Scientists “thrilled”: fish cope with acidification if tanks mimic normal large daily CO2 swings

The real story here is that past scares claiming that ocean acidification would create reckless fish were most likely an artefact of an inadequate experiment. There are big swings of CO2 and pH in shallow water environments, and the normal day-night cycle turns out to be good for fish. Putting them in a laboratory tank without these daily changes may create fish that behave badly. So ocean acidification is not only natural, but a good and necessary thing.

New hope for reef fish living in a high CO2 world

Chemical changes in the ocean, as a result of climate 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 […]