понедельник, 28 января 2019 г.

Stair Hole | #Geology #GeologyPage #England Stair Hole is a…

Stair Hole | #Geology #GeologyPage #England

Stair Hole is a small cove that is to the west of Lulworth Cove in Dorset, southern England.

The folded limestone strata known as the Lulworth crumple are particularly visible at Stair Hole.

Read more & More Photos: http://www.geologypage.com/2017/01/stair-hole.html

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Calcite | #Geology #GeologyPage #Mineral Locality: Dal’negorsk,…

Calcite | #Geology #GeologyPage #Mineral

Locality: Dal’negorsk, Primorskiy Kray, Far-Eastern Region, Russia

Size: 4.5 x 3.6 x 2.6

Photo Copyright © Saphira Minerals

Geology Page



Fluorite | #Geology #GeologyPage #Mineral Locality: Okorusu…

Fluorite | #Geology #GeologyPage #Mineral

Locality: Okorusu mine, Otjiwarongo District, Namibia

Size: 5.6 x 5.0 x 2.0 cm

Photo Copyright © Spirifer Minerals

Geology Page



Opal | #Geology #GeologyPage #Mineral #Opal Locality: Coober…

Opal | #Geology #GeologyPage #Mineral #Opal

Locality: Coober Pedy, Central North, South Australia, Australia

Overall Measurements: 3.00 x 1.97 x 2.30 inches

Photo Copyright © Heritage Auctions

Geology Page



Stone columns of Crowley Lake | #Geology #GeologyPage…

Stone columns of Crowley Lake | #Geology #GeologyPage #California

Crowley Lake is a reservoir on the upper Owens River in southern Mono County, California, in the United States. Crowley Lake is 15 miles south of Mammoth Lakes.

Geology Page



‘Twelve Apostles’ Stone Circle, Hollywood Station, Dumfries, Scotland,...

‘Twelve Apostles’ Stone Circle, Hollywood Station, Dumfries, Scotland, 27.1.19.

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2018 January 28 The Long Gas Tail of Spiral Galaxy D100 Image…

2018 January 28

The Long Gas Tail of Spiral Galaxy D100
Image Credit & Copyright: NASA, ESA, Hubble, Subaru Telescope, W. Cramer (Yale) et al., M. Yagi, J. DePasquale

Explanation: Why is there long red streak attached to this galaxy? The streak is made mostly of glowing hydrogen that has been systematically stripped away as the galaxy moved through the ambient hot gas in a cluster of galaxies. Specifically, the galaxy is spiral galaxy D100, and cluster is the Coma Cluster of galaxies. The red path connects to the center of D100 because the outer gas, gravitationally held less strongly, has already been stripped away by ram pressure. The extended gas tail is about 200,000 light-years long, contains about 400,000 times the mass of our Sun, and stars are forming within it. Galaxy D99, visible to D100’s lower left, appears red because it glows primarily from the light of old red stars – young blue stars can no longer form because D99 has been stripped of its star-forming gas. The featured false-color picture is a digitally enhanced composite of images from Earth-orbiting Hubble and the ground-based Subaru telescope. Studying remarkable systems like this bolsters our understanding of how galaxies evolve in clusters.

∞ Source: apod.nasa.gov/apod/ap190128.html

Debunking the solar-cycle/North Atlantic winter weather connection

The North Atlantic Oscillation (NAO) is considered a key driver of winter weather patterns over the northern hemisphere. A positive NAO is linked with more windstorms, and mild and wet winters in Europe. A negative NAO indicates snowy and cold winters in Europe. In recent years, published research has claimed the existence of a correlation between the NAO and the 11-year solar cycle, a periodic change in the sun’s activity. That theory has held that the connection between the NAO and the solar cycle is strong enough to inform predictions of the NAO as much as a decade in advance, which would in turn, enable scientists to predict winter weather patterns as many as ten years in advance.

Debunking the solar-cycle/North Atlantic winter weather connection
Cyclic variations in the energy emitted by the sun have been thought to affect weather patterns in the North Atlantic and
the likelihood of storms and floods over Europe. These influences by the sun are insignificant, and could have been
due to chance, suggests a new study of the instrumental record and new chemistry-climate model simulations
 led by Columbia/LDEO scientists [Credit: Shutterstock and NASA’s Earth Observatory]

However, in a research paper published in Nature Geoscience, Gabriel Chiodo, Jessica Oehrlein and Lorenzo Polvani, scientists at Lamont-Doherty Earth Observatory and the School of Engineering at Columbia University and other colleagues present evidence that there is no definite connection between the solar cycle and the NAO.

The research essentially debunks what was considered a “demonstrated link” between the 11-year sun cycle and winter weather over the northern hemisphere and found it is actually, for the most part, a coincidental alignment. With the use of sophisticated computer modeling and extended observations, the new research shows that before 1960 evidence of any correlation simply vanishes.

“What we’re saying is, the theory was basically a mirage,” said Polvani.

“We had a hunch that some of the theories out in the literature were not really robust, so we revisited using four more sophisticated reconstructions of different data farther back in time than what people have done so far, and used reconstructions that go back to the 19th Century, and we see that these correlations go away. These apparent comings and goings of correlation are really due to atmospheric variability, and not the sun” said Chiodo.

The implications of the findings are substantial for Europe and for science. The correlation theory, if proven, would have meant great advantages to societies in the northern hemisphere, giving enough warning of periods of intense storms and flooding to inform community planning efforts. This latest research, debunking the correlation, will be important for climate research into the future, as it implies that the causes for decadal weather changes over Europe lies elsewhere, not in the solar variations.

Both Polvani and Chiodo say they expect the researchers that led the work postulating a link between the NAO and the sun cycle, will be eager to challenge these findings. “It’s quite simple. There is a very interesting sociological bias in the way climate science is done. Colleagues are easily convinced that climate variations are somehow coming from outside. So, there’s great resistance to accepting the fact that – sometimes – the climate is varying just because the climate varies on its own, period.” said Polvani. “I hope they do push back,” said Chiodo. “That’s the way science is done.”

