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oa Mobilization of pre-aged organic carbon in the Nile-River watershed linked to hydologic changes during the past 20ka
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 30th International Meeting on Organic Geochemistry (IMOG 2021), Sep 2021, Volume 2021, p.1 - 2
Abstract
This project seeks to detect perturbations in the carbon cycle in large (sub-) tropical watersheds during the last deglaciation and the Holocene and to understand their climatic controls. It is generally assumed that in tropical regions, the fluvially exported organic matter is rather young due to rapid carbon turnover and often dense vegetation in the catchments. However, evidence for mobilization of pre-aged organic carbon in tropical regions has recently been obtained from the Congo-River catchment. Hydrology is suggested as a major control on the mobilization of pre-aged organic matter mediating the carbon storage in river-associated wetlands. Yet, the link between hydrology and the mobilization of old carbon in tropical regions as well as the associated climate feedbacks remain poorly constrained. Here, we investigate whether hydrologic changes affected the re-mobilization of pre-aged terrigenous organic carbon in the Nile-River watershed during the past 20ka. We present biomarker data from a sediment core recovered from the Mediterranean. Applying compound-specific radiocarbon analysis on terrigenous biomarkers we identify intervals of intensified mobilization of pre-aged terrigenous organic matter. We combine these data with compound-specific stable hydrogen isotope compositions of the same compounds to reconstruct past hydrologic conditions and their effects on mobilization of pre-aged organic matter.
