Calculating new production from nitrate reductase activity and light in the Peru current upwelling

•Realistic levels of new production were calculated by NR activity in the Peru Upwelling system.•Same distribution pattern of new production and 14C-based primary production was found.•Low temperatures recorded in September 1976 evidenced strong upwelling in the study area.•Ample of NO3− and NO2− and low NH4+ concentrations made this section an ideal research site to calculate new production.•Average values of Chlorophyll and NR were higher than they were in March 1977, for all stations.