Abstract
Surface sea waters were taken from June 1980 to November 1981 in the northern area of Hiroshima Bay. On shipboard they were each time incubated under the natural condition and the concentrations of chlorophyll a and POC were determined at about one hour intervals. POCdetri and POCphyto were evaluated from the interrelationship between POC and chlorophyll a concentrations. POCphyto/POC ratio ranged from 0.23 to 0.98 and the average value was 0.72.
In order to evaluate conveniently these fractions, a relationship between POCphyto/POC and photosynthetic activity was studied. It was found that the former could be expressed as a natural logarithmic function of the latter.
Using this equation, POCdetri and POCphyto of surface water in winter months and those of middle water were estimated. POCdetri/POC ratios of surface water in winter months were somewhat higher than those in other months. These ratios of middle water were generally larger than those of surface water.
