Why is Earth so biologically diverse? Mountains hold the answer

September 16, 2019

The volcano Chimborazo, Ecuador, that Alexander von Humboldt surveyed in 1802. Photo: Spyros Theodoridis/CMEC

What determines global patterns of biodiversity has been a puzzle for scientists since the days of von Humboldt, Darwin, and Wallace. Yet, despite two centuries of research, this question remains unanswered. The global pattern of mountain biodiversity, and the extraordinarily high richness in tropical mountains in particular, is documented in two companion Science review papers this week. The papers focus on the fact that the high level of biodiversity found on mountains is far beyond what would be expected from prevailing hypotheses.

“The challenge is that, although it is evident that much of the global variation in biodiversity is so clearly driven by the extraordinary richness of tropical mountain regions, it is this very richness that current biodiversity models, based on contemporary climate, cannot explain: mountains are simply too rich in species, and we are falling short of explaining global hotspots of biodiversity,” says Professor Carsten Rahbek, lead author of both review papers published in Science.

To confront the question of why mountains are so biologically diverse, scientists at the Center for Macroecology, Evolution and Climate (CMEC) at the GLOBE Institute of the University of Copenhagen work to synthesize understanding and data from the disparate fields of macroecology, evolutionary biology, earth sciences, and geology. The CMEC scientists are joined by individual collaborators from Oxford University, Kew Gardens, and University of Connecticut.

Part of the answer, these studies find, lies in understanding that the climate of rugged tropical mountain regions is fundamentally different in complexity and diversity compared to adjacent lowland regions. Uniquely heterogeneous mountain climates likely play a key role in generating and maintaining high diversity.

“People often think of mountain climates as bleak and harsh,” says study co-leader Michael K. Borregaard. “But the most species-rich mountain region in the world, the Northern Andes, captures, for example, roughly half of the world’s climate types in a relatively small region — much more than is captured in nearby Amazon, a region that is more than 12 times larger.”

Stressing another unique feature of mountain climate, Michael explains, “Tropical mountains, based in fertile and wet equatorial lowlands and extending into climatic conditions superficially similar to those found in the Arctic, span a gradient of annual mean temperatures over just a few km as large as that found over 10,000 km from the tropical lowlands at Equator to the arctic regions at the poles. It’s pretty amazing if you think about it.”

Another part of the explanation of the high biodiversity of certain mountains is linked to the geological dynamics of mountain building. These geological processes, interacting with complex climate changes through time, provide ample opportunities for evolutionary processes to act.

“The global pattern of biodiversity shows that mountain biodiversity exhibits a visible signature of past evolutionary processes. Mountains, with their uniquely complex environments and geology, have allowed the continued persistence of ancient species deeply rooted in the tree of life, as well as being cradles where new species have arisen at a much higher rate than in lowland areas, even in areas as amazingly biodiverse as the Amazonian rainforest,” says Professor Carsten Rahbek.

From ocean crust, volcanism and bedrock to mountain biodiversity

Another explanation of mountain richness, says the study, may lie in the interaction between geology and biology. The scientists report a novel and surprising finding: the high diversity is in most tropical mountains tightly linked to bedrock geology — especially mountain regions with obducted, ancient oceanic crust. To explain this relationship between geology and biodiversity, the scientists propose, as a working hypothesis, that mountains in the tropics with soil originating from oceanic bedrock provide exceptional environmental conditions that drive localized adaptive change in plants. Special adaptations that allow plants to tolerate these unusual soils, in turn, may drive speciation cascades (the speciation of one group leading to speciation in other groups), all the way to animals, and ultimately contribute to the shape of global patterns of biodiversity.

The legacy of von Humboldt — his 250th anniversary

The two papers are part of Science’s celebration of Alexander von Humboldt’s 250th birth anniversary. In 1799, Alexander von Humboldt set sail on a 5-year, 8000-km voyage of scientific discovery through Latin America. His journey through the Andes Mountains, captured by his famous vegetation zonation figure featuring Mount Chimborazo, canonized the place of mountains in understanding Earth’s biodiversity.

Acknowledging von Humboldt’s contribution to our understanding of the living world, Professor Carsten Rahbek, one of the founding scientists of the newly established interdisciplinary GLOBE Institute at the University of Copenhagen says:

“Our papers in Science are a testimony to the work of von Humboldt, which truly revolutionized our thinking about the processes that determine the distribution of life. Our work today stands on the shoulders of his work, done centuries ago, and follows his approach of integrating data and knowledge of different scientific disciplines into a more holistic understanding of the natural world. It is our small contribution of respect to the legacy of von Humboldt.”

References:

Carsten Rahbek, Michael K. Borregaard, Robert K. Colwell, Bo Dalsgaard, Ben G. Holt, Naia Morueta-Holme, David Nogues-Bravo, Robert J. Whittaker, Jon Fjelds&#2013265925;. Humboldt’s enigma: What causes global patterns of mountain biodiversity? Science, 2019 DOI: 10.1126/science.aax0149
Carsten Rahbek, Michael K. Borregaard, Alexandre Antonelli, Robert K. Colwell, Ben G. Holt, David Nogues-Bravo, Christian M. Ø. Rasmussen, Katherine Richardson, Minik T. Rosing, Robert J. Whittaker, Jon Fjeldså. Building mountain biodiversity: Geological and evolutionary processes. Science, 2019 DOI: 10.1126/science.aax0151

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

Pink Lake : What is Pink Lake? What causes Pink Lake in Australia?

September 14, 2019

What is pink lake?

Pink Lake is a salt lake in Western Australia’s Goldfields-Esperance region. Even if the lake’s waters were visibly pink historically, they were no rose since 2017 for over ten years. The concentration of salt in Pink Lake is essential to the pink color and, as conditions alter, Pink Lake could turn pink. It is located approximately 3 km (2 mi) south of Esperance, and the South Coast Highway binds eastwards.

It’s very complicated the dynamics of why a river turns rose. The pond color may be affected by external modifications and climate circumstances. The Pink Lake of Esperance has lost its blue color owing to modifications in the salinity resulting from human activities.

John Septimus Roe, a resident magister in Albany who contributed to the early formation of the colony of West Australia, named Spencer Waterway in 1848 after Sir Richard Spencer. Lake Warden, next door, is reported to be named after Lady Ann Warden Spencer, Sir Richard Spencer’s spouse.

The Lake in the past had a distinct pink hue and was colloquially referred to as Pink Lake until 1966 when the Shire president, Cr W S Paterson, submitted a successful request to the Committee on Geographic Names, which resulted in Lake Spencer becoming officially a Pink Lake. The Pink Lake has been a tourist attraction for many years in the Esperance region, with its surroundings, its arteries and the local companies.

Historically, Pink Lake was the terminal lake in the Lake Warden wetland scheme, where water from the main lake suite (Wheatfield, Woody and Windabout) and Lake Warden would pour periodically into Pink Lake, adding salts to the atmosphere.

Increasing salt concentrations coupled with reducing evaporation water levels during the summer cause the appearance of purple hue that can be seen throughout the nation in ponds. With the building of the railway line and South Coast Highway, Pink Lake lost its link to Lake Warden and the southern lakes.

Commercial salt mining, which started in 1896 and stopped lowering salt concentrations in the lake in 2007. Due to drying in the catchment area connected with neighboring estates, further decreases in the salt concentration of the lake are created by freshwater reaching the scheme through a mixture of surface water inflow and enhanced groundwater inflow.

Where Pink Lake?

Location: Goldfields-Esperance, Western Australia
Basin countries‎: ‎Australia
Area: 99 ha
Max. width‎: ‎2 km (1 mi)
Max. length‎: ‎4 km (2 mi)

What causes Pink Lake in Australia?

Due to the green alga Dunaliella salina, halobacterium Halobacteria cutirubrum and/or elevated quantity of brine prawn, the unique color of the water modifications. Once the lake water hits a amount of salinity higher than sea water, the temperature is sufficiently elevated and sufficient light requirements are supplied, the alga starts to produce the red pigment beta carotene. The purple halobacterium grows at the bottom of the lake in the salt crust.

Scientists discovered that pink water bodies such as Lake Hillier contain both halobacteria and a sort of algae called Dunaliella salina that thrives in cold settings such as pink rivers. The red carotenoid pigments that Halobacteria and d have secreted. Salina is accountable for the otherworldly colours of the purple waters. In the Dead Sea, too, these same algae thrive.

Building a highway and a railway line is thought to have changed the flow of water into the lake, decreasing its salinity, which is why it no longer looks purple (as of 2017).

When Pink Lake is Pink?

A pink lake is a red or rose-colored lake. This is often triggered by the existence of algae, such as Dunaliella salina, which generates carotenoids. Due to modifications in natural water stream, decreased evaporation, and salt production, the distinctive color has disappeared — a practice that finished in 2007. But now, in a venture thought to be an Australian first, a group of researchers will explore how to restore the lake to its blue glory.

