Some Measurements of Primary Production in East and West Okoboji Lakes, Dickinson County, Iowa

Many methods have been employed to measure the organic production of phytoplankton communities in natural waters. These methods include measurements of, (a) the ash-free weight of seston, (b) the chlorophyll content of the water, (c) phytoplankton abundance, (d) plant volume, (e) oxygen evolution, and (f) the assimilation of carbon-14. The introduction (3) of a simple technique for the application of carbon-14 to production studies has opened the way for a more direct approach to the problem. Because the significance of data obtained by the use of indirect methods is necessarily obscure, production studies frequently employ two or more methods. Although the carbon-14 method is considered to give a direct measurement of production, it was decided that a more comprehensive picture of production factors would be obtained by measuring both oxygen evolution and carbon-14 assimilation. The data reported were collected in June, July, and August of 1957, during the initial phase of a project organized in June 1957 by Dr. K. D. Carlander, Department of Zoology and Entomology, and Dr. J. D. Dodd, Department of Botany and Plant Pathology, for the purpose of measuring primary production in some Iowa lakes