Biodiversity Plunges Below Levels 'Safe' for Humans

Having a range of different plant and animal species helps guarantee the health of the Earth, but a study Thursday suggested that biodiversity may be declining beyond safe levels.

On 58 percent of the world's land surface, which is home to 71 percent of the global population, "the level of biodiversity loss is substantial enough to question the ability of ecosystems to support human societies," said the report in the US journal Science.

Researchers at University College London based their study on data from hundreds of international scientists, crunching 2.38 million records for more than 39,000 species at more than 18,000 sites in the world.

They sought to estimate how biodiversity has changed over time, particularly since humans arrived and built on land.

Areas most affected included grasslands, savannas and shrublands, followed by many of the world's forests and woodlands, said the report.

Using a reference known as the Biodiversity Intactness Index (BII), which captures changes in species abundance, researchers said a safe limit of change is generally considered about a 10 percent reduction in BII.

In other words, "species abundance within a given habitat is 90 percent of its original value in the absence of human land use," said the report.

The study showed that global biodiversity has fallen below that threshold, to 84.6 percent.

"This is the first time we've quantified the effect of habitat loss on biodiversity globally in such detail and we've found that across most of the world biodiversity loss is no longer within the safe limit suggested by ecologists," said lead researcher Tim Newbold of UCL.

"In many parts of the world, we are approaching a situation where human intervention might be needed to sustain ecosystem function."

Read more at Discovery News

Ducklings Are Surprisingly Smart, Abstract Thinkers

Newly hatched ducklings are capable of abstract thinking, according to research that finds these little young birds quickly get the concepts of sam and different.

This ability had only been known in animals whose intelligence is well documented, such as humans, other apes, crows and parrots. Ducklings even take the skill to a whole other level above the other animals that are not of our own species.

"To our knowledge this is the first demonstration of a non-human organism learning to discriminate between abstract relational concepts without any reinforcement training," Alex Kacelnik of Oxford University's Department of Zoology said in a press release.

"The other animals that have demonstrated this ability have all done so by being repeatedly rewarded for correct performance, while our ducklings did it spontaneously, thanks to their predisposition to imprint when very young," he added. "And because imprinting happens so quickly, the ducklings learned to discriminate relational concepts much faster than other species, and with a similar level of precision."

Ducklings with their mother in River Cherwell at Oxford, U.K.

He and his team explained that imprinting, which allows ducklings to identify and follow their mother, can occur in as little as 15 minutes after the baby birds hatch. The scientists say that it is a powerful form of learning that can allow ducklings to follow any moving object, so long as they see it within the species' typical "sensitive period" for imprinting.

Kacelnik and colleagues initially presented ducklings with a pair of objects either the same as, or different from, each other in shape or in color. The objects moved around the ducklings in a circle, operated by a mobile-type motor from above. At this stage, the ducklings imprinted on the pairs of moving objects that were presented to them.

Next, each duckling was allowed to follow one of two pairs of objects composed of shapes or colors to which the duckling had not previously been exposed. For example, if an individual duckling had originally been exposed to a pair of spherical objects, in the choice test it might have had to choose between following a pair of pyramids (same) or a pair made up of one cube and one cuboid (different).

The ducklings showed that they understood the concepts of "same" and "different," since they elected to follow objects that matched one of these two relationships, depending on what they had imprinted on earlier, even though the baby birds had never before seen these newer sets of particular items and colors.

Read more at Discovery News

Trove of Bronze Age Textiles Found at Britain's Pompeii

A treasure trove of finely woven textiles has been unearthed during the final part of a 10-month excavation at a site in the UK county of Cambridgeshire which has been described as Britain's Pompeii.

Known as Must Farm, the settlement was home to several families who lived in a number of circular wooden houses built on stilts above a river. It was abandoned in haste 3,000 years ago as a giant fire destroyed the houses. The dwelings fell into the river, where thick silt and clay preserved the contents.

Charred in the fire that destroyed the houses and buried in the anaerobic waterlogged environment, the black, fragile textile fragments are some of the most finely-made Bronze Age fabrics ever discovered in Europe.

The fragments were all found inside the round houses along with plant fibers, balls of thread, and tools for spinning and weaving.

