Galápagos islands have nearly 10 times more alien marine species than once thought

The bryozoan Amathia verticillata. Known in other parts of the world for fouling pipes and fishing gear and killing seagrasses, its discovery in the Galapagos is especially concerning for scientists.

Over 50 non-native species have found their way to the Galápagos Islands, almost 10 times more than scientists previously thought, reports a new study in Aquatic Invasions published Thursday, March 28.

The study, a joint effort of the Smithsonian Environmental Research Center, Williams College, and the Charles Darwin Foundation, documents 53 species of introduced marine animals in this UNESCO World Heritage Site, one of the largest marine protected areas on Earth. Before this study came out, scientists knew about only five.

"This increase in alien species is a stunning discovery, especially since only a small fraction of the Galápagos Islands was examined in this initial study," said Greg Ruiz, a co-author and marine biologist with the Smithsonian Environmental Research Center.

"This is the greatest reported increase in the recognition of alien species for any tropical marine region in the world," said lead author James Carlton, an emeritus professor of the Maritime Studies Program of Williams College-Mystic Seaport.

The Galápagos lie in the equatorial Pacific, roughly 600 miles west of Ecuador. Made famous by Charles Darwin's visit in 1835, the islands have long been recognized for their remarkable biodiversity. But with their fame, traffic has spiked. In 1938, just over 700 people lived on the Galápagos. Today, more than 25,000 people live on the islands, and nearly a quarter-million tourists visit each year.

Carlton and Ruiz began their study in 2015, with Inti Keith of the Charles Darwin Foundation. They conducted field surveys on two of the larger Galápagos Islands: Santa Cruz and Baltra, where they hung settlement plates from docks one meter underwater to see what species would grow on them. They also collected samples from mangrove roots, floating docks and other debris and scoured the literature for previous records of marine species on the islands.

The team documented 48 additional non-native species in the Galápagos. Most of them (30) were new discoveries that could have survived on the islands for decades under the radar. Another 17 were species scientists already knew lived on the Galápagos but previously thought were native. One final species, the bryozoan Watersipora subtorquata, was collected in 1987 but not identified until now.

Sea squirts, marine worms and moss animals (bryozoans) made up the majority of the non-native species. Almost all of the non-natives likely arrived inadvertently in ships from tropical seas around the world. Some of the most concerning discoveries include the bryozoan Amathia verticillata -- known for fouling pipes and fishing gear and killing seagrasses -- and the date mussel Leiosolenus aristatus, which researchers have already seen boring into Galápagos corals.

"This discovery resets how we think about what's natural in the ocean around the Galápagos, and what the impacts may be on these high-value conservation areas," Carlton said.

To reduce future invasions, the Galápagos already have one of the most stringent biosecurity programs in the world. International vessels entering the Galápagos Marine Reserve may anchor in only one of the main ports, where divers inspect the vessel. If the divers find any non-native species, the vessel is requested to leave and have its hull cleaned before returning for a second inspection.

Read more at Science Daily

66-million-year-old deathbed linked to dinosaur-killing meteor

Fossilized fish piled one atop another, suggesting that they were flung ashore and died stranded together on a sand bar after the wave from the seiche withdrew.

The beginning of the end started with violent shaking that raised giant waves in the waters of an inland sea in what is now North Dakota.

Then, tiny glass beads began to fall like birdshot from the heavens. The rain of glass was so heavy it may have set fire to much of the vegetation on land. In the water, fish struggled to breathe as the beads clogged their gills.

The heaving sea turned into a 30-foot wall of water when it reached the mouth of a river, tossing hundreds, if not thousands, of fresh-water fish -- sturgeon and paddlefish -- onto a sand bar and temporarily reversing the flow of the river. Stranded by the receding water, the fish were pelted by glass beads up to 5 millimeters in diameter, some burying themselves inches deep in the mud. The torrent of rocks, like fine sand, and small glass beads continued for another 10 to 20 minutes before a second large wave inundated the shore and covered the fish with gravel, sand and fine sediment, sealing them from the world for 66 million years.

This unique, fossilized graveyard -- fish stacked one atop another and mixed in with burned tree trunks, conifer branches, dead mammals, mosasaur bones, insects, the partial carcass of a Triceratops, marine microorganisms called dinoflagellates and snail-like marine cephalopods called ammonites -- was unearthed by paleontologist Robert DePalma over the past six years in the Hell Creek Formation, not far from Bowman, North Dakota. The evidence confirms a suspicion that nagged at DePalma in his first digging season during the summer of 2013 -- that this was a killing field laid down soon after the asteroid impact that eventually led to the extinction of all ground-dwelling dinosaurs. The impact at the end of the Cretaceous Period, the so-called K-T boundary, exterminated 75 percent of life on Earth.

"This is the first mass death assemblage of large organisms anyone has found associated with the K-T boundary," said DePalma, curator of paleontology at the Palm Beach Museum of Natural History in Florida and a doctoral student at the University of Kansas. "At no other K-T boundary section on Earth can you find such a collection consisting of a large number of species representing different ages of organisms and different stages of life, all of which died at the same time, on the same day."

In a paper to appear next week in the journal Proceedings of the National Academy of Sciences, he and his American and European colleagues, including two University of California, Berkeley, geologists, describe the site, dubbed Tanis, and the evidence connecting it with the asteroid or comet strike off Mexico's Yucatan Peninsula 66 million years ago. That impact created a huge crater, called Chicxulub, in the ocean floor and sent vaporized rock and cubic miles of asteroid dust into the atmosphere. The cloud eventually enveloped Earth, setting the stage for Earth's last mass extinction.

"It's like a museum of the end of the Cretaceous in a layer a meter-and-a-half thick," said Mark Richards, a UC Berkeley professor emeritus of earth and planetary science who is now provost and professor of earth and space sciences at the University of Washington.

Richards and Walter Alvarez, a UC Berkeley Professor of the Graduate School who 40 years ago first hypothesized that a comet or asteroid impact caused the mass extinction, were called in by DePalma and Dutch scientist Jan Smit to consult on the rain of glass beads and the tsunami-like waves that buried and preserved the fish. The beads, called tektites, formed in the atmosphere from rock melted by the impact.

Tsunami vs. seiche

Richards and Alvarez determined that the fish could not have been stranded and then buried by a typical tsunami, a single wave that would have reached this previously unknown arm of the Western Interior Seaway no less than 10 to 12 hours after the impact 3,000 kilometers away, if it didn't peter out before then. Their reasoning: The tektites would have rained down within 45 minutes to an hour of the impact, unable to create mudholes if the seabed had not already been exposed.

Instead, they argue, seismic waves likely arrived within 10 minutes of the impact from what would have been the equivalent of a magnitude 10 or 11 earthquake, creating a seiche (pronounced saysh), a standing wave, in the inland sea that is similar to water sloshing in a bathtub during an earthquake. Though large earthquakes often generate seiches in enclosed bodies of water, they're seldom noticed, Richards said. The 2011 Tohoku quake in Japan, a magnitude 9.0, created six-foot-high seiches 30 minutes later in a Norwegian fjord 8,000 kilometers away.

"The seismic waves start arising within nine to 10 minutes of the impact, so they had a chance to get the water sloshing before all the spherules (small spheres) had fallen out of the sky," Richards said. "These spherules coming in cratered the surface, making funnels -- you can see the deformed layers in what used to be soft mud -- and then rubble covered the spherules. No one has seen these funnels before."

The tektites would have come in on a ballistic trajectory from space, reaching terminal velocities of between 100 and 200 miles per hour, according to Alvarez, who estimated their travel time decades ago.

"You can imagine standing there being pelted by these glass spherules. They could have killed you," Richards said. Many believe that the rain of debris was so intense that the energy ignited wildfires over the entire American continent, if not around the world.

"Tsunamis from the Chicxulub impact are certainly well-documented, but no one knew how far something like that would go into an inland sea," DePalma said. "When Mark came aboard, he discovered a remarkable artifact -- that the incoming seismic waves from the impact site would have arrived at just about the same time as the atmospheric travel time of the ejecta. That was our big breakthrough."

At least two huge seiches inundated the land, perhaps 20 minutes apart, leaving six feet of deposits covering the fossils. Overlaying this is a layer of clay rich in iridium, a metal rare on Earth, but common in asteroids and comets. This layer is known as the K-T, or K-Pg boundary, marking the end of the Cretaceous Period and the beginning of the Tertiary Period, or Paleogene.

Iridium

In 1979, Alvarez and his father, Nobelist Luis Alvarez of UC Berkeley, were the first to recognize the significance of iridium that is found in 66 million-year-old rock layers around the world. They proposed that a comet or asteroid impact was responsible for both the iridium at the K-T boundary and the mass extinction.

