Hot Spring Cyanobacteria Grow in Near Darkness by Using Far-Red Light (VIDEO)

It turns out that some cyanobacteria can grow in near darkness, using a previously unknown process for harvesting energy and producing oxygen from sunlight. The new findings could help explain dense blooms that impact Lake Erie and other lakes worldwide.

The cyanobacteria in question is called Leptolynbya, and it completely changes its photosynthetic apparatus in order to use far-red light, which has wavelengths longer than 700 nanometers-slightly longer than the range of light that people can see. In order to better understand how this photosynthetic system works as a whole, the scientists used a variety of biological, genetic, physical and chemical experiments.

In this case, the researchers found the cyanobacteria replace 17 proteins in three major light-using complexes while also making new chlorophyll pigments that can capture the far-red light. They also use pigments, called bilins, in new ways. The organisms accomplish this feat by quickly turning on a large number of genes to modify cellular metabolism while at the same time turning off a large number of other genes; the process has now been called Far-Red Light Photoacclimation (FaRLiP).

"Our studies reveal that the particular cyanobacterium that we studied can massively change its physiology and metabolism, and its photosynthetic apparatus," said Donald A. Bryant, one of the researchers, in a news release. "It changes the core components of the three major photosynthetic complexes, so one ends up with a very differentiated cell that is then capable of growing in far-red light. The impact is that they are better than other strains of cyanobacteria at producing oxygen in far-red light, and they are better even than themselves. Cells grown in far-red light produce 40 percent more oxygen when assayed in far-red light than cells grown in red light assayed under the same far-red light conditions."

Yet this isn't the only strain that can use this type of photosynthesis. The researchers used genome-sequence analysis of different cyanobacteria strains and found 13 addition strains that could use far-red light.

"We now have clearly established that photosynthesis can occur in far-red light, in a wavelength range where people previously did not think that oxygenic photosynthesis could take place, and we have provided details about many of the process involved," said Bryant. "Our research has opened up many new questions for basic scientific research."

The findings are published in the journal Science.

Want to learn more? Check out the video below, courtesy of YouTube.