Magnetotactic bacterial abundance in pelagic marine environments is limited by organic carbon flux and availability of dissolved iron
Magnetotactic bacteria intracellularly biomineralize magnetite of an ideal grain size for recording palaeomagnetic signals. However, bacterial magnetite has only been reported in a few pre-Quaternary records because progressive burial into anoxic diagenetic environments causes its dissolution. Deep-...
Published in: | Earth and Planetary Science Letters |
---|---|
Main Authors: | , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Elsevier
|
Subjects: | |
Online Access: | http://hdl.handle.net/1885/51485 https://doi.org/10.1016/j.epsl.2011.08.011 https://openresearch-repository.anu.edu.au/bitstream/1885/51485/5/2011_Roberts_et_al.pdf.jpg https://openresearch-repository.anu.edu.au/bitstream/1885/51485/7/01_Roberts_Magnetotactic_bacterial_2011.pdf.jpg |
id |
ftanucanberra:oai:openresearch-repository.anu.edu.au:1885/51485 |
---|---|
record_format |
openpolar |
spelling |
ftanucanberra:oai:openresearch-repository.anu.edu.au:1885/51485 2024-01-14T10:10:52+01:00 Magnetotactic bacterial abundance in pelagic marine environments is limited by organic carbon flux and availability of dissolved iron Roberts, Andrew Florindo, Fabio Villa, Giuliana Chang, Liao Jovane, Luigi Bohaty, S Larrasoaña, Juan C. Heslop, David Fitz Gerald, John http://hdl.handle.net/1885/51485 https://doi.org/10.1016/j.epsl.2011.08.011 https://openresearch-repository.anu.edu.au/bitstream/1885/51485/5/2011_Roberts_et_al.pdf.jpg https://openresearch-repository.anu.edu.au/bitstream/1885/51485/7/01_Roberts_Magnetotactic_bacterial_2011.pdf.jpg unknown Elsevier 0012-821X http://hdl.handle.net/1885/51485 doi:10.1016/j.epsl.2011.08.011 https://openresearch-repository.anu.edu.au/bitstream/1885/51485/5/2011_Roberts_et_al.pdf.jpg https://openresearch-repository.anu.edu.au/bitstream/1885/51485/7/01_Roberts_Magnetotactic_bacterial_2011.pdf.jpg Earth and Planetary Science Letters Keywords: Aeolian dusts Bacterial abundance Bacterial population Diagenetics Dissolved iron Grain size Iron fertilization Iron reduction Kerguelen plateau Late Eocene Low rates Magnetofossils Magnetotactic Bacteria Marine environment Optimal environme Iron Magnetite Organic carbon Productivity Journal article ftanucanberra https://doi.org/10.1016/j.epsl.2011.08.011 2023-12-15T09:37:03Z Magnetotactic bacteria intracellularly biomineralize magnetite of an ideal grain size for recording palaeomagnetic signals. However, bacterial magnetite has only been reported in a few pre-Quaternary records because progressive burial into anoxic diagenetic environments causes its dissolution. Deep-sea carbonate sequences provide optimal environments for preserving bacterial magnetite due to low rates of organic carbon burial and expanded pore-water redox zonations. Such sequences often do not become anoxic for tens to hundreds of metres below the seafloor. Nevertheless, the biogeochemical factors that control magnetotactic bacterial populations in such settings are not well known. We document the preservation of bacterial magnetite, which dominates the palaeomagnetic signal throughout Eocene pelagic carbonates from the southern Kerguelen Plateau, Southern Ocean. We provide evidence that iron fertilization, associated with increased aeolian dust flux, resulted in surface water eutrophication in the late Eocene that controlled bacterial magnetite abundance via export of organic carbon to the seafloor. Increased flux of aeolian iron-bearing phases also delivered iron to the seafloor, some of which became bioavailable through iron reduction. Our results suggest that magnetotactic bacterial populations in pelagic settings depend crucially on particulate iron and organic carbon delivery to the seafloor. Article in Journal/Newspaper Southern Ocean Australian National University: ANU Digital Collections Southern Ocean Kerguelen Earth and Planetary Science Letters 310 3-4 441 452 |
institution |
Open Polar |
collection |
Australian National University: ANU Digital Collections |
op_collection_id |
ftanucanberra |
language |
unknown |
topic |
Keywords: Aeolian dusts Bacterial abundance Bacterial population Diagenetics Dissolved iron Grain size Iron fertilization Iron reduction Kerguelen plateau Late Eocene Low rates Magnetofossils Magnetotactic Bacteria Marine environment Optimal environme Iron Magnetite Organic carbon Productivity |
spellingShingle |
