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Shedding light on Australia’s polar dinosaurs

The fossil bone tissue reveals new information about how the Australian “hypsilophodontid” dinosaurs lived
The fossil bone tissue reveals new information about how the Australian “hypsilophodontid” dinosaurs lived. Credit: Peter Trusler

Dinosaurs that lived in what is now known as Victoria more than 120 million years ago would have dealt with prolonged periods of darkness and below freezing temperatures, a new study reveals.

The study, published in the Scientific Reports journal, examines the bone tissue microstructure of plant-eating “hypsilophodontid” dinosaurs known to have lived in the Antarctic Circle—now Victoria, Australia.

“These little dinosaurs would have dealt with prolonged periods of darkness and mean annual temperatures near freezing, and certainly below freezing in the winter,” says one of the study authors, Dr. Patricia Vickers-Rich, a professor of paleobiology at Swinburne.

In studying fossils from seventeen individuals, the International research team from Swinburne University of Technology, Oklahoma State University, Museums Victoria, and Monash University produced the first life history reconstructions for these small Australian polar dinosaurs.

Examining bone microstructure

An examination of the bone microstructure, or histology, of the hypsilophodontid fossils revealed many characteristics of their growth.

Rings in the bone, similar in appearance to tree rings, helped determine individual age. Bone fibre orientation, blood vessel density, and the amount of bone between growth rings, was used to determine annual growth rates.

Bone histology revealed that, in general, growth was most rapid during the first three years of life, and the dinosaurs were fully grown – the size of a medium wallaby or average turkey—in five to seven years.

Uncovering Australia’s past

The hypsilophodontid samples were recovered from two Australian localities along the south Victorian coast stretching from west of Cape Otway to Inverloch, geologically separated by about 12 million years.

However, the trend of rapid growth for three years followed by adult body size between five and seven years, was conserved across the two samples.

“Given the geologic time involved, we may be looking at several polar dinosaur species in this sample, but their growth trajectories are so similar that we cannot differentiate them from one another based on their growth patterns and rates alone,” says Holly Woodward (Oklahoma State University).

“Instead, our life history assessment demonstrates to us that this generalised growth trajectory was a successful lifestyle for surviving in a region experiencing unique conditions.”

Histologic examinations

The tibia (shin-bone) of one hypsilophodontid individual in the sample had clearly suffered from a pathologic condition known as osteomyelitis or bone infection.

Microscopic examination revealed the cause of this pathology was most likely a broken bone, which then became infected. Counting the growth rings preserved in this tibia prior to the formation of the pathologic bone, the team was able to place the timing of the injury as having occurred when this individual was approximately four years old.

The team was also able to tease out how long this little dinosaur lived and how it dealt with the injury: histologic examination of the unaffected femur (thigh bone) of this individual shows that it survived with the injury and pathology for three more years.

“Further investigations of this unique sample will continue to shed light on how these little dinosaurs thrived in high latitudes and under the most stressful of environments during a time when dinosaurs flourished on planet Earth,” Dr. Vickers-Rich says.

Reference:
Holly N. Woodward et al. The bone microstructure of polar “hypsilophodontid” dinosaurs from Victoria, Australia, Scientific Reports (2018). DOI: 10.1038/s41598-018-19362-6

Note: The above post is reprinted from materials provided by Swinburne University of Technology.

Tidal cycles could help predict volcanic eruptions

Ruapehu Volcano
Ruapehu Volcano. Credit: Greg Steenbeeke

Just before a surprise eruption of New Zealand’s Ruapehu volcano in 2007, seismic tremor near its crater became tightly correlated with twice-monthly changes in the strength of tidal forces, a new study has found. The research, published in the journal Scientific Reports, suggests that signals associated with tidal cycles could potentially provide advanced warning of certain types of volcanic eruptions.

“Looking at data for this volcano spanning about 12 years, we found that this correlation between the amplitude of seismic tremor and tidal cycles developed only in the three months before this eruption,” said Társilo Girona, the study’s lead author. “What that suggests is that the tides could provide a probe for telling us whether or not a volcano has entered a critical state.”

Girona, a NASA postdoctoral fellow at the Jet Propulsion Laboratory, led the research during a postdoctoral appointment at Brown University, working with Brown professor Christian Huber and Corentin Caudron, a postdoctoral researcher at the Ghent University in Belgium.

Earth’s tides rise and fall daily due to the gravitational tug of the Moon as the Earth rotates. During full and new Moons, the lunar gravitational pull lines up with that of the sun, which makes the daily tidal bulges a little larger during those Moon phases. During the first- and third-quarter Moons, the daily tidal bulge is a little smaller. This twice-monthly change in tidal amplitude is sometimes referred to as the fortnightly tide. While we normally think of tides in terms of rising and falling waters, these gravitational stresses also affect the planet’s solid crust. The question of whether gravitational stresses may influence volcanic activity is longstanding in the Earth sciences.

“A lot of research has been focused on whether or not tidal forces can trigger eruptions, and there’s no definitive evidence whatsoever that they do,” Huber said. “We wanted to take a different angle with this study and look at whether there’s some detectable signal associated with tidal forces that can tell us something about a volcano’s criticality.”

The researchers chose to study Ruapehu volcano in part because its activity has been closely monitored for years by GNS Science, a research institute in New Zealand. The mountain is a popular tourist attraction and home to two ski resorts, so officials want to be aware of any warning signs that it might erupt. That monitoring provided a long and continuous data set for the researchers to study.

In particular, the team was interested in data from seismic sensors located near the volcano’s crater. Those sensors pick up volcanic tremor, a low-level seismic rumble that provides a persistent signal of activity within a volcanic system. Using a sophisticated statistical technique, the researchers combed through 12 years of seismic data, looking for any period when the seismicity was correlated with lunar cycles. They found that for most of those 12 years, there was no correlation between tremor and lunar cycles, except the few months before a steam-driven eruption on Sept. 25, 2007, when a strong correlation emerged.

During those three months, the amplitude of tremor rose and fell ever so slightly in lock step with the fortnightly tidal cycle. While the fluctuations in seismic amplitude were subtle, the strength of the correlation to the tidal cycle was not. The correlation was as strong as 5 sigma, the researchers say, meaning that the probability that pattern arose by chance is about one in 3.5 million.

To understand how tidal forces were affecting Ruapehu during those three months, the researchers used a model of seismic tremor that they had developed previously. Volcanoes like Ruapehu have a vertical conduit through which lava rises, and a solid rock plug at the top. Gases released from the lava form a pocket between the rocky plug and the lava pool. That gas pocket can resonate against the plug, which creates seismic tremor.

The model suggests that when the pressure of the gas pocket reaches a critical level — a level at which a steam eruption is possible — the differing stresses associated with changing tidal forces are enough to change the amplitude of tremor.

“That’s what we think was happening in 2007,” Huber said. “When the pressure in the system became critical, it became sensitive to the tides. We were able to show that the signal is detectable.”

None of the other indicators geologists typically use to anticipate eruptions raised any warning flags in 2007. So a tidal signal could be a way of predicting steam-driven eruptions, which are otherwise hard to predict.

“We’d like to collect more data from other eruptions and other volcanos to see if this tidal signal shows up elsewhere,” Huber said. “Then we can start to think about using it as a potential means of predicting future eruptions of this kind.”

The research was funded by the National Science Foundation (1454821).

Reference:
Társilo Girona, Christian Huber, Corentin Caudron. Sensitivity to lunar cycles prior to the 2007 eruption of Ruapehu volcano. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-018-19307-z

Note: The above post is reprinted from materials provided by Brown University.

Tiny crystals could help predict volcanic eruptions

Stromboli Volcano
Stromboli Volcano. Credit: John Caulfield

They can be as small as a grain of salt, but tiny crystals that form deep in volcanoes may be the key for advance warnings before volcanic eruptions.

University of Queensland vulcanologist Dr Teresa Ubide said the research provided new information that could lead to more effective evacuations and warning communications.

“This could signal good news for the almost one in 10 people around the world who live within 100km of an active volcano,” she said.

“We haven’t yet reached the ‘holy grail’ of being able to predict volcanic eruptions, but our research is a significant step forward in understanding the processes that lead to eruption.”

Dr Ubide, from UQ’s School of Earth and Environmental Sciences, used a new laser technique to examine the composition of tiny crystals forming deep in volcanoes.

The crystals are created when molten rock — magma — from up to 30 km beneath a volcano starts to move upwards towards the Earth’s surface.

The crystals are carried in the erupting magma, continuing to crystallise and change in composition on the way to the surface.

“They effectively ‘record’ the processes that happen deep in the volcano right before the eruption starts,” says Dr Ubide.

“We’ve found by studying these crystals in a specific volcano that, when new magma arrives at depth, up to 90 per cent of the time it can trigger an eruption, and within only two weeks.”

