Biogeochemical investigations of methane-rich groundwaters in high Arctic glacial catchments
Permafrost and glaciers in the high Arctic form a near-impermeable ‘cryospheric cap’ that traps a potentially large reservoir of sub-surface methane and prevents it from reaching the atmosphere. The vulnerability of the cryosphere to climate warming is making releases of this methane possible, but u...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/354051 2024-01-21T10:03:07+01:00 Biogeochemical investigations of methane-rich groundwaters in high Arctic glacial catchments Kleber, Gabrielle 2023-05-01 application/pdf https://www.repository.cam.ac.uk/handle/1810/354051 https://doi.org/10.17863/CAM.100060 eng eng University of Cambridge Department of Earth Sciences St Edmund's College https://www.repository.cam.ac.uk/handle/1810/354051 https://doi.org/10.17863/CAM.100060 All Rights Reserved https://www.rioxx.net/licenses/all-rights-reserved/ Arctic biogeochemistry glacier methane Thesis Doctoral Doctor of Philosophy (PhD) 2023 ftunivcam https://doi.org/10.17863/CAM.100060 2023-12-28T23:22:17Z Permafrost and glaciers in the high Arctic form a near-impermeable ‘cryospheric cap’ that traps a potentially large reservoir of sub-surface methane and prevents it from reaching the atmosphere. The vulnerability of the cryosphere to climate warming is making releases of this methane possible, but uncertainty in the magnitude and timing of such releases makes predictions of Arctic greenhouse gas emissions difficult. In Svalbard, where air temperatures are rising more than twice as fast as the average for the Arctic, glaciers are retreating and leaving behind exposed forefields that enable rapid methane escape. Through an extensive spatial study of proglacial groundwater springs on Svalbard, groundwater systems within glaciated catchments are found to be bringing to the surface deep-seated methane gas that was previously trapped beneath glaciers and permafrost in the Arctic. In this thesis, I estimate the amount of methane being released by such springs and discuss its origin. Through a temporal study conducted at a single glacial catchment, Vallåkrabreen, I use biogeochemical data collected from groundwaters during two melt seasons to investigate the sources of groundwaters and the origin of the methane they transport to the surface. Waters collected from 123 groundwater springs in the forefields of 78 land-terminating glaciers are supersaturated with methane up to 600,000-times greater than atmospheric equilibration. The spatial sampling revealed a geologic control on the extent of methane supersaturation, with strong evidence of a thermogenic source. I estimate annual methane emissions from proglacial groundwaters could be up to 2.31 kt across the Svalbard archipelago. Further investigations into marine-terminating glaciers indicate emergent methane emissions as these glaciers transition into fully land-based glaciers. My findings within the Vallåkrabreen catchment demonstrate an interconnected hydrological system where shallow and deep groundwaters mix to moderate methane emissions. During summer, deep ... Doctoral or Postdoctoral Thesis Arctic glacier permafrost Svalbard Apollo - University of Cambridge Repository Arctic Svalbard Svalbard Archipelago Vallåkrabreen ENVELOPE(16.983,16.983,77.817,77.817) |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
Arctic biogeochemistry glacier methane |
spellingShingle |
Arctic biogeochemistry glacier methane Kleber, Gabrielle Biogeochemical investigations of methane-rich groundwaters in high Arctic glacial catchments |
topic_facet |
Arctic biogeochemistry glacier methane |
description |
Permafrost and glaciers in the high Arctic form a near-impermeable ‘cryospheric cap’ that traps a potentially large reservoir of sub-surface methane and prevents it from reaching the atmosphere. The vulnerability of the cryosphere to climate warming is making releases of this methane possible, but uncertainty in the magnitude and timing of such releases makes predictions of Arctic greenhouse gas emissions difficult. In Svalbard, where air temperatures are rising more than twice as fast as the average for the Arctic, glaciers are retreating and leaving behind exposed forefields that enable rapid methane escape. Through an extensive spatial study of proglacial groundwater springs on Svalbard, groundwater systems within glaciated catchments are found to be bringing to the surface deep-seated methane gas that was previously trapped beneath glaciers and permafrost in the Arctic. In this thesis, I estimate the amount of methane being released by such springs and discuss its origin. Through a temporal study conducted at a single glacial catchment, Vallåkrabreen, I use biogeochemical data collected from groundwaters during two melt seasons to investigate the sources of groundwaters and the origin of the methane they transport to the surface. Waters collected from 123 groundwater springs in the forefields of 78 land-terminating glaciers are supersaturated with methane up to 600,000-times greater than atmospheric equilibration. The spatial sampling revealed a geologic control on the extent of methane supersaturation, with strong evidence of a thermogenic source. I estimate annual methane emissions from proglacial groundwaters could be up to 2.31 kt across the Svalbard archipelago. Further investigations into marine-terminating glaciers indicate emergent methane emissions as these glaciers transition into fully land-based glaciers. My findings within the Vallåkrabreen catchment demonstrate an interconnected hydrological system where shallow and deep groundwaters mix to moderate methane emissions. During summer, deep ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Kleber, Gabrielle |
author_facet |
Kleber, Gabrielle |
author_sort |
Kleber, Gabrielle |
title |
Biogeochemical investigations of methane-rich groundwaters in high Arctic glacial catchments |
title_short |
Biogeochemical investigations of methane-rich groundwaters in high Arctic glacial catchments |
title_full |
Biogeochemical investigations of methane-rich groundwaters in high Arctic glacial catchments |
title_fullStr |
Biogeochemical investigations of methane-rich groundwaters in high Arctic glacial catchments |
title_full_unstemmed |
Biogeochemical investigations of methane-rich groundwaters in high Arctic glacial catchments |
title_sort |
biogeochemical investigations of methane-rich groundwaters in high arctic glacial catchments |
publisher |
University of Cambridge |
publishDate |
2023 |
url |
https://www.repository.cam.ac.uk/handle/1810/354051 https://doi.org/10.17863/CAM.100060 |
long_lat |
ENVELOPE(16.983,16.983,77.817,77.817) |
geographic |
Arctic Svalbard Svalbard Archipelago Vallåkrabreen |
geographic_facet |
Arctic Svalbard Svalbard Archipelago Vallåkrabreen |
genre |
Arctic glacier permafrost Svalbard |
genre_facet |
Arctic glacier permafrost Svalbard |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/354051 https://doi.org/10.17863/CAM.100060 |
op_rights |
All Rights Reserved https://www.rioxx.net/licenses/all-rights-reserved/ |
op_doi |
https://doi.org/10.17863/CAM.100060 |
_version_ |
1788693381495390208 |