Air Date: Week of May 23, 2003

Living on Earth’s Cynthia Graber reports that bacteria might help protect Europe’s statues and buildings.

Transcript

CURWOOD: Coming up: immigration pressures and the response of the environmental movement.

First, this Note on Emerging Science from Cynthia Graber.

[MUSIC: Science Note Theme]

GRABER: Picture a European city with limestone sculptures adorning streets and buildings. Now, imagine what the city might look like without these works of art.

They are threatened by pollution. Acid rain that gets in the pores of the stone eats away at the grains. Previous attempts to protect statues by coating them clogs those pores, trapping moisture inside. When the moisture froze, the statues cracked.

Now, two scientists in Spain have turned to some microbes for a solution. They knew that one type of common garden bacteria exudes the mineral calcium carbonate which is similar to the stone found in the statues.

So, they took pieces from the cathedral in Grenada, Spain and immersed them for 30 days in a bath containing the bacteria. At the end of that month, the microbes had worked their way half a millimeter into the limestone where their mineral deposits acted as a bio-mortar, coating and strengthening the original grains.

Researchers hope to one day spray threatened sculptures or wrap them in bacteria-soaked cloth. But they say they’ll proceed cautiously. Previous attempts to use bacteria to cure acid rain erosion left statues slimy or discolored.

That’s this week’s Note on Emerging Science. I’m Cynthia Graber.

[MUSIC]

CURWOOD: And you’re listening to Living on Earth.

[MUSIC: Erroll Garner “Tea For Two” That’s My Kick and Gemini - Ocatve (1994)]