How Snail Shells Could Be Used to Map Prehistoric Cyclones

The hard shells around snails protect them against predators, act as cover for rain and sunshine, and lock in moisture. They’re also able to serve as meteorological time capsules, a new study shows. Researchers examined a shell from a snail that died in August 2018, in the Coalstoun Lakes National Park in South East Queensland, and identified it as a Biggenden Banded Snail (Figuladra bayensis).

Then, using radiocarbon dating and oxygen and carbon isotope analysis, they determined that the snail had lived for four-and-a-half years. Its shell also showed signs of rapid growth spurts, together with periods of slow growth, or no growth at all. Read more: “How Snails Cross Vast Oceans” The normal expectation would be that these spurts correlated to wetter seasons, when there was more food around for the snail to languidly snack on, but the researchers discovered that the real story was more dramatic.

As Marcia and Debbie left the forest floors saturated, snails like the one studied were able to drink deep, imbibing the ultralight oxygen that characterizes the water in fast-moving storms. Shells, it turns out, work a little like tree rings: They lock in some of the environmental conditions of the time, so scientists can come back later and read the signs etched into the calcium carbonate. This is just a single shell, in a single location, but if the same analysis can be applied to others, we’ve got a new way of identifying the times and places of storms back through the centuries.

In fact, shells could take us much further back in history than conventional meteorological records. Matching older samples would be harder and less precise, but they could answer questions about the frequency or intensity of cyclones and establish the climate records of areas over time. Subscribe to our free newsletter.