Detecting ancient carbon leaking from permafrost soils across the Arctic
Joshua Dean, University of Liverpool
Richard Chiverrell, University of Liverpool
- External Supervisors:
Mark Garnett (NERC Radiocarbon Facility)
Jorien Vonk (Vrije Universiteit [Free University], Amsterdam)
Joshua Dean (University of Liverpool) email@example.com
- CASE Partner:
Application deadline: 10 January 2020
Arctic soils store vast amounts of carbon that can thaw and drive climate feedback loops, producing CO2 and CH4, as global temperatures rise (1). Inland freshwater (lakes, rivers, streams and ponds) are considered hotspots for greenhouse gas (GHG) emissions in the Arctic. The Arctic is covered by up to 50% open water in places, and initial field campaigns show that GHG concentrations in these waters can be substantially higher than other major inland freshwater ecosystems (e.g. the Amazon and Congo river systems). This indicates that inland waters are a key aspect of the Arctic carbon budget.
Detecting the release of ancient carbon that was previously stored in permafrost soils for hundreds or even thousands of years into inland waters remains a significant technical challenge (2). Understanding the dynamics of this ancient carbon is critical to predicting climate change because of the magnitude of these GHG fluxes, and the potential significance of the Arctic carbon pool as a climate feedback.
Recent work by the supervisory team has found that simply identifying ancient carbon in aquatic ecosystems does not necessarily constitute a positive climate feedback (3). The candidate will explore the age of carbon in Arctic inland waters and develop a modelling and conceptual framework to determine whether ancient aquatic carbon fluxes are significant at local, regional and global scales. This project will provide critical benchmark observations for quantifying Arctic inland water GHG emissions, the contribution of permafrost thaw to these emissions, and their importance to the global carbon cycle.Project Summary:
- Establish modeling and conceptual frameworks to identify enhanced release of ancient carbon from permafrost catchments due to climate change and landscape disturbance.
- Determine how release of ancient carbon can vary through time and space in Arctic inland waters.
The project will involve fieldwork in the Siberian Arctic at the Kytalyk research station in conjunction with a larger project led by the Free University Amsterdam. The candidate will also have opportunities to work in the Canadian, Alaskan and European Arctic.
The candidate will combine new and existing data on permafrost aquatic radiocarbon (14C) measurements, in which the supervisory team are leading experts (3, 4). The candidate will develop a framework to compare the age of aquatic carbon export with expected exports based on soil, climate and vegetation characteristics of Arctic catchments.
The candidate will collect field data to support this synthesis using a range of inland water ecosystems identified at study sites in Siberia. The student will explore how temporal variations affect the release of ancient carbon relative to the magnitude of landscape carbon dynamics. This includes novel 14C measurements and high temporal resolution GHG flux measurements using cavity ring down spectroscopy and eddy covariance. The project involves site visits in the snow-free season and the frozen Spring and Autumn periods, and therefore requires a candidate suited to challenging fieldwork conditions with the potential for extremely novel and rare samples collected from one of the most remote locations in the world.References:
(1) Dean, JF et al. (2018a). Methane feedbacks to the global climate systems in a warmer world. Reviews of Geophysics 56, 207-250.
(2) Elder, CD et al. (2018). Greenhouse gas emissions from diverse Arctic Alaskan lakes are dominated by young carbon. Nature Climate Change 8, 166-171.
(3) Dean, JF et al. (2018b). Abundant pre-industrial carbon detected in Canadian Arctic headwaters: implications for the permafrost carbon feedback. Environmental Research letters 13, 034024.
(4) Vonk, JE et al. (2012). Activation of old carbon by erosion of coastal and subsea permafrost in Arctic Siberia. Nature 489, 137-140.