Acaryochloris marina is a species of unicellular Cyanobacteria that produces chlorophyll d as its primary pigment (instead of the typically used chlorophyll a), allowing it to photosynthesize using far-red light, at 700-750 nm wavelength.

Strains of A. marina have been isolated from multiple environments, including as epiphytes of red algae, associated with tunicates, and from rocks in intertidal zones (i.e.

[5] It was first discovered in 1993 from coastal isolates of coral in the Republic of Palau in the west Pacific Ocean and announced in 1996.

[7][13]) Scientists including NASA's Nancy Kiang have proposed that the existence of Acaryochloris marina suggests that organisms that use chlorophyll d, rather than chlorophyll a, may be able to perform oxygenic photosynthesis on exoplanets orbiting red dwarf stars (which emit much less light than the Sun).

[14][15] Because about 70% of the stars in the Milky Way galaxy are red dwarfs,[16] the existence of A. marina implies that oxygenic photosynthesis may be occurring on far more exoplanets than astrobiologists initially thought possible.