... microprofiles of O2, NH4+, NO2-, and NO3- in the autotrophic nitrifying biofilm (B). The distribution and magnitude of the estimated specific rates of net consumption and production of ... The structure and principle of commonly used amperometric and potentiometric microsensors are shown in Fig.1. The spatial resolution of microsensors is about two times the tip diameter of the ... biofilm. After reaching the steady-state condition, microprofiles of NH4+, NO2-, NO3-, and O2 in the biofilms were measured by use of microsensors, and the spatial distributions of...