Foils of titanium and copper/nickel were exposed to Antarctic marine waters for periods of 15 min to 4 h during the Austral summer 1986. Some foils were exposed to subsurface water while others were inserted through the air/water interface prior to subsurface exposure. Pyrolysis/mass spectrometry was used to fingerprint surface bound organics. Attached bacteria were examined with epifluorescent and scanning electron microscopy. During the first 2 h copper/nickel accumulated significantly more pyrolysable organics than titanium. Differences in the surface bound organics on the two materials were not significant after 4 h. Throughout the exposure period higher numbers of bacteria were found attached to the titanium foils. Titanium foils that passed through the air/water interface prior to exposure showed a temporary increase in both pyrolysable organics and attached bacteria compared to identical foils exposed to subsurface waters. No significant increase in either parameter was observed on copper/nickel. Our data indicate substratum influences on the attachment of bacteria and that processes controlling bacterial adhesion to substrata in Antarctic waters occur within 15 min after the surfaces are placed in the water.