Previous experiments have given an unduly optimistic view of the impact of acidifying oceans on plankton; it turns out that the methods used may have biased their results.

"Plankton often grow in clumps or aggregates," says Professor Kevin Flynn of Swansea University, lead author of the study. "But the way they are handled tends to break these clumps up. When a scientists starts working on a plankton sample in the lab, the first thing they do is give it a good shake."

How acidity affects microbes depends greatly on the size of the aggregate they're in, so studying plankton whose intricate communities have been disrupted doesn't give an accurate picture of the conditions they will face in the wild.

To correct this distortion, UK and Australian researchers used computer simulations to examine the chemical environment immediately around the bodies of plankton in varying conditions. They found that if predictions of general ocean acidification come true, many kinds of plankton will face much more acidic conditions, and more widely varying conditions over each day, than previously realized – conditions far beyond anything seen in recent history. The results are likely to be stunted growth, or even death.