URLhttps://www.bco-dmo.org/dataset/806957
Download URLhttps://www.bco-dmo.org/dataset/806957/data/download
Media Typetext/tab-separated-values
CreatedMarch 25, 2020
ModifiedApril 9, 2020
StateFinal no updates expected
Brief DescriptionTable 2

Acquisition Description

X-ray diffraction (XRD)

Powdered samples were examined for mineral presence using a Rigaku Ultima III X-ray Diffraction (XRD) System at the Institute of Imaging and Analytical Technologies (i2AT) at Mississippi State University. These analyses were conducted at 40 kV and 40 mA.

Elemental analysis of experimental aragonite crystals and experimental fluids with ICP-MS

Crystals were dissolved and solutions were analyzed by ICP-MS. Experimental fluids were also analyzed with ICP-MS, as well. Analyses were conducted on an Agilent 7900 quadrupole ICP-MS equipped with a glass nebulizer at the University of Rochester (Rochester, NY). Prior to analysis, fluid samples were diluted with 2% trace metal grade HNO3 (Fisher) in the volume proportion of 1:100. Aragonite crystals were dissolved in HNO3 in the mass proportion of 1:1000. Experimental fluid samples were analyzed using a 5-point calibration curve (one blank and four standards). Seawater standards were prepared by diluting a seawater certificate reference material (CRM-SW; High-Purity Standards) to a final concentration of ~300, 200, 150, and 80 ppm. Experimental crystals were analyzed using a 5-point calibration curve (one blank and four standards). Calcium carbonate standards were prepared by dissolving and diluting the original MACS-3 powder to a final concentration of ~111, 55, 27, and 11 ppm. Because S concentration was not reported in the certificate of analysis provided by the USGS, we added a small amount of sulfur single element standard (Inorganic Ventures) to a final concentration of ~1.5, 0.75, 0.375, and 0.150 ppm, in each MACS-3 standard we prepared. Samples, blanks, and standards were also spiked with 2 ppb indium, which was used as the internal standard to check for possible instrumental drift during each analytical session.

The instrument was tuned at the beginning of each analytical session (two analytical sessions in two consecutive days). 24Mg, 34S, 43Ca, 88Sr, 138Ba, and 238U were analyzed.  Integration times were the following: 0.3 s for 24Mg; 0.12 s for 43Ca, 88Sr, and 138Ba; 0.99 s for 238U. The calibration curve was run before analyzing each set of samples. For each element analyzed, the correlation among standards was 0.9923 or better. Elements were identified using three peaks. Each analysis included three replicates, with 100 sweeps/replicate. The carrier gas (argon) flow was set at 1.15 L/min. In addition, we used helium flow of 4.2 milliliters per minute in the collision reaction cell in the ICP-MS to minimize oxide interference. At the end of each tuning, oxides and doubly-charged ion interferences were below 0.8% and 1.4%, respectively. Data were computed automatically during the run using the Agilent Mass Hunter 4.1 workstation software v. C.01.01.

Results

XRD spectra identified the presence of aragonite and monohydrocalcite (Table 2). Only aragonite crystallized at intermediate pressure (110 bars). Calculations of fluid carbonate chemistry were conducted with a CO2SYS spreadsheet (Lewis and Wallace, 1998)  and presented in Table 1. There, measured pH and total alkalinity (TA) were used to calculate the concentration of CO32-, which together with Ca2+ is necessary to calculate fluid saturation states with respect to aragonite (Omega-Ar). Precipitation started at saturation state, which exceeds that of artificial seawater (ASW) by the factor of ~25. Over the course of the experiments, Omega-Ar decreased back to 2, i.e. Omega-Ar value of ASW prior to the addition of Na2CO3. Table 2 contains E/Ca of experimental products (solids and liquids) as well as the Doener-Hoskins apparent partition coefficients between solid and fluid (KE). Fluid composition changed during individual experiments, and therefore, values of KE were calculated using the Doener-Hoskins relationship:

       KE= log(1+ mE^aragonite /mE^fluid) / log(1+ mCa^aragonite /mCa^fluid)    (1)

where m^aragonite is the total number of moles of element (i.e., Mg, S, Sr, Ba, or U) or Ca in the final precipitate, and m^fluid is the total number of moles of element or Ca in the final fluid (Doerner and Hoskins, 1925).

Software products used:
XRD: Jade and Microsoft Excel
ICP-MS: Agilent Mass Hunter 4.1 workstation software v. C.01.01 and Microsoft Excel

Processing Description

BCO-DMO Data Manager Processing Notes:
- added a conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- blank values in this dataset are displayed as "nd" for "no data."  nd is the default missing data identifier in the BCO-DMO system.
- reformatted table so each column represent only one parameter
- removed quotes, replaced commas with semicolons

 

Instruments

high-pressure apparatus [unknown]
Details
Instance Description (high-pressure apparatus)

Custom designed pressure chamber used to simulate the high-pressure conditions at the seafloor for this set of experiments (designed at Rensselaer Polytech Institute, Department of Earth and Environmental Sciences).

No relevant match in BCO-DMO instrument vocabulary.

Agilent 7900 quadrupole ICP-MS equipped with a glass nebulizer at the University of Rochester (Rochester, NY) [Inductively Coupled Plasma Optical Emission Spectrometer]
Details

Also referred to as an Inductively coupled plasma atomic emission spectroscope (ICP-AES). These instruments pass nebulised samples into an inductively-coupled gas plasma (8-10000 K) where they are atomised and excited. The de-excitation optical emissions at characteristic wavelengths are spectroscopically analysed. It is often used in the detection of trace metals.

