A first multi-proxy palaeoecological record from a tropical peatland in Guyana, NE South America

Tropical peatlands are among the most carbon-dense ecosystems on Earth, yet their long-term development and responses to environmental change remain poorly understood. Palaeoecological records from the Guianas region in particular are extremely limited, resulting in a major gap in our understanding of tropical peatland dynamics. This study presents the first multi-proxy palaeoecological investigation of tropical peatlands in Guyana, providing new insights into peatland development, carbon dynamics, and environmental variability in this under-researched region.

This study analyses two peat cores from lowland tropical peatlands in Guyana, which represent different hydrological and vegetation settings. The cores have been analysed using various complementary proxies, including macroscopic charcoal analysis to reconstruct past fire activity, thermogravimetric analysis (TGA) to characterise changes in organic matter composition, stable carbon and nitrogen isotope analyses (δ¹³C and δ¹⁵N) to investigate vegetation inputs and biogeochemical processes, and pollen analysis to assess vegetation dynamics. Radiocarbon dating provides a chronological framework for interpreting proxy evidence for past conditions and peat accumulation history.

Results reveal variability in charcoal abundance, organic matter composition, and isotopic signatures, suggesting changes in peat accumulation processes and environmental conditions through time. Charcoal-rich layers indicate episodic fire activity, while pollen assemblages reveal shifts in local and/or regional vegetation composition. Differences observed between the two cores indicate spatial variability in fire history and peatland development, potentially driven by local hydrological conditions, vegetation type, or human influence.

Integrated multi-proxy records from both peat cores link fire history, vegetation change, and organic matter characteristics within chronological frameworks. This study provides a critical first baseline for understanding the long-term dynamics of Guyanese peatlands and contributes to broader efforts to assess the vulnerability and resilience of tropical peat carbon stores under future climate and land-use change.The results are also timely, as in the field we observed substantial fire-induced peat loss following the 2023–2024 El Niño event which likely resulted in significant greenhouse gas emissions. Overall, the findings highlight the value of multi-proxy palaeoecological approaches for reconstructing peatland development in understudied tropical regions.