A research group at the Hall of Global Environmental Research and Graduate School of Human and Environmental Studies of Kyoto University announced on April 10, 2007, that it had discovered a new mechanism of photosynthesis that utilizes near-infrared light for water oxidation. This finding is expected to offer a new perspective on primary productivity and the carbon cycle on Earth.

Chlorophyll a (Chl a), a photosynthetic pigment, has long been seen as essential for photosynthetic reactions, since it captures visible red light and uses the energy to generate high electric potential in water oxidation. The researchers discovered that a marine cyanobacterium contains another type of pigment, Chlorophyll d (Chl d), which is capable of absorbing invisible near-infrared light and conducting water oxidation processes with less energy than Chl a. This reaction system is unique to Chl d among other photosynthetic organisms. The study demonstrated the basic mechanism of how the reactions of oxygenic photosynthesis take place and the possibility that Chl d may be used in artificial photosynthesis.

The findings also indicated that the range of wavelengths used for photosynthesis is wider and that cyanobacteria live in a larger area than previously believed. Estimates of the oceans' primary productivity (amount of the carbon sequestered through photosynthesis by phytoplankton) are likely to be modified from the current estimates at roughly 50% of primary productivity on land.

http://www.pnas.org/cgi/reprint/104/17/7283
http://www.ges.kyoto-u.ac.jp/english/index.html

Posted: 2007/08/18 10:19:53 PM
Japanese version

TAG Ecosystem , University/Research institute