Traces of Earth's early magma ocean identified in Greenland rocks

UNIVERSITY OF CAMBRIDGE

Research News

 

IMAGE: AT FIRST GLANCE THE ROCKS THAT MAKE UP GREENLAND'S ISUA SUPRACRUSTAL BELT LOOK JUST LIKE ANY MODERN BASALT YOU'D FIND ON THE SEA FLOOR. BUT THIS OUTCROP, WHICH WAS FIRST... view more 

CREDIT: HANIKA RIZO

New research led by the University of Cambridge has found rare evidence - preserved in the chemistry of ancient rocks from Greenland - which tells of a time when Earth was almost entirely molten.

The study, published in the journal Science Advances, yields information on a important period in our planet's formation, when a deep sea of incandescent magma stretched across Earth's surface and extended hundreds of kilometres into its interior.

It is the gradual cooling and crystallisation of this 'magma ocean' that set the chemistry of Earth's interior - a defining stage in the assembly of our planet's structure and the formation of our early atmosphere.

Scientists know that catastrophic impacts during the formation of the Earth and Moon would have generated enough energy to melt our planet's interior. But we don't know much about this distant and fiery phase of Earth's history because tectonic processes have recycled almost all rocks older than 4 billion years.

Now researchers have found the chemical remnants of the magma ocean in 3.6-billion-year-old rocks from southwestern Greenland.

The findings support the long-held theory that Earth was once almost entirely molten and provide a window into a time when the planet started to solidify and develop the chemistry that now governs its internal structure. The research suggests that other rocks on Earth's surface may also preserve evidence of ancient magma oceans.

"There are few opportunities to get geological constraints on the events in the first billion years of Earth's history. It's astonishing that we can even hold these rocks in our hands - let alone get so much detail about the early history of our planet," said lead author Dr Helen Williams, from Cambridge's Department of Earth Sciences.

The study brings forensic chemical analysis together with thermodynamic modelling in search of the primeval origins of the Greenland rocks, and how they got to the surface.

At first glance, the rocks that make up Greenland's Isua supracrustal belt look just like any modern basalt you'd find on the sea floor. But this outcrop, which was first described in the 1960s, is the oldest exposure of rocks on Earth. It is known to contain the earliest evidence of microbial life and plate tectonics.

The new research shows that the Isua rocks also preserve rare evidence which even predates plate tectonics - the residues of some of the crystals left behind as that magma ocean cooled.

"It was a combination of some new chemical analyses we did and the previously published data that flagged to us that the Isua rocks might contain traces of ancient material. The hafnium and neodymium isotopes were really tantalizing, because those isotope systems are very hard to modify - so we had to look at their chemistry in more detail," said co-author Dr Hanika Rizo, from Carleton University.

Iron isotopic systematics confirmed to Williams and the team that the Isua rocks were derived from parts of the Earth's interior that formed as a consequence of magma ocean crystallisation.

Most of this primeval rock has been mixed up by convection in the mantle, but scientists think that some isolated zones deep at the mantle-core boundary - ancient crystal graveyards - may have remained undisturbed for billions of years.

It's the relics of these crystal graveyards that Williams and her colleagues observed in the Isua rock chemistry. "Those samples with the iron fingerprint also have a tungsten anomaly - a signature of Earth's formation - which makes us think that their origin can be traced back to these primeval crystals," said Williams.

But how did these signals from the deep mantle find their way up to the surface? Their isotopic makeup shows they were not just funnelled up from melting at the core-mantle boundary. Their journey was more circuitous, involving several stages of crystallization and remelting - a kind of distillation process. The mix of ancient crystals and magma would have first migrated to the upper mantle, where it was churned up to create a 'marble cake' of rocks from different depths. Later melting of that hybrid of rocks is what produced the magma which fed this part of Greenland.

The team's findings suggest that modern hotspot volcanoes, which are thought to have formed relatively recently, may actually be influenced by ancient processes.

"The geochemical signals we report in the Greenland rocks bear similarities to rocks erupted from hotspot volcanoes like Hawaii - something we are interested in is whether they might also be tapping into the depths and accessing regions of the interior usually beyond our reach," said Dr Oliver Shorttle, who is jointly based at Cambridge's Department of Earth Sciences and Institute of Astronomy.

The team's findings came out of a project funded by Deep Volatiles, a NERC-funded 5-year research programme. They now plan to continue their quest to understand the magma ocean by widening their search for clues in ancient rocks and experimentally modelling isotopic fractionation in the lower mantle.

"We've been able to unpick what one part of our planet's interior was doing billions of years ago, but to fill in the picture further we must keep searching for more chemical clues in ancient rocks," said co-author Dr Simon Matthews from the University of Iceland.

