Researcher warns of 'invisible' invaders

A Michigan State University associate professor of ecology says invasive microbial invaders shouldn't be overlooked by scientists or underestimated by the public, a university release reported Tuesday.

"Invasive microbes have many of the same traits as their larger, 'macro' counterparts and have the potential to significantly impact terrestrial and aquatic ecosystems," Elena Litchman says. "Global change can exacerbate microbial invasions, so they will likely increase in the future."

The public and scientists are well-informed of the spread of Asian carp, zebra mussels and gypsy moths, but Litchman cites smaller invaders like exotic cyanobacteria, also called "blue-green algae," which have found their way into North American and European lakes, nitrogen-fixing rhizobium, a soil microorganism that has emigrated from Australia to Portugal, and a brackish diatom (a microscopic alga) that has colonized Lake Michigan, probably by way of ballast-water discharge.

"Currently, there are no published examples of the impacts of invasive nonpathogenic microbes, but there is growing evidence that they could change ecosystems in equally dramatic fashion," Litchman says.

Climate change could increase these microbial invasions, which could continue to grow as Earth's weather patterns change, Litchman says.

"Increasing air temperatures have been implicated in the spread of malaria and other pathogenic microbes into higher altitudes and latitudes," she says. "Likewise, climate change could stimulate invasions by tropical and subtropical nonpathogenic microbes into temperate latitudes."

Copyright 2010 United Press International, Inc. (UPI).