August 20, 2010
Scientists have discovered a new form of chlorophyll, the light-absorbing molecule that plants, algae, and cyanobacteria use to perform photosynthesis. The new form, called chlorophyll f, absorbs light much closer to the infrared part of the spectrum than any of the previously-known four varieties.
Some species of bacteria are already known to use infrared light for photosynthesis, but unlike plants and cyanobacteria, these do not produce oxygen. If the new form of chlorophyll is confirmed to play a role in photosynthesis in oxygen-producing species, the discovery would imply that the photosynthetic process is more adaptable than was previously thought:
“Nobody thought that oxygen-generating organisms were capable of using infrared light, because the kind of photosynthesis that actually produces oxygen is thought to require a greater amount of photon energy from visible light,” says Samuel Beale, a molecular biologist at Brown University whose work centers in part on chlorophylls. “I think what they found here is a new modification of chlorophyll that shows the flexibility of photosynthetic organisms to use whatever light is available.”
The new kind of chlorophyll, discovered in Shark Bay off Western Australia, may shed light on how so many microbial species thrive within the extremely close quarters of a microbial mat. Says UC-Davis molecular biologist John Clark Lagarius,
“In a microbial mat, infrared light not being absorbed by other organisms in the mat may be the only wavelengths of light available to you. The implications are that this organism would occupy a critical niche and survive even though there are thousands of other organisms growing all around it.”
Read the full story at Scientific American.