Geologists uncover new clues about largest mass extinction ever

A new study could help explain the driving force behind the largest mass extinction in the history of earth, known as the End-Permian Extinction.

The event, also known as the Great Dying, occurred around 250 million years ago when a massive volcanic eruption in what is today the Russian province of Siberia sent nearly 90 percent of all life right into extinction. Geologists call this eruption the Siberian Flood Basalts, and it ran for almost a million years.

"The scale of this extinction was so incredible that scientists have often wondered what made the Siberian Flood Basalts so much more deadly than other similar eruptions," said Michael Broadley, a postdoctoral researcher at the Centre for Petrographic and Geochemical Research in Vandœuvre-lès-Nancy, France, and lead author of the paper.

The work, which was published in Nature Geoscience, was co-authored by Lawrence (Larry) Taylor, the former director of the Planetary Geosciences Institute at the University of Tennessee, Knoxville. Taylor, whose prolific career at UT spanned 46 years, passed away in September 2017 at age 79.

According to Broadley, "Taylor was instrumental in supplying samples of mantle xenoliths, rock sections of the lithosphere [a section of the planet located between the crust and the mantle] that get captured by the passing magma and erupted to the surface during the volcanic explosion. Taylor also provided advice throughout the study."

Through the analysis of samples, Broadley and his team tried to determine the composition of the lithosphere. They found that before the Siberian Flood Basalts took place, the Siberian lithosphere was heavily loaded with chlorine, bromine, and iodine, all chemical elements from the halogen group. However, these elements seem to have disappeared after the volcanic eruption.

"We concluded that the large reservoir of halogens that was stored in the Siberian lithosphere was sent into the earth's atmosphere during the volcanic explosion, effectively destroying the ozone layer at the time and contributing to the mass extinction," Broadley said.

From Science Daily

Particles give absolute age of asteroid Itokawa

This is the cross section area of the particle collected from the asteroid Itokawa using Hayabusa spacecraft.

Understanding the origin and time evolution of near-Earth asteroids (NEAs) is an issue of scientific interest and practical importance because they are potentially hazardous to the Earth. However, when and how these NEAs were formed and what they suffered during their lifetime remain enigmas.

Japanese scientists, including those from Osaka University, closely examined particles collected from the asteroid Itokawa by the spacecraft Hayabusa, finding that the parent body of Itokawa was formed about 4.6 billion years ago when the solar system was born and that it was destroyed by a collision with another asteroid about 1.5 billion years ago. Their research results were published in Scientific Reports.

Focusing on a few micrometers of phosphate minerals, which are rarely found in Itokawa particles, the scientists performed precise isotope analyses of uranium (U) and lead (Pb) in Itokawa particles of about 50 ?m in diameter using Secondary Ion Mass Spectrometry (SIMS).

Lead author Kentaro Terada says, "By combining two U decay series, 238U-206Pb (with a half-life of 4.47 billion years) and 235U-207Pb (with a half-life of 700 million years), using four Itokawa particles, we clarified that phosphate minerals crystalized during a thermal metamorphism age (4.64±0.18 billion years ago) of Itokawa's parent body, experiencing shock metamorphism due to a catastrophic impact event by another body 1.51±0.85 billion years ago."

It has been reported that the mineralogy and geochemistry of the Itokawa particles resemble those of LL (LL stands for Low (total) iron, Low metal) chondrites, which frequently fall to the Earth.

However, the shock ages of Itokawa particles obtained from this study (1.5 billion years ago) are different from previously reported shock ages of shocked LL chondrites (4.2 billion years ago). This shows that the asteroid Itokawa had a time evolution different from that of the parent body of LL chondrites.

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Beluga whales and narwhals go through menopause

Female narwhal swimming at the surface, Baffin Island, Canada.

Scientists have discovered that beluga whales and narwhals go through the menopause -- taking the total number of species known to experience this to five.

Aside from humans, the species now known to experience menopause are all toothed whales -- belugas, narwhals, killer whales and short-finned pilot whales.

Almost all animals continue reproducing throughout their lives, and scientists have long been puzzled about why some have evolved to stop.

