On primary production in the South Bight of the North Sea

The area of the North Sea next to the Belgian and Dutch coasts has been surveyed since January 1971. The photosynthetic capacity (potential production) of samples collected at 63 stations and 4 depths has been measured using the ¹⁴C technique.

The homogeneity of the water column was demonstrated almost everywhere. A general pattern of decrease of the potential production from the coast to the open sea was demonstrated in all seasons. Figures ranged from 3 to 30 mg C m^-3 h^-1. Primary production was also determined both by calculations, using the Steemann Nielsen (1952) formula, and by in situ measurements. The higher turbidity near the coast has proved to limit considerably the primary production. Figures usually range from 100 to 1500 mg C m^-2 day^-1.

The following topics have also been discussed: relationship between photosynthetic capacity and pigment content, transparency of the water, solar radiation, comparison between production calculated from photosynthetic capacity and production measured in situ, and nutrient uptake.