Author: Marie Denoia Aronsohn | Source: Columbia University [January 23, 2019]



When coral species vanish, their absence can imperil surviving corals

Waves of annihilation have beaten coral reefs down to a fraction of what they were 40 years ago, and what’s left may be facing creeping death: The effective extinction of many coral species may be weakening reef systems thus siphoning life out of the corals that remain.

When coral species vanish, their absence can imperil surviving corals
A wave of death sweeps over an experimental plot of corals made up of a single species. Plots of corals containing
 three species faired much better. Biodiversity appears to measurably make a difference in overall coral health
[Credit: Georgia Tech/Cody Clements]

In the shallows off Fiji’s Pacific shores, two marine researchers from the Georgia Institute of Technology for a new study assembled groups of corals that were all of the same species, i.e. groups without species diversity. When Cody Clements snorkeled down for the first time to check on them, his eyes instantly told him what his data would later reveal.

“One of the species had entire plots that got wiped out, and they were overgrown with algae,” Clements said. “Rows of corals had tissue that was brown – that was dead tissue. Other tissue had turned white and was in the process of dying.”

36 ghastly plots

Clements, a postdoctoral researcher and the study’s first author, also assembled groups of corals with a mixture of species, i.e. biodiverse groups, for comparison. In total, there were 36 single-species plots, or monocultures. Twelve additional plots contained polycultures that mixed three species.

By the end of the 16-month experiment, monocultures had faired obviously worse. And the study had shown via the measurably healthier growth in polycultures that science can begin to quantify biodiversity’s contribution to coral survival as well as the effects of biodiversity’s disappearance.

“This was a starter experiment to see if we would get an initial result, and we did,” said principal investigator Mary Hay, a Regents Professor and Harry and Linda Teasley Chair in Georgia Tech’s School of Biological Sciences. “So much reef death over the years has reduced coral species variety and made reefs more homogenous, but science still doesn’t understand enough about how coral biodiversity helps reefs survive. We want to know more.”

The study’s insights could aid ecologists restocking crumbling reefs with corals — which are animals. Past replenishing efforts have often deployed patches of single species that have had trouble taking hold, and the researchers believe the study should encourage replanting using biodiverse patches.

40 years’ decimation

The decimation of corals Hay has witnessed in over four decades of undersea research underscores this study’s importance.

When coral species vanish, their absence can imperil surviving corals
The experimental patch with single-species plots and three-species plots in shallow
coral reefs off Fiji’s Pacific shores [Credit: Georgia Tech/Cody Clements]

“It’s shocking how quickly the Caribbean reefs crashed. In the 1970s and early 1980s, reefs consisted of about 60 percent live coral cover,” Hay said. “Coral cover declined dramatically through the 1990s and has remained low. It’s now at about 10 percent throughout the Caribbean.”

“You used to find living diverse reefs with structurally complex coral stands the size of city blocks. Now, most Caribbean reefs look more like parking lots with a few sparse corals scattered around.”

84 percent loss

The fact that the decimation in the Pacific is less grim is bitter irony. About half of living coral cover disappeared there between the early 1980s and early 2000s with declines accelerating since.

“From 1992 to 2010, the Great Barrier Reef, which is arguably the best-managed reef system on Earth, lost 84 percent,” Clements said. “All of this doesn’t include the latest bleaching events reported so widely in the media, and they killed huge swaths of reef in the Pacific.”

The 2016 bleaching event also sacked reefs off of Fiji where the researchers ran their experiment. The coral deaths have been associated with extended periods of ocean heating, which have become much more common in recent decades.

10 times more species

Still, there’s hope. Pacific reefs support ten times as many coral species as Caribbean reefs, and Clements’ and Hay’s new study suggests that this higher biodiversity may help make these reefs more robust than the Caribbean reefs. There, many species have joined the endangered list, or are “functionally extinct,” still present but in traces too small to have ecological impact.

When coral species vanish, their absence can imperil surviving corals
Seaweed has conquered this plot of single-species corals, which are dead or sickly and surrendering
their table to the competing microalgae [Credit: Georgia Tech/Cody Clements]

The Caribbean’s coral collapse may have been a warning shot on the dangers of species loss. Some coral species protect others from getting eaten or infected, for example.

“A handful of species may be critical for the survival of many others, and we don’t yet know well enough which are most critical. If key species disappear, the consequences could be enormous,” said Hay, who believes he may have already witnessed this in the Caribbean. “The decline of key species may drive the decline of others and potentially create a death spiral.”

864 abrasive animals

Off Fiji’s shores, Clements transported by kayak, one by one, 48 concrete tables he had built on land. He dove them into place and mounted on top of them 864 jaggy corals in planters he had fashioned from the tops of plastic soda bottles.

“I scratched a lot of skin off of my fingers screwing those corals onto the tables,” he said, laughing at the memory. “I drank enough saltwater through my snorkel doing it, too.”

Clements laid out 18 corals on each tabletop: Three groups of monocultures filled 36 tables (12 with species A, 12 with species B, 12 with species C). The remaining 12 tabletops held polycultures with balanced A-B-C mixtures. He collected data four months into the experiment and at 16 months.

The polycultures all looked great. Only one monoculture species, Acropora millepora, had nice growth at the 16-month mark, but that species is more susceptible to disease, bleaching, predators, and storms. It may have sprinted ahead in growth in the experiment, but long-term it would probably need the help of other species to cope with its own fragility.

“Corals and humans both may do well on their own in good times,” Hay said. “But when disaster strikes, friends may become essential.”

The results of the study appear in the journal Nature Ecology and Evolution.

