A Method for Preparing Permanent Mounts of Phytoplankton for Critical Microscopy and Cell Counting

A method is decribed for preparing permanent mounts of phytoplankton for critical microscopy and cell counting. Preserved phytoplankton are settled onto cover glasses (or slides), dehydrated by ethanol vapor substitution, and mounted in one of several ethanol-soluble resins. The resulting slides are permanent, quantitative, and of excellent optical quality. Resolution is very good and, with the appropriate resin, contrast is high enough to eliminate the need for phase shift or other contrast enhancement.