вторник, 12 марта 2019 г.

Arctic change has widespread impacts

As the Arctic warms faster than the rest of the globe, permafrost, land ice and sea ice are disappearing at unprecedented rates. And these changes not only affect the infrastructure, economies and cultures of the Arctic, they have significant impacts elsewhere as well—according to a commentary in Earth’s Future, led by research scientist Twila Moon of the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder.











Arctic change has widespread impacts
Light reflects off Arctic sea ice [Credit: NASA]

“To many, the Arctic seems like a distant universe—one that could never impact their lives,” said Moon. “But the reality is, changes in the Arctic are increasingly affecting the rest of the world, causing amplified climate change, sea level rise, coastal flooding and more devastating storms.”


Sea Level Rise


The melting of land ice has contributed to 60 percent of sea level rise since 1972. Arctic land ice comprises over two million square acres, and studies have confirmed this area is diminishing rapidly due to climate change. In addition, most land ice in this region is thinning. If current warming trajectories are maintained, Arctic land ice is expected to be a major contributor to projected global sea level rise, contributing up to one meter this century. Three out of four of the U.S.’s largest cities—New York, Los Angeles and Houston—are coastal and 39 percent of the U.S. population lives in shoreline counties. As sea levels continue to rise, coastal cities around the U.S. and world will be increasingly forced to deal with the impacts, including flooding, freshwater contamination, coastal erosion, higher storm surges and more.


Extreme Weather Events


In addition to the increased storm surges and flood events caused by sea level rise, a current hypothesis states that changes in the Arctic jet stream may be significantly affecting storms and extreme weather events, including snow storms and droughts, in the continental U.S. as well as Canada, Europe and Asia. For example, Arctic warming has been linked to a recent extreme drought in California.


Infrastructure Damage


Under the “business as usual” emission scenario, the Intergovernmental Panel on Climate Change RCP8.5 estimates that Alaska will face $5.5 billion dollars in infrastructure damage between 2015 and 2099. Almost half of this will be directly due to permafrost thaw. In addition, this permafrost thaw will release significant amounts of carbon dioxide and methane into the atmosphere, contributing to further warming of the planet.


Coastal Erosion and Arctic Amplification


Sea ice extent and sea ice thickness have both declined in the past several decades. This sea ice loss has caused dramatic coastal erosion in Siberia and Alaska, and has serious global consequences as sea ice helps to regulate Earth’s climate by reflecting incoming solar radiation. As sea ice cover declines, Arctic warming is amplified due to these decreases in surface reflectivity.


Looking Forward


“As the Arctic continues to warm faster than the rest of the globe, we’ll continue to see impacts worldwide, including in tropical and temperate countries with big cities, large economies, and lots of infrastructure,” said Moon. “If we want to safeguard our people and society, we need to act now to both reduce emissions to curb warming and to prepare for the inevitable changes already set in motion.”


Source: University of Colorado at Boulder [March 08, 2019]



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Southern Ocean acidification puts marine organisms at risk

New research indicates that acidification of the Southern Ocean will cause a layer of water to form below the surface that corrodes the shells of some sea snails, an outcome that could disrupt marine food webs.











Southern Ocean acidification puts marine organisms at risk
Pteropods, a type of sea snail like the one shown here, could see reduced habitat
from acidification in the Southern Ocean [Credit: Alexander Semenov]

University of Colorado Boulder and University of Alaska Fairbanks researchers collaborated on the study, which was published today in the journal Nature Climate Change.


Pteropods, a type of sea snail, typically live in the upper 300 meters of the water column in the Southern Ocean. Due to acidification by 2100, they may only be able to thrive on average in the top 83 meters of water. That’s assuming the current level of carbon dioxide released into the atmosphere continues.


Gabriela Negrete-García, who led the study as a CU Boulder undergraduate, made the forecast based on data from a global climate model and water samples from the Southern Ocean, which surrounds Antarctica.


Pteropods rely on naturally occurring carbonate ions to build and maintain their aragonite mineral shells. As oceans absorb human-made atmospheric carbon dioxide, the water’s chemistry is altered, lowering its pH and reducing the concentration of these carbonate building blocks.


The study identified the depth, known as a horizon, at which the carbonate ion concentration of sea water is inadequate to sustain aragonite shell production.











Southern Ocean acidification puts marine organisms at risk
This figure illustrates a new relatively shallow layer emerging in the Southern Ocean
where the concentration of carbonate ions in the water is too low for pteropods
to maintain their shells [Credit: International Arctic Research Center]

“In this study we found not just one horizon at a deep depth, but suddenly we see a second shallow horizon emerge that encroaches into pteropod habitat,” said Claudine Hauri, co-author and a chemical oceanographer at UAF’s International Arctic Research Center.


The present-day horizon exceeds 1,000 meters across most of the Southern Ocean, a depth that is well below pteropod habitat.


The new shallow horizon would be a layer of corrosive water beginning at an average depth of 83 meters, greatly reducing viable pteropod habitat. If that occurs, it could impact marine food webs significantly and lead to cascading changes across ocean ecosystems, including disruptions of vital global fisheries.


The study forecast ocean acidification under several carbon dioxide emission scenarios.


The individual simulations created by the model differed on when the shallow horizon will emerge. Some estimate it began as early as 2006 in discrete locations, while others predict it will begin as late as 2038. The research suggests that the change may be inevitable in large regions of the Southern Ocean, regardless of future mitigation efforts.











Southern Ocean acidification puts marine organisms at risk
Icebergs float in the Southern Ocean near the Western Arctic Peninsula
[Credit: Andrew McDonnell]

“If emissions were curbed tomorrow, this suddenly shallow horizon would still appear, even if possibly delayed,” said Nicole Lovenduski of CU Boulder. “And that inevitability, along with the lack of time for organisms to adapt, is most concerning.”
The Southern Ocean’s cold water is particularly vulnerable to acidification. The cold facilitates naturally low carbonate ion concentrations. Persistent upwelling also brings carbon-rich water close to the surface, further decreasing carbonate ion concentrations.


“These factors put us closer to a threshold that might be harmful for a lot of organisms,” said Hauri.


There are important parallels between the cold Southern Ocean and northern seas that could indicate that Alaska’s coastal waters are similarly at risk. Hauri has now developed an Alaska regional model to explore ocean acidification impacts around the state.


Source: University of Alaska Fairbanks [March 11, 2019]



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Genes that evolve from scratch expand protein diversity

One of the most important questions in biology is how rapidly new proteins evolve in organisms. Proteins are the building blocks that carry out the basic functions of life. As the genes that produce them change, the proteins change as well, introducing new functionality or traits that can eventually lead to the evolution of new species.











Genes that evolve from scratch expand protein diversity
Oryza sativa is the most common type of rice used as a food crop
[Credit: University of Chicago Medical Center]

A new study published in Nature Ecology and Evolution led by scientists from the University of Chicago challenges one of the classic assumptions about how new proteins evolve. The research shows that random, noncoding sections of DNA can quickly evolve to produce new proteins. These de novo, or “from scratch,” genes provide a new, unexplored way that proteins evolve and contribute to biodiversity.


