Invasive Mussel Not Harmed by Toxins, Invades Freshwaters of Europe, North America

           While most freshwater mussels react stressfully and weaken when exposed to the toxins in blue-green algae in their water environment, the little zebra mussel is rather indifferent. It is not affected by the toxins, and this helps it outmatch stressed and weakened mussels, report researchers from the University of Southern Denmark. This is bad for the biodiversity, and in some countries the superior zebra mussels imposes great costs to the industry.

At first glance it looks like good news: Researchers have discovered that the freshwater zebra mussel (Dreissena polymorpha) is not damaged from exposure to toxins from blue-green algae (cyanobacteria) and other toxic substances that could
constitute a problem for freshwater mussels. On the contrary, they seem completely unaffected and thus they manage significantly better in a water environment than other freshwater mussels and this is what worries the scientists: Many places in Europe the zebra mussels have already outmatched other mussel species and in the U.S.
they are so widespread that they pose a threat.

"Zebra mussels live in large colonies in the Great Lakes in the United States,
and they are a huge problem. They need something hard to attach themselves to and often
they find a suitable surface on the inside of the pipes carrying water from the Great
Lakes into factories and other industries along the lake. Often they sit so close
that they block the water intake," explains associate professor Claudia Wiegand,
who studies environmental stress physiology and aquatic toxicology at the Department of Biology, University of Southern Denmark.

Efforts to prevent the zebra mussels from attaching themselves to the pipes and remove those attached have already cost several million dollars.

Safe' Levels of Environmental Pollution May Have Long-Term Health Consequences

This study adds evidences for rethinking the way of addressing risk assessment especially when considering that the human population is widely exposed to low levels of thousands of chemicals, and that the health impact of realistic mixtures of pollutants will have to be tested as well," said Brigitte Le Magueresse-Battistoni, a researcher involved in the work from the French National Institute of Health and Medical Research (INSERM). "Indeed, one pollutant could have a different effect when in mixture with other pollutants. Thus, our study may have strong implications in terms of recommendations for food security. Our data also bring new light to the understanding of the impact of environmental food contaminants in the development of metabolic diseases."

To make this discovery, scientists used two groups of obese mice. Both were fed a high-fat, high-sucrose enriched diet, with one group receiving a cocktail of pollutants added to its diet at a very low dosage. These pollutants were given to the mice throughout -- from pre-conception to adulthood. Although the researchers did not observe toxicity or excess of weight gain in the group having received the cocktail of pollutants, they did see a deterioration of glucose tolerance in females, suggesting a defect in insulin signaling. Study results suggest that the mixture of pollutants reduced estrogen activity in the liver through enhancing an enzyme in charge of estrogen elimination. In contrast to females, glucose tolerance was not impacted in males exposed to the cocktail of pollutants. However, males did show some changes in liver related to cholesterol synthesis and transport. This study fuels the concept that pollutants may contribute to the current prevalence of chronic diseases including metabolic diseases and diabetes.

Americans Diagnosed With Lyme Disease

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The preliminary estimates were presented Sunday night in Boston at the 2013 International Conference on Lyme Borreliosis and Other Tick-Borne Diseases.

This early estimate is based on findings from three ongoing CDC studies that use different methods, but all aim to define the approximate number of people diagnosed with Lyme disease each year. The first project analyzes medical claims information for approximately 22 million insured people annually for six years, the second project is based on a survey of clinical laboratories and the third project analyzes self-reported Lyme disease cases from a survey of the general public.

Each year, more than 30,000 cases of Lyme disease are reported to CDC, making it the most commonly reported tick-borne illness in the United States. The new estimate suggests that the total number of people diagnosed with Lyme disease is roughly 10 times higher than the yearly reported number. This new estimate supports studies published in the 1990s indicating that the true number of cases is between 3- and 12-fold higher than the number of reported cases.

