Boring algae

and an increased chlorophyll b to chlorophyll a ratio for better light capture in low light. Furthermore, an Ostreobium strain living in a coral skeleton, where nearly all of the red light has been captured by the zooxanthellae in the coral tissue, has been shown to have modified chlorophyll with a spectrum shifted towards far-red wavelengths. As zooxanthellae cannot use far-red light, more of it reaches the boring algae underneath.