ABSTRACT
The development of environmental microsensor techniques is a revolutionary advancement in the measurement of both absolute levels and changes in chemical species in engineered and natural aquatic systems. This advancement has utilized microscopic monitoring to contribute a greater understanding of biological mechanisms in many environmental processes for decades. The needle-type electrochemical microsensor is one of the most prominent, novel methods for studying biofilms. This chapter describes needle-type environmental microsensors that can measure at high spatial resolution and that are yet sensitive enough to detect concentration changes of a target compound (or constituent) that are relevant in environmental settings. It summarizes the representative materials and equipment necessary to fabricate needle-type environmental microelectrode and MEMS sensors. The applications of environmental microsensors are demonstrated in engineered and natural stratified microbial communities e.g. nitrifying biofilm, marine sediments, activated sludge flocs, microbial mats.
