The total chlorophyll (a + b) concentration in terms of absolute values, or normalized by its initial concentration, were followed through the batch experiments at different temperatures and photoperiods (Figs. 2 and 3).
At the lowest temperature tested (5 C), no net microalgal
growth (increase in chlorophyll concentration) was observed whatever the photoperiod duration (cf. B5–6, B5–12, Fig. 3). Roleda et al.
also reported low to negative growth rates for microalgal cultures at low temperatures (10C).
They reported that microalgae were just able to sustain metabolic activity, without cell
division; in some cases cell death was observed resulting in a negative growth rate. Reduced microbial activity and the absence of microalgal growth were expected at 5C.
Furthermore, the inoculum for our experiments had come from a culture at room