Light-harvesting Bacterium Discovered in Yellowstone

Posted on July 26, 2007  Comments (4)

photo of Mammoth Hot Springs, Yellowstone National Park, by John Hunter

Surprising new species of light-harvesting bacterium discovered in Yellowstone

In the hot springs of Yellowstone National Park, a team of researchers has discovered a novel bacterium that transforms light into chemical energy.

Remarkably, the new genus and species Cab. thermophilum also belongs to a new phylum, Acidobacteria. The discovery marks only the third time in the past 100 years that a new bacterial phylum has been added to the list of those with chlorophyll-producing members. Although chlorophyll-producing bacteria are so abundant that they perform half the photosynthesis on Earth, only five of the 25 major groups, or phyla, of bacteria previously were known to contain members with this ability.

“The microbial mats give the hot springs in Yellowstone their remarkable yellow, orange, red, brown and green colors,” explained Bryant. “Microbiologists are intrigued by Octopus and Mushroom Springs because their unusual habitats house a diversity of microorganisms, but many are difficult or impossible to grow in the lab. Metagenomics has given us a powerful new tool for finding these hidden organisms and exploring their physiology, metabolism and ecology.”

Unexpectedly, the new bacterium has special light-harvesting antennae known as chlorosomes, which contain about 250,000 chlorophylls each. No member of this phylum nor any aerobic microbe was known to make chlorosomes before this discovery. The team found that Cab. thermophilum makes two types of chlorophyll that allow these bacteria to thrive in microbial mats and to compete for light with cyanobacteria.

This discovery is particularly important because members of the Acidobacteria have proven very hard to grow in laboratory cultures, which means their ecology and physiology are very poorly understood. Most species of Acidobacteria have been found in poor or polluted soils that are acidic, with a pH below 3. However, the Yellowstone environments are more alkaline, about pH 8.5 (on a scale of 1 to 14). Bryant noted, “Judging from their 16S rRNA sequences, the closest relatives of Cab. thermophilum are found around Mammoth Hot Springs in Yellowstone and hot springs in Tibet and Thailand. As we look more closely, we may find relatives of Cab. thermophilum in the microbial mats of thermal sites worldwide.”

Photo of Mammoth Hot Springs, Yellowstone National Park by John Hunter.

Related: Yellowstone National Park Photo EssayBacterium Living with High Level RadiationWhere Bacteria Get Their Genes

4 Responses to “Light-harvesting Bacterium Discovered in Yellowstone”

  1. CuriousCat: Scientists Chart Record Rise in Yellowstone Caldera
    November 10th, 2007 @ 5:13 pm

    “The floor of Yellowstone National Park’s gigantic volcano has been rising at a record rate in recent years, probably due to an underground blob of molten rock more than 14 times the size of Billings…”

  2. CuriousCat: Who Should Profit from Yellowstone’s Microbes
    November 23rd, 2007 @ 4:38 pm

    “Yellowstone’s hot waters are yielding remarkable new microbial specimens with implications for medicine, agriculture and energy, as well as offering clues to the formation of earliest life on Earth…”

  3. Anonymous
    July 21st, 2008 @ 11:14 pm

    Can they grow underwater acidobacteria in labs yet? I remember when I was in college I worked in a pharmaceutical lab where we tried to synthesize a chemical (20s proteasome inhibitor I believe is what it was called) found in acidophiles found deep in the ocean since the chemical showed positive benefits towards autoimmune diseases. We had a tough time completing the final cyclization reaction and many people thought we might be better off growing the organic matter in the lab but people were not sure it was economically feasible nor possible at the time. I wonder what ever happened to that or if growing the bacteria is possible at this point. Either way, this blog of yours is very interesting and satisfies my scientific curiosities that I don’t seem to get to spend much time on now that I moved to a totally different industry. Keep up the good work.

  4. How Wolves Changed the Yellowstone Ecosystem » Curious Cat Science Blog
    February 22nd, 2014 @ 10:31 am

    A great short video explaining the dramatic changes to the Yellowstone ecosystem with the re-introduction of wolves. Even the rivers changed…

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