Daily-weekly scale precipitation events in the monsoon marginal zone recorded by high-resolution 18O of land snail shells

Weather-scale precipitation have a significant impact on ecosystems and human activities. Reconstructing weather-scale precipitation events is critical to improving our understanding of precipitation event mechanisms. Currently, the snail shells ultra-high resolution 18O records obtained by secondary ion mass spectroscopy (SIMS) is the main methods of reconstruction the terrestrial weather-scale precipitation events. However, research in this field is limited due to the rarity and costliness of SIMS instrumentation, as well as the complexity of sample preparation. In this study, we collected three modern land snails (Cathaica fasciola) from the Shizuishan area in Northwest China in June, September, and December 2021. The shells of these snails were sampled continuously with a spatial resolution of ~700mand tested using gas-source mass spectrometry(GSMS) to obtain high-resolution 18Orecords. The results showed that the 18Oof snails shell(18Oshell) of different snails grown at the same time period were well reproducible.Weobtained the growth rate of Cathaica fasciola is546m/day from June to September.This growth rateis obviouslyfaster thanXingyang(181m/day from June to September) and Xi'an(56m/day from April to September). The observed disparity in growth rates may be attributed to the snail survival strategy changes, which appear to be more efficient in water usage in the monsoon margin zone. More importantly, the 18Oshellexhibited sensitivity to precipitation, as evidenced by threenegative fluctuations in 18Oshellrecord that corresponded to three precipitation events during the period. These findings indicate that 18Oshellrecordsobtained byGSMS couldeffectively capture weather-scale precipitation information in the monsoon margin region. GSMSis widely used, less costly for testing, and relatively simple for sample preparation. This greatly improves thefeasibility and applicability in reconstructweather-scale precipitation events under different climatic conditions using 18Oshellrecord, and deepens our understanding of the mechanisms such events.Meanwhile, this finding holds significance in unraveling the intricate nature of weather-scale precipitation events.