“Using a big genome comparison, we show that noncoding sequences can evolve into completely novel proteins. That’s a huge discovery,” said Manyuan Long, PhD, the Edna K. Papazian Distinguished Service Professor of Ecology and Evolution at UChicago and senior author of the new study.


A third way for genes to evolve


For decades, scientists believed that there were only two ways new genes evolved: duplication and divergence or recombination. During the normal process of replication and repair, a section of DNA gets copied and creates a duplicate version of the gene. Then, one of these copies may acquire mutations that change its functionality enough that it diverges and becomes a distinct new gene. With recombination, pieces of genetic material are reshuffled to create new combinations and new genes. However, these two methods only account for a relatively small number of proteins, given the total number of possible combinations of amino acids that comprise them.


Scientists have long wondered about a third mechanism, where de novo genes could evolve from scratch. All organisms have long stretches of genetic material that do not encode proteins, sometimes up to 97 percent of the total genome. Is it possible for these noncoding sections to acquire mutations that suddenly make them functional?


This has been difficult to study because it requires high-quality reference genomes from several closely related species that show both the ancestral, noncoding sequences and subsequent new genes that evolved from them. Without this clear, visible line of evolution, there’s no way to prove it’s truly a de novo gene. The supposed new genes reported previously could just be an “orphaned gene” that diverged or transferred from unrelated organisms at some point, then all traces of its predecessors disappeared.


To overcome these challenges, Long’s team took advantage of 13 new genomes sequenced and annotated recently from 11 closely-related species of rice plants, including Oryza sativa, the most common food crop. He worked with groups headed by Prof. Rod Wing at the University of Arizona. Prof. Yidan Ouyang from Huazhong Agricultural University, China, also led a team that cultivated their own rice plants in Hainan, a tropical island off the southern coast of China, and harvested them for proteomics sampling.


After analyzing the genomes of these plants, they detected at least 175 de novo genes. Further mass spectrometry analysis of protein activity was conducted by another group led by Prof. Siqi Liu at BGI-Shenzhen, a genome sequencing center located in Shenzhen, Guangdong, China. They found evidence that 57 percent of these genes actually translated into new proteins, including more than 300 new peptides.


With this first, large dataset of authentic de novo genes, Long’s team detected a pattern in their evolution. It began with the early evolution of expression, followed by subsequent mutation into protein coding potentials for almost all de novo genes.


“This makes sense given the widely observed expression of intergenic regions in various organisms,” said Li Zhang, a postdoctoral researcher at UChicago and lead author of the article.


Long says that the Oryza plants are good genomes to search for de novo genes because they are relatively young–you can still see evidence of evolution in their existing genomes.


“The 11 species diverged from each other only about three to four million years ago, so they are all young species,” he said. “For that reason, when we sequence the genomes, all the sequences are highly similar. They haven’t accumulated multiple generations of changes, so all the previous non-coding sections are still there.”


Long and his team next want to study the new proteins to further understand their function and evolution and see if there is something unique about their structure. If de novo genes open up an unexplored path for evolution, they could reveal mechanisms for creating new and improved cellular functions. For instance, the researchers detected evidence of natural selection acting to fix insertions and deletions in the genome to generate new protein sequences, and the sequence’s evolution toward improved functions.


“The new proteins may make certain functions better, or help regulate the genes better,” he said. “Each step of the way, they can bring some kind of benefit to the organism until it gradually becomes fixed in the genome.”


Author: Matt Wood | Source: University of Chicago Medical Center [March 11, 2019]



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Genetic origins of the saffron crocus explained

With a price tag of up to 30,000 euro per kilogram, saffron is the most expensive spice in the world. Sometimes it even exceeds the price of gold. Its typical aroma is produced by the apocarotenoid Safranal. Saffron is harvested from the flowers of the saffron crocus (Crocus sativus), which blooms solely in autumn. In order to yield one kilogram of saffron — skilled pickers can collect 60 to 80 grams per day — 150,000 to 200,000 flowers must be harvested by hand. Subsequently, the three stigmas of each flower are also separated manually and dried. These threads then constitute the spice saffron. Approximately 200 tonnes of saffron threads are harvested worldwide each year.











Genetic origins of the saffron crocus explained
Flower of the saffron crocus with three orange carpels [Credit: TUD/Sarah Breitenbach
& FISH chromosome analysis]

For many farmers in Mediterranean countries, Kashmir, India, Afghanistan, Iran and Pakistan, the production of saffron is the main source of income, since the saffron crocus also thrives in soils that cannot be utilised for agriculture. Even in the vicinity of Dresden, the cultivation of saffron has been recently restored after a centuries-long interruption that began in 1570. These local growers swear by the excellent quality of German saffron. Frost makes the plants more robust and the filaments more fragrant. Over the past millennia, saffron has been used as a spice, dye and as a medicine to treat rheumatism and alcohol addictions. For example, saffron was also used as a painkiller during childbirth and for “lady’s malaise.” According to Greek mythology, Zeus slept on a bed of saffron. In the 14th century “Saffron War of Balsthal,” Swiss merchants were even ambushed and robbed.
Due to its immense value, ground saffron is frequently adulterated by the addition of substances such as pollen from other flowers. Experts therefore advise consumers to buy whole threads.


The saffron crocus is a triploid hybrid species, is sterile and cannot be bred. Although it has been cultivated for more than 3,500 years, all plants cultivated worldwide originate only from daughter bulbs. For almost 100 years, there has been controversy as to the possible parent species of the saffron crocus are. If the parent species were known, changes could be inserted into the crocus genome by new breeding.


It is precisely this mystery that Dresden biologists have now solved. “We have managed to understand the origins of the saffron crocus and shed light on the parent species using molecular and cytogenetic methods,” says Thomas Schmidt, Professor of Plant Cell and Molecular Biology at TU Dresden’s Institute of Botany. “Our paper Adding color to a century-old enigma: multi-color chromosome identification unravels the autotriploid nature of saffron (Crocus sativus) as a hybrid of wild Crocus cartwrightianus cytotypes was accepted for publication in the journal New Phytologist. The paper is the title story for the April print issue and the source of the cover picture for the edition published on 8th May.”


The saffron crocus therefore is descended from only one species, the wild species Crocus cartwrightianus that is found in Greece. Through saffron crocus genome sequencing and comparative chromosome analysis (Fluorescence in situ hybridization, FISH) of different crocus species, Dresden biologists were able to demonstrate that genomes of two Crocus cartwrightianus individuals with slight chromosomal differences are fused. These findings conclude the centuries-long search for the origins of this mythical plant.


By the way: In order to preserve the fragrance, saffron should not be cooked for long. It is best to soak the threads in warm water for a few minutes and add them to the dish with the liquid when it is almost finished cooking. An even more intense colour can be obtained if the saffron threads are freshly ground.


Source: Technische Universität Dresden [March 11, 2019]



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A world full of copper helped animals colonise the Earth

An abundance of copper played an equally crucial role to oxygen in helping the rise and spread of the earliest animals 700 million years ago.











