In karst landscapes, past climate can be reconstructed using cave archives such as speleothems and flowstone. These form when rainwater reacts with limestone: carbonic acid develops and leads to calcite precipitation. Because they grow slowly and remain relatively stable, they preserve a continuous record of regional climate, for example on the Swabian Alb.

By analyzing stable oxygen isotopes (δ¹⁷O and δ¹⁸O) and hydrogen isotopes (δ²H) in the water associated with these deposits, we can investigate climate-related processes within the hydrological cycle across both space and time. Changes in δ¹⁷O, δ¹⁸O, and δ²H are strongly controlled by precipitation amount and temperature, as well as by interactions between the atmosphere, prevailing weather patterns, and the properties of the karst host rock.

Our work aims to better understand key climatic parameters on the Swabian Alb — above and below ground — and to clarify how they drive hydrological processes in karst systems.

In 2022 the weather station on the institute roof in Tübingen was established, and we began looking for promising sites for monitoring weather and karst environments on the Swabian Alb. Since 2023, we have implemented a high-resolution monitoring program at Bärenhöhle, Nebelhöhle, Schertelshöhle, Falkensteiner Höhle, and Hohle Fels caves. At these sites, dataloggers continuously record temperature, relative humidity, drip water dynamics, and allow us to collect “modern speleothems” (precipitated calcite) that form on the watch glass at the top of the dataloggers (see picture below).

In addition, we regularly collect cave drip water and measure CO₂ concentration at different locations within each cave. In parallel, rainfall amount and isotopic composition in rainwater and cave spring water in the surrounding region are measured using microclimate stations and water collectors at Tübingen, Blaubeuren, Westerheim, Grabenstetten, and Goldloch (Lenningen). This integrated setup enables us to track how surface climate signals are transferred into the subsurface cave environments, providing a robust process-based framework for understanding signal transfer and preservation.

Building on nearly three years of continuous data, we further aim to enhance this network with new, and mobile, weather stations across the Swabian Alb.