Sporosarcina pasteurii, are known to perform CaCO₃ precipitation by hydrolyzing urea and increasing the local pH, in presence of the Ca²⁺ rich brine solution. We have developed a new electrochemical probes for scanning electrochemical microscopy (SECM) to study this calcification process in real time. We have used the newly developed ultramicrosensors, such as pH, Ca²⁺, and redox sensors, to monitor a real-time, bacteria-mediated urea hydrolysis process and subsequent changes in morphology due to CaCO₃ precipitation. We observed a rapid local (500 μm above the biofilm) pH change from 7.4 to 9.2 within 2 min of addition of urea, whereas the bulk pH remains constant at 7.5.  Similar Ca²⁺ profile was also recorded locally where the  Ca²⁺ concentration above the biofilm depleted from 170 mM to 1 mM. Recent developments regarding the real-time live biofilm morphological change correlated with the chemical (Ca²⁺ and pH) information will be presented in the meeting.