Fluctuations in population densities of Ceratium hirundinella (O. F. M.) Dujardin and Peridinium cinctum (O. F. M.) Ehrenberg were observed in a small pond in Calloway County, Kentucky in ...relationship to weekly and seasonal variations of certain ecological factors. Collections were made weekly from each of five stations from September 19, 1969 to April 29, 1970. Water samples were analyzed chemically for pH, turbidity, iron, phosphate, oxygen, hardness, carbon dioxide, and nitrate. Air and water temperatures and Secchi Disc readings were also taken. A maximum population density was observed for C. hirundinella in April while P. cinctum achieved its maximum population density in March. Oxygen, nitrate, phosphate, carbon dioxide, pH, and turbidity were determined to be non-limiting and statistically insignificant.