Scientists have often been reluctant to look for chemical evidence of these ancient events. "The evidence is often altered by the course of time. But the fact we found what we did suggests that the chemistry of other ancient rocks may yield further insights into the Earth's formation and evolution - and that's immensely exciting," said Williams.

Zealandia Switch may be the missing link in understanding ice age climates

UNIVERSITY OF MAINE

Research News

 

IMAGE: MORAINES CONSTRUCTED DURING REPEATED ADVANCE-RETREAT CYCLES OF ONE OF THE GLACIERS THAT EXTENDED OUT FROM THE SOUTHERN ALPS IN NEW ZEALAND DURING THE LAST ICE AGE. AROUND 18,000 YEARS AGO,... view more 

CREDIT: PHOTO COURTESY OF AARON PUTNAM

Orono, Maine -- The origins of ice age climate changes may lie in the Southern Hemisphere, where interactions among the westerly wind system, the Southern Ocean and the tropical Pacific can trigger rapid, global changes in atmospheric temperature, according to an international research team led by the University of Maine.

The mechanism, dubbed the Zealandia Switch, relates to the general position of the Southern Hemisphere westerly wind belt -- the strongest wind system on Earth -- and the continental platforms of the southwest Pacific Ocean, and their control on ocean currents. Shifts in the latitude of the westerly winds affects the strength of the subtropical oceanic gyres and, in turn, influences the release of energy from the tropical ocean waters, the planet's "heat engine." Tropical heat spreads rapidly through the atmosphere and ocean to the polar regions of both hemispheres, acting as the planet's thermostat.

The Southern Hemisphere climate dynamics may be the missing link in understanding longstanding questions about ice ages, based on the findings of the research team from UMaine, Columbia University's Lamont-Doherty Earth Observatory, the University of Arizona, and GNS Science in New Zealand, published in Quaternary Science Reviews.

For more than a quarter-century, George Denton, UMaine Libra Professor of Geological Sciences, the journal article's first author, has led research reconstructing the history of mountain glaciers in the Southern Hemisphere. In the late 1980s, he and Wallace Broecker, a geochemist at Columbia University, noted that a key question about ice ages remained unresolved -- the link between ice age climate and the orbital cycles in the length and strength of the Earth's season. Evidence showed that ice age climate changes were synchronous in both polar hemispheres, with rapid transitions from glacial to interglacial global climate conditions. They concluded that existing theories could not adequately account for changes in seasonality, ice sheet size and regional climate.

Mountain glaciers are highly sensitive to climate and well suited to climatic reconstruction, using distinctive moraine deposits that mark the former glacier limits. In the 1990s, Denton led research teams in the mapping and dating of moraine sequences in South America and, more recently, in New Zealand's Southern Alps, with co-author David Barrell, geologist and geomorphologist with the New Zealand government's geoscience research institute, GNS Science.

With advances in isotopic dating of moraines in the mid-2000s, Denton teamed up with Columbia University's Joerg Schaefer, who directs the Cosmogenic Nuclide Laboratory at the Lamont-Doherty Earth Observatory. Together with CU-LDEO colleague and co-author Michael Kaplan, Schaefer, Denton, and UMaine assistant professor and co-author Aaron Putnam have guided a succession of UMaine graduate student field and laboratory projects (including Putnam's Ph.D. work) that have developed a chronology of climate-induced glacier changes in the Southern Alps spanning many tens of thousands of years. The most recent participant in the UMaine-CU partnership is UMaine Ph.D. student and co-author Peter Strand.

Collectively, the UMaine, CU-LDEO and GNS Science partners have worked to create and compile mountain glacier chronologies from New Zealand and South America, producing a comprehensive chronology of glacier extent during and since the last ice age. The team then compared the moraine dating to paleoclimate data worldwide to gain insights into the climate dynamics of ice ages and millennial-scale abrupt climate events. The findings highlight a general global synchronicity of mountain-glacier advance and retreat during the last ice age.

Deep insights into the climate dynamics come from co-author Joellen Russell, climate scientist at the University of Arizona and Thomas R. Brown Distinguished Chair of Integrative Science. Following on her longstanding efforts at modeling the climatic modulation of the westerly winds, she evaluated simulations done as part of the Southern Ocean Model Intercomparison Project, part of the Southern Ocean Carbon and Climate Observations and Modeling initiative. The modeling showed the changes to the southern wind systems have profound consequences for the global heat budget, as monitored by glacier systems.

The "switch" takes its name from Zealandia, a largely submerged continental platform about a third of the size of Australia, with the islands of New Zealand being the largest emergent parts. Zealandia presents a physical impediment to ocean current flow. When the westerly wind belt is farther north, the southward flow of warm ocean water from the tropical Pacific is directed north of the New Zealand landmass (glacial mode). With the wind belt farther south, warm ocean water extends to the south of New Zealand (interglacial mode). Computer modelling shows that global climate effects arise from the latitude at which the westerlies are circulating. A southward shift of the southern westerlies invigorates water circulation in the South Pacific and Southern oceans, and warms the surface ocean waters across much of the globe.

