Application of Lipid Biomarkers and Compound-Specific Isotopes to Reconstruct Paleoenvironmental Changes in Terrestrial and Marine Sedimentary Records

The number of studies using lipid biomarkers has rapidly increased during the last two decades. Employed in these studies are a wide range of biomarkers from diverse biological sources and environmental settings, demonstrating the extent to which lipid biomarkers can reveal important information on past environmental conditions. Given the source-specificity of biomarkers, these proxies can offer multiple unique perspectives on environmental change depending on the growth habit of the source organism, with the isotopic composition of lipid biomarkers often strongly related to distinct biogeochemical processes and organic matter sources. However, the interpretation of biomarker data can be limited by the poor constraint of controlling biologic parameters (e.g., unknown producers, mixed inputs, the effect of growth rate and growth phase, species-specific fractionation) and/or abiotic parameters (e.g., competing environmental gradients).

With this Research Topic, we aim to highlight recent advances in the use of lipid biomarker-based proxies, including the use of biomarker distributions and compound-specific isotopes (including but not limited to carbon, hydrogen, oxygen, and nitrogen) to reconstruct paleoenvironmental conditions and constrain the provenance of organic matter. We also encourage work using novel applications or from regions where prior work is limited or clear issues are observed in otherwise well-calibrated biomarkers.

This Research Topic welcomes contributions focused on specific aspects of lipid biomarker proxy systems such as:
• Integrating signals from multiple lipid-biomarkers for reconstructing paleoenvironmental change in marine or lacustrine settings;
• The methane cycle, including modern or sedimentary lipids produced by methanogen and methanotrophic bacteria and archaea;
• The hydrological cycle, including using the H and O stable isotopic composition of modern or sedimentary lipid biomarkers to reconstruct hydrologic variability;
• The carbon cycle, including the use of 14C or the C stable isotopic composition of modern or sedimentary lipid biomarkers to constrain the source of organic matter;
• And change in nutrient cycling, including compound-specific nitrogen and carbon isotope ratios of amino acids.

We encourage work incorporating modern observations that expand our understanding on using lipid biomarkers to reconstruct past paleoenvironmental conditions in sedimentary archives, including from marine or terrestrial settings, and water column or sediment samples. We similarly welcome submissions that demonstrate clear limitations in applying or interpreting lipid-based proxies; new local, or regional lipid-based proxy calibrations; proxy system models; and work that expands on the use of compound-specific isotopes in sedimentary archives in any way.