Using Lipid Biomarkers and their Isotopic Composition to reconstruct the Late Pleistocene Paleoclimate of the Amazon Basin

This thesis deals with the reconstruction of the late Pleistocene climate and vegetation history of the Amazon basin and is made up of three manuscripts: In the first manuscript biomarker based paleosalinity proxies are tested. It is shown that the stable hydrogen isotope composition of palmitic acid reflects the salinity conditions in the Amazon Outflow Plume, while the stable hydrogen isotope composition of alkenones is influenced by factors other than salinity. The second manuscript deals with the transport of long-chain n-alkanes in the Amazon River and its main tributaries. It is demonstrated that long-chain n-alkanes mainly originate from the lowland basin, contrasting the dominant inorganic sediment source in the Andes. The third manuscript deals with the application of plant wax proxies in a marine sediment core covering the late Pleistocene. It is shown that forest vegetation persisted through drier conditions during the last glacial maximum, while minor savanna expansion occurred during Heinrich Stadials

On the stratigraphic integrity of leaf-wax biomarkers in loess paleosols

Paleoenvironmental and paleoclimate reconstructions based on molecular proxies, such as those derived from leaf-wax biomarkers, in loess-paleosol sequences represent a promising line of investigation in Quaternary research. The main premise of such reconstructions is the synsedimentary deposition of biomarkers and dust, which has become a debated subject in recent years. This study uses two independent approaches to test the stratigraphic integrity of leaf-wax biomarkers: (i) long-chain n-alkanes and fatty acids are quantified in two sediment-depth profiles in glacial till on the Swiss Plateau, consisting of a Holocene topsoil and the underlying B and C horizons. Since glacial sediments are initially very poor in organic matter, significant amounts of leaf-wax biomarkers in the B and C horizons of those profiles would reflect postsedimentary root-derived or microbial contributions. (ii) Compound-specific radiocarbon measurements are conducted on n-alkanes and n-alkanoic (fatty) acids from several depth intervals in the loess section "Crvenka", Serbia, and the results are compared to independent estimates of sediment age. <br><br> We find extremely low concentrations of plant-wax n-alkanes and fatty acids in the B and C horizons below the topsoils in the sediment profiles. Moreover, compound-specific radiocarbon analysis yields plant-wax ¹⁴C ages that agree well with published luminescence ages and stratigraphy of the Serbian loess deposit. Both approaches confirm that postsedimentary, root-derived or microbial contributions are negligible in the two investigated systems. The good agreement between the ages of odd and even homologues also indicates that reworking and incorporation of fossil leaf waxes is not particularly relevant either

Hierarchical Equations of Motion Approach to Quantum Thermodynamics

We present a theoretical framework to investigate quantum thermodynamic processes under non-Markovian system-bath interactions on the basis of the hierarchical equations of motion (HEOM) approach, which is convenient to carry out numerically "exact" calculations. This formalism is valuable because it can be used to treat not only strong system-bath coupling but also system-bath correlation or entanglement, which will be essential to characterize the heat transport between the system and quantum heat baths. Using this formalism, we demonstrated an importance of the thermodynamic effect from the tri-partite correlations (TPC) for a two-level heat transfer model and a three-level autonomous heat engine model under the conditions that the conventional quantum master equation approaches are failed. Our numerical calculations show that TPC contributions, which distinguish the heat current from the energy current, have to be take into account to satisfy the thermodynamic laws.Comment: 9 pages, 4 figures. As a chapter of: F. Binder, L. A. Correa, C. Gogolin, J. Anders, and G. Adesso (eds.), "Thermodynamics in the quantum regime - Recent Progress and Outlook", (Springer International Publishing

Die Rekonstruktion der spätpleistozänen Paleoklimageschichte des Amazons Beckens mittels Lipid Biomarkern und deren Isotopenzusammensetzung

This thesis deals with the reconstruction of the late Pleistocene climate and vegetation history of the Amazon basin and is made up of three manuscripts: In the first manuscript biomarker based paleosalinity proxies are tested. It is shown that the stable hydrogen isotope composition of palmitic acid reflects the salinity conditions in the Amazon Outflow Plume, while the stable hydrogen isotope composition of alkenones is influenced by factors other than salinity. The second manuscript deals with the transport of long-chain n-alkanes in the Amazon River and its main tributaries. It is demonstrated that long-chain n-alkanes mainly originate from the lowland basin, contrasting the dominant inorganic sediment source in the Andes. The third manuscript deals with the application of plant wax proxies in a marine sediment core covering the late Pleistocene. It is shown that forest vegetation persisted through drier conditions during the last glacial maximum, while minor savanna expansion occurred during Heinrich Stadials

Data for: Modern and late Pleistocene particulate organic carbon transport by the Amazon River: Insights from long-chain alkyl diols

Long-chain alkyl diol data, GDGT data and XRF data from suspended sediment samples from the Amazon River, surface sediment samples from the tropical Atlantic, and sediment samples from core GeoB16224-1

Data for: Modern and late Pleistocene particulate organic carbon transport by the Amazon River: Insights from long-chain alkyl diols

Long-chain alkyl diol data, GDGT data and XRF data from suspended sediment samples from the Amazon River, surface sediment samples from the tropical Atlantic, and sediment samples from core GeoB16224-1.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV