of the Gulf of Mexico. The findings are consistent with recent modeling work by fellow scientists that indicates 90 percent of Mississippi River nutrients are retained in the near-shore ecosystem, which implies that nutrients from the Mississippi River do not leave the Gulf.

"In order to assess and manage ecological challenges in the Gulf, it is critical to understand whether the nutrients are processed and retained nearshore or whether they are transported to the North Atlantic," Howe said. "This finding is valuable to know, as these ecosystems must harbor the nutrient burden."

To conduct the study, the team collected and analyzed water samples taken during four different research cruises to the Gulf and the Florida Straits from 2011 to 2018.

The research is the first ever to provide isotopic composition measurements of nitrate in the Gulf of Mexico, as well as a new isotopic profile from the Florida Straits. These new water column profiles were then compared with prior measurements from the North and South Atlantic and with the magnitude of nitrogen inputs to the Gulf.

Howe, who earned her bachelor's degree in environmental science from FSU in Spring 2019, is now pursuing her master's in aquatic environmental science. She began the nutrient research as part of her honors undergraduate thesis while working in the research lab of study co-author, Associate Professor of Oceanography Angela Knapp.

"Samantha's thesis looked for distinct geochemical signatures of nitrate from the Mississippi River and whether this nitrate made it off the Northern Gulf of Mexico shelf into the deep waters of the Gulf that mix with the Loop Current and leave via the Florida Straits to enter the North Atlantic," Knapp said.

Howe's collaborators on the study include co-authors Knapp and Carlos Miranda, a 2017 graduate of the FSU Department of Chemistry and Biochemistry and the FSU Department of Biological Science, and colleagues from the University of Southern Mississippi and the University of New Hampshire.

 Read more at Science Daily

Meteorite study suggests Earth may have been wet since it formed

 

Planet Earth

A new study finds that Earth's water may have come from materials that were present in the inner solar system at the time the planet formed -- instead of far-reaching comets or asteroids delivering such water. The findings published Aug. 28 in Science suggest that Earth may have always been wet.

Researchers from the Centre de Recherches Petrographiques et Geochimiques (CRPG, CNRS/Universite de Lorraine) in Nancy, France, including one who is now a postdoctoral fellow at Washington University in St. Louis, determined that a type of meteorite called an enstatite chondrite contains sufficient hydrogen to deliver at least three times the amount of water contained in the Earth's oceans, and probably much more.

Enstatite chondrites are entirely composed of material from the inner solar system -- essentially the same stuff that made up the Earth originally.

"Our discovery shows that the Earth's building blocks might have significantly contributed to the Earth's water," said lead author Laurette Piani, a researcher at CPRG. "Hydrogen-bearing material was present in the inner solar system at the time of the rocky planet formation, even though the temperatures were too high for water to condense."

The findings from this study are surprising because the Earth's building blocks are often presumed to be dry. They come from inner zones of the solar system where temperatures would have been too high for water to condense and come together with other solids during planet formation.

The meteorites provide a clue that water didn't have to come from far away.

"The most interesting part of the discovery for me is that enstatite chondrites, which were believed to be almost 'dry,' contain an unexpectedly high abundance of water," said Lionel Vacher, a postdoctoral researcher in physics in Arts & Sciences at Washington University in St. Louis.

Vacher prepared some of the enstatite chondrites in this study for water analysis while he was completing his PhD at Universite de Lorraine. At Washington University, Vacher is working on understanding the composition of water in other types of meteorites.

Enstatite chondrites are rare, making up only about 2 percent of known meteorites in collections.

But their isotopic similarity to Earth make them particularly compelling. Enstatite chondrites have similar oxygen, titanium and calcium isotopes as Earth, and this study showed that their hydrogen and nitrogen isotopes are similar to Earth's, too. In the study of extraterrestrial materials, the abundances of an element's isotopes are used as a distinctive signature to identify where that element originated.

"If enstatite chondrites were effectively the building blocks of our planet -- as strongly suggested by their similar isotopic compositions -- this result implies that these types of chondrites supplied enough water to Earth to explain the origin of Earth's water, which is amazing!" Vacher said.

The paper also proposes that a large amount of the atmospheric nitrogen -- the most abundant component of the Earth's atmosphere -- could have come from the enstatite chondrites.

