Month: April 2016

These Coral Reefs Have Become ‘Ghost Towns’ in Just a Few Months [Video]

A team of marine scientists has returned from nearly a month of scuba diving on coral reefs in the middle of the equatorial Pacific Ocean. What they saw will haunt them for a long time.

“It’s as if someone has thrown a fuzzy red/brown blanket over the reef, turning it all one color,” says Kim Cobb, a professor in Georgia Tech’s School of Earth and Atmospheric Sciences. “Right now it looks okay from afar, with all the coral structure still in place. But when you get up close, you see that it’s all dead, as far as the eye can see. It’s very eerie.”

“CHRISTMAS ISLAND’S CORAL REEFS ARE LIKE GHOST TOWNS NOW. THE STRUCTURES ARE ALL STILL THERE, BUT NO ONE IS HOME.”

Cobb and colleagues worked with biologist Julia Baum and her team of University of Victoria researchers on Kiritimati Island (also known as Christmas Island), the world’s largest coral atoll. Christmas Island is about 150 miles north of the equator and 1,340 miles south of Hawaii. The current El Niño is the strongest ever recorded, and it has hit this area harder than anywhere else on the planet.

When the Georgia Tech team visited the reefs last November, 50 to 90 percent of corals they saw were bleached and as many as 30 percent were already dead. This time, after months of warm waters powered by the El Niño, the numbers were starker. After extensive underwater surveys around the atoll, Baum’s team estimates that 80 percent of the corals are dead and 15 percent are bleached. Only 5 percent are still alive and healthy.

“To see the reefs change this dramatically in just a few months is shocking,” says Baum. “We were bracing ourselves for the worst, but seeing it with our own eyes was surreal. Christmas Island’s coral reefs are like ghost towns now. The structures are all still there, but no one is home.”

STARVING CORALS

Corals are communities of animals that have tiny photosynthetic algae living inside them in a mutually beneficial relationship. The algae provide corals with their vibrant corals, along with a vital source of food via photosynthesis. Corals, in turn, provide the structure that shelters their tiny algal symbionts.

Corals are very temperature-sensitive. A rise of just 1-1.5 degrees Celsius can stress coral enough to evict the algae until the heat stress subsides. This leaves a ghostly white coral skeleton and is known as “bleaching.” During protracted warm water events, such as the current El Niño, bleached corals aren’t able to bring their symbiotic plants back in, and they can die of starvation.

Temperatures on Christmas Island have been between 1.5 to 3 degrees Celsius higher than normal for the past 10 months straight. “This intense heat stress has transformed some of the world’s healthiest coral reefs into graveyards,” says Baum. “To our knowledge, this is the greatest coral mass mortality event at a single location on record.”

‘A WAKE-UP CALL’

Many other areas in the world’s oceans are also showing extensive bleaching this year, including Australia’s Great Barrier Reef, but the Christmas Island corals were pushed far beyond bleaching.

Cobb and Baum think it may take a decade or more for the Christmas Island reefs to recover, but they might never look the same because of warmer-than-average temperatures and lower ocean acidity. Both are the consequences of rising greenhouse gases.

“Aside from their sheer beauty and appeal, coral reefs provide a host of ecosystem services that are critical to a healthy ocean,” says Cobb. “When remote reefs like Christmas Island succumb to acute temperature stress, it’s a wake-up call for the rest of the world’s reefs, which will come under increasing stress from climate change.”

“Christmas Island’s people rely on the reefs for their food and their livelihoods, so they’ll be profoundly affected by this event,” says Baum. She and her team will be studying the reefs carefully over the coming years to assess the recovery and learn more about how some corals are managing to resist heat damage. At the same time, Cobb and her students will work to determine whether the record-breaking 2015/2016 El Niño event is a portent of future El Niño events under continued climate change.

“Our research will provide important new insights into how corals may be able to survive more frequent temperature extremes over the next century,” says Baum. “In the meantime, this event is a vivid reminder that the effects of climate change are happening now, and that the choices we make about greenhouse gas emissions in the next decades will have long-term effects.”

Source: Republished from Futurity.org as a derivative work under the Attribution 4.0 International license. Original article posted to Futurity by .

Featured Photo Credit: Georgia Tech

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Lack of Milkweed May Not Be the Source of Monarch Decline

Scientific dogma blames the population decline of monarch butterflies on a lack of milkweed, herbicides, and genetically modified crops, a view that a recent monarch study that was reported here on Science Rocks My World supported. A new study, however, casts a wider net: sparse autumnal nectar sources, weather, and habitat fragmentation.

“Thanks to years of data collected by the World Wildlife Fund and citizen-scientists across North America, we have pieced together the monarch life cycle to make inferences about what is impacting the butterflies,” says Anurag Agrawal, professor of ecology and evolutionary biology at Cornell University and senior author of a paper in the journal Oikos.

