Observations On Subsurface Distributions Of Chlorophyll a And Phytoplankton Carbon In The Northeast Pacific Ocean

Abstract

Measurements of subsurface concentrations of chlorophyll a and phytoplankton carbon were made between Vancouver Island and Hawaii during summer 1971. In general, chlorophyll a concentrations increased and concentrations of phytoplankton carbon decreased from 10 m to depths varying between 100 and 150 m. These distributions indicated that cellular contents of chlorophyll a increased as cells were exposed to diminishing daily irradiations. Daily compensation irradiations for net photosynthesis of subsurface phytoplankton in the northeast Pacific Ocean were estimated in summer 1973. Values ranged between 0.5 and 0.7 cal cm⁻² but variability among replicates was large giving a range of 0 and 1.2 cal cm⁻². It was not possible to correlate compensation irradiations with taxonomic composition of phytoplankton populations.