Is the Pink Lake toxic?

The pink water isn’t toxic

Can you swim in Pink Lake Australia?

In fact, swimming in the water of the lake is safe and fun, but for normal tourists it is impossible to do it as the lake can not be visited.

Is there any other Pink Lakes?

Yes. Australia is fortunate enough to have a lot of these natural wonders.

In the distant south of Victoria, a collection of salt lakes in the hot weather transform a beautiful deep pink.

Lakes Crosbie, Becking, Kenyon and Hardy are famous tourist sights in Murray Sunset National Park.

Pink Lake close Dimboola is of special significance to the individuals of Wotjobaluk and the salt is collected by side and marketed there.

Lake Tyrrell, close to Sea Lake, is the biggest salt lake in Victoria and draws tourists from all over the globe as a star-watching place.

There are several purple lakes in Western Australia. The most well-known are Lake Hillier close Esperance and Hutt Lagoon in the midwest of the state.

Every year, Hutt Lagoon draws hundreds of visitors and has become famous with Chinese travelers in particular as touring the lake has become a status symbol in China.

How many Pink Lake in Australia?

There are over 10 pink lakes in Australia, There are four rose beaches in Victoria’s Murray-Sunset National Park, Lake Crosbie, Lake Becking, Lake Kenyon and Lake Hardy, as well as a purple inlet in Western Australia, called Hutt Lagoon, between Geraldton and Kalbarri.

Where to find Emerald Crystals in the United States?

September 7, 2019

What is Emerald?

Emerald is a gemstone and a range of green-colored mineral beryl (Be3Al2(SiO3)6) by trace quantities of chromium and sometimes vanadium. On Mohs scale, Beryl has a durability of 7.5–8. Included are the most emeralds, so their toughness (crash resistance) is usually considered poor. The emerald is cyclosilicates. Emerald is an emerald.

The term “emerald” is obtained from Vulgar Latin (via Old French: esmeraude and Middle English: emeraude): esmaralda / esmaraldus, a version of Latin smaragdus which emerged in Ancient Greek (smaragdos).

Emeralds, like all colored gemstones, are graded using four fundamental parameters–the four Cs of knowledge: colour, clarity, cut and weight of the carat. Normally, color is the most significant factor in the grading of colored gemstones. However, transparency is regarded to be a near second in the grading of emeralds. A good emerald must have as outlined below not only a sheer green hue, but also a large degree of transparency to be regarded a top gem.

Emerald’s Color

Color is split into three parts in gemology: hue, saturation, and tone. Emeralds are present in hues varying from yellow-green to blue-green, the main hue being green. The standard secondary hues observed in emeralds are yellow and blue. Emeralds are regarded only gems that are medium to light in color; light-tone gems are regarded as green beryl instead.

On a scale where 0 percent color is colorless and 100 percent opaque white, the best emeralds are about 75 percent color. Moreover, it will saturate a good emerald and have a bright (vivid) colour. Gray is the ordinary modifier of saturation or mask discovered in emeralds; a dull-green hue is a grayish-green hue.

Emerald in the United States

North Carolina and South Carolina

In the United States very few emeralds were mined. Since the late 1800s, North Carolina was a sporadic producer of small amounts of emeralds from a few mines.

Tiffany and Company and a number of landowners operated the Crabtree Emerald mine from 1894 to the 1990s. Many fine, transparent emeralds have been developed and tonnes, slabbed and cabochon cutting, of smart pegmatitis have been marketed as a “emerald matrix.”

In a white matrix of glass and feldspath the cabochons had jade and tourmaline prisms. This page displays a sample of the Crabtree Pegmatite.

North American

A tiny mine close Hiddenite, North America Emerald Mines works in North Carolina. Between 1995 and 2010, the Houston Museum of Natural Science manufactured over 20,000 carats of emeraldean, including six inch length 1.869-carat crystal valuable at $3.5 million.

On the same premises a crushed stone quarry is run by employees watching for hydrothermal vein signs and bags that contain emeralds at times. It is one of the world’s only precious mines that sells rural rock.

A new duck-billed dinosaur, Kamuysaurus japonicus, identified

September 7, 2019

A reconstruction of Kamuysaurus japonicus. Credit: Kobayashi Y., et al, Scientific Reports, September 5, 2019

The dinosaur, whose nearly complete skeleton was unearthed from 72 million year old marine deposits in Mukawa Town in northern Japan, belongs to a new genus and species of a herbivorous hadrosaurid dinosaur, according to the study published in Scientific Reports. The scientists named the dinosaur Kamuysaurus japonicus.

A partial tail of the dinosaur was first discovered in the outer shelf deposits of the Upper Cretaceous Hakobuchi Formation in the Hobetsu district of Mukawa Town, Hokkaido, in 2013. Ensuing excavations found a nearly complete skeleton that is the largest dinosaur skeleton ever found in Japan. It’s been known as “Mukawaryu,” nicknamed after the excavation site.

In the current study, a group of researchers led by Professor Yoshitsugu Kobayashi of the Hokkaido University Museum conducted comparative and phylogenetic analyses on 350 bones and 70 taxa of hadrosaurids, which led to the discovery that the dinosaur belongs to the Edmontosaurini clade, and is closely related to Kerberosaurus unearthed in Russia and Laiyangosaurus found in China.

The research team also found that Kamuysaurus japonicus, or the deity of Japanese dinosaurs, has three unique characteristics that are not shared by other dinosaurs in the Edmontosaurini clade: the low position of the cranial bone notch, the short ascending process of the jaw bone, and the anterior inclination of the neural spines of the sixth to twelfth dorsal vertebrae.

According to the team’s histological study, the dinosaur was an adult aged 9 or older, measured 8 meters long and weighed 4 tons or 5.3 tons (depending on whether it was walking on two or four legs respectively) when it was alive. The frontal bone, a part of its skull, has a big articular facet connecting to the nasal bone, suggesting the dinosaur may have had a crest. The crest, if it existed, is believed to resemble the thin, flat crest of Brachylophosaurus subadults, whose fossils have been unearthed in North America.

The study also shed light on the origin of the Edmontosaurini clade and how it might have migrated. Its latest common ancestors spread widely across Asia and North America, which were connected by what is now Alaska, allowing them to travel between the two continents. Among them, the clade of Kamuysaurus, Kerberosaurus and Laiyangosaurus inhabited the Far East during the Campanian, the fifth of six ages of the Late Cretaceous epoch, before evolving independently.

The research team’s analyses pointed to the possibility that ancestors of hadrosaurids and its subfamilies, Hadrosaurinae and Lambeosaurinae, preferred to inhabit areas near the ocean, suggesting the coastline environment was an important factor in the diversification of the hadrosaurids in its early evolution, especially in North America.

Reference:
Yoshitsugu Kobayashi, Tomohiro Nishimura, Ryuji Takasaki, Kentaro Chiba, Anthony R. Fiorillo, Kohei Tanaka, Tsogtbaatar Chinzorig, Tamaki Sato & Kazuhiko Sakurai. A new Hadrosaurine (Dinosauria: Hadrosauridae) from the Marine Deposits of the Late cretaceous Hakobuchi formation Yezo Group, Japan. Scientific Reportsvolume, 2019 DOI: 10.1038/s41598-019-48607-1

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

Role of earthquake motions in triggering a ‘surprise’ tsunami

September 7, 2019

Visualization of the modelled coupled earthquake and tsunami across Palu Bay, from Ulrich et al., 2019: Left: Seismic waves being generated while the earthquake propagates southward in a ‘superfast’ manner. Warm colours denote higher movements across the geological faults and higher ground shaking (snapshot after 15 seconds of earthquake simulation time). Right: The movements of the earthquake beneath the bathtub shaped Palu Bay generate a ‘surprise’ tsunami (snapshot of the water waves aftee 20s of simulation time of the tsunami scenario). Image credit: LMU.

In newly published research, an international team of geologists, geophysicists, and mathematicians show how coupled computer models can accurately recreate the conditions leading to the world’s deadliest natural disasters of 2018, the Palu earthquake and tsunami, which struck western Sulawesi, Indonesia in September last year. The team’s work was published in Pure and Applied Geophysics.

The tsunami was as surprising to scientists as it was devastating to communities in Sulawesi. It occurred near an active plate boundary, where earthquakes are common. Surprisingly, the earthquake caused a major tsunami, although it primarily offset the ground horizontally — normally, large-scale tsunamis are typically caused by vertical motions.

Researchers were at a loss — what happened? How was the water displaced to create this tsunami: by landslides, faulting, or both? Satellite data of the surface rupture suggests relatively straight, smooth faults, but do not cover areas offshore, such as the critical Palu Bay. Researchers wondered — what is the shape of the faults beneath Palu Bay and is this important for generating the tsunami? This earthquake was extremely fast. Could rupture speed have amplified the tsunami?

