Confocal scanning laser microscopy was used to microscopically observe
a partially degraded compost particle. When compared to typical epifl
uorescence microscopy, significant heterogeneity in the biofilm was ob
served. In contrast to many reports, which assumed a uniform biofilm o
n the surface of a particle, individual colonies could be observed whi
ch penetrated the particle for significant depths. By analyzing these
confocal images with the software NIH Image, the depth of the biofilm
can be clearly observed. The implications of this nonhomogeneous biofi
lm are discussed.