The impact would have melted the bedrock under the seafloor and pulverized the asteroid, sending dust and melted rock into the stratosphere, where winds would have carried them around the planet and blotted out the sun for months, if not years. Debris would have rained down from the sky: not only tektites, but also rock debris from the continental crust, including shocked quartz, whose crystal structure was deformed by the impact.

The iridium-rich dust from the pulverized meteor would have been the last to fall out of the atmosphere after the impact, capping off the Cretaceous.

"When we proposed the impact hypothesis to explain the great extinction, it was based just on finding an anomalous concentration of iridium -- the fingerprint of an asteroid or comet," said Alvarez. "Since then, the evidence has gradually built up. But it never crossed my mind that we would find a deathbed like this."

Key confirmation of the meteor hypothesis was the discovery of a buried impact crater, Chicxulub, in the Caribbean and off the coast of the Yucatan in Mexico, that was dated to exactly the age of the extinction. Shocked quartz and glass spherules were also found in K-Pg layers worldwide. The new discovery at Tanis is the first time the debris produced in the impact was found along with animals killed in the immediate aftermath of the impact.

"And now we have this magnificent and completely unexpected site that Robert DePalma is excavating in North Dakota, which is so rich in detailed information about what happened as a result of the impact," Alvarez said. "For me, it is very exciting and gratifying!"

Tektites

Jan Smit, a retired professor of sedimentary geology from Vrije Universiteit in Amsterdam in The Netherlands who is considered the world expert on tektites from the impact, joined DePalma to analyze and date the tektites from the Tanis site. Many were found in near perfect condition embedded in amber, which at the time was pliable pine pitch.

"I went to the site in 2015 and, in front of my eyes, he (DePalma) uncovered a charred log or tree trunk about four meters long which was covered in amber, which acted as sort of an aerogel and caught the tektites when they were coming down," Smit said. "It was a major discovery, because the resin, the amber, covered the tektites completely, and they are the most unaltered tektites I have seen so far, not 1 percent of alteration. We dated them, and they came out to be exactly from the K-T boundary."

The tektites in the fishes' gills are also a first.

"Paddlefish swim through the water with their mouths open, gaping, and in this net, they catch tiny particles, food particles, in their gill rakers, and then they swallow, like a whale shark or a baleen whale," Smit said. "They also caught tektites. That by itself is an amazing fact. That means that the first direct victims of the impact are these accumulations of fishes."

Smit also noted that the buried body of a Triceratops and a duck-billed hadrosaur proves beyond a doubt that dinosaurs were still alive at the time of the impact.

"We have an amazing array of discoveries which will prove in the future to be even more valuable," Smit said. "We have fantastic deposits that need to be studied from all different viewpoints. And I think we can unravel the sequence of incoming ejecta from the Chicxulub impact in great detail, which we would never have been able to do with all the other deposits around the Gulf of Mexico."

Read more at Science Daily

Researchers discover the source of new neurons in brain's hippocampus

The dentate gyrus of mouse hippocampus at postnatal day 7, blue is nuclei marker, green is progeny of HOPX-expressing progenitor cells, and red is marker of cell proliferation.

It was once believed that mammals were born with the entire supply of neurons they would have for a lifetime. However, over the past few decades, neuroscientists have found that at least two brain regions -- the centers of the sense of smell and the hippocampus, the seat of learning and memory -- grow new neurons throughout life.

Researchers from the Perelman School of Medicine at the University of Pennsylvania have shown, in mice, that one type of stem cell that makes adult neurons is the source of this lifetime stock of new cells in the hippocampus. Published this week in Cell, these findings may help neuroscientists figure out how to maintain youthful conditions for learning and memory, and repair and regenerate parts of the brain after injury and aging.

"We've shown for the first time, in mammals, that neurons in the dentate gyrus of the hippocampus grow and develop from a single population of stem cells, over an entire lifespan," said senior author Hongjun Song, PhD a professor of Neuroscience. "The new immature neurons are more flexible in making connections in the hippocampus compared to mature neurons, which is paramount for healthy learning, memory, and adjusting mood."

The researchers showed that the neural stem cells they found had a common molecular signature across the lifespan of the mice. They did this by labeling neural stem cells in embryos when the brain was still developing and following the cells from birth into adulthood. This approach revealed that new neural stem cells with their precursor's label were continuously making neurons throughout an animal's lifetime.

"This process is unique in the brain," said co-senior author Guo-li Ming, MD, PhD, a professor of Neuroscience. "In the hippocampus, these cells never stop replicating and contribute to the flexibility of the brain in mammals."

This capacity is called plasticity, which is the brain's ability to form new connections throughout life to compensate for injury and disease and to adjust in response to new input from the environment. Ming likens the process of new neuron growth in the hippocampus to adding new units into the circuitry of the brain's motherboard.

Read more at Science Daily

Five new frog species from Madagascar

An adult male Mini scule resting on a fingertip.

Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich and the Bavarian State Collection of Zoology have named five new species of frogs found across the island of Madagascar. The largest could sit on your thumbnail, the smallest is hardly longer than a grain of rice.

Madagascar, an island a little larger than mainland France, has more than 350 frog species. This number of recognized species is constantly rising, and many of the newly named species are very small.

Mark D. Scherz, a PhD candidate at LMU Munich, and Dr. Frank Glaw, Head of the Herpetology Section at the Bavarian State Collection of Zoology in Munich, together with colleagues at the Technical University of Braunschweig and the University of Antananarivo have named five new species of tiny frogs found across the island. Their study appears in the online journal PLOS ONE.

The five new species belong to a group of frogs commonly referred to as 'narrow-mouthed' frogs, a highly diverse family found on every continent except Antarctica and Europe. Although most narrow-mouthed frogs are small to moderately large, many are tiny. In fact, the group includes the smallest frog in the world -- Paedophryne amauensis from Papua New Guinea, mature specimens of which reach a length of only 7.7 mm. What's remarkable is that, in the smallest frogs, "miniaturization" has evolved independently -- often several times within a single region, as highlighted in this new study. Three of the new species belong to a group that is wholly new to science, which the authors have formally dubbed Mini. The other two new species, Rhombophryne proportionalis and Anodonthyla eximia, are also just 11-12 mm long, and are much smaller than their closest relatives.

"When frogs evolve small body size, they start to look remarkably similar, so it is easy to underestimate how diverse they really are," says Mark D. Scherz, lead author on the new study. "Our new genus name, Mini, says it all. Adults of the two smallest species Mini mum and Mini scule are 8-11 mm long, and even the largest member of the genus, Miniature, at 15 mm, could sit on your thumbnail with room to spare."

Finding tiny frogs in the leaf litter is hard work. "Calling males often sit one or two leaves deep and stop calling at the slightest disturbance," says Frank Glaw. "It can take a lot of patience to find the frog you are looking for."

From Science Daily

Saturn's rings coat tiny moons

This graphic shows the ring moons inspected by NASA's Cassini spacecraft in super-close flybys. The rings and moons depicted are not to scale.

New findings have emerged about five tiny moons nestled in and near Saturn's rings. The closest-ever flybys by NASA's Cassini spacecraft reveal that the surfaces of these unusual moons are covered with material from the planet's rings -- and from icy particles blasting out of Saturn's larger moon Enceladus. The work paints a picture of the competing processes shaping these mini-moons.

"The daring, close flybys of these odd little moons let us peer into how they interact with Saturn's rings," said Bonnie Buratti of NASA's Jet Propulsion Laboratory in Pasadena, California. Buratti led a team of 35 co-authors that published their work in the journal Science on March 28. "We're seeing more evidence of how extremely active and dynamic the Saturn ring and moon system is."

The new research, from data gathered by six of Cassini's instruments before its mission ended in 2017, is a clear confirmation that dust and ice from the rings accretes onto the moons embedded within and near the rings.

Scientists also found the moon surfaces to be highly porous, further confirming that they were formed in multiple stages as ring material settled onto denser cores that might be remnants of a larger object that broke apart. The porosity also helps explain their shape: Rather than being spherical, they are blobby and ravioli-like, with material stuck around their equators.

"We found these moons are scooping up particles of ice and dust from the rings to form the little skirts around their equators," Buratti said. "A denser body would be more ball-shaped because gravity would pull the material in."

"Perhaps this process is going on throughout the rings, and the largest ring particles are also accreting ring material around them. Detailed views of these tiny ring moons may tell us more about the behavior of the ring particles themselves," said Cassini Project Scientist Linda Spilker, also at JPL.

