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_________________________________________________________________ Tuesday, January 12, 1999 Rising mercury hurts loons Tailpipe of North America receives `warning' By David Swick THE CRY OF LOONS, a new report by two Acadia University biologists suggests, might be a cry for help. Graduate student Joe Nocera and professor Dr. Phil Taylor say loon chicks in Kejimkujik National Park and southern New Brunswick are demonstrating unusual behaviour. It's a sign, they believe, mercury poisoning is impairing the loons' nerve functioning. "This is a warning," Nocera says. "It's not loon armageddon - yet. A lot depends on where the mercury is coming from. If it's in natural bedrock and leaching through, that's one thing. If it's coming through the atmosphere then there's lots to do." Excessive preeners Three years ago scientists discovered Keji loons have North America's highest recorded mercury levels. Now, in a report published in Conservation Ecology, Nocera and Taylor say loon chicks in Keji and New Brunswick's Lepreau watershed are engaging in excessive preening, and don't ride on their parents' backs so often. Riding on back protects the chicks from predators; excessive preening wastes valuable energy and so makes the young more vulnerable, too. Chicks with lower levels of mercury, a potent nerve poison, have not changed their behaviour. Coal-fired power plants, incinerators, and other industrial concerns puff mercury into the atmosphere. A recent report in Environmental Toxicology and Chemistry, Nocera said, showed the level of mercury in loon blood increases from west to east across the continent. Toxins are deposited in a similar pattern. Nova Scotia, Nocera said, is the tailpipe of North America. "We get all these atmospheric wind patterns that merge on Nova Scotia. When they cross Fundy they cool down, and precipitate here. That's why we get more precipitation than New Brunswick. "We can't point fingers, but all the evidence is pointing to a manmade source." Scientists studying pollution find loons especially interesting because loons are a top predator in the aquatic food chain, and absorb mercury from eating fish. This winter Nocera is finishing three years of graduate study. His last two summers were spent on the shores of Keji lakes, or lakes in the Lepreau watershed, watching loons from breakfast to sundown. Findings for New Brunswick are discouraging, too, but not as bad as Keji. A Connecticut native, Nocera came to Nova Scotia to work on loon research. The birds had fled Connecticut - and much of New England - before he grew up. He heard his first loon in Maine in the early '90s - and that was one crying from the ocean. He'd never seen a loon on freshwater before coming to Nova Scotia. The bird has three haunting, famous cries: the sad wail; the tremolo, a staccato that crescendos and then drops; and the yodel (made only by males). But in total, loons make five calls. "There are also the hoot and the mew," Nocera said, "very soft cat-like calls used only in family units. You have to be really close to hear them." It's all in the air flow Loons cry by contracting muscles to push air through a complicated, multi-chambered windpipe. "We speak by contracting the larynx, which is like a knot, and controlling air flow through one channel. All birds have a syrinx instead of a larynx. It vibrates differently, and has four - a few birds even have eight - caverns inside it. "When they contract muscle, the syrinx vibrates in different patterns." _____________________________________________________________ _____________________________________________________________ References 0. http://www.hfxnews.southam.ca/Perspective/Swick.html -*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*- You received this because you are subscribed to "sust-mar", the Sustainable Maritimes mailing list. To unsubscribe, send email to <majordomo@chebucto.ns.ca> with "unsubscribe sust-mar" (without quotes) as the body of your message. To post a message to sust-mar subscribers, send it to <sust-mar@chebucto.ns.ca> Posts that are off-topic or excessive length (10K) will be rejected. For help contact <sust-mar-owner@chebucto.ns.ca>
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