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beetles. http://louisfjfsheehan.blogspot.com Worms collected and buried more than 90 percent of ragweed seeds from the surface of the soil around their burrows, the team reports. “The burrow is an environment that the worm is actively maintaining — that’s its universe,” comments soil and ecosystem ecologist Patrick Bohlen, director of the MacArthur Agro-ecology Research Center in Lake Placid, Fla. “Maybe it’s sweeping its front porch. We don’t really know. There isn’t a lot of evidence that they are eating the seeds, but clearly it’s creating an architecture.” “You might think of earthworms just burrowing around — the intestines of the earth,” he adds. “But the worm is living there 365 days a year.” Experiments by Regnier’s team revealed that the night crawlers buried ragweed seeds as deep as 22 cm. There were six times as many seeds in the worms’ burrows as in the surrounding soil. After one season, there was an average of 127 seeds per burrow. “We were astonished by how quickly the seeds were removed,” Regnier says. Seeds that were too large for the worms to pull underground were dragged to the worm’s midden, the little pile of debris that marks the burrow’s front door. Researchers aren’t sure what these middens are for. They are usually made of worm castings, shreds of leaves and grass, but the worms will also add nonedibles, such as stones or old shards of tile. The work enhances our understanding of plant-animal interactions, Regnier says. “We think of ants and mice and squirrels as being very important in dispersing seeds,” she says. “Here’s a new mechanism — they are burying them quite deliberately.” On their own nonnative worms probably spread only 10 meters a year, but they move faster with human help.Leftover fishing bait should be thrown in the trash, Hale says, not dumped in the dirt. It’s likely that the worms will keep moving west — not in a car with Lowly Worm — but with humans, the same way they arrived. For the Arctic, green is the new black. People frequently say “green” to mean “environmentally friendly.” But encroaching conifer forests — really big greens — threaten to further spike the far North’s already low-grade fever. Temperatures in the high Arctic already are climbing “at about twice the global average,” notes F. Stuart Chapin of the University of Alaska Fairbanks. http://louiscjcsheehan.blogspot.com The newest data on the advance of northern, or boreal, forests come from the eastern slopes of Siberia’s northern Ural Mountains. Here, north of the Arctic Circle, relatively flat mats of compressed, frozen plant matter — tundra — are the norm. This ecosystem hosts a cover of reflective snow most of the year, a feature that helps maintain the region’s chilly temperatures. Throughout the past century, however, leading edges of conifer forests began creeping some 20 to 60 meters up the mountains, and in some places these forests are now overrunning tundra, scientists report in the July Global Change Biology. Conifers here now reside where no living tree has grown in some 1,000 years, points out one of the authors, ecologist Frank Hagedorn of the Swiss Federal Institute for Forest, Snow and Landscape Research in Birmensdorf. access Satellite data map a greening Arctic tundra. Brown shows where photosynthesis decreased between 1981 and 2005, and green where it increased. This change resulted mainly from shrubs invading permafrost, beginning a chain of events that may affect global climate.Bunn, EOS Ecologists and climatologists are concerned because emerging forest data suggest that the albedo, or reflectivity, of large regions across the Arctic will change. Most sunlight hitting snow and ice bounces back into space instead of being absorbed and converted to heat. So if a white landscape becomes open sea or boreal forest, what was once a solar reflector becomes a heat collector. Sea-surface ice already is melting in the Arctic, and polar ice sheets are thinning. Warming threatens to further degrade these solar reflectors. So does the advance of boreal forests, Chapin says. “Effects of vegetative changes will be felt first and most strongly locally — in the Arctic,” he says. However, he adds, if the Arctic’s albedo drops broadly, this could aggravate warming underway elsewhere across the planet. Posturing Tree rings from the Arctic Urals show that since the 15th century, many Siberian larch (Larix sibirica Ledeb.) — the primary tree species — have grown in a stunted, shrubby form, sporting multiple spindly trunks. This adaptation to harsh conditions helps the trees weather wind and snow. But the trees invest so many calories in making multistemmed clusters, Hagedorn says, that they end up puny and unable to make seeds. This infertility has thwarted the stand’s spread. access INVADING LARCHESThe upper photo, taken in 1962, shows mostly low