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Developing transfer functions for peatland carbon dynamics: testing the viability of testate amoebae as CO₂ and CH₄ proxies
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Date
2025-12-01
Authors
Dela Pena, Xyza Vasily
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Publisher
University College Cork
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Abstract
The objective of this study was to investigate and model the relationship between testate amoeba assemblages and CO2 and CH4 fluxes across ecohydrological and temporal gradients at Clara Bog, Ireland. While contemporary greenhouse gas (GHG) monitoring provides high-resolution data, a significant gap exists in reconstructing long-term, regional CO2 and CH4 dynamics from the peat archive. Current palaeo-carbon methods often cannot distinguish between specific gas fluxes, necessitating the development of a proxy-based approach. To assess the ecosystem dynamics, this study combined a long-term greenhouse gas (GHG) monitoring programme (2021–2025) with seasonal biological sampling. Field data for both approaches were collected via 24 permanent collars distributed across four distinct ecotopes. To ensure spatial consistency, composite vegetation samples were collected from six permanently marked points around each collar periphery. Numerical methods, including weighted averaging (WA), weighted averaging partial least squares (WA-PLS), and Maximum Likelihood Response Curves (MLRC), were employed to develop inference models for both seasonal living assemblages and multi-year integrated (sub-fossil) communities. Results demonstrated a significant decoupling between high-frequency environmental volatility and biological response. While CH4 flux exhibited extreme seasonal fluctuations (up to a 420-fold difference), the living testate amoeba assemblages remained compositionally stable. In contrast, the spatial gradient across ecotopes provided a robust signal, allowing for the development of high-performing multi-year integrated models. These models successfully filtered transient environmental noise, revealing strong, statistically significant relationships between community structure and mean GHG flux. Weighted averaging identified distinct niche partitioning, with wet-ecotope taxa (Hyalosphenia papilio, Archerella flavum) exhibiting broader CH4 tolerances than drier taxa (Euglypha rotunda, Corythion dubium). This research demonstrated that testate amoeba-based inference models can effectively integrate long-term carbon dynamics, providing a pioneering methodology for reconstructing high-resolution CH4 and CO2 trajectories from the peat archive.
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Keywords
Peatland , Methane , Carbon , Testate amoebae , Peatland carbon dynamics , Transfer functions , Greenhouse gas monitoring , Clara Bog , Ombrotrophic peatland , Weighted averaging–partial least squares (WA-PLS) , Palaeoenvironmental reconstruction , Peatland ecohydrology , Bioindicators
Citation
Dela Pena, X. V. 2025. Developing transfer functions for peatland carbon dynamics: testing the viability of testate amoebae as CO₂ and CH₄ proxies. MRes Thesis, University College Cork.