Chlorophylls: algae trap light energy using chlorophylls, helped out by accessory pigments.
Fucoxanthins are xanthophyll accessory pigments found in brown macroalgae and diatoms.
Phycobilins: these pigments are on membrane surfaces of red algae and cyanobacteria, redistributing light energy to the chlorophylls beneath.
Blooming lovely: the swirls of algal blooms are visible from space, often detected by increased chlorophyll in the sea. Phytoplankton bloom when nutrients, light and temperature are optimal (some are blooming poisonous).