One of the most important aspects in the research on reef-building corals is the process by which corals accrete biogenic calcium carbonate. This process leads to the formation of a mineral/organic composite and it is believed that the development of the nano- and microstructure of the mineral phase is highly sensitive to the growth conditions.
Transmission electron microscopy (TEM) analysis of large-scale (10 × 30 μm) focused ion beam (FIB) prepared lamellae was performed on adult and juvenile scleractinian coral skeleton specimens. This allowed for the investigation of the nano and microstructure and the crystallographic orientation of the aragonite mineral. We found the following microstructural evolution in the adult Porites lobata specimens: randomly oriented nanocrystals with high porosity, partly aligned nanocrystals with high porosity and areas of dense acicular crystals of several micrometers extension, the latter two areas are aligned close to the [0 0 1] direction (Pmcn space group). To the best of our knowledge, for the first time the observed microstructure could be directly correlated with the dark/bright bands characteristic of the diurnal growth cycle. We hypothesize that this mineral structure sequence and alignment in the adult specimen is linked to the photosynthetic diurnal cycle of the zooxanthellea regulating the oxygen levels and organic molecule transport to the calcifying medium. These observations reveal a strong control of crystal morphology by the organism and the correlation of the accretion process.
No indication for a self-assembly of nanocrystalline units, i.e., a mesocrystal structure, on the micrometer scale could be found.
van de Locht R., Verch A., Saunders M., Dissard D., Rixen T., Moya A. and Kröger R. (2013) Microstructural evolution and nanoscale crystallography in scleractinian coral spherulites. Journal of Structural Biology 183(1): 57-65. 10.1016/j.jsb.2013.05.005
@article{van de Locht2013,
Title = {Microstructural evolution and nanoscale crystallography in scleractinian coral spherulites},
Author = {van de Locht, Renée and Verch, Andreas and Saunders, Martin and Dissard, Delphine and Rixen, Tim and Moya, Aurélie and Kröger, Roland},
Editor = {},
Journal = {Journal of Structural Biology},
Year = {2013},
Pages = {57-65},
Volume = {183},
Doi = {10.1016/j.jsb.2013.05.005},
Abstract = {One of the most important aspects in the research on reef-building corals is the process by which corals accrete biogenic calcium carbonate. This process leads to the formation of a mineral/organic composite and it is believed that the development of the nano- and microstructure of the mineral phase is highly sensitive to the growth conditions.
Transmission electron microscopy (TEM) analysis of large-scale (10 × 30 μm) focused ion beam (FIB) prepared lamellae was performed on adult and juvenile scleractinian coral skeleton specimens. This allowed for the investigation of the nano and microstructure and the crystallographic orientation of the aragonite mineral. We found the following microstructural evolution in the adult Porites lobata specimens: randomly oriented nanocrystals with high porosity, partly aligned nanocrystals with high porosity and areas of dense acicular crystals of several micrometers extension, the latter two areas are aligned close to the [0 0 1] direction (Pmcn space group). To the best of our knowledge, for the first time the observed microstructure could be directly correlated with the dark/bright bands characteristic of the diurnal growth cycle. We hypothesize that this mineral structure sequence and alignment in the adult specimen is linked to the photosynthetic diurnal cycle of the zooxanthellea regulating the oxygen levels and organic molecule transport to the calcifying medium. These observations reveal a strong control of crystal morphology by the organism and the correlation of the accretion process.
No indication for a self-assembly of nanocrystalline units, i.e., a mesocrystal structure, on the micrometer scale could be found.},
}
TY - JOUR
AU - van de Locht, Renée
AU - Verch, Andreas
AU - Saunders, Martin
AU - Dissard, Delphine
AU - Rixen, Tim
AU - Moya, Aurélie
AU - Kröger, Roland
TI - Microstructural evolution and nanoscale crystallography in scleractinian coral spherulites
T2 - Journal of Structural Biology
PY - 2013
SP - 57-65
VL - 183
DO - 10.1016/j.jsb.2013.05.005
AB - One of the most important aspects in the research on reef-building corals is the process by which corals accrete biogenic calcium carbonate. This process leads to the formation of a mineral/organic composite and it is believed that the development of the nano- and microstructure of the mineral phase is highly sensitive to the growth conditions.
Transmission electron microscopy (TEM) analysis of large-scale (10 × 30 μm) focused ion beam (FIB) prepared lamellae was performed on adult and juvenile scleractinian coral skeleton specimens. This allowed for the investigation of the nano and microstructure and the crystallographic orientation of the aragonite mineral. We found the following microstructural evolution in the adult Porites lobata specimens: randomly oriented nanocrystals with high porosity, partly aligned nanocrystals with high porosity and areas of dense acicular crystals of several micrometers extension, the latter two areas are aligned close to the [0 0 1] direction (Pmcn space group). To the best of our knowledge, for the first time the observed microstructure could be directly correlated with the dark/bright bands characteristic of the diurnal growth cycle. We hypothesize that this mineral structure sequence and alignment in the adult specimen is linked to the photosynthetic diurnal cycle of the zooxanthellea regulating the oxygen levels and organic molecule transport to the calcifying medium. These observations reveal a strong control of crystal morphology by the organism and the correlation of the accretion process.
No indication for a self-assembly of nanocrystalline units, i.e., a mesocrystal structure, on the micrometer scale could be found.
ER -
