What do carotenoids do for an organism?
The carotenoids, collect light in the red to yellow wavelengths chlorophyll a can’t then transfer the energy to chlorophyll a, making them the second class of photosynthetic pigments. They also absorb excess light energy and dissipate it in order to avoid damage in what is termed the Xanthophyll Cycle so their secondary function is protection. However there are over 600 known carotenoids and most are involved in nonphotosynthetic functions like coloring flowers and fruit. Red algae, Rhodophyta, use chlorophylls a plus beta-carotene and a number of unique xanthophylls (a subclass of yellow reflecting carotenoids). Carotene gives an orange tinge. Phycoerythrin reflects red light and is therefore responsible for the color of most red algae. http://www.nilauro.com/plocamium/divchar… Brown or golden Phaeophyta use chlorophyll a & c plus fucoxanthin the accessory pigment that gives the organism its yellow-brown color
