Volcanoes Played Role In Ancient Ice Age, Mass Extinction

Researchers here have discovered the pivotal role that volcanoes played in a deadly ice age 450 million years ago.

Perhaps ironically, these volcanoes first caused global warming -- by releasing massive amounts of carbon dioxide into the atmosphere.

When they stopped erupting, Earth’s climate was thrown off balance, and the ice age began.

The discovery underscores the importance of carbon in Earth’s climate today, said Matthew Saltzman, associate professor of earth sciences at Ohio State University.

The results will appear in the journal Geology, in a paper now available online.

Previously, Saltzman and his team linked this same ice age to the rise of the Appalachian Mountains. As the exposed rock weathered, chemical reactions pulled carbon from Earth’s atmosphere, causing a global cooling which ultimately killed two-thirds of all species on the planet.

Now the researchers have discovered the other half of the story: giant volcanoes that formed during the closing of the proto-Atlantic Ocean -- known as the Iapetus Ocean -- set the stage for the rise of the Appalachians and the ice age that followed.

“Our model shows that these Atlantic volcanoes were spewing carbon into the atmosphere at the same time the Appalachians were removing it,” Saltzman explained. “For nearly 10 million years, the climate was at a stalemate. Then the eruptions abruptly stopped, and atmospheric carbon levels fell well below what they were in the time before volcanism. That kicked off the ice age,” he said.

This is the first evidence that a decrease in carbon from volcanic degassing -- combined with continued weathering of the Appalachians -- caused the long-enigmatic glaciation and extinction in the Ordovician period.

Here is the picture the researchers have assembled: 460 million years ago, during the Ordovician, volcanoes along the margin of what is now the Atlantic Ocean spewed massive amounts carbon dioxide into the atmosphere, turning the world into a hothouse. Lava from those volcanoes eventually collided with North America to form the Appalachian Mountains.

Acid rain -- rich in carbon dioxide -- pelted the newly exposed Appalachian rock and wore it away. Chemical reactions trapped the carbon in the resulting sediment, which formed reefs in the vast seas that covered North America.

For about 10 million years, the volcanoes continued to add carbon to the atmosphere as the Appalachians removed it, so the hothouse conditions remained stable. Life flourished in the warm oceans, including abundant species of trilobites and brachiopods.

Then, 450 million years ago, the eruptions stopped. But the Appalachians continued weathering, and atmospheric carbon levels plummeted. The Earth swung from a hothouse to an icehouse.

By 445 million years ago, glaciers had covered the south pole on top of the supercontinent of Gondwana (which would eventually break apart to form the continents of the southern hemisphere). Two-thirds of all species had perished.

When they started this research, Saltzman and his team knew that Earth’s climate must have changed drastically at the end of the Ordovician. But they didn’t know for certain that volcanoes were the driving force, explained Seth Young, who did this research for his doctoral degree at Ohio State. He is now a postdoctoral researcher at Indiana University.

“This was not necessarily what we expected when we started investigating, but as we combined our data sources, the story began to fall into place,” Young said.

Using a computer model, they drew together measurements of isotopes of chemical elements -- including strontium from rocks in Nevada and neodymium from rocks in Virginia and Pennsylvania -- with measurements of volcanic ash beds in the same locations. Then they factored in temperature models developed by other researchers.

The ash deposits demonstrated when the volcanoes stopped erupting; the strontium levels indicated that large amounts of volcanic rock were being eroded and the sediment was flooding Earth’s oceans during this time; and the neodymium levels pinpointed the Appalachians as the source of the sediment.

The new findings mesh well with what scientists know about these ancient proto-Atlantic volcanoes, which are thought to have produced the largest eruptions in Earth’s history. They issued enough lava to form the Appalachians, enough ash to cover the far ends of the earth, and enough carbon to heat the globe. Atmospheric carbon levels grew 20 times higher than they are today.

This study shows that when those volcanoes stopped erupting, carbon levels dropped, and the climate swung dramatically back to cold. The timing coincides with today’s best estimates of temperature fluctuations in the Ordovician.

“The ash beds start building up at the same time the Appalachian weathering begins, but then the record of volcanism ends, and the temperature drops,” Saltzman said. “Knowing these details can help us understand how carbon in the atmosphere is changing Earth’s climate today.”

Next, the researchers will examine the role of the ancient volcanic ash more closely. While the ash was in the atmosphere -- before it settled around the globe -- it might have blotted out the sun, and cooled the earth somewhat. Saltzman and his team want to make some estimate of this short-term cooling effect to refine their computer model.

Meanwhile, Young is just starting to re-analyze the same rock samples, this time looking for a different isotope -- sulfur. This, he hopes, will offer clues to how much oxygen was in the oceans, and how that oxygen may have affected life in the Ordovician.

