Magnetotactic bacterial response to Antarctic dust supply during the Palaeocene–Eocene thermal maximum
Distinct magnetic properties of marine sediments that record the Palaeocene–Eocene thermal maximum (PETM) have been suggested to be due to a bacterial magnetofossil signal that is linked to enhanced weathering conditions during the PETM. We document the dominance of bacterial magnetite in deep-sea s...
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Online Access: | http://hdl.handle.net/10261/276961 https://doi.org/10.1016/j.epsl.2012.04.003 |
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ftcsic:oai:digital.csic.es:10261/276961 2024-02-11T09:57:39+01:00 Magnetotactic bacterial response to Antarctic dust supply during the Palaeocene–Eocene thermal maximum Larrasoaña, Juan C. Roberts, Andrew P. Liao, Chang Schellenberg, Stephen A. Fitz Gerald, John D. Norris, Richard D. Zachos, James C. Meseta Kerguelen, Océano Índico 2012-05-17 http://hdl.handle.net/10261/276961 https://doi.org/10.1016/j.epsl.2012.04.003 en eng Elsevier https://www.sciencedirect.com/science/article/abs/pii/S0012821X12001707 Earth and Planetary Science Letters, vol.333–334, 122-133 1385-013X http://hdl.handle.net/10261/276961 https://doi.org/10.1016/j.epsl.2012.04.003 open Palaeocene/Eocene thermal maximum marine sediments environmental magnetism biogenic magnetite aeolian dust Meseta Kerguelen Océano Índico artículo 2012 ftcsic https://doi.org/10.1016/j.epsl.2012.04.003 2024-01-16T11:27:47Z Distinct magnetic properties of marine sediments that record the Palaeocene–Eocene thermal maximum (PETM) have been suggested to be due to a bacterial magnetofossil signal that is linked to enhanced weathering conditions during the PETM. We document the dominance of bacterial magnetite in deep-sea sediments from southern Kerguelen Plateau (Ocean Drilling Program Hole 738C, southern Ocean) not only during the PETM, but also before and after the thermal event. This occurrence of magnetofossils throughout the PETM indicates that the occurrence of bacterial magnetosomes is not due to a preservation effect. Instead, we suggest that it is due to sustained mild iron-reducing conditions that dissolved the most labile aeolian-derived iron, which favoured continued magnetotactic bacterial activity without being strong enough to dissolve the less reactive magnetite and haematite. Enhanced aeolian haematite abundances at the beginning of the PETM indicate drier conditions on the neighbouring Antarctic continent at those times. Our results provide evidence that iron fertilisation by aeolian dust was the main limiting factor that conditioned proliferation of magnetotactic bacteria in the deep sea at the southern Kerguelen Plateau, with the exception of two short periods of rapidly changing palaeoenvironmental conditions at the onset and termination of the PETM. Increased iron supply from aeolian dust, that enhanced oceanic primary productivity and subsequent delivery of organic carbon to the seafloor, along with mild iron-reducing diagenetic conditions, seem to have been necessary to provide the iron needed for magnetite biomineralization by magnetotactic bacteria to drive their marked increase in abundance in the studied PETM record from southern Kerguelen Plateau. Our analyses of a deep-sea PETM record from Hole 1051B at Blake Nose (Atlantic Ocean) failed to identify magnetofossils despite evidence for the occurrence of magnetite and haematite of probable aeolian origin. Contrasting magnetic properties at these PETM ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Digital.CSIC (Spanish National Research Council) Antarctic Kerguelen Southern Ocean Earth and Planetary Science Letters 333-334 122 133 |
institution |
Open Polar |
collection |
Digital.CSIC (Spanish National Research Council) |
op_collection_id |
ftcsic |
language |
English |
topic |
Palaeocene/Eocene thermal maximum marine sediments environmental magnetism biogenic magnetite aeolian dust Meseta Kerguelen Océano Índico |
spellingShingle |
Palaeocene/Eocene thermal maximum marine sediments environmental magnetism biogenic magnetite aeolian dust Meseta Kerguelen Océano Índico Larrasoaña, Juan C. Roberts, Andrew P. Liao, Chang Schellenberg, Stephen A. Fitz Gerald, John D. Norris, Richard D. Zachos, James C. Magnetotactic bacterial response to Antarctic dust supply during the Palaeocene–Eocene thermal maximum |
