понедельник, 7 октября 2019 г.

68 early Byzantine gold coins found in northwest Turkey

Archaeologists have discovered 68 gold coins, dating back 1,500 years to the early Byzantine era, in the village of Gülpınar in northwestern Çanakkale province.











68 early Byzantine gold coins found in northwest Turkey
Credit: DHA

The small treasure was found on August 7 at the bottom of a wall of a Byzantine house during excavations in Ayvacık district.


Speaking to the press to announce the remarkable find, Prof. Coşkun Özgünel said they had determined that the coins belonged to the eras of Justinian I and II, and were from the years 550-575 AD. Some gold coins contained a figure of Emperor Justinian I holding a globe with a cross on it and a shield.











68 early Byzantine gold coins found in northwest Turkey
Credit: DHA

The discovery of the coins, coupled with the findings from ongoing excavations in and around the Temple of Apollon Smintheion, showed that the area was still active during the early Byzantine era.
Pointing out that excavations in the village have been continuing since the 80s, Özgünel said: «The significance of the treasure found this year is that it is of a specific period. It belongs to the second half of the 5th century, which roughly translates to around 550-575.»











68 early Byzantine gold coins found in northwest Turkey
Credit: DHA

«As you know, gold is not a material that rusts like bronze. We were covered in mud because the area got flooded due to rainfall. After cleaning the area, we found 68 gold coins large and small.»


Özgünel said that although the coins ranged in sizes and were of different weight in grams, they had very little differences overall.











68 early Byzantine gold coins found in northwest Turkey
Credit: DHA

«We’ve called this a treasure but it is actually an accumulation, a savings of some sort. The owner of these coins certainly had worries about his/her future, hence was saving up all this gold,» he added.


Source: Daily Sabah [September 30, 2019]



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Scientists quantify global volcanic CO2 venting; estimate total carbon on Earth

Volcanoes, colliding and spreading continental and oceanic plates, and other phenomena re-studied with innovative high-tech tools, provide important fresh insights to Earth’s innermost workings, scientists say.











Scientists quantify global volcanic CO2 venting; estimate total carbon on Earth
Gas sampling at Lastarria Volcano (northern Chile) during the Trail by Fire expedition
[Credit: Yves Moussallam, Lamont Doherty Earth Observatory]

Preparing to summarize and celebrate the 10-year Deep Carbon Observatory program at the National Academy of Sciences, Washington DC, Oct. 24-26, DCO’s 500-member Reservoirs and Fluxes team today outlined several key findings that span time from the present to billions of years past; from Earth’s core to its atmosphere, and in size from single volcanoes to the five continents.


Among many wide-ranging findings, outlined and summarized in a series of papers published in the journal Elements:


— Just two-tenths of 1% of Earth’s total carbon — about 43,500 gigatonnes (Gt) — is above surface in the oceans, on land, and in the atmosphere. The rest is subsurface, including the crust, mantle and core — an estimated 1.85 billion Gt in all


— CO2 out-gassed to the atmosphere and oceans today from volcanoes and other magmatically active regions is estimated at 280 to 360 million tonnes (0.28 to 0.36 Gt) per year, including that released into the oceans from mid-ocean ridges


— Humanity’s annual carbon emissions through the burning of fossil fuels and forests, etc., are 40 to 100 times greater than all volcanic emissions


— Earth’s deep carbon cycle through deep time reveals balanced, long-term stability of atmospheric CO2, punctuated by large disturbances, including immense, catastrophic releases of magma that occurred at least five times in the past 500 million years. During these events, huge volumes of carbon were outgassed, leading to a warmer atmosphere, acidified oceans. and mass extinctions


— Similarly, a giant meteor impact 66 million years ago, the Chicxulub bolide strike on Mexico’s Yucatan peninsula, released between 425 and 1,400 Gt of CO2, rapidly warmed the planet and coincided with the mass (>75%) extinction of plants and animals — including the dinosaurs. Over the past 100 years, emissions from anthropogenic activities such as burning fossil fuels have been 40 to 100 times greater than our planet’s geologic carbon emissions


— A shift in the composition of volcanic gases from smelly (akin to burnt matches) sulphur dioxide (SO2) to a gas richer in odorless, colorless CO2 can be sniffed out by monitoring stations or drones to forewarn of an eruption — sometimes hours, sometimes months in advance. Eruption early warning systems with real-time monitoring are moving ahead to exploit the CO2 to SO2 ratio discovery, first recognized with certainty in 2014


Says DCO scientist Marie Edmonds of the University of Cambridge, UK: «Carbon, the basis of all life and the energy source vital to humanity, moves through this planet from its mantle to the atmosphere. To secure a sustainable future, it is of utmost importance that we understand Earth’s entire carbon cycle.»


«Key to unraveling the planet’s natural carbon cycle is quantifying how much carbon there is and where, how much moves — the flux — and how quickly, from Deep Earth reservoirs to the surface and back again.»


Adds colleague Tobias Fischer of the University of New Mexico, USA: «The Deep Carbon Observatory has advanced understanding of the inner workings of Earth. Its collective body of more than 1500 publications has not only increased what is known but established limits to what is knowable, and perhaps unknowable.»


«While we celebrate progress, we underline that deep Earth remains a highly unpredictable scientific frontier; we have truly only started to dent current boundaries of our knowledge.»


How Much Carbon does Earth Contain?


Scientists have long known that carbon inside Earth exists as a diverse array of solids, fluids, and gases. Some of these materials involve combinations of carbon with oxygen (e.g. carbon dioxide), with iron (e.g., carbides), with hydrogen (e.g., kerogen, coal, petroleum, and methane), and other elements (e.g., silicon, sulfur, and nitrogen), in addition to elemental carbon (e.g., graphite and diamond).











Scientists quantify global volcanic CO2 venting; estimate total carbon on Earth
Histograms of carbon influx (positive values) and outflux (negative values) to the atmosphere and the oceans. Units are
in Pg C/y. (A) Carbon fluxes based on steady state models. Abbreviations: MOR = mid ocean ridge; org carbon = organic
carbon. (B) Carbon fluxes as a result of large-scale perturbations to the carbon cycle. Total outgassing refers to events
 listed in Figure 2A; anthropogenic is human contributions; Chicxulub (Mexico) refers to the end-Cretaceous asteroid
impact and resultant mass extinction; average LIP refers to the input from large igneous provinces. Data from
Kawaragi et al. (2009), Lee et al. (2019) and Black and Gibson (2019) [Credit: Deep Carbon Observatory]

Deep Carbon Observatory scientists underline that knowledge of total carbon in lower mantle and core is still speculative and the numbers are sure to evolve in accuracy as research continues. That said, experts (notably Lee et al., 2019) estimate reservoirs of carbon on Earth as follows:


