In algae and bacteria

Algae come in multiple forms from multicellular organisms like kelp, to microscopic, single-cell organisms. Although they are not as complex as land plants, the biochemical process of photosynthesis is the same. Very much like plants, algae have chloroplasts and chlorophyll, but various accessory pigments are present in some algae such as phycocyanin, carotenes, and xanthophylls in green algae and phycoerythrin in red algae (rhodophytes), resulting in a wide variety of colors. Brown algae and diatoms contain fucoxanthol as their primary pigment. All algae produce oxygen, and many are autotrophic. However, some are heterotrophic, relying on materials produced by other organisms. For example, in coral reefs, there is a mutualistic relationship between zooxanthellae and the coral polyps.
Photosynthetic bacteria do not have chloroplasts (or any membrane-bound organelles). Instead, photosynthesis takes place directly within the cell. Cyanobacteria contain thylakoid membranes very similar to those in chloroplasts and are the only prokaryotes that perform oxygen-generating photosynthesis. In fact, chloroplasts are now considered to have evolved from an endosymbiotic bacterium, which was also an ancestor of and later gave rise to cyanobacterium. The other photosynthetic bacteria have a variety of different pigments, called bacteriochlorophylls, and do not produce oxygen. Some bacteria, such as Chromatium, oxidize hydrogen sulfide instead of water for photosynthesis, producing sulfur as waste.