Fig. 1: SEM images of biofilms on the surface of 316 S.
From: Influence of multilayer sea sand and Shewanella algae on the corrosion behavior of 316 SS

The surface of 316 SS exhibited four distinct states of marine sand coverage: (a) uncovered, and covered with (b) L-type, (c) M-type, (d) S-type sand. The samples were immersed for 3 days.