From this, vulcanologists hope to work out how to better monitor volcanoes — for instance, at what depths underground to look for signs of magma movement before an eruption.

Dr Ubide said it was currently very difficult to predict volcanic eruptions — as evidenced by the eruption at Mount Agung in Bali, which started last November after 2 months of precursory earthquakes.

“The Bali eruption led to the evacuation of more than 70,000 people and caused massive disruptions in air traffic and tourism, affecting more than 100,000 travellers,” she said.

“Volcanic ash and gas clouds rose to heights of up to 4 km above the summit and produced ash-fall in downwind areas.

“Lahars (mudflows) impacted houses, roads and agricultural areas.

“Every volcano is different and requires individual monitoring.”

Dr Ubide’s team tracked eruptions, their triggers and time scales at Mount Etna, on Sicily in Italy, Europe’s most active volcano.

The results could provide important information for future volcanic monitoring efforts at the site, she said.

“We plan to apply the same approach to other volcanoes around the world, especially for countries neighbouring Australia like Indonesia and New Zealand,” she says.

Reference:
Teresa Ubide, Balz S. Kamber. Volcanic crystals as time capsules of eruption history. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-017-02274-w

Note: The above post is reprinted from materials provided by University of Queensland.

New Eocene fossil data suggest climate models may underestimate future polar warming

Foraminifera, small single-celled marine organisms
Foraminifera, small single-celled marine organisms, form their shells in concert with the ocean’s temperature and chemistry. Like tiny time capsules, they can reveal the climate conditions of millions of years ago. Credit: Laura Cotton

A new international analysis of marine fossils shows that warming of the polar oceans during the Eocene, a greenhouse period that provides a glimpse of Earth’s potential future climate, was greater than previously thought.

By studying the chemical composition of fossilized foraminifera, tiny single-celled animals that lived in shallow tropical waters, a team of researchers generated precise estimates of tropical sea surface temperatures and seawater chemistry during the Eocene Epoch, 56-34 million years ago. Using these data, researchers fine-tuned estimates from previous foram studies that captured polar conditions to show tropical oceans warmed substantially in the Eocene, but not as much as polar oceans.

Importantly, when modern climate models — the same as those used in the United Nations’ recent Intergovernmental Panel on Climate Change reports — were run under Eocene conditions, many could not replicate these findings. Instead, the models consistently underestimated polar ocean warming in the Eocene.

This discrepancy may result from a gap in our understanding of the climate system or from what we know about the Eocene, said David Evans, the study’s lead author and Leverhulme Research Fellow at the University of St Andrews’ School of Earth and Environmental Sciences. If it does indeed relate to the climate system, it raises the possibility that predictions of future polar warming are also too low.

“Yes, the tropics are warming but nowhere near to the same degree as the polar regions,” Evans said. “That’s something we really need to be able to understand and replicate in climate models. The fact that many models are unable to do that at the moment is worrying.”

The researchers published their findings this week in the Proceedings of the National Academy of Sciences.

Scientists frequently look to the Eocene to understand how the Earth responds to higher levels of carbon dioxide. During the Eocene, the concentration of carbon dioxide in the atmosphere was more than 560 parts per million, at least twice preindustrial levels, and the epoch kicked off with a global average temperature more than 8 degrees Celsius — about 14 degrees Fahrenheit — warmer than today, gradually cooling over the next 22 million years. These characteristics make the Eocene a good period on which to test our understanding of the climate system, said Laura Cotton, study co-author and curator of micropaleontology at the Florida Museum of Natural History.

One of the challenges has been accurately determining the difference between sea surface temperatures at the poles and the equator during the Eocene, with models predicting greater differences than data suggested.

The research team used large bottom-dwelling forams as “paleothermometers” to gain a more precise temperature reading. Forams have an exceptionally long fossil record, spanning more than 540 million years, and they are often well-preserved in ocean sediments. Most are small enough to fit into the eye of a needle — Cotton describes them as “an amoeba with a shell” — but they were so abundant during the Eocene that there are entire rocks composed of them.

“If you look at the pyramids, they’re full of these tiny little lentil-like things — those are forams,” Cotton said. “The ancient Greeks thought the pyramids were made from the fossilized lentils of slaves, but it’s just the limestone from one of these deposits that is absolutely filled with them.”

Forams form their shells in concert with ocean temperatures and chemistry, acting as miniscule time capsules, each containing a precise record of the temperature and ocean chemistry during its lifetime. Their shells are primarily made of calcium, carbon and oxygen. Heavy isotopes of carbon and oxygen bond together as a foram makes its shell — the cooler the temperature, the more they bond to each other.

By analyzing these clumped isotopes from fossil specimens found in India, Indonesia and Tanzania, the researchers could get an accurate reading of sea surface temperature across the tropics in the Eocene. They also lasered a small hole in each specimen to measure the amount of magnesium and calcium that vaporized, revealing the seawater chemistry.

They found that tropical sea surface temperature in the Eocene was about 6 degrees Celsius — about 10 degrees Fahrenheit — warmer than today.

“This was the first time we had samples that were good enough and this method was well-known enough that it could all come together,” Cotton said.

The team then used their dataset from the tropics to back-calculate the temperature and chemistry of polar oceans, relying on previous studies of forams that captured the conditions of those regions.

With this correction factor in place, they investigated the degree to which polar oceans warmed more than the tropics, a feature of the climate system known as polar amplification. Their data showed that the difference between polar and equatorial sea surface temperatures in the Eocene was an estimated 20 degrees Celsius, about 36 degrees Fahrenheit. Today the difference is 28 degrees Celsius, indicating that polar regions are more sensitive to increases in atmospheric carbon dioxide than the tropics.

Troublingly, said Evans, when the team compared their data with various modern climate models under Eocene conditions, most models underestimated polar amplification by about 50 percent.

The two models that came closest to reproducing the team’s data had one key aspect in common — they modified the way they accounted for cloud formation and the longevity of clouds in the atmosphere, particularly in the polar regions.

“To us, that looks like a promising research direction,” he said. “If — and it’s a big if — that turns out to be the right avenue to go down, that could play into the models we use for our future climate predictions.”

Reference:
David Evans, Navjit Sagoo, Willem Renema, Laura J. Cotton, Wolfgang Müller, Jonathan A. Todd, Pratul Kumar Saraswati, Peter Stassen, Martin Ziegler, Paul N. Pearson, Paul J. Valdes, Hagit P. Affek. Eocene greenhouse climate revealed by coupled clumped isotope-Mg/Ca thermometry. Proceedings of the National Academy of Sciences, 2018; 201714744 DOI: 10.1073/pnas.1714744115

Note: The above post is reprinted from materials provided by Florida Museum of Natural History.

New 508-million-year-old bristle worm species from British Columbia’s Burgess Shale wiggles into evolutionary history

Kootenayscolex barbarensis
Life reconstruction of Kootenayscolex barbarensis. Credit: Danielle Dufault, 2018 © Royal Ontario Museum

Researchers at the Royal Ontario Museum and the University of Toronto have described an exceptionally well-preserved new fossil species of bristle worm called Kootenayscolex barbarensis. Discovered from the 508-million-year-old Marble Canyon fossil site in the Burgess Shale in Kootenay National Park, British Columbia, the new species helps rewrite our understanding of the origin of the head in annelids, a highly diverse group of animals which includes today’s leeches and earthworms. This research was published today in the journal Current Biology in the article A New Burgess Shale Polychaete and the Origin of the Annelid Head Revisited.

“Annelids are a hugely diverse group of animals in both their anatomies and lifestyles,” said Karma Nanglu, a University of Toronto PhD candidate, and a researcher at the Royal Ontario Museum, as well as the study’s lead author. “While this diversity makes them ecologically important and an evolutionarily interesting group to study, it also makes it difficult to piece together what the ancestral annelid may have looked like.”

Annelids are found in nearly all marine environments from hydrothermal vents to coral reefs to the open ocean, and also include more evolutionary derived species living on land today. Although quite abundant in modern environments, their early evolutionary history, in particular the origin of their heads, is confounded by a relatively poor fossil record, with few species described from well-preserved body fossils near the evolutionary origins of the group.

Co-author Dr. Jean-Bernard Caron, Senior Curator of Invertebrate Palaeontology at the Royal Ontario Museum, Associate Professor in the departments of Ecology & Evolutionary Biology and Earth Sciences at U of T, and Nanglu’s PhD supervisor, said: “While isolated pieces of annelid jaws and some annelid tubes are well known in the fossil record, preservation of their soft tissues is exceedingly rare. You need to look to truly exceptional fossil deposits like those found in the 508-million-year-old Burgess Shale locality in British Columbia to find well preserved body fossils. Even then, they’re quite uncommon and many of the currently described species there are still poorly understood.”

