URLhttps://www.bco-dmo.org/dataset/713673
Download URLhttps://www.bco-dmo.org/dataset/713673/data/download
Media Typetext/tab-separated-values
CreatedAugust 24, 2017
ModifiedAugust 24, 2017
StatePreliminary and in progress
Brief DescriptionSiderophore-enhanced olivine dissolution experiments

Acquisition Description

Experiments were conducted by adding a known mass of olivine to a TRIS/HCl buffered solution (10 mM; pH approximately 7.5) in a plastic bottle. Deferoxamine B purchased from Sigma Aldrich was added to experiments after being dissolved in de-ionized water. The bottles were placed into a heated shaking table (200 rpm) and incubated at 30 degrees celsius. Periodically, solution samples were removed by pipette and preserved by acidification with one uL of concentrated HCl per mL of sample solution. Solutions were analyzed for Mg, Si, and Fe concentrations.

Processing Description

Linear calibration against synthetic, matrix-matched standards

BCO-DMO Processing Notes:
- modified parameter names to conform with BCO-DMO naming conventions.

Instruments

Agilent 4100 MP-AES [Spectrometer]
Details
Instance Description (Agilent 4100 MP-AES)

Solutions were analyzed for Mg, Si, and Fe concentrations using Agilent 4100 Microwave Plasma Atomic Emission Spectrometer (MP-AES).

A spectrometer is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum.

Parameters

elapsed_time [time_elapsed]
Details
elapsed_time
time elapsed of experiment
Elapsed time. Typically found in CTD profile data. Units can be seconds, minutes, etc.
initial_DFOB_concentration [unknown]
Details
initial_DFOB_concentration
Deferoxamine B initial concentration
association with a community-wide standard parameter is not yet defined
Si_released [Si]
Details
Si_released
concentration of Si released

Si (Silicon) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.

Fe_released [Fe]
Details
Fe_released
concentration of Fe released
Fe (Iron) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Mg_released [Mg]
Details
Mg_released
concentration of Mg released

Mg (magnesium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.

Dataset Maintainers

NameAffiliationContact
Mark A. TorresUniversity of Southern California (USC)
A. Joshua WestUniversity of Southern California (USC)
Mark A. TorresUniversity of Southern California (USC)
Mathew BiddleWoods Hole Oceanographic Institution (WHOI BCO-DMO)

BCO-DMO Project Info

Project TitleIdentifying the Mechanisms and Limits of the Microbial Enhancement of Olivine Dissolution
AcronymMicrobial Olivine Dissolution
URLhttps://www.bco-dmo.org/project/713155
CreatedAugust 18, 2017
ModifiedAugust 18, 2017
Project Description

Project abstract from C-DEBI:
The project focused on the efficacy by which microorganisms can obtain nutrient Fe from silicate minerals. Silicate minerals are a particularly abundant mineral phase in the oceanic crust and thus the bio-availability of silicate-bound nutrients has important implications for microbial activity in the deep subseafloor (C-DEBI theme 1) and the limits to microbial life (C-DEBI theme 3). The specific goal of this project was to quantitatively determine how metal-binding organic compounds (siderophores) produced by microorganisms under Fe-limited conditions affect the rate of Fe-silicate mineral dissolution using laboratory experiments. The exact effect of microbial activity on Fe-silicate mineral dissolution has previously been hard to discern due to the complicating effects of feedbacks associated with microbial growth, siderophore production, and mineral dissolution rates. To limit the effects of these feedbacks, my experimental design used purified microbial siderophores and a silicate mineral (olivine) that dissolves at a rate that is relatively insensitive to the accumulation of its constituent ions in solution. My results showed that sub-millimolar siderophore concentrations lead to an order of magnitude increase in olivine dissolution rates. The accelerating effect of siderophores was linked to the removal of an inhibiting surface Fe-oxide coating that forms during the reaction of olivine at circum-neutral pH in the presence of O2. By combining the experimental results with a numerical model of the relevant biological feedbacks, this work further constrained the maximum extent to which microbial activity may affect silicate mineral dissolution rates under conditions of Fe-limitation. The results of this study are presently under review for publication in Geobiology.

This work was supported through a C-DEBI graduate fellowship.

Project Maintainers
NameAffiliationRoleContact
Mark A. TorresUniversity of Southern California (USC)Principal Investigator
A. Joshua WestUniversity of Southern California (USC)Co-Principal Investigator
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