Fig. 2
The Sabellaria alveolata bioconstruction of the Ostia area. (a) September 2013: the morphology of the bioconstruction is irregular; the silver metal frame (20 × 20 cm2) on the S. alveolata bioconstruction is shown; (b) March 2014: the bioconstruction morphology seems unchanged; (c) June 2014: details of the bioconstruction with sectors of mussel (in black) recruitment; (d) August 2014: details of surfaces that seem to be regularized by erosion (see the top right and bottom left corners of the picture)