"We know that routine surveillance only gives us part of the picture, and that the true number of illnesses is much greater," said Paul Mead, M.D., M.P.H, chief of epidemiology and surveillance for CDC's Lyme disease program. "This new preliminary estimate confirms that Lyme disease is a tremendous public health problem in the United States, and clearly highlights the urgent need for prevention."

CDC continues to analyze the data in the three studies to refine the estimates and better understand the overall burden of Lyme disease in the United States and will publish finalized estimates when the studies are complete. Efforts are also underway at CDC and by other researchers to identify novel methods to kill ticks and prevent illness in people.

Sea Otters Promote Recovery of Seagrass Beds

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Scientists studying the decline and recovery of seagrass beds in one of California's largest estuaries have found that recolonization of the estuary by sea otters was a crucial factor in the seagrass comeback. Led by researchers at the University of California, Santa Cruz, the study will be published in the Proceedings of the National Academy of Sciences the week of August 26.
 
Seagrass meadows, which provide coastal protection and important habitat for fish, are declining worldwide, partly because of excessive nutrients entering coastal waters in runoff from farms and urban areas. The nutrients spur the growth of algae on seagrass leaves, which then don't get enough sunlight. In Elkhorn Slough, a major estuary on California's central coast, algal blooms caused by high nutrient levels are a recurring problem. Yet the seagrass beds there have been expanding in recent years.

"When we see seagrass beds recovering, especially in a degraded environment like Elkhorn Slough, people want to know why," said Brent Hughes, a Ph.D. candidate in ecology and evolutionary biology at UC Santa Cruz and first author of the PNAS study. His coauthors include Tim Tinker, a wildlife biologist with the U.S. Geological Survey, and Kerstin Wasson, research coordinator for the Elkhorn Slough National Estuarine Research Reserve, who are both adjunct professors of ecology and evolutionary biology at UCSC.

Hughes and his colleagues documented a remarkable chain reaction that began when sea otters started moving back into Elkhorn Slough in 1984. The sea otters don't directly affect the seagrass, but they do eat enormous amounts of crabs, dramatically reducing the number and size of crabs in the slough. With fewer crabs to prey on them, grazing invertebrates like sea slugs become more abundant and larger. Sea slugs feed on the algae growing on the seagrass leaves, keeping the leaves clean and healthy.

Maulings by Bears: What's Behind the Recent Attacks?

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The recent bear attacks in North America over the past week are unrelated to one another and are not indicative of a trend, experts say.

At least six people in five states have been mauled by black and brown bears recently. The latest incident occurred on Saturday, when a hunter in the remote Alaskan wilderness was attacked by an alleged brown bear, also known as a grizzly bear, and survived more than 36 hours before being rescued by the state's air national guard.

Last Thursday, hikers in Yellowstone National Park in Wyoming were attacked by a female grizzly after they got too close to her cubs. One of the men was clawed and bitten on his backside.

Also on Thursday, 12-year-old Abigail Wetherell was attacked by a black bear while out on an evening jog in northern Michigan.

According to news reports, Wetherell initially tried to run away from the bear, but she was chased and knocked down. After trying to escape a second time and failing, she played dead. A neighbor who heard the girl scream eventually scared the animal away, but not before it slashed Wetherell's thigh.

Over the weekend, conservation officers shot and killed a black bear they believed to be the one that attacked Wetherell.

Bear expert John Beecham said it's unclear from the accounts he's read why the animal might have attacked the girl. "It might have been a female [bear] and she had young, or the girl might have just come up on the bear fairly quickly while running through the woods, and it perceived her as a threat and attacked," he said.

Out of Africa? New Bamboo Genera, Mountain Gorillas, and the Origins of China's Bamboos

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African mountain bamboos are something of a mystery, as nearly all bamboos are found in Asia or South America. Hidden away up mountains in the tropics where they provide food for gorillas, just as China's bamboos provide food for the Giant Panda, there are apparently only 2 species, and they had not been examined in very great detail, except by the gorillas, see image.

