PCA of biofilm community composition at site 1 using FISH counts to describe the community structure of reef biofilms. Abbreviations: 2W S and 2W D, shallow- and deep-water biofilms, respectively, developed over 2 weeks; 4W S and 4W D, shallow- and deep-water biofilms, respectively, developed over 4 weeks; 8W S and 8W D, shallow- and deep-water biofilms, respectively, developed over 8 weeks. Biplots of the response variables were overlaid on the PCA plots as vectors. A, Actinobacteria; B, Planctomycetales; C, Firmicutes; D, Archaea.