Ecological Study on Biomineralization in Pinctada fucata

Abstract

Pinctada fucata inhabits in tropical and subtropical seas, so the sea water conditions have great impacts on its growth and shell formation. To determine the potential effects of global climate change and the water pollution on the oyster growth in the near future, we have conducted a series of studies about the metabolism and shell formation of P. fucata under varied stressors. Various factors controlling biomineralization, such as genes, environmental factors, and ions that ocean acidification (OA), ocean warming (OW), and metal pollution have great effects on the metabolism, biomineralization process, as well as the immune defense, were pointed by our study. It was found that, during short-term exposure, the impact of CO2 and temperature stresses was not manifested in the shell ultrastructure, although it affected the process of biomineralization. If the stressors are present in the long-term, they will have adverse results on the biomineralization of pearls, most likely affecting pearl quality, which results in substantial economic losses for the aquaculture industry. In addition, OA and OW have a great impact on the physiological conditions of hemocytes, including altering pH value of hemolymph and increasing the total hemocyte count, total protein content, and percentage of large hyalinocytes and granulocytes, while decreasing phagocytosis ability. We query the metal accumulations and the corresponding enzymatic responses in the pearl oyster Pinctada fucata after copper exposure. We found that the gills and the digestive gland played different roles associated with distinct copper concentrations and observed the adaptation and recovery of the oysters. Our studies have indicated potential implications for predictions of the effects of environmental changes on pearl aquaculture. Moreover, it also provides theoretical basis for precautions to avoid adverse impact of environmental challenges on the marine pearl aquaculture in the near future.