"Only a few pristine enstatite chondrites exist: ones that were not altered on their asteroid nor on Earth," Piani said. "In our study we have carefully selected the enstatite chondrite meteorites and applied a special analytical procedure to avoid being biased by the input of terrestrial water."

Coupling two analytical techniques -- conventional mass spectrometry and secondary ion mass spectrometry (SIMS) -- allowed researchers to precisely measure the content and composition of the small amounts of water in the meteorites.

Read more at Science Daily

Ancient bony fish forces rethink of how sharks evolved

 Sharks' non-bony skeletons were thought to be the template before bony internal skeletons evolved, but a new fossil discovery suggests otherwise.

The discovery of a 410-million-year-old fish fossil with a bony skull suggests the lighter skeletons of sharks may have evolved from bony ancestors, rather than the other way around.

Sharks have skeletons made cartilage, which is around half the density of bone. Cartilaginous skeletons are known to evolve before bony ones, but it was thought that sharks split from other animals on the evolutionary tree before this happened; keeping their cartilaginous skeletons while other fish, and eventually us, went on to evolve bone.

Now, an international team led by Imperial College London, the Natural History Museum and researchers in Mongolia have discovered a fish fossil with a bony skull that is an ancient cousin of both sharks and animals with bony skeletons. This could suggest the ancestors of sharks first evolved bone and then lost it again, rather than keeping their initial cartilaginous state for more than 400 million years.

The team published their findings today in Nature Ecology & Evolution.

Lead researcher Dr Martin Brazeau, from the Department of Life Sciences at Imperial, said: "It was a very unexpected discovery. Conventional wisdom says that a bony inner skeleton was a unique innovation of the lineage that split from the ancestor of sharks more than 400 million years ago, but here is clear evidence of bony inner skeleton in a cousin of both sharks and, ultimately, us."

Most of the early fossils of fish have been uncovered in Europe, Australia and the USA, but in recent years new finds have been made in China and South America. The team decided to dig in Mongolia, where there are rocks of the right age that have not been searched before.

They uncovered the partial skull, including the brain case, of a 410-million-year-old fish. It is a new species, which they named Minjinia turgenensis, and belongs to a broad group of fish called 'placoderms', out of which sharks and all other 'jawed vertebrates' -- animals with backbones and mobile jaws -- evolved.

When we are developing as foetuses, humans and bony vertebrates have skeletons made of cartilage, like sharks, but a key stage in our development is when this is replaced by 'endochondral' bone -- the hard bone that makes up our skeleton after birth.

Previously, no placoderm had been found with endochondral bone, but the skull fragments of M. turgenensis were "wall-to-wall endochondral." While the team are cautious not to over-interpret from a single sample, they do have plenty of other material collected from Mongolia to sort through and perhaps find similar early bony fish.

And if further evidence supports an early evolution of endochondral bone, it could point to a more interesting history for the evolution of sharks.

Dr Brazeau said: "If sharks had bony skeletons and lost it, it could be an evolutionary adaptation. Sharks don't have swim bladders, which evolved later in bony fish, but a lighter skeleton would have helped them be more mobile in the water and swim at different depths.

Read more at Science Daily

'Wild West' mentality lingers in modern populations of US mountain regions

 When historian Frederick Jackson Turner presented his famous thesis on the US frontier in 1893, he described the "coarseness and strength combined with acuteness and acquisitiveness" it had forged in the American character.

Now, well into the 21st century, researchers led by the University of Cambridge have detected remnants of the pioneer personality in US populations of once inhospitable mountainous territory, particularly in the Midwest.

A team of scientists algorithmically investigated how landscape shapes psychology. They analysed links between the anonymised results of an online personality test completed by over 3.3 million Americans, and the "topography" of 37,227 US postal -- or ZIP -- codes.

The researchers found that living at both a higher altitude and an elevation relative to the surrounding region -- indicating "hilliness" -- is associated with a distinct blend of personality traits that fits with "frontier settlement theory."

"The harsh and remote environment of mountainous frontier regions historically attracted nonconformist settlers strongly motivated by a sense of freedom," said researcher Friedrich Götz, from Cambridge's Department of Psychology.

