Organic Proxies in Speleothem Paleoenvironmental Studies

Speleothems, the mineral deposits that form in caves, preserve trace amounts of organic compounds which act as proxies for reconstructing past environmental and climate conditions. Organic proxies encompass a range of molecular biomarkers—including combustion residues, plant‐derived polymers and microbial lipids—that become entrained within growing stalagmites and flowstones. Analysis of these compounds offers insight into historical fire regimes, vegetation dynamics, soil microbial activity and hydrological variability. Recent advances in extraction and mass-spectrometric techniques have improved detection limits, enabling high‐resolution records that complement traditional isotopic and elemental speleothem proxies. Interpretations must account for transport processes through karst systems, diagenetic alteration within the speleothem matrix and site-to-site variability. Globally, organic proxy studies have illuminated Holocene fire–climate links, shifts in regional vegetation cover and the influence of anthropogenic land use, demonstrating their wide applicability to paleoclimate research and resource management.

Research from Nature Portfolio

High-resolution analyses of a California Coast Range stalagmite have combined measurements of levoglucosan, a combustion‐sensitive anhydrosugar, with lignin oxidation products and traditional carbon and calcium isotopes to reconstruct fire activity and vegetation change across the 8.2 ka event. This multiproxy record reveals that episodes of hydroclimate whiplash—rapid oscillations between wet and dry conditions—were closely coupled with enhanced fire activity and a shift towards more woody plant communities. These findings underscore the sensitivity of semi-arid ecosystems to climate volatility and provide a long‐term analogue for anticipating the interaction between fire regimes and extreme hydrological fluctuations under future warming.

Organic Proxies in Speleothem Paleoenvironmental Studies publication trend

The graph below shows the total number of articles in organic proxies in speleothem paleoenvironmental studies across all publications each year (not limited to Nature Index journals).

Technical terms

Speleothem: Mineral deposit (stalagmite, stalactite) formed by cave dripwater that archives environmental signals.

Organic proxy: Molecular remnant preserved in geological material that indicates past environmental or biological conditions.

Biomarker: Organic compound of known biological origin used to infer past ecological or climatic states.

Levoglucosan: An anhydrosugar generated during cellulose combustion, used to reconstruct fire history.

Lignin oxidation products (LOPs): Monomeric compounds derived from lignin breakdown, employed to trace past vegetation types.

Polycyclic aromatic hydrocarbons (PAHs): Organic molecules produced by incomplete combustion, serving as indicators of fire activity.

References

1. Past fire dynamics inferred from polycyclic aromatic hydrocarbons and monosaccharide anhydrides in a stalagmite from the archaeological site of Mayapan, Mexico. Biogeosciences (2023).
2. Linked fire activity and climate whiplash in California during the early Holocene. Nature Communications (2022).
3. Quantification of lignin oxidation products as vegetation biomarkers in speleothems and cave drip water. Biogeosciences (2018).
4. Sources, Distribution and Paleoenvironmental Application of Fatty Acids in Speleothem Deposits From Krem Mawmluh, Northeast India. Frontiers in Earth Science (2021).