[Coral-List] Nanoscience Investigations of Porites lutea

[Nikkita Lawton]

Dear Subscribers of Coral-List

I am studying the structure and chemistry of the coral skeleton utilising
nanoscience techniques including transmission and scanning electron
microscopy, as well as atomic force microscopy. My supervisor Dr Roland
Kroeger and I are particularly interested in looking at the calcification
process, and the role and properties of the organic matrix within this.

We are using the tripod mechanical polishing technique along with precision
ion polishing system (PIPS) to thin our specimens of *Porites lutea*.
 Before polishing, we first cure the sample in epoxy to fill the pores, to
minimise sample fragmentation during the thinning stage.   Due to the
fragile nature of the specimens including their sensitivity to high
temperatures and the electron beam, we are concerned about the production of
artefacts that occur during preparation and analysis.  We have visualised a
change in the structure under the ion beam in some cases; the coral slices
at 20 micrometres appear translucent when placed in the PIPS but after just
a few minutes at 3keV the samples appear white and opaque. Can anyone shed
some light on this interesting phenomenon?

We would appreciate any communication with individuals who have experience
in the preparation of electron-transparent coral specimens or who believe
their research complements ours.


Any suggestions on different sample preparation techniques would also be
greatly appreciated.  In addition, we are looking for sources of *Porites
lutea* material; if you can help us with this please get in touch. * *


We look forward to hearing from you.


Many Thanks


Nikkita Lawton

-

PhD Student

Department of Physics

University of York

Heslington

York

North Yorkshire

YO10 5DD


Email: nll501 at york.ac.uk