ABSTRACT: In the central North Atlantic Ocean, the ultraphytoplankton averaged over depth and season comprises 78% Prochlorococcus spp., 12% Synechococcus spp. and 10% eukaryotic algae by numbers. However, on the basis of light scatter (a substitute for carbon biomass), the average percentages are 11, 2 and 87% respectively. On the basis of red fluorescence (a substitute for chlorophyll biomass), the average percentages are 28, 11 and 61% respectively. On the basis of primary productivity, the average percentages are 19, 13 and 68% respectively. Thus, eukaryotic algae dominate the biomass and productivity of ultraphytoplankton.

KEY WORDS: Chlorophyll . Cyanobacteria . Flow cytometry . Prochlorophytes . Ultraphytoplankton

Published in MEPS Vol. 122 (1995) on June 15
ISSN: 0171-8630. Copyright © Inter-Research, Oldendorf/Luhe, 1995