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Nitrogen Fuelling of the Pelagic Food Web of the Tropical Atlantic
We estimated the relative contribution of atmosphere (ic Nitrogen (N) input (wet and dry deposition and N fixation) to the epipelagic food web by measuring N isotopes of different functional groups of epipelagic zooplankton along 23°W (17°N-4°S) and 18°N (20-24°W) in the Eastern Tropical Atlantic. R...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4476781/ https://www.ncbi.nlm.nih.gov/pubmed/26098917 http://dx.doi.org/10.1371/journal.pone.0131258 |
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author | Sandel, Vera Kiko, Rainer Brandt, Peter Dengler, Marcus Stemmann, Lars Vandromme, Pieter Sommer, Ulrich Hauss, Helena |
author_facet | Sandel, Vera Kiko, Rainer Brandt, Peter Dengler, Marcus Stemmann, Lars Vandromme, Pieter Sommer, Ulrich Hauss, Helena |
author_sort | Sandel, Vera |
collection | PubMed |
description | We estimated the relative contribution of atmosphere (ic Nitrogen (N) input (wet and dry deposition and N fixation) to the epipelagic food web by measuring N isotopes of different functional groups of epipelagic zooplankton along 23°W (17°N-4°S) and 18°N (20-24°W) in the Eastern Tropical Atlantic. Results were related to water column observations of nutrient distribution and vertical diffusive flux as well as colony abundance of Trichodesmium obtained with an Underwater Vision Profiler (UVP5). The thickness and depth of the nitracline and phosphocline proved to be significant predictors of zooplankton stable N isotope values. Atmospheric N input was highest (61% of total N) in the strongly stratified and oligotrophic region between 3 and 7°N, which featured very high depth-integrated Trichodesmium abundance (up to 9.4×10(4) colonies m(-2)), strong thermohaline stratification and low zooplankton δ(15)N (~2‰). Relative atmospheric N input was lowest south of the equatorial upwelling between 3 and 5°S (27%). Values in the Guinea Dome region and north of Cape Verde ranged between 45 and 50%, respectively. The microstructure-derived estimate of the vertical diffusive N flux in the equatorial region was about one order of magnitude higher than in any other area (approximately 8 mmol m(-2) d( 1)). At the same time, this region received considerable atmospheric N input (35% of total). In general, zooplankton δ(15)N and Trichodesmium abundance were closely correlated, indicating that N fixation is the major source of atmospheric N input. Although Trichodesmium is not the only N fixing organism, its abundance can be used with high confidence to estimate the relative atmospheric N input in the tropical Atlantic (r(2) = 0.95). Estimates of absolute N fixation rates are two- to tenfold higher than incubation-derived rates reported for the same regions. Our approach integrates over large spatial and temporal scales and also quantifies fixed N released as dissolved inorganic and organic N. In a global analysis, it may thus help to close the gap in oceanic N budgets. |
format | Online Article Text |
id | pubmed-4476781 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-44767812015-06-25 Nitrogen Fuelling of the Pelagic Food Web of the Tropical Atlantic Sandel, Vera Kiko, Rainer Brandt, Peter Dengler, Marcus Stemmann, Lars Vandromme, Pieter Sommer, Ulrich Hauss, Helena PLoS One Research Article We estimated the relative contribution of atmosphere (ic Nitrogen (N) input (wet and dry deposition and N fixation) to the epipelagic food web by measuring N isotopes of different functional groups of epipelagic zooplankton along 23°W (17°N-4°S) and 18°N (20-24°W) in the Eastern Tropical Atlantic. Results were related to water column observations of nutrient distribution and vertical diffusive flux as well as colony abundance of Trichodesmium obtained with an Underwater Vision Profiler (UVP5). The thickness and depth of the nitracline and phosphocline proved to be significant predictors of zooplankton stable N isotope values. Atmospheric N input was highest (61% of total N) in the strongly stratified and oligotrophic region between 3 and 7°N, which featured very high depth-integrated Trichodesmium abundance (up to 9.4×10(4) colonies m(-2)), strong thermohaline stratification and low zooplankton δ(15)N (~2‰). Relative atmospheric N input was lowest south of the equatorial upwelling between 3 and 5°S (27%). Values in the Guinea Dome region and north of Cape Verde ranged between 45 and 50%, respectively. The microstructure-derived estimate of the vertical diffusive N flux in the equatorial region was about one order of magnitude higher than in any other area (approximately 8 mmol m(-2) d( 1)). At the same time, this region received considerable atmospheric N input (35% of total). In general, zooplankton δ(15)N and Trichodesmium abundance were closely correlated, indicating that N fixation is the major source of atmospheric N input. Although Trichodesmium is not the only N fixing organism, its abundance can be used with high confidence to estimate the relative atmospheric N input in the tropical Atlantic (r(2) = 0.95). Estimates of absolute N fixation rates are two- to tenfold higher than incubation-derived rates reported for the same regions. Our approach integrates over large spatial and temporal scales and also quantifies fixed N released as dissolved inorganic and organic N. In a global analysis, it may thus help to close the gap in oceanic N budgets. Public Library of Science 2015-06-22 /pmc/articles/PMC4476781/ /pubmed/26098917 http://dx.doi.org/10.1371/journal.pone.0131258 Text en © 2015 Sandel et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Sandel, Vera Kiko, Rainer Brandt, Peter Dengler, Marcus Stemmann, Lars Vandromme, Pieter Sommer, Ulrich Hauss, Helena Nitrogen Fuelling of the Pelagic Food Web of the Tropical Atlantic |
title | Nitrogen Fuelling of the Pelagic Food Web of the Tropical Atlantic |
title_full | Nitrogen Fuelling of the Pelagic Food Web of the Tropical Atlantic |
title_fullStr | Nitrogen Fuelling of the Pelagic Food Web of the Tropical Atlantic |
title_full_unstemmed | Nitrogen Fuelling of the Pelagic Food Web of the Tropical Atlantic |
title_short | Nitrogen Fuelling of the Pelagic Food Web of the Tropical Atlantic |
title_sort | nitrogen fuelling of the pelagic food web of the tropical atlantic |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4476781/ https://www.ncbi.nlm.nih.gov/pubmed/26098917 http://dx.doi.org/10.1371/journal.pone.0131258 |
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