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An apparatus to measure the rate of oxygen evolution while maintaining pO2 constant during photosynthetic growth in closed culture vessels capable of operation at increased hydrostatic pressures

A double polarographic device is described which permits regulation of dissolved oxygen concentration at any preset pO2 in suspensions or cultures of photosynthetic algae. It also simultaneously permits measurements of the rate of oxygen evolution during photosynthesis. The apparatus is designed to operate in closed vessels in the absence of a gas phase, and may be used at increased pressures tested up to 500 atmospheres. Regulation of oxygen levels was maintained constant at various preset concentrations equivalent to atmospheric pO2 values ranging between 0.02 and 0.21 at 25°C.