Source: Georgia Institute of Technology [January 23, 2019]



Climate change tipping point could be coming sooner than we think

Global carbon emissions reached a record high in 2018, rising by an estimated 3.4 percent in the U.S. alone. This trend is making scientists, government officials, and industry leaders more anxious than ever about the future of our planet. As United Nations Secretary General António Guterres said at the opening of the 24th annual U.N. climate conference on December 3, “We are in deep trouble with climate change.”

Climate change tipping point could be coming sooner than we think
Limpopo province in South Africa– a semi-arid region shown to have reduced carbon uptake due to
soil moisture anomalies. This negative trend is expected to continue through the 21st century
[Credit: Julia K Green/Columbia Engineering]

A Columbia Engineering study, published this week in Nature, confirms the urgency to tackle climate change. While it’s known that extreme weather events can affect the year-to-year variability in carbon uptake, and some researchers have suggested that there may be longer-term effects, this new study is the first to actually quantify the effects through the 21st century and demonstrates that wetter-than-normal years do not compensate for losses in carbon uptake during dryer-than-normal years, caused by events such as droughts or heatwaves.

Anthropogenic emissions of CO2 — emissions caused by human activities — are increasing the concentration of CO2 in the Earth’s atmosphere and producing unnatural changes to the planet’s climate system. The effects of these emissions on global warming are only being partially abated by the land and ocean. Currently, the ocean and terrestrial biosphere (forests, savannas, etc.) are absorbing about 50% of these releases — explaining the bleaching of coral reefs and acidification of the ocean, as well as the increase of carbon storage in our forests.

“It is unclear, however, whether the land can continue to uptake anthropogenic emissions at the current rates,” says Pierre Gentine, associate professor of earth and environmental engineering and affiliated with the Earth Institute, who led the study. “Should the land reach a maximum carbon uptake rate, global warming could accelerate, with important consequences for people and the environment. This means that we all really need to act now to avoid greater consequences of climate change.”

Working with his PhD student Julia Green, Gentine wanted to understand how variability in the hydrological cycle (droughts and floods, and long-term drying trends) was affecting the capacity of the continents to trap some of the emissions of CO2. The research is particularly timely as climate scientists have predicted that extreme events will likely increase in frequency and intensity in the future, some of which we are already witnessing today, and that there will also be a change in rainfall patterns that will likely affect the ability of the Earth’s vegetation to uptake carbon.

To define the amount of carbon stored in vegetation and soil, Gentine and Green analyzed net biome productivity (NBP), defined by the Intergovernmental Panel on Climate Change as the net gain or loss of carbon from a region, equal to the net ecosystem production minus the carbon lost from disturbance like a forest fire or a forest harvest.

The researchers used data from four Earth System Models from the GLACE-CMIP5 (Global Land Atmosphere Coupling Experiment — Coupled Model Intercomparison Project) experiments, to run a series of experiments to isolate reductions in NBP that are due strictly to changes in soil moisture. They were able to isolate the effects of changes in long-term soil moisture trends (i.e. drying) as well as short-term variability (i.e., the effects of extreme events such as floods and droughts) on the ability of the land to uptake carbon.

“We saw that the value of NBP, in this instance a net gain of carbon on the land surface, would actually be almost twice as high if it weren’t for these changes (variability and trend) in soil moisture,” says Green, the paper’s lead author. “This is a big deal! If soil moisture continues to reduce NBP at the current rate, and the rate of carbon uptake by the land starts to decrease by the middle of this century — as we found in the models — we could potentially see a large increase in the concentration of atmospheric CO2 and a corresponding rise in the effects of global warming and climate change.”

Gentine and Green note that soil-moisture variability notably reduces the present land carbon sink, and their results show that both variability and drying trends reduce it in the future. By quantifying the critical importance of soil-water variability for the terrestrial carbon cycle, and the reduction in carbon uptake due to the effects of these changes in soil moisture, the study findings highlight the necessity of implementing improved modeling of vegetation response to water stress and land-atmosphere coupling in Earth system models to constrain the future terrestrial carbon flux and to better predict future climate.

“Essentially, if there were no droughts and heat waves, if there were not going to be any long-term drying over the next century, then the continents would be able to store almost twice as much carbon as they do now,” says Gentine. “Because soil moisture plays such a large role in the carbon cycle, in the ability of the land to uptake carbon, it’s essential that processes related to its representation in models become a top research priority.”

There is still a great deal of uncertainty on how plants respond to water stress, and so Green and Gentine will continue their work on improving representations of vegetation response to soil moisture changes. They are now focusing on the tropics, a region with lots of unknowns, and the largest terrestrial carbon sink, to determine how vegetation activity is being controlled by both changes in soil moisture as well as atmospheric dryness. These findings will provide guidance on improving the representation of plant water stress in the tropics.

“This study is highly valuable as it shines a bright spotlight on just how important water is for the uptake of carbon by the biosphere,” says Chris Schwalm, an associate scientist at Woods Hole Research Center and an expert in global environmental change, carbon cycle sensitivity and modeling frameworks who was not involved in the study. “It also exposes underdeveloped aspects of Earth system modeling such as processes related to vegetation water-stress and soil moisture, which can be targeted during model development for better predictive capacity in the context of global environmental change.”

