A lot of what allows us to understand Mars comes from research done trying to understand our planet Earth. And it’s not just Mars. Ocean researchers and Jupiter atmospheric scientists collaborate to try and figure out things like eddies that appear both in our oceans and Jupiter’s skies.

Where comparative planetology currently breaks down is where we here on Earth turn to lifeforms to help us understand our planet’s past. Tree rings for example: great for Earth, non-existent for Mars. And snails. Even the humble snail plays a role in understanding our world’s geophysical past.

The geologic record is plagued with mass extinctions scientists have to try and explain. In several cases, researchers looking at rocks had blamed ocean acidification events, but now other researchers have said, to paraphrase, But the snails don’t agree.

Here is the background according to a release related to this study: The world’s deadliest mass extinction wiped out about 90% of living species about 252 million years ago at the end of [the] Permian Period. The extinction was triggered by huge volcanic eruptions in present-day Siberia, which released large amounts of carbon dioxide into the atmosphere in a relatively short amount of time, causing rapid global warming.

And folks thought that carbon dioxide would acidify the oceans, but the snails don’t agree.

Researchers looking at 2,300 fossil shells from marine snails under microscopes didn’t find evidence, such as patched holes or damaged shells, that would indicate they lived in an acidic environment. So yeah, that theory is out the window. New theory time.

This work is published in Scientific Reports and led by William Foster with second author Jaime Hirtze who, I’d like to note, started this work as an undergraduate and just completed their master’s, 2,300 fossilized snail shells later.

The snails don’t lie.

More Information

UTA press release

“Bioindicators of severe ocean acidification are absent from the end-Permian mass extinction,” William J. Foster et al., 2022 January 24, Scientific Reports