Snail shells are surprise weather time capsules
The shell of a Biggenden Banded Snail at Coalstoun Lakes National Park.
(Photo credit: The University of Queensland )
Key points
- Scientists have mapped the composition of a snail shell to weather records.
- Analysis showed rapid growth after extreme rainfall events.
- It means ancient shells could be used to reconstruct the paths of past cyclones.
Snails carry weather records on their backs that could be used to map prehistoric cyclones, a University of Queensland study has shown.
A project led by School of the Environment researchers examined the rings on the shell of a Biggenden Banded Snail (Figuladra bayensis) collected from Coalstoun Lakes National Park in South East Queensland, linking its bands to weather records.
Dr Nicholas Patton said tiny samples of the shell taken at millimetre intervals revealed the age of the snail, when it lived and the weather during its lifetime.
“We used high resolution radiocarbon dating to determine the age of the growth bands in the shell,” Dr Patton said.
“It contained elevated levels of radiocarbon from the nuclear tests in Australia in the 1960s, meaning we could date the growth bands and reveal the snail had lived for about 4.5 years.
“Analysing the oxygen and carbon stable isotopes of the different bands revealed insights into the rainfall the snail experienced.
“What we saw was the shell did not grow continuously during the snail’s life; there were periods of rapid growth separated by periods of little or no growth.”
Honorary Professor Jamie Shulmeister said the team initially expected the rapid growth phases to correspond to years with heavier rainfall making more food available for the snail.
“But the results showed the snail was responding to extreme rainfall events rather than annual wetness,” Honorary Professor Shulmeister said.
“Because we knew when the snail lived, the growth spurts could be linked to periods immediately following cyclones in 2015 and 2017.
“Severe Tropical Cyclone Marcia and Tropical Cyclone Debbie both caused extreme rainfall within the Coalstoun Lakes National Park.
“It shows that snail shells could be used to map extreme weather events for periods before modern meteorological records.
“It was surprising and quite exciting that the humble snail could be a tool to reconstruct the paths of past cyclones even in prehistoric times.”
The researchers' next step is to test the approach.
“If we are able to find shells within different layers of sediment deposits, we can combine the individual shell records together to extend this information further back in time,” Dr Patton said.
Read the research published in The Holocene.
Collaboration and acknowledgements
The research was completed with Professor Melanie Leng of the British Geological Survey and University of Nottingham, and Dr Quan Hua from the Australian Nuclear Science and Technology Organisation (ANSTO).
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