Other contributors to this work include Kenneth Foland, professor emeritus of earth sciences, and Jeff Linder, a research associate, both of Ohio State; and Lee Kump, professor of geosciences at Pennsylvania State University.

This research was partly supported by the National Science Foundation.

original story at http://www.redorbit.com/news/science/1775126/volcanoes_played_role_in_ancient_ice_age_mass_extinction/index.html

Exercise makes cigarettes less attractive to smokers

Source: University of Exeter

Exercise can help smokers quit because it makes cigarettes less attractive. A new study from the University of Exeter shows for the first time that exercise can lessen the power of cigarettes and smoking-related images to grab the attention of smokers. The study is published in the journal Addiction. The study involved 20 moderately heavy smokers, who had abstained from cigarettes for 15 hours before the trial. During two visits to our laboratory participants began by being shown smoking-related and neutral images, and then spent either 15 minutes sitting or exercising on a stationary bike at a moderate intensity. Afterwards, they were again shown the images.

While the participants were shown the images, the research team used the latest eye tracking technology to measure and record their precise eye movements. They were able to show not only the length of time people looked at smoking-related images but also how quickly pictures of cigarettes could grab their attention, compared with non-smoking matched images.

The study showed an 11% difference between the time the participants spent looking at the smoking-related images after exercise, compared with the after sitting. Also, after exercise, participants took longer to look at smoking-related images. Exercise, therefore, appears to reduce the power of the smoking-related images to grab visual attention.

Numerous studies have shown that a single session of light to moderate intensity exercise, for example five-15 minutes of brisk walking, can reduce cravings and responses to smoking cues. This is the first time eye-tracking technology has been used to show that exercise can reduce interest in and salience of smoking cues that, outside the laboratory, may cause lapses and relapse among smokers trying to quit.

Lead author, University of Exeter PhD student Kate Janse Van Rensburg said: "We know that smoking-related images can be powerful triggers for smokers who are abstaining. While we are no longer faced with advertisements for cigarettes, smokers are still faced with seeing people smoking on television, in photographs or in person. We know that this makes it more difficult for them to quit.

"Because of this, it's very exciting to find that just a short burst of exercise can somewhat reduce the power of such images. It is not clear if longer or more vigorous bouts of exercise have a bigger effect. This study adds to the growing evidence that exercise can be a great help for people trying to give up smoking."

How Galileo's spy glass upended science

Agence France-Presse

PARIS: It would hardly pass as a toy today, but the telescope Galileo used 400 years ago this week, overturned the foundations of knowledge, changing our perception of the universe and our place within it.

Galileo's 'optick tube' magnified a meagre nine-fold and was not even conceived of for astronomy.

Nevertheless, when the gadget was first demonstrated, Venetian senators were so smitten with its military potential that they doubled Galileo's salary and awarded him life tenure in the city-state's most prestigious university.

Paradigm shift

But when, in late October 1609, the 45-year-old Italian mathematician pointed his newfangled instrument - essentially two lenses aligned in a tube - skyward, what he glimpsed would unleash a scientific revolution and a rare paradigm shift in thought.

"He immediately made several surprising discoveries that contributed to the demise of the Earth-centred cosmology that had dominated Western thought for two millennia," says Robert Joseph, an astronomy at the University of Hawaii in Honolulu.

Using ever-more powerful telescopes over the next year, Galileo observed that the Moon was not perfectly smooth as claimed by Aristotle but cratered and mountainous.
He spotted hundreds of stars never seen before.

Galilean moons

More critically, he discovered the four inner satellites of Jupiter - still known as the "Galilean moons" today, in his honour - and learnt that Venus, Earth's closest planet, goes through a full range of phases.

Put together, his observations validated the revolutionary theory of Nicolaus Copernicus that Earth orbits the Sun, and not the other way round.

Galileo understood the implications of what he had seen, but the Catholic Church was not ready to accept such heresy. Only in 2000 did the Holy See apologise for putting Galileo on trial in 1633, forcing him to recant his ideas lest he face imprisonment or worse. The Vatican also paid tribute to him in an exhibition that opened this month.

But resistance to a solar-centric view was not only religious. The ancient Greek notion that Earth was at the centre of the cosmos was also a deeply ingrained scientific dogma, and it took decades to dislodge it.

Even the notion that "we can improve on our senses" by magnifying our vision was considered taboo, says Jerome Lamy, a science historian at the Paris Observatory in France.

Scientific revolution

The concept of paradigm shifts was first articulated by U.S. philosopher Thomas Kuhn in a 1962 book, "The Structure of Scientific Revolutions". A sea change in thinking entails not only the overturning of a theory but the creation of an entirely new world view, he said.

It happened again at the start of the 20th century, only a few years after Scottish mathematician Lord Kelvin had famously declared there was "nothing new" to be discovered in physics.

That seismic shift came in the form of a short paper on special relativity by a German-born patent clerk by the name of Albert Einstein.

