Roberts, Andrew P; Florindo, Fabio; Villa, Giuliana; Chang, Liao; Jovane, Luigi; Bohaty, Steven M; Larrasoaña, Juan C; Heslop, David; Fitz Gerald, John D (2011): Magnetic analyses of ODP Hole 119-738B sediments [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.788624, Supplement to: Roberts, AP et al. (2011): Magnetotactic bacterial abundance in pelagic marine environments is limited by organic carbon flux and availability of dissolved iron. Earth and Planetary Science Letters, 310(3-4), 441-452, https://doi.org/10.1016/j.epsl.2011.08.011
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Abstract:
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.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Latitude: -62.709000 * Longitude: 82.787800
Date/Time Start: 1988-01-10T16:30:00 * Date/Time End: 1988-01-11T18:45:00
Event(s):
119-738B * Latitude: -62.709000 * Longitude: 82.787800 * Date/Time Start: 1988-01-10T16:30:00 * Date/Time End: 1988-01-11T18:45:00 * Elevation: -2263.0 m * Penetration: 214.3 m * Recovery: 170.85 m * Location: Indian Ocean * Campaign: Leg119 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 24 cores; 214.3 m cored; 0 m drilled; 79.7 % recovery
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
2 datasets
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Datasets listed in this publication series
- Roberts, AP; Florindo, F; Villa, G et al. (2011): (Table 2) Parameters associated with components identified from IRM unmixing analysist of ODP Hole 119-738B sediments. https://doi.org/10.1594/PANGAEA.788621
- Roberts, AP; Florindo, F; Villa, G et al. (2011): (Table 1) Measured hysteresis and electron paramagnetic resonance parameters for ODP Hole 119-738B sediments. https://doi.org/10.1594/PANGAEA.788617