applied on periphytonweight. The effects of added filtered seawater (7/16 of 200 ml or 40ml according to the type of sampling) onDW,ASHand AFDW of periphyton were determined considering the salinity of the cleaningwater and the corresponding calibration curves (DW(g L−1)=1.17 Salinity (R2=0.99), ASH (g L−1)=0.94 Salinity (R2=0.99), and AFDW (g L−1)=0.23 Salinity (R2=0.96).