Nitrogen retention in the riparian zone of watersheds underlain by discontinuous permafrost
Thesis (M.S.) University of Alaska Fairbanks, 2005 Riparian zones function as important ecotones for reducing nitrate concentration in groundwater and inputs into streams. In the boreal forest of interior Alaska, permafrost confines subsurface flow through the riparian zone to shallow organic horizo...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/6921 2023-05-15T15:53:35+02:00 Nitrogen retention in the riparian zone of watersheds underlain by discontinuous permafrost O'Donnell, Jonathan A. 2005-05 http://hdl.handle.net/11122/6921 en_US eng http://hdl.handle.net/11122/6921 Biology and Wildlife Department Thesis ms 2005 ftunivalaska 2023-02-23T21:36:44Z Thesis (M.S.) University of Alaska Fairbanks, 2005 Riparian zones function as important ecotones for reducing nitrate concentration in groundwater and inputs into streams. In the boreal forest of interior Alaska, permafrost confines subsurface flow through the riparian zone to shallow organic horizons, where plant uptake of nitrate and denitrification are typically high. Two research questions were addressed in this study: 1) how does riparian zone nitrogen retention vary in watersheds underlain by discontinuous permafrost, and 2) what is the contribution of denitrification to riparian zone nitrogen retention? To estimate the contribution of the riparian zone to watershed nitrogen retention, I analyzed groundwater chemistry using an end-member mixing model. To assess the importance of denitrification as a mechanism of nitrogen retention, I conducted field denitrification assays using the acetylene block technique. Over the summer, nitrogen retention averaged 0.75 and 0.22 mmol N m⁻² d⁻¹ in low and high permafrost watersheds, respectively. Compared with the fluvial export of nitrogen, the retention rate of nitrogen in the riparian zone is 10 - 15% of the loss rate in stream flow. Denitrification accounted for a small proportion (3%) of total nitrogen retention in the riparian zone. Variation in nitrogen retention between watersheds did not account for differences in stream nitrate concentration between watersheds. Introduction -- Factors controlling denitrification -- Riparian zones as nutrient filters -- Models of riparian zone function -- Permafrost and hydrology -- Caribou Poker Creeks Research Watershed (CPCRW) -- References -- Nitrogen retention in the riparian zone of watersheds underlain by discontinuous permafrost -- Conclusions -- References. Thesis Caribou-Poker Creeks Research Watershed permafrost Alaska University of Alaska: ScholarWorks@UA Fairbanks |
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University of Alaska: ScholarWorks@UA |
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English |
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Thesis (M.S.) University of Alaska Fairbanks, 2005 Riparian zones function as important ecotones for reducing nitrate concentration in groundwater and inputs into streams. In the boreal forest of interior Alaska, permafrost confines subsurface flow through the riparian zone to shallow organic horizons, where plant uptake of nitrate and denitrification are typically high. Two research questions were addressed in this study: 1) how does riparian zone nitrogen retention vary in watersheds underlain by discontinuous permafrost, and 2) what is the contribution of denitrification to riparian zone nitrogen retention? To estimate the contribution of the riparian zone to watershed nitrogen retention, I analyzed groundwater chemistry using an end-member mixing model. To assess the importance of denitrification as a mechanism of nitrogen retention, I conducted field denitrification assays using the acetylene block technique. Over the summer, nitrogen retention averaged 0.75 and 0.22 mmol N m⁻² d⁻¹ in low and high permafrost watersheds, respectively. Compared with the fluvial export of nitrogen, the retention rate of nitrogen in the riparian zone is 10 - 15% of the loss rate in stream flow. Denitrification accounted for a small proportion (3%) of total nitrogen retention in the riparian zone. Variation in nitrogen retention between watersheds did not account for differences in stream nitrate concentration between watersheds. Introduction -- Factors controlling denitrification -- Riparian zones as nutrient filters -- Models of riparian zone function -- Permafrost and hydrology -- Caribou Poker Creeks Research Watershed (CPCRW) -- References -- Nitrogen retention in the riparian zone of watersheds underlain by discontinuous permafrost -- Conclusions -- References. |
format |
Thesis |
author |
O'Donnell, Jonathan A. |
spellingShingle |
O'Donnell, Jonathan A. Nitrogen retention in the riparian zone of watersheds underlain by discontinuous permafrost |
author_facet |
O'Donnell, Jonathan A. |
author_sort |
O'Donnell, Jonathan A. |
title |
Nitrogen retention in the riparian zone of watersheds underlain by discontinuous permafrost |
title_short |
Nitrogen retention in the riparian zone of watersheds underlain by discontinuous permafrost |
title_full |
Nitrogen retention in the riparian zone of watersheds underlain by discontinuous permafrost |
title_fullStr |
Nitrogen retention in the riparian zone of watersheds underlain by discontinuous permafrost |
title_full_unstemmed |
Nitrogen retention in the riparian zone of watersheds underlain by discontinuous permafrost |
title_sort |
nitrogen retention in the riparian zone of watersheds underlain by discontinuous permafrost |
publishDate |
2005 |
url |
http://hdl.handle.net/11122/6921 |
geographic |
Fairbanks |
geographic_facet |
Fairbanks |
genre |
Caribou-Poker Creeks Research Watershed permafrost Alaska |
genre_facet |
Caribou-Poker Creeks Research Watershed permafrost Alaska |
op_relation |
http://hdl.handle.net/11122/6921 Biology and Wildlife Department |
_version_ |
1766388705464942592 |