Because nitrogen is the most important element contributing to
the dry weight of microalgae cells, its deprivation significantly
changed the physiological parameters (Jiang et al., 2012; White
et al., 2011). C. muelleri cultured in f/2-N medium showed a 38%
reduction in the Fv/Fm, compared to the control (Fig. 2a). The a value
was reduced by 39% under nitrogen deprivation (Fig. 2b), suggesting
that the photosynthetic efficiency was decreased. The rETR
(Fig. 2c) and Ik (Fig. 2d) were decreased by 51% and 57%, respectively.
Under nitrogen deprivation conditions, the efficiency of PS
II decreases, primarily due to the reduced photosynthetic pigments
which decreases the rate of photosynthesis (Masojídek et al.,
2000).