11 



Preface 



Plankton studies were initiated, in 1957 under the direction of Dr. Clarence M. 

 Tai z veil and Dr. C. Mervin Palmer. The studies which they initiated were a part 

 of the Public Health Service program to collect basic data on the quality of 

 water in major waterways . In the beginning plankton studies were limited to 

 Sedgwick-Rafter counts of phytoplankton and zooplankton. As the phytoplankton 

 populations at the various stations were characterized, the dominat role of 

 the diatoms became apparent, and preparations were begun for more intensive 

 work with these forms. After the early species identifications were made 

 through consultations or correspondence with Dr. Matthew Hohn, Dr. Charles 

 Reimer, Dr. Friedrich Hustedt, and Dr. G. D. Hanna, routine diatom species 

 identification and enumeration were inaugurated in 1959 by Dr. Louis G. Williams, 

 who was in charge of plankton studies from September 1958 to December 1962. 

 Di- Cornelius I. Weber assumed responsibility for the plankton studies in 

 September 19&3- 



Mr. Louis Grivetti who was on the staff of the plankton laboratory from 

 1962-196^ developed the first draft of this guide to consolidate information 

 which would be helpful to beginners in diatom identification work. The 

 present form of this guide is the result of extensive additions and revisions 

 by Dr. Weber and his staff. 



The diatom studies have become a vital part of the plankton program. 

 The specificity of the diatom data has rendered it especially useful in 

 characterizing water quality. 



Joseph B. Anderson 



In Charge, Aquatic Biology 



