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Reductive Reactivity of Iron(III) Oxides in the East China Sea Sediments: Characterization by Selective Extraction and Kinetic Dissolution
Reactive Fe(III) oxides in gravity-core sediments collected from the East China Sea inner shelf were quantified by using three selective extractions (acidic hydroxylamine, acidic oxalate, bicarbonate-citrate buffered sodium dithionite). Also the reactivity of Fe(III) oxides in the sediments was char...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3829859/ https://www.ncbi.nlm.nih.gov/pubmed/24260377 http://dx.doi.org/10.1371/journal.pone.0080367 |
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author | Chen, Liang-Jin Zhu, Mao-Xu Yang, Gui-Peng Huang, Xiang-Li |
author_facet | Chen, Liang-Jin Zhu, Mao-Xu Yang, Gui-Peng Huang, Xiang-Li |
author_sort | Chen, Liang-Jin |
collection | PubMed |
description | Reactive Fe(III) oxides in gravity-core sediments collected from the East China Sea inner shelf were quantified by using three selective extractions (acidic hydroxylamine, acidic oxalate, bicarbonate-citrate buffered sodium dithionite). Also the reactivity of Fe(III) oxides in the sediments was characterized by kinetic dissolution using ascorbic acid as reductant at pH 3.0 and 7.5 in combination with the reactive continuum model. Three parameters derived from the kinetic method: m (0) (theoretical initial amount of ascorbate-reducible Fe(III) oxides), k′ (rate constant) and γ (heterogeneity of reactivity), enable a quantitative characterization of Fe(III) oxide reactivity in a standardized way. Amorphous Fe(III) oxides quantified by acidic hydroxylamine extraction were quickly consumed in the uppermost layer during early diagenesis but were not depleted over the upper 100 cm depth. The total amounts of amorphous and poorly crystalline Fe(III) oxides are highly available for efficient buffering of dissolved sulfide. As indicated by the m (0), k′ and γ, the surface sediments always have the maximum content, reactivity and heterogeneity of reactive Fe(III) oxides, while the three parameters simultaneously downcore decrease, much more quickly in the upper layer than at depth. Albeit being within a small range (within one order of magnitude) of the initial rates among sediments at different depths, incongruent dissolution could result in huge discrepancies of the later dissolution rates due to differentiating heterogeneity, which cannot be revealed by selective extraction. A strong linear correlation of the m (0) at pH 3.0 with the dithionite-extractable Fe(III) suggests that the m (0) may represent Fe(III) oxide assemblages spanning amorphous and crystalline Fe(III) oxides. Maximum microbially available Fe(III) predicted by the m (0) at pH 7.5 may include both amorphous and a fraction of other less reactive Fe(III) phases. |
format | Online Article Text |
id | pubmed-3829859 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-38298592013-11-20 Reductive Reactivity of Iron(III) Oxides in the East China Sea Sediments: Characterization by Selective Extraction and Kinetic Dissolution Chen, Liang-Jin Zhu, Mao-Xu Yang, Gui-Peng Huang, Xiang-Li PLoS One Research Article Reactive Fe(III) oxides in gravity-core sediments collected from the East China Sea inner shelf were quantified by using three selective extractions (acidic hydroxylamine, acidic oxalate, bicarbonate-citrate buffered sodium dithionite). Also the reactivity of Fe(III) oxides in the sediments was characterized by kinetic dissolution using ascorbic acid as reductant at pH 3.0 and 7.5 in combination with the reactive continuum model. Three parameters derived from the kinetic method: m (0) (theoretical initial amount of ascorbate-reducible Fe(III) oxides), k′ (rate constant) and γ (heterogeneity of reactivity), enable a quantitative characterization of Fe(III) oxide reactivity in a standardized way. Amorphous Fe(III) oxides quantified by acidic hydroxylamine extraction were quickly consumed in the uppermost layer during early diagenesis but were not depleted over the upper 100 cm depth. The total amounts of amorphous and poorly crystalline Fe(III) oxides are highly available for efficient buffering of dissolved sulfide. As indicated by the m (0), k′ and γ, the surface sediments always have the maximum content, reactivity and heterogeneity of reactive Fe(III) oxides, while the three parameters simultaneously downcore decrease, much more quickly in the upper layer than at depth. Albeit being within a small range (within one order of magnitude) of the initial rates among sediments at different depths, incongruent dissolution could result in huge discrepancies of the later dissolution rates due to differentiating heterogeneity, which cannot be revealed by selective extraction. A strong linear correlation of the m (0) at pH 3.0 with the dithionite-extractable Fe(III) suggests that the m (0) may represent Fe(III) oxide assemblages spanning amorphous and crystalline Fe(III) oxides. Maximum microbially available Fe(III) predicted by the m (0) at pH 7.5 may include both amorphous and a fraction of other less reactive Fe(III) phases. Public Library of Science 2013-11-15 /pmc/articles/PMC3829859/ /pubmed/24260377 http://dx.doi.org/10.1371/journal.pone.0080367 Text en © 2013 Chen 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 Chen, Liang-Jin Zhu, Mao-Xu Yang, Gui-Peng Huang, Xiang-Li Reductive Reactivity of Iron(III) Oxides in the East China Sea Sediments: Characterization by Selective Extraction and Kinetic Dissolution |
title | Reductive Reactivity of Iron(III) Oxides in the East China Sea Sediments: Characterization by Selective Extraction and Kinetic Dissolution |
title_full | Reductive Reactivity of Iron(III) Oxides in the East China Sea Sediments: Characterization by Selective Extraction and Kinetic Dissolution |
title_fullStr | Reductive Reactivity of Iron(III) Oxides in the East China Sea Sediments: Characterization by Selective Extraction and Kinetic Dissolution |
title_full_unstemmed | Reductive Reactivity of Iron(III) Oxides in the East China Sea Sediments: Characterization by Selective Extraction and Kinetic Dissolution |
title_short | Reductive Reactivity of Iron(III) Oxides in the East China Sea Sediments: Characterization by Selective Extraction and Kinetic Dissolution |
title_sort | reductive reactivity of iron(iii) oxides in the east china sea sediments: characterization by selective extraction and kinetic dissolution |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3829859/ https://www.ncbi.nlm.nih.gov/pubmed/24260377 http://dx.doi.org/10.1371/journal.pone.0080367 |
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