vegetation and shrubs on a slope in the Siberian Urals. The lower photo of the same site in 2004 reveals larches building a true forest.Andreas Rigling After about 1900, these larches began to switch from their creeping, multistemmed form to tall trees with a more upright posture, though sometimes with up to 20 stems, Hagedorn and his Russian and Swiss collaborators report. Over time, new trees emerged with a single, upright trunk, at the same time bulking up with more biomass than shrubby, same-age kin. http://louishjhsheehan.blogspot.com Overall, 70 percent of upright larches have emerged in just the past 80 years. Since 1950, 90 percent of local upright larches have been single-stemmed. This forest advance into former tundra coincided with a nearly 1 degree Celsius increase in summer temperature and a doubling of winter precipitation. “That’s a good cocktail for growth,” says arctic plant ecologist Serge Payette of Laval University in Quebec. Whether a tree grows up versus out depends on survival of its uppermost, or apical, buds. Good snow cover will protect those buds from winter damage, he says. Only if they are destroyed will the surviving lateral buds push growth horizontally, he explains. Spruce are North America’s more common boreal species at polar tree lines, Payette says. Some of these also assume a shrubby form, creating what he calls “pygmy forests” perhaps a meter high. But he has witnessed some of these trees assuming new, upright postures as areas warm and get wetter. This process can create the “mirage” of tree line advance, he says. In fact, the trees may not move at all; in-place populations may simply recover from chronic stress and resume growth until they reach their normal height and mass. access HARDY UPSTARTSAlthough some newly invading Ural larches sport multiple, upright trunks, as seen below, others are beginning to grow with a single trunk. The latter have greater vigor and are more fertile.Global Change Biology 2008 Ecologist Andrea Lloyd of Middlebury College in Vermont has been studying the health of boreal tree lines throughout the warming Arctic. As in the Urals, warmth seemed to spur American spruce to move into new terrain. “I’ve also seen spruce advancing upwards,” climbing up mountains to form dense stands, she says. But that’s only part of the story, she finds. Even where stands are advancing, “if you look at individual trees, some are starting to decline.” They’re growing increasingly slowly. Sometimes, as growth slows, tree numbers within a stand may be increasing. “It’s a paradox,” she acknowledges. Forest ecologist Glenn Juday of Alaska-Fairbanks and his student Martin Wilmking have recorded similarly perplexing data from tree rings in 2,600 trees along two mountain ranges in polar Alaska. As the environment warmed, 42 percent of the trees grew more slowly and 38 grew more quickly. Too little water seems a bigger factor affecting tree growth than temperature, although warming can foster drought, Juday acknowledges. Indeed, as the Arctic warms, it will likely become drier, he says. “So we can expect that at least in the western North American Arctic, there are going to be sites that eventually will get too dry to grow trees.” But their loss isn’t likely to compensate for the tundra lost to trees, at least in Arctic-warming potential. In fact, their loss could further perturb the global climate because boreal forests currently hold huge amounts of carbon that had been emitted as carbon dioxide, a greenhouse gas. Until they decompose, they darken the land and remain solar collectors. http://louisbjbsheehan.blogspot.com Once they rot, their carbon will enrich already high atmospheric CO2 levels. Shrubs and microbes The threat of tundra displacement by trees has largely escaped notice, Juday says. And indeed, boreal forest advances in Alaska have been modest, at best. One reason: Seeds don’t normally travel far in the Arctic, and even when they land on tundra, its dense mats resist implantation. Except when those mats have been disturbed. A dry summer and warm September last year allowed a fire to ignite 100,000 hectares (about 250,000 acres) of Alaskan tundra. The huge footprint of disturbed land is now ripe for growing seeds. Fortunately, Juday says, boreal forests are on the other side of a mountain range from this scarred landscape. Throughout the past half-century, a far more pervasive disturbance — what ecologists have taken to calling shrubbification — has been subtly transforming the tundra landscape. It starts with the arrival of tiny shrubs, such as spreading willows perhaps only 7.5 centimeters (about 3 inches) high, explains ecologist Ken Tape, also at Alaska-Fairbanks. He compared repeat photographs of Arctic tundra scapes taken around 1950 and again a few years back. His calculations indicated that for the sites he studied, “there’s been something like