Scientists collecting coral core samples
Scientists collecting coral core samples.
Image: Maris Kazmers, courtesy NOAA Palaeoclimatology

Coral is an important indicator of past rainfall and sea surface temperature.

Similarly to tree rings, the bands in the coral shell change, depending on the exposure to fresh water through rainfall, temperature and access to nutrients.

Corals record seasonal changes in the texture of the calcite within their skeletons.

Lighter coloured coral rings are created during periods of warmth, such a summer, where the coral shows intervals of rapid growth.

Meanwhile, darker layers are created during cooler periods, where the coral’s growth slows down.

As such, data from coral samples from the Great Barrier Reef, Indonseia and the south-western Pacific will be helpful in extending our palaeoclimate record for south-eastern Australia.

The coral samples will contribute to our knowledge of the cycles of cooling and warming in our region.

A slice of Great Barrier Reef coral under ultraviolet light shows annual luminescent banding that provides a history of freshwater river floods. Reproduced courtesy of Eric Matson, Australian Institute of Marine Science.
Collecting samples of fossil coral on Christmas Island.
Image: Helen McGregor, University of Wollongong