New research delivers hope for reef fish living in a high CO2 world

Chemical changes in the ocean, as a result of climate

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change, are leading to a more acidic environment, referred to as 'ocean acidification' (OA). In a laboratory setting, these changes have been shown to lead to a range of risky behaviours in the affected fish, with some fish unable to flee from their finned foes effectively.

But, when researchers recalibrated experiments to adjust for natural daily changes in concentrations of dissolved carbon dioxide (CO2), the primary chemical driver of OA, they found that the fish were less affected than previously thought.

"Shallow water habitats where reef fish live can experience substantial natural fluctuations in water chemistry throughout the day," explained senior author Professor Philip Munday, of the ARC Centre of Excellence for Coral Reef Studies (CoralCoE) at James Cook University.

"For example, carbon dioxide levels on coral reefs are often much lower during the day than they are at night."

"Our data suggests that these natural daily changes in water chemistry are enough to provide fish with a recovery period, reducing their sensitivity to higher carbon dioxide levels," said Michael D. Jarrold, lead author of the study and PhD student at James Cook University.

The study published today in Scientific Reports, utilised state-of-the-art facilities at James Cook University and at the Australian Institute of Marine Science's National Sea Simulator (SeaSim) to mimic the natural conditions of a coral reef environment.

Read more at: https://phys.org/news/2017-08-reef-fish-high-co2-world.html#jCp