Of the satellites studied, the surfaces of those closest to Saturn -- Daphnis and Pan -- are the most altered by ring materials. The surfaces of the moons Atlas, Prometheus and Pandora, farther out from Saturn, have ring material as well -- but they're also coated with the bright icy particles and water vapor from the plume spraying out of Enceladus. (A broad outer ring of Saturn, known as the E ring, is formed by the icy material that fans out from Enceladus' plume.)

The key puzzle piece was a data set from Cassini's Visible and Infrared Mapping Spectrometer (VIMS), which collected light visible to the human eye and also infrared light of longer wavelengths. It was the first time Cassini was close enough to create a spectral map of the surface of the innermost moon Pan. By analyzing the spectra, VIMS was able to learn about the composition of materials on all five moons.

VIMS saw that the ring moons closest to Saturn appear the reddest, similar to the color of the main rings. Scientists don't yet know the exact composition of the material that appears red, but they believe it's likely a mix of organics and iron.

The moons just outside the main rings, on the other hand, appear more blue, similar to the light from Enceladus' icy plumes.

The six uber-close flybys of the ring moons, performed between December 2016 and April 2017, engaged all of Cassini's optical remote sensing instruments that study the electromagnetic spectrum. They worked alongside the instruments that examined the dust, plasma and magnetic fields and how those elements interact with the moons.

Questions remain, including what triggered the moons to form. Scientists will use the new data to model scenarios and could apply the insights to small moons around other planets and possibly even to asteroids.

Read more at Science Daily

Deep groundwater may generate surface streams on Mars

Recurrent Slope Linae on the Palikir Crater walls on Mars.

In mid-2018, researchers supported by the Italian Space Agency detected the presence of a deep-water lake on Mars under its south polar ice caps. Now, researchers at the USC Arid Climate and Water Research Center (AWARE) have published a study that suggests deep groundwater could still be active on Mars and could originate surface streams in some near-equatorial areas on Mars.

The researchers at USC have determined that groundwater likely exists in a broader geographical area than just the poles of Mars and that there is an active system, as deep as 750 meters, from which groundwater comes to the surface through cracks in the specific craters they analyzed.

Heggy, who is a member of the Mars Express Sounding radar experiment MARSIS probing Mars subsurface, and co-author Abotalib Z. Abotalib, a postdoctoral research associate at USC, studied the characteristics of Mars Recurrent Slope Linea, which are akin to dried, short streams of water that appear on some crater walls on Mars.

Scientists previously thought these features were affiliated with surface water flow or close subsurface water flow, says Heggy.

"We suggest that this may not be true. We propose an alternative hypothesis that they originate from a deep pressurized groundwater source which comes to the surface moving upward along ground cracks," Heggy says.

"The experience we gained from our research in desert hydrology was the cornerstone in reaching this conclusion. We have seen the same mechanisms in the North African Sahara and in the Arabian Peninsula, and it helped us explore the same mechanism on Mars," said Abotalib Z. Abotalib, the paper's first author.

The two scientists concluded that fractures within some of Mars' craters, enabled water springs to rise up to the surface as a result of pressure deep below. These springs leaked onto the surface, generating the sharp and distinct linear features found on the walls of these craters. The scientists also provide an explanation on how these water features fluctuate with seasonality on Mars.

The study, to be published on March 28, 2018, in Nature Geoscience, suggests that groundwater might be deeper than previously thought in areas where such streams are observed on Mars. The findings suggest that the exposed part of these ground fractures associated with these springs as the primary location candidates to explore Mars' habitability. Their work suggests that new probing methods should be developed to study these fractures.

Method:

Previous research to explore groundwater on Mars relied on interpreting the returned electromagnetic echoes sent from the radar-probing experiments from orbit onboard Mars Express and Mars Reconnaissance Orbiter. These experiments measured the reflection of the waves from both the surface and the subsurface whenever penetration was possible. However, this earlier method did not yet provide evidence of groundwater occurrence beyond the 2018 South Pole detection.

The authors of this current Nature Geoscience study used hi-resolution optical images and modeling to study the walls of large impact craters on Mars. The goal was to correlate the presence of fractures with the sources of streams that generate short water flows.

Heggy and Abotalib, who have long studied subsurface aquifers and groundwater flow movement on Earth and in desert environments, found similarities between the groundwater moving mechanisms in the Sahara and on Mars.

"Groundwater is strong evidence for the past similarity between Mars and Earth -- it suggest they have a similar evolution, to some extent," says Heggy.

He says this deep source of groundwater is the most convincing evidence of similarities between the two planets -- it suggest both may have had wet periods long enough to create such an active groundwater system.

For Heggy, an advocate for water science and water science education in arid areas, this particular study is not about colonization. But he says these rare and puzzling water flows on Mars are of big interest to the science community.

"Understanding how groundwater has formed on Mars, where it is today and how it is moving helps us constrain ambiguities on the evolution of climatic conditions on Mars for the last three billion years and how these conditions formed this groundwater system. It helps us to understand the similarities to our own planet and if we are going through the same climate evolution and the same path that Mars is going. Understanding Mars' evolution is crucial for understanding our own Earth's long-term evolution and groundwater is a key element in this process. "

Read more at Science Daily

Arctic warming contributes to drought

Icebergs float on Jokulsarlon glacier lagoon at sunrise, in Iceland.

When the Arctic warmed after the ice age 10,000 years ago, it created perfect conditions for drought.

According to new research led by a University of Wyoming scientist, similar changes could be in store today because a warming Arctic weakens the temperature difference between the tropics and the poles. This, in turn, results in less precipitation, weaker cyclones and weaker mid-latitude westerly wind flow -- a recipe for prolonged drought.

The temperature difference between the tropics and the poles drives a lot of weather. When those opposite temperatures are wider, the result is more precipitation, stronger cyclones and more robust wind flow. However, due to the Arctic ice melting and warming up the poles, those disparate temperatures are becoming closer.

"Our analysis shows that, when the Arctic is warmer, the jet stream and other wind patterns tend to be weaker," says Bryan Shuman, a UW professor in the Department of Geology and Geophysics. "The temperature difference in the Arctic and the tropics is less steep. The change brings less precipitation to the mid-latitudes."

Shuman is a co-author of a new study that is highlighted in a paper, titled "Mid-Latitude Net Precipitation Decreased With Arctic Warming During the Holocene," published today (March 27) online in Nature, an international weekly science journal. The print version of the article will be published April 4.

Researchers from Northern Arizona University; Universite Catholique de Louvain in Louvain-In-Neuve, Belgium; the Florence Bascom Geoscience Center in Reston, Va.; and Cornell University also contributed to the paper.

"The Nature paper takes a global approach and relates the history of severe dry periods of temperature changes. Importantly, when temperatures have changed in similar ways to today (warming of the Arctic), the mid-latitudes -- particularly places like Wyoming and other parts of central North America -- dried out," Shuman explains. "Climate models anticipate similar changes in the future."

Currently, the northern high latitudes are warming at rates that are double the global average. This will decrease the equator-to-pole temperature gradient to values comparable with the early to middle Holocene Period, according to the paper.

Shuman says his research contribution, using geological evidence, was helping to estimate how dry conditions have been in the past 10,000 years. His research included three water bodies in Wyoming: Lake of the Woods, located above Dubois; Little Windy Hill Pond in the Snowy Range; and Rainbow Lake in the Beartooth Mountains.

"Lakes are these natural recorders of wet and dry conditions," Shuman says. "When lakes rise or lower, it leaves geological evidence behind."

The researchers' Holocene temperature analysis included 236 records from 219 sites. During the past 10,000 years, many of the lakes studied were lower earlier in history than today, Shuman says.

"Wyoming had several thousand years where a number of lakes dried up, and sand dunes were active where they now have vegetation," Shuman says. "Expanding to the East Coast, it is a wet landscape today. But 10,000 years ago, the East Coast was nearly as dry as the Great Plains."

The research group looked at the evolution of the tropic-to-pole temperature difference from three time periods: 100 years ago, 2,000 years ago and 10,000 years ago. For the last 100 years, many atmospheric records facilitated the analysis but, for the past 2,000 years or 10,000 years, there were fewer records available. Tree rings can help to expand studies to measure temperatures over the past 2,000 years, but lake deposits, cave deposits and glacier ice were studied to record prior temperatures and precipitation.

"This information creates a test for climate models," Shuman says. "If you want to use a computer to make a forecast of the future, then it's useful to test that computer's ability to make a forecast for some other time period. The geological evidence provides an excellent test."

Read more at Science Daily

Fur discoveries in Iron Age graves testify to respect for animals

A microscopic image of deer fur found in a burial site used at the end of the Iron Age (800-1200 CE) in Vilusenharju, Tampere, central Finland.