The scientists did not find evidence supporting the “milkweed-limitation hypothesis” during the monarch’s summer breeding season in the midwestern and northeastern United States. Rather, through statistical analyses, the group found problems in the transition from the US and southern Canada to the overwintering grounds in Mexico.

Milkweed is only a food source for the caterpillars in summer, not as the butterflies leave for their epic southern migration in autumn. The study finds that a “lack of milkweed, the only host plant for monarch butterfly caterpillars, is unlikely to be driving the monarch’s population decline, as the problem appears to occur after they take flight in the fall,” says Agrawal.

In any given year, four generations of monarch butterflies traverse much of North America over a 2,000-mile trek beginning in early spring when they leave the Mexican wintering grounds. In the first generation, millions of monarchs flow through Texas and Oklahoma, with the subsequent generations moving into the Midwest and Northeast, until the start of fall, when the fourth generation returns to the mountainous, high-altitude Oyamel fir forests of central Mexico.

Despite the seemingly good news of annual population bounce-back on the return from the south each year, the scientists were clear that the monarch population has been dwindling. Yes, says Agrawal: “The consistent decline at the overwintering sites in Mexico is cause for concern. Nonetheless, the population is six times what it was two years ago, when it was at its all-time low.”

Agrawal credits the population rebound to improved weather and release from the severe drought in Texas.

Agrawal says that a persistent decline caused by lack of nectar sources or other threats such as habitat loss or insecticide use can conspire with large annual population fluctuations—mostly due to weather—and may eventually push monarchs to dangerously low numbers.

“Given the intense interest in monarch conservation, the blame being put on herbicide use and the national dialogue about potentially listing monarchs under the endangered species act, we have to get the science right,” says Agrawal.

Hidetoshi Inamine, a graduate student in the field of the ecology and evolutionary biology, is lead author of the paper. Other authors are from Cornell and the North American Butterfly Association. Cornell’s Atkinson Center for a Sustainable Future funded the work, which is published in the journal Oikos.

Source: Republished from Futurity.org as a derivative work under the Attribution 4.0 International license. Original article posted to Futurity by .

Featured Photo Credit:  wildlife007/Flickr, CC BY 2.0

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This Stretchy Material Heals Itself and Twitches Like Muscle Tissue

Jolting a super-stretchy, self-healing material with an electrical field causes it to twitch or pulse in a muscle-like fashion. The polymer can also stretch to 100 times its original length, and even repair itself if punctured.

Cheng-Hui Li, working in the Stanford University lab of chemical engineering professor Zhenan Bao, wanted to test the stretchiness of a rubberlike type of plastic known as an elastomer that he had just synthesized. Such materials can normally be stretched two or three times their original length and spring back to original size. One common stress test involves stretching an elastomer beyond this point until it snaps.

But Li, a visiting scholar from China, hit a snag: The clamping machine typically used to measure elasticity could only stretch about 45 inches. To find the breaking point of their one-inch sample, Li and another lab member had to hold opposing ends in their hands, standing further and further apart, eventually stretching a 1-inch polymer film to more than 100 inches.

Bao was stunned.

“I said, ‘How can that be possible? Are you sure?’” she recalls.

In the journal Nature Chemistry, the researchers explain how they made this super-stretchy substance. They also showed that they could make this new elastomer twitch by exposing it to an electric field, causing it to expand and contract, making it potentially useful as an artificial muscle.

SELF-HEALING IN THE COLD

Artificial muscles currently have applications in some consumer technology and robotics, but they have shortcomings compared to a real bicep, Bao says. Small holes or defects in the materials currently used to make artificial muscle can rob them of their resilience. Nor are they able to self-repair if punctured or scratched.

But this new material, in addition to being extraordinarily stretchy, has remarkable self-healing characteristics. Damaged polymers typically require a solvent or heat treatment to restore their properties, but the new material showed a remarkable ability to heal itself at room temperature, even if the damaged pieces are aged for days. Indeed, researchers found that it could self-repair at temperatures as low as negative 4 degrees Fahrenheit (-20 C), or about as cold as a commercial walk-in freezer.

The team attributes the extreme stretching and self-healing ability of their new material to some critical improvements to a type of chemical bonding process known as crosslinking. This process, which involves connecting linear chains of linked molecules in a sort of fishnet pattern, has previously yielded a tenfold stretch in polymers.

First they designed special organic molecules to attach to the short polymer strands in their crosslink to create a series of structure called ligands. These ligands joined together to form longer polymer chains—spring-like coils with inherent stretchiness.

Then they added to the material metal ions, which have a chemical affinity for the ligands. When this combined material is strained, the knots loosen and allow the ligands to separate. But when relaxed, the affinity between the metal ions and the ligands pulls the fishnet taut. The result is a strong, stretchable and self-repairing elastomer.

“Basically the polymers become linked together like a big net through the metal ions and the ligands,” Bao explains. “Each metal ion binds to at least two ligands, so if one ligand breaks away on one side, the metal ion may still be connected to a ligand on the other side. And when the stress is released, the ion can readily reconnect with another ligand if it is close enough.”

