Snails confound expectations of life in acidic waters: New Zealand study

Survival in the world's acidifying oceans, a result of climate change, might depend on strange circumstances for some species, according to New Zealand research out Wednesday.

Flatworm-infected sea snails survived better in more acidified seawater than non-infected ones, researchers at the University of Otago were surprised to find.

They conducted a 90-day experiment that examined death rates of the New Zealand mud snail in seawater at current pH levels and in conditions predicted for the years 2100 and 2300.

They found that survival rates of infected snails showed little change between each condition, uninfected snails died at higher rates in the acidified seawater.

The likely explanation was that compared to uninfected sea snails, infected ones had more energy available to deal with the increased metabolic costs incurred in acidified seawater, study main author Dr Colin MacLeod said in a statement.

"Snails infected by flatworms are invariably 'castrated' by these parasites, meaning that they no longer expend energy on reproductive activities. This leaves them with more energy to maintain their acid-base balance and shell integrity in the acidified conditions," MacLeod said.

The findings were likely to apply to a range of other marine organisms.

"Our study strongly supports the growing consensus that parasitic infection must be carefully taken into account in attempts to accurately assess the impact of ocean acidification on ecologically and commercially important marine species," he said. Endit