Again, it did not happen overnight. But Einstein's ideas eventually toppled laws of physics that had prevailed for three centuries.

The God particle

Some scientists say that we may be on the edge of yet another such turning point as the world's biggest atom smasher, the Large Hadron Collider (LHC), gears up to search for a theoretical sub-atomic particle that could explain how matter acquires mass.

Dark matter and dark energy, deemed to account for 96% of the cosmos are other theorised puzzles. If the LHC answers them, it could once again throw science into a period of fruitful crisis before a new consensus emerges.

German nuclear physicist Max Planck understood that old theories die hard. "A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die," he wrote.

Story on this link

http://www.cosmosmagazine.com/news/3094/how-galileos-spy-glass-upended-science?page=0,0

Why Fat Lubricates Your Appetite

By Frederik Joelving

When you've spent the weekend splurging on greasy fast foods, your bathroom scale isn't alone in reeling from the impact. Your brain does, too. New research shows just how saturated fat tricks us into eating more and elucidates the evolutionary basis for the propensity for poundage in developed nations. Our brain physiology, it seems, is glaringly out-of-date in the modern world.

Researchers have long known that the hormones leptin and insulin play key roles in appetite and food intake. In healthy people leptin, which is secreted by fat tissue, acts as a molecular measuring tape for our waistlines, quashing feelings of hunger. Insulin spikes when the pancreas gets a whiff of the blood sugar increase after a meal; once the brain detects the spike, it knows to tamp down the desire for food.

Certain foods and metabolic disorders, however, can disrupt our ability to respond appropriately to these hormonal signals. In a study published in the September issue of The Journal of Clinical Investigation, scientists report unraveling a central biochemical mechanism behind fat's effect on the mammalian brain . They found that after only three days on a diet high in saturated fat—a common ingredient in beef and cheese—the brains of rats and mice became resistant to leptin and insulin. In contrast, unsaturated fats, such as those found in olive oil, did not trigger resistance.

As a result of the hormone resistance, a meal high in saturated fat can crank up our appetite well after dessert. "Taking time off from a healthy diet to eat most fast foods may have consequences that last for some days, even after one resumes the healthy diet," says University of Cincinnati behavioral neuroscientist Stephen Benoit, who led the study. He believes the findings are likely to apply to humans, too.

Sensing leptin and insulin is like keeping an eye on the body's nutrient status, says Gary Schwartz, a neuroscientist at the Albert Einstein College of Medicine in New York City, who was not involved in the research. "If that eye starts to go blind because you keep giving it too much nutrient, then it can't respond. It can't tell you, 'look, don't eat.'" The result can spark a vicious cycle of metabolic problems and weight gain, he remarks.

But if the hormones are supposed to keep our metabolism from spinning out of control, why would saturated fat—the very thing that obese people have too much of—make us insensitive to them?

"There is a basic mystery here," says William Banks of the Saint Louis Veterans Affairs Medical Center. A leptin expert, he has shown that high levels of saturated fat in the bloodstream block the hormone's passage into the brain, further blinding it to those extra pounds below the neck.

One hint at an explanation for these counterintuitive effects comes from the physiology of starvation. When we starve, our body begins to break down its blubber for energy. As a result, the blood gets flooded with fat, just as it does in obesity and overeating. Apparently erring on the side of caution, our brain interprets free fat (no matter its source) as a starvation alert—had it done otherwise in our evolutionary history, we probably wouldn't be around to worry about it. Says Banks: "In the history of evolution, we've been faced with caloric shortages and starvation much more than we've ever been faced with a wealth of calories."

Read more at http://www.scientificamerican.com/article.cfm?id=lard-lesson-why-fat-lubri

Cosmic pattern to UK tree growth

By Matt Walker
Editor, Earth News

The growth of British trees appears to follow a cosmic pattern, with trees growing faster when high levels of cosmic radiation arrive from space.

Researchers made the discovery studying how growth rings of spruce trees have varied over the past half a century.

As yet, they cannot explain the pattern, but variation in cosmic rays impacted tree growth more than changes in temperature or precipitation.

The study is published in the scientific journal New Phytologist.
"We were originally interested in a different topic, the climatological factors influencing forest growth," says Ms Sigrid Dengel a postgraduate researcher at the Institute of Atmospheric and Environmental Science at the University of Edinburgh.

More on this at http://news.bbc.co.uk/earth/hi/earth_news/newsid_8311000/8311373.stm

Biofuels 'worse than petrol' for climate

Gerard Wynn and Timothy Gardner
Reuters

A new generation of biofuels, meant to be a low-carbon alternative, will on average emit more carbon dioxide over the next few decades than burning petrol, according to a new study.

Governments and companies are pouring billions of research dollars into advanced fuels made from wood and grass, meant to cut carbon emissions compared with petrol.

