“Formation of intracellular earth-alkaline carbonates by Cyanobacteria”
Event details
| Date | 27.03.2014 |
| Hour | 14:00 › 15:00 |
| Speaker | Dr. Karim Benzerara, IMPMC Paris |
| Location | |
| Category | Conferences - Seminars |
Cyanobacteria have had a pivotal role on the global cycle of carbon throughout the Earth’s history in particular by inducing the formation of carbonate deposits. Yet the mechanisms involved in carbonate biomineralization by cyanobacteria remain poorly known. For example, this process had so far been considered exclusively as an induced and extracellular biomineralization process. However, we recently discovered deep-branching cyanobacteria that form intracellular amorphous Ca-Mg-Sr-Ba carbonates [1]. These intracellular carbonates are quite different from usual carbonates: 1) They appear as nanospheres with a diameter between 100 to 500 nm; 2) They are poorly crystalline as inferred by electron diffraction; 3) They contain high concentrations of strontium and barium, much higher than in the extracellular solution suggesting a mechanism discriminating between earth alkaline elements (Ca vs. Sr vs. Ba). Several questions remain open: How significant is this process nowadays and in the past? To what extent do phases formed intracellularly by these cyanobacteria differ from abiotically formed carbonates?
In this talk, I will illustrate the analytical issues that we face when attempting to characterize these materials and their properties and will discuss in particular the use of high spatial and spectral resolution spectro-microscoscopies. Moreover, I will show some molecular biology and microbiology approaches developed to better understand this biomineralization process.
(1) Couradeau, Benzerara, Gérard, Moreira, Bernard, Brown Jr.., López-García (2012) Science 336, 459-462.
In this talk, I will illustrate the analytical issues that we face when attempting to characterize these materials and their properties and will discuss in particular the use of high spatial and spectral resolution spectro-microscoscopies. Moreover, I will show some molecular biology and microbiology approaches developed to better understand this biomineralization process.
(1) Couradeau, Benzerara, Gérard, Moreira, Bernard, Brown Jr.., López-García (2012) Science 336, 459-462.
Practical information
- Informed public
- Free
- This event is internal
Organizer
- Laboratory of Biological Geochemistry
Contact
- Prof. Anders Meibom