In research published in the Proceedings of the Royal Society B, the scientists reared larval abalone and sea urchins in water that mimicked present ocean conditions and compared them with young raised in conditions predicted to prevail in 100 years’ time.

After 21 hours, the abalone larvae raised in the control conditions had well-developed shells, while those reared under more acidic conditions were either dead or severely abnormal. Meanwhile, a 2°C increase in temperature had a negative effect on development and only 20 per cent of young raised in water
4°C warmer than today survived.

A slight increase in temperature actually favoured the larval sea urchins, but a lower pH reduced the number of spines they grew. When the conditions were combined, it resulted in abnormal development in 80 per cent of young.

According to the lead author of the research, Maria Byrne of the University of Sydney, Sydney Harbour could experience conditions similar to those in the experiments as early as 2070. ‘We are warming appreciably faster than other parts of the world because we have the East Australian Current, which is bringing warm water all the way down the coast to Tasmania,’ she said.

April 2011