The researchers hypothesize that subtle changes in the Earth's orbit affect the behavior of the Southern Hemisphere westerly winds, and that behavior lies at the heart of global ice age cycles. This perspective is fundamentally different from the long-held view that orbital influences on the extent of Northern Hemisphere continental ice sheets regulate ice age climates. Adding weight to the Zealandia Switch hypothesis is that the Southern Hemisphere westerlies regulate the exchange of carbon dioxide and heat between the ocean and atmosphere, and, thus, exert a further influence on global climate.

"Together with interhemispheric paleoclimate records and with the results of coupled ocean-atmosphere climate modeling, these findings suggest a big, fast and global end to the last ice age in which a southern-sourced warming episode linked the hemispheres," according to the researchers, whose work was funded by the Comer Family Foundation, the Quesada Family Foundation, the National Science Foundation and the New Zealand government.

The last glacial termination was a global warming episode that led to extreme seasonality (winter vs. summer conditions) in northern latitudes by stimulating a flush of meltwater and icebergs into the North Atlantic from adjoining ice sheets. Summer warming led to freshwater influx, resulting in widespread North Atlantic sea ice that caused very cold northern winters and amplified the annual southward shift of the Intertropical Convergence Zone and the monsoonal rain belts. Although this has created an impression of differing temperature responses between the polar hemispheres, the so-called "bipolar seesaw," the researchers suggest this is due to contrasting interregional effects of global warming or cooling. A succession of short-lived, abrupt, episodes of cold northern winters during the last ice age are suggested to have been caused by temporary shifts of the Zealandia Switch mechanism.

The southward shift of the Southern Hemisphere westerlies at the termination of the last ice age was accompanied by gradual but sustained release of carbon dioxide from the Southern Ocean, which may have helped to lock the climate system into a warm interglacial mode.

The researchers suggest that the introduction of fossil CO2 into the atmosphere may be reawakening the same dynamics that ended the last ice age, potentially propelling the climate system into a new mode.

"The mapping and dating of mid-latitude Southern Hemisphere mountain-glacier moraines leads us to the view that the latitude and strength of the austral westerlies, and their effect on the tropical/subtropical ocean, particularly in the region spanning the Indo-Pacific Warm Pool and Tasman Sea through to the Southern Ocean, provides an explanation for driving orbital-scale global shifts between glacial and interglacial climatic modes, via the Zealandia Switch mechanism," the research team wrote. "Such behavior of the ocean-atmosphere system may be operative in today's warming world, introducing a distinctly nonlinear mechanism for accelerating global warming due to atmospheric CO2 rise."

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Glaciers and enigmatic stone stripes in the Ethiopian highlands

UNIVERSITY OF BERN

Research News

 

IMAGE: THE UP TO 200 M LONG, 15 M WIDE AND 2 M DEEP SORTED STONE STRIPS ON THE SOUTHERN SANETTI PLATEAU (CA. 3,900 M A.S.L.) WERE PROBABLY FORMED DURING THE... view more 

CREDIT: HEINZ VEIT

As the driver of global atmospheric and ocean circulation, the tropics play a central role in understanding past and future climate change. Both global climate simulations and worldwide ocean temperature reconstructions indicate that the cooling in the tropics during the last cold period, which began about 115,000 years ago, was much weaker than in the temperate zone and the polar regions. The extent to which this general statement also applies to the tropical high mountains of Eastern Africa and elsewhere is, however, doubted on the basis of palaeoclimatic, geological and ecological studies at high elevations.

A research team led by Alexander Groos, Heinz Veit (both from the Institute of Geography) and Naki Akçar (Institute of Geological Sciences) at the University of Bern, in collaboration with colleagues from ETH Zurich, the University of Marburg and the University of Ankara, used the Ethiopian Highlands as a test site to investigate the extent and impact of regional cooling on tropical mountains during the last glacial period. The results have been published in the scientific journals Science Advances and Earth Surface Dynamics.

Formation of plateau and valley glaciers

"The Ethiopian Highlands are currently not covered by ice, despite its elevation of over 4,000 m," explains Groos, who studied the glacial, climatic and landscape history of the Bale and Arsi Mountains in the southern highlands as part of his dissertation. "Moraines and other land forms, however, attest to the fact that these mountains were glaciated during the last cold period," he continues.

Moraine boulders in the Bale and Arsi Mountains were mapped and sampled in the field and later dated using the chlorine isotope "36Cl" to accurately determine the extent and timing of past glaciations. The researchers were in for a surprise: "Our results show that glaciers in the southern Ethiopian Highlands reached their maximum extent between 40,000 and 30,000 years ago," says Groos, "several thousand years earlier than in other mountainous regions in Eastern Africa and worldwide." In total, the glaciers in the southern highlands covered an area of more than 350 km² during their maximum. In addition to the cooling of at least 4 to 6 °C, the extensive volcanic plateaus above 4,000 m favored the development of glaciation in this magnitude.

