ABSTRACT
While fluorescent staining and counting under epifluorescence microscopy has become a standard method for enumerating bacteria, no single method for measuring bacterial cell volume has been adopted as a standard. Microscope methods most widely used for measuring bacterial cell size include epifluorescence microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The general advantages of microscope methods are that they are direct and specific for bacteria and that the basic underlying assumptions for estimating biomass from biovolume are few and relatively simple. The limited resolution of light microscopes makes precise and accurate size measurements of small natural bacteria difficult. The microscope preparations made for counting may also be used for sizing of bacteria. The TEM offers the same high resolution as the scanning electron microscope but the sample preparation is more simple and there is no need for metal coating of the preparates.