By the numbers: Best current estimates, carbon on Earth


1.85 billion gigatonnes (1.85 x 1 billion x 1 billion tonnes): Total carbon on Earth


Breakdown:


— 1,845,000,000 (1.845 billion) Gt: total carbon below surface


— 1,500,000,000 (1.5 billion) Gt: Carbon in the lower mantle:
— 315,000,000 (0.315 billion) Gt: Carbon in the continental and oceanic lithospheres


— 30,000,000 (0.03 billion) Gt: Carbon in the upper mantle


— 43,500 Gt: total carbon above surface — in the oceans, on land, and in the atmosphere (2/10ths of 1% of Earth’s total carbon)


— 37,000 Gt: Carbon in the deep ocean (85.1% of all above surface carbon)


— 3,000 Gt: Carbon in marine sediments (6.9%)


— 2,000 Gt: Carbon in the terrestrial biosphere (4.6%)


— 900 Gt Carbon in the surface ocean (2%)


— 590 Gt: Carbon in the atmosphere (1.4%)


Release of CO2 from volcanoes


Earth’s total annual out-gassing of CO2 via volcanoes and through other geological processes such as the heating of limestone in mountain belts is newly estimated by DCO experts at roughly 300 to 400 million metric tonnes (0.3 to 0.4 Gt).


Volcanoes and volcanic regions alone outgas an estimated 280-360 million tonnes (0.28 to 0.36 Gt) of CO2 per year. This includes the CO2 contribution from active volcanic vents, from the diffuse, widespread release of CO2 through soils, faults, and fractures in volcanic regions, volcanic lakes, and from the mid-ocean ridge system.


In many world regions, tectonic outgassing (emissions from mountain belts and other plate boundaries), particularly in cool night temperatures, can cause dangerous levels of CO2 close to the ground — enough to suffocate livestock.


According to DCO researchers, with rare exceptions over millions of years the quantity of carbon released from Earth’s mantle has been in relative balance with the quantity returned through the downward subduction of tectonic plates and other processes.


Carbon catastrophes


While the volume of carbon buried through subduction and what’s released from volcanoes and tectonic fractures are normally in steady state, about four times over the past 500 million years this balance has been upended by the emergence of large volcanic events — 1 million or more square kilometers (the area of Canada) of magma released within a timeframe of a few tens of thousands of years up to 1 million years.


These «large igneous provinces» degassed enormous volumes of carbon (estimated at up to 30,000 Gt — equal to about 70% of the estimated 43,500 Gt of carbon above surface today).


Carbon cycle imbalance can cause rapid global warming, changes to the silicate weathering rate, changes to the hydrologic cycle, and overall rapid habitat changes that can cause mass extinction as the Earth rebalances itself.


Similar carbon catastrophes have been caused by asteroids / meteors (bolides), such as the massive Chixculub impact in the Yucatan area of Central America 65 million years ago — an event to which extinction of the dinosaurs and most other plants and animals of the time has been attributed.


According to Australian researchers Balz Kamber and Joseph Petrus: «The Chicxulub event … greatly disrupted the budget of climate-active gases in the atmosphere, leading to short-term abrupt cooling and medium-term strong warming.»


«Thus, some large bolide impacts are comparable to those observed in the Anthropocene in terms of rapidly disrupting the C (carbon) cycle and potentially exceeding a critical size of perturbation.»


Wiring up volcanoes


DCO experts estimate that about 400 of the 1500 volcanoes active since the last Ice Age 11,700 years ago are venting CO2 today. Another 670 could be producing diffuse emissions, with 102 already documented. Of these, 22 ancient volcanoes that have not erupted since Pleistocene epoch (2.5 million years ago to the Ice Age) are outgassing. Thus all volcanoes, the young and very old, may be emitting CO2.











Scientists quantify global volcanic CO2 venting; estimate total carbon on Earth
Year-round monitoring at five volcanoes revealed that the level of carbon dioxide relative to sulfur dioxide in volcanic
gases systematically changes in the hours to months before an eruption. Here Deep Carbon Observatory volcanologist
Brendan McCormick installs a DECADE (Deep Earth Carbon DEgassing) subgroup MultiGAS monitoring device
 at Rabaul Volcano, Papua New Guinea [Credit: Emma Liu, University of Cambridge]

Today’s CO2, sulphur dioxide and hydrogen sulphide emissions rates are now quantified for many of the world’s most active volcanoes thanks in part to the development of miniature, durable, inexpensive instruments.


And several volcanoes have been wired up with permanent gas instrument monitoring stations to obtain real time data readings, improving monitoring by governments and universities in the USA, Italy, Costa Rica, and elsewhere. About 30 collaboratively operated gas-monitoring stations on volcanoes across five continents now exist, which continually monitor emissions.


Pioneered by scientists with DCO’s DECADE (Deep Earth Carbon DEgassing) subgroup, the technologies and installations have helped revolutionize data collection within inaccessible or dangerous volcanic places. The data obtained are combined with readings from long-established ground and satellite systems.


Recent research has revealed the number of volcanoes thought to be out-gassing measurable amounts of CO2 today. Estimated at 150 in 2013, DECADE researchers confirm that more than 200 volcanic systems emitted measurable volumes of CO2 between the years 2005 and 2017. Of these, several super-regions of diffuse degassing have been documented (e.g., Yellowstone, USA, the East African Rift, Africa, and the Technong volcanic province in China, to name a few). Diffuse degassing is now recognized as a CO2 source comparable to active volcanic vents.


Among the DCO’s legacies: a new database (http://www.magadb.net) to capture information on CO2 fluxes from volcanic and non-volcanic sources around the world.


Volcanic whispers: Changes in ratio of vented SO2 to CO2 can forewarn of eruptions


Research at a growing number of well-monitored volcanoes worldwide has provided important new insight about the timing of eruptions relative to the composition of volcanic outgassing.


Year-round monitoring at five volcanoes revealed that the level of carbon dioxide relative to sulfur dioxide in volcanic gases systematically changes in the hours to months before an eruption. Volcanoes where such patterns have been documented include Poas (Costa Rica), Etna and Stromboli (Italy), Villarica (Chile), and Masaya (Nicaragua). (See also http://bit.ly/2Ssk2UN).


Likewise the CO2 to SO2 ratio changed dramatically months to years prior to large eruptions at Kilauea (Hawaii) and Redoubt Volcano (Alaska), in the USA, suggesting that monitoring gas composition, often in invisible plumes, offers a new eruption forecasting tool that, in some cases, precedes increases in volcano seismicity or ground deformation.


Source Deep Carbon Observatory [October 01, 2019]



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250-million-year-old evolutionary remnants seen in muscles of human embryos

A team of evolutionary biologists, led by Dr. Rui Diogo at Howard University, USA, and writing in the journal Development, have demonstrated that numerous atavistic limb muscles — known to be present in many limbed animals but usually absent in adult humans — are actually formed during early human development and then lost prior to birth. Strikingly, some of these muscles, such as the dorsometacarpales shown in the picture, disappeared from our adult ancestors more than 250 million years ago, during the transition from synapsid reptiles to mammals.