The researchers gained important insights by comparing the specially reconstructed glacier fluctuations in the Ethiopian Highlands with those of the highest East African mountains and climate archives from the Great African Rift Valley. "The cross-comparisons show that the tropical mountains in Eastern Africa have experienced a more pronounced cooling than the surrounding lowlands," Groos concludes. "Furthermore, the results suggest a nonuniform response by East African glaciers and ice caps to climate changes during the last cold period, which can be attributed to regional differences in precipitation distribution and mountain relief, among other factors," he continues.

CAPTION

Satellite image of the up to 200 m long, 15 m wide and 2 m deep sorted stone stripes on the southern Sanetti Plateau (ca. 3,900 m.a.s.l.). The stone stripes were probably formed during the last glacial period under much cooler conditions and can best be explained by a natural sorting of the stones in the course of the cyclic freezing and thawing of the ground.

CREDIT

Alexander R. Groos / Digital Globe Foundation

The enigma of the stone stripes

During their fieldwork on the central Sanetti Plateau in the Bale Mountains, the researchers also came across gigantic stone stripes (up to 1,000 m long, 15 m wide and 2 m deep) outside the area of the former ice cap. "The existence of these stone stripes on a tropical plateau surprised us, as so-called periglacial landforms of this magnitude were previously only known from the temperate zone and polar regions and are associated with ground temperatures around freezing point," Groos said. However, the average ground temperature on the Sanetti Plateau is currently about 11 °C.

The large boulders and basalt columns that make up the stone stripes originally came from heavily eroded rock formations and volcanic plugs. As things stand, the researchers assume that the stone stripes were formed during the last glacial period through natural sorting of the previously chaotically distributed rocks in the course of the periodic freezing and thawing of the ground near the former ice cap. However, locally this would have required a drop in the mean ground temperature of at least 11 °C and in the mean air temperature of at least 7 °C. Whether this unprecedented cooling is a regional phenomenon or exemplary for the cooling of tropical high mountains during the last glacial period must be shown by future studies from other tropical mountain regions.

CAPTION

Sampling of an erratic boulder on a terminal moraine in the Arsi Mountains, indicating the extent of valley glaciers during the last glacial period. The rock sample was then processed at the University of Bern and dated at ETH Zurich to timing of the glacial stages.

CREDIT

Serdar Yesilyurt

Evaluating the rehabilitation of an old mine waste rock pile

UNIVERSITY OF SEVILLE

Research News

 

IMAGE: RESULT OF THE WASTE ROCK PILE REHABILITATION view more 

CREDIT: UNIVERSIDAD DE SEVILLA

The Cabeza de los Gatos waste rock pile, left from mining activities in the town of Tharsis (Huelva), underwent a rehabilitation process consisting of remodelling the slope of the pile, applying liming materials and then a layer of soil. Finally, trees and shrubs typical of the area were planted and a hydroseeding with a mixture of shrub and herbaceous seeds was applied. Twelve years later, a study led by researchers from IRNAS-CSIC, in collaboration with Sabina Rossini Oliva, a researcher from the University of Seville and the Environment and Water Agency of Andalusia (AMAYA), has proven the effectiveness of this sort of rehabilitation.

"The results obtained show that the steps taken were successful. Now, twelve years later, woody vegetation covers the upper part of the rehabilitated area and provides a green visual landscape for the inhabitants of the village. Furthermore, it has been proved that the aerial part of the vegetation growing on this upper part does not present significant levels of potentially toxic trace elements," Rossini explained.

In contrast, experts point out that the lower part of the slope is almost devoid of vegetation. Moreover, some of the plants growing at the base of the slope, such as gum rockrose (Cistus ladanifer), have cadmium concentrations exceeding the maximum tolerable level for animals, meaning they represent a toxicity risk for livestock.

"Our view is that this anomaly stems from acidic drainage from the pile which has caused a sharp drop in soil pH at the bottom of the slope. This has increased the presence of potentially toxic trace elements and thus their accumulation in plant leaves. This adverse effect has manifested as lower vegetation cover," the University of Seville researcher added.

In light of the results obtained, an alternative technique is proposed for the rehabilitation of mine rock waste piles by classifying and selectively managing the mine waste. This technique consists of managing excavation waste and selecting it based on its geochemical properties; separating materials that may generate acid from those that do not. The non-acid-generating waste should then be placed on the outside of the waste rock pile as a protective layer to prevent water contamination. This reduces infiltration rates, seepage and the negative effect of acid drainage from the m

Scientists may have the answer to the ancient mystery of the Antikythera mechanism, after more than a century

National Post Staff 3/12/2021


For more than 100 years, scientists have deliberated the mystery behind the ancient Antikythera mechanism, a 2,000 year old Greek astronomical calculator with the ability to exhibit the movement of the universe, including five known planets and predict the phases of the moon and the solar and lunar eclipses.