Using a supercomputer operated by the Leibniz Supercomputing Centre, a member of the Gauss Centre for Supercomputing, the team showed that the earthquake-induced movement of the seafloor beneath Palu Bay itself could have generated the tsunami, meaning the contribution of landslides is not required to explain the tsunami’s main features. The team suggests an extremely fast rupture on a straight, tilted fault within the bay. In their model, slip is mostly lateral, but also downward along the fault, resulting in anywhere from 0.8 metres to 2.8 metres vertical seafloor change that averaged 1.5 metres across the area studied. Critical to generating this tsunami source are the tilted fault geometry and the combination of lateral and extensional strains exerted on the region by complex tectonics.

The scientists come to this conclusion using a cutting-edge, physics-based earthquake-tsunami model. The earthquake model, based on earthquake physics, differs from conventional data-driven earthquake models, which fit observations with high accuracy at the cost of potential incompatibility with real-world physics. It instead incorporates models of the complex physical processes occurring at and off of the fault, allowing researchers to produce a realistic scenario compatible both with earthquake physics and regional tectonics.

The researchers evaluated the earthquake-tsunami scenario against multiple available datasets. Sustained supershear rupture velocity, or when the earthquake front moves faster than the seismic waves near the slipping faults, is required to match simulation to observations. The modeled tsunami wave amplitudes match the available wave measurements and the modeled inundation elevation (defined as the sum of the ground elevation and the maximum water height) qualitatively match field observations. This approach offers a rapid, physics-based evaluation of the earthquake-tsunami interactions during this puzzling sequence of events.

“Finding that earthquake displacements probably played a critical role generating the Palu tsunami is as surprising as the very fast movements during the earthquake itself,” said Thomas Ulrich, PhD student at Ludwig Maximilian University of Munich and lead author of the paper. “We hope that our study will launch a much closer look on the tectonic settings and earthquake physics potentially favouring localized tsunamis in similar fault systems worldwide.”

Reference:
T. Ulrich, S. Vater, E. H. Madden, J. Behrens, Y. van Dinther, I. van Zelst, E. J. Fielding, C. Liang, A.-A. Gabriel. Coupled, Physics-Based Modeling Reveals Earthquake Displacements are Critical to the 2018 Palu, Sulawesi Tsunami. Pure and Applied Geophysics, 2019; DOI: 10.1007/s00024-019-02290-5

Note: The above post is reprinted from materials provided by Gauss Centre for Supercomputing.

Deep-sea sediments reveal solar system chaos: An advance in dating geologic archives

September 7, 2019

Research vessel JOIDES Resolution off the coast of Hawaii. Credit: International Ocean Discovery Program.

A day is the time for Earth to make one complete rotation on its axis, a year is the time for Earth to make one revolution around the Sun — reminders that basic units of time and periods on Earth are intimately linked to our planet’s motion in space relative to the Sun. In fact, we mostly live our lives to the rhythm of these astronomical cycles.

The same goes for climate cycles. The cycles in daily and annual sunlight cause the familiar diel swings in temperature and the seasons. On geologic time scales (thousands to millions of years), variations in Earth’s orbit are the pacemaker of the ice ages (so-called Milankovitch cycles). Changes in orbital parameters include eccentricity (the deviation from a perfect circular orbit), which can be identified in geological archives, just like a fingerprint.

The dating of geologic archives has been revolutionized by the development of a so-called astronomical time scale, a “calendar” of the past providing ages of geologic periods based on astronomy. For example, cycles in mineralogy or chemistry of geologic archives can be matched to cycles of an astronomical solution (calculated astronomical parameters in the past from computing the planetary orbits backward in time). The astronomical solution has a built-in clock and so provides an accurate chronology for the geologic record.

However, geologists and astronomers have struggled to extend the astronomical time scale further back than about fifty million years due to a major roadblock: solar system chaos, which makes the system unpredictable beyond a certain point.

In a new study published in the journal Science, Richard Zeebe from the University of Hawai’i at Manoa and Lucas Lourens from Utrecht University now offer a way to overcome the roadblock. The team used geologic records from deep-sea drill cores to constrain the astronomical solution and, in turn, used the astronomical solution to extend the astronomical time scale by about 8 million years. Further application of their new method promises to reach further back in time still, one step and geologic record at a time.

On the one hand, Zeebe and Lourens analyzed sediment data from drill cores in the South Atlantic Ocean across the late Paleocene and early Eocene, ca. 58-53 million years ago (Ma). The sediment cycles displayed a remarkable expression of one particular Milankovitch parameter, Earth’s orbital eccentricity. On the other hand, Zeebe and Lourens computed a new astronomical solution (dubbed ZB18a), which showed exceptional agreement with the data from the South Atlantic drill core.

“This was truly stunning,” Zeebe said. “We had this one curve based on data from over 50-million-year-old sediment drilled from the ocean floor and then the other curve entirely based on physics and numerical integration of the solar system. So the two curves were derived entirely independently, yet they looked almost like identical twins.”

Zeebe and Lourens are not the first to discover such agreement — the breakthrough is that their time window is older than 50 Ma, where astronomical solutions disagree. They tested 18 different published solutions but ZB18a gives the best match with the data.

The implications of their work reach much further. Using their new chronology, they provide a new age for the Paleocene-Eocene boundary (56.01 Ma) with a small margin of error (0.1%). They also show that the onset of a large ancient climate event, the Paleocene-Eocene Thermal Maximum (PETM), occurred near an eccentricity maximum, which suggests an orbital trigger for the event. The PETM is considered the best paleo-analog for the present and future anthropogenic carbon release, yet the PETM’s trigger has been widely debated. The orbital configurations then and now are very different though, suggesting that impacts from orbital parameters in the future will likely be smaller than 56 million years ago.

Zeebe cautioned, however, “None of this will directly mitigate future warming, so there is no reason to downplay anthropogenic carbon emissions and climate change.”

Regarding implications for astronomy, the new study shows unmistakable fingerprints of solar system chaos around 50 Ma. The team found a change in frequencies related to Earth’s and Mars’ orbits, affecting their amplitude modulation (often called a “beat” in music).

“You can hear amplitude modulation when tuning a guitar. When two notes are nearly the same, you essentially hear one frequency, but the amplitude varies slowly — that’s a beat,” Zeebe explained. In non-chaotic systems, the frequencies and beats are constant over time, but they can change and switch in chaotic systems (called resonance transition). Zeebe added, “The change in beats is a clear expression of chaos, which makes the system fascinating but also more complex. Ironically, the change in beats is also precisely what helps us to identify the solution and extend the astronomical time scale.”

Reference:
Richard E. Zeebe, Lucas J. Lourens. Solar System chaos and the Paleocene–Eocene boundary age constrained by geology and astronomy. Science, 2019; 365 (6456): 926 DOI: 10.1126/science.aax0612

Note: The above post is reprinted from materials provided by University of Hawaii at Manoa. Original written by Marcie Grabowski.

Earth’s fingerprint hints at finding habitable planets beyond the solar system

September 7, 2019

Earth's mantle (dark red) lies below the crust (brown layer near the surface) and above the outer core (bright red). — Earth’s mantle (dark red) lies below the crust (brown layer near the surface) and above the outer core (bright red). Credit: CC image by Argonne National Laboratory via Flickr

Two McGill University astronomers have assembled a “fingerprint” for Earth, which could be used to identify a planet beyond our Solar System capable of supporting life.

McGill Physics student Evelyn Macdonald and her supervisor Prof. Nicolas Cowan used over a decade of observations of Earth’s atmosphere taken by the SCISAT satellite to construct a transit spectrum of Earth, a sort of fingerprint for Earth’s atmosphere in infrared light, which shows the presence of key molecules in the search for habitable worlds. This includes the simultaneous presence of ozone and methane, which scientists expect to see only when there is an organic source of these compounds on the planet. Such a detection is called a “biosignature.”

“A handful of researchers have tried to simulate Earth’s transit spectrum, but this is the first empirical infrared transit spectrum of Earth,” says Prof. Cowan. “This is what alien astronomers would see if they observed a transit of Earth.”

The findings, published Aug. 28 in the journal Monthly Notices of the Royal Astronomical Society, could help scientists determine what kind of signal to look for in their quest to find Earth-like exoplanets (planets orbiting a star other than our Sun). Developed by the Canadian Space Agency, SCISAT was created to help scientists understand the depletion of Earth’s ozone layer by studying particles in the atmosphere as sunlight passes through it. In general, astronomers can tell what molecules are found in a planet’s atmosphere by looking at how starlight changes as it shines through the atmosphere. Instruments must wait for a planet to pass — or transit — over the star to make this observation. With sensitive enough telescopes, astronomers could potentially identify molecules such as carbon dioxide, oxygen or water vapour that might indicate if a planet is habitable or even inhabited.

