Under ultraviolet light, massive coral skeletons reveal a series of luminescent bands that can be categorised as "bright" (yellow/green) and "dull" (blue). This work elucidates the photophysical processes that are responsible for the appearance of bright and dull bands. Samples from Papua New Guinea (subject to terrestrial inundation) and Oman (not subject to terrestrial inundation) have been investigated and compared. It has been shown that luminescent banding can be recorded directly from the surface of the coral, without the need for extraction of the component luminophores. Using 3D EEM spectroscopy, the luminescence properties of the bright and dull bands have been reproducibility characterised. Using optical fibre beam delivery, spatial resolution of the banding pattern has been achieved. The variations in intensity of luminescence along the coral core have been recorded with excellent reproducibility. The bright and dull bands observed in all samples contain similar groups of luminophores. The relative intensity of luminescence from each group varies between bands and between samples from different locations. Samples from locations with no terrestrial input exhibit similar luminescence characteristics as those that are regularly inundated with terrestrial run-off. This suggests that luminescent banding is not due solely to the incorporation of terrestrial matter into the coral skeleton. Studies have suggested that the banding pattern is also related to structural variations in the skeleton. It has been established that corals exhibit phosphorescence. The difference is phosphorescence intensity between bright and dull bands is substantially greater than the difference in total luminescence intensity. Hence, phosphorescence is an important indicator of the banding pattern and may prove to be a more valuable tool than luminescence in unravelling the environmental records stored in coral skeletons.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:663768 |
| Date | January 1999 |
| Creators | Wild, Fiona Jane |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/13232 |
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