tinyurl.com/5hfhj5 -> environment.newscientist.com/article/dn14593-wind-turbines-make-bat-lungs-explode.html
Advertising "Beware: exploding lungs" is not a sign one would expect to see at a wind farm. But a new study suggests this is the main reason bats die in large numbers around wind turbines. The risk that wind turbines pose to birds is well known and has dogged debates over wind energy. In fact, several studies have suggested the risk to bats is greater.
Why bats - who echolocate moving objects - are killed by turbines has remained a mystery until now. The research council thought the high-frequency noise from the turbines' gears and blades could be disrupting the bats' echolocation systems. In fact, a new study shows that the moving blades cause a drop in pressure that makes the delicate lungs of bats suddenly expand, bursting the tissue's blood vessels. This is known as a barotrauma, and is well-known to scuba divers. "While searching for bat carcasses under wind turbines, we noticed that many of the carcasses had no external injuries or no visible cause of death," says Erin Baerwald of the University of Calgary in Canada. Internal injuries Baerwald and colleagues collected 188 dead bats from wind farms across southern Alberta, and determined their cause of death. They found that 90% of the bats had signs of internal haemorrhaging, but only half showed any signs of direct contact with the windmill blades. Only 8% had signs of external injuries but no internal injuries. The movement of wind-turbine blades creates a vortex of lower air pressure around the blade tips similar to the vortex at the tip of aeroplane wings. Others have suggested that this could be lethal to bats, but until now no-one had carried out necropsies to verify the theory. Baerwald and her colleagues believe that birds do not suffer the same fate as bats - the majority of birds are killed by direct contact with the blades - because their lungs are more rigid than those of bats and therefore more resistant to sudden changes in pressure. Bats eat nocturnal insects including agricultural pests, so if wind turbines affected their population levels, this could affect the rest of the local ecosystems. "If bats are killed in Canada that could have consequences for ecosystems as far away as Mexico." Windy day One solution could be to increase the minimum wind speed needed to set the blades in motion. The study was funded by a number of bat conservation groups together with energy companies with a financial interest in wind energy, such as Shell Canada and Alberta Wind Energy.
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VIEW THREAD >> building properies on mining claims By Carl Rice Fri Aug 17 18:06:11 BST 2007 Building properties as an option to mining is not allowed on federal mining claims. The current moratorium on patent proceedings insures this. Your statement concerning this is in error or puposely deceptive to garner support to stop all mining.
VIEW THREAD >> Anti-mining agenda By G Morita Fri Aug 17 18:40:51 BST 2007 The EWG and others of their ilk would have us ban all mining within the US. This would have the effect of exporting the environmental damage caused by mining to the Third World where the environmental laws are weaker or non-existent. Another side effect of this prevalent attitude is to make the US dependent on foreign sources ofthe raw materials needed in today's high tech economy. This NIMBY attitude simply shows how narrow minded these people can be. It is better to keep the mining of mineral resources at home where the environmental laws strong rather than export the impact on another country that is ill equipped to manage mining properly.
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