One key feature of the new Burgess Shale worm Kootenayscolex barbarensis is the presence of hair-sized bristles called chaetae on the head which led Nanglu and Caron to propose a new hypothesis regarding the early evolution of the head in annelids. “Like other bristle worms, Kootenayscolex possesses paired bundles of hair-sized bristles spread along the body; this is in fact one of the diagnostic features of this group of animals,” Nanglu added. “However, unlike any living forms, these bristles were also partially covering the head, more specifically surrounding the mouth. This new fossil species seems to suggest that the annelid head evolved from posterior body segments which had pair bundles of bristles, a hypothesis supported by the developmental biology of many modern annelid species.”

The Cambrian Period (541-485 million years ago) represents the first time that most animal groups appear in the fossil record, however, many species often possessed morphologies that were very unlike their modern relatives. “Coupling new fossil discoveries, such as Kootenayscolex, with a deeper understanding of developmental processes presents a powerful tool for investigating these unique morphologies and, ultimately, the origin of modern animal diversity,” added Dr. Caron.

The description of Kootenayscolex is one of many new discoveries from the Burgess Shale site called Marble Canyon (Kootenay National Park) which are changing the way we think about the evolution of a wide array of animal groups. Dr. Caron led the ROM research team that uncovered this new locality in 2012, 40 km southeast of the original Burgess Shale site (Yoho National Park) in the Canadian Rockies. This new bristle worm is not only the most abundant species of annelid throughout the entire fossil record with more than 500 specimens recovered, but also the best preserved so far. “Some specimens preserved remnants of internal tissues, including possible nervous tissues, which is the first time we see evidence of such delicate features in a fossil annelid. This exceptional preservation opens a new chapter in the study of these ancient worms” added Caron.

“508 million years ago, the Marble Canyon would have been teeming with annelids,” said Nanglu. “The fine anatomical details preserved in Kootenayscolex allow us to infer not only its evolutionary position, but also its lifestyle. Sediment preserved inside their guts suggest that, much as their relatives do in modern ecosystems, these worms served an important role in the food chain by recycling organic material from the sediment back to other animals that preyed on them.”

The new annelid’s species name, barbarensis, was chosen to honour Barbara Polk Milstein, who is a Royal Ontario Museum volunteer and longtime supporter of Burgess Shale research. Kootenayscolex barbarensis is brought to life by ROM visual artist and scientific illustrator Danielle Dufault.

Reference:
Karma Nanglu et al. A New Burgess Shale Polychaete and the Origin of the Annelid Head Revisited. Current Biology, 2017 DOI: 10.1016/j.cub.2017.12.019

Note: The above post is reprinted from materials provided by Royal Ontario Museum.

Heat loss from the Earth triggers ice sheet slide towards the sea

Several glaciers flow into the area of Young Sound where researchers have shown that heat from the Earth's interior warms up the bottom water of the fjord.
Several glaciers flow into the area of Young Sound where researchers have shown that heat from the Earth’s interior warms up the bottom water of the fjord. Credit: Mikael Sejr

Greenland’s ice sheet is becoming smaller and smaller. The melting takes place with increased strength and at a speed that no models have previously predicted.

Today, in the journal Scientific Reports, researchers from the Arctic Research Centre, Aarhus University, and the Greenland Institute of Natural Resources present results that, for the first time, show that the deep bottom water of the north-eastern Greenland fjords is being warmed up by heat gradually lost from the Earth’s interior. And the researchers point out that this heat loss triggers the sliding of glaciers from the ice sheet towards the sea.

Icelandic conditions

“North-East Greenland has several hot springs where the water becomes up to 60 degrees warm and, like Iceland, the area has abundant underground geothermal activity,” explains Professor Soren Rysgaard, who headed the investigations.

For more than ten years, the researchers have measured the temperature and salinity in the fjord Young Sound, located at Daneborg, north of Scoresbysund, which has many hot springs, and south of the glacier Nioghalvfjerdsfjorden, which melts rapidly and is connected to the North-East Greenland Ice Stream (NEGIS).

By focusing on an isolated basin in the fjord with a depth range between 200 and 340 m, the researchers have measured how the deep water is heated over a ten-year period. Based on the extensive data, researchers have estimated that the loss of heat from the Earth’s interior to the fjord is about 100 MW m-2. This corresponds to a 2 megawatt wind turbine sending electricity to a large heater at the bottom of the fjord all year round.

Heat from the Earth’s interior — an important influence

It is not easy to measure the geothermal heat flux — heat emanating from the Earth’s interior — below a glacier, but within the area there are several large glaciers connected directly to the ice sheet. If the Earth releases heat to a fjord, heat also seeps up to the bottom part of the glaciers. This means that the glaciers melt from below and thus slide more easily over the terrain on which they sit when moving to the sea.

“It is a combination of higher temperatures in the air and the sea, precipitation from above, local dynamics of the ice sheet and heat loss from the Earth’s interior that determines the mass loss from the Greenland ice sheet,” explains Soren Rysgaard.

“There is no doubt that the heat from the Earth’s interior affects the movement of the ice, and we expect that a similar heat seepage takes place below a major part of the ice cap in the north-eastern corner of Greenland,” says Soren Rysgaard.

The researchers expect that the new discoveries will improve the models of ice sheet dynamics, allowing better predictions of the stability of the Greenland ice sheet, its melting and the resulting global water rise.

Reference:
Søren Rysgaard, Jørgen Bendtsen, John Mortensen, Mikael K. Sejr. High geothermal heat flux in close proximity to the Northeast Greenland Ice Stream. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-018-19244-x

Note: The above post is reprinted from materials provided by Aarhus University.

Arsenic and permafrost microbes help hunt for life on Mars

Bacteria survive in the harsh conditions of the Andean lakes of Argentina among high concentrations of arsenic.
Bacteria survive in the harsh conditions of the Andean lakes of Argentina among high concentrations of arsenic. Credit: ASLIFE project

Studying environments that are similar to Mars, and their microbial ecosystems, could help prepare biologists to identify traces of life in outer space.

In some of the most remote areas of our planet, scientists are examining how life can persist in the form of tiny microbes that inhabit a niche that would be fatal to the vast majority of organisms on Earth.

Living off toxic substances like arsenic, or in oxygen-free zones, these hardy microbes metabolise food and nutrients in completely different ways from most plants, animals and humans. Some move and metabolise so slowly, for example, that until recently scientists did not even consider them to be alive.

The harsh environments where they live are similar to conditions found on Mars and other planets, and by furthering our understanding of how these microbial communities work, space geobiologists will be better equipped to identify signs of extra-terrestrial life.

Dr. Amedea Perfumo of the GFZ German Research Centre for Geosciences leads the EU-funded BIOFROST project, which is investigating how organisms survive in the deep biosphere of Earth’s permafrost, where temperatures are sub-zero and there is a lack of oxygen.

‘These anoxic and frozen conditions are extremely relevant for space exploration. It’s an analogue for Mars,’ she said. ‘It’s about finding what the limits for life on Earth are under the most similar conditions to space and seeing if we can have a better interpretation of what might come out from a space mission.’

BIOFROST focused on building up a so-called on-filter analytic pipeline, where information about live bacteria, such as how many there are of which type, how active they are and how they interact with each other are extracted from the permafrost sediment and collected onto a special gold-platinum-coated filter.

‘I am supported by some of the most forefront techniques, which include NanoSIMS and nano-spectroscopy, and I hope, in particular, to provide scientific evidence to the basic functioning of a cell under such extreme conditions and how this impacts on the permafrost’s ecosystem functioning,’ said Dr. Perfumo.

Adaptations

The permafrost microorganisms being studied by Dr. Perfumo have developed unique adaptations to their freezing, oxygen-free zones. Their metabolism is so slow, for example, that it is only recently that technology has become sophisticated enough to detect that the organisms are even alive.

Ecological adaptation can come at a cost, however. Because they’ve evolved to fit so perfectly into their niche, any kind of temperature change can spell trouble for the organisms. In previous experiments, Dr. Perfumo found that when the heat was turned up by only 5 degrees Celsius, the bacteria died.

This shows a very low tolerance for change in environmental conditions, unlike many other kinds of bacteria. The various species of bacteria that we tend to find at room temperatures, for example, need to be able to survive fluctuating weather conditions, whereas deep permafrost bacteria are generally guaranteed to live at constant, though very cold, temperatures.

Arsenic

High up in the Andean lakes of Argentina, researchers are exploring another so-called extremophile organism – bacteria that survive in high concentrations of arsenic. The World Health Organization recommends that drinking water should have no more than 10 micrograms of arsenic per litre, but these lakes contain four or five orders of magnitude more.

