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Enhanced primary productivity and magnetotactic bacterial production in response to middle Eocene warming in the Neo-Tethys Ocean

Enhanced primary productivity and magnetotactic bacterial production in response to middle Eocene warming in the Neo-Tethys Ocean
Enhanced primary productivity and magnetotactic bacterial production in response to middle Eocene warming in the Neo-Tethys Ocean
Earth's climate experienced a warming event known as the Middle Eocene Climatic Optimum (MECO) at ~ 40 Ma, which was an abrupt reversal of a long-term Eocene cooling trend. This event is characterized in the deep Southern, Atlantic, Pacific and Indian Oceans by a distinct negative δ18O excursion over 500 kyr. We report results of high-resolution paleontological, geochemical, and rock magnetic investigations of the Neo-Tethyan Monte Cagnero (MCA) section (northeastern Apennines, Italy), which can be correlated on the basis of magneto- and biostratigraphic results to the MECO event recorded in deep-sea sections. In the MCA section, an interval with a relative increase in eutrophic nannofossil taxa (and decreased abundances of oligotrophic taxa) spans the culmination of the MECO warming and its aftermath and coincides with a positive carbon isotope excursion, and a peak in magnetite and hematite/goethite concentration. The magnetite peak reflects the appearance of putative magnetofossils, while the hematite/goethite apex is attributed to an enhanced detrital mineral contribution, likely as aeolian dust transported from the continent adjacent to the Neo-Tethys Ocean during a drier, more seasonal climate during the peak MECO warming. Based on our new geochemical, paleontological and magnetic records, the MECO warming peak and its immediate aftermath are interpreted as a period of high primary productivity. Sea-surface iron fertilization is inferred to have stimulated high phytoplankton productivity, increasing organic carbon export to the seafloor and promoting enhanced biomineralization of magnetotactic bacteria, which are preserved as putative magnetofossils during the warmest periods of the MECO event in the MCA section. Together with previous studies, our work reinforces the connection between hyperthermal climatic events and the occurrence (or increased abundance) of putative magnetofossils in the sedimentary record.
Paleoproductivity, MECO, Putative magnetofossils, Monte Cagnero, Italy
0031-0182
32-45
Savian, Jairo F.
db555433-9c1f-4434-b8e6-a898d5ca6f37
Jovane, Luigi
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Frontalini, Fabrizio
0564bc17-ed9d-40e9-8894-ed916f3a7154
Trindade, Ricardo I.F.
e5c894a5-3c06-4363-808a-dc2ab0f02ec5
Coccioni, Rodolfo
ab9b9b8f-13b3-41a8-9fcd-b841f9ab55e1
Bohaty, Steven M.
af9dbe78-8b9f-44f2-ba1d-20795837d2d1
Wilson, Paul A.
f940a9f0-fa5a-4a64-9061-f0794bfbf7c6
Florindo, Fabio
5953170b-79f7-431e-9e08-824a47e0fbd5
Roberts, Andrew P.
4f062491-5408-4edb-8dd1-140c6a42e93f
Catanzariti, Rita
8000c645-5e5f-45d5-9544-300763f78552
Iacoviello, Francesco
1f4aeca4-5a22-4d14-9901-067669ca127b
Savian, Jairo F.
db555433-9c1f-4434-b8e6-a898d5ca6f37
Jovane, Luigi
7e165ffb-8e06-4ac1-9c47-d3edf3e0ddd8
Frontalini, Fabrizio
0564bc17-ed9d-40e9-8894-ed916f3a7154
Trindade, Ricardo I.F.
e5c894a5-3c06-4363-808a-dc2ab0f02ec5
Coccioni, Rodolfo
ab9b9b8f-13b3-41a8-9fcd-b841f9ab55e1
Bohaty, Steven M.
af9dbe78-8b9f-44f2-ba1d-20795837d2d1
Wilson, Paul A.
f940a9f0-fa5a-4a64-9061-f0794bfbf7c6
Florindo, Fabio
5953170b-79f7-431e-9e08-824a47e0fbd5
Roberts, Andrew P.
4f062491-5408-4edb-8dd1-140c6a42e93f
Catanzariti, Rita
8000c645-5e5f-45d5-9544-300763f78552
Iacoviello, Francesco
1f4aeca4-5a22-4d14-9901-067669ca127b

