Growth responses of oligotrophic and heterotrophic marine bacteria in various substrate concentrations, and taxonomic studies on them

Abstract

Growth responses of oligotrophic bacteria to substrate concentrations have been investigated in comparison with those of heterotrophic bacteria. The results suggested that oligotrophs were the group which could grow and produce a perceptible turbidity in the media containing less than 10 mg peptone C/L of medium.Taxonomic studies indicated that the most abundant group in the oligotrophic bacterial flora was consistent with that in the heterotrophic bacterial flora at each sampling station. However, the relative proportion of pseudomonads in the oligotrophs was higher than that in the heterotrophs (at stations H-24, H-28, H-29, Ab-1, Ab-2, and O-4), while the relative proportion of Vibrio in the former was lower than that in the latter (at stations H-24, H-28, H-29, O-4, and O-9).