© Provided by National Post A digital model of how the calculator may have looked and worked in the first century B.C.

Currently only a third of the device — often defined as the world’s first analogue computer — remains in a collection of 82 battered fragments, including 30 corroded bronze gearwheels, further baffling scholars.


Researchers also don’t know why the Antikythera mechanism was built. It could have been a toy, or a teaching tool, they posited.

“Although metal is precious, and so would have been recycled, it is odd that nothing remotely similar has been found or dug up,” Wojcik said. “If they had the tech to make the Antikythera mechanism, why did they not extend this tech to devising other machines, such as clocks?”

However researchers at the University College of London believe they may have finally cracked the code and hope to prove it by building a replica using modern machinery to test their theory. “We believe that our reconstruction fits all the evidence that scientists have gleaned from the extant remains to date,” Adam Wojcik, a materials scientist at UCL, told The Guardian .

If their theory is correct, then they hope to rebuild the mechanism using a technique from antiquity, they wrote in a paper published by science journal Nature .

The calculator first came to light in 1901 after it was recovered by sponge divers looking for treasures within an archaic ship sunken off the coast of Antikythera, a Greek island. Scholars believe the ship sank during a storm in the first century BC while passing between Crete and the Peloponnese while en route to Rome from Asia Minor.

The device is heavily corroded, but scholars examining it noticed several inscriptions on the mechanism, which provide a kind of user’s manual to operating the calculator. It also included more than 30 bronze gearwheels connected to dials and pointers.

The team believe that the device may have displayed the movement of the sun, moon and the planets Mercury, Venus, Mars, Jupiter and Saturn on concentric rings. However, as the calculator assumes that the sun and planets revolve around the Earth, the planets’ paths are much more difficult to recreate than if the Sun was at the centre.

They also propose adding a hypothetical feature, called the ‘Dragon Hand’ that indicates when eclipses would happen, to replace a similar hand once used by the clock. “The way that the Saros Dial on the Back Plate predicts eclipses essentially involves the lunar nodes , but they are not described in the extant inscriptions,” the paper reads. Lunar nodes are where the Moon’s orbit intersects that of the Earth.

The UCL team wrote that it drew on the works of previous scholars and engineers to reconstruct the mechanism, particularly that of Michael Wright.

Wright, a former mechanical engineer at the Science Museum of London, was instrumental in figuring out how most of the mechanism work, enough to build a working replica. Drawing on his work, researchers used inscriptions on the mechanism and a mathematical method described by Parmenides, an ancient Greek philosopher, to design gear arrangements to move planets and other bodies correctly.

Their solution allows nearly all of the mechanism’s gearwheels to fit within a space only 25 mm deep.

Though hopeful, it isn’t clear whether the new model could accurate replicate the workings of the calculator. For one, the concentric rings that constitute the calculator’s display would have to rotate on a set of nested, hollow axles, and researchers aren’t sure how ancient Greeks would have made the mechanism possible without a modern-day lathe (a machining tool used to shape or rotate metal and wood).

“The concentric tubes at the core of the planetarium are where my faith in Greek tech falters, and where the model might also falter,” said Wojcik. “Lathes would be the way today, but we can’t assume they had those for metal.”

Experts recreate a mechanical Cosmos for the world's first computer

UNIVERSITY COLLEGE LONDON

Research News

 

Researchers at UCL have solved a major piece of the puzzle that makes up the ancient Greek astronomical calculator known as the Antikythera Mechanism, a hand-powered mechanical device that was used to predict astronomical events.

Known to many as the world's first analogue computer, the Antikythera Mechanism is the most complex piece of engineering to have survived from the ancient world. The 2,000-year-old device was used to predict the positions of the Sun, Moon and the planets as well as lunar and solar eclipses.

Published in Scientific Reports, the paper from the multidisciplinary UCL Antikythera Research Team reveals a new display of the ancient Greek order of the Universe (Cosmos), within a complex gearing system at the front of the Mechanism.

Lead author Professor Tony Freeth (UCL Mechanical Engineering) explained: "Ours is the first model that conforms to all the physical evidence and matches the descriptions in the scientific inscriptions engraved on the Mechanism itself.

"The Sun, Moon and planets are displayed in an impressive tour de force of ancient Greek brilliance."

The Antikythera Mechanism has generated both fascination and intense controversy since its discovery in a Roman-era shipwreck in 1901 by Greek sponge divers near the small Mediterranean island of Antikythera.

