Bacterial primary colonization and early succession on surfaces in marine waters as determined by amplified rRNA gene restriction analysis and sequence analysis of 16S rRNA genes

The nearly universal colonization of surfaces in marine waters by bacteria and the formation of biofilms and biofouling communities have important imp lications for ecological function and industrial processes. However, the dy namics of surface attachment and colonization in situ, particularly during the early stages of biofilm establishment, are not well understood. Experim ental surfaces that differed in their degrees of hydrophilicity or hydropho bicity were incubated in a salt marsh estuary tidal creek for 24 or 72 h. T he organisms colonizing these surfaces were examined by using a cultivation -independent approach, amplified ribosomal DNA restriction analysis. The go als of this study were to assess the diversity of bacterial colonists invol ved in early succession on a variety of surfaces and to determine the phylo genetic affiliations of the most common early colonists. Substantial differ ences in the representation of different cloned ribosomal DNA sequences wer e found when the 24- and 72-h incubations were compared, indicating that so me new organisms were recruited and some other organisms were lost. Phyloge netic analyses of the most common sequences recovered showed that the colon ists were related to organisms known to inhabit surfaces or particles in ma rine systems. A total of 22 of the 26 clones sequenced were affiliated with the Roseobacter subgroup of the alpha subdivision of the division Proteoba cteria (alpha-Proteobacteria), and most of these clones were recovered at a high frequency from all surfaces after 24 or 72 h of incubation. Two clone s were affiliated with the Alteromonas group of the gamma-Proteobacteria an d appeared to be involved only in the very early stages of colonization (wi thin the first 24 h). A comparison of the colonization patterns on the test surfaces indicated that the early bacterial community succession rate and/ or direction may be influenced by surface physicochemical properties. Howev er, organisms belonging to the Roseobacter subgroup are ubiquitous and rapi d colonizers of surfaces in coastal environments.