The cyclic voltammograms can be quite complex, for example when G. sulfurreducens was examined using cyclic voltammetery the complexity of the voltammogram was increased at lower scan rates increasing the distinguishable redox systems from 2 to 4 or more . As cyclic voltammetery has been shown to only probe the biofilm closet to the electrode, the usefulness of this technique in probing the bulk biofilm has been questioned due to significant potential gradient that maybe present in the biofilms .