Fig. 2. Different types of chlorophylls (Chls) are used by oxygenic photosynthetic organisms. (A) The absorption spectra of Chl a, Chl b, Chl c, Chl d, and Chl f in solution. (B) Tetrapyrrole structure of the Chls; for information on the substitutions (red-colored), see a table in Croce and van Amerongen (2014). Figure modified from Croce and van Amerongen (2014, 2020).