The conditions in fact mimic life on prehistoric Earth. ‘When you are there, it’s like you are on Earth 3 500 million years ago,’ says Dr. Maria Sancho-Tomas of the Institut de Physique du Globe de Paris, France, who leads the ASLIFE project to investigate the bacteria. ‘It’s amazing. If you look at the landscape, it’s like Mars.’

On prehistoric Earth, organisms had to develop strategies to either fight or adapt to the arsenic. Microbes like those being studied by Dr. Sancho-Tomas used arsenic in their metabolic systems, converting the mineral to energy, in a process not unlike the way that humans break down food.

The ASLIFE researchers are analysing earth cores by drilling a hole in the ground and extracting a cylinder of material to take back to the laboratory for further analysis. According to Dr. Sancho-Tomas, the parts of the sediment from the lakes that contain arsenic can clearly be seen – they are purple, as the arsenic interacts with sulphur.

The team is also taking scrapings from stromatolites, ancient organic structures that can be billions of years old and are created by microorganisms. The samples are then taken to synchrotron facilities at the SOLEIL plant near Paris, France, to get a closer look at the inner workings of these organisms.

The idea is to establish whether certain arsenic variants – or isotopes – could be used as biosignatures – chemical indicators that life is, or was, present. If so, space scientists could look for the same signatures on other planets and infer that life existed there, even if the microorganisms themselves remain elusive.

In the process, the researchers are also coming up with new ways of transporting and examining these microbes, samples of which can deteriorate due to factors such as temperature and pressure changes. Astrobiologists will be able to use these methods to ensure that any extraterrestrial samples found will be transported back to Earth unharmed.

Closer to home

However, learning more about extremophiles also has practical applications closer to home. Dr. Perfumo is working on adapting enzymes and molecules with slippery surfaces, known as biosurfactants, from these cold-loving bacteria to lower the temperatures needed for many commercial and industrial activities, which will be beneficial for the environment.

Dr. Sancho-Tomas and her colleagues are making a high-resolution map of the distribution of the arsenic-loving bacteria in the Andes. This information could then be used to determine arsenic-contaminated areas around the world, for example in Vietnam and India.

What’s more, the bacteria they are examining could eventually be used as bioremediators – that is, natural microorganisms that clear environmental pollutants from a site. Further genetic analysis of the arsenic-consuming bacteria will be needed before the relevant enzymes can be identified for this.

Note: The above post is reprinted from materials provided by Horizon: The EU Research & Innovation Magazine.

The seemingly unremarkable crystals that could help predict volcanic eruptions

Panoramic of Mt Etna, Sicily
Panoramic of Mt Etna, Sicily. Credit: Dr Teresa Ubide.

They may look inconspicuous and unremarkable, and most people wouldn’t notice them, but small crystals in volcanic rocks, such as lava, may hold the key to better understanding advance warnings of volcanic eruptions.

The crystals form inside the volcano when molten rock—magma—starts moving upwards from depths of up to 30 km towards the Earth’s surface. The crystals are carried in the erupting magma, and they often continue to grow as they are being transported. Importantly, they also change in composition on their way to the surface.

Two scientists—Dr Teresa Ubide from the University of Queensland, and Professor Balz Kamber from Trinity College Dublin—conducted the research in a project funded mainly by Science Foundation Ireland. They used a laser technique to examine the inside of these crystals in a novel way. And what they discovered is that the crystals contain a memory in the form of growth layers that look similar to tree rings. Reading the history from these layers may lead to more effective volcanic hazard monitoring, including for dormant volcanoes.

Dr Ubide said: “They essentially ‘record’ the processes right before the eruption starts. At Mount Etna, we found that the arrival of new magma at 10 km depth is a very efficient trigger of eruptions—and within only two weeks.”

“In this case, therefore, earth tremors at the depth of magma recharge must be taken as serious signs of potential imminent eruptions. At other volcanoes, the method will allow to establish the relationship between recharge depth, recharge frequency and eruption efficiency. This can then help scientists to better relate physical signs of recharge to eruption potential.”

The findings have just been published in leading international journal Nature Communications. The research was conducted on Mount Etna, in Sicily, which is Europe’s most active volcano. Dr Ubide’s team is now planning to expand the approach to other volcanoes around the world, and to combine the information with geophysical signs of magma movement.

It remains very difficult to predict volcanic eruptions – as evidenced by the eruption at Mount Agung in Bali, which started last November after two months of precursory earthquakes. It led to the evacuation of over 70,000 people and caused massive disruptions in air traffic and tourism, affecting over 100,000 travellers.

Professor of Geology and Mineralogy at Trinity, Balz Kamber, added: “The new approach may also prove useful for studying volcanoes that have remained dormant, such as the currently erupting volcano on Kadovar Island, Papua New Guinea.”

“For many volcanoes there is no eruption history, but geologists can collect lavas from past eruptions and study their crystals.”

Reference:
Teresa Ubide et al, Volcanic crystals as time capsules of eruption history, Nature Communications (2018). DOI: 10.1038/s41467-017-02274-w

Note: The above post is reprinted from materials provided by Trinity College Dublin.

Large volcanic island flank collapses trigger catastrophic eruptions

The summit of the Teida volcano.
The summit of the Teida volcano. Credit: Image courtesy of National Oceanography Centre (NOC)

New research, published today in Nature Scientific Reports, not only implies a link between catastrophic volcanic eruptions and landslides, but also suggests that landslides are the trigger.

At the heart of Tenerife and standing almost 4 km high, Teide is one of the largest volcanoes on Earth. Over a period of several hundred thousand years, the previous incarnations of Teide have undergone a repeated cycle of very large eruptions, collapse, and regrowth. Previous research by scientists at the National Oceanography Centre (NOC) revealed that past eruptions may have been linked to huge multi-stage submarine landslides, based on similar ages and composition of landslide and volcanic deposits.

By studying these landslide deposits further, NOC scientists noticed that material from explosive volcanic eruptions was only found in the uppermost layers of each landslide deposit. This demonstrates that the initial stages of each landslide occurred underwater and before each eruption, whilst in each case the later stages of terrestrial landsliding occurred after the eruption. These results suggest that the initial stages of the landslides may have triggered each of the eruptions.

The scientists then investigated the thin volcanic clay layers between landslide and eruption deposits, and based upon the time required for clay to settle out of the ocean, estimated the minimum time delay between the initial submarine landslide and a subsequent eruption as approximately ten hours.

NOC scientist and lead author of this research, Dr James Hunt, said “Crucially, this new research shows that after the initial submarine landslide there could be between ten hours to several weeks until the eruption is finally triggered — very different from the near-instantaneous landslide triggering of the 1980 Mt St Helens eruption. This information could help inform hazard mitigation strategies for volcanoes similar to Teide, such as Mt St Helens or Montserrat.”

Dr Hunt suggests this delay could be because the shallow magma chamber in Teide does not contain enough volatiles (water) to immediately create explosive eruptions. However, removal of volcanic material by landslides may trigger magma to rise from the lower volatile-rich magma chamber, which mixes with the shallow magma, causing explosive volcanic eruptions after a delay and leaving a large crater-like feature called a caldera that may be several kilometres across. These ‘caldera-forming’ eruptions are among the largest volcanic eruptions on Earth and involve energies equivalent to an atom bomb explosion, while the associated landslides are among the largest mass movements on Earth and can generate potentially damaging tsunamis.

This new understanding of the linkage between large volcanic islands and caldera-forming eruptions will help advise future geohazard assessments of volcanic islands, and forms part of the NOC’s on-going research into marine geohazards.

Reference:
James E. Hunt, Michael Cassidy, Peter J. Talling. Multi-stage volcanic island flank collapses with coeval explosive caldera-forming eruptions. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-018-19285-2

Note: The above post is reprinted from materials provided by National Oceanography Centre (NOC).

Do moon phases produce big earthquakes?

Moon
Moon

Huge earthquakes are not significantly influenced by the moon, a new study says.

The study, conducted by U.S. Geological Survey seismologist Susan Hough, looked at earthquakes of magnitude 8 or greater over the past four centuries. And a review of more than 200 earthquakes demonstrated that there is no connection between the phase of the moon and the time when huge seismic events of magnitude 8 and greater strike.

“That’s obviously a big earthquake myth: that big earthquakes happen on the full moon,” Hough said in an interview. Her study was published Tuesday in the journal Seismological Research Letters, a publication of the Seismological Society of America.

Hough said the myth can gain more attention when a large earthquake strikes on a full moon or when scientific studies show a weak influence on earthquake rates by tidal or other forces.

“In recent years, there have been a couple of nice studies that show that tidal forces do modulate earthquake rates slightly. It makes sense: The tides create stress in the solid earth, and not just the oceans. And in some cases, that small force can be ‘the straw that breaks that camel’s back’ and nudges the fault to produce an earthquake,” Hough said.

But it’s also important to understand that “this isn’t of any practical value for prediction,” Hough said.