The new study, by the universities of Exeter and York and the Center for Whale Research, suggests menopause has evolved independently in three whale species (it may have evolved in a common ancestor of belugas and narwhals).

"For menopause to make sense in evolutionary terms, a species needs both a reason to stop reproducing and a reason to live on afterwards," said first author Dr Sam Ellis, of the University of Exeter.

"In killer whales, the reason to stop comes because both male and female offspring stay with their mothers for life -- so as a female ages, her group contains more and more of her children and grandchildren.

"This increasing relatedness means that, if she keeps having young, they compete with her own direct descendants for resources such as food.

"The reason to continue living is that older females are of great benefit to their offspring and grand-offspring. For example, their knowledge of where to find food helps groups survive."

The existence of menopause in killer whales is well documented due to more than four decades of detailed study.

Such information on the lives of belugas and narwhals is not available, but the study used data on dead whales from 16 species and found dormant ovaries in older beluga and narwhal females.

Based on the findings, the researchers predict that these species have social structures which -- as with killer whales -- mean females find themselves living among more and more close relatives as they age.

Research on ancestral humans suggests this was also the case for our ancestors. This, combined with the benefits of "late-life helping" -- where older females benefit the social group but do not reproduce -- may explain why menopause has evolved.

Senior author Professor Darren Croft said: "It's hard to study human behaviour in the modern world because it's so far removed from the conditions our ancestors lived in.

"Looking at other species like these toothed whales can help us establish how this unusual reproductive strategy has evolved."

Although individuals of many species may fail to reproduce late in life, the researchers looked for evidence of an "evolved strategy" where females had a significant post-reproductive lifespan.

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Jupiter had growth disorders

This is Jupiter's southern hemisphere photographed by NASA's Juno spacecraft.

With an equator diameter of around 143,000 kilometers, Jupiter is the largest planet in the solar system and has 300 times the mass of the Earth. The formation mechanism of giant planets like Jupiter has been a hotly debated topic for several decades. Now, astrophysicists of the Swiss National Centre of Competence in Research (NCCR) PlanetS of the Universities of Bern and Zürich and ETH Zürich have joined forces to explain previous puzzles about how Jupiter was formed and new measurements. The research results were published in the magazine Nature Astronomy.

"We could show that Jupiter grew in different, distinct phases," explains Julia Venturini, postdoc at the University of Zürich. "Especially interesting is that it is not the same kind of bodies that bring mass and energy," adds Yann Alibert, Science Officer of PlanetS and first author of the paper. First, the planetary embryo rapidly accreted small, centimeter-sized pebbles and quickly built a core during the initial one million years. The following two million years were dominated by slower accretion of larger, kilometer-sized rocks called planetesimals. They hit the growing planet with great energy, releasing heat. "During the first stage the pebbles brought the mass," Yann Alibert explains: "In the second phase, the planetesimals also added a bit of mass, but what is more important, they brought energy." After three million years, Jupiter had grown to a body of 50 Earth masses. Then, the third formation phase started dominated by gas runaway accretion leading to today's gas giant with more than 300 Earth masses.

Solar system divided into two parts

The new model for Jupiter's birth matches the meteorite data that were presented at a conference in the US last year. At first, Julia Venturini and Yann Alibert were puzzled when they listened to the results. Measurements of the composition of meteorites showed that in the primordial times of the solar system the solar nebula was divided into two regions during two million years. It could therefore be concluded that Jupiter acted as a kind of a barrier when it grew from 20 to 50 Earth masses. During this period, the forming planet must have perturbed the dust disk, creating an over-density that trapped the pebbles outside of its orbit. Therefore, material from outward regions could not mix with material of the inner ones until the planet reached enough mass to perturb and scatter rocks inwards.

"How could it have taken two million years for Jupiter to grow from 20 to 50 Earth masses?" asked Julia Venturini. "That seemed much too long," she explains: "That was the triggering question that motivated our study." A discussion by email started among NCCR PlanetS researchers of the Universities of Bern and Zürich and ETH Zürich and the following week the experts in the fields of astrophysics, cosmochemistry and hydrodynamics arranged a meeting in Bern. "In a couple of hours we knew what we had to calculate for our study," says Yann Alibert: "This was only possible within the framework of the NCCR, which links scientists from various fields."

