Chlorophyll F is a photosynthetic pigment which is able to capture light energy in the infrared spectrum. Chlorophyll F has an absorption peak of 706 nanometers, a segment of light which was previously considered to weak to drive photosynthesis. The discovery of Chlorophyll F is the first new chlorophyll pigment discovered in almost 60 years and it stretches out the full gamut of what we call “PAR” for the organisms which contain it.
Chlorophyll F was discovered from ground up stromatolites, colonies of rock forming shallow water bacteria which have been reef building since way before corals. Although we won’t find any stromatolites growing inside our corals, it is possible that some endosymbiotic bacteria that use Chlorophyll F could be living inside corals. In 2004 it was discovered that Montastrea cavernosa does harbor some nitrogen fixing cyanobacteria and in 2008, high densities of Cyanobacteria were found living adjacent to zooxanthellae in shallow water Acropora on the Great Barrier Reef.So does that mean that SPS enthusiasts should whip out all the IR heavy metal halides again?
Although Chlorophyll F has not yet been discovered in the bacteria living inside of corals, we’d hedge our bets that some very interesting discoveries will be made once researchers start applying the right tools. It only makes sense that shallow water creatures would evolve to be able to use the abundantly available infrared light falling on them, and we’d be surprised if corals didn’t already have some symbiotic relationships to take advantage of the photosynthetic infrared Chlorophyll F. Of course since infrared light is low energy and quickly absorbed by water, only the shallow water species of corals would be able to take advantage of Chlorophyll F, if it indeed occurs inside of corals.