Pearls in peril: the future of pearls in a climate changed acidic ocean

Along the east coast of New South Wales, oysters such as the well-known Sydney rock oysters are farmed for food and famous for their quality.  Other lesser known oysters, such as the Pearl oyster, are farmed to make pearls which are used to make high quality pearl necklaces sold in jewellery stores.  Natural pearls form inside an oyster when a foreign object invades an oyster, cells in the oyster’s immune system respond by layering the invader with crystalline calcium carbonate, forming a pearl. 

Rising acidity of our oceans may affect the process of pearl formation.  We know already that environmental stress can supresses the immune system of oysters, but potentially it might also reduce the amount of crystalline calcium carbonate which the pearl oyster can secrete.  As the acidity of oceans increases as a result of increased carbon dioxide in the atmosphere, pearl oysters may be unable to create pearls.  Fewer layers of crystalline calcium carbonate mean less pearl lustre, vital for production of pearls of high quality.

In our experiment using special facilities at the Sydney Institute of Marine Science in Mosman, we increased the acidity of the water for seven months to determine whether this will affect of pearl formation.

Our study species is the native pearl oyster, Akoya (shown in picture) Pinctada imbricata

Name of main investigators:

Professor Pauline Ross University of Western Sydney
Dr Wayne O’Connor, New South Wales Fisheries, Department of Primary Industries
Dr Laura Parker, University of Sydney
Dr Victoria Cole, University of Western Sydney
Kerry Daley (Honours student), University of Western Sydney
John Wright (PhD student), University of Western Sydney
George Pinto (Technical assistant), University of Western Sydney


Ian and Rose Crisp Broken Bay Pearls:
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