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Effective fisheries management can reduce extinction risk of marine fish stocks

Numerous studies have highlighted that climate change impacts will put vulnerable marine species at risk of local and even global extinction; however, local actions through effective fisheries management can reduce the probability of those species' extinction risk by as much as 63 per cent, says a new UBC study.

Researchers looked at 825 exploited marine fish species across the global ocean, and analyzed their extinction risks due to climate change and fishing impacts. They calculated a conservation risk index for these species based on the ocean changes that they are, and will be, exposed to, their biological sensitivity to climate change, and potential ability to adapt. Their results showed that 499 of the assessed species are projected to experience very high risk from both overfishing and climate change under a 'business-as-usual' scenario, by 2050. They found that this risk level is equivalent to having at least one fifth of these species listed as vulnerable or endangered under the International Union for Conservation of Nature (IUCN) Red List of Endangered Species.

"Effective fisheries management plans, coupled with actions to limit greenhouse gas emissions, both separately, but especially in tandem, would have an immediate effect on the number of marine species that face extinction," said William Cheung, lead author and Associate Professor in the Institute for the Oceans and Fisheries at the University of British Columbia. "We can save hundreds of fish stocks from becoming endangered species with sustainable fisheries and low greenhouse gas emissions."

Sharks and rays have the highest extinction risk under 'business as usual' fishing and climate change scenarios. The Dusky smoothhound shark (Mustelus canis) is expected to be the hardest hit, with other species at high risk including Dungat grouper (Epinephelus goreensis), Tarpon (Megalops atlanticus), and Law croaker (Pseudotolithus senegallus). Many of these species are already considered endangered for non-climatic reasons, such as overfishing. This study indicated that the estimated combination of climate and fishing risks means that they are even more likely to become extinct.

The areas with more at-risk species due to climate change are in the tropical and subtropical oceans, while those species at risk due to fishing are distributed more broadly, with higher concentration in the North Atlantic and South Pacific Ocean.

"Our study showed the need to support adaptation to climate change, while insuring effective fisheries management in these regions," said Gabriel Reygondeau, a postdoctoral fellow at UBC's Institute for the Oceans and Fisheries and co-author on the paper. "Some actions are already underway; for example, nine nations and the European Union agreed to prohibit commercial fishing in the central Arctic Ocean for at least 16 years starting in 2017. Similar proactive planning for the potential interactions between climate change and fishing is needed."

From Science Daily

Tree species richness in Amazonian wetlands is three times greater than expected

Compilation of data from forest inventories and botanical collections generates a list of 3,615 tree species in wetland areas of the Amazon Basin. The account makes up for 53 percent of all tree species thus far confirmed for the entire Amazon region.

Throughout the alluvial plains of Amazonia, there are immense forests that are flooded for almost half the year. These Amazonian wetlands encompass a wide array of types of vegetation in or near stream gullies, including blackwater (igapó) and whitewater (várzea) inundation forest, swamp (pântano), white sand savanna (campina), and mangrove (mangue) types.

According to a new study, the region's wetlands are inhabited by 3,615 tree species -- three times more than previously estimated, making these the world's most diverse wetland forests in terms of tree species richness.

The study was supported by the São Paulo Research Foundation -- FAPESP and performed under the aegis of FAPESP's Research Program on Biodiversity Characterization, Conservation, Restoration and Sustainable Use (BIOTA-FAPESP). The results published in the journal PLOS ONE include the most comprehensive list of wetland tree species produced to date.

The authors compiled data available from tree inventories and botanical collections covering the nine countries spanned by the Amazon Basin.

"The list with the names of all the species is the main contribution made by this survey, which is open access. It will serve as a basis for future studies to fill the gap in botanical knowledge of the region's wetlands, especially on tributaries of the Solimões and Amazon rivers. If there were more inventories, the number of species could quickly triple again," said Bruno Garcia Luize, first author of the article and a doctoral researcher at São Paulo State University's Bioscience Institute (IB-UNESP) in Rio Claro, Brazil, who has a scholarship from FAPESP.