a 39 percent increase in shrub cover.” It’s consistent with data from satellite monitoring of Alaska’s high Arctic that have shown “increases in biomass of a similar magnitude — about 25 to 30 percent,” he says. As these willows and other shrubs start moving in, they trap snow, which begins to insulate — and warm — the soil at their feet, explains Andy Bunn, an environmental scientist at Western Washington University in Bellingham. The warming will rouse sleeping bacteria in the soil, which will then begin to feed. In the process, they’ll begin to spew much of the carbon that had been locked up in the formerly frozen soil. This fertilizes the shrubs, fostering the whole warming-growth cycle. “There’s what people call a big Arctic carbon bomb” waiting to go off, Bunn says. Up to 200 petagrams — that’s 200 trillion kilograms — are stored in the top meter of Arctic tundra. For comparison, the atmosphere already has 730 petagrams of carbon in it, he adds. http://louisbjbsheehan.blogspot.com If shrub-related warming releases much of this carbon, it could undermine much of the carbon-limiting measures people are contemplating to slow global warming, he notes. Although trees soak up carbon, boreal trees grow so slowly they’ll likely never keep up with what the soil warming will spew, Bunn says. But forests could exacerbate the problem by darkening the still fairly light-colored shrubby landscape. Warming has so changed the climate of a huge and growing span of tundra that it now hosts a temperature and moisture level that would support forests, Juday notes. “Today, if you planted a tree — in some cases very far up from the current tree line — it would survive in many parts of the tundra.” Just 40 years ago, he says, it wouldn’t. </p> 4417997 2008-07-08 02:02:18 2008-07-08 02:02:18 open open slowly-4417997 publish 0 0 post 0 small-dog http://Louis9J9Sheehan9esquire.blog.ca/2008/07/07/small-dog-4414517/ Mon, 07 Jul 2008 10:41:40 +0200 Beforethebigbang <p>Chihuahuas, Boston terriers, and Pomeranians have this much in common: They’re tiny. Part of what makes them that way is the mutation of a single gene called insulin-like growth factor 1 (IGF1), according to a group of researchers from the University of Utah, Cornell University, and the National Human Genome Research Institute. The researchers began their study by looking at dogs of one breed, the Portuguese water dog, and found that those with one type of mutation of IGF1 were 15 to 20 percent smaller. The researchers ultimately studied 3,000 dogs from 143 different breeds to determine how that gene mutation was distributed across the species. They discovered that the smallest breeds, like Chihuahuas, all had the same gene variant that would make them small. Similarly, 100 percent of the largest dogs, like Great Danes, had a variant that would make them big. The group was surprised that so many small-dog breeds shared the same mutation. “It didn’t need to be that a gene that determines size within breeds would determine size across breeds, but that is how it turned out,” says Carlos Bustamante, an assistant professor of biological statistics and computational biology at Cornell, who crunched the numbers for the project. “Below a few kilograms, it’s staggering. More than 85 percent had the gene variant, about as ‘smoking gun’ of a correlation as we’ve seen.” http://louis2j2sheehan.blogspot.com Domestic dogs are descended from gray wolves, which have only the big version of the IGF1 gene. Bustamante imagines that the small ­mutation probably arose around the start of ­domestication. http://louis2j2sheehan.blogspot.com “You had junky dogs living on the outside of ­settlements,” he says, “so a small mutation might be advantageous—you could get closer to a village without scaring everyone.” The researchers believe the mutation became fixed within different breeds during 300-odd years of artificial selection—that is, dog breeding. However it arose, the switch is not limited to the Canidae family. Mice who’ve had that section of their genes knocked out wind up 40 percent smaller. And, scientists say, humans who share 90 percent of the amino acids found in small-dog IGF1 tend to be the more diminutive specimens of our species. </p> 4414517 2008-07-07 10:41:40 2008-07-07 10:41:40 open open small-dog-4414517 publish 0 0 post 0 http://louis2j2sheehan.blogspot.com team http://Louis9J9Sheehan9esquire.blog.ca/2008/07/07/team-4414495/ Mon, 07 Jul 2008 10:37:12 +0200 Beforethebigbang <p>In September, a team of surgeons and immunologists at Duke University proposed a reason for the appendix, declaring it a “safe house” for beneficial bacteria. Attached like a little wiggly worm at the beginning of the large intestine, the 2- to 4-inch-long blind-ended tube seems to have no effect on digestion, so biologists have long been stumped about its purpose. http://louis8j8sheehan8.blogspot.com