ARTIFICIAL MUSCLE AND SKIN?

The team found that they could tune the polymer to be stretchier or heal faster by varying the amount or type of metal ion included. The version that exceeded the measuring machine’s limits, for example, was created by decreasing the ratio of iron atoms to the polymers and organic molecules in the material.

The researchers also showed that this new polymer with the metal additives would twitch in response to an electric field. They have to do more work to increase the degree to which the material expands and contracts and control it more precisely. But this observation opens the door to promising applications.

In addition to its long-term potential for use as artificial muscle, this research dovetails with Bao’s efforts to create artificial skin that might be used to restore some sensory capabilities to people with prosthetic limbs. In previous studies her team has created flexible but fragile polymers, studded with pressure sensors to detect the difference between a handshake and a butterfly landing. This new, durable material could form part of the physical structure of a fully developed artificial skin.

“Artificial skin is not just made of one material,” says Franziska Lissel, a postdoctoral fellow in Bao’s lab and member of the research team. “We want to create a very complex system.”

Even before artificial muscle and artificial skin become practical, this work in the development of strong, flexible, electronically active polymers could spawn a new generation of wearable electronics, or medical implants that would last a long time without being repaired or replaced.

The Air Force Office of Scientific Research, Samsung Electronics, and the Major State Basic Research Development Program of China supported the work at Stanford. Other members of the research team are from University of California, Riverside and University of Colorado, Boulder.

Source: Republished from Futurity.org as a derivative work under the Attribution 4.0 International license. Original article published to Futurity by .

Featured Image Credit:  Bao Research Group/Stanford

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[Video] This Octopus has an Odd Way of Grabbing a Meal

Unlike most octopuses, which tackle their prey with all eight arms, a rediscovered tropical octopus subtly taps its prey on the shoulder and startles it into its arms.

“I’ve never seen anything like it,” says Roy Caldwell, professor of integrative biology at the University of California, Berkeley. “Octopuses typically pounce on their prey or poke around in holes until they find something.

“When this octopus sees a shrimp at a distance, it compresses itself and creeps up, extends an arm up and over the shrimp, touches it on the far side, and either catches it or scares it into its other arms.”

BEAK-TO-BEAK MATING

The creature, known as the larger Pacific striped octopus, also turns out to be among the most gregarious of known octopuses. While most species are solitary, these have been seen in groups of up to 40 off the Pacific coasts of Nicaragua and Panama.

And while male octopuses typically share sperm with females at arm’s length, ready to flee should the female get aggressive or hungry, mating pairs of this octopus when observed in captivity sometimes cohabit in the same cavity for at least a few days while mating, with little indication of escalated aggression.

A mating pair of larger Pacific striped octopus; the male is the darker of the two. Just under the female’s eye and to the left of her funnel, the male’s mating arm (hectocotylus) enters her mantle cavity. The white object is a packet of the male’s sperm being passed down the hectocotylus to be deposited into the female’s mantle cavity. (Credit: Roy Caldwell) Click/Tap for larger image.
A mating pair of larger Pacific striped octopus; the male is the darker of the two. Just under the female’s eye and to the left of her funnel, the male’s mating arm (hectocotylus) enters her mantle cavity. The white object is a packet of the male’s sperm being passed down the hectocotylus to be deposited into the female’s mantle cavity. (Credit: Roy Caldwell) Click/Tap for larger image.

Mating pairs have even been observed to share meals in an unusual beak-to-beak position. They do engage in rough sex, however. The pair grasp each other’s arms sucker-to-sucker and mate beak-to-beak, as if kissing. The females mate frequently and lay eggs over several months, whereas the females of most known octopuses die after a single brood.

“HARLEQUIN” OCTOPUSES

The peculiar behaviors seen in the larger Pacific striped octopus are actually a testament to how little is known about most octopuses. While their behavior and neurobiology have been extensively studied, most research is based on observations of just a handful of the more than 300 species of octopus worldwide, Caldwell says.

“There are a lot of species of octopus, and most have never even been seen alive in the wild and certainly haven’t been studied.”

Panamanian biologist Arcadio Rodaniche first observed much of this strange behavior in the 1970s while studying captured specimens in a saltwater swimming pool in Panama. The behavior was so at odds with accepted octopus behavior, however, that he was unable to publish more than an abstract. The species has still not been officially described and has no scientific name.

Caldwell, too, once doubted the brief description of the octopus’s behavior, and only stumbled across the species while pursuing a smaller relative, Octopus chierchiae, on the Pacific coast of Central America. Both are “harlequin” octopuses, so called because of their semi-permanent stripes and spots. The animal lives in water between 40 and 50 meters (150 feet) deep, typically on muddy, sandy plains at the mouths of rivers, probably living in cast-off shells or rock cavities. Females grow to less than 7 centimeters across (3 inches), while males max out at less than 4.5 centimeters (2 inches).

