Dataset: Methane sulfate profiles
Deployment: White_Oak_River

Methane and sulfate concentration profiles - sediment cores from White Oak River estuary Station H, October 2012

Principal Investigator:

Karen G. Lloyd (University of Tennessee)

Student:

Jordan Bird (University of Tennessee Knoxville, UTK)

BCO-DMO Data Manager:

Nancy Copley (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

Quantifying the contribution of the deep biosphere in the marine sediment carbon cycle using deep-sea sediment cores from the Baltic Sea (IODP-347 Microbial Quantification)

Current State:

Final no updates expected

Version Date:

2016-06-22

Data URL:

https://www.bco-dmo.org/dataset-deployment/649765/data

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Description

This dataset resulted from a graduate student project called "Culture independent genomic comparisons reveal environmental adaptations for Altiarchaeales". The data is associated with a manuscript submitted to Frontier in Microbiology. The samples are from the White Oak River estuary, North Carolina, Station H to a sediment depth of 75 cm. The project was partially funded by OCE grants.

Related reference: Environmental evidence for net methane production and oxidation in putative ANaerobic MEthanotrophic (ANME) archaea (2011) by Karen G. Lloyd, Marc J. Alperin, Andreas Teske. Contains detailed methods that were nearly identical to the methods used here and similar data from the same location.

Methods & Sampling

Dataset acquisition description

The cores were sequentially cut into 3 cm section from the topmost to bottommost depth. For methane measurements, 3 ml of sediments were taken via cut-off syringe immediately after each section was sliced and quickly added to 60 ml serum vials containing 1 ml of 0.1 M KOH, which were stoppered and crimp-sealed with butyl rubber stoppers to minimize gas loss. After being shaken for 1 min to release methane from sediments (> 99.5% of the methane equilibrated in the headspace), a 5 ml headspace aliquot was displaced with an equal volume of anaerobic distilled water, injected into a 1 ml sample loop, and then analyzed on an Agilent 7890a gas chromatograph equipped with flame ionization detector. For sulfate measurements, plastic 15 ml tubes filled completely with sediment were centrifuged and the resulting porewater was filtered at 0.2 µm, acidified with 10% HCl and measured using a 2010i Dionex ion chromatograph.

Data Processing Description

Dataset Processing Description

Methane concentrations (mmol per litre of porewater) were calculated using the following equation:
[CH₄] = (ρ(CH₄)V_headspace)/(RTφV_sed1000)
where p(CH4) is the partial pressure of methane (in ppmv), Vheadspace is the volume of the serum vial headspace (ml) after the sediment and KOH are added, R is the universal gas constant, T is the temperature at time of measurement in Kelvin and Vsed is the volume (ml) of whole sediment added to the serum vial.

Porosity, φ, was calculated using the formula:
φ = (m_w/ ρ_w)/(m_w/ρ_w+((m_d-S*m_w/1000)/ρ_ds))
where m_w is the mass of the water lost on drying, m_d is the mass of the dried sediment, ρ_w is the density of pure water, ρ_ds is the density of dry sediment (assumed to be 2.5 g cm−3), and S is salinity in grams per kilogram (assumed to be 19 grams per kilogram for all samples).

Standards at sulfate concentrations 0, 0.1, 0.5, 1, 5, 10 mM measure prior to samples from each core and sample peak areas were converted to sulfate concentrations using the standard curves after accounting for the dilution ((peak area * slope + intercept) * 0.7 / 0.6) by the 10% HCl.

No samples have been flagged as below the detection limit.

BCO-DMO Processing:

- added conventional header with dataset name, PI name, version date
- renamed parameters to BCO-DMO and BODC standards
- replaced NaN with nd
- removed CH4_mod data

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-1431598	NSF Division of Ocean Sciences

Instruments

Gas Chromatograph

Supplied Name:

Supplied Description:

Agilent 7890a gas chromatograph equipped with flame ionization detector

Instrument Type

Generic Name: Gas Chromatograph

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB02/

Generic Description:

Instrument separating gases, volatile substances, or substances dissolved in a volatile solvent by transporting an inert gas through a column packed with a sorbent to a detector for assay. (from SeaDataNet, BODC)

Ion Chromatograph

Supplied Name:

Supplied Description:

2010i Dionex ion chromatograph

Instrument Type

Generic Name: Ion Chromatograph

Generic Description:

Ion chromatography is a form of liquid chromatography that measures concentrations of ionic species by separating them based on their interaction with a resin. Ionic species separate differently depending on species type and size. Ion chromatographs are able to measure concentrations of major anions, such as fluoride, chloride, nitrate, nitrite, and sulfate, as well as major cations such as lithium, sodium, ammonium, potassium, calcium, and magnesium in the parts-per-billion (ppb) range. (from http://serc.carleton.edu/microbelife/research_methods/biogeochemical/ic.html)

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
site	site identification	unitless	site
lat	latitude; north is positive	decimal degrees	lat
lon	longitude; east is positive	decimal degrees	lon
depth	depth of core sample	meters	depth
CH4	methane concentration in porewater	mM	no_bcodmo_term
SO4	sulfate concentration in porewater	mM	SO4
core	core identification	unitless	sample
CH4_mod	???methane concentration in porewater - modified in some way???	mM	no_bcodmo_term
porosity	measure of the void (i.e. "empty") spaces in wet sediment volume that evaporated after few weeks at 80ºC (i.e the water) in VV/VT	unitless	porosity

Database

Contribute Data

Dataset: Methane sulfate profiles
Deployment: White_Oak_River

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: Methane sulfate profilesDeployment: White_Oak_River

Dataset acquisition description

Dataset Processing Description

Dataset: Methane sulfate profiles
Deployment: White_Oak_River