The doctoral dissertation of Tuija Kirkinen, MA, examines the use and significance of furs in Finland and the region of Karelia surrendered to the Soviet Union. Furs were commonly used in burials in southern Finland until the 14th and 15th century, and in northern Finland as late as the 17th century. The most prevalent group of skins are those of large mammals, which were wrapped around the deceased. In cremation, bear skins were particularly popular, while Finnish forest reindeer and elk skin were commonly used in burials.

Clothes and objects were also manufactured from fur; a knife sheath could be covered or lined with fur.

Finland's oldest goat observation dates back to the Stone Age

As research material, Kirkinen used hair and fur remains found in burial sites, as well as predator claws which had been attached to the skins.

"Contrary to initial assumptions, quite a lot of fur remains have been preserved in graves."

Animal hairs have been identified by their structure with the help of a microscope. Exceptionally, microscopically small hairs have been preserved in connection with other objects and even in the soil of a burial site dating back to the Stone Age (2800-2300 BCE). This finding, made in Perttulanmäki, Kauhava, western Finland, turned out to be Finland's oldest goat finding. As a result, Kirkinen's research provides recommendations for the handling of potential fibre material at archaeological excavations.

According to Kirkinen, Finland has presumably been situated at the intersection of two fur and bear traditions, one based in the west, the other in the east and north. Deer hunted for their meat stand out from the dataset, an aspect where Finnish data clearly differs from material found across Scandinavia. Fewer products made of mustelids and other more typical fur animals have been found, which makes Kirkinen think that fur use related to status was not very common in Finland and the Karelian Peninsula.

The treatment of prey speaks of respect

Archaeological basic research increases our understanding of the past. The research carried out by Tuija Kirkinen opens perspectives on the relationship between humans and animals, particularly animals that serve as the origin of products used by humans.

"Wrapping bodies in fur is a tradition born already among hunting cultures. The continuation of this tradition all the way to early recorded history and, in Lapland, up to the 17th century, speaks of the preservation of a spiritual culture connected with hunting."

Wrapping the deceased in fur made it possible for them to join their ancestors, making the boundary between humans and animals less clear-cut than today. Ethnographic datasets also contain examples of narratives on how fur had to be handled with respect when sewing, or the animals would no longer give their skins up for humans to use.

"This is a distinct difference from modern fur farming," Kirkinen points out.

Read more at Science Daily

Data flows from NASA's TESS Mission, leads to discovery of Saturn-sized planet

A "hot Saturn" passes in front of its host star in this illustration. Astronomers who study stars used "starquakes" to characterize the star, which provided critical information about the planet.

Astronomers who study stars are providing a valuable assist to the planet-hunting astronomers pursuing the primary objective of NASA's new TESS Mission.

In fact, asteroseismologists -- stellar astronomers who study seismic waves (or "starquakes") in stars that appear as changes in brightness -- often provide critical information for finding the properties of newly discovered planets.

This teamwork enabled the discovery and characterization of the first planet identified by TESS for which the oscillations of its host star can be measured.

The planet -- TOI 197.01 (TOI is short for "TESS Object of Interest") -- is described as a "hot Saturn" in a recently accepted scientific paper. That's because the planet is about the same size as Saturn and is also very close to its star, completing an orbit in just 14 days, and therefore very hot.

The Astronomical Journal will publish the paper written by an international team of 141 astronomers. Daniel Huber, an assistant astronomer at the University of Hawaii at Manoa's Institute for Astronomy, is the lead author of the paper. Steve Kawaler, a professor of physics and astronomy; and Miles Lucas, an undergraduate student, are co-authors from Iowa State University.

"This is the first bucketful of water from the firehose of data we're getting from TESS," Kawaler said.

TESS -- the Transiting Exoplanet Survey Satellite, led by astrophysicists from the Massachusetts Institute of Technology -- launched from Florida's Cape Canaveral Air Force Station on April 18, 2018. The spacecraft's primary mission is to find exoplanets, planets beyond our solar system. The spacecraft's four cameras are taking nearly month-long looks at 26 vertical strips of the sky -- first over the southern hemisphere and then over the northern. After two years, TESS will have scanned 85 percent of the sky.

Astronomers (and their computers) sort through the images, looking for transits, the tiny dips in a star's light caused by an orbiting planet passing in front of it. NASA's Kepler Mission -- a predecessor to TESS -- looked for planets in the same way, but scanned a narrow slice of the Milky Way galaxy and focused on distant stars.

TESS is targeting bright, nearby stars, allowing astronomers to follow up on its discoveries using other space and ground observations to further study and characterize stars and planets. In another paper recently published online by The Astrophysical Journal Supplement Series, astronomers from the TESS Asteroseismic Science Consortium (TASC) identified a target list of sun-like oscillating stars (many that are similar to our future sun) to be studied using TESS data -- a list featuring 25,000 stars.

Kawaler -- who witnessed the launch of Kepler in 2009, and was in Florida for the launch of TESS (but a last-minute delay meant he had to miss liftoff to return to Ames to teach) -- is on the seven-member TASC Board. The group is led by Jørgen Christensen-Dalsgaard of Aarhus University in Denmark.

TASC astronomers use asteroseismic modeling to determine a host star's radius, mass and age. That data can be combined with other observations and measurements to determine the properties of orbiting planets.

In the case of host star TOI-197, the asteroseismolgists used its oscillations to determine it's about 5 billion years old and is a little heavier and larger than the sun. They also determined that planet TOI-197.01 is a gas planet with a radius about nine times the Earth's, making it roughly the size of Saturn. It's also 1/13th the density of Earth and about 60 times the mass of Earth.

Those findings say a lot about the TESS work ahead: "TOI-197 provides a first glimpse at the strong potential of TESS to characterize exoplanets using asteroseismology," the astronomers wrote in their paper.

Kawaler is expecting that the flood of data coming from TESS will also contain some scientific surprises.

Read more at Science Daily

Hubble watches spun-up asteroid coming apart

This Hubble Space Telescope image reveals the gradual self-destruction of an asteroid, whose ejected dusty material has formed two long, thin, comet-like tails. The longer tail stretches more than 500,000 miles (800,000 kilometers) and is roughly 3,000 miles (4,800 kilometers) wide. The shorter tail is about a quarter as long. The streamers will eventually disperse into space.

A small asteroid has been caught in the process of spinning so fast it's throwing off material, according to new data from NASA's Hubble Space Telescope and other observatories.

Images from Hubble show two narrow, comet-like tails of dusty debris streaming from the asteroid (6478) Gault. Each tail represents an episode in which the asteroid gently shed its material -- key evidence that Gault is beginning to come apart.

Discovered in 1988, the 2.5-mile-wide (4-kilometer-wide) asteroid has been observed repeatedly, but the debris tails are the first evidence of disintegration. Gault is located 214 million miles (344 million kilometers) from the Sun. Of the roughly 800,000 known asteroids between Mars and Jupiter, astronomers estimate that this type of event in the asteroid belt is rare, occurring roughly once a year.

Watching an asteroid become unglued gives astronomers the opportunity to study the makeup of these space rocks without sending a spacecraft to sample them.

"We didn't have to go to Gault," explained Olivier Hainaut of the European Southern Observatory in Germany, a member of the Gault observing team. "We just had to look at the image of the streamers, and we can see all of the dust grains well-sorted by size. All the large grains (about the size of sand particles) are close to the object and the smallest grains (about the size of flour grains) are the farthest away because they are being pushed fastest by pressure from sunlight."

Gault is only the second asteroid whose disintegration has been strongly linked to a process known as a YORP effect. (YORP stands for "Yarkovsky-O'Keefe-Radzievskii-Paddack," the names of four scientists who contributed to the concept.) When sunlight heats an asteroid, infrared radiation escaping from its warmed surface carries off angular momentum as well as heat. This process creates a tiny torque that can cause the asteroid to continually spin faster. When the resulting centrifugal force starts to overcome gravity, the asteroid's surface becomes unstable, and landslides may send dust and rubble drifting into space at a couple miles per hour, or the speed of a strolling human. The researchers estimate that Gault could have been slowly spinning up for more than 100 million years.

Piecing together Gault's recent activity is an astronomical forensics investigation involving telescopes and astronomers around the world. All-sky surveys, ground-based telescopes, and space-based facilities like the Hubble Space Telescope pooled their efforts to make this discovery possible.