‘DENIZENS OF THE DEEP’

For a new study, published in the journal PLOS ONE, Caldwell and coauthor Richard Ross of the California Academy of Sciences obtained 24 live specimens from a pet supplier between 2012 and 2014 and observed them in their laboratories. Ross even put some on display at the academy’s Steinhart Aquarium, where guests could have observed several pairs mating daily and producing multiple clutches of eggs.

“Personally observing and recording the incredibly unique cohabitation, hunting, and mating behaviors of this fascinating octopus was beyond exciting—almost like watching cryptozoology turn into real-life zoology,” Ross says. “It reminds us how much we still have to learn about the mysterious world of cephalopods.”

“Each time a different type of octopus is studied, we need to redefine our theories about their behavior. It turns out most don’t live up to their ‘denizen of the deep’ reputation,” says former UC Berkeley doctoral student Christine Huffard of the Monterey Bay Aquarium Research Institute.

In these captive environments, the biologists observed females laying eggs for up to six months and brooding for up to eight months. Even after their eggs began hatching, females continued to feed, mate, and lay hundreds more eggs—another unusual behavior.

The larger Pacific striped octopus exhibits a striking high-contrast display of colors and patterns, which can vary from a pale to dark reddish-brown hue to black with white stripes, and spots with both smooth and uneven skin textures.

“They certainly respond to one another when they display their highly contrasting stripes and spots, so their coloration appears to be useful for group living,” Caldwell says. “Nevertheless, while they tolerate one another and sometimes pair up, I don’t think they are highly social.

“Only by observing the context in which these behaviors occur in the wild can we begin to piece together how this octopus has evolved behaviors so radically different from what occurs in most other species of octopus,” he says.

Source: Republished from Futurity.org as a derivative work under the Attribution 4.0 International license. Original article posted to Futurity by .

Featured Photo Credit: Roy Caldwell

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Explainer: what is the gut microbiota and how does it affect mind and body?

By Senaka Ranadheera, Victoria University; Deborah Hodgson, University of Newcastle, and Javad Barouei, University of California, Davis.

The human gastrointestinal tract harbours trillions of microorganisms, consisting of up to 1,000 or so different bacterial species.

These bacteria, known collectively as the gut microbiota, perform a number of vital functions in our body. They defend against pathogens, aid in digestion and nutrient absorption, produce vitamins (K and B), and boost our immune system.

The gut microbiota also has the potential to influence our brain development and behaviour. Our gut and the central nervous system constantly communicate with each other by releasing signalling molecules. The gut microbiota is also involved in this communication process, known as the microbiota-gut–brain axis.

Our microbiota is unique

The composition of the gut microbiota is unique to each individual (even identical twins) and can be affected by many factors including diet, diseases and ageing.

Our gastrointestinal tract is nearly sterile at birth, but quickly transits to one with a diverse microbial community. The composition of this community depends on many factors, including:

  • the composition of our mother’s gut microbiota
  • the way we are born (vaginal or caesarean delivery)
  • our early diet (including being breast or formula fed as an infant)
  • early life events such as diseases and stress
  • the use of antibiotics and other medications
  • hygiene conditions
  • the environment.

By the age of three, the gut microbiota stabilises, and its evolution continues at a steadier rate during adulthood.

How gut imbalance affects the mood

An imbalance of beneficial versus harmful gut bacteria, known as “dysbiosis”, has been linked to a number of nervous system, gastrointestinal and psychological disorders.

Exposure to early life stress – including psychological, sexual and physical abuse – can increase the risk of gastrointestinal disorders later in life. The exact reason is unknown but it may be because the establishment of stable gut microbiota is disrupted.

Stress and psychological factors can make these functional gastrointestinal disorders worse. A recent animal study showed that as little as two hours of stress was enough to change the composition of gut microbiota.

Another study showed two weeks of stress could influence the changes in the gut microbiota composition as well as induce some anxiety-related behaviour in mice. Researchers found a correlation between specific elements of anxiety-related behaviour and elements of the gut microbiota.

Research also shows that people suffering from gastrointestinal disorders are more susceptible to anxiety-related disorders such as post-traumatic stress disorder.

Although the underlying mechanism is not fully understood as yet, there is clear evidence of a connection between the microbiota, gut and brain.

Role of probiotics

Probiotics are live microorganisms that have been delivering health benefits for thousands of years by helping to establish healthy gut microbiota. Lactobacillus and Bifidobacterium are the most commonly used probiotics.

The mechanisms responsible for the beneficial impact of probiotics on health are not well known, however accumulating evidence suggests they help colonization of the gut microbiota with beneficial microorganisms.

Treatment of functional gastrointestinal disorders with probiotics has yielded mixed results to date. This may be because not all probiotics are the same. And the same probiotic strain can exert different effects in different hosts.

However, probiotic therapy holds promise for future applications both in functional gastrointestinal disorders and psychiatric illness.

Of particular interest is a recently identified class of probiotics that have been categorised as “psychobiotics” due to their possible antidepressant or qualities. These have been shown to relieve anxiety in patients suffering from functional gastrointestinal disorders.