Cowan was explaining transit spectroscopy of exoplanets at a group lunch meeting at the McGill Space Institute (MSI) when Prof. Yi Huang, an atmospheric scientist and fellow member of the MSI, noted that the technique was similar to solar occultation studies of Earth’s atmosphere, as done by SCISAT.

Since the first discovery of an exoplanet in the 1990s, astronomers have confirmed the existence of 4,000 exoplanets. The holy grail in this relatively new field of astronomy is to find planets that could potentially host life — an Earth 2.0.

A very promising system that might hold such planets, called TRAPPIST-1, will be a target for the upcoming James Webb Space Telescope, set to launch in 2021. Macdonald and Cowan built a simulated signal of what an Earth-like planet’s atmosphere would look like through the eyes of this future telescope which is a collaboration between NASA, the Canadian Space Agency and the European Space Agency.

The TRAPPIST-1 system located 40 light years away contains seven planets, three or four of which are in the so-called “habitable zone” where liquid water could exist. The McGill astronomers say this system might be a promising place to search for a signal similar to their Earth fingerprint since the planets are orbiting an M-dwarf star, a type of star which is smaller and colder than our Sun.

“TRAPPIST-1 is a nearby red dwarf star, which makes its planets excellent targets for transit spectroscopy. This is because the star is much smaller than the Sun, so its planets are relatively easy to observe,” explains Macdonald. “Also, these planets orbit close to the star, so they transit every few days. Of course, even if one of the planets harbours life, we don’t expect its atmosphere to be identical to Earth’s since the star is so different from the Sun.”

According to their analysis, Macdonald and Cowan affirm that the Webb Telescope will be sensitive enough to detect carbon dioxide and water vapour using its instruments. It may even be able to detect the biosignature of methane and ozone if enough time is spent observing the target planet.

Prof. Cowan and his colleagues at the Montreal-based Institute for Research on Exoplanets are hoping to be some of the first to detect signs of life beyond our home planet. The fingerprint of Earth assembled by Macdonald for her senior undergraduate thesis could tell other astronomers what to look for in this search. She will be starting her Ph.D. in the field of exoplanets at the University of Toronto in the Fall.

Reference:
Evelyn J R Macdonald, Nicolas B Cowan. An empirical infrared transit spectrum of Earth: opacity windows and biosignatures. Monthly Notices of the Royal Astronomical Society, 2019; 489 (1): 196 DOI: 10.1093/mnras/stz2047

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

Crack in Pacific seafloor caused volcanic chain to go dormant

September 7, 2019

Volcano: UH geologists have discovered 10 million years of silence in a chain of volcanoes between Northeast Asia and Russia. — UH geologists have discovered 10 million years of silence in a chain of volcanoes between Northeast Asia and Russia.

From his geology lab at the University of Houston, Jonny Wu has discovered that a chain of volcanoes stretching between Northeast Asia and Russia began a period of silence 50 million years ago, which lasted for 10 million years. In the journal Geology, Wu, assistant professor of structural geology, tectonics and mantle structure, is reporting that one of the most significant plate tectonic shifts in the Pacific Ocean forced the volcanoes into dormancy.

At the end of the Cretaceous Period, shortly after dinosaurs disappeared, the Pacific Plate, the largest tectonic plate on Earth, mysteriously changed direction. One possible result was the formation of a prominent bend in the Hawaiian Islands chain, and another, just discovered by Wu, was the volcanic dormancy along a 900-mile stretch between Japan and the remote Sikhote-Alin mountain range in Russia in what is known as the Pacific Ring of Fire, where many volcanoes form.

“Around the time of the volcano dormancy, a crack in the Pacific Ocean Plate subducted, or went below, the volcanic margin. The thin, jagged crack in the seafloor was formed by plates moving in opposing directions and when they subduct, they tend to affect volcanic chains,” reports Wu.

When the volcanoes revived 10 million years later, the radiogenic isotopes within the magma were noticeably different.

“The productivity of magma within the once-violent chain of volcanoes was only one-third its previous level,” said Wu, who has linked this phenomenon to the subduction of the Pacific-Izanagi mid-ocean ridge, an underwater mountain.

Scientists have long understood that volcanic activity above subduction zones, where one tectonic plate converges towards and dives beneath another, is driven by water brought deep within the Earth by the diving subducting plate. When the water reaches depths of around 65 miles, it causes the solid mantle to partially melt and produces magma that may rise and feed volcanoes.

“However, in the case of the East Asian volcanoes, subduction of the immense seafloor crack interrupted its water-laden conveyor belt into the deep Earth. As a result, the volcanoes turned off,” said Wu.

Wu and UH doctoral student Jeremy Tsung-Jui Wu, who is not related to Jonny Wu, discovered the dormancy — and the reason for it — after examining a magmatic catalog of 900 igneous rock radio-isotopic values from the Cretaceous to Miocene eras. They also found evidence that the crack in the Pacific Plate was about 50% shorter than originally believed.

Reference:
Jeremy Tsung-Jui Wu, Jonny Wu. Izanagi-Pacific ridge subduction revealed by a 56 to 46 Ma magmatic gap along the northeast Asian margin. Geology, 2019; DOI: 10.1130/G46778.1

Note: The above post is reprinted from materials provided by University of Houston. Original written by Laurie Fickman.

Kīlauea lava fuels phytoplankton bloom off Hawai’i Island

September 7, 2019

Kīlauea lava entry on the southeast coastline of Hawai'i Island as seen from UH research vessel Kaimikai o Kanaloa. Credit: Ryan Tabata, UH. — Kīlauea lava entry on the southeast coastline of Hawai’i Island as seen from UH research vessel Kaimikai o Kanaloa. Credit: Ryan Tabata, UH.

When Kīlauea Volcano erupted in 2018, it injected millions of cubic feet of molten lava into the nutrient-poor waters off the Big Island of Hawai’i. The lava-impacted seawater contained high concentrations of nutrients that stimulated phytoplankton growth, resulting in an extensive plume of microbes that was detectable by satellite.

A study led by researchers at the University of Hawai’i (UH) at Mānoa and University of Southern California (USC) and published today in the journal Science revealed that this biological response hinged on unexpectedly high concentrations of nitrate, despite the negligible amount of nitrogen in basaltic lava. The research team determined that nitrate was brought to the surface ocean when heat from the substantial input of lava into the ocean warmed nutrient-rich deep waters and caused them to rise up, supplying the sunlit layer with nutrients.

After observing the phytoplankton bloom in satellite images, the UH Mānoa Center for Microbial Oceanography: Research and Education (C-MORE) organized a rapid response oceanographic expedition on UH research vessel Ka’imikai-O-Kanaloa from July 13 to 17, 2018—in the thick of Kilauea’s activity. The team conducted round-the-clock operations in the vicinity of the lava entry region to test water chemistry and the biological response to the dramatic event.

Co-lead authors Sam Wilson at C-MORE and Nick Hawco, a USC researcher who will be joining the UH Mānoa Oceanography Department in January 2020, tested the hypothesis that lava and volcanic dust would stimulate microorganisms that are limited by phosphate or iron, which are chemicals found in lava.

As it turned out, since there was so much lava in the water, the dissolved iron and phosphate combined into particles, making those nutrients unavailable for microbes. Further, deep, heated seawater became buoyant and brought up nitrate which caused other classes of phytoplankton to bloom.

It is possible that this mechanism has led to similar ocean fertilization events in the past associated with the formation of the Hawaiian Islands and other significant volcanic eruptions, the authors suggest. Depending on their location, sustained eruption on this scale could also facilitate a large flux of nitrate from the deep ocean and perturb larger scale ocean circulation, biology and chemistry.

“The expedition in July 2018 provided a unique opportunity to see first-hand how a massive input of external nutrients alters marine ecosystems that are finely attuned to low-nutrient conditions,” said Wilson. “Ecosystem responses to such a substantial addition of nutrients are rarely observed or sampled in real time. UH has a strong tradition of not only volcanic research, but also looking at its impacts on the surrounding environment such as the ocean, groundwater, atmosphere. This latest piece of research improves our understanding of lava-seawater interactions within the much broader context of land-ocean connections.”

“Science is a team sport,” said Dave Karl, senior author and co-director of the UH Mānoa Simons Collaboration on Ocean Processes and Ecology (SCOPE). “SCOPE emphasizes collaboration, where scientists with complementary skills came together to complete this unique, interdisciplinary project.”

In the future, the team hopes to sample the newly-formed ponds at the bottom of the Halema’uma’u crater and further investigate lava-seawater interactions in the laboratory.

Reference:
S.T. Wilson el al., “Kīlauea lava fuels phytoplankton bloom in the North Pacific Ocean,” Science (2019). science.sciencemag.org/lookup/ … 1126/science.aax4767

H. Ducklow el al., “Volcano-stimulated marine photosynthesis,” Science (2019). science.sciencemag.org/cgi/doi … 1126/science.aay8088

Note: The above post is reprinted from materials provided by University of Hawaii at Manoa.