250-million-year-old evolutionary remnants seen in muscles of human embryos
Dorsal view of the left hand of a 10-week old human embryo. The dorsometacarpales
are highlighted: these muscles (like others described in this study) are present in adults
of many other limbed animals, while in humans they normally disappear or become
fused with other muscles before birth [Credit: Rui Diogo,
Natalia Siomava and Yorick Gitton]

Also remarkably, in both the hand and the foot, of the 30 muscles formed at about 7 weeks of gestation one third will become fused or completely absent by about 13 weeks of gestation. This dramatic decrease parallels what happened in evolution and deconstructs the myth that in both our evolution and prenatal development we tend to become more complex, with more anatomical structures such as muscles being continuously formed by the splitting of earlier muscles.


These findings offer new insights into how our arms and legs evolved from our ancestors’, and also about human variations and pathologies, as atavistic muscles are often found either as rare variations in the common human population or as anomalies found in humans born with congenital malformations.


Since Darwin proposed his evolutionary theory, scientists have argued that the occurrence of atavistic structures (anatomical structures lost in the evolution of a certain group of organisms that can be present in their embryos or reappear in adults as variations or anomalies) strongly supports the idea that species change over time from a common ancestor through «descent with modification».


For example, ostriches and other flightless birds have vestigial wings, while whales, dolphins and porpoises lack hind limbs but their embryos initiate and then abort hind limb development. Similarly, temporary small tail-like structures are found in human embryos and the remnant of the lost ancestral tail is retained as our coccyx. Researchers have also suggested that atavistic muscles and bones can also be seen in human embryos, but it has been difficult to visualize these structures clearly, and the images that appear in modern textbooks are mainly based on decades old analyses.


This is changing with development of new technology that provides high-quality 3D images of human embryos and fetuses. In the new study the authors have used these images to produce the first detailed analysis of the development of human arm and leg muscles. The unprecedented resolution offered by the 3D images reveals the transient presence of several of such atavistic muscles.


Dr. Diogo said: «It used to be that we had more understanding of the early development of fishes, frogs, chicken and mice than in our own species, but these new techniques allow us to see human development in much greater detail. What is fascinating is that we observed various muscles that have never been described in human prenatal development, and that some of these atavistic muscles were seen even in 11.5-weeks old fetuses, which is strikingly late for developmental atavisms «.


He further added: «Interestingly, some of the atavistic muscles are found on rare occasions in adults, either as anatomical variations without any noticeable effect for the healthy individual, or as the result of congenital malformations. This reinforces the idea that both muscle variations and pathologies can be related to delayed or arrested embryonic development, in this case perhaps a delay or decrease of muscle apoptosis, and helps to explain why these muscles are occasionally found in adult people. It provides a fascinating, powerful example of evolution at play.»


Source: The Company of Biologists [October 01, 2019]



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Understanding the genomic signature of coevolution

In a recent study published in Science Advances, researchers from Germany, Switzerland, China and the United Kingdom demonstrate that molecular evolution during species interactions is shaped by both eco-evolutionary feedback dynamics and interspecific differences in how genetic diversity is generated and maintained.











Understanding the genomic signature of coevolution
Algal host cell with attached virus particles [Credit: Lutz Becks]

«Species interactions and coevolution are integral to ecological communities,» explains Professor Lutz Becks, Professor of Limnology at the University of Konstanz and main author of the study alongside Dr. Philine Feulner from the Swiss Federal Institute of Aquatic Science and Technology. «Recent experimental studies on molecular evolution in host-virus systems show that coevolution has a significant impact on molecular evolution, host adaptation and diversification as well as speciation. The idea that host and virus adapt to each other by turns has been taken for a well-established fact for a long time,» explains Lutz Becks.


«Typically, after one round of resistance evolution—i.e. the point in time when the host evolves resistance to the parasite through a mutation and the parasite cannot infect and reproduce anymore—you would expect that the host population consists of only the resistant type. As mutations are rare, we always assumed that there is a long period after the resistance evolution during which there is not much diversity at all. However, what we have found in this study is that things are much more complicated than that. Diversity does in fact make a rather striking comeback within a very short period of time.»


The researchers believe this to be due to the interplay between changes in selection—once the host has evolved resistance to the virus, the virus can no longer exert selection pressure—and population growth. Each new mutation after resistance evolution, even if it does not have an effect, increases in frequency because the host population at the same time rapidly expands in size, which in turn generates sustainable diversity. «This is new,» says Lutz Becks. «We were really surprised by the speed of these processes and by how well we were able to track them.»


The approach adopted in this study can best be described as experimental evolution, as Lutz Becks elaborates: «We create certain conditions by introducing microorganisms to an experimental environment and then study how properties of individuals within the populations change over time. By doing this, we are able to not only study one point in time, but to track the entire process over an extended period of time and even go back in order to compare different states with each other.


In other words, we can confront a past state of the host with a virus state of the future, which provides us a fantastic opportunity for identifying evolutionary changes such as resistance evolution in the host or a counter adaptation in the virus.» The experiment carried out for this study involved approximately 100 generations of hosts over a period of 100 days, allowing the researchers to track genomic, phenotypic and population size changes of the host and virus populations by gaining temporally resolved information on both.


The model system used involved Chlorella variabilis algae (host) and the giant virus Paramecium bursaria Chlorella virus 1 (PBCV-1), both of which reproduce exclusively asexually. Lutz Becks: «Typically, what one does is to take a sample, look at how much or little diversity there is and then interpret the results according to one of the well-established patterns for coevolution, which are traditionally placed on a spectrum between two extremes: the so-called «Arms Race dynamics’ and the «Fluctuating-Selection dynamics'».


For the purposes of their study, the researchers investigated a number of time points: «Looking at a point in time shortly after resistance evolution, there shouldn’t be anything happening until the virus counter adapts. However, what we observed was that there was a lot of activity within the host population, involving the build-up of a much higher diversity than anticipated.» By linking these changes in genetic diversity to changes in population size and the resistance and infectivity evolution, the researchers were able to prove that the build-up of diversity was the result of an eco-evolutionary feedback, where rapid evolution and ecological changes directly affect each other.


However, as the study also clearly demonstrates, the same cannot be said for the virus, for which the researchers observed the expected pattern of low diversity after a round of infectiveness evolution. They believe that this has to do with the organisms themselves, as Lutz Becks explains: «The host has a relatively large genome of 46 Megabase pairs (Mbp), which is probably much more flexible than the smaller genome of the virus, which is estimated to consist of only 330 Kilobase pairs (kbp). Size counts insofar as any mutation in the virus can have a negative impact, which means that it will not become prevalent.» This suggests that differences in genome architecture result in distinctly different dynamics of molecular evolution between these two coevolving species.