The initial clue was the fortuitous detection of the first debris tail, observed on Jan. 5, 2019, by the NASA-funded Asteroid Terrestrial-Impact Last Alert System (ATLAS) telescope in Hawaii. The tail also turned up in archival data from December 2018 from ATLAS and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) telescopes in Hawaii. In mid-January, a second shorter tail was spied by the Canada-France-Hawaii Telescope in Hawaii and the Isaac Newton Telescope in Spain, as well as by other observers. An analysis of both tails suggests the two dust events occurred around Oct. 28 and Dec. 30, 2018.

Follow-up observations with the William Herschel Telescope and ESA's (European Space Agency) Optical Ground Station in La Palma and Tenerife, Spain, and the Himalayan Chandra Telescope in India measured a two-hour rotation period for the object, close to the critical speed at which a loose "rubble-pile" asteroid begins to break up.

"Gault is the best 'smoking gun' example of a fast rotator right at the two-hour limit," said team member Jan Kleyna of the University of Hawaii in Honolulu.

An analysis of the asteroid's surrounding environment by Hubble revealed no signs of more widely distributed debris, which rules out the possibility of a collision with another asteroid causing the outbursts.

The asteroid's narrow streamers suggest that the dust was released in short bursts, lasting anywhere from a few hours to a few days. These sudden events puffed away enough debris to make a "dirt ball" approximately 500 feet (150 meters) across if compacted together. The tails will begin fading away in a few months as the dust disperses into interplanetary space.

Based on observations by the Canada-France-Hawaii Telescope, the astronomers estimate that the longer tail stretches over half a million miles (800,000 kilometers) and is roughly 3,000 miles (4,800 kilometers) wide. The shorter tail is about a quarter as long.

Read more at Science Daily

Lying, sitting or standing: Resting postures determined by animals' size

Hippos lie on their side, but also on their chest.

Why do we never see cows lying on their sides in fields? In ruminants such as cows, sheep, antelopes, deer and giraffes, the bits of food in the stomach that need to be chewed again are sorted using gravity. In order for the process to work smoothly at all times, the stomach has to stay in the same position relative to gravity whether the animal is standing or lying down. That's the reason why cows always lie on their chests and almost never on their sides. It was therefore assumed that animals that digest food in a different way would be more likely to lie on their sides. To investigate the connection between digestive systems and resting postures in more detail, researchers from the University of Zurich observed 250 mammals in zoos in more than 30,000 rest phases.

Large animals rest standing up or lying on their sides

They discovered that their assumption was not quite correct. Alongside other factors, body size influences the animals' resting posture more than digestion type. Small animals with short legs spend a lot of time lying on their chests -- the body shape of such animals, e.g. the rock hyrax, is perfect for this position. "The shorter the distance of the mid-body to the floor, the more likely the animals are to lie down," says Prof. Marcus Clauss of the UZH Clinic for Zoo Animals, Exotic Pets and Wildlife. The larger animals are, the more often they lie completely on their sides, which is more comfortable for the legs of larger animals.

But there are exceptions: Large animals also rest standing up. Horses do this much more often than their nearest relatives, tapirs and rhinoceros. When resting standing up, they "fix" the kneecap in one of their hind legs so that they don't have to tense their muscles. Camelids such as llamas and dromedaries regurgitate some of the contents of their stomachs like ruminants; unlike cows, however, they can sometimes lie on their sides and briefly interrupt the digestive process.

Elephants lie on their sides

Of all the herbivores, elephants lie on their sides the most often. However, older elephants, for whom getting up again is difficult, avoid lying down. "For that reason it's important that mounds of sand are available to elephants in zoos. If they are propped up slightly when lying down, even older animals can get up much more easily," explains Christian Schiffman, the research team's elephant specialist. If the animals don't have this option, they are more likely to lean against walls, pillars or tree trunks.

In contrast to elephants, hippos seem to remain flexible even in old age and lie on their sides. Rodents, it was found, occasionally like to take a break sitting down. The only animal investigated that sometimes rests on its back is the red kangaroo.

From Science Daily

In hunt for life, astronomers identify most promising stars

Artists' concept of the Transiting Exoplanet Survey Satellite against a background of stars and orbiting planets in the Milky Way.

NASA's new Transiting Exoplanet Survey Satellite (TESS) is designed to ferret out habitable exoplanets, but with hundreds of thousands of sunlike and smaller stars in its camera views, which of those stars could host planets like our own?

TESS will observe 400,000 stars across the whole sky to catch a glimpse of a planet transiting across the face of its star, one of the primary methods by which exoplanets are identified.

A team of astronomers from Cornell University, Lehigh University and Vanderbilt University has identified the most promising targets for this search in the new "TESS Habitable Zone Star Catalog," published in Astrophysical Journal Letters. Lead author is Lisa Kaltenegger, professor of astronomy at Cornell, director of Cornell's Carl Sagan Institute and a member of the TESS science team.

The catalog identifies 1,822 stars for which TESS is sensitive enough to spot Earth-like planets just a bit larger than Earth that receive radiation from their star equivalent to what Earth receives from our sun. For 408 stars, TESS can glimpse a planet just as small as Earth, with similar irradiation, in one transit alone.

"Life could exist on all sorts of worlds, but the kind we know can support life is our own, so it makes sense to first look for Earth-like planets," Kaltenegger said. "This catalog is important for TESS because anyone working with the data wants to know around which stars we can find the closest Earth-analogs."

Kaltenegger leads a program on TESS that is observing the catalog's 1,822 stars in detail, looking for planets. "I have 408 new favorite stars," said Kaltenegger. "It is amazing that I don't have to pick just one; I now get to search hundreds of stars."

Confirming an exoplanet has been observed and figuring out the distance between it and its star requires detecting two transits across the star. The 1,822 stars the researchers have identified in the catalog are ones from which TESS could detect two planetary transits during its mission. Those orbital periods place them squarely in the habitable zone of their star.

The habitable zone is the area around a star at which water can be liquid on a rocky planet's surface, therefore considered ideal for sustaining life. As the researchers note, planets outside the habitable zone could certainly harbor life, but it would be extremely difficult to detect any signs of life on such frozen planets without flying there.

The catalog also identifies a subset of 227 stars for which TESS can not only probe for planets that receive the same irradiation as Earth, but for which TESS can also probe out farther, covering the full extent of the habitable zone all the way to cooler Mars-like orbits. This will allow astronomers to probe the diversity of potentially habitable worlds around hundreds of cool stars during the TESS mission's lifetime.

The stars selected for the catalog are bright, cool dwarfs, with temperatures roughly between 2,700 and 5,000 degrees Kelvin. The stars in the catalog are selected due to their brightness; the closest are only approximately 6 light-years from Earth.

"We don't know how many planets TESS will find around the hundreds of stars in our catalog or whether they will be habitable," Kaltenegger said, "but the odds are in our favor. Some studies indicate that there are many rocky planets in the habitable zone of cool stars, like the ones in our catalog. We're excited to see what worlds we'll find."

A total of 137 stars in the catalog are within the continuous viewing zone of NASA's James Webb Space Telescope, now under construction. Webb will be able to observe them to characterize planetary atmospheres and search for signs of life in their atmospheres.

Planets TESS identifies may also make excellent targets for observations by ground-based extremely large telescopes currently being built, the researchers note, as the brightness of their host stars would make them easier to characterize.

In addition to Kaltenegger, Joshua Pepper of Lehigh University and Keivan Stassun and Ryan Oelkers of Vanderbilt University contributed to the catalog, which draws from one originally developed at Vanderbilt that contains hundreds of millions of stars.

Read more at Science Daily

Rivers raged on Mars late into its history

A photo of a preserved river channel on Mars, taken by an orbiting satellite, with color overlaid to show different elevations (blue is low, yellow is high).

Long ago on Mars, water carved deep riverbeds into the planet's surface -- but we still don't know what kind of weather fed them. Scientists aren't sure, because their understanding of the Martian climate billions of years ago remains incomplete.

A new study by University of Chicago scientists catalogued these rivers to conclude that significant river runoff persisted on Mars later into its history than previously thought. According to the study, published March 27 in Science Advances, the runoff was intense -- rivers on Mars were wider than those on Earth today -- and occurred at hundreds of locations on the red planet.

This complicates the picture for scientists trying to model the ancient Martian climate, said lead study author Edwin Kite, assistant professor of geophysical sciences and an expert in both the history of Mars and climates of other worlds. "It's already hard to explain rivers or lakes based on the information we have," he said. "This makes a difficult problem even more difficult."

But, he said, the constraints could be useful in winnowing the many theories researchers have proposed to explain the climate.

Mars is crisscrossed with the distinctive tracks of long-dead rivers. NASA's spacecraft have taken photos of hundreds of these rivers from orbit, and when the Mars rover Curiosity landed in 2012, it sent back images of pebbles that were rounded -- tumbled for a long time in the bottom of a river.