“A recent study … for example, concluded that very large earthquakes, with magnitudes close to 9, tend to occur near the time of maximum tidal stress,” Hough said in her study, adding that researchers “point out, however, that the relationship is not clear-cut and does not hold when low-magnitude events are included in the analysis.”

Indeed, other scientists who have authored studies on the impact of tides with earthquakes have been careful to point out that many earthquakes will still happen when tidal stress is low, and note that the studies don’t mean that the public can get a warning about the exact date, time and location of the next big earthquake.

But sometimes reports of those studies, Hough said, “turn into headlines that say the moon causes earthquakes.”

Exactly when and where earthquakes strike is a random process, a scientific reality that often frustrates people who prefer patterns and having clues to warn before catastrophic events. The primary driving force behind earthquakes is the movement of tectonic plates.

In an interview in October, USGS research geophysicist Ken Hudnut explained why earthquakes are impossible to predict. To show how a fault gathers seismic stress that eventually ruptures into an earthquake, he showed a model of bricks sitting on sandpaper—equivalent to the two sides of the fault.

The bricks are attached to a rubber band connected to a handcrank, which, when it is moving, is like the accumulating seismic stress of plate tectonics. (In Southern California, the Pacific plate, where downtown L.A. sits, is moving northwest, while the North American plate is moving southeast.)

As Hudnut moved the handcrank, friction would keep the brick steady on the sandpaper, until at one point the accumulating force from the pulling rubber band was unbearable, and the brick would suddenly move—analogous to an earthquake. But when the movement happened wasn’t predictable. It was random.

There are other myths out there, such as the one in which hot, sunny “earthquake weather” somehow makes seismic events more likely; it doesn’t. Earthquakes happen underground, and the weather has no effect on their timing.

Hough said she decided to work on this study to rigorously test an idea that seismologists have long stated—that earthquakes aren’t more likely to happen on certain days of the calendar year or the cycle of the moon.

There are sometimes weird coincidences. For instance, in California, June 28 is the anniversary of a couple of memorable earthquakes: the magnitude 7.3 Landers earthquake that struck the Mojave Desert in 1992 (and the subsequent 6.5 Big Bear aftershock hours later); and the magnitude 5.6 Sierra Madre earthquake in 1991 that killed two people.

The next day, June 29, is the anniversary of the magnitude 6.8 Santa Barbara earthquake of 1925.

But those coincidences don’t mean anything.

“One analogy: if you had a classroom of 36 kids, on average, you’d expect to see three birthdays every month. You’d probably have a couple of kids on the exact same birthday,” Hough said, a result that does not hold some kind of larger meaning.

For her study, out of the more than 200 earthquakes she studied, if 20 or 30 of them happened on the full moon, “that would’ve actually been significant.” But that’s not what the results showed.

Note: The above post is reprinted from materials provided by Los Angeles Times, Distributed by Tribune Content Agency, LLC.

The Pentagon built with mineralized microbes predating dinosaurs

cross section of the ooids inside Rogenstein oolite
This is a cross section of the ooids inside Rogenstein oolite. Credit: ANU

A new study led by The Australian National University (ANU) has found that some of the building blocks of the Pentagon and Empire State Building were made by microbes that lived up to 340 million years ago, predating the dinosaurs.

The material, known as oolitic limestone, is a popular building material around the world and is almost completely made of millimetre-sized spheres of carbonate called ooids.

Co-researcher Dr Bob Burne from ANU said the new study found that ooids were made of concentric layers of mineralised microbes, debunking the popular ‘snowball theory’ that ooids were formed by grains rolling on the seafloor and accumulating layers of sediment.

“We have proposed a radically different explanation for the origin of ooids that explains their definitive features,” said

Dr Burne from the ANU Research School of Earth Sciences. “Our research has highlighted yet another vital role that microbes play on Earth and in our lives.”

Different types of oolitic limestones have formed in all geological periods and have been found around the world, including in the United States, the United Kingdom, Germany, the Bahamas, China and at Shark Bay in Western Australia.

Dr Burne said humans had known about and used oolitic limestone since ancient times.

“Many oolitic limestones form excellent building stones, because they are strong and lightweight,” he said.

“Mississippian oolite found in Indiana in the US has been used to build parts of the Pentagon in Virginia and parts of the Empire State Building in New York City.

“Jurassic oolite in England has been used to construct Buckingham Palace and much of the City of Bath, the British Museum and St Paul’s Cathedral.”

Professor Murray Batchelor from ANU led an international team of researchers on the study, which is published in Scientific Reports.

“Our mathematical model explains the concentric accumulation of layers, and predicts a limiting size of ooids,” said Professor Batchelor from the Research School of Physics and Engineering and the Mathematical Sciences Institute at ANU.

“We considered the problem theoretically using an approach inspired by a mathematical model developed in 1972 for the growth of some brain tumours.”

Professor Batchelor said the research findings could help better understand the effects of past climate change.

Reference:
Murray T. Batchelor, Robert V. Burne, Bruce I. Henry, Fei Li, Josef Paul. A biofilm and organomineralisation model for the growth and limiting size of ooids. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-017-18908-4

Note: The above post is reprinted from materials provided by Australian National University.

Fox Creek earthquakes linked to completion volume and location of hydraulic fracturing

A UAlberta researcher is the first to link the likelihood of earthquakes caused by hydraulic fracturing to the location of well pads and volume of liquid used in the process.
A UAlberta researcher is the first to link the likelihood of earthquakes caused by hydraulic fracturing to the location of well pads and volume of liquid used in the process.

The volume of hydraulic fracturing fluid and the location of well pads control the frequency and occurrence of measurable earthquakes, new Alberta Geological Survey and UAlberta research has found.

Ryan Schultz has been studying earthquakes in the Fox Creek, Alberta area since they started in December 2013. The seismologist — who works at the Alberta Geological Survey (a branch of the Alberta Energy Regulator) and with the University of Alberta — wanted to better understand what was causing the quakes.

Schultz and his colleagues found that when increased volumes were injected in susceptible locations (i.e., in connection with a nearby slip-ready fault), it transmits increased pressure to the fault line, leading to more numerous measurable earthquakes.

It’s not as simple as more volume equals more earthquakes, though-a link that scientists have long identified in the history of induced seismicity, dating back to the 1950s. There is another factor at play in the Fox Creek area, and it’s all about location, explained Schultz.

“If there is a pre-existing fault, but you’re not connected to it by some sort of fluid pathway, you can hydraulically fracture the formation, and you’re probably not going to cause a significant earthquake,” said Schultz. “It’s conceptually quite simple, but actually determining those things underground is really hard to do in practice.”

Since 2013, there has been a marked increase in the rate of earthquakes near Fox Creek, ranging up to magnitude 4s. While other research has pointed to industry activity as contributing to the quakes, this study is the first to identify specific factors causing the seismic activity.

Schultz said the next steps for the scientists are to build on these findings to better understand the geological factors occurring in this concentrated area of the Duvernay Formation with the future goal of better predicting best places to conduct hydraulic fracturing where it is least likely to cause these earthquakes.

To answer these questions, the UAlberta alumnus continues to work with Jeff Gu, geophysics professor in the Department of Physics and Schultz’s former graduate supervisor, and colleagues at the Alberta Geological Survey.

“We want to characterize everything we can about these earthquakes so that we can describe them in as much detail as possible,” said Schultz. “But when you answer questions, more questions come up.”

“Hydraulic fracturing volume is associated with induced earthquake productivity in the Duvernay play” will be published in the January 19 issue of Science, one of the world’s leading peer-reviewed scientific publications.

Reference:
R. Schultz, G. Atkinson, D. W. Eaton, Y. J. Gu, H. Kao. Hydraulic fracturing volume is associated with induced earthquake productivity in the Duvernay play. Science, 2018; 359 (6373): 304 DOI: 10.1126/science.aao0159

Note: The above post is reprinted from materials provided by University of Alberta.

World’s oldest known oxygen oasis discovered

Rock layers in the Pongola Basin, South Africa.
Rock layers in the Pongola Basin, South Africa.
Credit: Axel Hofmann/University of Johannesburg

In the Earth’s early history, several billion years ago, only traces of oxygen existed in the atmosphere and the oceans. Today’s air-breathing organisms could not have existed under those conditions. The change was caused by photosynthesizing bacteria, which created oxygen as a by-product — in vast amounts. 2.5-billion-year-old rock layers on several continents have yielded indications that the first big increase in the proportion of oxygen in the atmosphere took place then.

Now, working with international colleagues, Dr. Benjamin Eickmann and Professor Ronny Schönberg, isotope geochemists from the University of Tübingen have discovered layers in South Africa’s Pongola Basin which bear witness to oxygen production by bacteria as early as 2.97 billion years ago. That makes the Basin the earliest known home to oxygen-producing organisms — known as an oxygen oasis. The study has been published in the latest Nature Geoscience.

