Primary production in the southern Baltic Sea determined from photosynthetic light curves
Bulletin of the Sea Fisheries Institute 3 (148) 1999, pp. 23-40

Henryk Renk and STANISŁAW Ochocki
Sea Fisheries Institute, Kołłątaja 1, 81-332 Gdynia, Poland

Key words: primary production, assimilation number, photosynthetic light curve, southern Baltic.

This work presents photosynthetic light curves for phytoplankton of the southern Baltic Sea. The seasonal variability of phytoplankton assimilation numbers is described using the following formula:  ANB = 3.54 - 1.83 . sin(w. x+ 0.79) + 0.32 . sin(2w. x + 0.88). The application of parameters of the photosynthetic light curve, results of measurements of chlorophyll concentration, attenuation coefficient for scalar irradiance and the dose of PAR irradiation measured directly below the water surface to calculate primary production is presented. The results obtained are compared with the in situ measurements of the primary production. The correlation of results obtained from  in situ measurements and based on calculations using the photosynthetic light curve is good. The mean assimilation numbers determined were used to calculate the average primary production in the Gdańsk Deep and the Bornholm Deep, which are, respectively, 133 and 102 g C . m-2 . year-1.