July 11, 2003, Hour One: News Roundup: Urban Tree Growth / Clownfish Cliques / West Nile Virus

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Science Friday > Archives > 2003 > July > July 11, 2003:
Hour One: News Roundup: Urban Tree Growth / Clownfish Cliques / West Nile Virus

Though for many of us, the summer may be a time for taking it easy, the world's scientists have been working overtime. In this hour of Science Friday, we'll take a look at some of the news in science, technology, medicine and the environment from the past week.

Though some might be surprised that trees can grow in Brooklyn, research released this week adds an unusual twist. Certain trees may actually be able to grow better in urban environments than in rural ones, if all other factors are accounted for. "We grew the same cottonwood clone in urban and rural sites and found that urban plant biomass was double that of rural sites," wrote Jillian Gregg and colleagues in a paper released this week in the journal Nature. They attribute their finding to higher levels of ozone in the rural areas. However, other plant species may not be as sensitive to the role of ozone -- and real-world plants in urban environments have many other stresses to contend with. We'll find out more.

Then, we'll talk about the strange social life of the clownfish. The yellow and white fish was the inspiration for the title character in the Disney/Pixar animated movie 'Finding Nemo' -- but this week scientists report that they have habits that might be better suited for a late-night B movie. The clownfish, researchers report in the journal Nature, has the ability to change both its size and its gender in response to changes in its social setting. "If the female of a group dies, the male changes sex and becomes the breeding female, while the largest nonbreeder becomes the breeding male," explained Dr. Peter Buston in the article. The fish maintain a well-defined size relationship within the cliques in which they live, with each fish one rung down the social ladder about 80% of the size of the fish on the rung above. When one fish becomes upwardly mobile, all the others change size as well to adjust for the new social order. We'll talk to Buston about why and how this fishy situation takes place.

And finally, we'll get an update on the West Nile virus in the United States. After arriving in the US just a few short years ago, the disease seems to have taken a solid hold in this country. Transmitted to humans from infected animals by mosquitoes, the virus causes encephalitis-like symptoms, and can be fatal. The CDC reports that as of July 9, 31 states had reported WNV activity in birds, horses, mosquitoes or humans. That number is expected to rise as the summer progresses. We'll talk about it, and what can be done to protect against West Nile.

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Guests:
Jillian Gregg
Postdoctoral researcher
Environmental Protection AgencyWestern Ecology Division
Corvallis, Ore.

Peter Buston
Postdoctoral Fellow
National Center for Ecological Analysis and Synthesis
University of California, Santa Barbara
Santa Barbara, CA

Stephen Ostroff
Deputy director, National Center for Infectious Diseases
Centers for Disease Control and Prevention
Atlanta, Georgia

Books/Articles Discussed:

"Social hierarchies: Size and growth modification in clownfish," Peter Buston. Nature 424, 145 - 146 (10 July 2003).
"Urbanization effects on tree growth in the vicinity of New York City" Jillian W. Gregg, Clive G. Jones, & Todd E. Dawson. Nature 424, 183 - 187 (10 July 2003)

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This segment produced by Adrian MacDonald