A comparison of the 14C and the oxygen methods of measuring primary productivity

The present study shows that there is a close correlation between the rates of plankton photosynthesis measured by the 14C and the oxygen methods of measuring primary productivity. The apparent photosynthesis ratio (PR) is defined as the molar ratio of the rate of oxygen production to the rate of carbon dioxide utilisation. The PR values for the tropical algal population were observed to be in the range of 1 to 2. The high PR was mainly attributed to nitrate as a nitrogen source. The mean PR values from various rivers in Terengganu; namely Sg. Nerus, Sg. Terengganu and Sg. Ibai during the survey period (July 1982 to September, 1982) were in the range of 1.23±0.112, 1.12±0.104 and 1.03±0.081 respectively. (author)