The astronomical calculator is a bronze device that consists of a complex combination of 30 surviving bronze gears used to predict astronomical events, including eclipses, phases of the moon, positions of the planets and even dates of the Olympics.

Whilst great progress has been made over the last century to understand how it worked, studies in 2005 using 3D X-rays and surface imaging enabled researchers to show how the Mechanism predicted eclipses and calculated the variable motion of the Moon.

However, until now, a full understanding of the gearing system at the front of the device has eluded the best efforts of researchers. Only about a third of the Mechanism has survived, and is split into 82 fragments - creating a daunting challenge for the UCL team.

The biggest surviving fragment, known as Fragment A, displays features of bearings, pillars and a block. Another, known as Fragment D, features an unexplained disk, 63-tooth gear and plate.

Previous research had used X-ray data from 2005 to reveal thousands of text characters hidden inside the fragments, unread for nearly 2,000 years. Inscriptions on the back cover include a description of the cosmos display, with the planets moving on rings and indicated by marker beads. It was this display that the team worked to reconstruct.

Two critical numbers in the X-rays of the front cover, of 462 years and 442 years, accurately represent cycles of Venus and Saturn respectively. When observed from Earth, the planets' cycles sometimes reverse their motions against the stars. Experts must track these variable cycles over long time-periods in order to predict their positions.

"The classic astronomy of the first millennium BC originated in Babylon, but nothing in this astronomy suggested how the ancient Greeks found the highly accurate 462-year cycle for Venus and 442-year cycle for Saturn," explained PhD candidate and UCL Antikythera Research Team member Aris Dacanalis.

Using an ancient Greek mathematical method described by the philosopher Parmenides, the UCL team not only explained how the cycles for Venus and Saturn were derived but also managed to recover the cycles of all the other planets, where the evidence was missing.

PhD candidate and team member David Higgon explained: "After considerable struggle, we managed to match the evidence in Fragments A and D to a mechanism for Venus, which exactly models its 462-year planetary period relation, with the 63-tooth gear playing a crucial role."

Professor Freeth added: "The team then created innovative mechanisms for all of the planets that would calculate the new advanced astronomical cycles and minimize the number of gears in the whole system, so that they would fit into the tight spaces available."

"This is a key theoretical advance on how the Cosmos was constructed in the Mechanism," added co-author, Dr Adam Wojcik (UCL Mechanical Engineering). "Now we must prove its feasibility by making it with ancient techniques. A particular challenge will be the system of nested tubes that carried the astronomical outputs."

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The discovery brings the research team a step closer to understanding the full capabilities of the Antikythera Mechanism and how accurately it was able to predict astronomical events. The device is kept at the National Archaeological Museum in Athens.

The UCL Antikythera Research Team is supported by the A.G. Leventis Foundation, Charles Frodsham & Co. and the Worshipful Company of Clockmakers.

The team is led by Dr Adam Wojcik and made up of Professor Tony Freeth, Professor Lindsay MacDonald (UCL CEGE), Dr Myrto Georgakopoulou (UCL Qatar) and PhD candidates David Higgon and Aris Dacanalis (both UCL Mechanical Engineering).

Accurate aging of wild animals thanks to first epigenetic clock for bats

UMD-led research identifies age-related changes to DNA and reveals longevity-related differences between bat species

UNIVERSITY OF MARYLAND

Research News

 

IMAGE: UMD-LED STUDY REVEALED AGE-RELATED CHANGES TO THE DNA OF BATS RELATED TO LONGEVITY. CLOCKWISE FROM TOP LEFT: COMMON VAMPIRE BAT, (G. WILKINSON), GREATER HORSESHOE BAT, RHINOLOPHUS FERRUMEQUINUM (G. JONES), VELVETY... view more 

CREDIT: G. WILKINSON, G. JONES, S. PUECHMAILLE, M. TSCHAPKA

A new study led by University of Maryland and UCLA researchers found that DNA from tissue samples can be used to accurately predict the age of bats in the wild. The study also showed age-related changes to the DNA of long-lived species are different from those in short-lived species, especially in regions of the genome near genes associated with cancer and immunity. This work provides new insight into causes of age-related declines.

This is the first research paper to show that animals in the wild can be accurately aged using an epigenetic clock, which predicts age based on specific changes to DNA. This work provides a new tool for biologists studying animals in the wild. In addition, the results provide insight into possible mechanisms behind the exceptional longevity of many bat species. The study appears in the March 12, 2021, issue of the journal Nature Communications.

"We hoped that these epigenetic changes would be predictive of age," said Gerald Wilkinson, a professor of biology at UMD and co-lead author of the paper. "But now we have the data to show that instead of having to follow animals over their lifetime to be sure of their age, you can just go out and take a tiny sample of an individual in the wild and be able to know its age, which allows us to ask all kinds of questions we couldn't before."