Rigaku Ultima III X-ray Diffraction (XRD) System at the Institute of Imaging and Analytical Technologies (i2AT) [X-ray diffractometer]
Details
Instance Description (Rigaku Ultima III X-ray Diffraction (XRD) System at the Institute of Imaging and Analytical Technologies (i2AT))

Located at  at Mississippi State University

Instruments that identify crystalline solids by measuring the characteristic spaces between layers of atoms or molecules in a crystal.

Parameters

analysis [unknown]
Details
analysis

The type of analysis: solids; fluids; or KE (Doener-Hoskins partition coefficients between solid and fluid)

association with a community-wide standard parameter is not yet defined
run [exp_id]
Details
run
experimental run identifier
Experiment Id
press [pressure]
Details
press
pressure
water pressure at measurement; depth reported as pressure; positive number increasing with water depth
minerals [unknown]
Details
minerals
minerals identified with X-ray diffraction technique: aragonite; monoclinic carbonate (CaCO3-II)
association with a community-wide standard parameter is not yet defined
Mg_Ca [unknown]
Details
Mg_Ca
magnesium to calcium ratio in carbonate crystals (solids) or in fluid at end of experiment
association with a community-wide standard parameter is not yet defined
Mg_Ca_2sd [unknown]
Details
Mg_Ca_2sd
two standard deviations from the mean of magnesium to calcium ratio
association with a community-wide standard parameter is not yet defined
S_Ca [unknown]
Details
S_Ca
sulfur to calcium ratio in carbonate crystals (solids) or in fluid at end of experiment
association with a community-wide standard parameter is not yet defined
S_Ca_2sd [unknown]
Details
S_Ca_2sd
two standard deviations from the mean of sulfur to calcium ratio
association with a community-wide standard parameter is not yet defined
Sr_Ca [unknown]
Details
Sr_Ca
strontium to calcium ratio in carbonate crystals (solids) or in fluid at end of experiment
association with a community-wide standard parameter is not yet defined
Sr_Ca_2sd [unknown]
Details
Sr_Ca_2sd
two standard deviations from the mean of strontium to calcium ratio
association with a community-wide standard parameter is not yet defined
Ba_Ca [unknown]
Details
Ba_Ca
barium to calcium ratio in carbonate crystals (solids) or in fluid at end of experiment
association with a community-wide standard parameter is not yet defined
Ba_Ca_2sd [unknown]
Details
Ba_Ca_2sd
two standard deviations from the mean of barium to calcium ratio
association with a community-wide standard parameter is not yet defined
KMg [unknown]
Details
KMg
Doener-Hoskins partition coefficients of magnesium multiplied by 1000
association with a community-wide standard parameter is not yet defined
KMg_2sd [unknown]
Details
KMg_2sd
two standard deviations from the mean of Doener-Hoskins partition coefficients of magnesium multiplied by 1000
association with a community-wide standard parameter is not yet defined
KS [unknown]
Details
KS
Doener-Hoskins partition coefficients of sulfur multiplied by 1000
association with a community-wide standard parameter is not yet defined
KS_2sd [unknown]
Details
KS_2sd
two standard deviations from the mean of Doener-Hoskins partition coefficients of sulfur multiplied by 1000
association with a community-wide standard parameter is not yet defined
KSr [unknown]
Details
KSr
Doener-Hoskins partition coefficients of strontium
association with a community-wide standard parameter is not yet defined
KSr_2sd [unknown]
Details
KSr_2sd
two standard deviations from the mean of Doener-Hoskins partition coefficients of strontium
association with a community-wide standard parameter is not yet defined
KBa [unknown]
Details
KBa
Doener-Hoskins partition coefficients of barium
association with a community-wide standard parameter is not yet defined
Kba_2sd [unknown]
Details
Kba_2sd
two standard deviations from the mean of Doener-Hoskins partition coefficients of barium
association with a community-wide standard parameter is not yet defined

Dataset Maintainers

NameAffiliationContact
Rinat GabitovMississippi State University (MSU)
Karyn L. RogersRensselaer Polytechnic Institute (RPI)
Chiara BorrelliUniversity of Rochester
Nancy CopleyWoods Hole Oceanographic Institution (WHOI BCO-DMO)

BCO-DMO Project Info

Project TitleBiologically induced methane oxidation and precipitation of carbonate minerals: An experimental study
AcronymDeep Sea Geochem CaCO3
URLhttps://www.bco-dmo.org/project/743426
CreatedAugust 9, 2018
ModifiedSeptember 14, 2018
Project Description

Biologically-mediated CaCO3 precipitation widely occurs in aquatic systems and is often directly linked to the metabolic activity of microorganisms, which could significantly affect the local environment. An example is oxidation of methane and reduction of sulfate mediated by a consortium of Bacteria and Archaea. In order to investigate geochemistry of CaCO3precipitated abiotically and under microbial activity experimental work was initiated.  The abiotic experiments were performed at different temperatures and pressures (nitrogen and nitrogen-methane mixture).  Further geochemical analyses will allow evaluating of the effect of total pressure and methane partial pressure on the geochemistry of CaCO3. Sulfate reducing bacterial (Desulfovibrio salexigens) was successfully cultured and precipitation experiments on microbially mediated CaCO3 are in progress. This work is relevant to C-DEBI Research Theme I (Activity in the Deep Subseafloor Biosphere: function & rates of global biogeochemical processes) because carbonate growth rate is linked to microbial activity and the rate of methane oxidation.

Project Maintainers
NameAffiliationRoleContact
Rinat GabitovMississippi State University (MSU)Principal Investigator
Karyn L. RogersRensselaer Polytechnic Institute (RPI)Co-Principal Investigator
Chiara BorrelliUniversity of RochesterContact
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