A world full of copper helped animals colonise the Earth
Copper is an essential building block of life, creating proteins that were crucial in helping
early animal life develop respiratory systems [Credit: University of Aberdeen]

Scientists have analysed geological records to prove that the level of copper in the environment increased dramatically at the same time as the first animals started to emerge.


Copper is an essential building block of life, creating proteins that were crucial in helping early animal life—such as jellyfish and sea sponges—develop respiratory systems.


The relatively low level of oxygen in the environment during the Neoproterozoic period—when the first multicellular life began to emerge—has led scientists to investigate other factors that might have been involved.


By discovering a dramatic increase in the availability of copper during this period, geologists from the Universities of Aberdeen and Glasgow have revealed the crucial role it played in helping early life thrive.


Professor John Parnell, from the University of Aberdeen’s School of Geosciences, led the study, published in Scientific Reports.


He said: “Our research shows that across the planet, magmas from deep in the Earth brought copper-bearing volcanic rocks to the surface about 800 million years ago.


“These rocks were weathered to release abundant copper into the environment, just as animals were starting to appear.


“Animals use copper in several ways, but two critical functions of the metal give animals the strength to support themselves, and the ability to breathe oxygen from the air by making compounds called copper proteins, which are essential to the way they live.


“Oxygen in the air had the double role of weathering rocks to provide copper, and of letting animals breathe, which they could do using their copper proteins. Oxygen was actually toxic to earlier primitive life, but copper gave animals the means to cope with it and use it to their advantage—it was a clever bit of evolution.”


Fellow author Professor Adrian Boyce of the University of Glasgow added: “It’s no coincidence that some of the biggest copper ore deposits in the world, in Africa, formed just as the first animals were starting to emerge. Life and rocks were in harmony.”


Source: University of Aberdeen [March 11, 2019]



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Ancient records prompt rethink of animal evolution timeline

Scientists are rethinking a major milestone in animal evolution, after gaining fresh insights into how life on Earth diversified millions of years ago.











Ancient records prompt rethink of animal evolution timeline
Researchers conducting fieldwork in Namibia as part of a previous study 
[Credit: Rachel Wood]

Bursts of evolutionary activity that increased the number and variety of animals began earlier, occurred over a longer timeframe, and were more frequent than previously thought, researchers say.


Their findings challenge a long-held theory that suggests the huge expansion in the types of animals on the planet more than 500 million years ago was triggered by a single, rapid surge of evolution – known as the Cambrian Explosion.


Geoscientists from the University of Edinburgh re-assessed the timeline of early animal evolution by analysing records of fossil discoveries and environmental change.


Until now, the Cambrian Explosion – which took place between 540 and 520 million years ago – was thought to have given rise to almost all the early ancestors of present-day animals.


Scientists say, however, that it was probably just one in a series of similar events, the first of which took place at least 571 million years ago during the late Ediacaran Period.


These bursts of evolutionary activity may have coincided with dramatic fluctuations in the levels of oxygen and essential nutrients in the oceans, the team says.


The review is published in the journal Nature Ecology & Evolution. It was supported by the Natural Environment Research Council. The research also involved the Universities of Bristol, Cambridge and Helsinki, Tokyo Institute of Technology, Japan, and Memorial University of Newfoundland in Canada.


Professor Rachel Wood, of the University of Edinburgh’s School of GeoSciences, who led the study, said: “Integrating data from the fossil record with that of environmental changes that affected the whole planet is revealing the patterns and drivers of the rise of complex life on Earth. We used to think early animals emerged rapidly following a single evolutionary event, but our findings suggest it actually happened in stages.”


Source: University of Edinburgh [March 11, 2019]



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2019 March 12 Touchdown on Asteroid Ryugu Video Credit:…


2019 March 12


Touchdown on Asteroid Ryugu
Video Credit: JAXA


Explanation: Last month, humanity bounced a robot off an asteroid. The main reason was to collect a surface sample. Despite concern over finding a safely reboundable touchdown spot, Japan’s robotic Hayabusa2 spacecraft successfully touched down – and bounced right back from – asteroid Ryugu. Before impact, Hayabusa2 fired a small bullet into 162173 Ryugu to scattered surface material and increase the chance that Hayabusa2 would be able to capture some. Next month, Hayabusa2 will fire a much larger bullet into Ryugu in an effort to capture sub-surface material. Near the end of this year, Hayabusa2 is scheduled to depart Ryugu and begin a looping trip back to Earth, hopefully returning small pieces of this near-Earth asteroid in late 2020. Studying Ryugu could tell humanity not only about the minor planet’s surface and interior, but about what materials were available in the early Solar System for the development of life.


∞ Source: apod.nasa.gov/apod/ap190312.html


Chimpanzees lose their behavioural and cultural diversity

Chimpanzees exhibit exceptionally high levels of behavioral diversity compared to all other non-human species. This diversity has been documented in a variety of contexts, including the extraction of food resources, communication and thermoregulation. Many of these behaviors are assumed to be socially learned and group-specific, supporting the existence of chimpanzee cultures.











Chimpanzees lose their behavioural and cultural diversity
Male chimpanzees of the Rekambo community groom one another at Loango National Parl, Gabon
[Credit: © Tobias Deschner/Loango Chimpanzee Project]

As all other great apes, chimpanzees have come under enormous pressure by human activities, leading to a change of the natural environment. Their prime habitat, tropical rainforests and savanna woodlands, are increasingly converted to agricultural farmland, plantations and settlements, or otherwise degraded by the extraction of natural resources and infrastructure development.


Much of the empirical work and resulting debate on the loss of wildlife biodiversity has been conducted in the context of species decline or loss of genetic diversity and ecosystem functions.


However, behavioural diversity is also a facet of biodiversity. Due to limited empirical data, until now it had been unclear whether behavioral diversity would similarly be negatively affected by human impact.


Data from 15 countries


An international research team, led by Hjalmar Kühl and Ammie Kalan of the Department of Primatology at the Max Planck Institute for Evolutionary Anthropology and the German Centre for Integrative Biodiversity Research (iDiv), compiled an unprecedented dataset on 31 chimpanzee behaviors across 144 social groups or communities, located throughout the entire geographic range of wild chimpanzees.


Whereas part of this information was already available in the scientific literature, the international research team also conducted extensive field work at 46 locations, as part of the Pan African Programme, across 15 chimpanzee range countries over the last nine years.


The particular set of behaviours considered in this study included the extraction and consumption of termites, ants, algae, nuts and honey; the use of tools for hunting or digging for tubers, and the use of stones, pools and caves among several others.











Chimpanzees lose their behavioural and cultural diversity
Chimpanzees in the Tai forest of Cote d’Ivoire crack nuts with a stone hammer
[Credit: © Liran Samuni/Tai Chimpanzee Project]

The occurrence of behaviors at a given site was investigated with respect to an aggregate measure of human impact. This measure integrates multiple levels of human impact, including human population density, roads, rivers and forest cover, all indicators for the level of disturbance and the degree of land cover change found in chimpanzee habitats.