The researchers looked at DNA from 712 bats of known age, representing 26 species, to find changes in DNA methylation at sites in the genome known to be associated with aging. DNA methylation is a process that switches genes off. It occurs throughout development and is an important regulator for cells. Overall, methylation tends to decrease throughout the genome with age. Using machine learning to find patterns in the data, the researchers found that they could estimate a bat's age to within a year based on changes in methylation at 160 sites in the genome. The data also revealed that very long-lived bat species exhibit less change in methylation overall as they age than shorter-lived bats.

Wilkinson and his team then analyzed the genomes of four bat species--three long-lived and one short-lived--to identify the specific genes present in those regions of the genome where age-related differences in methylation correlated with longevity. They found specific sites on the genome where methylation was more likely to increase rather than decrease with age in the short-lived bats, but not in long-lived bats, and that those sites were located near 57 genes that mutate frequently in cancerous tumors and 195 genes involved in immunity.

"What's really interesting is that the sites where we found methylation increasing with age in the short-lived bats are near genes that have been shown to be involved in tumorigenesis--cancer--and immune response," Wilkinson said. "This suggests there may be something to look at in these regions regarding mechanisms responsible for longevity."

Wilkinson said analyzing methylation may provide insight into many age-related differences between species and lead to a better understanding of the causes for age-related declines across many species.

"Bats live a long time, and yet their hearing doesn't decay with age, the way ours does," he said. "You could use this method to see whether there are differences in methylation that are associated with hearing. There are all kinds of questions like this we can ask now."

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In addition to Wilkinson, co-authors of the paper from UMD include current postdoctoral associate Danielle M. Adams (Ph.D. '19, biological sciences) and former graduate students Bryan Arnold (Ph.D. '11, behavior, ecology, evolution, and systematics), now an associate professor at Illinois College; and Gerald Carter (Ph.D., '15, biology), now an assistant professor at Ohio State University; Edward Hurme (Ph.D. '20, biological sciences), now a postdoctoral associate at the University of Konstanz in Germany.

The research paper, "DNA methylation predicts age and provides insight into exceptional longevity of bats," was published in the March 12, 2021, issue of Nature Communications.

This work was supported by a grant from the Paul G. Allen Frontiers Group. The content of this article does not necessarily reflect the view of this organization.

Media Relations Contact: Kimbra Cutlip, 301-405-9463, kcutlip@umd.edu

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About the College of Computer, Mathematical, and Natural Sciences

The College of Computer, Mathematical, and Natural Sciences at the University of Maryland educates more than 9,000 future scientific leaders in its undergraduate and graduate programs each year. The college's 10 departments and more than a dozen interdisciplinary research centers foster scientific discovery with annual sponsored research funding exceeding $200 million.

'Magical' fire suppressant kills zombie fires 40% faster than water alone

ZOMBIE FIRES BURNING FOR HUNDREDS OF YEARS UNDERGROUND 

IMPERIAL COLLEGE LONDON

Research News

 

The researchers say this is a big step in tackling smouldering peat fires, which are the largest fires on Earth. They ignite very easily, are notoriously difficult to put out, and release up to 100 times more carbon into the atmosphere than flaming fires, contributing to climate change.

The fires, known as 'zombie fires' for their ability to hide and smoulder underground and then reanimate as new flames days or weeks after the wildfire had been extinguished, are prevalent in regions like Southeast Asia, North America, and Siberia.

They are driven by the burning of soils rich in organic content like peat, which is a large natural reservoir of carbon. Worldwide, peat fires account for millions of tonnes of carbon released into the atmosphere each year.

Firefighters currently use millions to billions of litres of water per to tackle a peat fire: The 2008 Evans Road peat fire in the USA consumed 7.5 billion litres of water, and the 2018 Lake Cobrico peat fire in Australia consumed 65 million.

However, when water alone is used to extinguish peat fires, it tends to create a few large channels in the soil, diverting the water from nearby smouldering hotspots where it is most needed. This is partly why they take can so long to be extinguished.

Now, researchers at Imperial College London have combined water with an environmentally friendly fire suppressant that is already used to help extinguish flaming wildfires, to measure its effectiveness against peat fires at different concentrations.

During laboratory experiments at Imperial's HazeLab, they found that adding the suppressant to water helped them put out peat fires nearly twice as fast as using water alone, while using only a third to a half of the usual amount of water.

Lead author Muhammad Agung Santoso of Imperial's Department of Mechanical Engineering said: "The suppressant could enable firefighters to put out peat fires much faster while using between a third to half of the amount of water. This could be critical in ending pollution-related deaths, devastation of local communities, and environmental damage caused by these fires."

The results are published in International Journal of Wildland Fire.

IT IS AN ORGANIC SURFACTANT 

The suppressant, also known as a 'wetting agent', increases the penetrating properties of liquids like water by reducing their surface tension. This agent is made from plant matter and is biodegradable so it doesn't harm the environment. 

