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Establishment of Microbial Eukaryotic Enrichment Cultures from a Chemically Stratified Antarctic Lake and Assessment of Carbon Fixation Potential
Published on: April 20, 2012
An early-branching microbialite cyanobacterium forms intracellular carbonates
Estelle Couradeau1, Karim Benzerara, Emmanuelle Gérard
1Institut de Minéralogie et de Physique de la Matière Condensée, CNRS UMR 7590, Université Pierre et Marie Curie, Paris, France.
Science (New York, N.Y.)
|April 28, 2012
Summary
Cyanobacteria form intracellular calcium carbonate inclusions, revealing a new biomineralization pathway. This discovery challenges the view of calcification as solely extracellular, expanding knowledge of microbial roles in geochemistry.
Area of Science:
- Geomicrobiology
- Biomineralization
- Cyanobacterial Research
Background:
- Cyanobacteria significantly influence Earth's geochemical cycles, including carbon, nitrogen, and oxygen.
- Calcification, the formation of calcium carbonates, is a key process historically viewed as extracellular.
- Microbialites are structures formed by microbial communities, often involving calcification.
Purpose of the Study:
- To investigate novel calcification pathways in cyanobacteria.
- To identify and characterize cyanobacteria involved in biomineralization within modern microbialites.
- To explore the cellular control mechanisms in microbial carbonate formation.
Main Methods:
- Field sampling of microbialites from Lake Alchichica, Mexico.
- Isolation and phylogenetic analysis of cyanobacteria.
- Characterization of intracellular inclusions using microscopy and chemical analysis.
Main Results:
- Identification of a cyanobacterium within the Gloeobacterales order forming intracellular amorphous calcium carbonate inclusions.
- Inclusions average 270 nm in diameter and contain calcium, magnesium, strontium, and barium.
- The composition and structure suggest controlled biomineralization within the cell.
Conclusions:
- A previously unknown pathway for intracellular calcification by cyanobacteria has been discovered.
- This finding expands the known diversity of organisms capable of forming amorphous calcium carbonates.
- Cellular control over biomineralization in cyanobacteria is demonstrated, impacting our understanding of microbial geochemistry.
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