topic_facet |
Palaeocene/Eocene thermal maximum marine sediments environmental magnetism biogenic magnetite aeolian dust Meseta Kerguelen Océano Índico |
description |
Distinct magnetic properties of marine sediments that record the Palaeocene–Eocene thermal maximum (PETM) have been suggested to be due to a bacterial magnetofossil signal that is linked to enhanced weathering conditions during the PETM. We document the dominance of bacterial magnetite in deep-sea sediments from southern Kerguelen Plateau (Ocean Drilling Program Hole 738C, southern Ocean) not only during the PETM, but also before and after the thermal event. This occurrence of magnetofossils throughout the PETM indicates that the occurrence of bacterial magnetosomes is not due to a preservation effect. Instead, we suggest that it is due to sustained mild iron-reducing conditions that dissolved the most labile aeolian-derived iron, which favoured continued magnetotactic bacterial activity without being strong enough to dissolve the less reactive magnetite and haematite. Enhanced aeolian haematite abundances at the beginning of the PETM indicate drier conditions on the neighbouring Antarctic continent at those times. Our results provide evidence that iron fertilisation by aeolian dust was the main limiting factor that conditioned proliferation of magnetotactic bacteria in the deep sea at the southern Kerguelen Plateau, with the exception of two short periods of rapidly changing palaeoenvironmental conditions at the onset and termination of the PETM. Increased iron supply from aeolian dust, that enhanced oceanic primary productivity and subsequent delivery of organic carbon to the seafloor, along with mild iron-reducing diagenetic conditions, seem to have been necessary to provide the iron needed for magnetite biomineralization by magnetotactic bacteria to drive their marked increase in abundance in the studied PETM record from southern Kerguelen Plateau. Our analyses of a deep-sea PETM record from Hole 1051B at Blake Nose (Atlantic Ocean) failed to identify magnetofossils despite evidence for the occurrence of magnetite and haematite of probable aeolian origin. Contrasting magnetic properties at these PETM ... |
format |
Article in Journal/Newspaper |
author |
Larrasoaña, Juan C. Roberts, Andrew P. Liao, Chang Schellenberg, Stephen A. Fitz Gerald, John D. Norris, Richard D. Zachos, James C. |
author_facet |
Larrasoaña, Juan C. Roberts, Andrew P. Liao, Chang Schellenberg, Stephen A. Fitz Gerald, John D. Norris, Richard D. Zachos, James C. |
author_sort |
Larrasoaña, Juan C. |
title |
Magnetotactic bacterial response to Antarctic dust supply during the Palaeocene–Eocene thermal maximum |
title_short |
Magnetotactic bacterial response to Antarctic dust supply during the Palaeocene–Eocene thermal maximum |
title_full |
Magnetotactic bacterial response to Antarctic dust supply during the Palaeocene–Eocene thermal maximum |
title_fullStr |
Magnetotactic bacterial response to Antarctic dust supply during the Palaeocene–Eocene thermal maximum |
title_full_unstemmed |
Magnetotactic bacterial response to Antarctic dust supply during the Palaeocene–Eocene thermal maximum |
title_sort |
magnetotactic bacterial response to antarctic dust supply during the palaeocene–eocene thermal maximum |
publisher |
Elsevier |
publishDate |
2012 |
url |
http://hdl.handle.net/10261/276961 https://doi.org/10.1016/j.epsl.2012.04.003 |
op_coverage |
Meseta Kerguelen, Océano Índico |
geographic |
Antarctic Kerguelen Southern Ocean |
geographic_facet |
Antarctic Kerguelen Southern Ocean |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
https://www.sciencedirect.com/science/article/abs/pii/S0012821X12001707 Earth and Planetary Science Letters, vol.333–334, 122-133 1385-013X http://hdl.handle.net/10261/276961 https://doi.org/10.1016/j.epsl.2012.04.003 |
op_rights |
open |
op_doi |
https://doi.org/10.1016/j.epsl.2012.04.003 |
container_title |
Earth and Planetary Science Letters |
container_volume |
333-334 |
container_start_page |
122 |
op_container_end_page |
133 |
_version_ |
1790593202386894848 |