Author: Holly Evarts | Source: Columbia University School of Engineering and Applied Science [January 23, 2019]



Large volcanic eruption in Scotland may have contributed to…

Large volcanic eruption in Scotland may have contributed to prehistoric global warming http://www.geologypage.com/2019/01/large-volcanic-eruption-in-scotland-may-have-contributed-to-prehistoric-global-warming.html

Fossilized slime of 100-million-year-old hagfish shakes up…

Fossilized slime of 100-million-year-old hagfish shakes up vertebrate family tree http://www.geologypage.com/2019/01/fossilized-slime-of-100-million-year-old-hagfish-shakes-up-vertebrate-family-tree.html

Ancient carpet shark discovered with ‘spaceship-shaped’ teeth…

Ancient carpet shark discovered with ‘spaceship-shaped’ teeth http://www.geologypage.com/2019/01/ancient-carpet-shark-discovered-with-spaceship-shaped-teeth.html

Fault lines are no barrier to safe storage of CO2 below ground…

Fault lines are no barrier to safe storage of CO2 below ground http://www.geologypage.com/2019/01/fault-lines-are-no-barrier-to-safe-storage-of-co2-below-ground.html

Stellar winds, the source material for the universe, are clumpy

Data recorded by NASA’s Chandra X-ray Observatory of a neutron star as it passed through a dense patch of stellar wind emanating from its massive companion star provide valuable insight about the structure and composition of stellar winds and about the environment of the neutron star itself. A paper describing the research, led by Penn State astronomers, appears in Monthly Notices of the Royal Astronomical Society.

Stellar winds, the source material for the universe, are clumpy
Illustration of a high-mass X-ray binary system made up of a compact, incredibly dense neutron star paired with a massive
‘normal’ supergiant star. New data from NASA’s Chandra X-ray Observatory shows that the neutron star in the high-mass
X-ray binary, OAO 1657-415, passed through a dense patch of stellar wind from its companion star,
demonstrating the clumpy nature of stellar winds [Credit: NASA/CXC/M.Weiss]

“Stellar winds are the fast-flowing material — composed of protons, electrons, and metal atoms — ejected from stars,” said Pragati Pradhan, a postdoctoral researcher in astronomy and astrophysics at Penn State and the lead author of the paper. “This material enriches the star’s surroundings with metals, kinetic energy, and ionizing radiation. It is the source material for star formation. Until the last decade, it was thought that stellar winds were homogenous, but these Chandra data provide direct evidence that stellar winds are populated with dense clumps.”
The neutron star observed is part of a high-mass X-ray binary system — the compact, incredibly dense neutron star paired with a massive ‘normal’ supergiant star. Neutron stars in binary systems produce X-rays when material from the companion star falls toward the neutron star and is accelerated to high velocities. As a result of this acceleration, X-rays are produced that can inturn interact with the materials of the stellar wind to produce secondary X-rays of signature energies at various distances from the neutron star. Neutral — uncharged — iron atoms, for example, produce fluorescence X-rays with energies of 6.4 kilo-electron volts (keV), roughly 3000 times the energy of visible light. Astronomers use spectrometers, like the instrument on Chandra, to capture these X-rays and separate them based on their energy to learn about the compositions of stars.

“Neutral iron atoms are a more common component of stars so we usually see a large peak at 6.4 keV in the data from our spectrometers when looking at X-rays from most neutron stars in a high-mass X-ray binary system,” said Pradhan. “When we looked at X-ray data from the high-mass X-ray binary system known as OAO 1657-415 we saw that this peak at 6.4 keV had an unusual feature. The peak had a broad extension down to 6.3 keV. This extension is referred to as a ‘Compton shoulder’ and indicates that the X-rays from neutral iron are being back scattered by dense matter surrounding the star. This is only the second high-mass X-ray binary system where such a feature has been detected.”

The researchers also used the Chandra’s state-of-the-art engineering to identify a lower limit on the distance from the neutron star that the X-rays from neutral iron are formed. Their spectral analysis showed that neutral iron is ionized at least 2.5 light-seconds, a distance of approximately 750 million meters or nearly 500,000 miles, from the neutron star to produce X-rays.

“In this work, we see a dimming of the X-rays from the neutron star and a prominent line from neutral iron in the X-ray spectrum — two signatures supporting the clumpy nature of stellar winds,” said Pradhan. “Furthermore, the detection of Compton shoulder has also allowed us to map the environment around this neutron star. We expect to be able to improve our understanding of these phenomenon with the upcoming launch of spacecrafts like Lynx and Athena, which will have improved X-ray spectral resolution.”

For Pradhan’s post-doctoral work at Penn State under the supervision of Professor of Astronomy and Astrophysics David Burrows, Associate Research Professor of Astronomy and Astrophysics Jamie Kennea, and Research Professor of Astronomy and Astrophysics Abe Falcone, she is majorly involved in writing algorithms for on-board detection of X-rays from transient astronomical events such as those seen from these high-mass X-ray binary systems for instruments that will be on the Athena spacecraft.

Pradhan and her team also have a follow-up campaign looking at the same high-mass X-ray binary with another NASA satellite — NuSTAR, which will cover a broader spectrum of X-rays from this source ranging in energies from ~ 3 to 70 keV — in May 2019.

“We are excited about the upcoming NuSTAR observation too,” said Pradhan. “Such observations in hard X-rays will add another dimension to our understanding of the physics of this system and we will have an opportunity to estimate the magnetic field of the neutron star in OAO 1657-415, which is likely a million times stronger than strongest magnetic field on Earth.”

Author: Sam Sholtis | Source: Penn State University [January 24, 2019]



Stars shrouded in iron dust

Stars with masses between one and eight times the mass of the Sun evolve along the asymptotic giant branch (AGB) before ending their lives as white dwarfs. It is during this rapid but crucial phase when the stars expand to huge dimensions and cool down, losing a major fraction of their mass due to the strong stellar winds. The low temperature and high density of the winds provide ideal conditions for the condensation of dust grains in their circumstellar envelopes.

