Photo taken from: http://www.mnhn.fr/lmcm/
Cyanobacterium, which is known as blue-green algae, is believed to be the drive force for evolution of organisms breathing oxygen, which could be provided by them by taking in carbon dioxide. In the past, there were several types of cyanobacterium being discovered. But this time, Karim Benzerara, Estelle Couradeau and their team found something different.
This new cyanobacterium, which is named Candidatus Gloeomargarit lithophora, was found in an alkaline lake of Alchichica in Mexico. What made it different is, it has mineral in it made up of Calcium, Magnesium, Barium and Strontium. And these mineral with carbonate formed calcified round objects intracellularly. Now what’s the big deal?
Intracellular calcification is a feature never been discovered before this.
There were quite a number of cyanobacteria which is known to form extracellular calcification. In the process of converting Carbon dioxide to oxygen, cyanobacteria may turn to other sources like bicarbonate for photosynthesis when dissolved inorganic carbon is scarce. Conversion of carbon dioxide from bicarbonate raises extracellular pH, inducing the calcification through precipitation. But in Candidatus Gloeomargarit lithophora, calcified granules are, in contrast, observed inside the cell body. And since the percentage of the contents is very different from their environment, they believe the cyanobacterium has some kind of mechanism for it. At the same time, they believe, the cyanobacterium had been using such granules as a ballast to sink lower in the lake where their normal density would not have achieved.
In regard to this finding, the team believe it might be able to fill in the gap in records of cyanobacteria. Genetic analysis by the team suggested the bacterium’s ancient lieanage to the Gloeobacterales. However, such granules did not showed up in a fossil record before, hence, the team is yet to find out more about whether the granules dissolve or not after they die.
Hence, keep your heads up for more findings about the history of cyanobacteria.
Bony Bacteria: New species builds hard structures inside cells by Rachel Ehrenberg
A Hard Life for Cyanobacteria by Robert Riding in Geochemistry, Science, p. 427-428.