When the magnification was increased up to 10,000, differences
between AS and R1–R2 pictures were clearly appreciated
(Fig. 2). Long rod-shaped bacteria were the dominant morphotypes
in AS-picture and they appeared embedded inside a matrix of
mudding aspect. A different fact was elucidated in pictures corresponding
to R1 and R2, where rods and cocci were the predominant
bacteria morphotypes and they were loosely distributed in
the surface. Even more detailed SEM pictures (mag. 20,000) are
shown in Fig. 3. Pictures A–C present bacilli-shaped bacteria and