“The analysis revealed a strong and robust pattern: chimpanzees had reduced behavioural diversity at sites where human impact was high”, explains Kalan, a researcher at the Max Planck Institute for Evolutionary Anthropology.


“This pattern was consistent, independent of the grouping or categorization of behaviours. On average, chimpanzee behavioural diversity was reduced by 88 percent when human impact was highest compared to locations with the least human impact.”


Potential mechanisms for loss of behaviours


As is known for humans, population size plays a major role in maintaining cultural traits and a similar mechanism may function in chimpanzees.


Chimpanzees may also avoid conspicuous behaviours that inform hunters about their presence, such as nut cracking. Habitat degradation and resource depletion may also reduce opportunities for social learning and thus prevent the transfer of local traditions from one generation to the next.


Lastly, climate change may also be important, as it may influence the production of important food resources and make their availability unpredictable. Very likely a combination of these potential mechanisms has caused the observed reduction in chimpanzee behavioral diversity.



“Our findings suggest that strategies for the conservation of biodiversity should be extended to include the protection of animal behavioral diversity as well”, says Kühl, an ecologist at the iDiv research center and the Max Planck Institute for Evolutionary Anthropology.


“Locations with exceptional sets of behaviors may be protected as ‘Chimpanzee cultural heritage sites’ and this concept can be extended to other species with high degree of cultural variability as well, including orangutans, capuchin monkeys or whales.”


These propositions are in accordance with existing biodiversity conservation efforts, such as the Convention on Biological Diversity or the Convention on the Conservation of Migratory Species of Wild Animals, of the United Nations Environment Programme, which calls for the protection of biological diversity in its entirety, including behavioural diversity of culturally rich wildlife.


The study is published in the journal Science.


Source: Max Planck Institute for Evolutionary Anthropology [March 07, 2019]



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Study confirms horseshoe crabs are really relatives of spiders, scorpions

Blue-blooded and armored with 10 spindly legs, horseshoe crabs have perhaps always seemed a bit out of place.











Study confirms horseshoe crabs are really relatives of spiders, scorpions
University of Wisconsin-Madison postdoctoral researcher Jesus Ballesteros holds a small horseshoe crab.
A study he led with Integrative Biology Professor Prashant Sharma used robust genetic analysis
 to demonstrate that horseshoe crabs are arachnids like spiders, scorpions and ticks
[Credit: Jesus Ballesteros]

First thought to be closely related to crabs, lobsters and other crustaceans, in 1881 evolutionary biologist E. Ray Lankester placed them solidly in a group more similar to spiders and scorpions. Horseshoe crabs have since been thought to be ancestors of the arachnids, but molecular sequence data have always been sparse enough to cast doubt.


University of Wisconsin-Madison evolutionary biologists Jesús Ballesteros and Prashant Sharma hope, then, that their recent study published in the journal Systematic Biology helps firmly plant ancient horseshoe crabs within the arachnid family tree.


By analyzing troves of genetic data and considering a vast number of possible ways to examine it, the scientists now have a high degree of confidence that horseshoe crabs do indeed belong within the arachnids.


“By showing that horseshoe crabs are part of the arachnid radiation, instead of a lineage closely related to but independent of arachnids, all previous hypotheses on the evolution of arachnids need to be revised,” says Ballesteros, a postdoctoral researcher in Sharma’s lab. “It’s a major shift in our understanding of arthropod evolution.”


Arthropods are often considered the most successful animals on the planet since they occupy land, water and sky and include more than a million species. This grouping includes insects, crustaceans and arachnids.


Horseshoe crabs have been challenging to classify within the arthropods because analysis of the animals’ genome has repeatedly shown them to be related to arachnids like spiders, scorpions, mites, ticks and lesser-known creatures such as vinegaroons. Yet, “scientists assumed it was an error, that there was a problem with the data,” says Ballesteros.


Moreover, horseshoe crabs possess a mix of physical characteristics observed among a variety of arthropods. They are hard-shelled like crabs but are the only marine animals known to breathe with book gills, which resemble the book lungs spiders and scorpions use to survive on land.


Only four species of horseshoe crabs are alive today, but the group first appeared in the fossil record about 450 million years ago, together with mysterious, extinct lineages like sea scorpions. These living fossils have survived major mass extinction events and today their blood is used by the biomedical industry to test for bacterial contamination.


Age is just one of the problems inherent in tracing their evolution, say Ballesteros and Sharma, since searching back through time to find a common ancestor is not easy to accomplish. And evidence from the fossil record and genetics indicates evolution happened quickly among these groups of animals, convoluting their relationships to one another.


“One of the most challenging aspects of building the tree of life is differentiating old radiations, these ancient bursts of speciation,” says Sharma, a professor of integrative biology. “It is difficult to resolve without large amounts of genetic data.”


Even then, genetic comparisons become tricky when looking at the histories of genes that can either unite or separate species. Some genetic changes can be misleading, suggesting relationships where none exist or dismissing connections that do. This is owed to phenomena such as incomplete lineage sorting or lateral gene transfer, by which assortments of genes aren’t cleanly made across the evolution of species.


Ballesteros tested the complicated relationships between the trickiest genes by comparing the complete genomes of three out of the four living horseshoe crab species against the genome sequences of 50 other arthropod species, including water fleas, centipedes and harvestmen.


Using a complex set of matrices, taking care not to introduce biases in his analysis, he painstakingly teased the data apart. Still, no matter which way Ballesteros conducted his analysis, he found horseshoe crabs nested within the arachnid family tree.


He says his approach serves as a cautionary tale to other evolutionary biologists who may be inclined to cherry-pick the data that seem most reliable, or to toss out data that don’t seem to fit. Researchers could, for example, “force” their data to place horseshoe crabs among crustaceans, says Sharma, but it wouldn’t be accurate. The research team tried this and found hundreds of genes supporting incorrect trees.


Ballesteros encourages others to subject their evolutionary data to this kind of rigorous methodology, because “evolution is complicated.”


Why horseshoe crabs are water dwellers while other arachnids colonized land remains an open question. These animals belong to a group called Chelicerata, which also includes sea spiders. Sea spiders are marine arthropods like horseshoe crabs, but they are not arachnids.


“What the study concludes is that the conquest of the land by arachnids is more complex than a single tradition event,” says Ballesteros.


It’s possible the common ancestor of arachnids evolved in water and only groups like spiders and scorpions made it to land. Or, a common ancestor may have evolved on land and then horseshoe crabs recolonized the sea.


“The big question we are after is the history of terrestrialization,” says Sharma.


For Ballesteros, who is now studying the evolution of blindness in spiders living deep within caves in Israel, his motivations get to the heart of human nature itself.


“I get to look with childish curiosity and ask: ‘How did all this diversity come to be?'” he says. “It’s incredible what exists, and I never thought I would have the privilege to be able to do this.”