That is, until biochemist and immunologist William Parker became interested in biofilms, closely bound communities of bacteria. In the gut, biofilms aid digestion, make vital nutrients, and crowd out harmful invaders. Upon investigation, Parker and his colleagues found that in humans, the greatest concentration of biofilms was in the appendix; in rats and baboons, biofilms are concentrated in the cecum, a pouch that sits at the same location. http://louis8j8sheehan8.blogspot.com The shape of the appendix is perfectly suited as a sanctuary for bacteria: Its narrow opening prevents an influx of the intestinal contents, and it’s situated inaccessibly outside the main flow of the fecal stream. Parker suspects that it acts as a reservoir of healthy, protective bacteria that can replenish the intestine after a bacteria-depleting diarrheal illness like cholera. Where such diseases are rampant, Parker says, “if you don’t have something like the appendix to harbor safe bacteria, you have less of a survival advantage.” </p> 4414495 2008-07-07 10:37:12 2008-07-07 10:37:12 open open team-4414495 publish 0 0 post 0 http://louis8j8sheehan8.blogspot.com angkor http://Louis9J9Sheehan9esquire.blog.ca/2008/07/07/angkor-4414427/ Mon, 07 Jul 2008 10:22:28 +0200 Beforethebigbang <p>The temples of Angkor are architectural marvels and international tourist attractions. But in an August paper in the Proceedings of the National Academy of Sciences, archaeologists from Australia, Cambodia, and France reported using a combination of ground surveys and aerial scans to create a broader, more comprehensive map of the ancient Cambodian ruin, confirming that it was once the center of an incredibly vast city with an elaborate water network. http://louis7j7sheehan.blogspot.com Lead researcher Damian Evans, an archaeologist at the University of Sydney, says the true extent of the city is apparent only from above. Between A.D. 800 and 1500, Angkor’s complex canals, roads, irrigated fields, and dense settlements sprawled across more than 1,160 square miles, almost the size of Rhode Island—and far beyond the area protected within the UNESCO World Heritage Site’s zone today. The city was the preindustrial world’s largest urban complex, made possible by some of the most complicated hydraulic works the world had ever seen. American technology played a critical role in the analysis. NASA’s Jet Propulsion Laboratory flew a 747 specially equipped with ground-scanning radar over the site, teasing out subtle differences in elevation and soil content. Added to conventional aerial photography and confirmed through ground surveys, the radar images showed that Angkor was unsustainable. Stripping off the area’s natural forest cover exposed the complex irrigation systems to unexpected erosion and flooding. “They very intensively reengineered the landscape wherever they went,” Evans says. “When you start creating these incredibly elaborate engineering works, it’s inevitable that you create problems. Angkor engineered itself out of existence.” </p> 4414427 2008-07-07 10:22:28 2008-07-07 10:22:28 open open angkor-4414427 publish 0 0 post 0 http://louis7j7sheehan.blogspot.com clovis http://Louis9J9Sheehan9esquire.blog.ca/2008/07/07/clovis-4414131/ Mon, 07 Jul 2008 09:10:25 +0200 Beforethebigbang <p>Some 13,000 years ago, the Clovis people wandered North America, hunting ground sloths, mammoths, and other creatures—until hunters and prey both vanished. What happened? A team of scientists now think they know: A miles-wide comet, they announced in May, seems to have exploded just north of the Great Lakes, triggering a 1,000-year cold spell that helped bring on the extinction of the Clovis and the animals. http://ljsheehan.blogspot.com For years, the disappearance of the Clovis culture and sudden extinction of 35 genera of animals were explained by two competing theories. One blamed climate change, although similar change at other times had not resulted in mass extinction. http://ljsheehan.blogspot.com The other fingered the humans themselves: Newly arrived from Asia, the Clovis killed off everything in a murderous spree and subsequently starved. “They would be very strange hunters, if you look at the ethnographic record, to knock out 35 genera that quickly,” says Douglas Kennett, an archaeologist at the University of Oregon who conducted the research with 25 colleagues. The key to the new hypothesis is a thin layer of black soil found at more than 50 North American sites. In it are magnetic grains containing iridium, an element thought to indicate extraterrestrial origins. The sediments also contain metallic and carbon spherules, as well as melted charcoal, likely the result of forest fires that swept the continent after the impact. Although no crater has been found, concentrations of these indicators are highest around the Great Lakes. Perhaps the impact was