It had been thought that they were very closely related to the hundreds of similar bamboos in Asia, but their respective ranges are separated by thousands of miles. As flowering in bamboos is such a rare event, spreading by seed takes a very long time, and the suspicion arose that they might be old enough to represent new genera, and possibly could even be remnants of the earliest temperate bamboos, which spread to Asia on drifting tectonic plates. A new study published in the open access journal PhytoKeys, studies the diversity and evolution of African bamboo.

Having studied bamboos in the Himalayas extensively, and edited the descriptions of all the bamboos of China for the Flora of China Project of Academia Sinica and Missouri Botanical Gardens, Dr Chris Stapleton turned his attention to the bamboos of Africa. He found that the features of the mountain bamboos were significantly different to those of Asia, and together with the large geographic separation, the differences were sufficient for the recognition of 2 new African genera, now named Bergbambos and Oldeania, after their local names in the Afrikaans and Maasai languages. The species are now Bergbambos tessellata and Oldeania alpina.

Scientists Analyze the Effects of Ocean Acidification On Marine Species

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Ocean acidification could change the ecosystems of our seas even by the end of this century. Biologists at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), have therefore assessed the extent of this ominous change for the first time. In a new study they compiled and analysed all available data on the reaction of marine animals to ocean acidification. The scientists found that whilst the majority of animal species investigated are affected by ocean acidification, the respective impacts are very specific.

The AWI-researchers present their results as an Advance Online Publication on Sunday 25 August 2013 in Nature Climate Change.

The oceans absorb more than a quarter of anthropogenic carbon dioxide emitted to the atmosphere. They form a natural store without which Earth would now be a good deal warmer. But their storage capacities are limited and the absorption of carbon dioxide is not without consequence. Carbon dioxide dissolves in water, forms carbonic acid and causes the pH value of the oceans to drop -- which affects many sea dwellers. In recent years much research has therefore been conducted on how individual species react to the carbon dioxide enrichment and the acidifying water. So far the overall extent of these changes on marine animals has been largely unknown.

Life in Antarctica Relies on Shrinking Supply of Krill

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On the Antarctic island of South Georgia, in February, toward the middle of what passes for summer at the bottom of the world, I hurried through the ruined whaling station of Grytviken.

I had an appointment at the British Antarctic Survey station on the opposite side of King Edward Cove. I was to interview a marine ecologist working on krill. I did not want to be late.

The keystone of the South Georgia ecosystem, the secret to the miraculous abundance of wildlife on this stark, cold, windswept island—the foundation, indeed, for almost all vertebrate life in the Antarctic—is krill.

South Georgia and the South Sandwich Islands are administered from the Falkland Islands as a British Overseas Territory, in which the little outpost of Grytviken is the only inhabited spot. The inhabitation is very marginal. In southern winter there are just eight staff members of the British Antarctic Survey, including a doctor, a government officer, and a postal clerk. A handful of visiting scientists augment this skeleton crew in southern summer.

Grytviken is gritty and grim. The name means "Pot Bay," a reference to the cauldrons in which the Norwegian whalers here rendered oil from blubber. It is apt. The rusting vats, boilers, ramps, chimneys, and ramshackle buildings of the long-abandoned whaling station; the wrecks of the catcher boats stranded on the waterfront; and the rows of giant whale-oil tanks upslope are all the apparatus of a genocide, in the literal, Latin sense of the word. The genus was Balaenoptera, the baleen whale.

Less Ice Equals More Seal Strandings

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Harp seals mate and rear their young on the sea ice off the east coast of Canada in the spring and move north as the weather warms. But increasing numbers of seals are ending up stranded along the U.S. East Coast, as far south as the Carolinas, far away from where they should be at this time of year.

The Ocean Is In Danger!
A look at the dire state of perhaps the most interesting and diverse part of our planet.
STOCKBYTE/GETTY IMAGES
As ice levels in the North Atlantic have declined, the number of seals that have wound up on beaches, either dead or in poor health, has increased, new research shows.

