Cyanobacteria are oxygen-producing photosynthetic bacteria. They are the most genetically diverse and occupy a broad range of habitats across all latitudes, widespread in freshwater, marine and terrestrial ecosystems.  

Chlorophyll a is typically the major photosynthetic pigment in all oxygenic photosynthetic organisms (plants, algae and Cyanobacteria) with Chl b and c playing only an accessory light-harvesting function. One cyanobacterium Acaryochloris marina (isolated from Great Barrier Reef, Australia)contains Chl d as its major pigment (more than 99% of total chlorophyll). This is the first known example where a chlorophyll other than Chl a is involved in the primary chemical reaction in a reaction center as is the case in all other oxygenic photosynthetic organisms. The unique optical properties of Chl d allows Acaryochloris thriving in the low visible light but higher infra-red light environment.

Stromatolites are rock-like buildups of microbial mats that form in limestone- or dolostone-forming environments. Shark Bay, Australia, has abundant examples of living marine stromatolite. Recently, we have discovered the most red-shifted chlorophyll, Chl f, from stromatolites pigment extractions (Chen et al, 2010, in Science). Such microbacterial community is formed by a stacked optical series where different photosynthetic bacteria use the light that not harvested by those organisms they live spatially above them. This discovery challenges the limitation of spectral wavelength region for oxygenic photosynthesis, which may open new bioenergy applications.