"This illustrates different stages of textile production," Susanna Harris, an expert in fabrics and a lecturer in archaeology at the University of Glasgow, said.

Some woven textiles are of superfine quality, even by modern standards, with threads around the diameter of coarse human hair (100 microns).

Fired clay weights found in the houses suggest the textile was produced using two clay weights so that the warp threads were held under tension on a loom.

"We found different types of fabric at Must Farm: woven textiles, a basketry technique called twining (weft twining) and knotted net," Harris told Discovery News.

"The textiles could have been used for clothing, although now they are just fragments. Nets could have been used for fishing, trapping or to carry things. The twining is a coarser material and could have been used for matting or for a range of other things such as containers or household item," Harris added.

Most of the superfine fabrics were made of linen. People used flax, a domesticated crop known to have been farmed in Britain from the Neolithic period onwards.

But fabrics were also made using wild species available in the local environment, such as the non-stinging fen nettle and lime bast, processed from the inner bark of lime trees.

"The textiles would have been soft and supple," Harris said.

Carried out by the University of Cambridge, the excavation has now come to a close. In the past months, archaeologists found an extraordinary time capsule buried just over six feet below the ground surface, where the river bed actually was in 1000-800 BC.

Such was the level of preservation that the footprints of those living there are still visible in the waterlogged sediments.

The way the objects were found indicate people were forced to leave everything behind when the houses caught on fire.

They left their clothing, jewelry, tools, furniture, and abandoned the meals in the cooking pots.

It is not known whether it was an accident or fire was set deliberately by hostile forces.

However, tree-ring analysis of the oak structures has suggested that at the time of the fire, the houses were still new and had only been lived in for a few months.

Read more at Discovery News

Turtles Evolved Shells for Digging, Not Protection

Artistic rendering of the early turtle ancestor Eunotosaurus (foreground) burrowing with a herd of Bradysaurus nearby.

The age-old question, "Why do turtles have shells?" would seem to have an obvious answer, protection, yet new research finds that turtles first evolved shells to help with digging underground to escape hot, dry environments.

The findings, published in the journal Current Biology, add to the growing list of key anatomical features that evolved to solve one problem but were then applied to another function. The features, known as "exaptations," include everything from feathers to the gas bladder of early fish, which evolved to become lungs in terrestrial animals.

The new study focused on a 260-million-year-old fossil of the oldest "proto turtle," or early turtle ancestor, which in this case is called Eunotosaurus africanus. Its remains were found by then 8-year-old Kobus Snyman, who spotted it on his father's farm in the Karoo region of South Africa.

"The weather was extremely arid in the Karoo Basin of South Africa 260 million years ago," lead author Tyler Lyson said. "A common mechanism for dealing with arid environments, among both extant and extinct animals, is to burrow underground. Burrows provide a more moderate and stable environment."

Lyson, who is the curator of vertebrate paleontology at the Denver Museum of Nature & Science, and his colleagues studied the fossil found by Snyman, as well as other Eunotosaurus specimens unearthed by two of the study's co-authors, Roger Smith and Bruce Rubidge from the University of Witwatersrand.

They determined that the animal's broad ribs, which over time replaced soft tissue with bone, provided a stable base from which Eunotosaurus could operate its front leg digging.

"A stable base is needed to counteract the force of the digging mechanism, in this case the forelimbs," Lyson explained. "Digging animals thus have adaptations to dig burrows (large hands, large claws, strong forelimbs, etc.) and adaptations to deal with counteracting the digging mechanism force."

The modification of the ribs that eventually led to the shell resulted in other dramatic changes, since the ribs and nearby muscles are involved in both breathing and locomotion. In fact, some early animals could not breathe and run at the same time. To this day, animals that retain such an early breathing mechanism, such as lizards, must hold their breath as they run.

In turtles, as the ribs broadened over millions of years, they became less effective at helping to ventilate the lungs and more associated with locomotion, according to the researchers. The nearby hypoxial muscles, on the other hand, took on a purely respiratory role over time.

"Such a division of function allows turtles to breathe and walk simultaneously and helps them deal with the constraint of having a dual function for both the ribs and muscles," Lyson said.

The extreme changes turned out to be extremely fortuitous for turtles. When the Permian-Triassic mass extinction occurred 252 million years ago, burrowing likely helped to save them, Lyson believes.

