SOME FACTORS AFFECTING THE OXYGEN PRODUCTION BY ALGAE IN A SMALL CULTURE UNIT.
NAVAL RESEARCH LAB WASHINGTON D C
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The performance of an algal culture unit having a 34-inch annular culture chamber has been evaluated in terms of its oxygen-producing capabilities. The oxygen production of cultures containing 0.5, 0.6, 0.7, and 1.0 percent of cells was determined at several light intensities. For a given light intensity, the rate of output was essentially the same for each cell density, indicating that all the cultures were in the linear phase of growth. The experimental results led to the conclusion that, for cultures in the linear phase of growth, the rate of oxygen evolution is a logarithmic function of light intensity. In these studies both urea and nitrate were used as nitrogen sources. Higher growth rates were obtained when urea was used, but more oxygen was produced by nitrate-grown cultures. In addition, the average photosynthetic quotient was significantly higher for nitrate cultures. These observations can be explained by assuming that the chlorophyll in the cells photochemically reduces the nitrate, releasing oxygen in the process Hill reaction. A preliminary study concerning the nutrient requirements of the cells has shown that the nitrogen source is the first culture nutrient to be depleted. This result was not unexpected considering the high requirement of nitrogen for the synthesis of cell material. Author