It's a puzzle why ancient Mars had liquid water. Mars has an extremely thin atmosphere today, and early in the planet's history, it was also only receiving a third of the sunlight of present-day Earth, which shouldn't be enough heat to maintain liquid water "Indeed, even on ancient Mars, when it was wet enough for rivers some of the time, the rest of the data looks like Mars was extremely cold and dry most of the time," Kite said.

Seeking a better understanding of Martian precipitation, Kite and his colleagues analyzed photographs and elevation models for more than 200 ancient Martian riverbeds spanning over a billion years. These riverbeds are a rich source of clues about the water running through them and the climate that produced it. For example, the width and steepness of the riverbeds and the size of the gravel tell scientists about the force of the water flow, and the quantity of the gravel constrains the volume of water coming through.

Their analysis shows clear evidence for persistent, strong runoff that occurred well into the last stage of the wet climate, Kite said.

The results provide guidance for those trying to reconstruct the Martian climate, Kite said. For example, the size of the rivers implies the water was flowing continuously, not just at high noon, so climate modelers need to account for a strong greenhouse effect to keep the planet warm enough for average daytime temperatures above the freezing point of water.

The rivers also show strong flow up to the last geological minute before the wet climate dries up. "You would expect them to wane gradually over time, but that's not what we see," Kite said. The rivers get shorter -- hundreds of kilometers rather than thousands -- but discharge is still strong. "The wettest day of the year is still very wet."

It's possible the climate had a sort of "on/off" switch, Kite speculated, which tipped back and forth between dry and wet cycles.

Read more at Science Daily

Discovery of life-extension pathway in worms demonstrates new way to study aging

Caenorhabditis elegans.

An enzyme-blocking molecule can extend the lifespan of Caenorhabditis elegans roundworms by as much as 45 percent, largely by modulating a cannabinoid biological pathway, according to a study from scientists at Scripps Research.

The scientists, whose work is published on March 25 in Nature Chemical Biology, also showed that the lifespan-extending cannabinoid pathway in C. elegans is related in unexpected ways to cannabinoid pathways found in humans and other mammals.

"This study reveals a new life-extension pathway, but more broadly, it introduces a powerful method for applying chemical probes to lab animals such as worms to discover biology that may be relevant to humans," says study senior author Benjamin Cravatt, PhD, Professor and Gilula Chair of Chemical Biology at Scripps Research.

Cravatt is known for his development of advanced "chemical proteomics" methods for studying enzymes and the biological pathways they regulate. In the new study his team deployed these methods to investigate aging in C. elegans roundworms. The tiny worms normally live for just a few weeks -- compared to two or three years for lab mice -- making them, in principle, more practical for lifespan studies.

Lifespan studies using C. elegans worms typically involve the deletion or silencing of a particular gene in the embryonic stage of life to see if that extends the average lifespan of affected animals. The Cravatt team's approach, by contrast, was to use small-molecule compounds to disrupt enzyme-related pathways in adult worms, in the hope that this would uncover pathways that regulate lifespan.

"The beauty of this approach is that any lifespan-extending compounds we identify can be useful tools to study whether the same mechanisms and targets also modulate aging in mammals," says study co-author Michael Petrascheck, PhD, associate professor in the Department of Molecular Medicine at Scripps Research.

The team used a library of about 100 such compounds, all known to inhibit enzymes called serine hydrolases in mammals. "Metabolic processes are very important in determining the rate of aging and lifespan, and serine hydrolases are major metabolic enzymes, so we thought there was a good chance we'd find an important aging-related enzyme this way," says study first author Alice Chen, a graduate student in the Cravatt lab.

After finding ways to get the compounds through the tough outer skin of the worms, Chen tested them on worms that were 1 day into adulthood, and found that some of the compounds extended average worm lifespan by at least 15 percent. One, a carbamate compound called JZL184, extended worm lifespan by 45 percent at the optimal dose. More than half the worms treated with JZL184 were still alive and apparently healthy at 30 days, a time when virtually all untreated worms were dead of old age.

JZL184 was originally developed by the Cravatt lab as an inhibitor of the mammalian enzyme monoacylglycerol lipase (MAGL), whose normal job includes the breakdown of a molecule called 2-AG. The latter is an important neurotransmitter and is known as an endogenous cannabinoid ("endocannabinoid") because it activates one of the receptors hit by the main psychoactive component in cannabis.

Curiously however, a corresponding MAGL enzyme does not exist in C. elegans worms, so JZL184's target in these animals was a mystery. Chen soon found, though, that one of the main target enzymes for JZL184 in worms was fatty acid amide hydrolase 4 (FAAH-4). Although FAAH-4 and MAGL are not related in terms of their amino-acid sequences or 3-D folds, further experiments revealed, surprisingly, that FAAH-4 in worms does what MAGL does in humans and other mammals: it breaks down 2-AG.

2-AG has been linked to aging in mammals; one recent study found evidence that its levels fall in the brains of aging mice, likely due to greater MAGL activity. The results suggest, then, that studying the FAAH-4/2-AG pathway in worms could one day yield lifespan-extending strategies for humans.

"It seems at least plausible at this point that both worms and mammals have a cannabinoid-related signaling pathway that affects longevity and possibly aging-related disorders," Cravatt says.

The study demonstrates more generally how libraries of small-molecule compounds and associated proteomics techniques can be used to reveal biological pathways that evolutionarily distant lab animals such as worms have in common with humans.

"In principle, with this approach one can quickly find a compound that has a desired biological effect and also find the target through which it works, all in a live and relatively complex model organism," Cravatt says.

Read more at Science Daily

Earth's deep mantle flows dynamically

Cross-sections of Earth’s mantle down to 1,400 km depth showing changes in its flow as ancient ocean beds fall into Earth’s deep interior.

As ancient ocean floors plunge over 1,000 km into the Earth's deep interior, they cause hot rock in the lower mantle to flow much more dynamically than previously thought, finds a new UCL-led study.

The discovery answers long-standing questions on the nature and mechanisms of mantle flow in the inaccessible part of deep Earth. This is key to understanding how quickly Earth is cooling, and the dynamic evolution of our planet and others in the solar system.

"We often picture the Earth's mantle as a liquid that flows but it isn't -- it's a solid that moves very slowly over time. Traditionally, it's been thought that the flow of rock in Earth's lower mantle is sluggish until you hit the planet's core, with most dynamic action happening in the upper mantle which only goes to a depth of 660 km. We've shown this isn't the case after all in large regions deep beneath the South Pacific Rim and South America," explained lead author, Dr Ana Ferreira (UCL Earth Sciences and Universidade de Lisboa).

"Here, the same mechanism we see causing movement and deformation in the hot, pressurised rock in the upper mantle is also occurring in the lower mantle. If this increased activity is happening uniformly over the globe, Earth could be cooling more rapidly than we previously thought," added Dr Manuele Faccenda, Universita di Padova.

The study, published today in Nature Geoscience by researchers from UCL, Universidade de Lisboa, Universita di Padova, Kangwon National University and Tel Aviv University, provides evidence of dynamic movement in the Earth's lower mantle where ancient ocean floors are plunging towards the planet's core, crossing from the upper mantle (up to ~660 km below the crust) to the lower mantle (~660 -- 1,200 km deep).

The team found that the deformation and increased flow in the lower mantle is likely due to the movement of defects in the crystal lattice of rocks in the deep Earth, a deformation mechanism called "dislocation creep," whose presence in the deep mantle has been the subject of debate.

The researchers used big data sets collected from seismic waves formed during earthquakes to probe what's happening deep in Earth's interior. The technique is well established and comparable to how radiation is used in CAT scans to see what's happening in the body.

"In a CAT scan, narrow beams of X-rays pass through the body to detectors opposite the source, building an image. Seismic waves pass through the Earth in much the same way and are detected by seismic stations on the opposite side of the planet to the earthquake epicentre, allowing us to build a picture of the structure of Earth's interior," explained Dr Sung-Joon Chang, Kangwon National University.

By combining 43 million seismic data measurements with dynamic computer simulations using the UK's supercomputing facilities HECToR, Archer and the Italian Galileo Computing Cluster, CINECA the researchers generated images to map how the Earth's mantle flows at depths of ~1,200 km beneath our feet.

They revealed increased mantle flow beneath the Western Pacific and South America where ancient ocean floors are plunging towards Earth's core over millions of years.

This approach of combining seismic data with geodynamic computer modelling can now be used to build detailed maps of how the whole mantle flows globally to see if dislocation creep is uniform at extreme depths.

