Cells communicate by signaling molecules, begin to multiply and form a microcolony. Within the slimy matrix cells can exist in complex communities, penetrated by water columns. The slime prevents bacteria from drying out, and may also improve nutrient access and waste elimination. The biofilm also protects bacteria from antibiotics and toxins. The center of the microcolony becomes anaerobic and cells may exist in a dormant state.
Some cells break free from the biofilm and return to a free-swimming state.
These free-swimming bacteria may then establish a biofilm at another site.