Scientists Confirm The Discovery of a Mineral Never Before Seen in Nature

September 5, 2019

Wedderburn meteorite

Scientists have discovered a new mineral, one never before seen in nature, lodged inside a meteorite found near Wedderburn in central Victoria.

They believe that the mineral was probably forged in an ancient planet’s molten core, long since destroyed.

The meteorite from its million-year-plus journey is red and black and deeply scarred, and certainly looks like the part. Edscottite has been christened the mineral it includes.

After close examination of the Wedderburn Meteorite, a lemon-sized chunk of metal found just outside Wedderburn in 1951, the mineral was found and is now part of the collection of Museums Victoria.

It was discovered in a distant Australian gold rush city on the side of a highway. Wedderburn was a hotspot for prospectors in the ancient days–it’s still ##lies–but no one ever saw a nugget like this.

The Wedderburn meteorite, discovered in 1951 just north-east of the city, was a tiny 210-gram piece of strange-looking space rock falling from the heavens. Scientists have tried to decipher their secrets for centuries, and researchers have just decoded another.

Scientists analyzed the Wedderburn meteorite and checked the first natural appearance of what they call’ edscottite’ in a fresh research conducted by Caltech mineralogist Chi Ma: a unusual type of iron-carbide mineral that has never been discovered in existence.

Since the spatial origins of the Wedderburn meteorite were first identified, numerous research teams have examined the distinctive black-and-red rock–to the extent that only about one-third of the original specimen remains intact, held in Australia’s Museums Victoria Geological Collection.

In a sequence of pieces, the remainder were removed to analyze what the meteorite is made of. These analyzes disclosed gold and iron traces along with rarer minerals such as kamacite, schreibersite, taenite, and troilite. Now edscottite can be added to that list.

The finding of edscottite–named in honor of the University of Hawaii’s meteorite specialist and cosmochemist Edward Scott–is important because we have never before verified that this separate nuclear formulation of iron carbide mineral happens naturally.

Such a confirmation is important as it is a prerequisite for the International Mineralogical Association (IMA) to formally recognize minerals as such.

For centuries, a synthesized form of the mineral iron carbide has been considered –a stage generated during metal smelting.

But thanks to Chi Ma and UCLA’s new analysis of geophysicist Alan Rubin, edscottite is now an official member of the mineral club of the IMA, which is more exclusive than you might believe.

“We found 500,000 to 600,000 minerals in the laboratory, but less than 6,000 that nature itself did,” Museums Victoria senior geoscience curator Stuart Mills, who was not involved in the new study, told The Age.

As for how this sliver of natural edscottite ended up just outside rural Wedderburn can’t be known for sure, but according to planetary scientist Geoffrey Bonning from Australian National University, who wasn’t engaged in the research, the mineral could have developed in an ancestral planet’s warm, pressurized heart.

Bonning informed The Age that this ill-fated, edscottite-producing planet might have endured some sort of huge cosmic crash–involving another planet, or a moon, or an object–and was torn apart, with the fractured pieces of this demolished globe flowing through moment and space.

Millions of years ago, thought continues, one such piece lands just outside Wedderburn by opportunity–and for it, our knowledge of the Universe is the richest.

Reference:
Edscottite, Fe5C2, a new iron carbide mineral from the Ni-rich Wedderburn IAB iron meteorite. DOI: 10.2138/am-2019-7102

T. rex had an air conditioner in its head

September 4, 2019

A graphic thermal image of a T. rex with its dorsotemporal fenestra glowing on the skull. Illustration courtesy of Brian Engh.

Tyrannosaurus rex, one of the largest meat-eating dinosaurs on the planet, had an air conditioner in its head, suggest scientists from the University of Missouri, Ohio University and University of Florida, while challenging over a century of previous beliefs.

In the past, scientists believed two large holes in the roof of a T. rex’s skull — called the dorsotemporal fenestra — were filled with muscles that assist with jaw movements.

But that assertion puzzled Casey Holliday, a professor of anatomy in the MU School of Medicine and lead researcher on the study.

“It’s really weird for a muscle to come up from the jaw, make a 90-degree turn, and go along the roof of the skull,” Holliday said. “Yet, we now have a lot of compelling evidence for blood vessels in this area, based on our work with alligators and other reptiles.”

Using thermal imaging — devices that translate heat into visible light — researchers examined alligators at the St. Augustine Alligator Farm Zoological Park in Florida. They believe their evidence offers a new theory and insight into the anatomy of a T. rex’s head.

“An alligator’s body heat depends on its environment,” said Kent Vliet, coordinator of laboratories at the University of Florida’s Department of Biology. “Therefore, we noticed when it was cooler and the alligators are trying to warm up, our thermal imaging showed big hot spots in these holes in the roof of their skull, indicating a rise in temperature. Yet, later in the day when it’s warmer, the holes appear dark, like they were turned off to keep cool. This is consistent with prior evidence that alligators have a cross-current circulatory system — or an internal thermostat, so to speak.”

Holliday and his team took their thermal imaging data and examined fossilized remains of dinosaurs and crocodiles to see how this hole in the skull changed over time.

“We know that, similarly to the T. rex, alligators have holes on the roof of their skulls, and they are filled with blood vessels,” said Larry Witmer, professor of anatomy at Ohio University’s Heritage College of Osteopathic Medicine. “Yet, for over 100 years we’ve been putting muscles into a similar space with dinosaurs. By using some anatomy and physiology of current animals, we can show that we can overturn those early hypotheses about the anatomy of this part of the T. rex’s skull.”

Reference:
Casey M. Holliday, William Ruger Porter, Kent A. Vliet, Lawrence M. Witmer. The Frontoparietal Fossa and Dorsotemporal Fenestra of Archosaurs and Their Significance for Interpretations of Vascular and Muscular Anatomy in Dinosaurs. The Anatomical Record, 2019; DOI: 10.1002/ar.24218

Note: The above post is reprinted from materials provided by University of Missouri-Columbia.

What drives plate tectonics?

September 4, 2019

Global paleomagnetic plate reconstructions a. 270 Ma, b. 180 Ma, and inset the Present Tethyan Realm. Credit: ©Science China Press

Plate tectonics was founded in the late 1960s, and it concerns the distribution and movements of plates, the uppermost layer of the Earth. Plate movements not only control the distributions of earthquakes, volcanoes, and mineral resources in the crust, but also affect the ocean and atmospheric circulations above the crust. Therefore, plate tectonics has been regarded as the fundamental unifying paradigm for understanding the history of Earth.

Despite the widely accepted kinematics of plate tectonics, the driving force of plate tectonics is still one of the most challenging problems since the birth of this theory. The subduction of oceanic slabs is considered the dominant driving force based on observations of Cenozoic subduction systems along the circum-Pacific region. However, the difficulty in observing the oceanic subduction slabs beneath collisional orogens hampers the ability to quantitatively evaluate the role of subducting oceanic slabs. Alternative driving forces such as ridge push, continental slab-pull, plume upwelling and large-scale mantle convection have been proposed at different subduction-collision belts along the Tethyan Realm (Fig 1), the largest continental collisional zone. The Tethyan evolution can be summarized as the process by which many continental fragments were ruptured sequentially from Gondwana and then drift towards Laurasia/Eurasia.

Scientists from the State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences in Beijing found “switches” between continental rupture, continental collision, and oceanic subduction initiation in the Tethyan evolution after a reappraisal of geological records from the surface and new global-scale geophysical images at depth. They proposed that the “switches” were all controlled by oceanic subductions. All oceanic Tethyan slabs acted in a way that transferred the Gondwana-detached continents in the south into the terminal in the north, so they depicted the scenario as a “Tethyan one-way train” (Figure. 2a and b). The engine of the “train” was the negative buoyancy of the subducting oceanic slabs. The results also shed light on supercontinent assembly and breakup cycles. Subductions not only assemble the supercontinent but also effectively break-up the supercontinent.

The new results will not close the discussions on driving force of plate tectonics, but future Tethyan research may test the new proposal and improve the understanding of how plate tectonics works.

Reference:
Bo Wan et al, Cyclical one-way continental rupture-drift in the Tethyan evolution: Subduction-driven plate tectonics, Science China Earth Sciences (2019). DOI: 10.1007/s11430-019-9393-4

Note: The above post is reprinted from materials provided by Science China Press.

Understanding the link between fracking and earthquakes

September 4, 2019

Hydraulic fracturing (Creative Commons photo)

Researchers studying hydraulic fracturing have answered a longstanding question over how the practice can sometimes cause moderate earthquakes and may be able to use their model to forecast when quakes linked to fracking might occur.

The team of seismologists and geophysicists from Dalhousie University and the University of Calgary conducted a new study aimed at understanding the physical mechanisms of earthquakes “induced” by hydraulic fracturing, a widely used method to stimulate extraction of hydrocarbons from the ground.

