Diel variation in nitrogen fixation by a marine blue-green alga, Trichodesmium thiebautii

Abstract

A diel variation was demonstrated with respect to nitrogen fixing capacity of a marine blue-green alga, Trichodesmium thiebautii, collected from subtropical waters of the western North Pacific. A 200-fold difference was observed between day and night activities when measured at a light intensity of 12,000 lx. The pattern and extent of variation were different from diel variations reported for photosynthesis, nutrient uptake, and nitrogen fixation of natural populations of marine phytoplankton.