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Can nitrogen isotopes be used to detect the effects of burning on nitrogen cycling? : a study on Pinus resinosa in Minnesota, USA
Pinus resinosa stands in Minnesota, USA were surveyed and fine and coarse roots from stands were analysed for nitrogen isotopes in an attempt to determine if fire effects nitrogen cycling. Fire increased the % nitrogen of coarse roots and changed the ratio of C: N. It may also decrease the depth of...
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| Format: | Thesis |
| Language: | English |
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Department of Biological Sciences
2017
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| _version_ | 1867613291103125504 |
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| access_status_str | Open Access |
| author | Ballantyne, Fiona |
| author2 | Craine, Joseph M |
| author_browse | Ballantyne, Fiona Craine, Joseph M |
| author_facet | Craine, Joseph M Ballantyne, Fiona |
| author_sort | Ballantyne, Fiona |
| collection | Thesis |
| description | Pinus resinosa stands in Minnesota, USA were surveyed and fine and coarse roots from stands were analysed for nitrogen isotopes in an attempt to determine if fire effects nitrogen cycling. Fire increased the % nitrogen of coarse roots and changed the ratio of C: N. It may also decrease the depth of the A-horizon. It did not however affect the nitrogen isotope ratio of stands. Isotope values of coarse roots were affected by the depth of the A-horizon, which is consistent with other studies. A correlation between the ¹⁵N values of coarse and fine roots was found however fine roots were enriched proportionately to coarse roots. This suggests that they may be using a more enriched source of nitrogen such as ammonia although this is not conclusive. A PCA performed on site variables and isotope values determined the two major axes for sites were bum history and nitrogen cycle openness but that burning did not affect the second axis. A stepwise backwards regression showed the best predictors of a roots isotope value were, in decreasing order, the isotope value of coarse roots for fine roots and vice versa, the % nitrogen of roots and the age of stands. Coarse and fine roots showed opposite trends with % nitrogen. As the % nitrogen increased, fine roots were more ¹⁵N enriched, again pointing to different nitrogen sources for coarse and fine roots. Older stands do appear to have a more open nitrogen cycle, as roots were ¹⁵N enriched in these stands. The availability of different forms of nitrogen may influence the ¹⁵N signal of roots especially if fine roots are preferentially using ammonia. Therefore, it is not possible to say if isotope values are due to stand openness, or due to different resources use by roots. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/26118 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:48.261Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2017 |
| publishDateRange | 2017 |
| publishDateSort | 2017 |
| publisher | Department of Biological Sciences |
| publisherStr | Department of Biological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/26118 Can nitrogen isotopes be used to detect the effects of burning on nitrogen cycling? : a study on Pinus resinosa in Minnesota, USA Ballantyne, Fiona Craine, Joseph M Botany Plant Ecology Pinus resinosa stands in Minnesota, USA were surveyed and fine and coarse roots from stands were analysed for nitrogen isotopes in an attempt to determine if fire effects nitrogen cycling. Fire increased the % nitrogen of coarse roots and changed the ratio of C: N. It may also decrease the depth of the A-horizon. It did not however affect the nitrogen isotope ratio of stands. Isotope values of coarse roots were affected by the depth of the A-horizon, which is consistent with other studies. A correlation between the ¹⁵N values of coarse and fine roots was found however fine roots were enriched proportionately to coarse roots. This suggests that they may be using a more enriched source of nitrogen such as ammonia although this is not conclusive. A PCA performed on site variables and isotope values determined the two major axes for sites were bum history and nitrogen cycle openness but that burning did not affect the second axis. A stepwise backwards regression showed the best predictors of a roots isotope value were, in decreasing order, the isotope value of coarse roots for fine roots and vice versa, the % nitrogen of roots and the age of stands. Coarse and fine roots showed opposite trends with % nitrogen. As the % nitrogen increased, fine roots were more ¹⁵N enriched, again pointing to different nitrogen sources for coarse and fine roots. Older stands do appear to have a more open nitrogen cycle, as roots were ¹⁵N enriched in these stands. The availability of different forms of nitrogen may influence the ¹⁵N signal of roots especially if fine roots are preferentially using ammonia. Therefore, it is not possible to say if isotope values are due to stand openness, or due to different resources use by roots. 2017-11-10T06:30:28Z 2017-11-10T06:30:28Z 2004 2017-03-10T14:41:30Z Bachelor Thesis Honours BSc (Hons) http://hdl.handle.net/11427/26118 eng application/pdf Department of Biological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Botany Plant Ecology Ballantyne, Fiona Can nitrogen isotopes be used to detect the effects of burning on nitrogen cycling? : a study on Pinus resinosa in Minnesota, USA |
| thesis_degree_str | Bachelor's / Honours |
| title | Can nitrogen isotopes be used to detect the effects of burning on nitrogen cycling? : a study on Pinus resinosa in Minnesota, USA |
| title_full | Can nitrogen isotopes be used to detect the effects of burning on nitrogen cycling? : a study on Pinus resinosa in Minnesota, USA |
| title_fullStr | Can nitrogen isotopes be used to detect the effects of burning on nitrogen cycling? : a study on Pinus resinosa in Minnesota, USA |
| title_full_unstemmed | Can nitrogen isotopes be used to detect the effects of burning on nitrogen cycling? : a study on Pinus resinosa in Minnesota, USA |
| title_short | Can nitrogen isotopes be used to detect the effects of burning on nitrogen cycling? : a study on Pinus resinosa in Minnesota, USA |
| title_sort | can nitrogen isotopes be used to detect the effects of burning on nitrogen cycling a study on pinus resinosa in minnesota usa |
| topic | Botany Plant Ecology |
| url | http://hdl.handle.net/11427/26118 |
| work_keys_str_mv | AT ballantynefiona cannitrogenisotopesbeusedtodetecttheeffectsofburningonnitrogencyclingastudyonpinusresinosainminnesotausa |