Etude experimentale de la colonisation de surfaces par les bacteries, en eau de mer circulante

Before the building of an (OTEC) power plant, and experimental station was built near the entrance of the Bay of Brest in order to do preliminary studies. Using these facilities, the bacterial colonization of three substrata (stainless steel UB6, aluminium AG4, polycarbonate filters) was studied in an open seawater system, with a speed of 0,7 m s super(-1). The study was performed between May 1983 and May 1984, including seven experiments of 15 days each. Bacteria colonizing the metallic surfaces were counted by scanning electron microscopy, and bacteria colonizing the polycarbonate filters counted by epifluorescence microscopy. On the three substrata, bacterial colonization occurred in three successive stages: initial colonization, sometimes unsteady (about 10 super(4) bacteria cm super(-2)); intense colonization (10 super(4) bacteria cm super(-2) to about 10 super(7) bacteria cm super(-2) within one week); slow colonization beyond ten days. Although the seawater microflora of the experimental site (counted by epifluorescence microscopy) remained steady during the time of experiments, the amplitude and the duration of the different stages of colonization fluctuated according to the seasons.