Author: Kelly April Tyrrell | Source: University of Wisconsin-Madison [March 08, 2019]



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New wallaby-sized dinosaur from the ancient Australian-Antarctic rift valley

A new, wallaby-sized herbivorous dinosaur has been identified from five fossilized upper jaws in 125 million year old rocks from the Cretaceous period of Victoria, southeastern Australia.











New wallaby-sized dinosaur from the ancient Australian-Antarctic rift valley
Artist’s impression of a Galleonosaurus dorisae herd on a riverbank in the Australian-Antarctic rift valley during
the Early Cretaceous, 125 million years ago. The newly-named, dinosaur wallaby-sized herbivorous dinosaur,
was identified from five fossilized upper jaws in 125-million-year-old rocks from the Cretaceous
period of Victoria, southeastern Australia [Credit: copyright James Kuether]

Reported in the Journal of Paleontology, the new dinosaur is named “Galleonosaurus dorisae,” and is the first dinosaur named from the Gippsland region of Australia in 16 years. According to Dr Matthew Herne, a Postdoctoral Fellow at the University of New England, NSW, and lead author of the new study, “the jaws of Galleonosaurus dorisae include young to mature individuals–the first time an age range has been identified from the jaws of an Australian dinosaur.”


Galleonosaurus was a small-bodied herbivorous dinosaur within the large family called ornithopods. “These small dinosaurs would have been agile runners on their powerful hind legs,” explained Dr Herne.


The name Galleonosaurus dorisae refers to the shape of the upper jaw, resembling the upturned hull of a sailing ship called a galleon, and also honours the work of Dr Doris Seegets-Villiers, who produced her PhD thesis on the palaeontology of the locality where the fossils were discovered.


Galleonosaurus is the fifth small ornithopod genus named from Victoria, which according to Dr Herne, “confirms that on a global scale, the diversity of these small-bodied dinosaurs had been unusually high in the ancient rift valley that once extended between the spreading continents of Australia and Antarctica.” Small ornithopods appear to have thrived on the vast forested floodplain within the ancient rift valley.


At the time of Galleonosaurus, sediments were shed from a four thousand km long massif of large, actively erupting volcanoes that once existed along the eastern margin of the Australian continent. Some of these sediments were carried westward by large rivers into the Australian-Antarctic rift valley where they formed deep sedimentary basins. However, as these sediments washed down the rivers of the rift valley the bones of dinosaurs, such as Galleonosaurus and other vertebrates, along with the logs of fallen trees, became mixed in. According to Dr Herne, “this land has now vanished, but as ‘time-travellers’ we get snapshots of this remarkable world via the rocks and fossils exposed along the coast of Victoria.”











New wallaby-sized dinosaur from the ancient Australian-Antarctic rift valley
Fossils and 3D CT model of the newly named dinosaur, Galleonosaurus dorisae. The wallaby-sized herbivorous dinosaur
has been identified from five fossilized upper jaws in 125-million-year-old rocks from the Cretaceous period
of Victoria, southeastern Australia [Credit: Matthew Herne]

The new article shows that Galleonosaurus dorisae is a close relative of Diluvicursor pickeringi; another small ornithopod named by Dr Herne and his team in 2018, from excavations along the Otway coast to the west of the Gippsland region. Interestingly, “the jaws of Galleonosaurus and the partial skeleton of Diluvicursor were similarly buried in volcanic sediments on the floor of deep powerful rivers,” explained Dr Herne. “However, Galleonosaurus is about 12 million years older than Diluvicursor, showing that the evolutionary history of dinosaurs in the Australian-Antarctic rift had been lengthy.”


The jaws of Galleonosaurus were discovered by volunteers of the Dinosaur Dreaming project during excavations near the town of Inverloch. The most complete jaw and the key specimen carrying the name Galleonosaurus dorisae was discovered in 2008 by the seasoned fossil hunter Gerrit (‘Gerry’) Kool, from the nearby town of Wonthaggi. Gerry and his wife Lesley have been instrumental in organizing the Dinosaur Dreaming excavations along the Victorian coast for 25 years.


Prior to discovery of Galleonosaurus dorisae, the only other ornithopod known from the Gippsland region was Qantassaurus intrepidus, named in 1999. However, Qantassaurus had a shorter more robust snout than that of Galleonosaurus, explained Dr Herne, who added, “we consider that these two, similarly-sized dinosaurs fed on different plant types, which would have allowed them to coexist.”


The new study reveals that the ornithopods from Victoria are closely related to those from Patagonia in Argentina. “We are steadily building a picture of terrestrial dinosaur interchange between the shifting Gondwanan continents of Australia, South America and Antarctica during the Cretaceous period,” added Dr Herne


These are exciting times for dinosaur research, explained Dr Herne: “Using advanced techniques, such as 3D micro-CT scanning and printing, new anatomical information is being revealed on dinosaurs such as Galleonosaurus dorisae. These techniques are helping us to delve deeper into the mysterious world of dinosaur ecology–what they ate, how they moved and how they coexisted–and their evolutionary relationships with dinosaurs from other continents.”


Source: Cambridge University Press [March 11, 2019]



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Teenage T. rex was already chomping on prey, new UW Oshkosh research shows

New research from the University of Wisconsin Oshkosh indicates that even as a teenager the Tyrannosaurus rex showed signs that it would grow up to be a ferocious predator.











Teenage T. rex was already chomping on prey, new UW Oshkosh research shows
Joseph Peterson, a vertebrate paleontologist at the University of Wisconsin Oshkosh,
demonstrates how a T. rex takes a bite [Credit: Patrick Flood, UW Oshkosh]

In a study published last week in the peer-reviewed journal Peerj–the Journal of Life and Environmental Sciences, UWO scientists reported evidence that a juvenile T. rex fed on a large plant-eating dinosaur, even though it lacked the bone-crushing abilities it would develop as an adult.


While studying fossils from an Edmontosaurus–a plant-eating Hadrosaurid or duck-billed dinosaur, UWO vertebrate paleontologist Joseph Peterson noticed three large, v-shaped, bite marks on a tail bone and wondered, “Who made these?”


Peterson knew that T. rex–a member of the meat-eating dinosaur suborder known as Theropoda–was “a likely culprit.”


“We suspected that T. rex was responsible for the bit marks, because in the upper Cretaceous rock formation, where the hadrosaur was discovered, there are only a few carnivorous dinosaurs and other reptiles in the fossil record. Crocodile fossils are found there, but such a crocodile would have left tooth marks that are round rather than the elliptical punctures we found on the vertebra,” Peterson explained.











Teenage T. rex was already chomping on prey, new UW Oshkosh research shows
UW Oshkosh researchers made a silicone peel of puncture marks to help
determine their origin [Credit: Patrick Flood, UW Oshkosh]

“There also were small Velociraptor-like dinosaurs, but their teeth are too small to have made the marks. Finally, an adult T. rex would have made punctures that would have been too large! That’s when we started considering a juvenile tyrannosaur.”


To test the hypothesis, Peterson and geology student Karsen Daus, of Suamico, coated the fossil with a silicon rubber to make a silicone peel of the puncture marks.


They found that the dimensions of the “teeth” better matched a late-stage juvenile T. rex (11 to 12 years) than an adult (approximately 30 years).


