Australasian Science: Australia's authority on science since 1938

Acid Trips Cone Snails

Deadly cone snails are too clumsy to catch their prey when exposed to the levels of ocean acidification expected due to climate change, according to research published in Biology Letters (http://tinyurl.com/hf3npjh).

The study reveals the impact that rising carbon dioxide levels could have on the ocean food chain. “We found the carbon dioxide made the cone snails hyperactive,” says lead author Dr Sue-Ann Watson of the ARC Centre of Excellence for Coral Reef Studies at James Cook University. “But despite moving three times faster than normal they caught fewer prey. They meandered around instead of moving by stealth and sneaking up on their prey.”

Cone snails typically hide in the sand to surprise their enemy. They harpoon their prey using a powerful venom that can also be fatal to humans.

The scientists took cone snails from around Lizard Island, on the Great Barrier Reef, and put them into tanks with a popular cone snail delicacy – jumping snails – but only 10% of the cone snails under the influence of elevated CO2 managed to catch their dinner compared with 60% of those kept in tanks under normal conditions.

Ocean acidification occurs when the ocean absorbs carbon dioxide from the atmosphere, resulting in chemical changes as the pH of the water decreases. “We already know that ocean acidification will weaken snails’ shells, and this new research shows it can also affect their energy levels by increasing activity while at the same time decreasing their food intake,” said Prof Philip Munday.

Previous work by Watson has shown that the behaviour of the cone snail’s prey, such as jumping snails, is altered by elevated CO2 levels. This new study shows that predator behaviour is affected as well.

“As the behaviour of species change under these conditions, so too can the relationship between predator and prey,” Watson said. “The results of this study could have implications for food chains beyond cone snails and their prey.

“Marine snails and other molluscs are important for the ocean food chain, and are also resources for humans. If their behaviour changes there could be a flow-on effect in the food chain. These changes could potentially affect commercially important seafood species,” Watson said.