Stars shrouded in iron dust
Infrared image of the Large Magellanic Cloud (LMC) as obtained with the Spitzer Space Telescope. Upper inset:
the comparison between the Spitzer/IRS spectrum (black solid line) of the star SSID 4486 and the best fit
theoretical spectrum of a 5 solar mass AGB star (red solid line) surrounded by ~70 percent of iron dust;
the green dashed line refers to the corresponding theoretical spectrum of the same model without iron
dust. Lower inset: artist’s impression of a giant AGB star ejecting matter to the interstellar medium
[Credit: LMC image: Aladin-software in Spitzer colors; Artistic image: JAXA]

The dust produced by the stars in their AGB phase and expelled into the interstellar medium is important for the lives of the galaxies, because this is an essential component for the formation of new stars, and also of planets. That is why characterising the type of dust (solid state organic components, or inorganic components) and the quantity of dust produced by these giant stars is very interesting to the astronomical community.
A study published this week in The Astrophysical Journal Letters has answers to the puzzles of a peculiar group of massive AGB stars situated in the Large Magellanic Cloud. Comparing the infrared observations made with the Spitzer Space Telescope (and predictions for the future James Webb Space Telescope) with the theoretical models developed by this group, they have discovered that these stars have masses around 5 solar masses, were formed around 100 million years ago, and are poor in metals (such as iron, magnesium and silicon).

Unexpectedly they have discovered that the infrared spectral energy distributions can be reproduced only if iron dust is the principal dust component of their circumstellar envelopes. This is uncommon around massive AGB stars. Before it was known that they mainly produced silicates, large quantities of dust rich in oxygen and silicon, as well as magnesium. But this finding is even more surprising if we consider the metal poor environment of the stars under study.

We have characterized for the first time this class of stars with unique spectral properties. The low metallicity of these giant stars is the essential ingredient which gives peculiar conditions permitting the formation of large quantities of iron dust” explains Ester Marini, the first author of the article and a doctoral student at the Roma Tre University. She adds “In fact, in metal poor environments the complex nucleosynthesis within massive AGB stars is so advanced that it burns up almost all the magnesium and oxygen, necessary to form other types of dust, such as the silicates”.

Under these particular conditions iron dust becomes the main component of the dust formed by these stars. “This result is an important confirmation of the theory of iron dust in metal poor environments, already hinted at in independent observational evidence” says the IAC researcher Aníbal García Hernández, a co-author of the work, and one of the initiators of the fruitful collaboration between the IAC and the Osservatorio Astronomico di Roma (OAR-INAF) on these type of giant AGB stars.

“The arrival of the James Webb Space Telescope (JWST) will open up new possibilities for investigating this case in depth”, comments Flavia Dell’Agli, a postdoctoral researcher at the IAC, and second author of the article. She adds “That future telescope will greatly enhance the number of resolved extragalactic AGB stars” and that the MIRI instrument on the JWST will be “ideal for identifying this class of stars in other galaxies of the Local Group”.

Source: Instituto de Astrofísica de Canarias [January 24, 2019]



Research reveals new species are evolving fastest in Antarctica

Biologists have long speculated that evolution is sped up by relatively high tropical temperatures, with development being slower in cooler and deeper waters. However, this research finds that evolution does not follow one course, but rather depends on the geological, climatic and biological history of each ecosystem. Evolution proceeded differently in shallow and deep seas.

Research reveals new species are evolving fastest in Antarctica
Ophiuroidea, brittle star. Collected and photographed during the Museums Victoria and partners
‘Sampling the Abyss’ voyage on the RV Investigator [Credit: Museums Victoria]

Speciation was found to be highest in the coldest region: Antarctica. These waters are still apparently recovering from extinction events of tens of millions of years ago, when ice sheets began to dominate and water temperatures plummeted. New species that evolved as a result are still in the process of diversifying, and are doing so rapidly.
By contrast, although diversity in tropical deep seas (deeper than 200 metres) is high, it is not an environment that is rapidly producing new species, but rather accumulated its rich biodiversity over millions of years. Tropical deep seas are a refuge for ancient fauna, or “living fossils,” mainly due to relatively stable conditions over time.

To study patterns of evolution across the world’s oceans, the team focused on the evolution of deep-sea ‘brittle stars’ (Ophiuroidea). These strange, spiny echinoderms with a typically circular body and five long, flexible arms, are abundant on the seafloor globally. Although they will be unfamiliar to many, their abundance makes them the perfect group for studying large-scale patterns of how marine life arose and spread around the planet.

Research reveals new species are evolving fastest in Antarctica
Map showing geographic distribution of samples [Credit: Museums Victoria]

The researchers utilised data collected on 2017’s pioneering “Sampling the Abyss’ voyage aboard CSIRO Marine National Facility research vessel Investigator, led by Museums Victoria. The month-long expedition explored the abyssal ocean depths off the eastern coast of Australia for the first time. Dr. O’Hara was Chief Scientist on the voyage, and this publication is the first major paper to be published as a result of the voyage.
DNA was used to reconstruct a comprehensive picture of how brittle stars have evolved across the Indian and Pacific Oceans in the southern hemisphere. Dr. O’Hara explained, “Museum collections are a treasure house of preserved biodiversity collected from thousands of scientific expeditions. Sequencing the DNA from these specimens can unlock the history of life on our planet. The digitisation and DNA sequencing of museum collections is providing a new way of looking at how life has evolved and spread around the globe.”

The deep sea is the world’s largest ecosystem, an ancient ark of relics from the dinosaur era, where “living fossils” exist at the same time that new species are fast evolving. These environments require as much protection as more famous and familiar habitats, like coral reefs and mangroves. Yet a lack of knowledge about marine life in these dark waters has made it unclear how best to protect and preserve these environments from human exploitation like fishing or deep-sea mining.

Research reveals new species are evolving fastest in Antarctica
Dr. Tim O’Hara in Marine Vertebrate research laboratory holding a specimen jar containing brittle stars
[Credit: Museums Victoria]

Dr. O’Hara and his team’s paper, published in Nature, is the result of what he hopes will be the first stage of a global project to shed further light on processes of evolution in precious deep sea environments, and how we can best project them.

