pressure
of CO2 in the medium is higher at 30 °C than at 35 °C,
leading to a higher concentration of bicarbonate and consequently
an increased rate of photosynthesis. Another factor
that should be considered is that at higher temperatures (i.e.
35 °C) there is an increase in dark cycle respiratory activity
in which the cells use reserve material (e.g. carbohydrates)
for respiration and a concomitant decrease in cell weight
(Vonshak et al., 1982). According to Torzillo and Bernardini
(1991), for outdoor cultures of Spirulina up to 34% of
the biomass produced during the daylight period may be
lost through respiration at night