Pumping up poison ivy.
The potential for misery might get even worse. A new study suggests that rising levels of the gas carbon dioxide in the atmosphere could make poison ivy grow faster and become more toxic.
"Rising carbon dioxide can favor pests and weeds, those plants we'd least like to see succeed," says climate-change ecologist Bruce Hungate of Northern Arizona University in Flagstaff.
Large doses of carbon dioxide (C[O.sub.2]) get into the air when people burn coal, oil, natural gas, and other fossil fuels. Carbon dioxide is a greenhouse gas. As it accumulates, the atmosphere traps more heat, and Earth's climate warms up.
Plants need C[O.sub.2] to grow. To test whether extra C[O.sub.2] in the environment leads to extra plant growth, scientists have set up circles of pipes as high as treetops around the world. These pipes spit out either regular air or extra C[O.sub.2] over a patch of ground. As a result, researchers can compare how plants respond to different atmospheric conditions.
For 6 years, scientists monitored plants that grew near some of these pipes in a Duke University pine forest. They found that, with about 50 percent more C[O.sub.2] around, poison ivy plants were able to make more food and use water with greater efficiency.
Poison ivy plants that got the CO2 boost produced the same amount of toxic oil, called urushiol, as regular air-bathed plants. With extra C[O.sub.2], however, more of the urushiol was in a particularly toxic form and more likely to cause rashes.
Poison ivy's success in the presence of extra CO2 is just one example of how climate change might alter the dynamics of forest ecosystems, scientists say.
With more poison ivy around, it might also become harder to enjoy being in the woods. Lead researcher Jacqueline E. Mohan, for example, had never developed a rash from poison ivy before she started the study. "I get it now," she says.--E. Sohn http://www.sciencenewsforkids.org/articles/20060607/Note2.asp From Science News for Kids June 7, 2006.
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|Publication:||Science News for Kids|
|Date:||Jun 7, 2006|
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