Efficiency of water-column light utilization in the subarctic northwestern Pacific

Abstract

Efficiency of water-column light utilization in the upper 2% light depth (ψ) tended to be high during spring and summer (means: 0.75 and 0.96 g C g Chl a-1 mol quanta-1 m2) and low during autumn and winter (means: 0.33 and 0.53 g C g Chl a-1 mol quanta-1 m2). Higher ψ values were probably due to an increase in the phytoplankton growth rate in the blooms. With the exception of bloom conditions, the ψ tended to increase with a decrease of the daily photosynthetically active radiation (PAR), and variations in the ψ in relation to the daily PAR were within the range of those summarized by Falkowski and Raven (1997). The water-column light utilization efficiency in the subarctic northwestern Pacific at the bloom times was noticed to be by far the highest in the world oceans.