Figure 4.

Mass spectrum of deuterated chlorophyll a extracted from cells grown in 30% (A), 50% (B), and 70% (C) D₂O-seawater KES medium under far-red light conditions for 4 weeks. The envelope formed by the empty bars represents the simulated mass spectra with the predicted deuterated rate of Chl a. If 14% of the hydrogen atoms of chlorophyllide a were deuterated, the mass distribution of Chllide a would have centered at 619 m/z. If 7% of hydrogen atoms of Chl a were deuterated, the mass distribution of Chl a would have centered at 899 m/z. The atom %D is increased following the increased D₂O percentage in the KES medium.