A modification of the Utermohl sedimentation technique for improved identification and cell enumeration of diatoms and silica-scaled Chrysophyceae

The method described uses the removable tower on standard Utermöhl sedimentation chambers to introduce treatment solutions to the sample with minimal disturbance to cell distribution. A weak solution of sodium hypochlorite was used to remove and clean scales from silica-scaled Chrysophyceae and to clarify diatom frustule detail. This procedure increases precision of identification and enumeration of these species over previous methods.