Dynamics of carbon capture in Scottish and Irish peatlands over the past centuries

Because peatlands store and potentially release large amounts of carbon, predicting their role in future warming is essential (e.g., Gallego-Sala et al., 2018; Ferretto et al. 2019). The aim of this project is to quantify the carbon dynamics in near-pristine and damaged bogs over the past 4-5 centuries, and to assess possible relationships between carbon burial rates and environmental dynamics. Relationships between carbon accumulation, local vegetation and water tables in the bogs will be explored using plant macrofossil and testate amoebae analyses.

Robust chronologies are essential for reliable centennial-scale reconstructions of carbon accumulation within bogs. However, large natural and human-made changes in atmospheric 14C content over the past 4-5 centuries cause imprecise 14C chronologies, and current 210Pb-based chronologies are inflexible and incapable of incorporating other dates. This project will be among the first to combine 14C and 210Pb dates through a newly published Bayesian alternative (Aquino et al., 2018), in order to produce enhanced, precise and more flexible chronologies with realistic uncertainty estimates.

Four peat profiles in Northern Ireland and Scotland will be investigated at high resolution in order to produce highly detailed time series of carbon accumulation spanning the past ~500 years. Together with existing contemporary monitoring of fluxes of CO2 and CH4 from bogs by the Hutton Institute, this will enable enhanced estimates of carbon fluxes to, within and from peatlands. By combining high-resolution 14C and 210Pb data, we will for the first time be able to independently test the universally accepted assumption of a constant 210Pb flux. If we find varying 210Pb fluxes, then many existing 210Pb-based chronologies are flawed. Thus this project could have implications for the role of peat bogs in carbon accumulation as well as for 210Pb-based studies across the world.

The student will be required to undertake fieldwork on Scottish and Northern Irish bogs, perform laboratory analyses (14C, 210Pb, macrofossils, testate amoebae) and undertake some programming.