The study, published this month in the journal PLOS ONE, suggests that the decline of sea ice is at least partially responsible for the increase in seal strandings, said Brianne Soulen, a study co-author and biologist at the University of North Texas. Demographic factors also play a major role: A large portion of stranded seals are young, and the majority (62 percent) are male, said Soulen, who performed the research while a graduate student at Duke University. [Gallery: Seals of the World]

On Earth's Cold Edge: Photos
Males may be more likely to get stranded because they tend to wander farther afield once on their own, Soulen told LiveScience.

The study was able to mostly rule out the possibility that strandings are due to inbreeding, finding that stranded seals are just as genetically diverse as non-stranded seals.

"Genetics didn't seem to have an influence," Soulen said.

The snow-colored harp seals mate and give birth on sea ice, then mothers nurse and stay with their young. After that, the pups are on their own. The researchers hypothesize that in years with less ice, the ice that exists becomes crowded, and some seals are forced into the water before they've learned how to navigate or how and where to fish, Soulen said. This may lead them to follow groups of fish moving south, or allow them to become disoriented, she added.

Baddass Shrew Lifts Logs, Can't Be Stomped

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A new species of hero shrew, recently found in Africa, is now known to be one of the strongest, sturdiest mammals in the animal kingdom.

The shrew, Scutisorex thori, measures less than a foot long and weighs only 1.7 ounces, and yet it can lift heavy logs. The appropriately named new “hero,” found in the Democratic Republic of the Congo and described in the latest Royal Society Biology Letters, can also often survive attempted squishing.

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Thresher Shark And 3-D Printed Duck Feet
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DCI
Lead author William Stanley, of the Field Museum of Natural History, explained to Discovery News that locals used to demonstrate the sturdiness of these tiny mammals to scientists. When researchers first documented the genus back in the early 1900s, locals immediately recognized the furry shrew.

“'Oh, that’s the hero shrew,' they said,” Stanley explained. “'We use it as a talisman. It renders us invincible to bullets and spears.'”

“At that point,” Stanley continued, “one of the men stood on the tiny mammal for 5 minutes. The shrew walked away unscathed.”

The new shrew, which sports thick, dark hair, appears to be just as strong.

Stanley and his team collected some of the mammals near the village of Baleko in the Congo. Detailed analysis of their body structure revealed that they are similar, yet distinctly different, from the other known hero shrew, Scutisorex somereni.

The most noteworthy feature that the shrews share in common is their unique spine.

“It’s massively reinforced, resulting in tremendous strength,” Stanley said.

Climate Change 10,000 Times Faster Than Evolution

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Evolution can be fast, but not fast enough to keep up with the rate of human-caused climate change, say two researchers who have studied the evolution rates of hundreds of species in the past.

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DCI
In fact, many vertebrate species would have to speed up their evolution rate 10,000 times to match today's pedal-to-the-metal rate of global warming, according to John Wiens, an ecology and evolutionary biology professor at the University of Arizona, and Ignacio Quintero, a postgraduate research assistant at Yale University.

"A big question is 'Can some species adapt quickly enough to survive?'" said Wiens. “So we looked at 17 groups of animals” comprising 540 species that included amphibians, birds, reptile and mammals, to see how they adapted to temperature changes in the past. “We estimated the rate of climate change for these species.”

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Specifically, they looked at when these species split into new species based on genetic data, which is a measure of their rate of evolution, and compared that to climate changes in the niches where those animals lived at those same times in geological history. What they found was that the species could handle a global temperature change of about one degree centigrade per million years. Their results appear in a paper in the latest issue of the journal Ecology Letters.

The problem, of course, is that humans are un-sequestering and burning millions of years worth of carbon-rich fossil fuels and releasing their heat-retaining gases into the atmosphere at a rate that's causing a temperature rise of perhaps 4 degrees Celsius by the year 2100. So if a species can't move to a nearby cooler habitat, it will be unlikely to evolve out of its predicament and survive.