Keywords: Aeolian dusts Bacterial abundance Bacterial population Diagenetics Dissolved iron Grain size Iron fertilization Iron reduction Kerguelen plateau Late Eocene Low rates Magnetofossils Magnetotactic Bacteria Marine environment Optimal environme Iron Magnetite Organic carbon Productivity Roberts, Andrew Florindo, Fabio Villa, Giuliana Chang, Liao Jovane, Luigi Bohaty, S Larrasoaña, Juan C. Heslop, David Fitz Gerald, John Magnetotactic bacterial abundance in pelagic marine environments is limited by organic carbon flux and availability of dissolved iron |
topic_facet |
Keywords: Aeolian dusts Bacterial abundance Bacterial population Diagenetics Dissolved iron Grain size Iron fertilization Iron reduction Kerguelen plateau Late Eocene Low rates Magnetofossils Magnetotactic Bacteria Marine environment Optimal environme Iron Magnetite Organic carbon Productivity |
description |
Magnetotactic bacteria intracellularly biomineralize magnetite of an ideal grain size for recording palaeomagnetic signals. However, bacterial magnetite has only been reported in a few pre-Quaternary records because progressive burial into anoxic diagenetic environments causes its dissolution. Deep-sea carbonate sequences provide optimal environments for preserving bacterial magnetite due to low rates of organic carbon burial and expanded pore-water redox zonations. Such sequences often do not become anoxic for tens to hundreds of metres below the seafloor. Nevertheless, the biogeochemical factors that control magnetotactic bacterial populations in such settings are not well known. We document the preservation of bacterial magnetite, which dominates the palaeomagnetic signal throughout Eocene pelagic carbonates from the southern Kerguelen Plateau, Southern Ocean. We provide evidence that iron fertilization, associated with increased aeolian dust flux, resulted in surface water eutrophication in the late Eocene that controlled bacterial magnetite abundance via export of organic carbon to the seafloor. Increased flux of aeolian iron-bearing phases also delivered iron to the seafloor, some of which became bioavailable through iron reduction. Our results suggest that magnetotactic bacterial populations in pelagic settings depend crucially on particulate iron and organic carbon delivery to the seafloor. |
format |
Article in Journal/Newspaper |
author |
Roberts, Andrew Florindo, Fabio Villa, Giuliana Chang, Liao Jovane, Luigi Bohaty, S Larrasoaña, Juan C. Heslop, David Fitz Gerald, John |
author_facet |
Roberts, Andrew Florindo, Fabio Villa, Giuliana Chang, Liao Jovane, Luigi Bohaty, S Larrasoaña, Juan C. Heslop, David Fitz Gerald, John |
author_sort |
Roberts, Andrew |
title |
Magnetotactic bacterial abundance in pelagic marine environments is limited by organic carbon flux and availability of dissolved iron |
title_short |
Magnetotactic bacterial abundance in pelagic marine environments is limited by organic carbon flux and availability of dissolved iron |
title_full |
Magnetotactic bacterial abundance in pelagic marine environments is limited by organic carbon flux and availability of dissolved iron |
title_fullStr |
Magnetotactic bacterial abundance in pelagic marine environments is limited by organic carbon flux and availability of dissolved iron |
title_full_unstemmed |
Magnetotactic bacterial abundance in pelagic marine environments is limited by organic carbon flux and availability of dissolved iron |
title_sort |
magnetotactic bacterial abundance in pelagic marine environments is limited by organic carbon flux and availability of dissolved iron |
publisher |
Elsevier |
url |
http://hdl.handle.net/1885/51485 https://doi.org/10.1016/j.epsl.2011.08.011 https://openresearch-repository.anu.edu.au/bitstream/1885/51485/5/2011_Roberts_et_al.pdf.jpg https://openresearch-repository.anu.edu.au/bitstream/1885/51485/7/01_Roberts_Magnetotactic_bacterial_2011.pdf.jpg |
geographic |
Southern Ocean Kerguelen |
geographic_facet |
Southern Ocean Kerguelen |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Earth and Planetary Science Letters |
op_relation |
0012-821X http://hdl.handle.net/1885/51485 doi:10.1016/j.epsl.2011.08.011 https://openresearch-repository.anu.edu.au/bitstream/1885/51485/5/2011_Roberts_et_al.pdf.jpg https://openresearch-repository.anu.edu.au/bitstream/1885/51485/7/01_Roberts_Magnetotactic_bacterial_2011.pdf.jpg |
op_doi |
https://doi.org/10.1016/j.epsl.2011.08.011 |
container_title |
Earth and Planetary Science Letters |
container_volume |
310 |
container_issue |
3-4 |
container_start_page |
441 |
op_container_end_page |
452 |
_version_ |
1788065726368579584 |