The researchers expect that a wider recognition of the various ways by which ecological and evolutionary change can affect each other will be essential to unlocking the genomic signature of evolution during species interactions and to understanding the mode, pace and predictability of evolution in natural communities.


Source: University of Konstanz [October 02, 2019]



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Microscopic evidence sheds light on the disappearance of the world’s largest...

Understanding the causes and consequences of Late Quaternary megafaunal extinctions is increasingly important in a world of growing human populations and climate change. A new review, led by scholars at the Bernice Pauahi Bishop Museum and the Max Planck Institute for the Science of Human History, highlights the role that cutting-edge scientific methods can play in broadening the discussions about megafaunal extinction and enabling more localized insights into ecosystems and species-specific responses to climate change and human activities.











Microscopic evidence sheds light on the disappearance of the world's largest mammals
Localized, species-specific understandings of past megafaunal extinctions can help inform
today’s conservation challenges [Credit: Annette Gunzel, MPI-SHH]

The disappearance of many of the world’s largest mammal species occurred around the same time that two other major transformations in Earth’s history were unfolding: dramatic climatic change at the Pleistocene-Holocene boundary (c. 10,000 B.P.) and the dispersal of Homo sapiens to new continents. Untangling the role each of these played in Late Quaternary megafaunal extinctions has been the subject of intense scholarly debate for decades. However, recent advances in archaeological and paleontological science methods have helped demonstrate that megafaunal extinctions are more complex than any single humans-versus-climate answer can provide.
The new article, published in BioScience, emphasizes contributions from five different approaches: radiocarbon dating, stable isotope analysis, ancient DNA, ancient proteins, and microscopy. These techniques can offer robust, high-resolution insights into climate change and extinction chronologies, past habitat transformations, ecological relationships, and species diet and ranging. Especially when used in combination, these advanced methods offer unprecedented levels of detail that can help to better understand causes of extinctions in the past, which can then be applied to contemporary animal management aims, including risk assessments and rewilding efforts.











Microscopic evidence sheds light on the disappearance of the world's largest mammals
New laboratory methods provide detailed insights into the timing and causes of past megafaunal extinctions
[Credit: Michelle O’Reilly, MPI-SHH]

The review is an international and multidisciplinary collaboration between leading experts in megafaunal extinction research and emerging laboratory science methods. «When we started this collaboration, we were worried that we’d never get everyone to see eye-to-eye on megafaunal extinctions,» says Jillian Swift, lead author and archaeologist at the Bernice Pauahi Bishop Museum. «But it was easy to agree on the urgency of understanding deep-time human impacts to Earth systems, so that we can continue to make informed conservation decisions for our future.»
«Approaches to extinctions of ‘megafauna’ in the past are often based on sweeping narratives that assume that all species are equally vulnerable to external threats such as environmental change and human hunting,» says Patrick Roberts, of the Department of Archaeology, Max Planck Institute for the Science of Human History and co-author on the study. «Archaeological science methods allow us to get past these generalizations and explore how the diets, demography, and mobility of individual species and populations changed through time, providing a far more complex, and accurate, picture of past ecosystems.»


«We believe that large, multidisciplinary collaborations such as this offer the best way to approach questions of such magnitude as ‘megafaunal extinctions’,» says Nicole Boivin, Director of the Department of Archaeology, Max Planck Institute for the Science of Human History and co-author. «It is only by coming together, from a variety of fields and backgrounds, that we can apply very different expertise and methodologies to build up more detailed understandings of the past that have major, pressing implications for present-day processes and threats.»


Source: Max Planck Institute for the Science of Human History [October 02, 2019]




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New pterosaur discovered in Australia’s outback Queensland

Australian researchers have found a new species of pterosaur in outback Queensland. The pterosaur, a prehistoric flying reptile, lived amongst the dinosaurs which roamed the Winton region around 96 million years ago. The apex aerial predator had a 4-metre wingspan and walked on all four limbs when on land.











New pterosaur discovered in Australia's outback Queensland
Artist’s impression of what the newly discovered pterosaur Ferrodraco lentoni looked like
[Credit: Travis R. Tischler]

Fossilised pterosaur bones were found by grazier Bob Elliot on Belmont Station outside the tiny town in 2017, the first find of a pterosaur from the Winton Formation. A two-week dig at the site uncovered the most complete specimen of its kind in Australia.


The well-preserved find includes five partial vertebrae, eight limb bones, a large part of the jaw and skull, and 40 full and partial teeth of a previously unknown pterosaur species, with the findings published in Scientific Reports.


Lead author and Swinburne University of Technology PhD candidate Adele Pentland said it was incredible to be part of the discovery.


«We didn’t really know what we were in for and we just kept on finding more material and it felt great,» she said. «Pterosaurs are quite rare in the fossil record because their bones are hollow and the outer bone is normally only about a millimetre thick.»











New pterosaur discovered in Australia's outback Queensland
Reconstruction showing which parts of the skeleton the pterosaur fossils came from
[Credit: Australian Age of Dinosaurs Museum]

Previously there were only 15 known fragmentary specimens of pterosaurs in Australia’s fossil record, which makes it exciting to see this new pterosaur described, said palaeontologist Steven Salisbury of the University of Queensland, who was not involved in the study.


«Every new little bit makes a big difference to understanding their evolutionary relationships and significance,» Dr Salisbury said.


Another reason pterosaur fossils are so rare is because scientists suspect they were soaring animals, so they would have spent a lot of their time over the ocean.


«Probably a lot of the time they died on the wing,» Dr Salisbury said. «And then for their carcasses to get preserved as fossils they would have to survive and get to the bottom of the ocean. There’s plenty of things in the ocean that would love to munch on a pterosaur.»











New pterosaur discovered in Australia's outback Queensland
A volunteer working on part of the Ferrodraco lentoni fossil
[Credit: Australian Age of Dinosaurs Museum]

In Australia, the smaller pterosaur fossils would have to survive in amongst all the dinosaur bones and other fossils.


«Pterosaurs aren’t always obvious, but you know slowly as more and more people are looking, things like this are emerging which is good,» Dr Salisbury said.


The researchers has dubbed the new species Ferrodraco lentoni, or Lenton’s Iron Dragon. It’s been nicknamed «Butch» for short, in honour of former Winton mayor Graham «Butch» Lenton.


Butch looks quite similar to some of the pterosaurs found in England, Dr Salisbury said, which is what scientists have long suspected based on previous pterosaur fossil finds.











New pterosaur discovered in Australia's outback Queensland
The pterosaur’s small front teeth showed it was a new species
[Credit: Australian Age of Dinosaurs Museum]

Given their flight capabilities, researchers expect to see closely related pterosaur species found all over the world. But Butch’s unique teeth set it apart from other similar species found elsewhere, Ms Pentland said.