"Such rugged terrain likely favoured those who closely guarded their resources and distrusted strangers, as well as those who engaged in risky explorations to secure food and territory."

"These traits may have distilled over time into an individualism characterised by toughness and self-reliance that lies at the heart of the American frontier ethos" said Götz, lead author of the study.

"When we look at personality across the whole United States, we find that mountainous residents are more likely to have psychological characteristics indicative of this frontier mentality."

Götz worked with colleagues from the Karl Landsteiner University of Health Sciences, Austria, the University of Texas, US, the University of Melbourne in Australia, and his Cambridge supervisor Dr Jason Rentfrow. The findings are published in the journal Nature Human Behaviour.

The research uses the "Big Five" personality model, standard in social psychology, with simple online tests providing high-to-low scores for five fundamental personality traits of millions of Americans.

The mix of characteristics uncovered by study's authors consists of low levels of "agreeableness," suggesting mountainous residents are less trusting and forgiving -- traits that benefit "territorial, self-focused survival strategies."

Low levels of "extraversion" reflect the introverted self-reliance required to thrive in secluded areas, and a low level of "conscientiousness" lends itself to rebelliousness and indifference to rules, say researchers.

"Neuroticism" is also lower, suggesting an emotional stability and assertiveness suited to frontier living. However, "openness to experience" is much higher, and the most pronounced personality trait in mountain dwellers.

"Openness is a strong predictor of residential mobility," said Götz. "A willingness to move your life in pursuit of goals such as economic affluence and personal freedom drove many original North American frontier settlers."

"Taken together, this psychological fingerprint for mountainous areas may be an echo of the personality types that sought new lives in unknown territories."

The researchers wanted to distinguish between the direct effects of physical environment and the "sociocultural influence" of growing up where frontier values and identities still hold sway.

To do this, they looked at whether mountainous personality patterns applied to people born and raised in these regions that had since moved away.

The findings suggest some "initial enculturation" say researchers, as those who left their early mountain home are still consistently less agreeable, conscientious and extravert, although no such effects were observed for neuroticism and openness.

The scientists also divided the country at the edge of St. Louis -- "gateway to the West" -- to see if there is a personality difference between those in mountains that made up the historic frontier, such as the Rockies, and eastern ranges e.g. the Appalachians.

While mountains continue to be a "meaningful predictor" of personality type on both sides of this divide, key differences emerged. Those in the east are more agreeable and outgoing, while western ranges are a closer fit for frontier settlement theory.

In fact, the mountainous effect on high levels of "openness to experience" is ten times as strong in residents of the old western frontier as in those of the eastern ranges.

The findings suggest that, while ecological effects are important, it is the lingering sociocultural effects -- the stories, attitudes and education -- in the former "Wild West" that are most powerful in shaping mountainous personality, according to scientists.

They describe the effect of mountain areas on personality as "small but robust," but argue that complex psychological phenomena are influenced by many hundreds of factors, so small effects are to be expected.

Read more at Science Daily

Bering Sea ice extent is at most reduced state in last 5,500 years

 Through the analysis of vegetation from a Bering Sea island, researchers have determined that the extent of sea ice in the region is lower than it's been for thousands of years.

A newly published paper in the journal Science Advances describes how a peat core from St. Matthew Island is providing a look back in time. By analyzing the chemical composition of the core, which includes plant remains from 5,500 years ago to the present, scientists can estimate how sea ice in the region has changed during that time period.

"It's a small island in the middle of the Bering Sea, and it's essentially been recording what's happening in the ocean and atmosphere around it," said lead author Miriam Jones, a research geologist with the U.S. Geological Survey. Jones worked as a faculty researcher at the University of Alaska Fairbanks when the project began in 2012.

The ancient sea ice record comes in the form of changes in the relative amounts of two isotopes of the element oxygen -- oxygen-16 and oxygen-18. The ratio of those two isotopes changes depending on patterns in the atmosphere and ocean, reflecting the different signatures that precipitation has around the globe. More oxygen-18 makes for an isotopically "heavier" precipitation, more oxygen-16 makes precipitation "lighter."

By analyzing data from a model that tracks atmospheric movement using the isotopic signature of precipitation, the authors found that heavier precipitation originated from the North Pacific, while lighter precipitation originated from the Arctic.