Author: Anastasia Casagrande | Source: Museums Victoria [January 24, 2019]



An entire botanical garden of genomes

An article published in the Open-Access journal GigaScience provides data that effectively triples the number of plant species with available genome data. This mammoth amount of work comes on the back of the growing efforts of the scientific community to sequence more plant genomes to aid in understanding their complex evolution and provide practical information for improving agricultural yield. To date, around 350 land plant genomes have been sequenced. The desire for more plant genome sequences has recently been highlighted with the announcement of the 10KP project, which aims to ultimately sequence 10,000 plant genomes to resolve the evolution of all the major branches of the plant tree of life. The work here provides images, raw sequencing data, assembled chloroplast genomes, and preliminary nuclear genome assemblies- all freely available. Effectively this work is a digital representation of an entire botanical garden.

An entire botanical garden of genomes
A plant sample that has been prepared and catalogued for imaging. Another form of digital
data that is available as component of the sequencing and sampling data
[Credit: China National GeneBank]

Researchers from the China National GeneBank, BGI, and the Forestry Bureau of Ruili, China have sampled and sequenced 761 samples, representing 689 vascular plant species from 137 families and 49 orders. The plant samples are all from in and around the 500-hectare Botanical Garden in Ruili, a subtropical part of China bordering Myanmar. Being in a biologically rich part of China, the garden is committed to protecting endangered and Chinese-endemic plants, including the preservation and archiving of these germplasm resources to assist with their long-term conservation. This project is the world’s first scientific and systematic attempt to digitize a whole botanical garden based on genomic as well as voucher specimen information.
On the scientific potential of this resource, BGI’s CEO and author on the paper Xun Xu highlights that: “Current understanding of the evolution of plants and their diversity in a phylogenomic context is limited because of the lack of genome-scale information across phylogenetically diverse species. This innovative project integrates a new way of thinking about the digitization of all the plant species to augment evolutionary and ecological research in botanical gardens.”

In total, the researchers produced 54 terabytes of sequencing data, with an average sequencing depth of 60X per species. In addition to the basic challenge of carrying out DNA sequencing on this number of species, another major task was scaling up the species identification, digitizing images of the specimens, and building a new herbarium for their storage at a new China National GeneBank (CNGB) herbarium in Shenzhen. So far, of the 761 specimens, sequence and chloroplast data has enabled the identification of 257 plants at the species level and 504 at the family level. Deep learning has also been successful applied to 181 species to enable them to be identified to the species level.

An entire botanical garden of genomes
The collection of seeds from the sampled plants that will be used for the China Nation GeneBank Herbarium
that is currently under construction [Credit: China National GeneBank]

Author Ting Yang says that this was “the largest amount of data I have ever processed. During the data analyses, I think the biggest challenges was sequence checking and results examination.” This required researchers to individually check each of the 761 sample’s sequencing data, and compare the chloroplast gene sequences with herbarium specimens for species identification.
Another difficulty relating to simply getting to the point of being able to do the sequencing work was collecting all the samples. Author Jinpu Wei states: “We cooperated with experts from the Ruili Forestry Bureau to collect plant materials distributed in the area of Ruili for the establishment of a digital botanical garden. After 45-days of tiring effort, we collected 1,093 plant materials. Although it was challenging for us to transport the materials properly, we finally managed to ensure the high quality of these plant materials for future research.”

Corresponding author, Xin Liu, adds that the project “was a baseline project to fine tune and standardize the sampling, methodologies, and the data accumulation and analyses techniques for large-scale genome projects like the 10KP (10 thousand Plant Genome Project). From this project, we have gained considerable and useful experience for subsequent sample collection, sequencing, and assembly. At the same time, the data produced from this study can be effectively used in subsequent genome projects.”

An entire botanical garden of genomes
Researchers worked with experts from the Ruili Forestry Bureau to collect plant materials growing in the Ruili area.
This was a 45-day effort to collect 1,093 plant samples, in addition to samples, geographic coordinates
were recorded for future assessment [Credit: China National GeneBank]

Despite having constructed only one sequencing library for each species, the authors were able to assemble preliminary genomes for 17 of them, reflecting the quality and reuse potential of the DNA. Researchers at the Chinese University of Hong Kong have already independently assembled the genomes of species of particular interest to them. The potential for the wider research community to study their species of interest, improve other genomes, develop tools and methods, and provide education opportunities for new generations of scientists is enormous.

Lead author Huan Liu added that “Genomic characterization will provide a large amount of basic data for plant genome assembly, which will be an excellent start for the 10KP project. At the same time, it lays a good foundation for the future research on the correlation mechanism from macroscopic ecology and biodiversity to microscopic molecular level.”

To promote more extensive data sharing than just making sequence data available, the researchers are also making the digitized images available and providing access to the herbarium. The Herbarium (HCNGB) serves as a living plant database that records the position of species grown in the Ruili Botanical Garden and monitors the status of each species.

All the digital data generated here (images, raw sequencing data, assembled chloroplast genomes, and preliminary nuclear genome assemblies) are available via the NCBI SRA, GigaScience GigaDB database and China National GeneBank CNSA. Additionally, to enable the data to be searched and genomes and species identification to be updated, metadata is indexed and linked via Datacite and GigaDB. And all resources are released without restriction under a CC0 waiver. Author Dr Sunil Kumar Sahu highlighted that this is the most important legacy of the project “This dataset is of great value to plant researchers, and more importantly, can serve as a reference for future planetary-scale genome sequencing projects including the Earth BioGenome Project (EBP) and 10 thousand Plant Genome Project (10KP).”

Source: Gigascience [January 24, 2019]



DNA helix may have arisen with startling ease

Trying to explain how DNA and RNA evolved to form such neat spirals has been a notorious enigma in science. But a new study suggests the rotation may have occurred with ease billions of years ago when RNA’s chemical ancestors casually spun into spiralled strands.