The number of species is threefold the number inventoried by previous researchers because the area covered by this study was larger, and more habitats were included.

"Prior studies focused only on whitewater inundation forests and floodplains. We included data for blackwater inundation forests, white sand savannas and mangroves, for example. Additionally, there is a very strong bias toward the Solimões-Amazon river system. We were able to add data for important effluents extracted from rare inventories of forests along the Purus, Juruá and Madeira, among others," Luize said.

For the researchers, the large number of tree species shows the importance of the role played by wetlands in creating and maintaining biodiversity in Amazonia. "This role has traditionally been assigned to the Andes, given the climate gradient there, but the fact that we found almost all families and genera to be well distributed, with species capable of colonizing wetland areas, suggests this ecosystem has been involved in the diversification process for a long time," said Thiago Sanna Freire Silva, a professor in São Paulo State University's Geography Department and coprincipal investigator of the project.

The hard lives of trees

The climate in Amazonia's wetland forests is distinctly seasonal, with fluctuations between dry periods and heavy rain leading to floods, during which the trees may be under water by as much as 8 meters. Wetland habitats can therefore be considered environmental filters that select individuals and species capable of tolerating recurrent flooding and drought during their lifespan.

"It's an incredibly beautiful environment," Luize said. "Blackwater inundation forests, for example, are among the most emblematic images of Amazonia. Tree embryos are submerged for four or five months while they develop. Moreover, monkeys swing through the tree crowns, and the pink river dolphin [Inia geoffrensis] feeds on fish deep in the forest."

Despite the difficult hydrological regimen, the Amazonian wetland tree species currently inventoried account for 53% of all the 6,727 tree species thus far confirmed for the entire Amazon region, according to the latest study.

For the researchers at São Paulo State University (UNESP), the high proportion of trees in wetlands corresponding to 30% of Amazonia's 7 million square kilometers is due to interchange between wetland and upland forest habitats.

Submerged tree roots can rot, and underwater respiration is difficult. "Flooded areas require a different tree metabolism," Luize said. "Some upland or terra firme species are able to tolerate inundation conditions, but studies have shown that populations in the different environments don't manage the same performance. Basically, this means that if you plant a seed from an upland species in a flooded area, it probably won't thrive and vice versa."

This difference suggests either that physiological adjustment occurs during the life of a tree or that the populations found in wetland areas have adapted to that environment. "As a result, we reach an extreme in which species are exclusive to wetland areas or only occur in upland areas," added the FAPESP scholarship holder.

Variations in variations

The duration of flooding in wetland areas varies considerably from one year to the next. "When floods last less and are less intense, the composition of the tree species pool resembles that found in upland areas. However, once these species have developed flood tolerance, even if it is initially a low level of tolerance, the flood provides an opportunity for them to colonize new waterlogged areas. This can lead to specialization in wetlands by some individuals, which become different from upland individuals," Freire Silva said.

Trees may become increasingly flood tolerant or evolve new forms of seed dispersal via water or fish. "Species diversity grows over thousands of years, increasing the variety of niches available," he noted.

South America is considered the region with the largest area of wetlands, a vital ecosystem for the planet's freshwater balance. The researchers stressed the importance of a better understanding of the variations in metabolic and physiological characteristics of both wetland and upland tree species.

"This is a point we need to investigate in more depth, but there are studies that show the effects of dry and wet seasons on forest productivity and on the carbon source-sink balance -- the uptake and release of carbon from or into the atmosphere," Luize said. "Tolerance of hydrological extremes, from drought to flood and back again, is a characteristic of floodable trees. It's important to understand these swings and exchanges on the scale of the basin as a whole."

Read more at Science Daily

New galaxy found?

Last summer, Case Western Reserve University undergraduate student Chris Carr spotted what looked like a "smudge" on deep sky images taken from the university's Burrell Schmidt telescope at Kitt Peak National Observatory in southwest Arizona.

It was so faint he hardly saw it. But he flagged it for Astronomy Professor Chris Mihos, with whom he'd been working the past two weeks, and explored the coordinates further.

