Gassed snails can’t jump

Exposure to extra carbon dioxide slows or stops the animals' defense tactics

Sea snails, such as this one, use footlike limbs to jump out of the way of attacking predators. But high levels of carbon dioxide can slow or stifle the snails' escape tactic.

By Ashley Yeager

November 12, 2013 at 8:15 pm

Sea snails use footlike limbs to jump away from predators and avoid being eaten. But when exposed to high levels of carbon dioxide, some snails react slowly and others don’t jump at all.

Researchers put Gibberulus gibbosus snails in lab tanks of seawater infused with either levels of CO₂currently found in the ocean or elevated levels projected for the end of the century. When tipped off that a predator was near, half of the snails exposed to increased CO₂ levels did not jump. The gassed snails that did jump were slower to react and did not use the leaps to move away from predators, the team reports November 12 in the Proceedings of the Royal Society B.

Higher CO₂ levels interfere with the snails’ nervous systems and impair the animals’ decision-making, the scientists conclude. The altered behavior could affect the dynamics of ocean ecosystems, shellfish industries and food security in the future, they say.