They wanted to understand why these events were occurring, in spite of laboratory measurements suggesting they shouldn’t happen in the type of shale rock undergoing stimulation.

What they found is that the injection of fracturing fluids can lead to a slow slip on a fault. That can gradually put enough strain on another, distant section of the fault to cause it to slip suddenly and produce an earthquake.

Possibilities for new monitoring and mitigation strategies

Dmitry Garagash, a professor in the Civil and Resource Engineering Department at Dalhousie, co-authored the study that was published in Science Advances, a top-tier online journal of the American Association for the Advancement of Science.

“Work like this allows us to understand the phenomenon better and may ultimately lead to improved regulations and practices of hydraulic fracturing,” said Dr. Garagash.

“The developed physics-based model of fault slip in response to changes caused by fracking can lead to better prediction of this type of events, but also suggest new field monitoring and mitigation strategies.”

The team was led by Dr. Thomas Eyre, a postdoctoral researcher in the Department of Geoscience at the University of Calgary, and looked at so-called “felt events” or earthquakes that are large enough to be felt in nearby communities.

That included a magnitude 4.2 earthquake earlier this year near Red Deer, Alta., and a 4.5 quake last year near Fort St. John, B.C.

The researchers analyzed a set of seismic and geological data, some of which were collected during a magnitude 4.1 hydraulic fracturing-induced earthquake on Jan. 12, 2016, near Fox Creek in northwest Alberta.

An important milestone

Hydraulic fracturing involves pumping a mixture of water, sand and chemicals into a well bore under high pressure to create fractures in reservoir rocks to exploit them for oil and gas.

“This is an important new milestone for understanding earthquakes caused by hydraulic fracturing,” says study co-author Dr. David Eaton, a professor in the University of Calgary’s Department of Geoscience.

Dr. Eyre said that based on the research team’s model, corroborated by field observations and by physics-based mathematical modeling, the earthquake initiates on a distant part of the fault where friction conditions are unstable.

“In the case we studied, the earthquake occurred hundreds of meters above the hydraulic fracturing zone,” Dr. Eyre said.

Previous studies have suggested that fault slip in shale formations targeted by fracking occurs too slowly to produce an earthquake. But the new research found that this slow slip can alter the conditions on the fault a distance away from the site of fracking and cause a distant quake.

Reference:
Thomas S. Eyre et al. The role of aseismic slip in hydraulic fracturing–induced seismicity, Science Advances (2019). DOI: 10.1126/sciadv.aav7172

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

Ancient animal species: Fossils dating back 550 million years among first animal trails

September 4, 2019

A fossilized trail of the animal Yilingia spiciformis, dating back 550 million years. The trail was found in China by a team of scientists including Shuhai Xiao of the Virginia Tech College of Science. Credit: Virginia Tech College of Science

In a remarkable evolutionary discovery, a team of scientists co-led by a Virginia Tech geoscientist has discovered what could be among the first trails made by animals on the surface of the Earth roughly a half-billion years ago.

Shuhai Xiao, a professor of geosciences with the Virginia Tech College of Science, calls the unearthed fossils, including the bodies and trails left by an ancient animal species, the most convincing sign of ancient animal mobility, dating back about 550 million years. Named Yilingia spiciformis—that translates to spiky Yiling bug, Yiling being the Chinese city near the discovery site—the animal was found in multiple layers of rock by Xiao and Zhe Chen, Chuanming Zhou, and Xunlai Yuan from the Chinese Academy of Sciences’ Nanjing Institute of Geology and Palaeontology.

The findings are published in the latest issue of Nature. The trials are from the same rock unit and are roughly the same age as bug-like footprints found by Xiao and his team in a series of digs from 2013 to 2018 in the Yangtze Gorges area of southern China, and date back to the Ediacaran Period, well before the age of dinosaurs or even the Pangea supercontinent. What sets this find apart: The preserved fossil of the animal that made the trail versus the unknowable guesswork where the body has not been preserved.

“This discovery shows that segmented and mobile animals evolved by 550 million years ago,” Xiao said. “Mobility made it possible for animals to make an unmistakable footprint on Earth, both literally and metaphorically. Those are the kind of features you find in a group of animals called bilaterans. This group includes us humans and most animals. Animals and particularly humans are movers and shakers on Earth. Their ability to shape the face of the planet is ultimately tied to the origin of animal motility.”

The animal was a millipede-like creature a quarter-inch to an inch wide and up to 4 inches long that alternately dragged its body across the muddy ocean floor and rested along the way, leaving trails as loing as 23 inches. The animal was an elongated narrow creature, with 50 or so body segments, a left and right side, a back and belly, and a head and a tail.

The origin of bilaterally symmetric animals—known as bilaterians—with segmented bodies and directional mobility is a monumental event in early animal evolution, and is estimated to have occurred the Ediacaran Period, between 635 and 539 million years ago. But until this finding by Xiao and his team, there was no convincing fossil evidence to substantiate those estimates. One of the recovered specimens is particularly vital because the animal and the trail it produced just before its death are preserved together.

Remarkably, the find also marks what may be the first sign of decision making among animals—the trails suggest an effort to move toward or away from something, perhaps under the direction of a sophisticated central nerve system, Xiao said. The mobility of animals led to environmental and ecological impacts on the Earth surface system and ultimately led to the Cambrian substrate and agronomic revolutions, he said.

“We are the most impactful animal on Earth,” added Xiao, also an affiliated member of the Global Change Center at Virginia Tech. “We make a huge footprint, not only from locomotion, but in many other and more impactful activities related to our ability to move. When and how animal locomotion evolved defines an important geological and evolutionary context of anthropogenic impact on the surface of the Earth.”

Rachel Wood, a professor in the School of GeoSciences at University of Edinburgh in Scotland, who was not involved with the study, said, “This is a remarkable finding of highly significant fossils. We now have evidence that segmented animals were present and had gained an ability to move across the sea floor before the Cambrian, and more notably we can tie the actual trace-maker to the trace. Such preservation is unusual and provides considerable insight into a major step in the evolution of animals.”

Reference:
Death march of a segmented and trilobate bilaterian elucidates early animal evolution, Nature (2019). DOI: 10.1038/s41586-019-1522-7

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

A new reptile species from Wales named by Bristol student

September 4, 2019

The type specimen of Aenigmaspina pantyfynnonensis, photograph and 3D scan model, produced by Erin Patrick as part of her Masters thesis work in Bristol. This little block, the size of the palm of your hand, shows the backbone, curved round from top right to bottom left, and in the middle the ribs and shoulder blades. Scale bar is 1 cm. Credit: University of Bristol

After resting for decades in the storerooms of the Natural History Museum in London, a fragmentary fossil from the Late Triassic (200 million years ago) has been named as a new species by a Masters’ student at the University of Bristol.

Erin Patrick studied this creature for her MSc Palaeobiology dissertation research under the supervision of Professor Mike Benton and Dr. David Whiteside from Bristol’s School of Earth Sciences.

The fossil is one of several novel species named from Pant-y-ffynnon Quarry in Wales. It was found in the 1950s but has been ignored since then because it was so tiny and hard to study.

Most of the specimen is in two blocks of rock that fit together to form a lump that would sit on a child’s hand. On the surface are small bones, but it revealed its treasures when it was scanned. While no skull is present, these blocks contain a number of vertebrae, ribs, one scapula, and tiny armor plates from its back.

Using CT scanning, these tiny bones (some mere millimeters wide and long) could be studied in three-dimensional detail, allowing Erin to examine fossils otherwise hidden in the rock.

When she first saw the scans, Erin commented: “I was amazed. The rock and small fossils looked like nothing in particular, but the scans showed up fantastic detail. I worked on the images at ten times magnification to see all the minute features.”

When the fossil was found, its discoverers dubbed it “Edgar,” but as a new species it has now been given the formal name Aenigmaspina pantyffynnonensis.

The first part of the name refers to its enigmatic spine table, a feature of the vertebrae that supported the armor plates on the back. The second part of the name refers to Pant-y-ffynnon quarry in South Wales where it was found.

Erin added: “While creating the 3-D models, I was looking for anatomical features that would say what this new beast was.

“We could see it wasn’t a dinosaur, and the spine tables and armor plates put it on the crocodile side of the evolutionary tree.

“During the Triassic, there was a flurry of different reptile groups emerging related to modern crocodiles, but most of these were pretty huge and had special features not present in Aenigmaspina.”

Professor Benton said: “We were able to code Aenigmaspina for 100 or so characters and calculate its most likely position in the tree of life, but the answers were not 100 percent certain. It seems to be a relative of another little armored beast called Erpetosuchus known from the Late Triassic of north-east Scotland and the eastern United States.”

Dr. Whiteside said: “Erin’s work has added important knowledge to our understanding of Late Triassic faunas worldwide and particularly to the animals present in South Wales during that time.

“We know that Aenigmaspina lived on a small limestone island, part of a sub-tropical archipelago and this brings the number of major new species described from Pant-y-ffynnon quarry to four, two of which have been named by Bristol Masters students.”

