Population dynamics and spatial distribution of microbial species in multispecies biofilms under the action of direct electric current.

Investigates the metabolism, population dynamics and spatial distribution of nitrifying bacteria and heterotrops in biofilms. Use of direct electric current and the micro-slicing technique; Inhibition of the nitrification rate by a current over 10 Am-2 at lower C/N ratios; Significant decrease in bacterial density of nitrifying bacteria in surface biofilms; Finding that an increase in current density narrowed the inner biofilm region; Changes in the density of NQ2-oxidizers and NH1-oxidizers in the surface biofilms, suggesting dectrochemical reactions at the anode; Finding that the current's effect on population dynamics and spatial distribution was less significant at larger C/N ratios.