When the Triassic-Jurassic extinction event happened much later, 66 million years ago, turtles had evolved to become largely aquatic, with their water environment helping to buffer them from the extinction that killed off dinosaurs (save for some birds) and many other animals. The ability to dig well helped the turtles live on both land and in water.

Hans-Dieter Sues, curator and department chairman of vertebrate paleontology at the Smithsonian Museum of Natural History, told Discovery News that shells helped to protect the vital organs of water-dwelling early turtles. He also believes that shells "may have initially helped with buoyancy control by making the animal heavier."

Read more at Discovery News

Dinosaurs Might Have Gone Up in Smoke

Artist's concept of a planetary collision.

A new theory on the extinction of dinosaurs and other animals at the end of the Cretaceous says that massive amounts of smoke and soot following the Chicxulub asteroid impact led to a devastating domino effect 66 million years ago.

The asteroid, which slammed into Earth at what is now Mexico's Yucatan Peninsula, not only immediately burnt some dinosaurs and other animals to a crisp, but also, according to the new study, hit the worst possible spot: an oil-rich area.

"The stratospheric soot was ejected from the oil-rich area by the asteroid impact and was spread globally," Kunio Kaiho of Tohoku University told Discovery News.

"The soot aerosols caused sufficiently colder climates at mid–high latitudes and drought with milder cooling at low latitudes on land, in addition to causing limited cessation of photosynthesis in global oceans within a few months to two years after the impact, followed by surface-water cooling in global oceans in a few years."

In short, it was curtains for dinosaurs and many other animals shortly after the asteroid hit.

The scientists found that sediments in both locations for the target time period shared the same composition of combusted organic molecules.

"Therefore, this is the soot from the asteroid crash," Kaiho said.

He and his team created a global climate model at the Meteorological Research Institute, and found that soot in the atmosphere after the asteroid impact would have produced colder climates at mid-high latitudes leading to the extinction of most species in these regions.

The soot, however, would have also caused droughts accompanied by mild cooling at lower latitudes that would have led to the extinction of dinosaurs, but would have allowed crocodiles and certain other animals to survive.

Global climate change caused by soot aerosol following the Chicxulub asteroid strike.

Water-dwelling species would have still had some resources. Small mammals and reptiles could have burrowed underground.

"The different habitats of the dinosaurs and small mammals and reptiles would have been key factors in determining their extinction or survival," he said.

Some dinosaurs, of course, did survive: birds.

As for the dinosaurs that were not immediately killed by the asteroid, the drastic climate change following the asteroid strike would have led to loss of soil moisture and vegetation in many areas.

Kaiho said that herbivorous dinosaurs would have consumed the ever-decreasing available plants, resulting in the eventual disappearance of such food, "similar to overgrazing leading to desertification today."

As the plant-eating dinosaurs died out, so too did the remaining carnivorous dinosaurs, suggests the new paper.

In terms of dinosaurs literally going up in smoke, Manabu Sakamoto of the University of Reading, who has conducted other research on the dinosaur extinction event, told Discovery News, "Some dinosaurs definitely would have been instantly killed in the impact."

Sakamoto added that still other dinosaurs might have perished in a tsunami caused by the blast, but "the majority of the remaining dinosaurs would have likely starved to death as vegetation died out owing to the layer of ash that blacked out the sky (nuclear winter)."

Read more at Discovery News

New Dinosaur Had Tiny T.rex Arms

Tiny forelimbs were apparently all the rage in the Late Cretaceous, as paleontologists have discovered a new dinosaur that had small Tyrannosaurus rex-like arms.

The new dino, named Gualicho shinyae, shared T. rex's meat-loving ways, according to the paper, published in the journal PLOS ONE. In future, research on it could solve mysteries about its tiny arms as well as those of T. rex and other dinosaurs sporting this look.

"By learning more about how reduced forelimbs evolved, we may be able to figure out why they evolved," co-author Peter Makovicky, who is The Field Museum's curator of dinosaurs, said in a press release.

The new dinosaur Gualicho showing the fossils that were found along with its other likely anatomy.

