Dynamique du méthane et du dioxyde de carbone dans les mares de thermokarst du Québec subarctique
The thawing and subsidence of ice-rich permafrost mounds results in the formation of thermokarst lakes and ponds. These waters are known to emit CH₄ and CO₂, but the biogeochemical dynamics of these emissions remain poorly understood. The objectives of this thesis study were to assess major sources...
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fttriple:oai:gotriple.eu:http://hdl.handle.net/20.500.11794/29872 2023-05-15T15:23:04+02:00 Dynamique du méthane et du dioxyde de carbone dans les mares de thermokarst du Québec subarctique Methane and carbon dioxide dynamics in Québec subarctic thermokarst mares Matveev, Alex Vincent, Warwick F. Laurion, Isabelle Arctique Québec (Province) 2018-01-01 https://hdl.handle.net/20.500.11794/29872 fr fre Université Laval http://hdl.handle.net/20.500.11794/29872 other CorpusUL geo envir Thesis https://vocabularies.coar-repositories.org/resource_types/c_46ec/ 2018 fttriple https://doi.org/20.500.11794/29872 2023-01-22T18:38:31Z The thawing and subsidence of ice-rich permafrost mounds results in the formation of thermokarst lakes and ponds. These waters are known to emit CH₄ and CO₂, but the biogeochemical dynamics of these emissions remain poorly understood. The objectives of this thesis study were to assess major sources of variability in estimates of greenhouse gas emissions from thermokarst lakes formed on permafrost of divergent carbon content, and to evaluate some of the non-linear changes in these freshwater ecosystems that may arise from global warming. CH₄ and CO₂ stocks and fluxes were measured in 18 thermokarst lakes in six biogeochemically distinct sub-regions of subarctic Quebec, along a permafrost degradation gradient. These sites contain thermokarst lakes that are derived either from the thawing of palsas (frozen peat mounds) or lithalsas (mineral permafrost mounds), which differ in their soil organic carbon content. To address the potential effect of permafrost degradation on these freshwater systems under climate warming, comparative sites were selected in the northern discontinuous permafrost zone and in the southern sporadic permafrost zone where permafrost is more rapidly degrading. Winter profiling of five lakes located on eroding permafrost peatlands was undertaken, and automated water temperature, conductivity and oxygen loggers were used to evaluate how the annual cycle of stratification and mixing may affect the release of greenhouse gases to the atmosphere. The studied lakes were thermally stratified for most of the year, with strong physico-chemical gradients down the water column, and most had anoxic bottom waters. The northernmost lithalsa lakes varied in their surface-water CO₂ content, from below to above saturation, but the southern lakes in this gradient had much higher surface concentrations that were well above air-equilibrium. Surface-water CH₄ concentrations were at least an order of magnitude above air-equilibrium at all lithalsa sites, and the diffusive fluxes of both gases increased from north to ... Thesis Arctique* Ice palsas permafrost Subarctic subarctique* Thermokarst Unknown |
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language |
French |
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geo envir |
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geo envir Matveev, Alex Dynamique du méthane et du dioxyde de carbone dans les mares de thermokarst du Québec subarctique |
topic_facet |
geo envir |
description |
The thawing and subsidence of ice-rich permafrost mounds results in the formation of thermokarst lakes and ponds. These waters are known to emit CH₄ and CO₂, but the biogeochemical dynamics of these emissions remain poorly understood. The objectives of this thesis study were to assess major sources of variability in estimates of greenhouse gas emissions from thermokarst lakes formed on permafrost of divergent carbon content, and to evaluate some of the non-linear changes in these freshwater ecosystems that may arise from global warming. CH₄ and CO₂ stocks and fluxes were measured in 18 thermokarst lakes in six biogeochemically distinct sub-regions of subarctic Quebec, along a permafrost degradation gradient. These sites contain thermokarst lakes that are derived either from the thawing of palsas (frozen peat mounds) or lithalsas (mineral permafrost mounds), which differ in their soil organic carbon content. To address the potential effect of permafrost degradation on these freshwater systems under climate warming, comparative sites were selected in the northern discontinuous permafrost zone and in the southern sporadic permafrost zone where permafrost is more rapidly degrading. Winter profiling of five lakes located on eroding permafrost peatlands was undertaken, and automated water temperature, conductivity and oxygen loggers were used to evaluate how the annual cycle of stratification and mixing may affect the release of greenhouse gases to the atmosphere. The studied lakes were thermally stratified for most of the year, with strong physico-chemical gradients down the water column, and most had anoxic bottom waters. The northernmost lithalsa lakes varied in their surface-water CO₂ content, from below to above saturation, but the southern lakes in this gradient had much higher surface concentrations that were well above air-equilibrium. Surface-water CH₄ concentrations were at least an order of magnitude above air-equilibrium at all lithalsa sites, and the diffusive fluxes of both gases increased from north to ... |
author2 |
Vincent, Warwick F. Laurion, Isabelle |
format |
Thesis |
author |
Matveev, Alex |
author_facet |
Matveev, Alex |
author_sort |
Matveev, Alex |
title |
Dynamique du méthane et du dioxyde de carbone dans les mares de thermokarst du Québec subarctique |
title_short |
Dynamique du méthane et du dioxyde de carbone dans les mares de thermokarst du Québec subarctique |
title_full |
Dynamique du méthane et du dioxyde de carbone dans les mares de thermokarst du Québec subarctique |
title_fullStr |
Dynamique du méthane et du dioxyde de carbone dans les mares de thermokarst du Québec subarctique |
title_full_unstemmed |
Dynamique du méthane et du dioxyde de carbone dans les mares de thermokarst du Québec subarctique |
title_sort |
dynamique du méthane et du dioxyde de carbone dans les mares de thermokarst du québec subarctique |
publisher |
Université Laval |
publishDate |
2018 |
url |
https://hdl.handle.net/20.500.11794/29872 |
op_coverage |
Arctique Québec (Province) |
genre |
Arctique* Ice palsas permafrost Subarctic subarctique* Thermokarst |
genre_facet |
Arctique* Ice palsas permafrost Subarctic subarctique* Thermokarst |
op_source |
CorpusUL |
op_relation |
http://hdl.handle.net/20.500.11794/29872 |
op_rights |
other |
op_doi |
https://doi.org/20.500.11794/29872 |
_version_ |
1766353755969683456 |