A "heavy" ratio signals a seasonal pattern that causes the amount of sea ice to decrease. A "light" ratio indicates a season with more sea ice. That connection has been confirmed though sea ice satellite data collected since 1979, and to a smaller extent, through the presence of some microorganisms in previous core samples.

UAF's Alaska Stable Isotope Facility analyzed isotope ratios throughout the peat layers, providing a time stamp for ice conditions that existed through the millennia.

After reviewing the isotopic history, researchers determined that modern ice conditions are at remarkably low levels.

"What we've seen most recently is unprecedented in the last 5,500 years," said Matthew Wooller, director of the Alaska Stable Isotope Facility and a contributor to the paper. "We haven't seen anything like this in terms of sea ice in the Bering Sea."

Jones said the long-term findings also affirm that reductions in Bering Sea ice are due to more than recent higher temperatures associated with global warming. Atmospheric and ocean currents, which are also affected by climate change, play a larger role in the presence of sea ice.

Read more at Science Daily

A 400-year-old chamois will serve as a model for research on ice mummies

 At first glance, the chamois carcass did not seem to Hermann Oberlechner to be an unusual discovery as mountaineers often happen across the remains of wild animals during their high-altitude excursions. However, upon a close inspection of the chamois skin, the Ahrntal alpinist realised that he was faced with a highly unique discovery and informed the relevant ranger.

The chamois had in fact been protected by the glacier for 400 years and only recently released due to the ice having receded. With the help of the Alpine Army Corps, the chamois mummy was brought back to the valley and entrusted to Eurac Research for scientific study by the Department of Cultural Heritage. Due to their age and state of preservation, the remains are in fact a perfect simulant of a human mummy and will allow researchers to improve the conservation techniques of ice mummies all over the world while determining methods for the safeguarding of ancient DNA -- a mine of valuable information for humanity.

In mummified specimens, DNA has often degraded and is present only in minimal amounts. In fact, faced with a new discovery, the first question experts encounter is how to examine the mummy while continuing to preserve it, without damaging its ancient DNA. Every action has irreversible consequences on DNA fragments, which makes experimenting with new techniques on human finds impossible. Contrastingly, an intact animal mummy is a perfect simulant for research -- especially if its conditions are similar to those of the world's other ice mummies, of which Ötzi and the Inca girl Juanita are among the most famous.

"Thanks to our previous studies we know the optimal physical and chemical parameters for preservation from a microbiological point of view. In the laboratory we will bring the chamois to those conditions and focus on their effects on DNA. With repeated in-depth analysis we will verify what alterations the DNA undergoes when external conditions change," explains Marco Samadelli, conservation expert at Eurac Research. "Our goal is to use scientific data to develop a globally valid conservation protocol for ice mummies. This is the first time an animal mummy has been used in this way," adds Albert Zink, Director of the Institute for Mummy Studies at Eurac Research.

Upon encountering the chamois, Hermann Oberlechner soon realised the importance of the find. "Only half of the animal's body was exposed from the snow. The skin looked like leather, completely hairless; I had never seen anything like it. I immediately took a photo and sent it to the park ranger, together we then notified the Department of Cultural Heritage."

The discovery site, at 3200 m MSL, is impassable and can only be reached by a six-hour hike. For this reason, following their initial inspection, the researchers decided to ask for the support of the Alpine Army Corps in the recovery of the animal. "The request from Eurac Research came during a training phase of our military mountain rescue team. We plan regular exercises not only in order to always be ready to intervene and protect our personnel in high-altitude missions, but also if we are requested for civil protection too." commented Mario Bisica, Alpine Army Corps Head of Public Information and Communication.

The helicopter flight was organised in collaboration with the army's specialised aviation corps, who have their own regiment in Bolzano, with pilots specifically trained to operate at high altitude. Thanks to the group effort, Eurac Research experts were able to reach the glacier and, with the help of the troops, carry out the scientific operation needed to recover the mummy. The chamois was then wrapped in an inert material casing made to measure by conservationist Marco Samadelli. The remains are now being kept at the Eurac Research Conservation Laboratory at NOI Techpark in refrigerated cell at -- 5 C°, ready to be studied.

Read more at Science Daily