What does the term 'sessile' refer to in the context of micro-organisms?

The term 'sessile' in the context of micro-organisms refers to those organisms that are attached to surfaces rather than being free-floating. This characteristic is significant because sessile micro-organisms often form biofilms, which are complex communities of micro-organisms adhering to surfaces, typically submerged in a liquid.

Being sessile allows these micro-organisms to establish a stable environment in which they can thrive and gain access to nutrients while minimizing the effects of shear stress encountered in flowing systems. Additionally, sessile micro-organisms can exhibit different behaviors and physiological states compared to their free-floating counterparts, as their attachment allows for more strategic interaction with their environment.