THE ABSORPTION OF OXYGEN FROM LIQUID CULTURES OF BLUE-GREEN ALGAE BY ALKALINE PYROGALLOL

SUMMARY

A mixture of pyrogallol with sodium hydroxide and sodium carbonate (2:1:1) in a separate container absorbed up to 75% of the oxygen in a bicarbonate-carbonate buffered medium with more or less no change in the pH of the medium. A system in which two test tubes were added to the culture vessel, one containing saturated sodium bicarbonate and the other pyrogallol plus sodium hydroxide gave similar results, but were not investigated further because of difficulties in handling. Optimal conditions for absorption of oxygen from 100 ml of the growth medium was 1 mMole pyrogallol +0,5 mMole sodium hydroxide + 0,5 mMole sodium carbonate. The addition of this pyrogallol to alkali ratio to cultures of two Microcystis and one Synechococcus isolate in rubber stoppered flasks gave stoichiometric increases in yield which was not due to carbonate enrichment but to a lowering of oxygen tension. The data may mean that even under relatively low light intensities (1 - 4 × 10³ ergs cm^?2 sec^?1) photooxidation occurs.