The research team consisted of an international group of researchers from The Field Museum, Universidad Maimónides in Argentina, the Dinosaur Institute at the Natural History Museum of Los Angeles County, and the Gobierno de la Provincia de Río Negro in Argentina.

Akiko Shinya, The Field Museum's chief fossil preparator, found the remains for the dinosaur during an expedition to the fossil-rich Huincul Formation of northern Patagonia. The species name shinyae honors Shinya, while the generic name Gualicho derives from Gualichu, a spirit revered by Patagonia's Tehuelche people.

Akiko Shinya, the Field Museum's chief fossil preparator for whom the new dinosaur is named, with Gualicho shinyae at the dig site.

The team joked about "the curse of Gualicho," since they had some bad luck. At one point, a truck even rolled over with scientists inside, but everyone was OK, save for some cuts and bruises.

The dino Gualicho lived about 100–66 million years ago and was an allosaurid, referring to a type of medium-to-large carnivorous two-legged dinosaurs. The researchers estimate that Gualicho weighed around 1,000 pounds, comparable to the heft of a modern polar bear.

Read more at Discovery News

Supernovas Blasted Prehistoric Earth With Radiation

A false-color image of an unrelated supernova remnant, G292.0+1.8, taken by the Chandra X-ray telescope.

Cancers in animals could have increased slightly after our planet was blanketed with radiation from two prehistoric supernovae, according to new research.

The star explosions took place between 1.7 million and 8.7 million years ago, irradiating the landscape with high-energy cosmic rays. Cosmic rays hit Earth every day, but the stellar explosions would have increased the radiation striking our planet.

When the cosmic rays hit molecules in our atmosphere, a cascade of secondary particles such as X-rays, protons and muons are produced. Some muon radiation is normal, but the supernovae would have temporarily tripled the dose for land animals and animals living in shallow waters, said co-author Adrian Melott, a University of Kansas physics researcher, in a statement.

"I was expecting there to be very little effect at all," he said. "The supernovae were pretty far way — more than 300 light years — that's really not very close."

Artist's impression of cosmic rays, which usually originate from outside the solar system, entering the heliopause (the sun's region of influence).

The radiation would have given animals the equivalent dose of one additional CT scan in radiation per year. CT scans take X-ray images from several angles to let doctors look inside tumors and other objects. The night sky also would have bathed in blue light from the explosions, making it difficult for animals to sleep.

Some researchers have speculated that there could be a link between increased cosmic rays and a cooler climate on Earth, although that link isn't proven for sure. (Simply put, the theory associates cosmic rays with aerosols, which could produce clouds, which in turn reduces the amount of solar radiation on the surface.) If a connection could be made, Melott said it is possible the supernovae were associated with a known, smaller mass extinction 2.59 million years ago when Earth went through repeated ice ages.

Read more at Discovery News

Juno Sends Back First Orbital Photo of Jupiter

Image relayed by NASA's Juno spacecraft on July 10. Three of Jupiter's moons, Io, the innermost moon, Europa, upper right, and Ganymede, lower right, are visible.

Having survived being slingshot around Jupiter, NASA's Juno spacecraft turned its camera back on this week and snapped a picture of its new home.

The space probe ended a five-year flight to the biggest planet in the solar system on July 4 with a do-or-die breaking maneuver so it could shed speed and fall into Jupiter's gravity well.

Juno will take a couple of months to re-position itself for 37 looping orbits around the planet's poles, coming at closest approach to about 2,600 miles (4,100 kilometers) above Jupiter's cloud tops.

To avoid as much radiation as possible, Juno will buzz Jupiter only once every 14 days. Even though its instruments are inside a titanium vault, Juno is expected to be nearly electronically fried after 20 months.

Juno's orbit was designed to maximize the odds of a successful science mission, the primary goal of which is to measure how much water Jupiter contains. That information will serve as a yardstick for calculating how far from the sun the biggest planet formed, setting the stage for everything else in the solar system, including Earth and its fortuitous position conductive to the evolution of life.

This week, NASA got its first picture from Juno since its camera was turned back on following the probe's July 4 plunge through Jupiter's radioactive welcome mat.

The image was taken 9:30 a.m. EDT on Sunday when Juno was 2.7 million miles (4.3 million kilometers) from Jupiter on the outbound leg of the first of two planned 53.5-day capture orbits, NASA said.

