Studies of two species of soil bacteria showed that both colonies could detect the scent of airborne ammonia.

"Ammonia is the simplest nitrogen source [needed] for bacteria to grow," said study co-author Reindert Nijland, who conducted the research at Newcastle University in the U.K.

"If they can sense ammonia and somehow migrate toward that source, that would be very beneficial."

In fact, when bacteria colonies were exposed to ammonia gas in the lab, the individual cells of each species joined together to form a slimy "biofilm."

Slime formation slowed down as the rival colonies got farther apart, suggesting the reaction is an attempt to spread out and win a turf war with nearby competitors—therby gaining access to the ammonia.

The discovery