Key marine species self-repairing, resilient to ocean acidification
The threat of increasing global carbon-emissions and ocean acidity is a growing concern. Ocean acidification has shown to be irreversible, with detrimental effects on marine animals such as corals, urchins and shellfish.
To examine the long-term effects of ocean acidification on biodiversity and the food chain, seven scholars from Hong Kong, South Korea, mainland China, and the United States carried out a two-year study on the reproduction of marine species in an acidified environment.
The team examined copepods, one of the most abundant classes of zooplankton, which play a key role in the marine ecosystem and food chain. To mimic ocean acidification, copepods were placed in water with increasing acidity (pH 8.0, pH 7.7 and pH 7.3) to evaluate the impact of acidification on their ability to reproduce.
The results showed that in an acidified environment, the fertility and sex ratio of copepods were adversely affected in the first and second generations. Importantly however, this effect was significantly restored in the third generation, demonstrating the copepods’ self-repairing ability to adapt to the changes in their environment over time.
According to Professor Rudolph Wu, Advisor in the Department of Science and Environmental Studies at EdUHK, the “self-repairing mechanism” of copepods is the outcome of epigenetic changes (i.e. DNA methylation). These changes were observed in specific regions of genes associated with reproductive resilience.
Wu pointed out that a majority of current environmental studies focus solely on the immediate impacts of ocean acidification, without looking into its transgenerational effects. “The study indicates that this mechanism may also apply to other species, providing a new perspective for future scientific research.”
The team's findings were recently published in Nature Climate Change.