What else we can do?

While there is an obvious connection between gut microbiota and brain, scientists have more questions than answers about this complex relationship.

What we do know is that promoting the establishment of a healthy gut microbial community in early life is the best way to harness the power of the microbiota throughout life.

Breastfeeding is one of the most important practices to establish friendly gut microbiota in early life. Breastfed infants usually have healthier and more diverse gut microbiota than formula-fed infants. Breast milk also contains healthy microbial communities and materials that stimulate the growth of beneficial gut microbes and probiotics.

We can improve the gut microbiota composition as well as prevent many diseases by simply changing our diet. Modern Western meals are high in sugar and fat, and low in fibre, which may affect the establishment of beneficial gut microbiota.

Fibre-rich foods such as vegetables, fruits and whole-grain cereals are essential to promote the growth and activity of beneficial gut microbiota.

The ConversationSenaka Ranadheera, Early Career Research Fellow, Advanced Food Systems Research Unit, College of Health and Biomedicine, Victoria University; Deborah Hodgson, Pro Vice-Chancellor Research & Innovation, University of Newcastle, and Javad Barouei, Postdoctoral Researcher, Department of Food Science and Technology, University of California, Davis

This article was originally published on The Conversation. Read the original article.

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Astronomers Find a ‘Dark Galaxy’ Lurking in This Image

New analysis of an image taken by the ALMA telescope in Chile reveals evidence that a dwarf dark galaxy—a tiny halo companion of a much larger galaxy—is lurking nearly 4 billion light-years away.

This discovery paves the way for ALMA to find many more such objects, which could help astronomers address important questions on the nature of dark matter.

In 2014, as part of ALMA’s Long Baseline Campaign, astronomers studied a variety of astronomical objects to test the telescope’s new high-resolution capabilities. One of these experimental images was that of an Einstein ring, which was produced by a massive foreground galaxy bending the light emitted by another galaxy nearly 12 billion light-years away.

This phenomenon, called gravitational lensing, was predicted by Einstein’s theory of general relativity, and it offers a powerful tool for studying galaxies that are otherwise too distant to observe. It also sheds light on the properties of the nearby lensing galaxy because of the way its gravity distorts and focuses light from more distant objects.

LIKE RAIN DROPLETS ON A WINDOW

In a new paper accepted for publication in the Astrophysical Journal, astrophysicist Yashar Hezaveh at Stanford University and his team explain how detailed analysis of this image of a galaxy called SDP.81 uncovered signs of a hidden dwarf dark galaxy in the halo of a the more nearby galaxy.

Composite image of the gravitational lens SDP.81 showing the distorted image of the more distant galaxy (red arcs) and the nearby lensing galaxy (blue center object). (Credit: Y. Hezaveh/Stanford; ALMA/NRAO/ESO/NAOJ; NASA/ESA Hubble Space Telescope) Click/Tap for larger image.
Composite image of the gravitational lens SDP.81 showing the distorted image of the more distant galaxy (red arcs) and the nearby lensing galaxy (blue center object). (Credit: Y. Hezaveh/Stanford; ALMA/NRAO/ESO/NAOJ; NASA/ESA Hubble Space Telescope) Click/Tap for larger image.

“We can find these invisible objects in the same way that you can see rain droplets on a window: You know they are there because they distort the image of the background objects,” explains Hezaveh.

In the case of a raindrop, the image distortions are caused by refraction, but here similar distortions are generated by the gravitational influence of dark matter, according to Einstein’s theory of relativity.

Current theories suggest that dark matter, which makes up 80 percent of the mass of the universe, is made of as-yet-unidentified particles that don’t interact with visible light or other forms of electromagnetic radiation. Dark matter does, however, have appreciable mass, so it can be identified by its gravitational influence.

For their analysis, the researchers harnessed thousands of computers working in parallel for many weeks, including the National Science Foundation’s most powerful supercomputer, Blue Waters, to search for subtle anomalies that had a consistent and measurable counterpart in each “band” of radio data.

From these combined computations, the researchers were able to piece together an unprecedented understanding of the lensing galaxy’s halo, the diffuse and predominantly star-free region around the galaxy, and discovered a distinctive clump, less than one-thousandth the mass of the Milky Way.

THOUSANDS IN THE MILKY WAY

Because of its relationship to the larger galaxy, its estimated mass and lack of an optical counterpart, the astronomers believe this gravitational anomaly may be caused by an extremely faint, dark-matter dominated satellite of the lensing galaxy. According to theoretical projections, most galaxies should be brimming with similar dwarf galaxies and other companion objects.

Detecting them, however, has proven challenging. Even in our own Milky Way, astronomers can identify only about 40 of the thousands of satellite dwarfs that are predicted to be present.

Computer models of the evolution of the universe indicate that if the number of small dark matter clumps around distant galaxies, like the one detected here, is significantly lower than predictions, this would imply that the dark matter particles have a warm temperature.

