postMigrator

Rapid Climate Change

By postMigrator November 29, 2007 November 29, 2007 RT Newswire

American Institute of Physics www.aip.org

Physics Today
August 2003, page 30
http://www.aip.org/pt/vol-56/iss-8/p30.html

The Discovery of Rapid Climate Change

Only within the past decade have researchers warmed to the possibility of abrupt shifts in Earth’s climate. Sometimes, it takes a while to see what one is not prepared to look for.

Spencer Weart

How fast can our planet’s climate change? Too slowly for humans to notice, according to the firm belief of most scientists through much of the 20th century. Any shift of weather patterns, even the Dust Bowl droughts that devastated the Great Plains in the 1930s, was seen as a temporary local excursion. To be sure, the entire world climate could change radically: The ice ages proved that. But common sense held that such transformations could only creep in over tens of thousands of years.

In the 1950s, a few scientists found evidence that some of the great climate shifts in the past had taken only a few thousand years. During the 1960s and 1970s, other lines of research made it plausible that the global climate could shift radically within a few hundred years. In the 1980s and 1990s, further studies reduced the scale to the span of a single century. Today, there is evidence that severe change can take less than a decade. A committee of the National Academy of Sciences (NAS) has called this reorientation in the thinking of scientists a veritable “paradigm shift.” The new paradigm of abrupt global climate change, the committee reported in 2002, “has been well established by research over the last decade, but this new thinking is little known and scarcely appreciated in the wider community of natural and social scientists and policymakers.”1

End of excerpts. For the full article,
http://www.aip.org/pt/vol-56/iss-8/p30.html
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Climate, Disease, & Amphibians

By postMigrator November 29, 2007 November 29, 2007 Uncategorized

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“Fueled by warm weather, ‘this infection kills steadily and slowly
over the course of summer,’ Green says.”

” ‘… this wicked-looking organism is very primitive’ and appears
to ‘phylogenetically sit at the spot where animals and fungi diverged.’ ”
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Science News Online
Week of Nov. 24, 2007; Vol. 172, No. 21

Tadpole Slayer: Mystery epidemic imperils frogs
http://www.sciencenews.org/articles/20071124/fob7.asp
Janet Raloff

From Alaska to Florida, a novel and yet-unnamed protozoan is knocking off tadpoles. Species vulnerable to “the beast” belong to the genus Rana, which includes leopard frogs, green frogs, and bullfrogs, says ecologist John C. Maerz.

His team at the University of Georgia in Athens stumbled across mass die-offs of southern leopard frog tadpoles in nearby ponds last year. Dissection showed the animals’ innards peppered with spherical, one-celled parasites. Genetic testing confirmed these are loosely related to Perkinsus, a disease-causing organism that affects marine shellfish.

Maerz’ group now offers the first published photos of the pathogen and descriptions of its effects in the September EcoHealth. Infected tadpoles become lethargic and developmentally stunted, the Georgia scientists report. Although the mystery parasite infects all organs, it clusters in the liver, sometimes tripling that organ’s size and giving the false impression that an animal is fat and robust. So many protozoa swamped and killed tissue in the liver of one sick tadpole, Maerz recalls, that throughout most of the organ “we could find no identifiable liver cells.”

He notes that his team did not discover the pathogen. It was first found by veterinary pathologist D. Earl Green of the National Wildlife Health Center in Madison, Wisc., part of the U.S. Geological Survey.

Since 1999, Green has quietly been recording a steady and growing incidence of the novel infection in frogs sent to his lab. All came from east of the Mississippi except for two outliers: frogs from Alaska’s Kenai Peninsula, several years ago, and one sample that he ran across 3 weeks ago from the West Coast.

Fueled by warm weather, “this infection kills steadily and slowly over the course of summer,” Green says. Although it targets tadpoles, there’s a chance that adults could also carry it and serve as amphibian Typhoid Marys.

When Green can steal a moment, he intends to publish his experiences with the pathogen-and name it. But that may require yet a bit more information on the shape of its mitochondria, explains Sanford H. Feldman of the University of Virginia in Charlottesville, a collaborator on Green’s studies. Feldman says his work indicates that “this wicked-looking organism is very primitive” and appears to “phylogenetically sit at the spot where animals and fungi diverged.”

It’s one of only three infectious agents capable of causing large die-offs of amphibians-almost all of which are in decline the world over. To date, the new protozoan has been reported only in the United States, Green says, where it has emerged as the “principal threat” that could lead to extinction of the Mississippi gopher frog. This amphibian’s sole wild population breeds in only one infected pond, where for at least 4 years virtually all tadpoles have died.

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References:

Davis, A.K. . . . and J.C. Maerz. 2007. Discovery of a novel alveolate pathogen affecting southern leopard frogs in Georgia: Description of the disease and host effects. EcoHealth 4(September):310-317. Abstract available at
http://dx.doi.org/10.1007/s10393-007-0115-3.

Green, D.E., S.H. Feldman, and J. Wimsatt. 2003. Emergence of a Perkinsus-like agent in anuran liver during die-offs of local populations: PCR detection and phylogenetic characterization. Proceedings of the American Association of Zoo Veterinarians 2003:120-121.

Climate, Fire, & Western Forests

By postMigrator November 29, 2007 November 29, 2007 Uncategorized

2004
“Montana is the most sensitive, with the models predicting a 5-fold increase in mean area burned over the observed range in climate, the authors write.”

“More frequent, more extensive fires in forest ecosystems will likely reduce the number and size of patches of older forests, the authors say. Corridors of wild areas between forests, through which species might migrate if their home territory goes up in flames, also could be affected, possibly eliminated.”

Science Daily Web address:

Modest Climate Change Could Lead To Substantially
More And Larger Fires ScienceDaily (Sep. 1, 2004)
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2006
“The increases in fire extent and frequency are…most pronounced for mid-elevation forests in the northern Rocky Mountains.”

“Lots of people think climate change and the ecological responses are 50 to 100 years away. But it’s not 50 to 100 years away–it’s happening now in forest ecosystems through fire.”

“The researchers found that 56 percent of the wildfires and 72 percent of the total area burned occurred in early snowmelt years. By contrast, years when snowmelt happened much later than average had only 11 percent of the wildfires and 4 percent of the total area burned.”

ScienceDaily Web address:

More Large Forest Fires Linked To Climate Change ScienceDaily (Jul. 10, 2006)

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Climate Change, Bears, & People

By postMigrator November 29, 2007 November 29, 2007 Uncategorized

Tuesday, November 20, 2007
WILDLIFE: Warm weather causing conflicts between bears and people (11/20/2007)

Higher-than-normal temperatures in the Western states are being blamed for increased bear activity and conflicts with people. Wildlife managers say 59 bears in Colorado alone have been put down this year due to a berry-killing drought and a late spring freeze that has forced bears into increased confrontations with humans. The previous record number of nuisance bears killed in Colorado was 55, in 2002.

Other Western states like Alaska, Idaho, Montana and Nevada also have experienced increased conflicts. An 11-year-old boy was killed by a bear at a Utah campground in June.

With temperatures as high as 10 degrees above normal, many bears are trolling cities for food rather than settling into their winter dens. “If we get a good blast of snow here it would put an end to it for this year,” said Tyler Baskfield, spokesman for the Colorado Division of Wildlife, who added that most bears already have entered hibernation. Wildlife managers in Colorado will meet in January to examine areas where the most confrontations occur and determine whether specific measures need to be taken to reduce conflicts, including an increase of fall hunting licenses for bears.

The Colorado Wildlife Commission will decide what to do in March (Robert Weller,
AP/Anchorage
Daily News, Nov. 19). —
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