CEST2025

Reconstructing past hydrological variability provides valuable context for understanding the impacts of climate change in regions like Patagonia, where human influence has been minimal. This study analyzes sedimentary and biogeochemical proxies, including δ2H values in leaf waxes, to explore hydrological changes over the last millennium in two northern Patagonian lakes with distinct precipitation regimes: Lake Oscuro (high precipitation) and Lake Tranquilo (moderate precipitation). Results reveal significant differences in organic content and proxy behavior, driven by varying hydrological conditions. Lake Oscuro, influenced by the Exploradores glacier, shows abrupt sedimentological shifts tied to glacier lake outburst floods and higher precipitation-driven transport of vascular plant material. The δ2H values differ notably between the lakes, reflecting regional hydrological dynamics and providing insights into precipitation variability during periods like the Little Ice Age and the Medieval Climatic Anomaly. These findings highlight the sensitivity of Patagonian ecosystems to hydrological shifts, emphasizing the importance of δ2H in leaf waxes as a tool for detecting changes in the water cycle. By shedding light on natural climatic variability, this research contributes to understanding how ongoing climate change could further disrupt hydrological processes and ecosystem stability in precipitation-sensitive regions.