Effects of Hydrostatic Pressure on Photosynthesis and Growth of Unicellular Marine Algae and Diatoms

Carbon dioxide assimilation and light-dependent oxygen evolution has been measured at 25C with a variety of algae under various conditions of light intensity, bicarbonate concentration, oxygen tension, and hydrostatic pressure. Unicellular green, and blue green algae, diatoms, and filamentous algae have been studied. A new device which permits the measurement of oxygen evolution in closed culture at fixed oxygen tension is described. The apparatus may also be used at hydrostatic pressures up to 1000 atmospheres. It permits growth of algae in closed containers without gas phase at constant pO2. A pressure vessel was also designed which permits enzyme kinetics to be done rapidly at increased hydrostatic pressures up to 1000 atmospheres and 40C. The system can be brought to the desired pressure and monitored spectrophometrically about 10 seconds after reaction components are mixed. This permits studies of enzyme kinetics at limited substrate concentrations, on a time scale commensurate with in vivo reactions. (Author) See also AD-720 401.