Reference:
Erin L. Patrick et al. A new crurotarsan archosaur from the Late Triassic of South Wales, Journal of Vertebrate Paleontology (2019). DOI: 10.1080/02724634.2019.1645147

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

Earthquake study casts doubt on early warnings but hints at improved forecasting

September 4, 2019

Map of seismic sensors (green triangles) around the epicenter (red star) of one of the earthquakes near the city of Tsukuba, Ibaraki Prefecture. Credit: 2019 Satoshi Ide

A recent study has investigated around 100,000 localized seismic events to search for patterns in the data. University of Tokyo Professor Satoshi Ide discovered that earthquakes of differing magnitudes have more in common than was previously thought. This suggests development of early warning systems may be more difficult than hoped. But conversely, similarities between some events indicate that predictable characteristics may aid researchers attempting to forecast seismic events.

Since the 1980s, seismologists have wondered how feasible it might be to predict how an earthquake will behave given some information about its initial conditions—in particular, whether the eventual magnitude could be determined based on seismic measurements near the epicenter. Most researchers consider this idea improbable, given the randomness of earthquake behavior, but Ide thinks there’s more to it than that.

“Taking inspiration from a study comparing different-sized earthquakes, I decided to analyze a seismic dataset from a region known as the Tohoku-Hokkaido subduction zone in eastern Japan,” said Ide. “A systematic comparison of around 100,000 seismic events over 15 years leads me to believe earthquakes are not different in random ways but share many similarities.”

To draw comparisons between earthquakes, Ide first selected the larger examples from the dataset with magnitudes greater than 4.5. He also selected smaller earthquakes in the same regions as these larger ones. Ide then ascertained mathematically how similar seismic signals were between pairs of large and small earthquakes. He used a statistical function for the comparison of signals called a cross-correlation on data from 10 seismic stations close to the pairs of earthquakes in each case.

“Some pairs of large and small earthquakes start with exactly the same shaking characteristics, so we cannot tell the magnitude of an earthquake from initial seismic observations,” explained Ide. “This is bad news for earthquake early warning. However, for future forecasting attempts, given this symmetry between earthquakes of different magnitudes, it is good to know they are not completely random.”

The study is published in Nature.

Reference:
Frequent observations of identical onsets of large and small earthquakes, Nature (2019). DOI: 10.1038/s41586-019-1508-5

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

Analyzing the world’s oldest woody plant fossil

August 31, 2019

A, photograph of Armoricaphyton chateaupannense preserved in 2D as carbonaceous thin films. B, SEM image of a transverse section of an axis of a specimen of A. chateaupannense preserved in 3D showing the radially aligned tracheids. Credit: Canadian Light Source

Mapping the evolution of life on Earth requires a detailed understanding of the fossil record, and scientists are using synchrotron-based technologies to look back—way, way back—at the cell structure and chemistry of the earliest known woody plant.

Dr. Christine Strullu-Derrien and colleagues used the Canadian Light Source’s SM beamline at the University of Saskatchewan to study Armoricaphyton chateaupannense, an extinct woody plant that is about 400 million years old. Their research focused on lignin, an organic compound in the plant tracheids, elongated cells that help transport water and mineral salts. Lignin makes the cells walls rigid and less water permeable, thereby improving the conductivity of their vascular system.

Strullu-Derrien, a scientific associate at the Natural History Museum in London, England and the Natural History Museum in Paris, France, had described A. chateaupannense some years ago and returned to it for this project.

“Studies have been done previously on Devonian plants but they were not woody,” she said. “A. chateaupannense is the earliest known woody plant and it’s preserved in both 2-D form as flat carbonaceous films and 3-D organo-mineral structures. This allows for comparison to be done between the two types of preservation,” she said.

Although the fossils used in the study were collected in the Armorican Massif, a geologically significant region of hills and flatlands in western France, Strullu-Derrien said early Devonian woody plants have also been found in New Brunswick and the Gaspé area in Quebec “although these are 10 million years younger than the French one.”

One of the challenges in this kind of study is that the fossilization process modifies soft plant tissue, which alters or obscures its original biochemical structure and makes it difficult to precisely reconstruct the original chemistry. This study, however, aided by advanced visualization technologies, identified lignified cells in the fossils, suggesting the plant contained decay-resistant lignin compounds.

“Analyses show that both the 2-D and 3-D fossils have the same chemical composition, which is different than modern lignin, but the chemical signal of lignin is not completely lost in the fossilization process,” she said. Although the type of preservation of the plant fossils is not unique, “the combination of synchrotron methods used to study the structure and the chemistry of the wood at this level of detail is novel.”

The results of the research are in a paper entitled “On the Structure and Chemistry of Fossils of the Earliest Woody Plant,” published by Palaeontology.

Given how ubiquitous and important wood is as a structural component of modern plants, Strullu-Derrien’s investigation advances the knowledge around when and how wood first evolved. Yet, questions remain: “Wood first appears in small plants but did it have a different function than it does today in trees, for example?” posed Strullu-Derrien.

To find an answer, she will apply the same techniques used in this study on plants of other geological ages “to follow the evolution of their structure and to be able to find when, or in what condition of preservation, the remaining organic matter has kept a chemical signal of lignin.”

“Our study illustrates the capabilities of synchrotrons to investigate the early evolution of tissue systems in plants. It’s crucial to have access to these techniques to reach the level of resolution needed for getting chemical signals such as lignin. This represents a developing and promising area for the study of fossils that will complement the morpho-anatomical data and help to interpret the structures,” she said.

Reference:
Christine Strullu‐Derrien et al. On the structure and chemistry of fossils of the earliest woody plant, Palaeontology (2019). DOI: 10.1111/pala.12440

Note: The above post is reprinted from materials provided by Canadian Light Source.

Fossil colour studies are changing our idea of how dinosaurs looked

August 31, 2019

In-depth fossil analysis could help us understand the true functions of colour. Credit: Aline Dassel/Pixabay, licensed under Pixabay licence

What colour were the dinosaurs? If you have a picture in your head, fresh studies suggest you may need to revise it. New fossil research also suggests that pigment-producing structures go beyond how the dinosaurs looked and may have played a fundamental role inside their bodies too.

The latest findings have also paved the way for a more accurate reconstruction of the internal anatomy of extinct animals, and insight into the origins of features such as feathers and flight.

Much of this stems from investigations into melanin, a pigment found in structures called melanosomes inside cells that gives external features including hair, feather, skin and eyes their colour—and which, it now turns out, is abundant inside animals’ bodies too.

“We’ve found it in places where we didn’t think it existed,” said Dr. Maria McNamara, a palaeobiologist at University College Cork in Ireland. “We’ve found melanosomes in lungs, the heart, liver, spleen, connective tissues, kidneys… They’re pretty much everywhere.”

The discoveries in her team’s newest research, published in mid-August, were made using advanced microscopy and synchrotron X-ray techniques, which harness the energy of fast-moving electrons to help examine fossils in minute detail.

Using these, the researchers found that melanin was widespread in the internal organs of both modern and fossil amphibians, reptiles, birds and mammals—following up a finding they made last year that melanosomes in the body of existing and fossil frogs in fact vastly outnumbered those found externally.

What’s more, they were surprised to discover that the chemical make-up and shape of the melanosomes varied between organ types—thus opening up exciting opportunities to use them to map the soft tissues of ancient animals.

Secondary

These studies also have further implications. For one, the finding that melanosomes are so common inside animals’ bodies may overhaul our very understanding of melanin’s function, says Dr. McNamara. “There’s the potential that melanin didn’t evolve for colour at all,” she said. “That role may actually be secondary to much more important physiological functions.”

Her research indicates that it may have an important role in homeostasis, or regulation of the internal chemical and physical state of the body, and the balance of its metallic elements.

“A big question now is does this apply to the first, most primitive vertebrates?” said Dr. McNamara. “Can we find fossil evidence of this? Which function of melanin is evolutionarily primitive—production of colour or homeostasis?”

At the same time, the findings imply that we may need to review our understanding of the colours of ancient animals. That’s because fossil melanosomes previously assumed to represent external hues may in fact be from internal tissues, especially if the fossil has been disturbed over time.

Dr. McNamara says her research has also shown that melanosomes can change shape and shrink over the course of millions of years, potentially affecting colour reconstructions.

Further complicating the picture is that animals contain additional non-melanin pigments such as carotenoids and what is known as structural colour, which was only recently identified in fossils. In 2016, a study by Dr. McNamara’s team on the skin of a 10-million-year-old snake found that these could be preserved in certain mineralised remains.

“These have the potential to preserve all aspects of the colour-producing gamut that vertebrates have,” said Dr. McNamara.

She hopes over time that these findings and techniques will together help us to much more accurately interpret the colours of ancient organisms—though in these early days, she doesn’t have examples of animals for which this has already changed.

