New evidence shows that rising CO2 levels may actually affect reef fishes’ entire central nervous systems. CO2 concentrations are predicted to hit levels between 700 and 900 before the end of the century according to the Australian Research Council Centre of Excellence for Coral Reef Studies and James Cook University.

”It is now pretty clear that they sustain significant disruption to their central nervous system, which is likely to impair their chances of survival,” Professor Philip Munday said yesterday. ”We’ve found that elevated carbon dioxide in the oceans can directly interfere with fish neurotransmitter functions, which poses a direct and previously unknown threat to sea life.”

Research included examining how baby clownfish coped with high CO2 water, and while predators had some trouble with it, the clownfish had much more. ”They found it harder to locate a reef to settle on or detect the warning smell of a predator fish,” Professor Munday said. Researchers found that their hearing and smell were greatly effected, and they even started losing their natural instinct to turn left or right.

”All this led us to suspect it wasn’t simply damage to their individual senses that was going on but rather that higher levels of CO2 were affecting their whole central nervous system.”

These results led the team to believe that the high CO2 levels were effecting the fishes whole nervous systems’ by stimulating receptors in the brain’s GABA-A cells. This reverses  their function causes some signals to become over excited.

”We’ve now established it isn’t simply the acidification of the oceans that is causing disruption, as is the case with shellfish and plankton with chalky skeletons. But the CO2 itself is damaging the fishes’ central nervous systems.”

Via: The Age