Risa Wechsler, an associate professor of physics at Stanford, and graduate student Yao-Yuan Mao used these computer simulations to show that so far this detection is consistent with the predictions of the cold dark matter theoretical model. More observations are needed, however, to definitively rule out the possibility of a warm temperature for dark matter.

“This detection is very exciting—it shows that we finally have a tool to find these dwarf satellites efficiently in a way that was not possible before,” says Wechsler. “Now we need to look at other galaxies to hopefully find more of these small dark halos to have a statistically significant test of the cold dark matter predictions.”

The finding is an exciting demonstration of the power of ALMA, said astrophysicist Roger Blandford, the a professor in the School of Humanities and Science at Stanford, who was involved in the research. “This discovery proves that ALMA can be used to provide valuable new insights into the physics of dark matter.”

Source: Republished from Futurity.org as a derivative work under the Attribution 4.0 International license. Original article posted to Futurity by .

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How Deep-Sea Creatures Survived the Dino-Killer Asteroid

Deep-sea creatures were able to survive the catastrophic asteroid strike that wiped out the dinosaurs 65 million years ago thanks to tiny algae that supplied a slow but steady trickle of food to the ocean floor.

Like the dinosaurs themselves, giant marine reptiles, invertebrates, and microscopic organisms became extinct after the catastrophic asteroid impact in an immense upheaval of the world’s oceans, but, somehow, deep-sea creatures managed to survive.

Their survival has puzzled scientists since it has been widely believed that the asteroid impact cut off the food supply in the oceans by destroying free-floating algae and bacteria.

But, now, new research by oceanic scientists from Cardiff University offers strong evidence suggesting that some forms of algae and bacteria were actually living in the aftermath of the asteroid disaster, and that they acted as a constant, sinking, slow trickle of food for creatures living near the seafloor.

The findings, published in the journal, Geology, are a result of an analysis of the chemical composition of the fossilized shells of sea surface and seafloor organisms from that period, taken from drilling cores from the ocean floor in the South Atlantic.

This gave the researchers an idea of the flux, or movement, of organic matter from the sea surface to the seafloor in the aftermath of the asteroid strike, and led them to conclude that a slow trickle of food was constantly being delivered to the deep ocean.

Furthermore, the team were able to calculate that the food supply in the ocean was fully restored around 1.7 million years after the asteroid strike, which is almost half the original estimate, showing that marine food chains bounced back more quickly than originally thought.

“The global catastrophe that caused the extinction of the dinosaurs also devastated ocean ecosystems. Giant marine reptiles met their end as did various types of invertebrates such as the iconic ammonites,” says Heather Birch, a PhD student at the School of Earth and Ocean Sciences at Cardiff University.

“Our results show that despite a wave of massive and virtually instantaneous extinctions among the plankton, some types of photosynthesizing organisms, such as algae and bacteria, were living in the aftermath of the asteroid strike.

“This provided a slow trickle of food for organisms living near the ocean floor which enabled them to survive the mass extinction, answering one of the outstanding questions that still remained regarding this period of history.

“Even so, it took almost two million years before the deep-sea food supply was fully restored as new species evolved to occupy ecological niches vacated by extinct forms.”

Many scientists currently believe that the mass extinction of life on Earth around 65 million years ago was caused by a 10 kilometer wide asteroid that hit Mexico’s Yucatán Peninsula. It is believed the debris from impact starved the Earth of the Sun’s energy and, once settled, led to greenhouse gases locking in the Sun’s heat and causing temperatures to rise drastically.

This period of darkness followed by soaring heat, known as the Cretaceous-Paleogene boundary, was thought to obliterate almost half of the world’s species.

Scientists also claim that the impact of the asteroid would have filled the Earth’s atmosphere with sulphur trioxide, subsequently creating a gas cloud that would have caused a mass amount of sulphuric acid rain to fall in just a few days, making the surface of the ocean too acidic for upper ocean creatures to live.

The team’s research was published in the journal Geology.

Source: Republished from Futurity.org as a derivative work under the Attribution 4.0 International license. Original article posted to Futurity by .

Featured Photo Credit:  Ryan Somma/Flickr, CC BY-SA 2.0

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This Vocal Pattern is Shared by Monkeys and People [Audio]

The long, complex vocal sequences of monkeys living in Ethiopia follow a pattern seen in many human languages: the longer the overall sequence, the shorter the sounds within it.

The linguistic pattern in humans is known as Menzerath’s law. According to the law, longer words tend to be made up of shorter syllables and longer phrases are usually made up of shorter words. The law had never been tested in the vocal communication of any other species.

Researchers led by Morgan Gustison, a University of Michigan doctoral student in psychology, and Stuart Semple, a professor of evolutionary anthropology at the University of Roehampton, tested this law in geladas, a species in which males produce long sequences of different calls—up to 25 calls in all—made up of six different call types.

They analyzed 1,065 of these vocal sequences (composed of 4,747 individual calls) recorded from 57 males living in the Sankaber area of the Simien Mountains National Park, Ethiopia.