“Although this T. rex was young, it really packed a punch,” Peterson said.


“This is significant to paleontology because it demonstrates how T. rex–the most popular dinosaur of all time–may have developed changes in diet and feeding abilities while growing,” he said. “This is part of a larger, ongoing research initiative by many paleontologists to better understand how T. rex grew and functioned as a living creature over 65 million years ago.”


Most theropod feeding traces and bite marks are attributed to adults; juvenile tooth marks rarely have been reported in the literature, he added.


“We really are in the ‘Golden Age’ of paleontology,” Peterson said. “We are learning more now than we ever thought we would know about dinosaurs. And, we’re learn more about how they grew up.”


Source: University of Wisconsin Oshkosh [March 11, 2019]



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Fossil teeth from Kenya solve ancient monkey mystery

The teeth of a new fossil monkey, unearthed in the badlands of northwest Kenya, help fill a 6-million-year void in Old World monkey evolution, according to a study by U.S. and Kenyan scientists published in the Proceedings of the National Academy of Sciences.











Fossil teeth from Kenya solve ancient monkey mystery
A fossil jaw of the newly discovered ancient Old World monkey named Alophia. It is dated to 22 million years in age
[Credit: Reproduced with the permission from Proceedings of the National Academy of Sciences]

The discovery of 22-million-year-old fossilized monkey teeth — described as belonging to a new species, Alophia metios — fills a void between a previously discovered 19-million-year-old fossil tooth in Uganda and a 25-million-year-old fossil tooth found in Tanzania. The finding also sheds light on how their diet may have changed the course of their evolution.


“For a group as highly successful as the monkeys of Africa and Asia, it would seem that scientists would have already figured out their evolutionary history,” said the study’s corresponding author John Kappelman, an anthropology and geology professor at The University of Texas at Austin.


“Although the isolated tooth from Tanzania is important for documenting the earliest occurrence of monkeys, the next 6 million years of the group’s existence are one big blank. This new monkey importantly reveals what happened during the group’s later evolution.”


Since the time interval from 19 to 25 million years ago is represented by a small number of African fossil sites, the team targeted the famous fossil-rich region of West Turkana to try to fill in that blank.


“Today, this region is very arid,” said Benson Kyongo, a collections manager at the National Museums of Kenya. “But millions of years ago, it was a forest and woodland landscape crisscrossed by rivers and streams. These ancient monkeys were living the good life.”











Fossil teeth from Kenya solve ancient monkey mystery
Sedimentary rocks exposed in the eroded badlands of Nakwai, Kenya, where the remains of an ancient species
of Old World monkey named Alophia were discovered [Credit: Reproduced with the permission
from Proceedings of the National Academy of Sciences]

While in the field, the team uncovered hundreds of mammal and reptile jaws, limbs and teeth ranging from 21 million to more than 24 million years old, including remains of early elephants. The newly discovered monkey teeth are more primitive than geologically younger monkey fossils, lacking what researchers referred to as “lophs,” or a pair of molar crests, thus earning the new species its name, Alophia, meaning “without lophs.”


“These teeth are so primitive that when we first showed them to other scientists, they told us, “Oh no, that isn’t a monkey. It’s a pig,” said Ellen Miller, an anthropology professor at Wake Forest University. “But because of other dental features, we are able to convince them that yes, it is in fact a monkey.”


The success of Old World monkeys appears to be closely tied to their unique dentition, researchers said. Today, the configuration of cusps and lophs on the molar teeth enable them to process the wide range of plant and animal foods encountered in the diverse environments of Africa and Asia.


“You can think of the modern-day monkey molar as the uber food processor, able to slice, dice, mince and crush all sorts of foods,” said Mercedes Gutierrez, an anatomy professor at the University of Minnesota.











Fossil teeth from Kenya solve ancient monkey mystery
Scientists collecting rock samples for dating the sediments at Nakwai, Kenya, where the Alophia was discovered
[Credit: Reproduced with the permission from Proceedings of the National Academy of Sciences]

“How and when this unique dentition evolved is one of the unanswered questions in primate evolution,” said James Rossie, an anthropology professor at Stony Brook University. The researchers speculated that Alophia’s primitive dentition was adapted to a diet that consisted of hard fruits, seeds and nuts, and not leaves, which are more efficiently processed by the more evolved dentition of fossil monkeys dating from after 19 million years ago.


“It is usually assumed that the trait responsible for a group’s success evolved when the group originated, but Alophia shows us this is not the case for Old World monkeys,” said Samuel Muteti, a researcher at the National Museums of Kenya. “Instead, the characteristic dentition of modern monkeys evolved long after the group first appeared.”


The researchers hypothesized that the inclusion of leaves in the diet is what later drove monkey dental evolution.


Monkeys originated at a time when Africa and Arabia were joined as an island continent, with its animals evolving in isolation until docking with Eurasia sometime between 20 million and 24 million years ago. It was only after docking that the mammals today typically considered “African” – antelope, pigs, lions, rhinos, etc. – made their entry onto the continent. So, researchers asked: Could this event and possible competition between the residents and the newly arrived Eurasian species have driven monkeys to exploit leaves, or did changing climates serve to make leaves a more attractive menu entrée?


“The way to test between these hypotheses is to collect more fossils,” Kappelman said. “Establishing when, exactly, the Eurasian fauna entered Afro-Arabia remains one of the most important questions in paleontology, and West Turkana is one of the only places we know of to find that answer.”


The team intends to be back in the field later this year.


Source: University of Texas at Austin [March 11, 2019]



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Researchers find a piece of Palaeolithic art featuring birds and humans

It is not very common to find representations of scenes instead of individual figures in Palaeolithic art, but it is even harder for these figures to be birds instead of mammals such as goats, deer or horses. So far, historians have only found three scenes of Palaeolithic art featuring humans and birds in Europe.











Researchers find a piece of Palaeolithic art featuring birds and humans
A tracing of the engraved figures over the stone [Credit: University of Barcelona]

Now, an article published in the journal L’Anthropologie tells how University of Barcelona researchers found -in the site of Hort de la Bequera (Margalef de Montsant, Priorat)-, an artistic piece from 12,500 years ago in which humans and birds try to interact in a pictorial scene with exceptional traits: figures seem to star a narration on hunting and motherhood.


Regarding the Catalan context in particular, this is an important finding regarding the few pieces of Palaeolithic art in Catalonia and it places this territory within the stream of artistic production of the upper Palaeolithic in the Mediterranean.


The piece they found is a 30-centimeter long limestone which shows two human figures and two birds, which the researchers identified as cranes. Since they found the piece in 2011, they underwent all cleaning, restoration and 3D copying procedures to study it in detail. Those figures were engraved in the stone board with a flint tool so that they created an organized composition compared to the other pieces of the same period.


“This is one of the few found scenes so far which suggest the birth of a narrative art in Europe, and this theme is unique, since it combines an image of hunting and a motherhood one: a birth with its young one”, says the first signer of the article, ICREA researcher and lecturer at the UB Inés Domingo.



