Phytoplankton responses to light variability on a diel
scale are very relevant for their dynamics as they allow
the cells to acclimate to the surrounding system and to
optimize their performance. Indeed, phytoplankton is
highly synchronized to the light–dark cycle (Vaulot et
al. 1995) and the timing of division is different in different
species and groups, and even strains (Vaulot &
Marie 1999). This variability is also responsible for
observed variations in optical properties of seawater
(DuRand et al. 2002) and is, therefore, a critical factor
to consider when estimating primary production from