The researchers also want to model how material moves up from the Earth's core to the surface, which together with this latest study, will help scientists better understand how our planet evolved into its present state.

Read more at Science Daily

Deep time tracking devices: Fossil barnacles reveal prehistoric whale migrations

Fossil whale barnacles from the Pleistocene were retrieved from the Burica Peninsula of Panama for analyses.

Many whales take long journeys each year, spending summers feeding in cold waters and moving to warm tropical waters to breed. One theory suggests that these long-distance migrations originated around 5 million years ago, when ocean productivity became increasingly patchy. But patterns of ancient whale migrations have, until recently, been shrouded in mystery. Scientists from the Smithsonian Tropical Research Institute (STRI) and the University of California, Berkeley approached this question with an ingenious technique: barnacles.

"Instead of looking for clues to migration patterns from the whale's bones, we used hitch-hiking whale barnacles instead," said Larry Taylor, STRI visiting scientist and doctoral student at UC Berkeley who led the study.

Barnacles are crustaceans (crabs, lobsters, shrimp) that live stuck in one place in a hard shell. Most glue themselves to rocks, but whale barnacles attach to a whale's skin by sucking the skin in.

"Whale barnacles are usually species specific -- one species of barnacle on one type of whale," said Aaron O'Dea, staff scientist at STRI and co-author of the study. "This gives the barnacle several advantages -- a safe surface to live on, a free ride to some of the richest waters in the world and a chance to meet up with others when the whales get together to mate."

As whale barnacles grow, their shells record the conditions by taking up oxygen isotopes from the water. By carefully reading the unique isotope signatures left in the shells, the barnacles can reveal the water bodies the barnacle passed through, helping reconstruct the whale's movements over time.

The study, published in Proceedings of the National Academy of Sciences looked at a number of fossil and modern whale barnacles from the Pacific coast of Panama and California.

"The signals we found in the fossil barnacles showed us quite clearly that ancient humpback and grey whales were undertaking journeys very similar to those that these whales make today," Taylor said. "It seems like the summer-breeding and winter-feeding migrations have been an integral part of the way of life of these whales for hundreds of thousands of years."

"We want to push the technique further back in time and across different whale populations," said Seth Finnegan, co-author from UC Berkeley. "Hunting for fossil whale barnacles is easier than whales, and they provide a wealth of information waiting to be uncovered."

From Science Daily

Yellowstone elk don't budge for wolves, say scientists

Utah State University researchers and their colleagues have shown that wolves reintroduced to Yellowstone National Park in the mid-1990s have negligible impacts on the movements of adult female elk that roam the northern Yellowstone winter range.

Elk roam the winter range that straddles the northern boundary of Yellowstone National Park with little regard for wolves, according to a new study illustrating how elk can tolerate living in close proximity to the large predator.

The study offers new insight into how wolves can have negligible impacts on elk movements, and how elk may simply ignore the risk of wolf predation while navigating the landscape in search of forage. It also adds to a growing body of evidence that changes in elk distribution and vegetation conditions in northern Yellowstone since wolf reintroduction in the mid-1990s are not caused by wolves altering elk movement behavior.

Utah State University researchers Dan MacNulty and Michel Kohl co-led the study, published in the Journal of Animal Ecology, with Jeremy Cusack (University of Stirling), Tim Coulson (University of Oxford), Matt Metz (University of Montana), Doug Smith and Dan Stahler (Yellowstone National Park). Several organizations funded the research, including the National Science Foundation, Natural Environment Research Council, Yellowstone Forever, The Tapeats Fund, Perkins-Prothro Foundation, and the National Park Service. The Park-led wolf and elk monitoring programs provided data for the project.

The team used global positioning system (GPS) radio-collars to track the movements of elk and wolves across four winters between 2012 and 2016. They tracked 34 adult female elk and at least one member of each dominant wolf pack. The collars recorded the location of the animals every 1-3 hours, providing comprehensive data on how they used the landscape. The team tested if elk avoided wolves that were in close proximity, and if elk avoided 'risky areas' where they might be killed by wolves, including where wolf densities were high; where wolves had previously killed elk; and open grasslands where wolves often hunted.

"We compared recorded elk movements with those from a simulation that described how elk would move if they completely ignored wolves and risky areas" says MacNulty, who has studied wolf-elk interactions in northern Yellowstone since 1995 and is an associate professor in USU's Department of Wildland Resources and Ecology Center. "In 90% of cases, there was no difference between real and simulated elk movements, indicating that our sample of real elk mostly ignored the risk of wolf predation."

According to Cusack, the lead author of the study, most elk did not alter the location and configuration of their annual winter home ranges to minimize overlap with wolves and risky areas, and none bothered to steer around wolves that were in the immediate vicinity. "A few elk avoided open grasslands during daylight hours when wolves were most active, which mirrors the result of a separate recent study that examined finer-scale elk movements in the early 2000s when wolves and elk were more numerous," explained Cusack.

The findings are also in line with other studies of northern Yellowstone elk, including one that compared elk movements before and after wolf reintroduction and found that "in winter, elk did not spatially separate themselves from wolves." Another study reported that "elk did not grossly modify their migration timing, routes, or use areas after wolf restoration."

Why don't elk budge for wolves? "A main reason is that elk tend to be philopatric, which means they have an inherent tendency to habitually return to the same wintering and summering areas year after year," says MacNulty. "Familiarity with an area helps them find the high quality forage they need, and this outweighs the small chance they encounter and fall prey to wolves."

MacNulty and Cusack estimated that elk in their study encountered wolves once every 7 to 11 days, and previous research found that elk frequently survive their encounters with wolves. Low risk of predation was also reflected in relatively high rates of annual survival, particularly among younger adults. "Elk in their prime do not have a massive incentive to avoid wolves, especially in winter when forage is scarce," explains MacNulty.

He says that elk intransigence towards wolves is a reminder that altered movement behavior is not the only way prey species avoid predation.

"Antipredator behaviors during encounters -- including fighting back, grouping, and running -- are effective ways for large-bodied, philopatric prey like elk to avoid predation without abandoning or reconfiguring their home ranges," he says.

Read more at Science Daily

Ancient Caribbean children helped with grocery shopping in AD 400

Researchers found a variety of modified shells at the St. Thomas site, including three beads cut from shell and polished, top row, two beads made from Oliva shells, bottom left, and two Cyphoma shells.

Researchers have long thought that snail and clam shells found at Caribbean archaeological sites were evidence of "starvation food" eaten in times when other resources were lacking. Now, a University of Florida study suggests these shells may be evidence of children helping with the grocery shopping -- A.D. 400 style.

Researchers found thousands of discarded shells at a site in downtown St. Thomas in the U.S. Virgin Islands, likely evidence of ancient Saladoid children foraging for shellfish. Adult foragers typically would discard shells immediately after extracting the meat, meaning few shells made it back to archaeological sites, said William Keegan, curator of Caribbean archaeology at the Florida Museum of Natural History. This site, however, was littered with them.

"It's not that people were starving. It's that children were contributing to their own subsistence in a meaningful and very efficient way," Keegan said. "We need to think of children as active members that influence site materials and their distribution. It changes the whole attitude about the collection in the archaeological site."

For the most part, children have remained invisible to archaeologists until now, Keegan said. This study, the first to document child labor in an archaeological context, provides an important model for identifying children in the past and their contributions to their communities.

"Children are really the last group to receive any attention because to archaeology, they sort of look like little adults," he said. "Efforts to identify children so far have emphasized badly made objects, miniatures and things that look like toys -- it isn't a complete perspective."

Children may have had a role in foraging, which for the Saladoid people meant collecting mollusks for food.

"If your parent needs to go to the grocery store, you have to go with them," Keegan said. "If you can do more than pull candy off the shelf, then you're that much more helpful."

Shells deposited in middens -- mounds of shells and sediment that were once ancient garbage dumps -- led Keegan's research team to believe that shellfish had been intentionally brought to the site, eaten and the shells then thrown away. The team also developed seven criteria to help determine if shellfish at archaeological sites were collected by children.

Shellfish collected by children are most easily identified by variety and size, Keegan said. Child foragers tend to be generalists, meaning that they're more likely to collect small shells indiscriminately. This research suggests that small, easy to transport and low-yield mollusks found in high amounts on a site indicate the presence of child foragers, he said.

"It looked like someone had sent a biology student with a one meter square and told them, 'Collect everything,'" Keegan said. "You can certainly collect a whole bucket of these things and you've got a good meal, but it's a waste of time for an adult to focus on those really small resources when they could be out collecting specific snails and clams that they know they can get a certain nutritional return on."

