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The study is one of the first to look at the impact of ocean acidification on marine invertebrates that don’t have a large calcified skeleton or external shell, and challenges current assumptions about the potential impact of climate change on marine species.

The findings were published online this week in the Proceedings of the National Academy of Sciences.

In the lab, UBC researchers led by Rebecca Gooding manipulated water temperatures and CO₂ levels in sea water tanks containing juvenile Purple Ochre Sea Stars (Pisaster ochraceus), a species found along much of North America’s Pacific Coast.

An increase in temperature of just three degrees and doubling of CO₂ concentrations enabled the sea stars to grow almost twice as fast as they normally would over a period of ten weeks.

“This means the sea stars could potentially reach adulthood in about half the time it would typically take–and consume more mussels, their main diet, at much higher rates,” says Gooding, a PhD student in the Department of Zoology working under the supervision of UBC Assistant Professor Christopher Harley.

At the end of the period, sea stars reared in warmer, more acidic waters weighed 17 grams, compared to control sea stars that weighed an average of only 11 grams. In contrast, existing studies suggest that an increase in temperature and CO₂ levels hinder growth in most species studied so far—usually more calcified species...