Deciphering the hydroclimatic significance of dripwater δ13CDIC variations in monsoonal China based on modern cave monitoring

Hydrogeochemical responses of cave drip water to the local climate in the Liangfeng Cave, Southwest China

“…Hydrological dynamics is one of the important processes governing the water-CO 2 -rock interactions that was affected by the amount of precipitation during an ENSO event. Many studies have revealed that enhanced meteoric recharge could dissolve and deliver constant and larger amount of CO 2 from soil into epikarst, causing carbonate dissolution and thus higher EC and Ca 2þ and HCO À 3 values (Baker et al 2000;Tooth & Fairchild 2003;Zeng et al 2015;Yin et al 2021). Therefore, the hydrogeochemistry at these sites was controlled by the amount of precipitation during this time.…”

“…However, the increasing number of monitoring studies published in recent years indicates that the intensity of water-rock reaction, fresh-old water mixing and degassing (Zeng et al 2015;Yin et al 2021), dilution effect, the piston effect, prior calcite precipitation (Tooth & Fairchild 2003), the thickness of bedrock and the retention time of seeping water (Baker & Brunsdon 2003) are the principal factors in epikarst that interfere with the hydrogeochemical variations of drip waters. Moreover, different runoff paths lead to different response sensitivities at different drip water sites (Faimon et al 2016).…”

Strong coupling of the East Asian summer monsoon and hydroclimate footprints during 53–47 ka

“…S1), as aforementioned, although the limitations of resolution and age deviation exist among them. Furthermore, the newly modern monitoring results show that the cave drip water δ 13 CDIC is definitely a potential proxy for reflecting regional monsoon rainfall on the inter-annual to decadal scales (Li et al, 2021;Yin et al, 2021). Therefore, within subtropical or moderate monsoon regime, advanced bio-productivity (e.g., vegetation and microbial activity) associated with warm and humid climates, will produce high soil CO2 partial pressure (pCO2) and lead to lower δ 13 C values in cave feeding water.…”

“…They argued that the δ 13 C reflects rainfall in northern China with reliability, and further proposed an insight into the climatic significance of stalagmite δ 18 O by the use of δ 13 C record. Moreover, modern cave observations show the δ 13 CDIC and trace elemental ratios in cave drip solution (or stalagmite formation) are clearly responsive to the local hydroclimatic variations, especially during the flood and drought events (Chen and Li, 2018;Yin et al, 2021). Therefore, they can definitely be used as the potential indicators for regional monsoon rainfall changes on the inter-annual to decadal scales (Li et al, 2021).…”