The researchers found a negative relationship between the sequence length in terms of the number of calls, and the mean duration of the constituent calls. Calls did not vary in length according to their position in the vocal sequence.

The length of the first calls in sequences was closely related to how long the total sequence was. In other words, sequences started off with calls of the “appropriate” length for that sequence: short sequences started with long calls and long sequences started with short calls.

“The findings of this work not only reveal a basic pattern of sequence structure shared by human and nonhuman animal communication, but may also have profound implications for our understanding of biological systems more broadly,” Gustison says.

Other researchers include Ramon Ferrer-i-Cancho at Universitat Politècnica de Catalunya in Spain and Thore Bergmann at the University of Michigan.

The findings appear in the Proceedings of the National Academy of Sciences.

Source: Republished from Futurity.org as a derivative work under the Attribution 4.0 International license. Original article posted to Futurity by .

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New Study of Snails Suggests that Indeed Sex May Have its Perks

A team lead by biologist Maurine Neiman of the University of Iowa had published a study in early 2016 indicating that a New Zealand snail seemingly made a case for sex being almost pointless.  This same team has now found that there indeed may be a very good point for sexual vs. asexual reproduction in this snail species (Potamopyrgus antipodarum), indicating that male-female mating—factored over generations—helps creatures keep pace with an ever-changing world and fend off threats, which may perhaps broadly be applicable to all species.

In this new study, researchers documented the concentration of sexual females and asexual females at multiple sites in the same lake and compared how their populations were affected by a parasitic worm commonly associated with the snails.

In areas of the lake where the worm was prevalent, male snails were plentiful (indicating sexually reproducing female snails were present). The researchers also found male snails roaming in areas where the parasite concentration was as low as four percent, as well as in higher numbers where parasite activity was heavier.

The results offer another encouraging sign that sexually produced offspring are getting a genetic boost from mommy and daddy. For instance, the offspring get two genetic blueprints (one from each parent), rather than just their mother’s genome, which they would if they were born to an asexual female.

Viewed over generations, sexual reproduction can produce new gene combinations that are needed to deal with changing environments.

“These results are consistent with the idea that there are advantages to sex related to the ability to produce diverse offspring,” says Maurine Neiman, associate professor in biology at the University of Iowa and corresponding author on the paper published in the New Zealand Journal of Ecology. “Snails born with rare gene combinations would be harder to infect because the parasites have rarely, if ever, encountered those shuffled genetic combinations.”

Neiman and others in her field have been studying the freshwater snails for years, in large part because some females can bear offspring without males. The snails also are vulnerable to a well-documented threat—a parasitic worm (Microphallus livelyi) that lives within the snail as it awaits a chance to glom on to its final host: ducks that eat infected snails.

Previous studies have shown an association between parasite concentration and the number of sexual female snails. Where parasite activity is low, sexual females are few; where parasite activity is high, sexual females are abundant.

This study adds to other analyses linking parasite activity to sexual and asexual female populations within a small mountain lake, Lake Grasmere. This study is distinctive because the researchers found dramatic differences in the percentage of female sexual and asexual snails (using males’ presence as a proxy) and parasite prevalence between sites as close as two football fields apart, “suggesting that these evolutionary links between sex and parasites can operate at a remarkably small scale,” Neiman says.

Neiman and her colleagues think the parasitic worm invades the snail by tricking its immune system into believing it’s not a threat. Some diseases do the same with humans, fooling our immune system just enough to lodge themselves within our bodies and make us ill. Yet, over time, humans have inherited and passed down new gene combinations that protect better against those diseases. That’s genetic diversity and natural selection at work.

Like humans, the snails’ best defense against the parasitic worm is to pass down gene combinations that are new to the parasite. That shuffling of genes is much more likely to occur through male-female mating than asexual reproduction, where the daughter inherits her mother’s exact genetic makeup.

The team visited Lake Grasmere in January 2014. There, 25 undergraduates from Carleton College, in Minnesota, assisted Neiman and the paper’s first author, Carleton College biologist Mark McKone, by collecting 1,800 snails at 18 sites, either on foot or by kayak, and examining each under a microscope to catalog sex and infection rates. Carleton College funded the study, which is published in the New Zealand Journal of Ecology.

Source: Republished from Futurity.org as a derivative work under the Attribution 4.0 International license. Original article posted to Futurity by . 

Featured Image Credit: Bart Zjilstra

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Brazil’s thriving soy industry threatens its forests and global climate targets

By Peter Richards, Brown University and Jeffrey Hoelle, University of California, Santa Barbara.

Brazil’s economy is teetering on the edge of collapse. The country’s political regime has been rocked by recent corruption scandals, and impeachment proceedings are encircling the nation’s leaders. And yet things couldn’t be much better for Brazil’s soybean farmers.

At the beginning of the last decade, Brazil emerged as a major soybean exporter. Today, Brazil produces about one-third of the global supply and earns more from soybean exports than from any other commodity.

