Nitrogen isotopes in the Atlantic and Pacific oxygen minimum zones
As a limiting element for biological productivity, nitrogen occupies a central role in ocean biogeochemistry. It exists in more chemical forms than most other elements, with a myriad of chemical transformations that are unique to this element. Nearly all these transformations are undertaken by marin...
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ftoceanrep:oai:oceanrep.geomar.de:11892 2024-09-15T18:24:20+00:00 Nitrogen isotopes in the Atlantic and Pacific oxygen minimum zones Ryabenko, Evgenia 2011 text https://oceanrep.geomar.de/id/eprint/11892/ https://oceanrep.geomar.de/id/eprint/11892/1/Diss_Ryabenko_N-Isotopes_web.pdf https://macau.uni-kiel.de/receive/diss_mods_00006584 en eng https://oceanrep.geomar.de/id/eprint/11892/1/Diss_Ryabenko_N-Isotopes_web.pdf Ryabenko, E. (2011) Nitrogen isotopes in the Atlantic and Pacific oxygen minimum zones. Open Access (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, Germany, 130 pp. UrhG info:eu-repo/semantics/openAccess Thesis NonPeerReviewed 2011 ftoceanrep 2024-08-19T23:40:11Z As a limiting element for biological productivity, nitrogen occupies a central role in ocean biogeochemistry. It exists in more chemical forms than most other elements, with a myriad of chemical transformations that are unique to this element. Nearly all these transformations are undertaken by marine organisms as part of their metabolism, which involves isotopic fractionation. Thus stable isotopes of nitrogen carry important information on sources and sinks of nitrogen and its transformation within the oceanic cycle. This dissertation focused on the nitrogen cycle in two very different ocean regions: the Eastern Tropical North Atlantic and the Eastern Tropical South Pacific. These two basins are associated with Oxygen Minimum Zones (OMZs), which have a great influence on the global nitrogen cycle. The first part of the thesis describes the method used for nitrogen isotope measurement. The method was used to contrast the two OMZs, to investigate what processes are dominating in each of them and how they influence the global nitrogen cycle. The nitrogen cycle in the Atlantic OMZ is dominated by nitrification and dust deposition, which could be detected in nitrogen isotope (δ15N) signatures. In the Pacific OMZ, effects of nitrogen loss processes were most pronounced. The nitrogen fractionation factor, however, was much smaller than expected (11.4‰ instead of 20 – 30‰), which was most probably was an effect of denitrification in sediments. The last two parts are devoted to the Pacific OMZ nitrogen cycle. δ15N in water column and surface sediments showed a parallel latitudinal increase from north to south along the Peru margin, which correlates with intensification of the OMZ. From water column data it was showed that N-loss processes indirectly influence the δ15N found in the surface sediments (δ15Nsed). Latitudinal distribution of δ15Nsed along the South American coast, however, showed a very good correlation with surface water nitrogen utilization, outshining N-loss processes. This correlation is not surprising as ... Thesis North Atlantic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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Open Polar |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
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English |
description |
As a limiting element for biological productivity, nitrogen occupies a central role in ocean biogeochemistry. It exists in more chemical forms than most other elements, with a myriad of chemical transformations that are unique to this element. Nearly all these transformations are undertaken by marine organisms as part of their metabolism, which involves isotopic fractionation. Thus stable isotopes of nitrogen carry important information on sources and sinks of nitrogen and its transformation within the oceanic cycle. This dissertation focused on the nitrogen cycle in two very different ocean regions: the Eastern Tropical North Atlantic and the Eastern Tropical South Pacific. These two basins are associated with Oxygen Minimum Zones (OMZs), which have a great influence on the global nitrogen cycle. The first part of the thesis describes the method used for nitrogen isotope measurement. The method was used to contrast the two OMZs, to investigate what processes are dominating in each of them and how they influence the global nitrogen cycle. The nitrogen cycle in the Atlantic OMZ is dominated by nitrification and dust deposition, which could be detected in nitrogen isotope (δ15N) signatures. In the Pacific OMZ, effects of nitrogen loss processes were most pronounced. The nitrogen fractionation factor, however, was much smaller than expected (11.4‰ instead of 20 – 30‰), which was most probably was an effect of denitrification in sediments. The last two parts are devoted to the Pacific OMZ nitrogen cycle. δ15N in water column and surface sediments showed a parallel latitudinal increase from north to south along the Peru margin, which correlates with intensification of the OMZ. From water column data it was showed that N-loss processes indirectly influence the δ15N found in the surface sediments (δ15Nsed). Latitudinal distribution of δ15Nsed along the South American coast, however, showed a very good correlation with surface water nitrogen utilization, outshining N-loss processes. This correlation is not surprising as ... |
format |
Thesis |
author |
Ryabenko, Evgenia |
spellingShingle |
Ryabenko, Evgenia Nitrogen isotopes in the Atlantic and Pacific oxygen minimum zones |
author_facet |
Ryabenko, Evgenia |
author_sort |
Ryabenko, Evgenia |
title |
Nitrogen isotopes in the Atlantic and Pacific oxygen minimum zones |
title_short |
Nitrogen isotopes in the Atlantic and Pacific oxygen minimum zones |
title_full |
Nitrogen isotopes in the Atlantic and Pacific oxygen minimum zones |
title_fullStr |
Nitrogen isotopes in the Atlantic and Pacific oxygen minimum zones |
title_full_unstemmed |
Nitrogen isotopes in the Atlantic and Pacific oxygen minimum zones |
title_sort |
nitrogen isotopes in the atlantic and pacific oxygen minimum zones |
publishDate |
2011 |
url |
https://oceanrep.geomar.de/id/eprint/11892/ https://oceanrep.geomar.de/id/eprint/11892/1/Diss_Ryabenko_N-Isotopes_web.pdf https://macau.uni-kiel.de/receive/diss_mods_00006584 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://oceanrep.geomar.de/id/eprint/11892/1/Diss_Ryabenko_N-Isotopes_web.pdf Ryabenko, E. (2011) Nitrogen isotopes in the Atlantic and Pacific oxygen minimum zones. Open Access (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, Germany, 130 pp. |
op_rights |
UrhG info:eu-repo/semantics/openAccess |
_version_ |
1810464664124915712 |