CONTINUOUS CULTURE OF MARINE DIATOMS UNDER SILICATE LIMITATION. II. EFFECT OF LIGHT INTENSITY ON GROWTH AND NUTRIENT UPTAKE OF SKELETONEMA COSTATUM1,2

Two replicate experiments were conducted to investigate the effect of light intensity on the growth and nutrient uptake of Skeletonema costatum (Grev.) Cleve in silicate-limited continuous culture. Each experiment began with 4 identical chemostat cultures of S. costatum growing at the normal laboratory light (0.14 ly · min^?1, continuous illumination) under strong silicate limitation. Screens were placed over 3 cultures reducing them to light intensities of 0.042, 0.021 and 0.0018 ly · min^?1. Based on growth rules, nutrient uptake rates, cell morphology and chemical composition, the cultures receiving 0.021, and 0.0018 ly · min^?1 appeared to he light-limited, whereas the culture receiving 0.14 ly.