BACTERIAL-COLONIZATION OF ARTIFICIAL SUBSTRATE IN THE VICINITY OF DEEP-SEA HYDROTHERMAL VENTS

Artificial substrata of different material composition were deployed a t deep-sea hydrothermal areas on the Mid-Atlantic Ridge for exposure t imes ranging from 1 to 12 days. After 4 days of exposure, a very thick but loosely-bound biofilm formed on all surfaces. Two bacterial morph otypes dominated the attached microbial community: rod-shaped bacteria sometimes several cell layers thick and large filamentous forms attac hed to the substratum at one end of the filament. Quantitative extract ion of biofilm lipids associated with the substratum surface indicated the accumulation of a large amount of bacterial biomass after 4 days of exposure for all substrate. Microbial biomass accumulated at differ ent rates on the different substrata. The greatest biomass was associa ted with 316L stainless steel and titanium substrata. Polar lipid fatt y acid (PLFA) analysis of lipid extracts contained signatures of sulfa te reducing bacteria and fatty acids (FA) previously reported in filam entous sulfur-oxidizing bacteria. The results demonstrate rapid in sit u colonization of artificial substrata by hydrothermal vent microbial populations irrespective of the nature of the substratum. (C) 1998 Fed eration of European Microbiological Societies. Published by Elsevier S cience B.V, All rights reserved.