Snail shells reveal past rainfall patterns

The chemical composition of snail shells is allowing scientists to reconstruct records of past storms. This technique promises to be useful for understanding rainfall patterns in various regions of the world, including areas where historical records are scarce. A recent study focused on a Biggenden banded snail, found in Coalstoun Lakes National Park, Australia. This snail lived from 2013 to 2018, during which time researchers were able to analyze changes in its shell to identify intense rainfall events, such as those caused by tropical cyclones ^1,2.

Method of analysis

Researchers used radiocarbon dating and oxygen isotopes to determine when different parts of the shell were formed. These techniques allowed them to associate variations in the shell's composition with specific climatic events, such as heavy rains. The snail's shell is made of aragonite, a crystallized form of calcium carbonate, which records environmental information over time ².

The application of this technique can be expanded to other land snails in different parts of the world. This would allow the reconstruction of rainfall patterns in regions where historical records are limited, such as parts of South America and deserts in the southeastern United States. The analysis of snail shells can provide a detailed view of climatic conditions over several years before the animal's death ².

Coalstoun Lakes National Park, where the study was conducted, is an ideal location for this type of research due to its geography. The park is formed by lakes that fill and dry periodically, acting as a natural trap for rain. This characteristic facilitates the analysis of climate records preserved in the shells of snails ².