This pterosaur was found to have a smaller first-tooth pair and smaller teeth further back in the mouth, compared to previously discovered species. Researcher aren’t yet sure why it has smaller teeth than usual.


«It might have something to do with the type of fish that it fed on,» Ms Pentland said. «Hopefully with more material that we [might] find … we’ll have a better idea of the bigger picture.»


While some groups of pterosaurs persisted right up until the end of the Cretaceous period 65 million years ago, this group of pterosaurs was thought to have died out 94 million years ago. But this find, in the slightly younger Winton Formation, suggests they might have survived later in Australia than elsewhere, perhaps as late as 90 million years ago.











New pterosaur discovered in Australia's outback Queensland
The discovery was the first find of pterosaur fossils in the area
[Credit: Australian Age of Dinosaurs Museum]

But Dr Salisbury warns we have to remember we don’t have a very substantial pterosaur fossil record to speculate on here. «It’s very much piecing together little pieces of a probably much larger puzzle,» he said. «You have to be careful how you read it, because it’s very likely that a lot of these groups of pterosaurs persisted longer, but we just don’t have the fossil record to show for it. For instance in Australia, anything younger than this part of the Winton Formation, so from about 92 million years ago until the end of the age of dinosaurs we’ve got virtually nothing in terms of any potential fossil record.»


The Winton region is a treasure trove of prehistoric fossils and world-renowned dinosaur trackways. But Australian Age of Dinosaurs Museum executive chairman David Elliot said it was still a huge find.


«We hold digs every year but it’s not often that we get something different, that’s so different and so exciting,» he said. «What makes it really exciting now is we’re just starting to get a whole ecosystem of dinosaurs together.»


Mr Elliot said there’s been a lot of work to get the find to this stage. «We’re so lucky to have Adele,» he said. «I think it’s got to be the coolest PhD project that’s ever been done in Australia and she’s done an amazing job of it.»


Authors: Damien Larkins & Suzannah Lyons | Source: ABC News Website [October 04, 2019]



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2019 October 1 Black Hole Safety Video Video Credit:…


2019 October 1


Black Hole Safety Video
Video Credit: NASA’s GSFC, SVS; Music: Prim and Proper from Universal Production Music


Explanation: If you were a small one-eyed monster, would you want to visit a black hole? Well the one in this video does – but should it? No, actually, but since our little friend is insistent on going, the video informs it what black holes really are, and how to be as safe as possible when visiting. Black holes are clumps of matter so dense that light cannot escape. Pairs of black holes, each several times the mass of our Sun, have recently been found to merge by detection of unusual gravitational radiation. The regions surrounding supermassive black holes in the centers of galaxies can light up as stars that near them get shredded. The closest known black hole to the Earth is V616 Mon, which is about 3,300 light years away. The best way for our monster friend to stay safe, the video informs, is to not go too close.


∞ Source: apod.nasa.gov/apod/ap191001.html


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Crowd Surfing Our cells are crammed with life – jostling…


Crowd Surfing


Our cells are crammed with life – jostling crowds of macromolecules, like these proteins and lipids vying for space in a computer model of a bacterial cell. With each having a purpose and a place to be, the situation looks chaotic, but new experiments suggest crowding actually helps certain particles travel faster. Researchers piped molecules of different sizes and textures into a microfluidic device designed to mimic real-life microscopic crowds. They discovered that squishy ones, more closely resembling particles in found living cells, squeeze between ‘crowder’ molecules, moving from crowded areas to where there’s space. Such concentration gradients are essential to help traffic into and out from cells, and now it seems inside them too. The next step is to find ways to control crowds inside cells, revealing new ways to guide the flow of macromolecules in health and disease.


Written by John Ankers



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Scientists Observe Year-long Plateaus in Decline of Type Ia Supernova Light Curves



Hubble Space Telescope color composite of SN2013dy within its host galaxy.


Credit: HST, Adam Riess, Or Graur





Hubble Space Telescope color composite of SN2018gv within its host galaxy.


Credit: HST, Adam Riess, Or Graur



Cambridge, MA — Scientists at the Center for Astrophysics | Harvard & Smithsonian have announced the discovery that, contrary to previously accepted knowledge, Type Ia supernovae experience light curve decline plateaus, and lengthy ones at that, lasting up to a year.


CfA scientist Or Graur first noticed strange light curve behaviors while studying late-time Type Ia supernovae in 2015, and this year confirmed light curve plateaus in Type Ia supernovae. «Most supernova research is conducted in the weeks or months immediately following an explosion, but we wanted to see how light curves behave at late times, around 500 to 1000 days after explosion,» said Graur. «Optical observations of SN2012gc in 2015 revealed a slowdown in the light curve as expected, but as we studied additional supernovae over time, it became apparent that other mechanisms were at play, so we started looking for patterns to explain what was going on.»


To better understand the strange behavior, Graur teamed up with Adam Riess of The Johns Hopkins University and the Space Telescope Science Institute, and 2011 winner of the Nobel Prize in Physics, to study nearby supernovae using Riess’s already-set HST programs. «Even though these were all nearby supernovae, at these late times they were very faint. We needed Hubble’s resolving power to be able to tell them apart from other stars in their respective galaxies,» said Graur. «But what made the difference to our observations was that Adam’s programs on Hubble also had near-infrared data in the H-band. What started as a fishing expedition revealed a portion of time where the light curve is flat, and that period lasts for up to a year. That was a surprise. I didn’t expect to see that.»


The idea of supernova light curve plateaus is not new to cosmology. Type IIP supernovae, which are born of the collapse and explosion of hydrogen-rich red super giants, commonly experience light curve plateaus roughly 100 days in length. Until the discovery of the Type Ia supernova light curve plateau, 100 days was considered a long-period plateau. Type Ia supernova light curve plateaus begin at between 150 and 500 days after explosion, and last approximately 350 days, or nearly a year.


«Up until this moment, the only plateaus seen in any type of supernova were in Type IIP, and they were relatively short compared to what we’re seeing in our observations. This is only the second time we’ve ever seen a plateau like this in a supernova,» said Graur. «What we’re seeing is in stark contrast to what we’ve always believed about Type Ia supernovae and it’s going to impact the way we apply Type Ia light curves to cosmological models in the future.»


The results of the study are published in Nature Astronomy. In addition to Graur—who also serves as a Research Associate at the American Museum of Natural History—and Riess, the study involved CfA scientist Arturo Avelino along with scientists Kate Maguire, Trinity College Dublin; Russell Ryan, Space Telescope Science Institute; Matt Nicholl, University of Edinburgh; Luke Shingles, Queens University Belfast; Ivo R. Seitenzahl, University of New South Wales Canberra; and, Robert Fisher, University of Massachusetts Dartmouth.