What they found pointed to the detection of a new galaxy about 37 million lightyears away.

"I wasn't quite sure how to feel," Carr, now a rising senior studying physics and astronomy, said of the discovery. "It's not really something you are prepared for, especially this early.

"As Professor Mihos, our collaborators and I learned more about this bizarre smudge in our images, the significance of the discovery really began to come into focus, and that's when it sunk in that this was something truly special."

Announcing the finding on Twitter, Mihos thanked Carr for his "smudge-spotting eyes."

Carr's discovery is part of the Leo I galaxy group, and while its origins remain unclear, the researchers stated it is the "lowest surface brightness object ever detected via integrated light."

From Science Daily

Genetic analysis of Florida's invasive pythons reveals a tangled family tree

Burmese python in Everglades National Park.

A new genetic analysis of invasive pythons captured across South Florida finds the big constrictors are closely related to one another. In fact, most of them are genetically related as first or second cousins, according to a study by wildlife genetics experts at the U.S. Geological Survey.

The study also found that at least a few of the snakes in the invasive South Florida population are not 100 percent Burmese pythons. Instead, the genetic evidence shows at least 13 snakes out of about 400 studied are a cross between two separate species: Burmese pythons, which mostly inhabit wetlands, and Indian pythons, which prefer higher ground. The interbreeding between Burmese and Indian pythons probably took place before the animals became established in the South Florida environment, and may have given them greater adaptability in their new habitats.

The South Florida pythons spring from a tangled family tree, with consequences for the species' future spread that are hard to predict, the USGS scientists said.

"The snakes in South Florida are physically identifiable as Burmese pythons, but genetically, there seems to be a different, more complicated story," said Margaret Hunter, a USGS research geneticist and lead author on the study published in the journal Ecology and Evolution.

Burmese pythons have been reproducing in the Everglades since the 1980s, and have caused important environmental changes including the decline of small-mammal populations in South Florida.

The researchers analyzed tail tissue from about 400 Burmese pythons captured across a wide area, from southwest Florida and the Big Cypress National Preserve to the Everglades, southeast Miami-Dade County and the Florida Keys, between 2001 and 2012.

The researchers looked at nuclear DNA, which contains genetic material from both parents, to determine how much each animal had in common with others in the population. To express family relationships in statistical terms, they used a common type of calculation known as a relatedness value. For all snakes in the study, the average relatedness value was about midway between first and second cousins. That close kinship means the population as a whole is experiencing inbreeding, the researchers concluded.

When the researchers tested genetic material from a different part of the snakes' cells-mitochondrial DNA, inherited solely from the mother-they were surprised to find genetic signatures from the Indian python in 13 snakes.

Sometimes interbreeding between related species "can lead to hybrid vigor, that is, the best traits of two species are passed onto their offspring," Hunter said. "Hybrid vigor can potentially lead to a better ability to adapt to environmental stressors and changes. In an invasive population like the Burmese pythons in South Florida, this could result in a broader or more rapid distribution."

In the wild, related species typically avoid interbreeding by using different habitats. In their native Asia, Burmese pythons prefer wet habitats, while Indian pythons tend to stick to drier ones. In previous studies, scientists have observed South Florida's Burmese pythons in both wet and dry habitat types.

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Mutations in this molecule may have helped mammoths tolerate the cold

This is an image of human TRPV3 in the closed and open states viewed from outside the cell. Location of the region (N647) that is mutated in mammoths is highlighted.

Columbia University biomedical researchers have captured close-up views of TRPV3, a skin-cell ion channel that plays important roles in sensing temperature, itch, and pain.

In humans, defects in the protein can lead to skin diseases such as atopic dermatitis (a type of eczema), vitiligo (uneven skin coloration), skin cancer, and rosacea.

All vertebrate DNA, including the woolly mammoth genome, contains the TRPV3 gene. Though the mammoths lived in extremely cold environments, they descended from elephants that lived in the tropics. Researchers think that changes in the TRPV3 genes of mammoths may have helped them withstand lower temperatures.