The researchers mixed the wetting agent with water at three concentrations: 0% (pure water), 1% (low concentration), and 5% (high concentration). They used each concentration on a laboratory peat fire with varying rates of flow between 0.3 and 18 litres per hour.

They found that the suppressant reduced the surface tension of the liquid, which made it less likely to create large channels and instead flow uniformly through the soil. Low-concentration solutions reduced the average fire suppression time by 39%, and the high concentration solution reduced it by 26% but more consistently. The average volume of liquid needed for suppression was 5.7 litres per kilogram of burning peat, regardless of flow rates or suppressant.

They also learned that the agent acts thermally and not chemically: it encapsulates the fire to bring down the temperature and remove the 'heat' element from the fire triangle. The other two essential elements for fire are oxygen and fuel.

Senior author Professor Guillermo Rein, Head of Hazelab at Imperial's Department of Mechanical Engineering, said: "Fighting peat fires uses an incredible amount of work, time and water, and this biodegradable wetting agent could help everybody: fire brigades, communities and the planet. This magical suppressant could make it easier to put zombie fires to rest for good."

The results provide a better understanding of the suppression mechanism of peat fires and could help to improve firefighting and mitigation strategies. The researchers are now looking to replicate their findings in controlled peat fires outside the lab in real peatlands.

This research was funded by the European Research Council and the Indonesia Endowment Fund for Education.

"Laboratory study on the suppression of smouldering peat wildfires: effects of flow rate and wetting agent" by Muhammad A. Santoso, Wuquan Cui, Hafiz M. F. Amin, Eirik G. Christensen, Yulianto S. Nugroho, and Guillermo Rein. Published 9 March 2021 in International Journal of Wildland Fire.

   

Research discovers malaria devastating humans far earlier than expected

UNIVERSITY OF OTAGO

Research News

 

New bioarchaeological research shows malaria has threatened human communities for more than 7000 years, earlier than when the onset of farming was thought to have sparked its devastating arrival.

Lead author Dr Melandri Vlok from the Department of Anatomy, University of Otago, says this ground-breaking research, published today in Scientific Reports, changes the entire understanding of the relationship humans have had with malaria, still one of the deadliest diseases in the world.

"Until now we've believed malaria became a global threat to humans when we turned to farming, but our research shows in at least Southeast Asia this disease was a threat to human groups well before that.

"This research providing a new cornerstone of malaria's evolution with humans is a great achievement by the entire team," Dr Vlok says.

Still a serious health issue, as recently as 2019 the World Health Organization reported an estimated 229 million cases of malaria around the world, with 67 per cent of malaria deaths in children under the age of 5 years.

While malaria is invisible in the archaeological record, the disease has changed the evolutionary history of human groups causing consequences visible in prehistoric skeletons. Certain genetic mutations can lead to the inheritance of Thalassemia, a devasting genetic disease that in its milder form provides some protection against malaria.

Deep in humanity's past, the genes for malaria became more common in Southeast Asia and the Pacific where it remains a threat, but up until now the origin of malaria has not been pinpointed. This research has identified thalassemia in an ancient hunter-gatherer archaeological site from Vietnam dated to approximately 7000 years ago, thousands of years before the transition to farming in the region.

In some parts of the world, slashing and burning in agricultural practice would have created pools of stagnant water attracting mosquitos carrying malaria, but in Southeast Asia these mosquitos are common forest dwellers exposing humans to the disease long before agriculture was adopted.

The study Forager and farmer evolutionary adaptations to malaria evidenced by 7000 years of thalassemia in Southeast Asia is a result of combined efforts from years of investigation by a team of researchers led by Professor Marc Oxenham (currently at the University of Aberdeen) and including researchers from University of Otago, the Australian National University (ANU), James Cook University, Vietnam Institute of Archaeology and Sapporo Medical University.

The research is the first of its kind to use microscopic techniques to investigate changes in bone tissue to identify thalassemia. In 2015, Professor Hallie Buckley from the University of Otago noticed changes in the bone of hunter-gatherers that made her suspicious that thalassemia might be the cause, but the bones were too poorly preserved to be certain. Professor Buckley called in microscopic bone expert Dr Justyna Miszkiewicz of ANU to investigate. Under the microscope, the ancient samples from Vietnam showed evidence for abnormal porosity mirroring modern-day bone loss complications in thalassemic patients.

At the same time, Dr Vlok, completing her doctoral research in Vietnam, found changes in the bones excavated in a 4000-year-old agricultural site in the same region as the 7000-year-old hunter-gatherer site. The combined research suggests a long history of evolutionary changes to malaria in Southeast Asia which continues today.

"A lot of pieces came together, then there was a startling moment of realisation that malaria was present and problematic for these people all those years ago, and a lot earlier than we've known about until now," Dr Vlok adds.

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