Bacterial diversity investigations were made from the shallow vent of D joao de castro, Azores, Portugal and their adaptations to a nutrient rich environment was investigated from 2004 and 2005 cruise samples. Assesment of the qualitative composition of the heterotrophic bacterial diversity studied by various means like 16S rRNA, FAME and RFLP expressed the existence of consistent bacterial groups like Bacillus, Staphylococcus, Micrococcus, Halomonas, Pseudoalteromonas, Alcaligenes and Brevibacterium. In situ studies conducted with different metals, revealed that Fe, Mn and Pb reduce the bacterial growth period by 50% in some of the speies like Staphylococcus succinus, Bacillus subtilis and Bacillus sp. About 55% of the organisms from the experimental site were able to hydrolyze carbohydrates, 27% of them were able to attack fatty acid and 45% were protein degraders. High temperatures (70 degrees C) and neutral pH (7) were opted by most of the vent bacteria to produce their enzymes. Adaptive mechanisms to detoxify the metals by producing H sub(2)S gases catalase and oxidase for decomposition of hydrogen peroxide and oxygen supply; extended survival in unfavourable conditions by sporulation were observed as a common characteristic features in most of the bacterial isolates of the shallow vent DJCS.

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