Conditions on Earth some three billion years ago were inhospitible to say the least. The atmosphere contained only one-one hundred thousandth of the oxygen it has today. The primeval oceans contained hardly any sulfate; but they did contain large amounts of ferrous iron. When bacteria started producing oxygen, it could initially bond with other elements, but began to enrich the atmosphere in a massive oxygen emission event around 2.5 billion years ago.

“We can see that in the disappearance of reduced minerals in the sediments on the continents. Certain sulfur signatures which can only be formed in a low-oxygen atmosphere are no longer to be found,” says Benjamin Eickmann, the study’s lead author. This event, which could be described as global environmental pollution, went down in the Earth’s history as the Great Oxygenation Event. It was a disaster for the early bacteria types which had evolved under low-oxygen conditions; the oxygen poisoned them. “However, after the first big rise, the atmosphere only contained 0.2 percent oxygen; today it’s around 21 percent,” Eickmann explains. Exposed to an atmosphere which contained increasing amounts of oxygen, the continents were subject to enhanced erosion. That led to more trace elements entering the oceans. The improved supply of nutrients in turn led to more life forms in the seas.

Sulfur signatures as an archive of Earth history

In their current study the researchers investigated the 2.97-bilion-year-old sediments deposited in the Pongola Basin in what is now South Africa. From the proportions of sulfur isotopes (particularly the of 34S/32S ratio), in the sediments, the researchers are able to conclude that the bacteria used the sulfate in the primeval seas as a source of energy, reducing it chemically.

“Sulfate is a form of oxidized sulfur. A higher concentration of sulfate in the water indicates that sufficient free oxygen must have been present in the shallow sea of the Pongola Basin,” Ronny Schönberg says. This free oxygen must have been produced by other, photosynthesizing bacteria. At the same time, another sulfur isotope signature (the 33S/32S ratio) in these sediments indicates a continued reduced, very low-oxygen atmosphere.

“That makes the Pongola Basin the oldest oxygen oasis known to date. The oxygen was building up in the water long before the Great Oxygenation Event, Schönberg explains. Several hundred million years later, the steadily rising levels of oxygen led to the oxidation of the atmosphere, and that is what made life on Earth — in all its variety as we know it today — even possible.

Reference:
Benjamin Eickmann, Axel Hofmann, Martin Wille, Thi Hao Bui, Boswell A. Wing, Ronny Schoenberg. Isotopic evidence for oxygenated Mesoarchaean shallow oceans. Nature Geoscience, 2018; DOI: 10.1038/s41561-017-0036-x

Note: The above post is reprinted from materials provided by Universitaet Tübingen.

New details emerge on temperature, mobility of earth’s lower crust in Rocky Mountains

This is Moho temperature at depths varying from 20 to 50 km.
This is Moho temperature at depths varying from 20 to 50 km. Credit: Colorado State University

Everything on the surface of the Earth rests on massive tectonic plates that resemble a jelly sandwich, with two rigid pieces — the upper crust and the upper mantle — enclosing a gooey middle layer of very hot rocks, which is the lower crust. The plates move ever so slowly around the globe over a deeper hot layer called the asthenosphere.

Temperature plays a fundamental role in determining the strength, thickness, and buoyancy of the lower crust. A research team led by Colorado State University has mapped the temperature and viscosity of the lower crust for the first time and found that, under much of the western United States, the layer is hot enough to be near its initial melting point and, therefore, quite runny.

This new research shows that significant regions of the lower crust have little strength, and that over several million years, could lead to many mountains in the western U.S. being flattened.

“Having a map of the temperature gives us an understanding of how strong the plate is,” said Derek Schutt, associate professor in CSU’s Department of Geosciences. “What we found is that there are places where the crust is not strong enough to hold the topography.”

Imagine three slices of Silly Putty, two frozen pieces lying on the top and bottom of one that is room temperature. When you push on the top layer, the warm Silly Putty will be squeezed flat. Similar mechanics are at work in the Earth’s crust.

“Mountains are formed by forces pushing things around, and weak areas collapsing,” according to Schutt.

Outside forces could potentially push on the crust and that force could be transferred deep inland, which is called orogenic float, he said. The new study suggests this process may occur more often than previously thought.

“That can cause mountains to form at a great distance from where you’re pushing on things,” Schutt said. “Because the lower crust is mobile, force can be transmitted over a large distance.”

Scientists generally think of tectonic plates, or lithosphere, as being made up of the crust and a cold uppermost mantle. But in this new analysis, the team saw something akin to ball bearings slipping between the crust and mantle. While not unexpected, this study was able to map the extent of the areas resembling ball bearings.

“The ‘ball bearings’ keep separate what’s happening in the mantle from what’s happening in the crust,” said Schutt.

Researchers calculated temperatures at the bottom of the crust, which varies in thickness, by measuring the velocity of seismic waves that travel near the interface between the lower crust and uppermost mantle.

In the western U.S., the crust is very hot, which is what makes it so weak.

“We know in general that the lower crust in the western United States seems hot,” said Schutt. “But this is the first time we’ve been able to really ascribe a temperature to a specific location.”

The findings, he said, are not too surprising. But the research could lead to more insight about why mountains exist and, more specifically, why they exist in places where the temperatures in the lower crust are so high.

Schutt and the research team will continue to explore the causes of variations in tectonic plate strength as part of an ongoing project between Colorado State University, Utah State University, and Scripps Institution of Oceanography at the University of California, San Diego. This research is funded by the National Science Foundation’s Earthscope Program.

Reference:
Derek L. Schutt, Anthony R. Lowry, Janine S. Buehler. Moho temperature and mobility of lower crust in the western United States. Geology, 2018; DOI: 10.1130/G39507.1

Note: The above post is reprinted from materials provided by Colorado State University.

‘Rainbow’ dinosaur had iridescent feathers like a hummingbird

Holotype fossil of Caihong juji, including line drawing of fossil skeleton.
This is holotype fossil of Caihong juji, including line drawing of fossil skeleton. Credit: Yu et al., 2018

Scientists discovered a dinosaur fossil with feathers so well-preserved that they were able to see the feathers’ microscopic color-bearing structures. By comparing the shapes of those feather structures with the structures in modern bird feathers, they’re able to infer that the new dino, Caihong juji (‘rainbow with the big crest’) had iridescent rainbow feathers like a hummingbird.

Birds are the last remaining dinosaurs. They’re also some of the most vibrantly colored animals on Earth. A new study in Nature Communications reveals that iridescent feathers go way back — a newly discovered species of dinosaur from 161 million years ago had rainbow coloring.

Caihong juji was tiny, about the size of a duck, with a bony crest on its head and long, ribbon-like feathers. And, based on analysis of its fossilized feathers, the feathers on its head, wings, and tail were probably iridescent, with colors that shimmered and shifted in the light. Its name reflects its appearance — in Mandarin, it means, “rainbow with the big crest.” The new species, which was first discovered by a farmer in northeastern China, was described by an international team of scientists led by Dongyu Hu, a professor in the College of Paleontology at the Shenyang Normal University in China.

“When you look at the fossil record, you normally only see hard parts like bone, but every once in a while, soft parts like feathers are preserved, and you get a glimpse into the past,” says Chad Eliason, a postdoctoral researcher at The Field Museum and one of the study’s authors. Eliason, who began work on the project as a postdoctoral fellow at the University of Texas at Austin, added, “The preservation of this dinosaur is incredible, we were really excited when we realized the level of detail we were able to see on the feathers.”

When the scientists examined the feathers under powerful microscopes, they could see the imprints of melanosomes, the parts of cells that contain pigment. For the most part, the pigment that was once present was long gone, but the physical structure of the melanosomes remained. As it turns out, that was enough for scientists to be able to tell what color the feathers were.

That’s because color isn’t only determined by pigment, but by the structure of the melanosomes containing that pigment. Differently shaped melanosomes reflect light in different colors. “Hummingbirds have bright, iridescent feathers, but if you took a hummingbird feather and smashed it into tiny pieces, you’d only see black dust. The pigment in the feathers is black, but the shapes of the melanosomes that produce that pigment are what make the colors in hummingbird feathers that we see,” explains Eliason.

The scientists were able to match the shapes of the pancake-shaped melanosomes in Caihong with the shapes of melanosomes in birds alive today. By finding birds with similarly shaped melanosomes, they were able to determine what kinds of colors Caihong may have flashed. The best matches: hummingbirds.

Colorful plumage is used in modern birds to attract mates — the rainbow feathers of Caihong might be a prehistoric version of a peacock’s iridescent tail. Caihong is the oldest known example of platelet-shaped melanosomes typically found in bright iridescent feathers.

