Oligotrophic and copiotrophic marine bacteria—observations related to attachment

Abstract

The initial selective adhesion of bacteria, expressing growth on solid media with low, intermediate, and high nutrient concentrations, to immersed glass surfaces in seawater was examined. Copiotrophic-type bacteria grown on high nutrient medium did not show a competitive advantage as primary colonizers. As compared to bacterial numbers in bulk water, relatively higher numbers of adhered oligotrophic-type bacteria, exhibiting growth on low-nutrient media, were found during the initial phase of adhesion. Higher numbers of copiotrophic rather than oligotrophic-type bacteria were seen in the bulk water. The majority of the adherent bacteria was irreversibly bound. Characteristics such as cell size, degree of cell surface hydrophobicity, and motility of bacterial isolates from the different nutrient concentrations did not account for the observed, possibly selective, adhesion. Although bacteria expressed nutritionally different requirements and adaptations at the time of sampling, successive reinoculations of a total of 161 isolates essentially failed to show the existence of obligacy of any given nutritional type of bacteria. The expression of different nutritional adaptations of bacteria in low-nutrient marine waters was also suggested by showing the inability of oligotrophic-like bacteria to possess starvation survival mechanisms such as those displayed by copiotrophs [3].