Primary production of phytoplankton (C-14) was obtained at coastal, mid-shelf and oceanic stations off the Southeastern Brazil, with the in situ simulated method. Productivity rates in the euphotic zone were calculated at two stations using chlorophyll and light data and the results were 35% lower than those obtained by the simulated in situ method. Primary production rates varied from 0.04-0.49 gC/m²/d in winter 1982, and from 0.1-032 gC/m²/d in autumn 1983. In addition, photosynthetic characteristics of the phytoplankton were studied. The P x I curves and the vertical distribution of assimilation number indicated a better photoadaptation of the sub-surface phytoplankton in relation to the surface populations.
Phytoplankton; Primary production; Photosynthesis; Southeastern Brazil