Organic Geochemistry

• Temperature adaptation of two Gram-negative bacterial strains isolated from Alpine lakes. • Non-linear response to temperature, relying mainly on non-hydroxy fatty acids. • The strains exhibit slight differences in temperature adaptation. 3-hydroxy fatty acids (3-OH FAs) produced by Gram-negative bacteria were recently proposed as promising temperature proxies. Nevertheless, the lipid adaptatio…

• Enhanced methanotrophic activity and sediment processing in summer in the emerging lake. • Lake morphology strongly influenced DOM dynamics in the water column during summer. • Mature lake had highest aromatic DOM and chromophoric DOM in summer, with more recalcitrant soil. • Winter induced shifts toward condensed DOM structures and stimulated Fe redissolution. As Arctic and Subarctic regions w…

• Reliable isomeric assignments for monosaccharide anhydrides using LC-MS/MS. • Robust dual-platform LC-MS/MS and GC–MS analytical workflow. • Column chemistry and isomer-specific MS/MS transitions govern MA identification. • Derivatized and underivatized monosaccharide anhydrides exhibit distinct stability. Monosaccharide anhydrides (MAs), levoglucosan (LVG), mannosan (MAN), and galactosan (GAN)…

• Oils in the Xihu Sag have diverse sources with both terrigenous and marine organic matter. • Biomarker and carbon isotope signatures elucidated multiple source kitchens in the Xihu Sag. • Ternary diagrams of phenanthrenes provide new tools for oil-source correlation in the study area. The Xihu Sag is a significant petroleum-bearing area in the East China Sea. Its petroleum exhibits unclear orig…

• We compared base hydrolysis and pyrolysis to trace fossil root-derived OM. • Both approaches revealed the presence of suberin monomers in calcified roots. • Pyrolysis failed to detect suberin monomers in rhizosphere and root-free sediments. • In OM-poor and fossil systems, only base hydrolysis enables tracing of root remains. Hydrolyzable lipids including suberin-derived monomers have been used…

• The initial chemical composition has an effect on Raman spectra in charcoals. • This composition effect disappears in charcoals formed above 600 °C. • Raman spectra may reveal differences in the intensities of archaeological fires. Charcoal is a key archaeological artefact, providing evidence of human presence, enabling site dating and delivering information about ancient practices notably thro…

• O-PTIR and AFM-IR techniques achieve micrometric and nanometric lateral resolutions. • An extremely flat surface is necessary for accurate O-PTIR and AFM-IR analyses. • Only AFM-IR records fossil spectra with no to little contribution from amber. • These techniques can resolve micrometric chemical heterogeneity in ancient material. IR spectroscopy is a powerful tool for characterising the chemi…

• Mahu Sag source rocks are classified into P 1 f (saline lacustrine) and P 2 w (freshwater to brackish lacustrine). • δ 13 C and δ 2 H can effectively classify oil type and determine oil sources. • The crude oils are classified into three groups: P 1 f -derived, P 2 w -derived, and mixed oils. • Depositional environment is the primary factor controlling the δ 2 H composition of n -alkanes in oil…