Thawing glacial and permafrost features contribute to nitrogen export from Green Lakes Valley, Colorado Front Range, USA
Abstract Alpine ecosystems are particularly sus-ceptible to disturbance due to their short growing seasons, sparse vegetation and thin soils. Increased nitrogen deposition in wetfall and changes in climate currently affect Green Lakes Valley within the Col-orado Front Range. Research conducted withi...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.646.4350 2023-05-15T17:57:15+02:00 Thawing glacial and permafrost features contribute to nitrogen export from Green Lakes Valley, Colorado Front Range, USA The Pennsylvania State University CiteSeerX Archives 2013 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.646.4350 http://snobear.colorado.edu/Markw/Research/13_barnes.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.646.4350 http://snobear.colorado.edu/Markw/Research/13_barnes.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://snobear.colorado.edu/Markw/Research/13_barnes.pdf text 2013 ftciteseerx 2016-01-08T16:11:37Z Abstract Alpine ecosystems are particularly sus-ceptible to disturbance due to their short growing seasons, sparse vegetation and thin soils. Increased nitrogen deposition in wetfall and changes in climate currently affect Green Lakes Valley within the Col-orado Front Range. Research conducted within the alpine links chronic nitrogen inputs to a suite of ecological impacts, resulting in increased nitrate export. The atmospheric nitrogen flux decreased by 0.56 kg ha-1 year-1 between 2000 and 2009, due to decreased precipitation; however alpine nitrate yields increased by 40 % relative to the previous decade (1990–1999). Long term trends indicate that weath-ering products such as sulfate, calcium, and silica have also increased over the same period. The geochemical composition of thawing permafrost, as indicated by rock glacial and blockfield meltwater, suggests it is the source of these weathering products. Furthermore, mass balance models indicate the high ammonium loads within glacial meltwater are rapidly nitrified, contributing *0.5–1.4 kg N ha-1 to the growing season nitrate flux from the alpine watershed. The sustained export of these solutes during dry, summer months is likely facilitated by thawing cryosphere providing hydraulic connectivity late into the growing season. This mechanism is further supported by the lack of upward weathering or nitrogen solute trends in a neighboring catchment which lacks permafrost and glacial features. These findings suggest that reductions of atmospheric nitrogen deposition alone may not improve water quality, as cryospheric thaw exposes soils to biological and geochemical processes that may affect alpine nitrate concentrations as much as atmo-spheric deposition trends. Text permafrost Unknown |
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Abstract Alpine ecosystems are particularly sus-ceptible to disturbance due to their short growing seasons, sparse vegetation and thin soils. Increased nitrogen deposition in wetfall and changes in climate currently affect Green Lakes Valley within the Col-orado Front Range. Research conducted within the alpine links chronic nitrogen inputs to a suite of ecological impacts, resulting in increased nitrate export. The atmospheric nitrogen flux decreased by 0.56 kg ha-1 year-1 between 2000 and 2009, due to decreased precipitation; however alpine nitrate yields increased by 40 % relative to the previous decade (1990–1999). Long term trends indicate that weath-ering products such as sulfate, calcium, and silica have also increased over the same period. The geochemical composition of thawing permafrost, as indicated by rock glacial and blockfield meltwater, suggests it is the source of these weathering products. Furthermore, mass balance models indicate the high ammonium loads within glacial meltwater are rapidly nitrified, contributing *0.5–1.4 kg N ha-1 to the growing season nitrate flux from the alpine watershed. The sustained export of these solutes during dry, summer months is likely facilitated by thawing cryosphere providing hydraulic connectivity late into the growing season. This mechanism is further supported by the lack of upward weathering or nitrogen solute trends in a neighboring catchment which lacks permafrost and glacial features. These findings suggest that reductions of atmospheric nitrogen deposition alone may not improve water quality, as cryospheric thaw exposes soils to biological and geochemical processes that may affect alpine nitrate concentrations as much as atmo-spheric deposition trends. |
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The Pennsylvania State University CiteSeerX Archives |
format |
Text |
title |
Thawing glacial and permafrost features contribute to nitrogen export from Green Lakes Valley, Colorado Front Range, USA |
spellingShingle |
Thawing glacial and permafrost features contribute to nitrogen export from Green Lakes Valley, Colorado Front Range, USA |
title_short |
Thawing glacial and permafrost features contribute to nitrogen export from Green Lakes Valley, Colorado Front Range, USA |
title_full |
Thawing glacial and permafrost features contribute to nitrogen export from Green Lakes Valley, Colorado Front Range, USA |
title_fullStr |
Thawing glacial and permafrost features contribute to nitrogen export from Green Lakes Valley, Colorado Front Range, USA |
title_full_unstemmed |
Thawing glacial and permafrost features contribute to nitrogen export from Green Lakes Valley, Colorado Front Range, USA |
title_sort |
thawing glacial and permafrost features contribute to nitrogen export from green lakes valley, colorado front range, usa |
publishDate |
2013 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.646.4350 http://snobear.colorado.edu/Markw/Research/13_barnes.pdf |
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permafrost |
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permafrost |
op_source |
http://snobear.colorado.edu/Markw/Research/13_barnes.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.646.4350 http://snobear.colorado.edu/Markw/Research/13_barnes.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766165638353518592 |