Seasonal Controls on Litter and Soil Carbon and Nutrient Cycling in Arctic Tundra Ecosystems and Potential Impacts of Climate Change
Thesis (Ph.D, Biology) -- Queen's University, 2016-01-29 07:11:46.924 Climate change is leading to warmer temperatures and greater snowfall in Arctic regions. Microbial decomposition activities are strongly regulated by temperature, and therefore climate warming is projected to enhance decay of...
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ftqueensuniv:oai:https://qspace.library.queensu.ca:1974/13988 2024-06-02T08:01:24+00:00 Seasonal Controls on Litter and Soil Carbon and Nutrient Cycling in Arctic Tundra Ecosystems and Potential Impacts of Climate Change Christiansen, Casper Tai Biology Grogan, Paul 2016-01-29 07:11:46.924 application/pdf http://hdl.handle.net/1974/13988 eng eng Canadian theses http://hdl.handle.net/1974/13988 Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada ProQuest PhD and Master's Theses International Dissemination Agreement Intellectual Property Guidelines at Queen's University Copying and Preserving Your Thesis Creative Commons - Attribution-Non-commercial-No Derivate Works - CC BY-NC-ND This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. Climate Change Winter Ecosystem Ecology Arctic thesis 2016 ftqueensuniv 2024-05-06T10:47:32Z Thesis (Ph.D, Biology) -- Queen's University, 2016-01-29 07:11:46.924 Climate change is leading to warmer temperatures and greater snowfall in Arctic regions. Microbial decomposition activities are strongly regulated by temperature, and therefore climate warming is projected to enhance decay of the vast tundra soil organic matter pool, releasing CO2 into the atmosphere and nutrients into the soil solution. By contrast, increased soil nutrient availability promotes plant growth and changes in vegetation, both of which may enhance plant uptake of CO2 from the atmosphere. Consequently, depending on the net balance between these increases in CO2 release and uptake, tundra ecosystems may end up contributing globally significant feedbacks to a changing climate, further exacerbating environmental change. In this thesis, I modelled the effects of changes in seasonal climate on litter decay rates and ecosystem carbon (C) and nutrient pools in a variety of tundra vegetation-types. Specifically, I investigated how short- (one year) and longer-term (up to 9 years) experimentally-deepened winter snow and summer warming impact microbial communities and biogeochemical dynamics using experimental plots located in distinct ecosystems across the Canadian, Greenlandic, and Norwegian Arctic. Summer warming reduced surface litter decomposition in both relatively dry and wet ecosystems, likely because of evaporation-induced desiccation. In contrast, deepened snow had negligible effects on litter decay rates. However, tall birch shrub vegetation significantly stimulated litter decomposition, presumably due to a positive feedback from their greater litter inputs, enhancing soil nutrient pools and thereby microbial decomposition activities. Regarding plant and soil dynamics, the longer-term impacts of deepened snow included enhanced evergreen shrub growth and dominance over deciduous shrubs, but this increase in ecosystem C storage was dwarfed by 60 times greater soil C loss from the subsoil mineral layer. Soil bacterial community ... Thesis Arctic Climate change greenlandic Tundra Queen's University, Ontario: QSpace Arctic |
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Open Polar |
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Queen's University, Ontario: QSpace |
op_collection_id |
ftqueensuniv |
language |
English |
topic |
Climate Change Winter Ecosystem Ecology Arctic |
spellingShingle |
Climate Change Winter Ecosystem Ecology Arctic Christiansen, Casper Tai Seasonal Controls on Litter and Soil Carbon and Nutrient Cycling in Arctic Tundra Ecosystems and Potential Impacts of Climate Change |
topic_facet |
Climate Change Winter Ecosystem Ecology Arctic |
description |
Thesis (Ph.D, Biology) -- Queen's University, 2016-01-29 07:11:46.924 Climate change is leading to warmer temperatures and greater snowfall in Arctic regions. Microbial decomposition activities are strongly regulated by temperature, and therefore climate warming is projected to enhance decay of the vast tundra soil organic matter pool, releasing CO2 into the atmosphere and nutrients into the soil solution. By contrast, increased soil nutrient availability promotes plant growth and changes in vegetation, both of which may enhance plant uptake of CO2 from the atmosphere. Consequently, depending on the net balance between these increases in CO2 release and uptake, tundra ecosystems may end up contributing globally significant feedbacks to a changing climate, further exacerbating environmental change. In this thesis, I modelled the effects of changes in seasonal climate on litter decay rates and ecosystem carbon (C) and nutrient pools in a variety of tundra vegetation-types. Specifically, I investigated how short- (one year) and longer-term (up to 9 years) experimentally-deepened winter snow and summer warming impact microbial communities and biogeochemical dynamics using experimental plots located in distinct ecosystems across the Canadian, Greenlandic, and Norwegian Arctic. Summer warming reduced surface litter decomposition in both relatively dry and wet ecosystems, likely because of evaporation-induced desiccation. In contrast, deepened snow had negligible effects on litter decay rates. However, tall birch shrub vegetation significantly stimulated litter decomposition, presumably due to a positive feedback from their greater litter inputs, enhancing soil nutrient pools and thereby microbial decomposition activities. Regarding plant and soil dynamics, the longer-term impacts of deepened snow included enhanced evergreen shrub growth and dominance over deciduous shrubs, but this increase in ecosystem C storage was dwarfed by 60 times greater soil C loss from the subsoil mineral layer. Soil bacterial community ... |
author2 |
Biology Grogan, Paul |
format |
Thesis |
author |
Christiansen, Casper Tai |
author_facet |
Christiansen, Casper Tai |
author_sort |
Christiansen, Casper Tai |
title |
Seasonal Controls on Litter and Soil Carbon and Nutrient Cycling in Arctic Tundra Ecosystems and Potential Impacts of Climate Change |
title_short |
Seasonal Controls on Litter and Soil Carbon and Nutrient Cycling in Arctic Tundra Ecosystems and Potential Impacts of Climate Change |
title_full |
Seasonal Controls on Litter and Soil Carbon and Nutrient Cycling in Arctic Tundra Ecosystems and Potential Impacts of Climate Change |
title_fullStr |
Seasonal Controls on Litter and Soil Carbon and Nutrient Cycling in Arctic Tundra Ecosystems and Potential Impacts of Climate Change |
title_full_unstemmed |
Seasonal Controls on Litter and Soil Carbon and Nutrient Cycling in Arctic Tundra Ecosystems and Potential Impacts of Climate Change |
title_sort |
seasonal controls on litter and soil carbon and nutrient cycling in arctic tundra ecosystems and potential impacts of climate change |
publishDate |
2016 |
url |
http://hdl.handle.net/1974/13988 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Climate change greenlandic Tundra |
genre_facet |
Arctic Climate change greenlandic Tundra |
op_relation |
Canadian theses http://hdl.handle.net/1974/13988 |
op_rights |
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada ProQuest PhD and Master's Theses International Dissemination Agreement Intellectual Property Guidelines at Queen's University Copying and Preserving Your Thesis Creative Commons - Attribution-Non-commercial-No Derivate Works - CC BY-NC-ND This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
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1800745757116989440 |