It’s also the earliest known animal with asymmetrical feathers — a feature used by modern birds to steer when flying. Caihong couldn’t fly, though — its feathers were probably primarily used to attract mates and keep warm. While modern birds’ asymmetrical feathers are on their wingtips, Caihong’s were on its tail. “The tail feathers are asymmetrical but wing feathers not, a bizarre feature previously unknown among dinosaurs including birds,” said co-author Xing Xu of the Chinese Academy of Science. “This suggests that controlling [flight] might have been first evolved with tail feathers during some kind of aerial locomotion.”

But while Caihong’s feathers were a first, it had other traits associated with much earlier species of dinosaurs, including the bony crest on its head. “This combination of traits is rather unusual,” says co-author Julia Clarke of the University of Texas at Austin. “It has a velociraptor-type skull on the body of this very avian, fully feathered, fluffy kind of form.”

This combination of old and new traits, says Eliason, is evidence of mosaic evolution, the concept of different traits evolving independently from each other. “This discovery gives us insight into the tempo of how fast these features were evolving,” he adds.

For Eliason, the study also illuminates the value of big data. “To find the color of Caihong’s feathers, we compared its melanosomes with a growing database of thousands of measurements of melanosomes found in modern birds,” he says. It’s also broadened his own research interests.

“I came out of the project with a whole different set of questions that I wanted answers to — when I open up a drawer full of birds in the Field Museum’s collections, now I want to know when those iridescent feathers first developed, and how.”

Reference:
Dongyu Hu, Julia A. Clarke, Chad M. Eliason, Rui Qiu, Quanguo Li, Matthew D. Shawkey, Cuilin Zhao, Liliana D’Alba, Jinkai Jiang, Xing Xu. A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-017-02515-y

Note: The above post is reprinted from materials provided by Field Museum.

Digitally preserving important Arkansas dinosaur tracks

Dinosaur tracks.
Dinosaur tracks. Credit: Image courtesy of University of Arkansas, Fayetteville

Scientists using laser-imaging technology have documented and digitally preserved the first known set of theropod dinosaur tracks in the state of Arkansas.

The tracks, discovered in 2011 in a working gypsum quarry near Nashville, Ark., have since been destroyed. But high-resolution digital scans taken over a period of two weeks in 2011 allowed a team of researchers to study the tracks and determine that they were made by Acrocanthosaurus, a large, carnivorous dinosaur. The findings extended the known range of Acrocanthosaurus 56 miles east, to the western shore of an ancient inland sea.

“It actually confirms that the main genus of large theropods in North America was Acrocanthosaurus,” said Celina Suarez, an assistant professor in the Department of Geosciences who was part of the team that documented and studied the tracks. “It now has been found in Wyoming, Utah, Oklahoma, Arkansas and Maryland, a huge range.”

Results of the study were recently published in the journal PLOS ONE. Researchers also created a detailed, publicly accessible online map of the site and the tracks. Brian Platt, an assistant professor of geology from the University of Mississippi, led the study. Researchers from the University of Arkansas Center for Advanced Spatial Technology (CAST) provided the scanning equipment and expertise.

The Rush to Preserve the Site

After the tracks were discovered, researchers received a $10,000 Rapid Grant from the National Science Foundation to quickly document the site. The U of A’s vice provost for research and economic development and the J. William Fulbright College of Arts and Sciences provided matching grants, for a total of $30,000.

The mining company moved its operations to allow researchers a short window of time to document the find. Researchers used LiDAR, which stands for light detection and ranging, because traditional methods would have taken too long, said Suarez. “From a technical standpoint, it’s important that the ability to rapidly scan such a large area is available to paleontologists. It was invaluable for this project since we had such little time to work.”

The site had two different sized Acrocanthosaurus tracks, suggesting both adult and younger animals walked the ancient tidal flat about 100 million years ago, during the Cretaceous Period. It also contained tracks made by sauropods, long-necked plant-eating dinosaurs.

LiDAR uses a pulsed laser to measure distances to the earth in tiny increments, generating a data “point cloud” that is used to digitally recreate a physical space. In this case, the equipment was mounted on a lift over the site. By analyzing carbon and oxygen isotopes of the rock at the track surface, researchers determined that the track surface was indeed the surface that the animals stepped on, rather than an underlying layer that remained when the original surface eroded.

The digital reconstruction of the trackway site: http://trackways.cast.uark.edu/index.html

Reference:
Brian F. Platt, Celina A. Suarez, Stephen K. Boss, Malcolm Williamson, Jackson Cothren, Jo Ann C. Kvamme. LIDAR-based characterization and conservation of the first theropod dinosaur trackways from Arkansas, USA. PLOS ONE, 2018; 13 (1): e0190527 DOI: 10.1371/journal.pone.0190527

Note: The above post is reprinted from materials provided by University of Arkansas, Fayetteville.

Rates of great earthquakes not affected by moon phases, day of year

Seismogram
Seismogram being recorded by a seismograph at the Weston Observatory in Massachusetts, USA. Credit: Wikipedia

There is an enduring myth that large earthquakes tend to happen during certain phases of the Moon or at certain times during the year. But a new analysis published in Seismological Research Letters confirms that this bit of earthquake lore is incorrect.

After matching dates and lunar phases to 204 earthquakes of magnitude 8 or larger, Susan Hough of the U.S. Geological Survey concluded that there is no evidence that the rates of these great earthquakes are affected by the position of the Earth relative to either the Moon or the Sun.

In fact, the patterns that some observers see as linking large earthquakes with specific parts of the lunar cycle “are no different from the kinds of patterns you would get if the data are completely random,” Hough noted.

To determine this, Hough looked at both the day of the year and the lunar phase for 204 large earthquakes from the global earthquake catalog, dating back to the 1600s. To avoid detecting clusters of earthquakes within the data that are related to other factors, she chose to look at larger earthquakes because they are less likely to be an aftershock of a bigger earthquake.

Looking at only large earthquakes also allowed Hough to pare down the list to a manageable number that could be matched to lunar phase information found in online databases.

Her analysis did turn up some clusters of earthquakes on certain days, but to test for any significance in the patterns she was observing, she randomized the dates of the earthquakes to find out what kind of patterns would appear in these random data. The patterns in the random data were no different from the kinds of patterns showing up in the original data set, she found.

This isn’t an unusual finding, Hough noted. “When you have random data, you can get all sorts of apparent signals, just like when you flip a coin, you sometimes end up with five heads in a row.”

Hough did see some unusual “signals” in the original data; for instance, the highest number of earthquakes (16) occurring on a single day came seven days after the new moon. But this signal was not statistically significant, “and the lunar tides would be at a minimum at this point, so it doesn’t make any physical sense,” she noted.

Hough said that the Moon and Sun do cause solid Earth tidal stresses — ripples through the Earth itself, and not the waters hitting the coastline — and could be one of the stresses that contribute in a small way to earthquake nucleation.”

Some researchers have shown that “there is in some cases a weak effect, where there are more earthquakes when tidal stresses are high,” she said, “But if you read those papers, you’ll see that the authors are very careful. They never claim that the data can be used for prediction, because the modulation is always very small.”

The idea that the Sun and Moon’s positions in the sky can modulate earthquake rates has a long history, she said. “I’ve read Charles Richter’s files, the amateur predictors who wrote to him in droves, because he was the one person that people knew to write to … and if you read the letters, they’re similar to what people are saying now, it’s all the same ideas.”

“Sooner or later there is going to be another big earthquake on a full moon, and the lore will pop back up,” said Hough. “The hope is that this will give people a solid study to point to, to show that over time, there isn’t a track record of big earthquakes happening on a full moon.”

Note: The above post is reprinted from materials provided by Seismological Society of America.

World’s fifth largest diamond discovered in Lesotho

A diamond thought to be the fifth largest of gem quality ever found has been discovered in Lesotho
A diamond thought to be the fifth largest of gem quality ever found has been discovered in Lesotho, miner Gem Diamonds said. Credit: GEM DIAMONDS/AFP / HO

One of the world’s largest diamonds has been found in the Letseng mine in Lesotho, a small country surrounded by South Africa. The diamond was found by UK mining company Gem Diamonds and could be worth up to $40 million.

A diamond thought to be the fifth largest of gem quality ever found has been discovered in Lesotho, miner Gem Diamonds said Monday, and could be worth as much as $40 million.

The company unearthed the D-colour stone at the Letseng mine in the landlocked southern African country and described the 910-carat find as of “exceptional quality”.

“Since Gem Diamonds acquired Letseng in 2006, the mine has produced some of the world’s most remarkable diamonds, including the 603 carat Lesotho Promise,” Gem Diamonds chief executive Clifford Elphick said in a statement.

“However, this exceptional top quality diamond is the largest to be mined to date… This is a landmark discovery.”

Ben Davis, a mining analyst at Liberum Capital, speculated in a research note to investors that the diamond could be worth as much as $40 million (33 million euros).