Alexander Sobolevsky's lab at Columbia University Irving Medical Center used a powerful imaging technique called cryo-electron microscopy to take pictures of TRPV3 molecules. Initial 2D images were collected by freezing the molecules in an extremely thin, clear layer of ice and bombarding them with electrons. The researchers then used computational tools to convert the 2D images into detailed molecular 3D models.

Image of human TRPV3 in the closed and open states viewed from outside the cell. Location of the region (N647) that is mutated in mammoths is highlighted. Images: Alexander Sobolevsky / CUIMC

This is the first time scientists have gotten a glimpse of TRPV3 in atomic detail. The researchers were able to get images of the protein in two states, revealing how the channel opens and closes to let ions flow into skin cells.

This exchange of ions prompts the body to react to sensations such as pain, itchiness, and changes in temperature. The group also discovered how a small molecule with anti-cancer properties called 2-APB interacts with and controls the function of this channel.

The structures in this study provide clues about how mutations in TRPV3 affect the channel's ability to sense temperature and show that lipids -- molecules that make up most of the cell membrane -- contact the channel in several regions. Mammoth TRPV3 contains a mutation in one of these lipid-touching regions.

"Temperature affects the interaction of lipids and proteins," Sobolevsky says. "A mutation in the woolly mammoth channel would most likely affect this interaction and could explain how these animals adapted to their cold environment."

Researchers will use the structure to investigate how atomic changes to the protein cause it to malfunction in human diseases. "This study gives scientists a template they can use to design more effective drugs for treating these skin-related illnesses," said Appu Singh, PhD, a postdoctoral fellow in the Sobolevsky lab and a first author of the paper.

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Genetically engineered virus spins gold into beads

Electron microscope image of M13 spheroid-templated spiky gold nanobead with corresponding graphical illustration.

The race is on to find manufacturing techniques capable of arranging molecular and nanoscale objects with precision.

Engineers at the University of California, Riverside, have altered a virus to arrange gold atoms into spheroids measuring a few nanometers in diameter. The finding could make production of some electronic components cheaper, easier, and faster.

"Nature has been assembling complex, highly organized nanostructures for millennia with precision and specificity far superior to the most advanced technological approaches," said Elaine Haberer, a professor of electrical and computer engineering in UCR's Marlin and Rosemary Bourns College of Engineering and senior author of the paper describing the breakthrough. "By understanding and harnessing these capabilities, this extraordinary nanoscale precision can be used to tailor and build highly advanced materials with previously unattainable performance."

Viruses exist in a multitude of shapes and contain a wide range of receptors that bind to molecules. Genetically modifying the receptors to bind to ions of metals used in electronics causes these ions to "stick" to the virus, creating an object of the same size and shape. This procedure has been used to produce nanostructures used in battery electrodes, supercapacitors, sensors, biomedical tools, photocatalytic materials, and photovoltaics.

The virus' natural shape has limited the range of possible metal shapes. Most viruses can change volume under different scenarios, but resist the dramatic alterations to their basic architecture that would permit other forms.

The M13 bacteriophage, however, is more flexible. Bacteriophages are a type of virus that infects bacteria, in this case, gram-negative bacteria, such as Escherichia coli, which is ubiquitous in the digestive tracts of humans and animals. M13 bacteriophages genetically modified to bind with gold are usually used to form long, golden nanowires.

Studies of the infection process of the M13 bacteriophage have shown the virus can be converted to a spheroid upon interaction with water and chloroform. Yet, until now, the M13 spheroid has been completely unexplored as a nanomaterial template.

Haberer's group added a gold ion solution to M13 spheroids, creating gold nanobeads that are spiky and hollow.

"The novelty of our work lies in the optimization and demonstration of a viral template, which overcomes the geometric constraints associated with most other viruses," Haberer said. "We used a simple conversion process to make the M13 virus synthesize inorganic spherical nanoshells tens of nanometers in diameter, as well as nanowires nearly 1 micron in length."

The researchers are using the gold nanobeads to remove pollutants from wastewater through enhanced photocatalytic behavior.

The work enhances the utility of the M13 bacteriophage as a scaffold for nanomaterial synthesis. The researchers believe the M13 bacteriophage template transformation scheme described in the paper can be extended to related bacteriophages.

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