“In the represented scene the birds catch the attention, they are copied or chased by two human figures”, continues Domingo. “We do not know the meaning of the scene for prehistoric peoples, but what it says is that not only they were regarded as preys but also as a symbol for European Palaeolithic societies”, she continues.


“We do not doubt this is an exceptional milestone in European Palaeolithic rock art due its singularity, its excellent conservation and the chances to study it within a general context of excavation”, say the authors of the article; members of the Prehistoric Studies and Research Seminar (SERP).


Apart from Domingo, other signers are the UB lecturers of Prehistory Pilar García Argüelles, Jordi Nadal, directors of the excavation in Host de la Boquera, Professor Josep Maria Fullola, director of SERP, and José L. Lerma and the researcher Miriam Cabrelles, from Universitat Politècnica de València, who worked on the 3D reproduction of this piece.


The other sites in Europe researchers had found so far with human and bird figures are rock paintings in the site of Lascauz, a perforated baton in Abri Mege (Teyjat, Dordogne), and the Great Hunter plaque in the site of Gönnersdorf (Germany).











Researchers find a piece of Palaeolithic art featuring birds and humans
The stone where it was found [Credit: Jordi Nadal]

SERP researchers have been excavating in the valley of Montsant since 1979, an exceptional area regarding findings of this period of the late upper Palaeolithic. In particular, excavations have taken place in Host de la Boquera since 1998 and it provided a great amount of flint tools and structure such as rooms for a fireplace.
The director of the excavation, Pilar García Argüelles notes that “the findings of the engraved scene are exceptional, and proves the importance of the site and the area regarding Palaeolithic art in the peninsular north-east area; where we can find nearby the only Palaeolithic cave engraving in Catalonia, the deer in the cave of Taverna (Margalef de Montsant), and about 40 kilometres away there is Molí del Salt (Vimbodí), with an interesting series of stone blocks with engraved animals and a representation of huts”.


The first to identify the engraving was the co-director of the excavation, Jordi Nadal, who remembers that moment with excitement: “Since the first moment I was aware of the importance of this finding, of its uniqueness; these things do not happen very often, this is seeing a figure that has been forgotten and buried for 12,500 years”.


Source: University of Barcelona [March 11, 2019]



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US to return 361 rare artefacts to China

A green couch of glazed pottery from the Ming Dynasty (1368-1644) and pottery animals with a livestock shed from the Han Dynasty (206 BC-AD 220) are being carefully packed for the trip home to China.











US to return 361 rare artefacts to China
Credit: Zhang Ruinan/China Daily

They were among 361 Chinese relics and artifacts bound for their land of origin shown to the media on Thursday by the US government at the Eiteljorg Museum of American Indians and Western Art in Indianapolis, Indiana.
The items, including stoneware, jade objects, bronze weapons and pottery ranging from the Neolithic Age (10,000-2,000 BC) to the Qing Dynasty (1644-1911), form the largest repatriation of relics from the United States since 2009, when the US and China signed an agreement to enhance such cooperation.











US to return 361 rare artefacts to China
Credit: Zhang Ruinan/China Daily

“The US and China have a long and rewarding history of partnerships across many fronts,” said Kristi Johnson, chief of the FBI’s Transnational Organized Crime section. “Today marks another milestone of this important partnership. … Through a long and effective collaborative effort between the FBI and our partners in China’s National Cultural Heritage Administration, we were able to identify a total of 361 objects that rightfully belong to China,” Johnson said.
Chinese cultural objects lost abroad constitute a significant part of the cultural heritage of China, said Hu Bing, deputy director of the heritage administration.











US to return 361 rare artefacts to China
Credit: Xinhua/Liu Jie

“This repatriation presents the outcome of a continuing effort during five years by China and the US,” Hu said. “It not only demonstrates concerted efforts of China and the US to support and meet each other halfway in the recovery and return of cultural property … but also contributes to mutual understanding and trust between the two peoples.”
Hu said it set an example for ensuring the safety of cultural heritage globally and was an invaluable gift toward the celebration of the 40th anniversary of the establishment of China-US relations.











US to return 361 rare artefacts to China
Credit: Xinhua/Liu Jie

Hu said it also could be a starting point, together with the US, in establishing and improving mechanisms for information sharing about stolen cultural objects, and increasing international exchanges and teamwork against the looting and theft of cultural property.
In a regular news briefing on Friday, Foreign Ministry spokesman Lu Kang expressed the Chinese government’s appreciation for repatriation of the relics by the US. Cooperation in cultural heritage protection is an important part of people-to-people exchanges and China is willing to make joint efforts with the US to further promote cooperation in the field, he said.



Aleisha Woodward, deputy assistant secretary for policy at the US State Department Bureau of Educational and Cultural Affairs, called it “a wonderful opportunity for us to celebrate the cultural heritage that we both respect”.


In 2009, the two nations signed their first agreement on the preservation of cultural heritage. The US has returned two groups of 36 relics and artifacts to China in March 2011 and December 2015.


The 361 objects were among about 7,000 cultural artifacts the FBI seized in Indiana when it raided the home of a 91-year-old ex-missionary named Donald Miller in 2014.


Author: Zhang Ruinan | Source: China Daily [March 05, 2019]



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Mystery anchor found off Cornwall coast may be from world’s most valuable shipwreck

An huge old anchor trawled in Cornwall  may be from one of the most valuable shipwrecks in history.











Mystery anchor found off Cornwall coast may be from world's most valuable shipwreck
Anchor that could be from world’s most valuable shipwreck uncovered
[Credit: Brackan Pearce]

The Merchant Royal, a 17th-century English merchant ship, was lost at sea off Land’s End in September 1641.


It is believed that the ship sank carrying gold, silver and bullion worth hundreds of millions – if not billions – in today’s prices.


The giant anchor was trawled by the fishing vessel Spirited Lady earlier this week, and is estimated to date back to a period between 1600-1800.


The anchor’s size and age have led some to speculate that it may have once belonged to the Merchant Royal.











Mystery anchor found off Cornwall coast may be from world's most valuable shipwreck
A huge anchor, now at Newlyn harbour, was pulled up by local fisherman Brackan Pearce,
 skipper of Spirited Lady III [Credit: Greg Martin/Cornwall Live]

The ship was rumoured to be the wreck found by the US company Odyssey Marine Exploration in 2007 and known only by the codename Black Swan.


But after lengthy legal wranglings, Odyssey was ordered to hand over coins recovered from the wreck to Spain, suggesting that the ship was really a Spanish frigate.


The case became notorious when it popped up in leaked US diplomatic cables released by the WikiLeaks website.


Still, as far as we know, the Merchant Royal – nicknamed “the El Dorado of the seas” – is yet to be discovered.











Mystery anchor found off Cornwall coast may be from world's most valuable shipwreck
Some people have suggested that it may be the anchor from the 17th century ship Merchant Royal,
which sank off Land’s End whilst carrying a cargo of gold
[Credit: Greg Martin/Cornwall Live]

The Telegraph reported in 2007: “Salvage companies have spent years looking for the wreck of Merchant Royal, an English ship known as the “Eldorado of the seas”, which sank in bad weather near the Isles of Scilly in 1641 as it was returning to Dartmouth laden with treasure from Mexico.


