FIG 1.

A graphic view of some environmental factors that can be fundamental for biofilm formation. Upper part, particles are prime microbial resource hot spots and biofilm substrates in the ocean. Marine bacteria often swim toward and accumulate on marine particles, yet biofilm formation on these particles is subject to a trade-off: biofilm-forming species (cells in black) can achieve stable association with the nutrient-rich particle, while non-biofilm-forming species (cells in white) are inferior competitors on the particle but are ready to migrate to fresh particles. Lower part, fluid flow can have multiple effects on biofilm formation, including the promotion of surface attachment through shear trapping near a surface and the transport of compounds, such as quorum-sensing molecules, away from producing cells and toward cells located downstream.