Sydney Rock Oysters Facing Ocean Acidification

According to Parker et al. (2011), "the consequence of elevated pCO₂ on marine organisms, including the variation in response within and between species populations, is virtually unknown," and they say that "this limits our understanding of the potential for species acclimation through genetic adaptation, at the population and ecosystem level, and our ability to predict future impacts."

In order to provide a better understanding of the potential for the Sydney rock oyster (Saccostrea glomerata) to adapt to the threat of ocean acidification, Parker et al. measured the within- and between-population variability in the species' growth response to elevated pCO₂, working with oysters (denoted as wild) that they collected from intertidal and shallow subtidal habitats along the southeast coast of Australia, as well as two lines (QB and LKB) of the same species that had been selectively bred to support the country's oyster aquaculture industry.

The three Australian researchers discovered that the wild oysters experienced a 64% reduction in growth after four days of living in an elevated pCO₂ environment of 1000 ppm (with a water pH of 7.84) compared to wild oysters reared in the ambient pCO₂ environment of 375 ppm (with a water pH of 8.20), whereas the growth reduction experienced by QB oysters growing in the same two environments was 45%, and that experienced by LKB oysters was 25%. What is more, they report that the LKB oysters that were reared at elevated pCO₂ actually "grew slightly better than the wild oysters reared at ambient pCO₂."

In the words of Parker et al., "this study provides preliminary evidence that selective breeding may be a solution to 'climate-proof' important aquaculture industries from the impacts of ocean acidification." And it is indicative of the innate ability of the Sydney rock oyster to genetically adapt to ocean acidification -- on its own -- over an appropriate time scale.