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Fish Fail to Adapt to Rising CO2 Levels: Study

By Oliver Milman, The Guardian


Rising CO2 levels result in ocean acidification which makes it hard for crustaceans to form shells, while corals are more prone to bleaching.
Credit: J.P. Lawrence/flickr


Spiny damselfish were kept in water with different CO2 levels for several months. One level was consistent with the world taking rapid action to cut carbon emissions, while the other was a “business as usual” scenario, in which the current trend in rising emissions would equate to a 3°C (5.4°F) warming of the oceans by the end of the century.


This suggests that fish will take at least several generations to cope with the changed environment, with no guarantee they will ever do so, meaning several species could be at risk of collapsing due to climate change.


Previous studies by the center have found that rising CO2 levels in the oceans directly alters neuron transmitters in fish brains, modifying their behavior. Their sense of smell is hindered, as well as their wariness, meaning more are picked off by predators.

More than 90 percent of the excess CO2 in the atmosphere, primarily caused by the burning of fossil fuels, is soaked up by the oceans.

When CO2 is dissolved in water it causes ocean acidification, which slightly lowers the pH of the water and changes its chemistry. Crustaceans can find it hard to form shells in highly acidic water, while corals are more prone to bleaching.





Reprinted with permission by The Guardian



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