BACTERIA OF SEDIMENT - EXTRACTION AND DIS TRIBUTION IN A MACROTIDAL MUDFLAT (BAY OF MONT-SAINT-MICHEL)

Several methods for dispersing sediment aggregates and separating micr oorganisms from substrate were compared for efficiency. Cation-exchang e resin with sodium deoxycholate proved to be the most efficient metho d. Recovery efficiencies were compared for cation exchange resin combi ned with sonication, for pure bacterial cultures incubated in autoclav ed sediments. Percentage recovery of bacteria with this technique was 98%. This improved method was used to determine bacterial abundance in sediments of an intertidal mudflat. Differences between Winter and Sp ring were recorded at the higher and intermediate sampling stations of the flat, but none of the lower. Temperature at bottom sediment, infl uenced by immersion period, is likely to have been a significant facto r affecting spatial distribution and temporal fluctuation of bacterial abundances.