Science Interviews

Science Update - Bacteria

Bob - This week for the Naked Scientists, we're going to talk not about the bacteria in your gut, but in the air all around you. As Chelsea tells us, these bacteria have become a matter of a national security.

Chelsea - If there's anthrax in the air, is it a bioterror weapon, or just a harmless, naturally occurring close relative? The Department of Homeland Security needs to know, so they asked scientists at Lawrence Berkeley National Laboratory to take stock of the air's normal bacteria population. Microbial ecologist Gary Andersen says a better sampling technique was sorely needed.

Gary - Virtually everything that has been done to date has used culture. And we know for a fact that less than 1 percent of all organisms that are in the air, like most environments, can be cultured.

Chelsea - Instead, his team used DNA microchips. They're about the size of a quarter, and capable of distinguishing thousands of bacterial species from a single gene. Their first census of the air over Austin and San Antonio found incredible diversity: about 1,800 kinds of bacteria. And the demographics were by no means static.

Gary - We see that the bacterial organisms in the air change and respond to environmental conditions. When the temperature of a typical week was warmer or windier, we had completely different types of organisms that were present than during other meteorological conditions.

Chelsea - By understanding natural variations like these, and eventually expanding the census nationwide, the scientists hope to get the first reliable baseline of airborne bacteria. This can be useful not only for spotting possible terrorist attacks, but also for watching how global warming and climate change can affect the microbes in the air, and potentially, the public health.

Bob - Thanks, Chelsea. And we have some other news about our air. Thanks to a massive international effort, the atmosphere's damaged ozone layer is just starting to heal. Now, scientists have a better way to check up on it. Physicist Eric Muller of Lockheed Martin Coherent Technologies in Colorado has helped develop a laser-enhanced satellite system for measuring an atmospheric chemical called OH. Muller explains that OH is not only a key marker of the ozone layer's health -- it's also useful for validating scientific models of the whole atmosphere.

Eric - It turns out that how good the model is at predicting OH tells you a lot about how good the model is at predicting all kinds of other things.

Bob - And having reliable models will be critical in deciding how to respond to complex phenomena like global warming.

Chelsea - Thanks, Bob. Next time we'll talk about new research that shows that tiny distractions can be worse for your focus than big ones. Until then, I'm Chelsea Wald.

Bob - And I'm Bob Hirshon, for AAAS, The Science Society. Back to you, Naked Scientists.

January 2007