Gem Diamonds shares in London were up 14 percent from the market open to £0.92 a piece.

Note: The above post is reprinted from materials provided by AFP.

Scientists have accidentally found the oldest ever butterfly or moth fossils

Butterfly
Credit: Shutterstock

Butterflies and moths, the Lepidoptera, are among the most beautiful of insects, familiar to almost everyone through thousands of different species from all around the world. But how they evolved has been something of a mystery to scientists because of a surprising lack of Lepidoptera fossils.

Now researchers in the Netherlands have discovered Lepidoptera fossils that are older than any previously found, proving these familiar insects have been around for at least 200m years. The particular type of fossils found mean we have to rethink Lepidoptera evolution. They imply that the long tube butterflies and moths use to suck nectar from flowers actually developed before flowering plants did, so it must have originally evolved for a different purpose.

The fossil record of ancient Lepidoptera is surprisingly meagre. Although butterflies may appear to be delicate creatures, their external skeletons are made of the same tough material, chitin, that all insects are made of. And chitin, or chitin decay products, preserve really very well in the fossil record.

In fact, some of the best ever fossils are of insects entombed in amber. Fossil Lepidoptera have been reported from a few exceptional deposits. For example, butterflies are known from the famous Florissant fossil beds of North America dating from the Eocene epoch, 34 million-years-old. A fossil caterpillar with the characteristic spinneret (the body part that produces silk) typical of all modern butterflies and moths has been reported from 125 million-year-old Lebanese amber. But until now, the fossil record went back no further.

This is especially odd because the Lepidoptera are closely related to another familiar modern group of insects, the caddis flies or Trichoptera. This group has an excellent fossil record extending back to the Permian period of the Palaeozoic era (250m years ago). As these groups share a common ancestor, the earliest Lepidoptera should, theoretically, also be found in the Permian period.

Lucky accident

The newly discovered fossils aren’t quite that old but they do date to the end of the Triassic period, the beginning of the age of dinosaurs. The delicate fossils bear the highly characteristic scales of butterflies and moths. They were discovered entirely by accident when researchers tried to extract pollen grains from rock samples from a borehole in north Germany to date the strata.

The process dissolves the rock (usually with the incredibly powerful hydrofluoric acid) to leave behind an organic residue that is rich in tough organic material. While this is usually pollen material and other so-called phytodebris from plants, it can include the remains of sclerotised (toughened) exoskeleton from insects and other invertebrates. Bits of fossil scorpions can be found this way for example.

Not many insects have scales on their wings, and those found on the wings of butterflies and moths are very different from those of other insects that do possess them. A characteristic feature of lepidopteran scales is a herring bone (V-shaped) pattern of fine lines in between larger ridges that extend along the scale. There are also characteristic outlines and margins that distinguish butterfly scales. So there is no doubt that the fossil scales found in the German borehole are those of ancient butterflies and moths.

Just as interesting, the scales are from a group of butterflies and moths known as the Glossata. Almost all of todays’ butterflies and moths belong to this group, characterised by the tube-shaped mouth part known as a “proboscis” used for feeding on fluids such as nectar. There are some primitive moths with mandibular (biting) mouth parts, and indeed some examples of these have been found from the Early Jurassic epoch (around 190 million-years-old). But the latest discoveries are even older, and push the origin of modern butterflies with proboscises back another 70 million years.

This forces a serious rethink for evolutionary biologists. Until now we’ve thought that the highly modified sucking mouthparts of modern butterflies and moths evolved as flowering plants diversified in the Early Cretaceous, around 100m years after the newly discovered fossils were created.

The researchers who discovered the fossils suggest that Lepidoptera may have first evolved their long proboscis tubes to suck up any available liquids at a time when their environment had become a lot drier. We know this kind of climate change did happen on the super continent of Pangaea in Triassic times, but it’s probably too early to tell if this theory is correct. If the fossil record can be pushed back 70m years in one stroke, it may get pushed back even further, and we’d need another way to explain the change.

Whatever the trigger for the development of the butterfly proboscis, it was clearly an evolutionary innovation that resulted in phenomenal diversity and added immensely to the beauty of planet Earth. Let us hope that many more of these serendipitous discoveries can shed even more light on the wonderful story of biological evolution. The key is in looking for fossils.

Note: The above post is reprinted from materials provided by David Martill, Professor of ​Palaeobiology, University of Portsmouth

This article was originally published on The Conversation. Read the original article.

Tiny dinosaur may have dazzled mates with rainbow ruff and a bony crest

Caihong juji is a newly described, bird-like dinosaur with an iridescent, rainbow crest.
Caihong juji is a newly described, bird-like dinosaur with an iridescent, rainbow crest. It lived in China about 161 million years ago, and may have used its impressive feathers to attract mates. Illustration by Velizar Simeonovski, The Field Museum, for UT Austin Jackson School of Geosciences. Credit: University of Texas at Austin

Ancient dinosaurs were adorned in some amazing ways, from the horns of the triceratops to the plates and spikes of the stegosaurus. A newly discovered, bird-like dinosaur fossil from China contains evidence that could add a new accessory to the list: a shaggy ruff of rainbow feathers.

A team of researchers, including scientists from The University of Texas at Austin, are the first to conduct an in-depth study of the dinosaur and describe it. They dubbed it Caihong juji—a name that means “rainbow with the big crest” in Mandarin—and think the dino used its flashy neck feathers and a bony crest on its snout to attract mates.

“Iridescent coloration is well known to be linked to sexual selection and signaling, and we report its earliest evidence in dinosaurs,” said Julia Clarke, a professor in the Department of Geological Sciences at the UT Jackson School of Geosciences who helped describe the new species. “The dinosaur may have a cute nickname in English, Rainbow, but it has serious scientific implications.”

A description of the exquisitely preserved, chicken-sized dinosaur was published on Jan. 15 in the journal Nature Communications. Dongyu Hu, a professor in the College of Paleontology at the Shenyang Normal University led the study.

Aside from making Jurassic ecosystems of 161 million years ago more colorful, the dinosaur is interesting because it has features that are both ancient and modern, said co-author Xing Xu, a professor at the Chines Academy of Sciences. The bony crest is a feature usually seen in dinosaurs from earlier eras, while its neck feathers show evidence of microscopic wide, flat, pigment-containing packages, or melanosomes, that may represent the first known occurrence of iridescence similar to that found in a variety of hummingbird species living today.

“There are crests associated with sexual selection previously known only in earlier dinosaurs, and yet there is also a bird mechanism of signaling or display appearing for the first time,” said Clarke, who helped lead the study with Hu and Xu.

Caihong is also the earliest known dinosaur with asymmetrical feathers, the feather type found on the wingtips of modern birds that helps control flight. But unlike birds today, Caihong’s asymmetrical feathers were on its tail, not its wings—a finding that suggests that early birds may have had a different steering or flight style.

“The tail feathers are asymmetrical but wing feathers are not, a bizarre feature previously unknown among dinosaurs including birds,” said Xu. “This suggests that controlling [flight] might have first evolved with tail feathers during some kind of aerial locomotion.”

The slab of rock from China’s Hebei Province where the dinosaur was discovered by a farmer in 2014 contained a nearly complete skeleton surrounded by impressions made by feathers. The impressions preserved the shape of the melanosomes. Researchers compared the melanosome impressions to melanosomes found in living birds and found that they most closely resembled those in the iridescent, rainbow feathers of hummingbirds.

Caihong is part of a group of small, bird-like dinosaurs that lived in China during the Jurassic, Xu said, but it stands out even among its closest relatives. While the other dinosaurs have bird-like, triangular skulls and long forearm bones in comparison to birds today, Caihong had a long and narrow skull, and unlike many of these other dinosaurs, its short forelimbs show proportions more akin to modern birds.

“This combination of traits is unusual,” Clarke said. “It has a rather velociraptor-looking low and long skull with this fully feathered, shaggy kind of plumage and a big fan tail. It is really cool… or maybe creepy looking depending on your perspective.”

The next step is figuring out what factors influenced Caihong to evolve such a distinctive look, rainbow feathers and all, said co-author Chad Eliason, a postdoctoral associate at the Field Museum of Natural History. He helped analyze the microstructural fossil evidence for color in the new specimen while he was a postdoctoral researcher at the UT Jackson School of Geosciences.

This combination of old and new traits, said Eliason, is evidence of mosaic evolution, the concept of different traits evolving independently from each other.

“This discovery gives us insight into the tempo of how fast these features were evolving,” he added.

Quanguo Li, a professor at the China University of Geosciences in Beijing and Matthew D. Shawkey, an associate professor at the University of Ghent in Belgium also participated in the study. The research was funded by the U.S. National Science Foundation and the National Science Foundation of China.

Note: The above post is reprinted from materials provided by University of Texas at Austin.

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