Oscillatory Variation of a Phytoplankton Population in a Tropical Ocean

Abstract

PRODUCTION in permanently stratified tropical seas removed from immediate land influence is believed to be either low and relatively uniform throughout the year^1,2 or higher in the winter than in the summer months^3,4. Most models of the production cycle in tropical oceans are based on information obtained from occasional cruises and there are relatively few extended series of year-round observations from specific localities. We have observed a hitherto unrecognized type of cycle; oscillatory variations of relatively short periodicity that are apparently independent of the annual solar cycle.