About Center for Astrophysics | Harvard & Smithsonian


Headquartered in Cambridge, Mass., the Center for Astrophysics | Harvard & Smithsonian (CfA) is a collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

For more information, contact:


Amy Oliver, Public Affairs
Fred Lawrence Whipple Observatory
Center for Astrophysics | Harvard & Smithsonian
+1 520-879-4406
amy.oliver@cfa.harvard.edu





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Fossil fish gives new insights into the evolution

An international research team led by Giuseppe Marrama from the Institute of Paleontology at the University of Vienna discovered a new and well-preserved fossil stingray with an exceptional anatomy, which greatly differs from living species. The find provides new insights into the evolution of these animals and sheds light on the recovery of marine ecosystems after the mass extinction occurred 66 million years ago. The study was recently published in the journal Scientific Reports.











Fossil fish gives new insights into the evolution
One of the three fossils of Lessiniabatis aenigmatica (MNHN F.Bol.566) from the famous fossil site of Monte Bolca (Italy)
preserved as part and counterpart. The specimen is housed in the Museum National d’Histoire Naturelle of Paris
[Credit: Giuseppe]

Stingrays (Myliobatiformes) are a very diverse group of cartilaginous fishes which are known for their venomous and serrated tail stings, which they use against other predatory fish, and occasionally against humans. These rays have a rounded or wing-like pectoral disc and a long, whip-like tail that carries one or more serrated and venomous stings. The stingrays include the biggest rays of the world like the gigantic manta rays, which can reach a «wingspan» of up to seven meters and a weight of about three tons.
Fossil remains of stingrays are very common, especially their isolated teeth. Complete skeletons, however, exist only from a few extinct species coming from particular fossiliferous sites. Among these, Monte Bolca, in northeastern Italy, is one of the best known. So far, more than 230 species of fishes have been discovered that document a tropical marine coastal environment associated with coral reefs which dates back to about 50 million years ago in the period called Eocene.











Fossil fish gives new insights into the evolution
Two living stingrays: a) Taeniura lymma; b) Neotrygon sp. The specimens are in the collection
f the Institute of Paleontology of the University of Vienna [Credit: Giuseppe Marrama]

This new fossil stingray has a flattened body and a pectoral disc ovoid in shape. What is striking is the absence of sting and the extremely short tail, which is not long as in the other stingrays, and does not protrude posteriorly to the disc. This body plan is not known in any other fossil or living stingray. Since this animal is unique and peculiar, the researchers named the new stingray Lessiniabatis aenigmatica, which means «bizarre ray from Lessinia» (the Italian area where Bolca is located).
More than 70 percent of the organisms, such as dinosaurs, marine reptiles, several mammal groups, numerous birds, fish and invertebrates, disappeared during the fifth largest extinction event in the Earth’s history occurred about 66 million years ago at the end of the Cretaceous. In marine environments, the time after this event is characterized by the emergence and diversification of new species and entire groups of bony and cartilaginous fishes (sharks and rays), which reoccupied the ecological niches left vacant by the extinction’s victims. The new species experimented sometimes new body plans and new ecological strategies.


«From this perspective, the emergence of a new body plan in a 50-million-year-old stingray such as Lessiniabatis aenigmatica is particularly intriguing when viewed in the context of simultaneous, extensive diversification and emergence of new anatomical features within several fish groups, during the recovery of the life after the end-Cretaceous extinction event,» states Giuseppe Marrama.


Source: University of Vienna [October 02, 2019]



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African evidence support Younger Dryas Impact Hypothesis

A team of scientists from South Africa has discovered evidence partially supporting a hypothesis that Earth was struck by a meteorite or asteroid 12 800 years ago, leading to global consequences including climate change, and contributing to the extinction of many species of large animals at the time of an episode called the Younger Dryas.











African evidence support Younger Dryas Impact Hypothesis
A world map that shows where similary platinum spikes have been discovered in the world. The latest discovery is at the
Wonderkrater site in Limpopo Province, South Africa [Credit: Francis Thackeray/Wits University]

The team, led by Professor Francis Thackeray of the Evolutionary Studies Institute at the University of the Witwatersrand in Johannesburg, South Africa, discovered evidence of a remarkable «platinum spike» at a site called Wonderkrater in the Limpopo Province, north of Pretoria in South Africa. Working with researcher Philip Pieterse from the University of Johannesburg and Professor Louis Scott of the University of the Free State, Thackeray discovered this evidence from a core drilled in a peat deposit, notably in a sample about 12 800 years old. This research was published in Palaeontologia Africana.


Noting that meteorites are rich in platinum, Thackeray said «Our finding at least partially supports the highly controversial Younger Dryas Impact Hypothesis (YDIH). We seriously need to explore the view that an asteroid impact somewhere on earth may have caused climate change on a global scale, and contributed to some extent to the process of extinctions of large animals at the end of the Pleistocene, after the last ice age.»


Many mammals became extinct in North America, South America and Europe at the time of the Younger Dryas. In South Africa a few extraordinary large animal species became extinct, not necessarily at exactly 12 800 years ago, but close to that period. These megafauna include a giant African buffalo, a large zebra, and a very big wildebeest.


Human populations may also have been indirectly affected at the time in question. In North America there is a dramatic termination of the stone tool technology of Clovis people. Remarkably, archaeologists in South Africa have detected an almost simultaneous termination of the Robberg stone artefact industry associated with people in some parts of the country, including the area around Boomplaas near the Cango Caves in the southern Cape, close to the town of Oudshoorn.


«Without necessarily arguing for a single causal factor on a global scale, we cautiously hint at the possibility that these technological changes, in North America and on the African subcontinent at about the same time, might have been associated indirectly with an asteroid impact with major global consequences,» says Thackeray. «We cannot be certain, but a cosmic impact could have affected humans as a result of local changes in environment and the availability of food resources, associated with sudden climate change.»


At Wonderkrater, the team has evidence from pollen to show that about 12 800 years ago there was temporary cooling, associated with the «Younger Dryas» drop in temperature that is well documented in the northern hemisphere, and now also in South Africa. According to some scientists, this cooling in widespread areas could at least potentially have been associated with the global dispersal of platinum-rich atmospheric dust.


A large crater 31 kilometres in diameter has been discovered in northern Greenland beneath the Hiawatha Glacier. «There is some evidence to support the view that it might possibly have been the very place where a large meteorite struck the planet earth 12 800 years ago,» says Thackeray. «If this was indeed the case, there must have been global consequences.»


Thackeray’s team believes their discovery of a platinum spike at about 12 800 years ago at Wonderkrater is just part of the strengthening view that an asteroid or cometary impact might have occurred at that time.


This is the first evidence in Africa for a platinum spike preceding climate change. Younger Dryas spikes in platinum have also been found in Greenland, Eurasia, North America, Mexico and recently also at Pilauco in Chile. Wonderkrater is the 30th site in the world for such evidence.