Deep time

Many of the significant strides in this area have come out of a project that Dr. McNamara leads called ANICOLEVO, which set out to look into the evolution of colour in animals over deep time—or hundreds of millions of years.

The project’s starting point was that previous animal colour studies largely omitted in-depth fossil analysis, leaving a significant gap by basing what we know about colour mainly on modern organisms.

But it has since led to even wider investigation. Dr. McNamara says it is providing fresh hints on the kinds of biological structures and processes that are essential for survival in terrestrial and aquatic environments. “It looks like we’ll be able to look into much broader, exciting questions about what it means to be an animal,” she said.

Part of her research on two fossils found in China even showed that flying reptiles known as pterosaurs had feathers, potentially taking the evolution of these structures back a further 80 million years to 250 million years ago. The fossils contained preserved melanosomes with diverse shapes and sizes, one of the tell-tale signs of feathers.

“We were able to show for the first time that not only were dinosaurs feathered, but an entirely different group of animals, the pterosaurs, also had feathers,” said Dr. McNamara.

Another project she worked on, called FOSSIL COLOUR, compared the chemistry of colour patterns between fossil and modern insects. Again, says Dr. McNamara, these don’t entirely map onto each other.

“It’s already clear that the fossilisation process has altered the chemistry somewhat, so we’re doing experiments to try to understand these changes.”

What’s evident is that there’s lots still to find out about colour. “We’re just at the tip of the iceberg when it comes to fossil colour research,” said Dr. McNamara.

Thermoregulation

Other researchers agree that there’s more to animal colour than meets the eye. Dr. Matthew Shawkey, an evolutionary biologist at Ghent University in Belgium, said that looking into properties and functions beyond colour’s use for visual means like signalling and camouflage will be critical to understanding its true significance.

“For example, how do colours affect thermoregulation? Flight? Such functions may be complementary to, or even more significant, than purely visual functions,” he said.

Dr. Shawkey is looking into such questions, with one of his recent studies indicating that the wing colour of birds may play an important role in flight efficiency by leading to different rates of heating.

“What started as a novelty of deciphering dinosaur colours has turned into a very serious field which is studying the origins of key pigment systems, how the evolution of colourful structures may have helped drive major evolutionary transitions like the origin of flight, and how colour is related to ecology and sexual selection,” said Dr. Steve Brusatte, a vertebrate palaeontologist and evolutionary biologist at the University of Edinburgh, UK.

Ultimately, we may be able to find out more about colour than once thought possible. “When I was growing up, so many of the dinosaur books I read in school said that we would never know what colour they were,” said Dr. Brusatte. “But as is so often the case in science, it was silly to treat this as impossible.”

He said he is excited to see what comes next, with the field just in its infancy: “Palaeontologists now have a whole new window into understanding the biology and evolution of long-extinct organisms.”

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

Ancient die-off greater than the dinosaur extinction

August 31, 2019

This photograph shows rocks from the Belcher Islands in Hudson Bay, Canada, from which doctoral candidate Malcolm Hodgskiss collected barite samples dating 2.02 to 1.87 billion years old. Credit: Malcolm Hodgskiss

Clues from Canadian rocks formed billions of year ago reveal a previously unknown loss of life even greater than that of the mass extinction of the dinosaurs 65 million years ago, when Earth lost nearly three-quarters of its plant and animal species.

Rather than prowling animals, this die-off involved miniscule microorganisms that shaped the Earth’s atmosphere and ultimately paved the way for those larger animals to thrive.

“This shows that even when biology on Earth is comprised entirely of microbes, you can still have what could be considered an enormous die-off event that otherwise is not recorded in the fossil record,” said Malcolm Hodgskiss, co-lead author of a new study published in Proceedings of the National Academy of Sciences.

Invisible clues

Because this time period preceded complex life, researchers cannot simply dig up fossils to learn what was living 2 billion years ago. Even clues left behind in mud and rocks can be difficult to uncover and analyze.

Instead, the group turned to barite, a mineral collected from the Belcher Islands in Hudson Bay, Canada, that encapsulates a record of oxygen in the atmosphere. Those samples revealed that Earth experienced huge changes to its biosphere — the part of the planet occupied by living organisms — ending with an enormous drop in life approximately 2.05 billion years ago that may also be linked to declining oxygen levels.

“The fact that this geochemical signature was preserved was very surprising,” Hodgskiss said. “What was especially unusual about these barites is that they clearly had a complex history.”

Looking at the Earth’s productivity through ancient history provides a glimpse into how life is likely to behave over its entire existence — in addition to informing observations of atmospheres on planets outside our solar system.

“The size of the biosphere through geologic time has always been one of our biggest questions in studying the history of the Earth,” said Erik Sperling, an assistant professor of geological sciences at Stanford who was not involved with the study. “This new proxy demonstrates how interlinked the biosphere and levels of oxygen and carbon dioxide in the atmosphere are.”

Biological angle

This relationship between the proliferation of life and atmospheric oxygen has given researchers new evidence of the hypothesized “oxygen overshoot.” According to this theory, photosynthesis from ancient microorganisms and the weathering of rocks created a huge amount of oxygen in the atmosphere that later waned as oxygen-emitting organisms exhausted their nutrient supply in the ocean and became less abundant. This situation is in contrast to the stable atmosphere we know on Earth today, where the oxygen created and consumed balances out. The researchers’ measurements of oxygen, sulfur and barium isotopes in barite support this oxygen overshoot hypothesis.

The research helps scientists hone their estimates of the size of the oxygen overshoot by revealing the significant biological consequences of oxygen levels above or below the capacity of the planet.

“Some of these oxygen estimates likely require too many microorganisms living in the ocean in Earth’s past,” said co-lead author Peter Crockford, a postdoctoral researcher at the Weizmann Institute of Science and Princeton University. “So we can now start to narrow in on what the composition of the atmosphere could have been through this biological angle.”

The research was supported by Stanford University McGee and Compton Grants, the Northern Scientific Training Program, NSERC, National Geographic, the American Philosophical Society, Geological Society of America and the Agouron Institute.

Reference:
Malcolm S. W. Hodgskiss, Peter W. Crockford, Yongbo Peng, Boswell A. Wing, Tristan J. Horner. A productivity collapse to end Earth’s Great Oxidation. Proceedings of the National Academy of Sciences, 2019; 116 (35): 17207 DOI: 10.1073/pnas.1900325116

Note: The above post is reprinted from materials provided by Stanford’s School of Earth, Energy & Environmental Sciences.

The ‘universal break-up criterion’ of hot, flowing lava?

August 31, 2019

Lava fountains at Kilauea in Hawaii created a spatter cone, which was estimated to be 180 feet tall in this June 2018 photo. Credit: U.S. Geological Survey

Thomas Jones’ “universal break-up criterion” won’t help with meltdowns of the heart, but it will help volcanologists study changing lava conditions in common volcanic eruptions.

Jones, of Rice University, studies the behavior of low-viscosity lava, the runny kind that’s found at most volcanoes. About two years ago, he began a series of lab experiments and field observations that provided the raw inputs for a new fluid dynamic model of lava break-up. The work is described in a paper in Nature Communications.

Low-viscosity lava is the red-hot, flowing type one might see at Hawaii’s famed Kilauea volcano, and Jones said it usually behaves in one of two ways.

“It can bubble or spew out, breaking into chunks that spatter about the vent, or it can flow smoothly, forming lava streams that can rapidly move downhill,” he said.

But that behavior can sometimes change quickly during the course of an eruption, and so can the associated dangers: While spattering eruptions throw hot lava fragments into the air, lava flows can threaten to destroy whole neighborhoods and towns.

Jones’ model, the first of its kind, allows scientists to calculate when an eruption will transition from a spattering spray to a flowing stream, based upon the liquid properties of the lava itself and the eruption conditions at the vent.

Jones said additional work is needed to refine the tool, and he looks forward to doing some of it himself.

“We will validate this by going to an active volcano, taking some high-speed videos and seeing when things break apart and under what conditions,” he said. “We also plan to look at the effect of adding bubbles and crystals, because real magmas aren’t as simple as the idealized liquid in our mathematical model. Real magmas can also have bubbles and crystals in them. I’m sure those will change things. We want to find out how.”

Jones said pairing the new model with real-time information about a lava’s liquid properties and eruption conditions could allow emergency officials to predict when an eruption will change style and become a hazard to at-risk communities.

“We want to use this as a forecasting tool for eruption behavior,” he said. “By developing a model of what’s happening in the subsurface we can then watch for indications that it’s about to cross the tipping point and change behavior.”

Reference:
T. J. Jones, C. D. Reynolds, S. C. Boothroyd. Fluid dynamic induced break-up during volcanic eruptions. Nature Communications, 2019; 10 (1) DOI: 10.1038/s41467-019-11750-4

Note: The above post is reprinted from materials provided by Rice University. Original written by Jade Boyd.

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