Fig. 2. Representative optical cross-sections through three separate intact cement disks in seawater by laser scanning confocal microscopy. The cement was visualized by auto-fluorescence. (A) Overlay of images acquired with FITC and Cy5 filter sets, (B,C) overlay of images acquired with FITC, Cy3 and Cy5 filter sets; excitation 488, 543 and 633 nm, emission filters 505-525, 560-600, and >600 nm. Scale bars, 10 µm.