DNA helix may have arisen with startling ease
Artwork for the study shows the chemical structure of the helix that self-assembled in the lab,
producing surprisingly bountiful results [Credit: Georgia Tech/Nick Hud]

In the lab, researchers at the Georgia Institute of Technology were surprised to see them do it under conditions thought to be common on Earth just before first life evolved: in plain water, with no catalysts, and at room temperature.

The neat spiraling also elegantly integrated another compound which today forms the backbone of RNA and DNA. The resulting structure had features that strongly resembled RNA.

Pivotal twists

The study has come a step closer to answering a chicken-egg question about the evolutionary path that led to RNA (from which DNA later evolved): Did the spiral come first, and did this structure influence which molecular components made it later into RNA because they fit well into the spiral?

“The spiraling could have had a reinforcing effect. It could have facilitated the molecules getting connected together that have the same chirality (curve) to connect into a common backbone that is compatible with the helical twist,” said the study’s principal investigator Nicholas Hud, a Regents Professor in Georgia Tech’s School of Chemistry and Biochemistry.

The researchers published the new study in the journal Angewandte Chemie in December 2018. The research was funded by the National Science Foundation and the NASA Astrobiology Program under the Center for Chemical Evolution. The center is headquartered at Georgia Tech, and Hud is its principal investigator.

The study’s resulting polymers were not RNA but could be have been an important intermediate step in the early evolution of RNA. For building blocks, the researchers used base molecules referred to as “proto-nucleobases,” highly suspected to be precursors of nucleobases, main components that transport genetic code in today’s RNA.

Nucleobase paradox

The study had to work around a paradox in chemical evolution:

Making RNA or DNA using their actual nucleobases in the lab without the aid of the enzymes of living cells that usually do this job is more than a herculean task. Thus, although RNA and DNA are ubiquitous on Earth now, their evolution on pre-life Earth would appear to have been an anomaly requiring erratic convergences of extreme conditions.

By contrast, the Georgia Tech researchers’ model of chemical evolution holds that precursor nucleobases self-assembled easily to into ancestral prototypes — that were polymer-like and referred to as assemblies — which later evolved into RNA.

“We would call these ‘proto-nucleobases’ or ‘ancestral nucleobases,'” Hud said. “For our overall model of chemical evolution, we’re saying that these proto-nucleobases, which self-assemble into these long strands, could have been part of a very early stage before modern nucleobases were incorporated.”

One main suspected proto-nucleobase in this experiment — and in previous experiments on the possible the evolution of RNA — was triaminopyrimidine (TAP). Cyanuric acid (CA) was another. The researchers highly suspect TAP and CA were parts of a proto-RNA.

The chemical bonds that hold together assemblies of the two suspected proto-nucleobases were surprisingly strong but non-covalent, which is akin to connecting two magnets. In RNA the main bonds holding together modern nucleobases are covalent bonds, akin to welding, and enzymes make those bonds in cells today.

Helical biases

A helix can spiral two ways, left-handed or right-handed. In chemistry, a molecule can also be handed, or chiral, making for “L” or “D” forms of the molecule.

Incidentally, the building blocks of today’s RNA and DNA are all the D form, which make a right-handed helix. Why they evolved like this is still a mystery.

DNA helix may have arisen with startling ease
A proto-nucleobase next to a nucleobase. Hard to tell the difference
[Credit: Georgia Tech/Fitrah Hamid]

Batches of TAP and CA the researchers started out with produced roughly equal amounts of right and left-handed helices, but something stood out: Whole regions of a batch were biased in one direction and were separate from other regions that spiraled mostly the other way.

“The propensity for the molecules to choose one helical direction was so strong that large regions of the batches were made up predominantly of assemblies that were unidirectionally twisted,” Hud said.

This was surprising because the individual molecules of TAP and CA had no chirality of their own, neither L nor D. Still, the twists had a preferred direction.

‘world record’

The researchers added two more experiments to test how strongly their RNA-like assemblies preferred making one-handed helices.

First, they introduced a smidgeon of compounds similar to TAP and CA, but which had L or D chirality, to nudge the spiraling direction. The whole batch conformed to the chirality of the respective additive, resulting in assemblies twisting in a unified direction as helices do in RNA and DNA today.

“It was the new world record for the smallest amount of a chiral dopant (additive) that would flip a whole solution,” said Suneesh Karunakaran, the study’s first author and a graduate researcher in Hud’s lab. “This demonstrated how easy it would be in nature to get abundant amounts of unified helices.”

Second, they put the sugar compound ribose-5-phosphate together with TAP to more closely emulate the current building blocks of RNA. The ribose fell into place, and the resulting assembly spiraled in a direction dictated by the ribose chirality.

“This molecule easily formed an RNA-like assembly that was surprisingly stable, even though the pieces were only held together by non-covalent bonds,” Karunakaran said.

Evolution revolution

The study’s results under such simple conditions represent a leap forward in experimental evidence for how the helical twist of biomolecules could have already been in place long before life emerged.

The research also expands a growing body of evidence supporting an unconventional hypothesis by the Center for Chemical Evolution, which dispenses with the need for a narrative that rare cataclysms and unlikely ingredients were necessary to produce life’s early building blocks.

Instead, most biomolecules likely arose in several gradual steps, on quiet, rain-swept dirt flats or lakeshore rocks lapped by waves. Precursor molecules with the right reactivity enabled those steps readily and produced abundant materials for further evolutionary steps.

Basement engineer

In the lab, helix self-assemblage was so productive that it outstripped a detection device’s capacity to examine the output. Regions a square millimeter or more in size were packed with unidirectionally spiraled polymer-like assemblies.

“To look at them I had to make adjustments to the equipment,” said Karunakaran. “I punched holes in a foil and put it in front of the beam of our spectropolarimeter.”

That worked but needed improvement, so Hud took to his basement at home to build an automated scanner that could handle the experiment’s bountiful results. It revealed large regions of helices with the same handedness.