«Our evidence is entirely consistent with the Younger Dryas Impact Hypothesis» says Thackeray.


The discovery in South Africa is expected to be integrated with those made in other parts of the world, recognising that the source of the platinum at Wonderkrater could hypothetically be cosmic dust that was dispersed in the atmosphere after a meteorite impact in Greenland.


The probability of a large asteroid striking Earth in the future may seem to be low, but there are thousands of large rocks distributed primarily between Jupiter and Mars. One in particular, classified as Apophis 99942, is referred to as a «Potentially Hazardous Asteroid». It is 340 meters wide and will come exceptionally close to the Earth in 10 years’ time.


«The closest encounter will take place precisely on Friday April 13, 2029,» says Thackeray. «The probability of the Apophis 99942 asteroid hitting us then is only one in 100 000, but the probability of an impact may be even higher at some time in the future, as it comes close to Earth every 10 years.»


Source: University of the Witwatersrand [October 02, 2019]



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L-chondrite breakup might have contributed to Ordovician biodiversification

About 466 Mya, a major impact event took place between the orbits of Mars and Jupiter. Space dust spread all across the Solar System, and some of it was found near Saint-Petersburg, Russia, and in the south of Sweden.











L-chondrite breakup might have contributed to Ordovician biodiversification
The lower part of the Hallekis section with plots of bulk-rock concentrations of equilibrated ordinary chondritic
chromite (EC) grains, 3He and Al2O3, and 187Os/188Os ratios [Credit: Kazan Federal University]

«The enrichment of stratosphere by space dust in the mid-Ordovician might have triggered the ensuing cooling and biological diversification, and, consequently, late Ordovician glaciation. This only pertains to the Ordovician glaciation, not the Permian-Triassic and the contemporary one,» says co-author Andrei Dronov, Chief Research Associate at Kazan Federal University.


Initially, the researchers were interested not in the extinction itself but the preceding Ordovician radiation. That was a significant increase in the diversity of marine invertebrates which occurred about 20 to 30 million years before the extinction.


This is not the only catastrophic event to be a focus of attention for Kazan University. Stratigraphy of Oil and Gas Reservoirs Lab is studying the great Permian extinction under the guidance of Professor Vladimir Davydov (Boise State University).


«Even great extinctions do not happen across the whole planet simultaneously. Biodiversification can happen at the same time with the great extinction. Extinctions are triggered by a number of reasons, and it’s tough to determine which one is the primary. In this paper, the authors point out that catastrophes can be caused by seemingly very distant events. One can say this is also true for a person’s destiny and not just the history of Earth,» comments Senior Research Associate of the Stratigraphy Lab Vladimir Silantyev.


However paradoxical that may sound, it may be that the faunal diversification happened during the glaciation. Cosmic dust seems to have been a major contributor to that.


Authors: Adelya Shemelova, Yury Nurmeev | Source: Kazan Federal University [October 03, 2019]



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Dust in ice cores leads to new knowledge on the advancement of the ice before the ice age

Researchers from the section Physics of Ice, Climate and Earth (PICE) at the Niels Bohr Institute, University of Copenhagen, have succeeded in making a method to enlighten an otherwise dark period in climate history. Working with the ice core ReCap, drilled close to the coast in East Greenland, postdoc Marius Simonsen wondered why the dust particles from the interglacial period—the warmer period of time between the ice ages—were several times bigger than the dust particles from the ice age. His research led to the invention of a method able to map the advancement of the glaciers in cold periods and the melting in warmer periods. This data is important for the climate models we use to predict sea level rise. The result is now published in Nature Communications.











Dust in ice cores leads to new knowledge on the advancement of the ice before the ice age
Credit: Hubertus Fischer/Alfred Wegener Institute

The larger particles of dust don’t travel far—they come from East Greenland


Based on the hypothesis that the bigger dust particles in the ice couldn’t have come from afar, the then Ph.D. student, Marius Simonsen, examined the dust at select locations on the coast of East Greenland close to the drill site. The chemical composition turned out to be similar to the larger particles in the ice. The smaller particles of dust caught in the ice, on the other hand, travel from Asia, blown to Greenland by dust storms.


In other words, the bigger particles of dust in the ice must mean presence of bare land close to the drill site. The ice is composed of annual layers, like the growth rings in a tree, so the distribution of large and small dust particles can be linked to the advancement and melting of the ice. Large particles mean bare land in the vicinity, small particles mean the land is covered in ice. The end of the ice age, where the ice cap is receding, is well explained scientifically, Marius Simonsen explains. «But it is very difficult to retrieve data on the period before the ice age. The ice is an extremely strong natural force, so it grinds away everything when advancing. But with the new method, we have data on the advancement of the ice. All of a sudden, we have a link to information on how quickly we enter an ice age, in a way we never used to have.»


Gaining knowledge on Glacier reaction to atmospheric content of CO2 is crucial


It is important to know more about how glaciers react to changes in the atmosphere, and rather a lot is known on the composition of the atmosphere during the ice age. The results from the new method can now be used to compare the reaction in the masses of ice to changes in the atmospheric content of greenhouse gases like CO2.


Marius Simonsen says: «The glaciers receded at the beginning of the present interglacial, just like they do today because of climate change. The two scenarios are not entirely comparable, because there was much more inland ice then than now by the coast in East Greenland where the ice core is drilled. Never the less, the results are very interesting indeed when making climate models, because the models must be tested by comparison to reality. And in the new method we’ve acquired an anchor point in a period about which not much scientific knowledge existed.» The method helps putting constraints on our knowledge on the influence of greenhouse gases on ice melting and, consequently, sea level.


The method can provide us with new information on how fast the glaciers recede


Helle Astrid Kjær, Assistant professor in PICE, says the objective of PICE now is to utilize the new method at other locations so we can gather more data on the changes of glaciers in the past. The researchers are already planning new drill sites in North East Greenland and Canada. It is very likely that advancement and melting of the ice there is different from East Greenland. «Perhaps, with the new method, we are able to see how fast the ice age came in from the north and moved south,» Helle Astrid Kjær says.


It is a precondition for the feasibility of the method that bare land exists in the vicinity of the drill site, so dust particles can be found. This was the case during the last interglacial as the temperature then, app. 115,000 years ago, was up to 8 degrees C. warmer than today, according to a former study from the Niels Bohr Institute. Hence, the method will most likely be usable in North East Greenland and Canada. The researchers at the Niels Bohr Institute are already establishing new collaborations with Canadian researchers based on the new method.


Drilling of the ice core ReCap was supported by The Danish National Research Foundation, the American National Science Foundation, the German Alfred Wegener Institute and the European Union Horizon 2020 Research and Innovation Programme. The measurements of dust were supported by the EU funding ice2ice and Horizon 2020—TIPES.


