On the vertical distribution of the dissolved oxygen in the ocean

Abstract

Assuming that about 90 per cent of the oxygen consumption in sea water can be attributed to the oxidation of organic carbon to carbon dioxide, the amount of carbon dioxide calculated from the oxygen consumption ( ΔC) was subtracted from the total amount of carbon dioxide present at two stations in the north-east Pacific. Upon dividing the remainder by the chlorosity, a nearly constant value was found from the surface to about 2,000 metres, giving weight to the validity of the assumption. Seasonal variations in the integrated oxygen consumption in the water column to 1,000 metres were then compared with similar variations in the volumes of plankton taken from the upper 100 metres at two stations in the western Pacific. These values were found to vary similarly throughout the year. These results, and the observations of other authors that the oxygen minimum occurs at nearly the same density in much of the ocean, lead to the conclusion that local productivity and the vertical distribution of density are important factors in determining the vertical distribution of dissolved oxygen and in accounting for the occurence of minimum oxygen concentrations at intermediate depths.