The efficient long-term inhibition of forsterite dissolution by common soil bacteria and fungi at earth surface conditions
The efficient long-term inhibition of forsterite dissolution by common soil bacteria and fungi at earth surface conditions
San Carlos forsterite was dissolved in initially pure H2O in a batch reactor in contact with the atmosphere for five years. The reactive fluid aqueous pH remained relatively stable at pH 6.7 throughout the experiment. Aqueous Mg concentration maximized after approximately two years time at 3x10-5 mol/kg, whereas aqueous Si concentrations increased continuously with time, reaching 2x10-5 mol/kg after 5 years. Element release rates closely matched those determined on this same forsterite sample during short-term abiotic open system experiments for the first 10 days, then slowed substantially such that the Mg and Si release rates are approximately an order of magnitude slower than that calculated from the short-term abiotic experiments. Post-experiment analysis reveals that secondary hematite, a substantial biotic community, and minor amorphous silica formed on the dissolving forsterite during the experiment. The biotic community included bacteria, dominated by Rhizobiales (Alphaproteobacteria), and fungi, dominated by Trichocomaceae, that grew in a carbon and nutrient-limited media on the dissolving forsterite. The Mg isotope composition of the reactive fluid was near constant after 2 years but 0.25‰ heavier in ?26Mg than the dissolving forsterite. Together these results suggest long-term forsterite dissolution in natural Earth surface systems maybe substantially slower that estimated from short-term abiotic experiments due to the growth of biotic communities on their surfaces.
222-235
Oelkers, Eric H.
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Benning, Liane G.
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Lutz, Stefanie
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Mavromatis, Vasileios
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Pearce, Christopher R.
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Plümper, Oliver
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1 November 2015
Oelkers, Eric H.
3cf51d71-be44-4bed-803e-3b240bdb147b
Benning, Liane G.
9ec5c1b9-f878-4194-b011-7548040f83b4
Lutz, Stefanie
cdb611ab-a6e2-436f-9fbf-8afa3ff94bcf
Mavromatis, Vasileios
b15603d0-512c-48f1-ab49-10b5294ab4df
Pearce, Christopher R.
3d683112-72dc-444f-ae06-da9c571d799a
Plümper, Oliver
de60c14d-df6f-47c5-a0a3-933d175caa7b
Oelkers, Eric H., Benning, Liane G., Lutz, Stefanie, Mavromatis, Vasileios, Pearce, Christopher R. and Plümper, Oliver
(2015)
The efficient long-term inhibition of forsterite dissolution by common soil bacteria and fungi at earth surface conditions.
Geochimica et Cosmochimica Acta, 168, .
(doi:10.1016/j.gca.2015.06.004).
Abstract
San Carlos forsterite was dissolved in initially pure H2O in a batch reactor in contact with the atmosphere for five years. The reactive fluid aqueous pH remained relatively stable at pH 6.7 throughout the experiment. Aqueous Mg concentration maximized after approximately two years time at 3x10-5 mol/kg, whereas aqueous Si concentrations increased continuously with time, reaching 2x10-5 mol/kg after 5 years. Element release rates closely matched those determined on this same forsterite sample during short-term abiotic open system experiments for the first 10 days, then slowed substantially such that the Mg and Si release rates are approximately an order of magnitude slower than that calculated from the short-term abiotic experiments. Post-experiment analysis reveals that secondary hematite, a substantial biotic community, and minor amorphous silica formed on the dissolving forsterite during the experiment. The biotic community included bacteria, dominated by Rhizobiales (Alphaproteobacteria), and fungi, dominated by Trichocomaceae, that grew in a carbon and nutrient-limited media on the dissolving forsterite. The Mg isotope composition of the reactive fluid was near constant after 2 years but 0.25‰ heavier in ?26Mg than the dissolving forsterite. Together these results suggest long-term forsterite dissolution in natural Earth surface systems maybe substantially slower that estimated from short-term abiotic experiments due to the growth of biotic communities on their surfaces.
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Accepted/In Press date: June 2015
Published date: 1 November 2015
Organisations:
Marine Geoscience
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Local EPrints ID: 378078
URI: http://eprints.soton.ac.uk/id/eprint/378078
ISSN: 0016-7037
PURE UUID: b84e199a-a9b9-4153-ba5c-5ac17055fe33
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Date deposited: 16 Jun 2015 09:11
Last modified: 14 Mar 2024 20:16
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Contributors
Author:
Eric H. Oelkers
Author:
Liane G. Benning
Author:
Stefanie Lutz
Author:
Vasileios Mavromatis
Author:
Christopher R. Pearce
Author:
Oliver Plümper
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