All this seems to fly in the face of a variety of special cases of rapid evolution that have been documented in birds, reptiles and amphibians. But that's not quite so, explained evolutionary biologist Robert Holt of the University of Florida.

The rate of evolution of a particular group of animals probably has a lot to do with how big a set of genetic tools, or flexibility to develop new traits, a species has to work with. Some species have more than others, Holt said.

Crickets Act Differently When Others Are Watching

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Everybody loves an audience—even crickets.

A new study shows that the insects change their aggressive behavior when they know other crickets are watching, the first time this phenomenon has been observed in any invertebrate. Mammals, birds, and fish are all known to be influenced by others.

In recent experiments, male crickets fighting in an arena acted more violently—and upon winning, were more jubilant—when other male or female crickets were in the audience. (See National Geographic's bug videos.)

Found worldwide, crickets live in communities defined by conflicts between individuals, usually to gain access to territories, resources, and mates.

But most previous research has focused on the fighters themselves, without placing them in the social networks in which they live.
Now, the new study reveals that cricket behavior "is much more complex than we give them credit for," said study leader Lauren Fitzsimmons, a biologist at the University of Windsor in Ontario, Canada.

Robert Matthews, a professor emeritus of entomology at the University of Georgia who was not involved in the study, said, "It's an area that should have been looked at long ago.

"Contests don't occur in isolation," he said. "They always are in a social context."
Taking the Stage

For their experiments, Fitzsimmons and colleagues caught male and female crickets from local fields and reared their offspring in isolation in the laboratory. The team then put pairs of either wild-caught males or laboratory-raised males in a small arena at separate times, which always led to fights.

In a glass-separated viewing area adjacent to the arena, the scientists set up experiments with three audience situations: a male watching a fight, a female watching a fight, or no audience. The lab-raised male fighters had a lab-raised audience, and the wild crickets had a wild-caught audience. (See pictures of the world's deadliest animal battles.)

The researchers then videotaped each fight and played them back in slow motion, noting the aggression and overall behavior of the males in the three separate audience situations.

Mr. Badger Should Be Worried: Britain Ponders a Cull

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Britain's Parliament held a four-hour debate in the House of Commons this past Wednesday, and it wasn't about public spending cuts, the war in Afghanistan, or abortion rights.

It was about badgers.
A badger, for those not acquainted with the species, is a mammal about three feet long with gray fur, a mouthful of sharp teeth, and a black-and-white face striped like a zebra crossing. Meles meles, the European badger, is indigenous to the United Kingdom, lives in an underground labyrinth of tunnels called a sett, and feeds on worms and grubs. There are about 300,000 badgers in England.


The badger has been around long enough to have survived two Ice Ages, but if the Conservative-dominated coalition government executes its plan, some 5,000 will not survive two government-led trials that are the prelude to a culling policy that aims to reduce the spread of tuberculosis (known to be carried by badgers) in cattle.


In 1971, a dead badger was found in a barn in Gloucester, autopsied, and found to be infected with TB. The concern—that badgers transmit the bacterium to cows, thereby putting a farm at risk of being shut down until the infection has cleared—has enmeshed scientists, politicians, government bureaucrats, and farmers ever since.


Opposition Gathers Steam

Last year, the Department for Environment, Food and Rural Affairs (DEFRA) announced its intention to test the "safety, humaneness, and efficacy" of culling by targeting 5,000 badgers in Gloucestershire and Somerset—two infection hotspots.


As the proposed cull drew closer, the controversy widened to include celebrities like Queen guitarist Brian May, who led a protest march in London last Saturday and recorded a song called "Badger Swagger"; the rock star Meatloaf; and actress Dame Judi Dench, who posted a video on YouTube calling for a stop to culling.


An anti-culling petition has 235,000 signers, and there's an online threat of a voodoo curse on Environmental Secretary Owen Patterson, a hard-line advocate of the cull. Others have weighed in with tweets, blogs, and letters to the editors of British newspapers. "Cull the politicians instead," one reader wrote the Daily Mail. On the other side, a farmer's wife pointed out that "we wouldn't be having any of this nonsense if this was about culling rats."