The image, released on Tuesday, shows Jupiter's famed Great Red Spot, a gigantic atmospheric storm that astronomers on Earth have been watching for four centuries.

Read more at Discovery News

Clouds Shifting Toward Poles With Climate Change

Over the last three decades, global cloud patterns have changed, and mid-latitude storm tracks--the paths that cyclones travel in the Northern and Southern hemispheres--have been drifting toward our planet's poles, according to a new study published in Nature.

The changes, documented by researchers from Lawrence Livermore National Laboratory, Scripps Institution of Oceanography, University of California, Riverside and Colorado State University match those predicted by climate model simulations, and they've probably had added to global warming that is causing climate change.

Joel Norris, a climate researcher at Scripps, called the study "the first credible demonstration that cloud changes we expect from climate models and theory are currently happening."

Those findings are good news for scientists who for years have struggled to model the role of clouds in climate change. But as Veerabhadran Ramanathan of Scripps, who was not involved in the study, told Science magazine, that's not such good news for the planet and its inhabitants. The movement of clouds toward the polls is "problematic for our future" and makes efforts to slow warming more urgent, he said.

Clouds play an important role in climate change models because they both reflect solar radiation back into space (the albedo effect) and restrict the escape of heat into space. But calculating how those processes balance one another has been difficult, in part because clouds themselves are influenced by climate change, even as they influence it.

Another problem, according to the Science article, is that researchers have been compelled to use data from satellites that were not set up to look at clouds. Geostationary satellites, for example, look directly down at the Earth's surface, rather than using the slanted view that would make it easier to detect clouds.

To overcome those problems, Norris and his colleagues performed corrections that accounted for those imperfections in cloud data, and then studied the results for clear-term patterns.

In addition to the drift in storm tracks, the scientists also confirmed that subtropical dry regions are expanding, and that the tops of the tallest clouds are getting taller. All of these changes can worsen global warming.

Read more at Discovery News

Deepest ever look into Orion

This spectacular image of the Orion Nebula star-formation region was obtained from multiple exposures using the HAWK-I infrared camera on ESO's Very Large Telescope in Chile. This is the deepest view ever of this region and reveals more very faint planetary-mass objects than expected.

An international team has made use of the power of the HAWK-I infrared instrument on ESO's Very Large Telescope (VLT) to produce the deepest and most comprehensive view of the Orion Nebula to date. Not only has this led to an image of spectacular beauty, but it has revealed a great abundance of faint brown dwarfs and isolated planetary-mass objects. The very presence of these low-mass bodies provides an exciting insight into the history of star formation within the nebula itself.

The famous Orion Nebula spans about 24 light-years within the constellation of Orion (constellation), and is visible from Earth with the naked eye, as a fuzzy patch in Orion's sword. Some nebulae, like Orion, are strongly illuminated by ultraviolet radiation from the many hot stars born within them, such that the gas is ionised and glows brightly.

The relative proximity of the Orion Nebula makes it an ideal testbed to better understand the process and history of star formation, and to determine how many stars of different masses form.

Amelia Bayo (Universidad de Valparaíso, Valparaíso, Chile; Max-Planck Institut für Astronomie, Königstuhl, Germany), a co-author of the new paper and member of the research team, explains why this is important: "Understanding how many low-mass objects are found in the Orion Nebula is very important to constrain current theories of star formation. We now realise that the way these very low-mass objects form depends on their environment."

This new image has caused excitement because it reveals a unexpected wealth of very-low-mass objects, which in turn suggests that the Orion Nebula may be forming proportionally far more low-mass objects than closer and less active star formation regions.

Astronomers count up how many objects of different masses form in regions like the Orion Nebula to try to understand the star-formation process. Before this research the greatest number of objects were found with masses of about one quarter that of our Sun. The discovery of a plethora of new objects with masses far lower than this in the Orion Nebula has now created a second maximum at a much lower mass in the distribution of star counts.

These observations also hint tantalisingly that the number of planet-sized objects might be far greater than previously thought. Whilst the technology to readily observe these objects does not exist yet, ESO's future European Extremely Large Telescope (E-ELT), scheduled to begin operations in 2024, is designed to pursue this as one of its goals.

Read more at Science Daily