Source: ABC 
January 23, 2012
"TONY EASTLEY: An international team of scientists says rising carbon dioxide concentrations in sea water can cause significant damage to the brains of fish.
More than two billion tonnes of carbon dioxide emissions are dissolved into the world's oceans each year causing changes in the chemical makeup of the water.
Professor Philip Munday told AM's Bronwyn Herbert that they found marked changes in the behaviour and sensory ability of young coral fish.
PHILIP MUNDAY: Higher CO2 levels in the ocean, the sorts of levels that we might see by the end of this century if we continue on our current carbon dioxide emission trajectory. Those sort of CO2 levels they actually influence the behaviour of baby coral reef fish. We found that the things that can be altered are behaviours such as their ability to smell predators, to turn left or right, to hear the sounds of reefs. These things are altered.
We've known this for a little while but we haven't really understood what the common mechanism is that has linked all these sorts of diverse changes in behaviour and sensory ability and in our new work what we've found is that it is interference with a certain neurotransmitter in the brain called the GABA(A) receptor that is actually responsible for all these sorts of diverse effects on behaviour."
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