RESUMEN

The model of an unstirred chemostat is generalized to that of a chemostat with time-dependent input/washout rates. The novelty of the new model is that time periodicity appears in the boundary conditions. The asymptotic dynamics of the competition between two microbial populations is determined in terms of the corresponding period map, which is shown to preserve the standard competitive ordering. It is shown that the dynamics of competition is similar to that of a chemostat with constant boundary conditions. Simple criteria for coexistence versus competitive exclusion are presented.