Microprobe techniques for determining diffusivities and respiration rates in microbial slime systems

Abstract

Abstract A microprobe electrode was used to determine dissolved oxygen concentrations near the surface and within a bacterial slime mass supplied with a continuous flow of nutrient solution. With dilute medium, the oxygen profile became level at high concentrations within the film, indicating substrate‐limited respiration. More concentrated medium caused the profile to fall to low oxygen concentrations characteristic of oxygen‐limited respiration. Oxygen responses to sudden changes in concentration of nutrient medium were measured. Estimates of microbial respiration rate and of diffusivity of oxygen were based on well‐known diffusion equations.