Dataset: por_nut_chem_PF2
Deployment: PacFlux_II_cruise_2

Porosity and pore water nutrient chemistries, sediment cores

Principal Investigator:

William M. Berelson (University of Southern California, USC-HIMS)

Co-Principal Investigator:

Douglas E. Hammond (University of Southern California, USC-HIMS)

BCO-DMO Data Manager:

Cynthia L. Chandler (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

U.S. JGOFS Equatorial Pacific (EqPac)

Version:

January 2, 2002

Version Date:

2002-01-02

Data URL:

https://www.bco-dmo.org/dataset-deployment/452128/data

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Description

Porosity and pore water nutrient chemistries, sediment cores

Methods & Sampling

Dataset acquisition description

PI: Will Berelson and Doug Hammond
of:, University of Southern California
dataset: Porosity and pore water nutrient
chemistries from sediment cores
dates: December 11, 1991 to January 31, 1992
location: N: 0.000 S: 0.000 W: -139.93 E: -102.91
project/cruise: EqPac/PacFluxII
ship: Vickers

Methodology:

McManus, J., D.E. Hammond, W.M. Berelson, T.E. Kilgore. D.J. DeMaster, O.
G. Ragueneau, and R.W. Collier. 1995. Early diagenesis of biogenic opal:
Dissolution rates, kinetics, and paleoceanographic implications. Deep Sea
Research. 42, 871-903.

Hammond, D.E., J. McManus, W.M. Berelson, T.E. Kilgore, and R. Pope, 1996,
Early diagenesis of organic material in Equatorial Pacific Sediments:
Stoichiometry and Kinetics. Deep Sea Research II, 43, 1365-1412.

PI Notes:
1..Ammonia and Nitrate+Nitrite appear to be significantly influenced by artifacts
related to core retrieval and centrifugation.
2..Measured silicic acid has been temperature corrected for warming during
centrifugation.
3..Bottom water (BW) values are from (whole-core squeezing (WCS) cores, hydro data
or landers).
4..Porosity is defined as the fraction of sediment volume occupied by pore
water, so it is dimensionless. The prodecure used to measure it was to
weigh sediment wet, dry the sediment at 60ï¿½ C until it reached a constant
weight, and re-weigh. A density of solid phases D=2.6 g/cc, and a salinity
S=35 psu were assumed. The porosity was calculated from the expression
below, where Ww is wet weight and Wd is dry weight (both corrected for the
tare weight of the empty container):

Porosity = Vpw/(Vpw+Vsed)
where Vpw = Ww/(0.99)
and Vsed = (Wd - (Ww-Wd)(S/990))/D
The factor 0.99 is grams H2O per cc sea water, and the factor 990 is grams
H2O per kg sea water.

DMO Note:
1..Additional porosity/pore water data for this area are available from PACFLUX II,
a JGOFS pilot project. See Berelson and Hammond's por_nut_chem_PF2 porosity and pore water
nutrient chemistry data from the PACFLUX II cruise.

Data Processing Description

Dataset Processing Description

More information about this dataset deployment

Instruments

Box Corer

Supplied Description:

Instrument Type

Generic Name: Box Corer

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/51/

Generic Description:

General description of a box corer:

A box corer is a marine geological tool that recovers undisturbed soft surface sediments. It is designed for minimum disturbance of the sediment surface by bow wave effects. Traditionally, it consists of a weighted stem fitted to a square sampling box. The corer is lowered vertically until it impacts with the seabed. At this point the instrument is triggered by a trip as the main coring stem passes through its frame. While pulling the corer out of the sediment a spade swings underneath the sample to prevent loss. When hauled back on board, the spade is under the box. (definition from the SeaVox Device Catalog)

Box corers are one of the simplest and most commonly used types of sediment corers. The stainless steel sampling box can contain a surface sediment block as large as 50cm x 50cm x 75cm with negligible disturbance. Once the sediment is recovered onboard, the sediment box can be detached from the frame and taken to a laboratory for subsampling and further analysis. The core sample size is controlled by the speed at which the corer is lowered into the ocean bottom. When the bottom is firm, a higher speed is required to obtain a complete sample. A depth pinger or other depth indicator is generally used to determine when the box is completely filled with sediment. Once the core box is filled with sediment, the sample is secured by moving the spade-closing lever arm to lower the cutting edge of the spade into the sediment, until the spade completely covers the bottom of the sediment box. (definition from Woods Hole Oceanographic Institution).

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
NH3_pw	ammonia concentration in sediment pore water	micromoles/liter	no_bcodmo_term
depth_begin	depth at which measurement/sample began	centimeters	no_bcodmo_term
depth_end	depth at which measurement/sample ended	centimeters	no_bcodmo_term
depth_core	depth in core, mid-point of interval sampled	centimeters	no_bcodmo_term
lat	latitude; minus = South	decimal degrees	lat
lon	longitude; minus = West	decimal degrees	lon
NO3_NO2_pw	nitrate plus nitrite concentration in sediment pore water	micromoles/liter	no_bcodmo_term
sample	sample identification, BW indicates bottom water		sample
porosity	sediment porosity		no_bcodmo_term
Si_acid_pw_t	silicic acid concentration in sediment pore water; temperature corrected for warming during centrifugation	micromoles/liter	no_bcodmo_term
sta_name	station name		no_bcodmo_term

Database

Contribute Data

Dataset: por_nut_chem_PF2
Deployment: PacFlux_II_cruise_2

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: por_nut_chem_PF2Deployment: PacFlux_II_cruise_2

Dataset acquisition description

Dataset Processing Description

Dataset: por_nut_chem_PF2
Deployment: PacFlux_II_cruise_2