Have you ever wondered why soil smells the way it does?

There is a reason why earth smells the way it does...

S. griseus makes soil smell "earthy" because it produces a vocatile metabolite, geosmin.  Geosmin, litterally meaning "earth smell," is an organic compound with a smell that is extremely which the human nose is very sensitive to.  It is released when S. griseus and other microbes.

This is what Geosmin looks like:   (answers.com)

Streptomyces griseus is also involved in an interesting symbiotic relationship with an ant species from the genus Attini.  These ants cultivate fungus in a "fungal garden."  They resemble human farmers because they weed and nuture their gardens just as we do.  The bacterium resides on the ant's cuticles and helps in weeding these fungal gardens. S. griseus produces certain special toxins that help keep the main weed, called Escoropsisl, a fungus, at bay.

These are some Attine ants..

(copied from tolweb.org)

This is a large fungal garden produced by the ants...

(copied from zi.du.dk.)

Created by Cbass