Recent construction has disturbed much of the site, and researchers were only able to excavate a snapshot of what was once there, Keegan said.

Because the Caribbean is a largely understudied area in archaeology, Keegan and his team had few ethnographic descriptions of the Saladoid's lifestyles to draw from. They chose to compare their findings with current research in the Pacific Islands, where foraging habits and available resources have remained virtually unchanged for millennia.

"It's not a direct application," Keegan said. "It's an analogy that shows what we're seeing in the living population is consistent with what we see in an archaeological population."

Evidence suggests that foraging together was a way Saladoid people built kinship, a practice still seen today in the Pacific Islands. The Saladoid people were a matrilocal society, meaning familial lineage was traced through women and men were frequently absent from day-to-day life.

"The women would often go on trips with children to collect things farther away," Keegan said. "The community functions holistically. By about age 15, children are involved in fully adult activities."

Keegan's work suggests that in some respects, children could actually outperform adults at certain tasks. Whereas adults focused on collecting larger shellfish from deeper waters, children were able to scour shallow areas for smaller shellfish that would be difficult for adult fingers to grasp.

"Children like being included. The same sorts of things children need in traditional societies are basically what we still need today to grow up to be healthy, useful adults," Keegan said. "In fact, it wasn't uncommon for children to collect small animals as pets."

Because the site is located on St. Thomas' main street, Keegan and his team were able to engage bystanders in their discoveries.

"What I think is unusual is that the road caps the site. Below the pipes, everything was completely intact," Keegan said. "The archaeologists were fenced in -- all day long people were coming up to the fence, and we were showing them what we had, but that's all part of it. We want people to get excited about what we're doing."

Excavation was a collaborative effort that included several experts from different disciplines, lending a broader perspective to the team's findings, Keegan said. The team was assembled by David Hayes, a founding member of the St. Croix Archaeological Society and project collaborator.

Read more at Science Daily

Listening to the quantum vacuum

Louisiana State University Department of Physics & Astronomy Associate Professor Thomas Corbitt and his team of researchers now present the first broadband, off-resonance measurement of quantum radiation pressure noise in the audio band, at frequencies relevant to gravitational wave detectors, as reported in the scientific journal Nature.

Since the historic finding of gravitational waves from two black holes colliding over a billion light years away was made in 2015, physicists are advancing knowledge about the limits on the precision of the measurements that will help improve the next generation of tools and technology used by gravitational wave scientists.

Louisiana State University Department of Physics & Astronomy Associate Professor Thomas Corbitt and his team of researchers now present the first broadband, off-resonance measurement of quantum radiation pressure noise in the audio band, at frequencies relevant to gravitational wave detectors, as reported today in the scientific journal Nature.

The research was supported by the National Science Foundation, or NSF, and the results hint at methods to improve the sensitivity of gravitational-wave detectors by developing techniques to mitigate the imprecision in measurements called "back action," thus increasing the chances of detecting gravitational waves.

Corbitt and researchers have developed physical devices that make it possible to observe -- and hear -- quantum effects at room temperature. It is often easier to measure quantum effects at very cold temperatures, while this approach brings them closer to human experience. Housed in miniature models of detectors like LIGO, or the Laser Interferometer Gravitational-Wave Observatory, located in Livingston, La., and Hanford, Wash., these devices consist of low-loss, single-crystal micro-resonators -- each a tiny mirror pad the size of a pin prick, suspended from a cantilever. A laser beam is directed at one of these mirrors, and as the beam is reflected, the fluctuating radiation pressure is enough to bend the cantilever structure, causing the mirror pad to vibrate, which creates noise.

Gravitational wave interferometers use as much laser power as possible in order to minimize the uncertainty caused by the measurement of discrete photons and to maximize the signal-to-noise ratio. These higher power beams increase position accuracy but also increase back action, which is the uncertainty in the number of photons reflecting from a mirror that corresponds to a fluctuating force due to radiation pressure on the mirror, causing mechanical motion. Other types of noise, such as thermal noise, usually dominate over quantum radiation pressure noise, but Corbitt and his team, including collaborators at MIT, have sorted through them. Advanced LIGO and other second and third generation interferometers will be limited by quantum radiation pressure noise at low frequencies when running at their full laser power. Corbitt's paper in Nature offers clues as to how researchers can work around this when measuring gravitational waves.

"Given the imperative for more sensitive gravitational wave detectors, it is important to study the effects of quantum radiation pressure noise in a system similar to Advanced LIGO, which will be limited by quantum radiation pressure noise across a wide range of frequencies far from the mechanical resonance frequency of the test mass suspension," Corbitt said.

Corbitt's former academic advisee and lead author of the Nature paper, Jonathan Cripe, graduated from LSU with a Ph.D. in physics last year and is now a postdoctoral research fellow at the National Institute of Standards and Technology:

"Day-to-day at LSU, as I was doing the background work of designing this experiment and the micro-mirrors and placing all of the optics on the table, I didn't really think about the impact of the future results," Cripe said. "I just focused on each individual step and took things one day at a time. [But] now that we have completed the experiment, it really is amazing to step back and think about the fact that quantum mechanics -- something that seems otherworldly and removed from the daily human experience -- is the main driver of the motion of a mirror that is visible to the human eye. The quantum vacuum, or 'nothingness,' can have an effect on something you can see."

Read more at Science Daily

Scientist constructs artificial photosynthetic cells

These are schematics of the artificial photosynthetic cell encapsulating artificial organelle consists of ATP synthase and bacteriorhodopsin. The artificial organelle synthesizes ATP by light illumination. The photosynthesized ATP was consumed for transcription, GTP synthesis, or translation.

A team led by associate professor Yutetsu Kuruma of the Earth-Life Science Institute (ELSI) at Tokyo Institute of Technology has constructed simple artificial cells that can produce chemical energy that helps synthesize parts of the cells themselves. This work marks an important milestone in constructing fully photosynthetic artificial cells, and may shed light on how primordial cells used sunlight as an energy source early in life's history.

Scientists build artificial cells as models of primitive cells, as well as to understand how modern cells function. Many sub-cellular systems have now been built by simply mixing cell components together. However, real living cells construct and organize their own components. It has also been a long time goal of research to build artificial cells that can also synthesize their own constituents using the energy available in the environment.

The Tokyo Tech team combined a cell-free protein synthesis system, which consisted of various biological macromolecules harvested from living cells, and small protein-lipids aggregates called proteoliposomes, which contained the proteins ATP synthase and bacteriorhodopsin, also purified from living cells, inside giant synthetic vesicles. ATP synthase is a biological protein complex that uses the potential energy difference between the liquid inside a cell and the liquid in the cell's environment to make the molecule adenosine triphosphate (ATP), which is the energy currency of the cell. Bacteriorhodopsin is a light-harvesting protein from primitive microbes that uses light energy to transport hydrogen ions outside of the cell, thus generating a potential energy difference to help ATP synthase operate. Thus, these artificial cells would be able to use light to make a hydrogen ion gradient that would help make the fuel cells use to run their sub-cellular systems, including making more protein.

Just as the scientists hoped, the photosynthesized ATP was consumed as a substrate for transcription, the process by which biology makes messenger RNA (mRNA) from DNA, and as an energy for translation, the process by which biology makes protein from mRNA. By also including the genes for parts of the ATP synthase and the light-harvesting bacteriorhodopsin, these processes also eventually drive the synthesis of more bacteriorhodopsin and the constituent proteins of ATP synthase, a few copies of which were included to "jump-start" the proteoliposome. The newly formed bacteriorhodopsin and ATP synthase parts then spontaneously integrated into the artificial photosynthetic organelles and further enhanced ATP photosynthesis activity.

As professor Kuruma states "I have been trying for a long time to construct a living artificial cell, especially focusing on membranes. In this work, our artificial cells were wrapped in lipid membranes, and small membrane structures were encapsulated inside them. In this way, the cell membrane is the most important aspect of forming a cell, and I wanted to show the importance of this point in the study of artificial cell and feedback in origins of life studies."

Kuruma thinks the most impact point of this work is that artificial cells can produce energy to synthesize the parts of the cell itself. This means that the artificial cells could be made to be energetically independent and then it would be possible to construct self-sustaining cells, just like actual biological ones cells. "The most challenging thing in this work was the photosynthesis of the bacteriorhodopsin and the ATP synthase parts, which are membrane proteins. We tried to photosynthesize a full ATP synthase, which has 8 kinds of component proteins, but we could not because of the low productivity of the cell-free protein synthesis system. But, if it was upgraded, we may photosynthesize the whole 8 kinds component proteins."

Read more at Science Daily