Source: Niels Bohr Institute [October 03, 2019]



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Golden ratio observed in human skulls

The Golden Ratio, described by Leonardo da Vinci and Luca Pacioli as the Divine Proportion, is an infinite number often found in nature, art and mathematics. It’s a pattern in pinecones, seashells, galaxies and hurricanes.











Golden ratio observed in human skulls
Representation of the Golden Ratio 
[Credit: Getty Images]

In a new study investigating whether skull shape follows the Golden Ratio (1.618 … ), Johns Hopkins researchers compared 100 human skulls to 70 skulls from six other animals, and found that the human skull dimensions followed the Golden Ratio. The skulls of less related species such as dogs, two kinds of monkeys, rabbits, lions and tigers, however, diverged from this ratio.
«The other mammals we surveyed actually have unique ratios that approach the Golden Ratio with increased species sophistication,» says Rafael Tamargo, M.D., professor of neurosurgery at the Johns Hopkins University School of Medicine. «We believe that this finding may have important anthropological and evolutionary implications.»











Golden ratio observed in human skulls
Leonardo’s Vitruvian Man with Golden ratios highlighted
[Credit: Modified by Rafael Tamargo]

The Golden Ratio can be calculated by taking a line and dividing it into two unequal parts, with the length of the longer part divided by the shorter length being equal to the entire length divided by the longer part. Tamargo’s interest in history and anatomy led him in 2010 to publish on finding a human brain and spinal cord in the depiction of God in Michelangelo’s Sistine Chapel painting.


Jonathan Pindrik, now a pediatric neurosurgeon at Nationwide Children’s Hospital in Ohio, also contributed to the study.


The researchers published their findings in the September issue of The Journal of Craniofacial Surgery.


Source: Johns Hopkins Medicine [October 03, 2019]



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Were hot, humid summers the key to life’s origins?

Uncovering how the first biological molecules (like proteins and DNA) arose is a major goal for researchers attempting to solve the origin of life. Today, chemists at Saint Louis University, in collaboration with scientists at the College of Charleston and the NSF/NASA Center for Chemical Evolution, published a study in the journal Nature Communications that suggests deliquescent minerals—which dissolve in water they absorb from humid air—can assist the construction of proteins from simpler building blocks during cycles timed to mimic day and night on the early Earth.











Were hot, humid summers the key to life's origins?
A new study from the NSF-NASA Center for Chemical Evolution reports a possible model for how biological polymers
may have formed during the origin of life on Earth [Credit: Bracher Lab, Saint Louis University]

«In terms of the history of the planet, how life originated is probably the greatest scientific question we can ask,» said Paul Bracher, Ph.D., assistant professor of chemistry at Saint Louis University and principal investigator of the study. «A key piece of this grand challenge is figuring out how big polymer molecules we know to be important for life could have formed before all of our biological machinery evolved to make them.»


Baking Proteins in the Prebiotic Kitchen


Amino acids are the molecular building blocks linked together by peptide bonds to form proteins. Chemists have long known that simply baking mixtures of amino acids to dryness will lead to the formation of peptide bonds. The yields of peptides improve when water is added and the sample is dried again, after the ingredients are allowed to re-mix. Subjecting amino acids to repeated wet-dry cycles could have been a good recipe for cooking up peptides and proteins on the early Earth, as hot sunny days interrupted by the occasional rainstorm seem like reasonable weather patterns. But a major criticism of this process is its reliance on unpredictable storms that may have watered-down the ingredients to excess.


Water: A Necessary But Problematic Ingredient


«Follow the water» has been NASA’s motto in the search for life outside our planet. Without water, the biochemistry of life as-we-know-it would be impossible.


In origin-of-life chemistry, the solution is often the problem. For constructive chemical processes to occur, the building blocks must dissolve in a liquid solution to find partners to react. On Earth, this medium is water, the solvent of life.


However, water can be a double-edged sword. While life needs water to survive, too much water can be destructive. Most biological molecules are prone to hydrolysis, a process in which water breaks apart chemical bonds. And too much water will eventually flood developing cells that contain the evolving biomolecules, strewing them too far away from each other to react.


A Pinch of Salt


Deliquescent minerals offer a means to side-step the limitations of traditional wet-dry cycling. These salts absorb a limited amount of water from the air, based on the relative humidity, offering natural regulation of the water present in a solution.


The new study—a collaboration between scientists at SLU and the College of Charleston—reports how deliquescent salts can assist making peptides from the simplest amino acid, glycine, during self-regulated, repeating wet-dry cycling. During the day, the reaction mixtures form peptides when they evaporate to dryness at high temperatures. At night, the reactions acquire water from the atmosphere to form aqueous solutions at low temperatures, thereby rewetting without the addition of water by a rainstorm and avoiding the possibility of destructive overdilution.


Seemingly minor differences, like changing the ambient humidity from 50% to 70%, can lead to profound differences in the tendency of samples to absorb water, and hence, large differences in the yields of reactions they host. And while potassium and sodium are neighbors on the periodic table with almost identical reactivities, many potassium salts are deliquescent where their sodium counterparts are not. The salt K2HPO4 fostered yields of peptides from glycine ten times greater than in Na2HPO4.


The team believes their system may provide clues relevant to solving the mystery of why all life on Earth spends so much energy enriching potassium inside cells and throwing sodium out.


«This creative research, exploring how the chemical environment regulates formation of large molecules, represents another major step toward CCE’s goal of understanding the chemistries behind early biological molecules. Successful engagement of undergraduate researchers in this work also reflects NSF’s mission of integration of research with education for the training of future workforce,» said Dr. Lin He, the Acting Deputy Division Director for the Division of Chemistry at the National Science Foundation.


Bakeries Beyond Earth


Despite their exotic-sounding name, deliquescent salts are common and exist in natural settings where they can play a role in enabling liquid water to exist in environments that are otherwise too cold and/or dry.


In a hyper-arid region of Chile’s Atacama Desert that is inhospitable to life, microbial communities reside in deposits of the mineral halite. Their photosynthetic activity spikes when the relative humidity rises above 70%, exceeding the threshold where their halite environment becomes deliquescent.


Deliquescent mixtures of chloride and perchlorate salts have also been identified on Mars. These mixtures appear to flow seasonally and have garnered significant interest from astrobiologists as the only liquid water on the surface of the planet.


Making use of these naturally occurring minerals, this new study proposes wet-dry cycles regulated by natural daily oscillations in temperature and humidity—not on uncontrollable rain events—constitute a prebiotically feasible model for driving the chemical formation of biopolymers central to biology.


Was a simple pinch of salt the missing ingredient for cooking up life on Earth? We may never know for sure, but in this case, it certainly seems to make a great improvement to the recipe for baking proteins.


Source: Saint Louis University [October 04, 2019]



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