How Diving Mammals Stay Underwater for So Long

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Imagine holding your breath while chasing down a giant squid (Architeuthis dux)—multi-tentacled monsters wielding suckers lined with tiny teeth—in freezing cold water, all in the dark. That would take a lot out of anybody, yet sperm whales (Physeter macrocephalus) do this day in and day out.

The ability to dive underwater for extended periods is a specialized feat marine and aquatic mammals have evolved over millions of years. Diving mammals will slow their heart rate, stop their breathing, and shunt blood flow from their extremities to the brain, heart, and muscles when starting a dive. (Related: "Can Diving Mammals Avoid the Bends?")

But champion divers, such as elephant seals, can hold their breath for about two hours. "It was known that they rely on internal oxygen stores when they're down there," said Michael Berenbrink, a zoologist at the University of Liverpool, England, who specializes in how animals function.

But there was something else going on in the bodies of these animals that researchers were missing, until now.

So what's new? A study published June 13 in the journal Science reports that diving mammals—including whales, seals, otters, and even beavers and muskrats—have positively charged oxygen-binding proteins, called myoglobin, in their muscles.

This positive characteristic allows the animals to pack much more myoglobin into their bodies than other mammals, such as humans—and enables diving mammals to keep a larger store of oxygen on which to draw while underwater.

Why is it important? Packing too many proteins together can be problematic, explained Berenbrink, a study co-author, because they clump when they get too close to each other.

"This [can cause] serious diseases," he added. In humans, ailments like diabetes and Alzheimer's can result.

But myoglobin is ten times more concentrated in the muscles of diving mammals than it is in human muscles, Berenbrink said.

Since like charges repel each other—think of trying to push together the sides of two magnets with the same charge—having positively charged myoglobin keeps the proteins from sticking to each other.

Winners of 2013 Amateur Contest

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Captured by Kyle McBurnie, the photo is the overall winner of the University of Miami's Rosenstiel School of Marine and Atmospheric Science's Underwater Photography Contest, which recognizes amateur photography. (See the best underwater pictures of 2012.)

Started in 2005, the contest has grown in popularity, with over 700 entries submitted this year, according to university scientist and contest judge Jiangang Luo.

"All the pictures we got were large, and high quality," said Luo. "It was a really tough job to narrow it down to a few."

The contest is open to any photography enthusiast, as long as they earn less than 20 percent of their income taking pictures. This year, entries came from all over the globe, with submissions from 23 countries. Categories include macro, wide angle, fish or marine animal portrait, and student work. (Get National Geographic's underwater-photography tips.)

Luo said that he and his fellow judges—photographer and university lecturer Myron Wang and underwater photographer Nicole Wang—unanimously agreed on the seal photo because it stood out from the others.

"The organizers would flash the photos in front of us," he explained, "and when that one showed up it caught all of our attentions."

Sea Lampreys Have Hot Sex

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Male sea lampreys need to be pretty hot to attract females — thermally hot, that is.

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DCL Biologists from Michigan State University have discovered a ridge of fat cells near the anterior dorsal fins of sexually mature male lampreys that heats up when females approach. Until now, scientists had thought this "fat bump" was just ornamental.

In addition, this is the first such thermogenic, or heat-producing, tissue identified in a cold-blooded species, the team reported last week in The Journal of Experimental Biology. (See Video of Lampreys' Hot Sex)

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"In bears, when they come out of hibernation, this type of brown fat helps them become active again," said Yu-Wen Chung-Davidson, a biologist at Michigan State University and a co-author of the paper. "This fish also has this fat cell that generates heat. It's beyond my imagination."

Producing heat is energy-intensive and burns a lot of calories, especially in cold-blooded animals. But sea lampreys die once they spawn, so it's in their best interest to use up whatever energy they have to secure a mate, Chung-Davidson told LiveScience.Undo editsAlpha