| Autor: |
Gaviria-Lugo, Nestor, Läuchli, Charlotte, Wittmann, Hella, Bernhard, Anne, Frings, Patrick, Mohtadi, Mahyar, Rach, Oliver, Sachse, Dirk |
| Předmět: |
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| Zdroj: |
Biogeosciences Discussions; 5/4/2023, p1-34, 34p |
| Abstrakt: |
The hydrogen isotope composition of leaf wax biomarkers (δ²Hwax) is a valuable tool for reconstructing continental paleohydrology, as it serves as a proxy for the hydrogen isotope composition of precipitation (δ²Hpre). To yield robust palaeohydrological reconstructions using δ²Hwax in marine archives, it is necessary to examine the impacts of regional climate on δ²Hwax and assess the similarity between marine sedimentary δ²Hwax and the source of continental δ²Hwax. Here, we examined an aridity gradient from hyperarid to humid along the Chilean coast. We sampled sediments at the outlets of rivers draining into the Pacific, soils within catchments and marine surface sediments adjacent to the outlets of the studied rivers and analyzed the relationship between climatic variables and δ²Hwax values. We find that apparent fractionation between leaf waxes and source water is relatively constant in humid/semiarid regions (average: -121 ‰). However, it becomes less negative in hyperarid regions (average: -86 ‰) as a result of evapotranspirative processes affecting soil and leaf water 2H enrichment. We also observed that along strong aridity gradients, the ²H enrichment of δ²Hwax follows a non-linear relationship with water content and water flux variables, driven by strong soil evaporation and plant transpiration. Furthermore, our results indicated that δ²Hwax values in marine surface sediments largely reflect δ²Hwax values from the continent, confirming the robustness of marine δ²Hwax records for paleohydrological reconstructions along the Chilean margin. These findings also highlight the importance of considering the effects of hyperaridity in the interpretation of δ²Hwax values and pave the way for more quantitative paleohydrological reconstructions using δ²Hwax. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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