Hyporheic Exchange and Water Chemistry of Two Arctic Tundra Streams of Contrasting Geomorphology
The North Slope of Alaska’s Brooks Range is underlain by continuous permafrost, but an active layer of thawed sediments develops at the tundra surface and beneath streambeds during the summer, facilitating hyporheic exchange. Our goal was to understand how active layer extent and stream geomorpholog...
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ftboisestateu:oai:scholarworks.boisestate.edu:geo_facpubs-1018 2023-10-29T02:33:53+01:00 Hyporheic Exchange and Water Chemistry of Two Arctic Tundra Streams of Contrasting Geomorphology Greenwald, Morgan J. Bowden, William B. Gooseff, Michael N. Zarnetske, Jay P. McNamara, James P. Bradford, John H. Brosten, Troy R. 2008-06-12T07:00:00Z application/pdf https://scholarworks.boisestate.edu/geo_facpubs/19 https://scholarworks.boisestate.edu/context/geo_facpubs/article/1018/viewcontent/McNamara___Hyporheic_exchange.pdf unknown ScholarWorks https://scholarworks.boisestate.edu/geo_facpubs/19 https://scholarworks.boisestate.edu/context/geo_facpubs/article/1018/viewcontent/McNamara___Hyporheic_exchange.pdf Copyright 2008 by the American Geophysical Union. DOI: 10.1029/2007JG000549 Geosciences Faculty Publications and Presentations hyporheic zone arctic streams nutrient cycling biogeochemistry geomorphology CGISS Earth Sciences Geophysics and Seismology text 2008 ftboisestateu 2023-09-29T15:03:46Z The North Slope of Alaska’s Brooks Range is underlain by continuous permafrost, but an active layer of thawed sediments develops at the tundra surface and beneath streambeds during the summer, facilitating hyporheic exchange. Our goal was to understand how active layer extent and stream geomorphology influence hyporheic exchange and nutrient chemistry. We studied two arctic tundra streams of contrasting geomorphology: a high-gradient, alluvial stream with riffle-pool sequences and a low-gradient, peat-bottomed stream with large deep pools connected by deep runs. Hyporheic exchange occurred to ~50 cm beneath the alluvial streambed and to only ~15 cm beneath the peat streambed. The thaw bulb was deeper than the hyporheic exchange zone in both stream types. The hyporheic zone was a net source of ammonium and soluble reactive phosphorus in both stream types. The hyporheic zone was a net source of nitrate in the alluvial stream, but a net nitrate sink in the peat stream. The mass flux of nutrients regenerated from the hyporheic zones in these two streams was a small portion of the surface water mass flux. Although small, hyporheic sources of regenerated nutrients help maintain the in-stream nutrient balance. If future warming in the arctic increases the depth of the thaw bulb, it may not increase the vertical extent of hyporheic exchange. The greater impacts on annual contributions of hyporheic regeneration are likely to be due to longer thawed seasons, increased sediment temperatures or changes in geomorphology. Text Arctic Brooks Range permafrost Tundra Boise State University: Scholar Works |
institution |
Open Polar |
collection |
Boise State University: Scholar Works |
op_collection_id |
ftboisestateu |
language |
unknown |
topic |
hyporheic zone arctic streams nutrient cycling biogeochemistry geomorphology CGISS Earth Sciences Geophysics and Seismology |
spellingShingle |
hyporheic zone arctic streams nutrient cycling biogeochemistry geomorphology CGISS Earth Sciences Geophysics and Seismology Greenwald, Morgan J. Bowden, William B. Gooseff, Michael N. Zarnetske, Jay P. McNamara, James P. Bradford, John H. Brosten, Troy R. Hyporheic Exchange and Water Chemistry of Two Arctic Tundra Streams of Contrasting Geomorphology |
topic_facet |
hyporheic zone arctic streams nutrient cycling biogeochemistry geomorphology CGISS Earth Sciences Geophysics and Seismology |
description |
The North Slope of Alaska’s Brooks Range is underlain by continuous permafrost, but an active layer of thawed sediments develops at the tundra surface and beneath streambeds during the summer, facilitating hyporheic exchange. Our goal was to understand how active layer extent and stream geomorphology influence hyporheic exchange and nutrient chemistry. We studied two arctic tundra streams of contrasting geomorphology: a high-gradient, alluvial stream with riffle-pool sequences and a low-gradient, peat-bottomed stream with large deep pools connected by deep runs. Hyporheic exchange occurred to ~50 cm beneath the alluvial streambed and to only ~15 cm beneath the peat streambed. The thaw bulb was deeper than the hyporheic exchange zone in both stream types. The hyporheic zone was a net source of ammonium and soluble reactive phosphorus in both stream types. The hyporheic zone was a net source of nitrate in the alluvial stream, but a net nitrate sink in the peat stream. The mass flux of nutrients regenerated from the hyporheic zones in these two streams was a small portion of the surface water mass flux. Although small, hyporheic sources of regenerated nutrients help maintain the in-stream nutrient balance. If future warming in the arctic increases the depth of the thaw bulb, it may not increase the vertical extent of hyporheic exchange. The greater impacts on annual contributions of hyporheic regeneration are likely to be due to longer thawed seasons, increased sediment temperatures or changes in geomorphology. |
format |
Text |
author |
Greenwald, Morgan J. Bowden, William B. Gooseff, Michael N. Zarnetske, Jay P. McNamara, James P. Bradford, John H. Brosten, Troy R. |
author_facet |
Greenwald, Morgan J. Bowden, William B. Gooseff, Michael N. Zarnetske, Jay P. McNamara, James P. Bradford, John H. Brosten, Troy R. |
author_sort |
Greenwald, Morgan J. |
title |
Hyporheic Exchange and Water Chemistry of Two Arctic Tundra Streams of Contrasting Geomorphology |
title_short |
Hyporheic Exchange and Water Chemistry of Two Arctic Tundra Streams of Contrasting Geomorphology |
title_full |
Hyporheic Exchange and Water Chemistry of Two Arctic Tundra Streams of Contrasting Geomorphology |
title_fullStr |
Hyporheic Exchange and Water Chemistry of Two Arctic Tundra Streams of Contrasting Geomorphology |
title_full_unstemmed |
Hyporheic Exchange and Water Chemistry of Two Arctic Tundra Streams of Contrasting Geomorphology |
title_sort |
hyporheic exchange and water chemistry of two arctic tundra streams of contrasting geomorphology |
publisher |
ScholarWorks |
publishDate |
2008 |
url |
https://scholarworks.boisestate.edu/geo_facpubs/19 https://scholarworks.boisestate.edu/context/geo_facpubs/article/1018/viewcontent/McNamara___Hyporheic_exchange.pdf |
genre |
Arctic Brooks Range permafrost Tundra |
genre_facet |
Arctic Brooks Range permafrost Tundra |
op_source |
Geosciences Faculty Publications and Presentations |
op_relation |
https://scholarworks.boisestate.edu/geo_facpubs/19 https://scholarworks.boisestate.edu/context/geo_facpubs/article/1018/viewcontent/McNamara___Hyporheic_exchange.pdf |
op_rights |
Copyright 2008 by the American Geophysical Union. DOI: 10.1029/2007JG000549 |
_version_ |
1781056163516776448 |