“Carrying a crew of 80 under the command of Capt John Limbrey, the ship – owned by a group of London merchants – reportedly had “£300,000 in silver, £100,000 in gold and as much again in jewel” lying in its hold.


“But it was taking on water as it reached the Western Approaches and ran into heavy weather. The loss to the Treasury and the nation was such that proceedings of the House of Commons were interrupted for the news to be broken.”


Author: Shannon Hards | Source: Cornwall Live [March 05, 2019]



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New surprises from Jupiter and Saturn

The latest data sent back by the Juno and Cassini spacecraft from giant gas planets Jupiter and Saturn have challenged a lot of current theories about how planets in our solar system form and behave.











New surprises from Jupiter and Saturn

Credit: NASA, SWRI, MSSS



The detailed magnetic and gravity data have been “invaluable but also confounding,” said David Stevenson from Caltech, who will present an update of both missions this week at the 2019 American Physical Society March Meeting in Boston.


“Although there are puzzles yet to be explained, this is already clarifying some of our ideas about how planets form, how they make magnetic fields and how the winds blow,” Stevenson said.


Cassini orbited Saturn for 13 years before its dramatic final dive into the planet’s interior in 2017, while Juno has been orbiting Jupiter for two and a half years.


Juno’s success as a mission to Jupiter is a tribute to innovative design. Its instruments are powered by solar energy alone and protected so as to withstand the fierce radiation environment.


Stevenson says the inclusion of a microwave sensor on Juno was a good decision.


“Using microwaves to figure out the deep atmosphere was the right, but unconventional, choice,” he said. The microwave data have surprised the scientists, in particular by showing that the atmosphere is evenly mixed, something conventional theories did not predict.


“Any explanation for this has to be unorthodox,” Stevenson said.


Researchers are exploring weather events concentrating significant amounts of ice, liquids and gas in different parts of the atmosphere as possible explanations, but the matter is far from sealed.


Jupiter’s magnetic field [Credit: Caltech]


Other instruments on board Juno, gravity and magnetic sensors, have also sent back perplexing data. The magnetic field has spots (regions of anomalously high or low magnetic field) and also a striking difference between the northern and southern hemispheres.


“It’s unlike anything we have seen before,” Stevenson said.


The gravity data have confirmed that in the midst of Jupiter, which is at least 90 percent hydrogen and helium by mass, there are heavier elements amounting to more than 10 times the mass of Earth. However, they are not concentrated in a core but are mixed in with the hydrogen above, most of which is in the form of a metallic liquid.


The data has provided rich information about the outer parts of both Jupiter and Saturn. The abundance of heavier elements in these regions is still uncertain, but the outer layers play a larger-than-expected role in the generation of the two planets’ magnetic fields. Experiments mimicking the gas planets’ pressures and temperatures are now needed to help the scientists understand the processes that are going on.


For Stevenson, who has studied gas giants for 40 years, the puzzles are the hallmark of a good mission.


“A successful mission is one that surprises us. Science would be boring if it merely confirmed what we previously thought,” he said.


Source: American Physical Society [March 06, 2019]




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Chances for life expand when passing stars push binaries together

Planetary systems can be harsh environments in their early history. The young worlds orbit suns in stellar nurseries, clusters of stars where violent encounters are commonplace. None of this makes it easy for life to get going, but now astronomers at the University of Sheffield find one positive of this tumultuous period. A model developed by undergraduate student Bethany Wootton and Royal Society Dorothy Hodgkin Fellow Dr Richard Parker looks at how the habitable zone – the region around a star where the temperature allows liquid water to exist – changes around pairs of stars, so-called binary systems.











Chances for life expand when passing stars push binaries together
Artist’s impression of life on a planet in orbit around a binary star system, visible as two suns in the sky
[Credit: Mark Garlick]

The two scientists discovered that an encounter with a passing third star may squeeze the binary pair together, expanding the habitable zone in the process. Their results appear in a new paper in the journal Monthly Notices of the Royal Astronomical Society.
The habitable zone, sometimes called the ‘Goldilocks zone’ as the temperature is not too hot and not too cold, is thought to be essential for the development of life on a planet. If a planet lies outside this zone, then the formation of the complex molecules needed for life is less likely to happen.


Around one third of stellar systems in our galaxy are thought to be made up of two or more stars, and this fraction is much higher when stars are young. If these stars are a relatively large distance apart, the size of the Goldilocks zone around each star is governed by the radiation from the individual star. If the two stars are closer, the size of the Goldilocks zone increases because each star feels additional warmth from the other and this increases the likelihood of a planet being located in the right place for life to develop.











Chances for life expand when passing stars push binaries together
A NASA graphic showing an Earth-sized planet inside, within, and outside of the habitable zone around a star
[Credit: NASA]

Wootton and Parker looked at how this changed in stellar nurseries. They used computer simulations to model the interactions between young stars in these clusters, calculating how these encounters affected the binary pairs. In a typical stellar nursery with 350 binaries, the two researchers found that 20 would have their stars squeezed together, and their Goldilocks zones then expanded.
In a few cases, the habitable zones of widely separated stars actually overlapped, further increasing the prospect of any planets in orbit around one or both of the stars being in the right place for life to develop.


Wootton comments: “The search for life elsewhere in the universe is one of the most fundamental questions in modern science, and we need every bit of evidence we can find to help answer it.”











Chances for life expand when passing stars push binaries together
A diagram of two stars in a binary system, before and after an encounter with a third passing star. The stars are the
 yellow/orange dots (the yellow star is the same mass as our Sun, the orange star is just over half of the Sun’s mass) and
 the habitable zones are shown in blue. The ‘narrow’ habitable zone is the most pessimistic estimate for where water
can exist as a liquid, and the cyan habitable zone is the most optimistic estimate. The diagram shows one star in an orbit,
following the black path, around the other, and the size and shape of the orbit changes after the encounter. In this encounter
 the two stars have moved closer together, and both stars feel the extra warmth from each other. This has the effect of
increasing the size of the habitable zones, especially around the lower mass star, and sometimes the habitable zones
overlap. The grey dashed line shows the maximum distance a planet can be from the star and still remain
on a stable orbit [Credit: Richard Parker/Bethany Wootton/University of Sheffield]

“Our model suggests that there are more binary systems where planets sit in Goldilocks zones than we thought, increasing the prospects for life. So those worlds beloved of science fiction writers – where two suns shine in their skies above alien life – look a lot more likely now.”


The next steps for this research are to use more computer models to understand whether the negative processes a young star experiences are outweighed by the positives. Parker and his research team are currently exploring whether internal heating within the Earth happens because our young Sun was born close to a supernova explosion of a massive star; this explosion would be catastrophic for life on Earth today, but may provide the necessary conditions for life to have developed on Earth in the first place.


Source: Royal Astronomical Society [March 06, 2019]



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