GAS EXCHANGE WITH MASS CULTURES OF ALGAE. II. RELIABILITY OF A PHOTOSYNTHETIC GAS EXCHANGER.

Comparisons of oxygen production and carbon dioxide absorption by an algal gas exchanger were made over a 3-month period. The data do not represent a continuous test, but they do represent results obtained when identical light intensities, CO(2) supply rates, and dilution rates with fresh culture medium had been used for more than 1 day. Steady-state conditions were thus assured, and the agreement in the data was excellent. Under the same experimental conditions, the unit was operated continuously for a 5-day period, and the daily variability in this test was less than in the results obtained from month to month. The variation between the average O(2) production during the 5-day test and the average of the tests over a several-month period was less than 3%. It is concluded, therefore, that the reliability of the algae in producing oxygen is sufficient to warrant their use in either submarine or space ship use.