Source: Georgia Institute of Technology [January 24, 2019]



Research shows what it takes to be a giant shark

In a paper published by Evolution, research led by Swansea University’s Dr Catalina Pimiento and co-authored by an international team of scientists from the UK, Europe and the USA examined the biological traits of all sharks and rays before running a series of evolutionary models to seek how gigantism evolved over time.

Research shows what it takes to be a giant shark
Megalodon compared to a bus [Credit: Guillermo Torres. Banco de Imagenes Ambientales (BIA),
Instituto Alexander von Humboldt]

The results showed that for a shark to be giant, it would need to first evolve adaptations that enhance feeding such as the ability to control — at least to some degree — their own body temperature or become a filter feeder.

One of the most famous giant sharks, Megalodon — the topic of 2018 Hollywood film The Meg — was an active predator that could measure up to 18 metres in length and became extinct around two million years ago.

Meanwhile, the whale shark — which is still around today — can also reach 18 metres but isn’t an active predator. Instead, it is a filter feeder and eats tiny plankton from the sea.

These two subjects formed key parts of the research, which centred on the tree of life for sharks, where the authors mapped characteristics relating to body size, like their thermo-regulatory capacity, feeding mechanism and diet.

Research shows what it takes to be a giant shark
Body size of sharks and rays mapped in their tree of life [Credit: Dr Catalina Pimiento,
Juan L. Cantalapiedra, Kenshu Shimada, Daniel J. Field, Jeroen B. Smaers]

Researchers then found that sharks could become giants by following one of two possible evolutionary pathways; the mesothermic pathway, which consists of evolving the ability to self-control the temperature of their most important organs — or the filter-feeding pathway, which consists of evolving the ability to feed on microscopic plankton.

The mesothermic adaptation allows sharks to live in different types of habitats — including cold waters — and also hunt more effectively. The filter-feeding adaptation allows sharks to eat the most abundant food in the ocean — plankton.

However, there are risks involved for any shark following the evolutionary pathways that lead to gigantism. The mesothermic species need to consume big prey to maintain their high energetic demands, but when these prey are scarce, giant sharks are more susceptible to extinction. The scarcity of large prey in times of rapid climatic change was the most likely cause of the extinction of Megalodon.

While the filter feeders have shown more resilience, they are at risk of eating large volumes of toxic micro plastics that now can be found in the world’s oceans — thus threatening their extinction.

Dr Catalina Pimiento, lead researcher and Postdoctoral fellow at Swansea University, said: “Sharks provide an ideal case study to understand the evolutionary pathways leading to gigantism in the oceans because they display contrasting lifestyles and adaptations, and because they have an evolutionary history of at least 250 million years.”

Source: Swansea University [January 24, 2019]



Ancient funeral mask uncovered at Florida coast

Archaeologists have discovered a rare death mask dating back thousands of years on a beach in Florida, a sign that more treasures may be nearby.

Ancient funeral mask uncovered at Florida coast
The Incan funerary mask made from metals extracted from meteorites has been found 
washed up on a Florida beach [Credit: Fox35]

A team of researchers with Seafarer Exploration Corporation found the artifact made of precious metal on Melbourne Beach and believe it served as part of a funeral headpiece from a pre-Incan civilization in Peru, Fox 35 reported.
“This is some of the earliest evidence of man’s ability to metal-work and to use iridium,” Dr. Michael Torres, who found the mask, told Fox35.  “That changes things, and may change the way we perceive ancient Peruvian cultures.”

Torres is working with a team to discover artifacts from the 1715 shipwreck of the La Concepcion. Researchers believe the mask was taken by Spanish tomb raiders and washed up after the wreck.
The discovery of the mask hints that more precious items could be nearby. Torres said that he hopes to give the mask to a museum as a gift.

Author: Paulina Dedaj | Source: Fox News [January 24, 2019]



Four fragments of looted frescoes repatriated to Cyprus

Four fragments of religious frescoes removed from churches in the north following the 1974 Turkish invasion on Monday were handed over to the Republic in the Netherlands after they were recovered by international NGO Walk of Truth.

Four fragments of looted frescoes repatriated to Cyprus
Credit: Department of Antiquities, Republic of Cyprus

Two of the frescoes have been identified as belonging to the church of Panayia Absinthiotissa, a monastery at Syhari, near Kyrenia.
They are a portrayal of Virgin Mary attending the deposition of Christ and an image of a martyr.

The provenance of one of the other two frescoes is not known, but it has also been identified as Cypriot.

Four fragments of looted frescoes repatriated to Cyprus
Credit: Department of Antiquities, Republic of Cyprus

The monastery, founded in the 11th or 12th centuries as a Byzantine foundation, took its name from the absinth that grows in the area.
During the Ottoman years, the monastery became the property of the Greek Orthodox Patriarchate of Jerusalem.

Transport Minister Vassiliki Anastasiadou, who travelled to the Hague to collect the frescoes, said one of them came from the church of the Virgin Mary in Assia, Famagusta.

Four fragments of looted frescoes repatriated to Cyprus
Credit: Department of Antiquities, Republic of Cyprus

The 15th century church was entirely lined with frescoes initially and until 1974 some were still preserved high on the east wall, portraying saints and prophets.
The iconostasis was destroyed during or after the invasion and the 17th century carved wooden cross and the frescoes were stolen.

The church is being restored by the bicommunal technical committee for culture.

Four fragments of looted frescoes repatriated to Cyprus
Credit: Department of Antiquities, Republic of Cyprus

More than 500 churches situated in the areas under Turkish occupation since 1974 have been destroyed, plundered and looted or turned into stables, warehouses, restaurants and hotels.

Source: Cyprus Mail [January 24, 2019]




https://t.co/hvL60wwELQ — XissUFOtoday Space (@xufospace) August 3, 2021 Жаждущий ежик наслаждается пресной водой после нескольких дней в о...