But according to the study appearing in today's edition of Science, advanced 'cellulosic' biofuels will actually lead to higher carbon emissions than petrol per unit of energy, averaged over the 2000-2030 time period.

That is because the land required to plant fast-growing poplar trees and tropical grasses will displace food crops, and so drive deforestation to create more farmland, a powerful source of carbon emissions.

Biofuel crops also require nitrogen fertilisers, a source of two greenhouse gases: carbon dioxide (CO2) and the more powerful nitrous oxide.

"In the near-term, irrespective of how you go about the cellulosic biofuels program, you're going to have greenhouse gas emissions exacerbating the climate change problem," says lead author Dr Jerry Melillo of the US Marine Biological Laboratory.

Read more at http://www.abc.net.au/science/articles/2009/10/23/2722259.htm

Mouse

No Not the mouse used with a computer. This is the real mouse known as the house which eats anything to everything. They are mainly active at night and live mainly on the ground. Mouses are good climbers as well as swimmers. It relies on its senses of smell and hearing rather than sight to find its way around. It uses nose to track down food and to follow scent paths.

A pair of mice can give birth to 30 or 40 babies a year, even more if food is plentiful.

Many people consider mice to be pests because they destroy food supplies and every carry disease. Mice have played a role in spreading typhus, spotted fever, salmonella, and the bubonic plague. Also they have been used in scientific experiments.

Gecko

The small lizards known as geckos are fun to watch as they move about. Geckos are great climbers because their feet stick to many surfaces. Each of its long, flat toes has thousands of tiny hairs. At the end of each tiny hair are hundreds of even smaller hairs. These hairs fan out to create a strong sticking power that lets the gecko move along areas where many other animals would slip. Geckos usually come out at night and feed on insects.

Some people keep geckos as pets. One of the most popular is the large tokay gecko, which is gray with red and whitish spots and bands. It is possible that a gecko may live 20 or more years when kept by people.

Marsupial

Kangaroos, koalas, and opossums—these unique animals are all marsupials. Marsupials are known for carrying their young in a special pouch. The name marsupial comes from the Latin word marsupium, which means “pouch.”

The largest living marsupials are the red and gray kangaroos of Australia.Some marsupials are carnivores, or meat eaters. For example, the Tasmanian devil feeds on birds, small mammals, and dead animals.

Bears

Bears are found in North America, Europe, and Asia. One species lives in South America. However, there are no bears in tropical Africa.

The polar bear lives mostly in the Arctic north, where its white fur blends in with snow and ice. Polar bears are often seen on drifting masses of floating sea ice called floes. Brown bears, once widespread in Europe and Asia, are now rare. The grizzly bear, a brown bear of northern and western North America, has been killed off in many areas. The Kodiak bear, an Alaskan island bear closely related to the grizzly, is the world's largest living flesh-eating land mammal.

The American black bear is smaller than the brown bears. It still ranges widely in the forests of the United States and Canada. There is also an Asian, or Himalayan black bear. Most bears live in cold or temperate climates, but the sloth bear is a creature of the tropics. It lives in India and Sri Lanka. The sun bear, or Malayan sun bear, lives in the forests of Southeast Asia. The spectacled bear, which gets its name from the light-colored rings around its eyes, is the only bear of the Southern Hemisphere. It is found in the Andes Mountains of Chile, Bolivia, Ecuador, and Peru.

Bears are solitary creatures that avoid each other except in the mating season. Female bears give birth to one to four cubs at a time, usually in winter. Newborn cubs are small, hairless, and helpless creatures unable to open their eyes for about a week. Cubs drink their mother's milk for about two months and stay with her until the next breeding period begins, which is usually about a year and a half after their birth. Bears begin to breed at 2 to 6 years of age. The male bear plays no role in raising the cubs. Most bears live from 15 to 30 years in the wild. Captive bears have lived much longer.

Aardvark

The unusual mammal called the aardvark was named by South Africans in the early 19th century. In the local language, Afrikaans, “aardvark” means “earth pig.” This name aptly describes a large, heavily built animal with thin hair and short, stumpy legs. The aardvark can reach a length of 6 feet (1.8 meters). Its head has huge donkeylike ears, a long snout, and drooping eyelids with long lashes.

Aardvarks, which are also called ant bears, live in dry places in Africa south of the Sahara Desert. During the day they sleep in underground burrows. At night they dig underground for their favorite food, termites. Aardvarks use their sensitive snouts to detect these insects. They break open the termites' nests with their massive, flattened claws and suck up the insects with their long tongues. Although they are not aggressive animals, aardvarks can defend themselves by lashing out with their claws. They can also dig very quickly to bury themselves.

Female aardvarks give birth to one baby per year. After a few weeks the baby begins to follow its mother around. It feeds and travels with her for about six months until it becomes more independent.