Fluvial carbon dynamics in degraded peatland catchments

  • Andrew Stimson

Student thesis: Phd

Abstract

Inland waters including streams, rivers, reservoirs and lakes are regarded as a significant site of Organic Carbon (OC) cycling, and greenhouse gas production. As a result, there has been significant recent interest in the rates and fate of fluvial carbon exported from organic soils, such as peatlands. Additionally, peatlands can be subject to substantial degradation resulting in high rates of fluvial OC export, and this has led to efforts to repair degraded peatlands through restoration programmes. As a consequence, the study of degraded areas is useful to quantify the upper values of carbon release, understand processes of transformation, and evaluate the success of restoration programmes. Importantly peatlands are also collection areas for drinking water, which has implications for treatment, and requires better understanding of carbon cycling upstream of treatment works, in headwater rivers, reservoirs and pipes. UK upland blanket peat catchments are a key location in which to consider global questions surrounding fluvial carbon export and transformations, as they are highly degraded, provide a source of drinking water supply, and are currently undergoing pioneering methods of landscape scale restoration. This thesis considers Kinder Scout, an area of highly degraded and gullied blanket peatland in the South Pennines, UK. Using analysis of water samples collected over several years in the Kinder reservoir catchment and plateau, this thesis presents three novel contributions to global questions concerning OC cycling and peatlands. Firstly it provides (to date), the only carbon budget for a reservoir in a peat dominated catchment with high Particulate Organic Carbon (POC) export, which demonstrates that reservoirs may be net sources of Dissolved Organic Carbon (DOC), with the implication that POC-DOC interactions are important OC transformation mechanism in degraded systems. Secondly through use of a unique integrated combination of methods, it considers changes in carbon flux and composition in both river, lake and pipe locations, providing detailed understanding of the relative roles of river reaches, reservoirs and supply pipes, in controlling fluvial carbon cycling in peatland systems, and upstream of water treatment works. An important implication here, is that rate and direction of change in water treatability varies through a catchment. Finally, it includes results from the first widespread monitoring of the catchment scale effects of a new method of peatland revegetation. This restoration approach is being applied at landscape scale and the findings here, are that despite fears to the contrary, it does not lead to short term increases in fluvial carbon loss, which is an important piece of evidence supporting practical conservation approaches in these systems. To further enhance this research, a combination of field and laboratory investigations into carbon transformation processes, and ongoing restoration mentoring should be undertaken.
Date of Award1 Aug 2016
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorMartin Evans (Supervisor) & Tim Allott (Supervisor)

Keywords

  • Carbon transformations
  • Carbon composition
  • Peatland restoration
  • Water treatment
  • DOC
  • Reservoirs
  • Lakes
  • POC
  • Peatlands
  • Carbon cycle

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