Changes in C. velia C, N, C∶N and carotenoids during a sinusoidal light∶dark cycle.

Changes in C (pg C cell⁻¹, panel A), the ratio of C∶N (mol∶mol, panel B), N quotas(pg N cell⁻¹, panel C) and the major carotenoids relative to chl a (presented as ratio per chl a, panel D) are shown. Error bars are calculated as standard deviations of n≥3 replicated. Average values (plus error bars) measured for LL (▪) and HL (□) grown C. velia are included for comparison. The dashed line shows the light intensity during the light part of the cycle, with a midday peak of 500 µmol photons m⁻² s⁻¹.