Although soybean production is generating revenues for Brazil, it could spell trouble for the nation’s widely lauded environmental commitments.

Brazil is the first emerging economy that has pledged to make absolute reductions in its greenhouse gas emissions – that is, reductions from the level that it emitted at a specific point in time (2005), not from an estimate of what it will emit at some future time. Its climate plan calls for cutting emissions by more than 40 percent by 2030, with most of its emission reductions to come through avoiding deforestation. By 2030, Brazil has pledged to restore 12 million hectares of carbon-absorbing forest and eliminate illegal deforestation.

As social science researchers who study environmental change in the Amazon and the Brazilian savanna known as the Cerrado, we have seen the country’s agricultural sector grow rapidly in once-marginal regions. We believe that over the next several years, with Brazil’s soybean sector thriving and its political establishment in crisis, the nation’s commitment to slowing climate change will be severely tested.

Why economic downturns are good for soy farmers

Tough economic times for Brazil can mean boom times for soybean farmers. Soybean prices in Brazil generally depend on two factors: the global price for soybeans, and the value of the local currency (the real) against the U.S. dollar.

Obviously, a high global price for soybeans means more money for farms. However, the importance of the local currency is even more critical for farmers’ bottom lines. Commodities like soybeans are priced in dollars but purchased in local currency, so when the Brazilian real is weak, farmers receive more value (in local terms) for their harvest and earn higher profits.

This dynamic creates a paradoxical relationship between Brazil’s agriculture sector and the national economy: when the economy struggles, farmers reap big profits. In the early 2000s, when the real fell to one-third of its value over a three year period, soybean profits jumped to stratospheric levels.

In response, farmers converted an area equivalent to the size of Indiana to soybean production. In some areas cropland prices nearly tripled.

Brazil’s current economic collapse is once again creating windfall conditions for soybean farmers. Over the past year and a half, the cracks in the country’s economy have become rifts and the real has lost more than one-third of its value. The farther the currency falls, the higher soybean prices rise. From 2011 to 2016, soybean prices increased by 70 percent, peaking in January 2016.

Percent change in soybean prices, and the value of Brazil’s currency, since 2011. Soybean prices in Brazil have surged to near-record levels, even as prices, in terms of U.S. dollars, have declined. http://cepea.esalq.usp.br/soja/

In local terms, we estimate that the value of this year’s harvest will be more than one-third larger than the harvest just two years ago. The U.S. Department of Agriculture projects that this year Brazil will produce nearly as many soybeans as the United States, an output that was unthinkable even just a few years ago.

Soybeans are generating valuable foreign exchange, new investment capital and high-wage jobs, all of which Brazil critically needs. As the farm sector’s economic clout increases, so does its political influence. Earlier this year during Carnival celebrations in Rio de Janeiro, in a procession seemingly transplanted from a U.S. state fair, dancers dressed as cotton, corn and soybeans paraded through the streets and were “harvested” by a giant float in the shape of an agricultural combine.

Agricultural display at Carnival

Brazil’s agriculture lobby is gaining ground as President Dilma Roussef’s Partido dos Trabalhadores (Workers Party) disintegrates in a wave of corruption scandals. We believe government support for enacting new environmental regulations and enforcing existing environmental laws is already fading.

Forests at risk

After the international community and Brazil’s domestic environmental groups denounced large-scale deforestation in the Amazon in the early 2000s, the government adopted a battery of reforms to reduce forest losses.

Enormous new forest reserves were created and indigenous reserves were expanded. New environmental regulations were enacted to inhibit clearings for cattle pastures and soybean farms. Private agribusinesses worked with environmental advocacy groups, intervening in the soybean and cattle supply chains to discourage land clearing, especially for soybean production.

Evidence suggests that these measures worked. Deforestation fell from nearly 30,000km² in 2004 to less than 5,000km² in 2012. But next year the incentive to clear land will be greater than it has been in a decade. Windfall profits from this year’s soybean harvest will give landowners both the incentive to purchase or clear land and the capital that they need to do so.

Early signs of a new wave of deforestation in the Amazon are already appearing. Late last year the Brazilian government released data that showed a 16 percent increase in tree destruction over 2014 levels. The largest increases in forest loss were recorded in Brazil’s leading soybean-producing state, Mato Grosso.

The next several years could well pose a breaking point for Brazil’s economy, which currently is being held together by the country’s booming agriculture sector. In turn, further expansion of agriculture could derail Brazil’s climate commitments.

For most of this decade Brazil has received tremendous acclaim for its environmental actions. Brazil also stands ready to sign the climate change agreement negotiated late last year in Paris. But the country’s ability and will to follow through on those commitments has never been in such doubt.

The ConversationPeter Richards, Postdoctoral Fellow, Brown University and Jeffrey Hoelle, Assistant Professor of Anthropology, University of California, Santa Barbara

This article was originally published on The Conversation. Read the original article.

Featured Image Credit:  Agência Brasil, CC BY-3.0 BR

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