absorbed and erased by the Laurentide Ice Sheet, which at the time reached from the Arctic Ocean to that point, the researchers say. Or maybe the comet exploded before it hit Earth. “Think about it—people would have seen it coming,” says Kennett. “This was a bad day.” </p> 4414131 2008-07-07 09:10:25 2008-07-07 09:10:25 open open clovis-4414131 publish 0 0 post 0 http://ljsheehan.blogspot.com battery http://Louis9J9Sheehan9esquire.blog.ca/2008/07/07/battery-4413740/ Mon, 07 Jul 2008 07:31:11 +0200 Beforethebigbang <p>Imagine a battery as flexible as paper—because it is made of paper. In August, a team at Rensselaer Polytechnic Institute in New York unveiled a small sheet of black paper that can store and discharge electricity.http://louis1j1sheehan1.blogspot.com In addition to being light and flexible, it can extract electrical energy from human blood and sweat, making the device potentially usable as a power source for tiny medical devices inside the human body. The RPI team made the paper battery by first growing an array of carbon nanotubes on a silicon surface and then covering the array in dissolved cellulose (the main constituent of paper). The cellulose forms a flexible sheet studded with embedded nanotubes that can be peeled away from the substrate. The nanotubes make the sheet as black as coal, but only a small quantity is needed. “Ninety percent of the device is still normal paper you buy at the store,” says Pulickel Ajayan, one of the lead researchers and a materials scientist. “The best part about this is its versatility,” he continues. “It’s paper. http://louis1j1sheehan1.blogspot.comWe can wrap a device in paper that also works as the device’s power source. Or we can slide it into a tiny crevice—anywhere, really. It is vastly superior to a conventional battery. If you cut a normal battery in half, you break it; it’s useless. If you cut a paper battery in half, you just make two batteries that have half the power of the original.” Want more power? Stack sheets of the paper together. “It’s not just a paper battery; it’s the ultimate battery,” Ajayan says. </p> 4413740 2008-07-07 07:31:11 2008-07-07 07:31:11 open open battery-4413740 publish 0 0 post 0 http://louis1j1sheehan1.blogspot.com &lt;a href=&quot;http://technorati.com/claim/q7962njvsb&quot; rel=&quot;me&quot;&gt;Technorati Profile&lt;/a&gt; http://Louis9J9Sheehan9esquire.blog.ca/2008/07/07/alt-a-href-aquot-http-technorati-com-cla-4413608/ Mon, 07 Jul 2008 06:58:07 +0200 Beforethebigbang <a href="http://technorati.com/claim/q7962njvsb" rel="me">Technorati Profile</a> 4413608 2008-07-07 06:58:07 2008-07-07 06:58:07 open open alt-a-href-aquot-http-technorati-com-cla-4413608 publish 0 0 post 0 ddt http://Louis9J9Sheehan9esquire.blog.ca/2008/07/07/ddt-4413596/ Mon, 07 Jul 2008 06:54:42 +0200 Beforethebigbang <p>Birth control pills work wonders in preventing human reproduction. Unfortunately, they’re also effective on an unintended target—fish. In fact, the synthetic estrogen in contraceptives can wipe out entire fish populations, according to Karen Kidd of the Canadian Rivers Institute at the University of New Brunswick. Her findings, reported in the Proceedings of the National Academy of Sciences in May, suggest that tougher sewage treatment could safeguard the little swimmers. http://louis9j9sheehan9esquire.blogspot.com Previous studies linked wild male fish possessing uniquely female characteristics—production of eggs and the egg protein vitellogenin (VTG)—to the presence of natural and synthetic estrogens in waterways downstream of sewage outfalls; one estrogen source is the hormone that women excrete in their urine. http://louis9j9sheehan9esquire.blogspot.com For three years, Kidd and company added the same synthetic estrogen as in the pill to a research lake operated by Fisheries and Oceans Canada to mimic the chronic low levels released by treatment facilities. During the study, all the lake’s male fathead minnows began producing eggs and VTG, the female fish’s egg development became delayed, newly hatched fish disappeared, and by the end, minnows were all but locally extinct. Kidd says the short-lived minnows were the first to go, but larger fish, many of which feed on minnows, would most likely have been affected over time. While more advanced secondary and tertiary sewage treatments, including measures like activated charcoal filtration, can remove 90 to 100 percent of the estrogen in wastewater, some North American cities employ only primary treatment. “A lot of our regulations focus on persistent chemicals like DDT,” Kidd says. “We need to pay more attention to nonpersistent ones in wastewater because fish are being continuously exposed, and even at low levels, that can have serious consequences.”</p> 4413596 2008-07-07 06:54:42 2008-07-07 06:54:42 open open ddt-4413596 publish 0 0 post 0 http://louis9j9sheehan9esquire.blogspot.com