Organic Geochemistry of Lacustrine Sediments

Organic geochemistry of lacustrine sediments examines the origin, transformation and fate of organic matter deposited in lake basins. Sedimentary organic matter comprises a mixture of terrestrial plant debris, algal remnants and microbial residues, each carrying molecular signatures that reflect past environmental conditions. Key analytical approaches include bulk measurements of total organic carbon (TOC) and nitrogen, compound-specific isotopic analysis (notably δ13Corg), and the profiling of lipid biomarkers such as n-alkanes, sterols and fatty acids. These proxies allow reconstruction of primary productivity, vegetation shifts, hydrological changes and anthropogenic impacts over decadal to millennial timescales. Diagenetic processes—microbial degradation, selective preservation and mineral association—modulate biomarker distributions, influencing the quality and quantity of organic carbon burial. Indices such as the carbon preference index (CPI) or average chain length (ACL) of long-chain hydrocarbons gauge the degree of alteration and source contributions. Studies across diverse climatic regions have demonstrated that lacustrine sediments serve as both archives of palaeoclimate change and significant carbon sinks, with implications for regional carbon budgets and predictions of future carbon sequestration under global change scenarios. Advances in multi-proxy integration and high-resolution sampling have refined our understanding of organic matter dynamics, linking molecular signals to nutrient cycling, redox conditions and ecosystem shifts. The global significance of these records lies in their capacity to inform water management, palaeoenvironmental reconstruction and climate mitigation strategies.

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Organic Geochemistry of Lacustrine Sediments publication trend

The graph below shows the total number of articles in organic geochemistry of lacustrine sediments across all publications each year (not limited to Nature Index journals).

Technical terms

Lacustrine sediments: Layers of deposited material in lake basins, containing mineral particles and organic matter derived from in-lake and catchment sources.

Lipid biomarkers: Specific organic molecules (e.g. n-alkanes, fatty acids, sterols) preserved in sediments that trace biological sources and past environmental conditions.

n-Alkanes: Straight-chain hydrocarbons with odd-numbered carbon chains, commonly used to distinguish terrestrial plant inputs (long chains) from algal and microbial sources (short to mid chains).

Total organic carbon (TOC): The proportion of organic carbon in a sediment sample, indicating overall organic matter content.

Carbon preference index (CPI): Ratio of odd- to even-numbered n-alkane homologues, used to assess organic matter maturity, degradation and source contributions.

δ13Corg: The ratio of stable carbon isotopes (13C/12C) in organic matter, expressed relative to a standard, which reflects photosynthetic pathways and environmental conditions.

References

1. Lipid biomarkers in high mountain lakes from the Cantabrian range (Northern Spain): Coupling the interplay between natural and anthropogenic drivers. Anthropocene (2024).
2. Investigation of Modern n-Alkanes in Daihai Lake Basin, Northern China: Implications for the Interpretation of Paleoclimate Research. Frontiers in Earth Science (2022).
3. Long-term preservation of biomolecules in lake sediments: potential importance of physical shielding by recalcitrant cell walls. PNAS Nexus (2022).