Denitrification and hydrologic transient storage in a glacial meltwater stream, McMurdo Dry Valleys, Antarctica
In extreme environments, retention of nutrients within stream ecosystems contributes to the persistence of aquatic biota and continuity of ecosystem function. In the McMurdo Dry Valleys, Antarctica, many glacial meltwater streams flow for only 5–12 weeks a year and yet support extensive benthic micr...
Published in: | Limnology and Oceanography |
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crwiley:10.4319/lo.2004.49.5.1884 2024-06-23T07:45:51+00:00 Denitrification and hydrologic transient storage in a glacial meltwater stream, McMurdo Dry Valleys, Antarctica Gooseff, Michael N. McKnight, Diane M. Runkel, Robert L. Duff, John H. 2004 http://dx.doi.org/10.4319/lo.2004.49.5.1884 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.2004.49.5.1884 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2004.49.5.1884 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Limnology and Oceanography volume 49, issue 5, page 1884-1895 ISSN 0024-3590 1939-5590 journal-article 2004 crwiley https://doi.org/10.4319/lo.2004.49.5.1884 2024-06-11T04:48:27Z In extreme environments, retention of nutrients within stream ecosystems contributes to the persistence of aquatic biota and continuity of ecosystem function. In the McMurdo Dry Valleys, Antarctica, many glacial meltwater streams flow for only 5–12 weeks a year and yet support extensive benthic microbial communities. We investigated NO 3 − uptake and denitrification in Green Creek by analyzing small‐scale microbial mat dynamics in mesocosms and reach‐scale nutrient cycling in two whole‐stream NO 3 − enrichment experiments. Nitrate uptake results indicated that microbial mats were nitrogen (N)‐limited, with NO 3 − uptake rates as high as 16 nmol N cm −2 h −1 . Denitrification potentials associated with microbial mats were also as high as 16 nmol N cm −2 h −1 . During two whole‐stream NO 3 − −enrichment experiments, a simultaneous pulse of NO 2 − was observed in the stream water. The one‐dimensional solute transport model with inflow and storage was modified to simulate two storage zones: one to account for short time scale hydrologic exchange of stream water into and out of the benthic microbial mat, the other to account for longer time scale hydrologic exchange with the hyporheic zone. Simulations indicate that injected NO 3 − was removed both in the microbial mat and in the hyporheic zone and that as much as 20% of the NO 3 − that entered the microbial mat and hyporheic zone was transformed to NO 2 − by dissimilatory reduction. Because of the rapid hydrologic exchange in microbial mats, it is likely that denitrification is limited either by biotic assimilation, reductase limitation, or transport limitation (reduced NO 2 − is transported away from reducing microbes). Article in Journal/Newspaper Antarc* Antarctica McMurdo Dry Valleys Wiley Online Library McMurdo Dry Valleys Limnology and Oceanography 49 5 1884 1895 |
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Wiley Online Library |
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English |
description |
In extreme environments, retention of nutrients within stream ecosystems contributes to the persistence of aquatic biota and continuity of ecosystem function. In the McMurdo Dry Valleys, Antarctica, many glacial meltwater streams flow for only 5–12 weeks a year and yet support extensive benthic microbial communities. We investigated NO 3 − uptake and denitrification in Green Creek by analyzing small‐scale microbial mat dynamics in mesocosms and reach‐scale nutrient cycling in two whole‐stream NO 3 − enrichment experiments. Nitrate uptake results indicated that microbial mats were nitrogen (N)‐limited, with NO 3 − uptake rates as high as 16 nmol N cm −2 h −1 . Denitrification potentials associated with microbial mats were also as high as 16 nmol N cm −2 h −1 . During two whole‐stream NO 3 − −enrichment experiments, a simultaneous pulse of NO 2 − was observed in the stream water. The one‐dimensional solute transport model with inflow and storage was modified to simulate two storage zones: one to account for short time scale hydrologic exchange of stream water into and out of the benthic microbial mat, the other to account for longer time scale hydrologic exchange with the hyporheic zone. Simulations indicate that injected NO 3 − was removed both in the microbial mat and in the hyporheic zone and that as much as 20% of the NO 3 − that entered the microbial mat and hyporheic zone was transformed to NO 2 − by dissimilatory reduction. Because of the rapid hydrologic exchange in microbial mats, it is likely that denitrification is limited either by biotic assimilation, reductase limitation, or transport limitation (reduced NO 2 − is transported away from reducing microbes). |
format |
Article in Journal/Newspaper |
author |
Gooseff, Michael N. McKnight, Diane M. Runkel, Robert L. Duff, John H. |
spellingShingle |
Gooseff, Michael N. McKnight, Diane M. Runkel, Robert L. Duff, John H. Denitrification and hydrologic transient storage in a glacial meltwater stream, McMurdo Dry Valleys, Antarctica |
author_facet |
Gooseff, Michael N. McKnight, Diane M. Runkel, Robert L. Duff, John H. |
author_sort |
Gooseff, Michael N. |
title |
Denitrification and hydrologic transient storage in a glacial meltwater stream, McMurdo Dry Valleys, Antarctica |
title_short |
Denitrification and hydrologic transient storage in a glacial meltwater stream, McMurdo Dry Valleys, Antarctica |
title_full |
Denitrification and hydrologic transient storage in a glacial meltwater stream, McMurdo Dry Valleys, Antarctica |
title_fullStr |
Denitrification and hydrologic transient storage in a glacial meltwater stream, McMurdo Dry Valleys, Antarctica |
title_full_unstemmed |
Denitrification and hydrologic transient storage in a glacial meltwater stream, McMurdo Dry Valleys, Antarctica |
title_sort |
denitrification and hydrologic transient storage in a glacial meltwater stream, mcmurdo dry valleys, antarctica |
publisher |
Wiley |
publishDate |
2004 |
url |
http://dx.doi.org/10.4319/lo.2004.49.5.1884 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.2004.49.5.1884 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2004.49.5.1884 |
geographic |
McMurdo Dry Valleys |
geographic_facet |
McMurdo Dry Valleys |
genre |
Antarc* Antarctica McMurdo Dry Valleys |
genre_facet |
Antarc* Antarctica McMurdo Dry Valleys |
op_source |
Limnology and Oceanography volume 49, issue 5, page 1884-1895 ISSN 0024-3590 1939-5590 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.4319/lo.2004.49.5.1884 |
container_title |
Limnology and Oceanography |
container_volume |
49 |
container_issue |
5 |
container_start_page |
1884 |
op_container_end_page |
1895 |
_version_ |
1802642626754641920 |