Savian, Jairo F., Jovane, Luigi, Frontalini, Fabrizio, Trindade, Ricardo I.F., Coccioni, Rodolfo, Bohaty, Steven M., Wilson, Paul A., Florindo, Fabio, Roberts, Andrew P., Catanzariti, Rita and Iacoviello, Francesco (2014) Enhanced primary productivity and magnetotactic bacterial production in response to middle Eocene warming in the Neo-Tethys Ocean. Palaeogeography Palaeoclimatology Palaeoecology, 414, 32-45. (doi:10.1016/j.palaeo.2014.08.009).

Record type: Article

Abstract

Earth's climate experienced a warming event known as the Middle Eocene Climatic Optimum (MECO) at ~ 40 Ma, which was an abrupt reversal of a long-term Eocene cooling trend. This event is characterized in the deep Southern, Atlantic, Pacific and Indian Oceans by a distinct negative δ18O excursion over 500 kyr. We report results of high-resolution paleontological, geochemical, and rock magnetic investigations of the Neo-Tethyan Monte Cagnero (MCA) section (northeastern Apennines, Italy), which can be correlated on the basis of magneto- and biostratigraphic results to the MECO event recorded in deep-sea sections. In the MCA section, an interval with a relative increase in eutrophic nannofossil taxa (and decreased abundances of oligotrophic taxa) spans the culmination of the MECO warming and its aftermath and coincides with a positive carbon isotope excursion, and a peak in magnetite and hematite/goethite concentration. The magnetite peak reflects the appearance of putative magnetofossils, while the hematite/goethite apex is attributed to an enhanced detrital mineral contribution, likely as aeolian dust transported from the continent adjacent to the Neo-Tethys Ocean during a drier, more seasonal climate during the peak MECO warming. Based on our new geochemical, paleontological and magnetic records, the MECO warming peak and its immediate aftermath are interpreted as a period of high primary productivity. Sea-surface iron fertilization is inferred to have stimulated high phytoplankton productivity, increasing organic carbon export to the seafloor and promoting enhanced biomineralization of magnetotactic bacteria, which are preserved as putative magnetofossils during the warmest periods of the MECO event in the MCA section. Together with previous studies, our work reinforces the connection between hyperthermal climatic events and the occurrence (or increased abundance) of putative magnetofossils in the sedimentary record.

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More information

Published date: 15 November 2014
Keywords: Paleoproductivity, MECO, Putative magnetofossils, Monte Cagnero, Italy
Organisations: Paleooceanography & Palaeoclimate

Identifiers

Local EPrints ID: 371890
URI: http://eprints.soton.ac.uk/id/eprint/371890
ISSN: 0031-0182
PURE UUID: 6c1b25b4-6bff-4b96-b1cf-ece7cbe0ab19
ORCID for Steven M. Bohaty: ORCID iD orcid.org/0000-0002-1193-7398
ORCID for Paul A. Wilson: ORCID iD orcid.org/0000-0001-6425-8906

Catalogue record

Date deposited: 18 Nov 2014 10:32
Last modified: 15 Mar 2024 03:27

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Contributors

Author: Jairo F. Savian
Author: Luigi Jovane
Author: Fabrizio Frontalini
Author: Ricardo I.F. Trindade
Author: Rodolfo Coccioni
Author: Paul A. Wilson ORCID iD
Author: Fabio Florindo
Author: Andrew P. Roberts
Author: Rita Catanzariti
Author: Francesco Iacoviello

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