Sedimentary n-alkanes, their hydrogen isotopes, GDGTs and d15N as well as δ¹³Corg of lake Nam Co, Tibet

In this study, we examined the interplay between the Indian Ocean Summer Monsoon (IOSM) and the Westerlies at lake Nam Co, southern Tibet to understand the climatic effects on the ecosystem. Different organic geochemical proxies (n-alkanes, glycerol dialkyl glycerol tetraethers, dD, d13Corg, d15N) are applied to reconstruct the environmental and hydrological changes on one of the longest available paleorecords at the Tibetan Plateau.

Based on our paleohydrological dD proxies, the aquatic signal lags the terrestrial one due to specific ecological thresholds, which, in addition to climatic changes, can influence aquatic organisms. The aquatic organisms' response strongly depends on temperature and associated lake size, as well as pH and nutrient availability. Because the terrestrial vegetation reacts faster and more sensitively to changes in the monsoonal and climatic system, the dD of n-C29 and the reconstructed inflow water signal represent an appropriate IOSM proxy.