Biomarker Proxies for Paleoclimate Reconstruction in Peatlands

Peatlands form one of the most extensive terrestrial archives of past environmental change, accumulating plant and microbial residues over millennia. Biomarker proxies preserved within these deposits—ranging from long-chain n-alkanes and hopanes to cellulose-bound stable isotopes—capture variations in vegetation composition, hydrological balance and microbial activity. The distribution of n-alkane chain lengths and odd-even predominance provide insight into shifts between Sphagnum-dominated bogs and vascular-plant fens, while isotopic signatures (δ13C, δD and δ18O) trace changes in moisture sources, evapotranspiration and primary productivity. Lipid biomarkers derived from methanogenic archaea and methanotrophic bacteria record past methane cycling, offering direct constraints on greenhouse-gas feedbacks. Together, these molecular tools enable reconstruction of monsoon intensity, continental aridity, Holocene climatic oscillations and high-latitude permafrost dynamics. By linking proxy signals to modern calibration transects and process-based models, researchers refine age-depth chronologies and quantify uncertainties, advancing our understanding of peatland responses to natural and anthropogenic climate forcing.

Research from Nature Portfolio

Recent studies have employed compound-specific isotope analysis to elucidate peatland carbon dynamics under Holocene climate variability. Investigations of mid-Holocene peat in central China reveal decoupling between n-alkane hydrogen isotopes and regional stalagmite records, indicating intervals of pronounced drying that coincide with negative excursions in leaf-wax δ13C. These drought episodes accelerated peat respiration and enhanced bacterial hopane δ13C signatures, signalling intensified methane oxidation. In parallel, high-resolution profiles from the Tibetan Plateau integrate archaeal diether lipid abundances and diploptene δ13C values to map methanogenesis and methanotrophy through the Holocene. A marked reduction in methanogenic activity during the mid-Holocene dry phase underscores the sensitivity of peat emissions to monsoonal fluctuations and helps to resolve the mechanisms driving millennial-scale atmospheric methane trends.

Biomarker Proxies for Paleoclimate Reconstruction in Peatlands publication trend

The graph below shows the total number of articles in biomarker proxies for paleoclimate reconstruction in peatlands across all publications each year (not limited to Nature Index journals).

Technical terms

Biomarker proxy: An organic molecule preserved in sediments that reflects past environmental or biological conditions.

n-Alkanes: Long-chain hydrocarbons from plant waxes used to infer vegetation type and hydrological change.

Average Chain Length (ACL): Weighted mean of n-alkane chain lengths indicating dominant plant sources and climate influence.

Carbon Preference Index (CPI): Ratio of odd to even n-alkanes, signalling fresh plant input versus degradation.

Archaeal diether lipids: Glycerol dialkyl glycerol diether compounds produced by methanogenic archaea, used to track past methanogenesis.

Diploptene: A hopanoid lipid biomarker of bacterial methanotrophy that records methane oxidation activity.

α-Cellulose δ18O: Oxygen isotope ratio of plant cellulose, which reflects the isotopic composition of source water and evaporation effects.

References

1. Major moisture shifts in inland Northeast Asia during the last millennium. Environmental Research Letters (2024).
2. N-Alkanes in Permafrost Peatlands. Plants (2025).
3. Response of carbon cycle to drier conditions in the mid-Holocene in central China. Nature Communications (2018).
4. Holocene variations in peatland methane cycling associated with the Asian summer monsoon system. Nature Communications (2014).