Dataset: Sediment pushcore porewater geochemistry from southern California seeps May 2021

Name: Porewater geochemistry from sediment pushcores collected by ROV Doc Ricketts from Southern California Seeps in May 2021
Published: 2023-09-13
Keywords: oceans

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Spatial Extent: N:36.7767 E:-117.782 S:32.9042 W:-122.085

Temporal Extent: 2021-05-19 - 2021-05-24

Project:

Collaborative Research: Redefining the footprint of deep ocean methane seepage for benthic ecosystems (Methanosphere)

Co-Principal Investigator:

Shana Goffredi (Occidental College)

Victoria J. Orphan (California Institute of Technology, Caltech)

Scientist:

John Stedman Magyar (California Institute of Technology, Caltech)

BCO-DMO Data Manager:

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2023-09-13

Restricted:

Validated:

Current State:

Data not available

Porewater geochemistry from sediment pushcores collected by ROV Doc Ricketts from Southern California Seeps in May 2021

Abstract:

This dataset provides geochemical data (major ions) for porewaters from sediment pushcores collected by a remotely-operated vehicle (ROV) deployed from the R/V Western Flyer in May 2021 (WF05-21) at the Del Mar and Santa Monica Seeps and in Newport Canyon, California, USA. Cores were sectioned into 1-3 centimeter (cm) horizons, and porewater was extracted shipboard using an argon-pressurized squeezer. Porewater samples were frozen at sea and thawed just before analysis. This dataset reports concentrations of fluoride, acetate, formate, chloride, bromide, nitrate, sulfate, thiosulfate, and phosphate anions and lithium, sodium, potassium, magnesium, and calcium cations. Measurements were made using the Thermo Dual Dionex Integrion HPIC ion chromatography system with either a 250-millimeter (mm) Dionex IonPac AS19-4um column (anions) or a 250 mm Dionex IonPac CS16-4um column (cations), in the Resnick Water and Environment Laboratory at the California Institute of Technology (Caltech).

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Methods & Sampling

Sediment pushcores were collected by a remotely-operated vehicle (ROV Doc Ricketts) from the R/V Western Flyer in May 2021 (cruise ID WF05-21) at the Del Mar Seep (32.9043, -117.7824), Santa Monica Seep Mound 800 (33.7993, -118.6465), Santa Monica Seep Mound 863 (33.7891, -118.6683), and Newport Canyon (33.5450, -117.9251). Pushcores were manually sectioned into 1- or 3-centimeter (cm) horizons using plastic rings, and porewaters were extracted using a KC Denmark squeezer. Samples for ion chromatography were frozen shipboard and thawed immediately prior to analysis. Measurements were made using a Thermo Dual Dionex Integrion HPIC ion chromatography system with either a 250-millimeter (mm) Dionex IonPac AS19-4um column (anions) with 50 mm guard column or a 250 mm Dionex IonPac CS16-4um column (cations) with a 50 mm guard column, in the Resnick Water and Environment Laboratory at the California Institute of Technology (Caltech).

Data Processing Description

100 microliter (uL) samples were diluted 50x in milliQ nanopure water before running. Standard curves were generated using calibration standards diluted similarly to samples, with 100 uL of 500 millimolar (mM) NaCl added to mimic typical seawater sample peak behavior. Analyte peaks were integrated and values were calculated using the standards automatically in the Chromeleon software, with manual QC to ensure regular peak shapes.

Known issues or problems:
Na and Cl are not quantitative, as the standards have an excess of each spiked in, above the upper limit of quantification. Formate values reported as 'ND' indicate they are below the LoQ but not LoD. Ca elutes near the end of the run, and occasionally is not captured in its entirety.

BCO-DMO Processing

- Imported original file "20230630_WF05-21_Ions_for_NSF.xlsx" into the BCO-DMO system.
- Flagged 'ND' and 'NOT_MEASURED' as missing data identifiers but retained this notation in the dataset.
- Converted the date column YYYY-MM-DD format.
- Created the ISO 8601 date/time field (UTC) using the Date_UTC and Time_UTC columns as input.
- Saved the final file as "908217_v1_porewater_biogeochem.csv".

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-2048666

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
WF05-21	WF0521	2021-05-19	R/V Western Flyer	Shana Goffredi (Co-Chief Scientist) Victoria J. Orphan (Co-Chief Scientist)	data info

Instruments

Ion Chromatograph

Supplied Name: Thermo Dual Dionex Integrion HPIC ion chromatography system

Supplied Description:

Thermo Dual Dionex Integrion HPIC ion chromatography system with either a 250 mm Dionex IonPac AS19-4um column (anions) with 50 mm guard column or a 250 mm Dionex IonPac CS16-4um column (cations) with a 50 mm guard column, in the Resnick Water and Environment Laboratory at the California Institute of Technology (Caltech).

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)

Push Corer

Supplied Name: pushcores

Supplied Description:

Sediment pushcores were collected by ROV.

Instrument Type

Generic Name: Push Corer

Generic Description:

Capable of being performed in numerous environments, push coring is just as it sounds. Push coring is simply pushing the core barrel (often an aluminum or polycarbonate tube) into the sediment by hand. A push core is useful in that it causes very little disturbance to the more delicate upper layers of a sub-aqueous sediment.

Description obtained from: http://web.whoi.edu/coastal-group/about/how-we-work/field-methods/coring/

ROV Doc Ricketts

Supplied Name:

Supplied Description:

ROV Doc Ricketts is operated by the Monterey Bay Aquarium Research Institute (MBARI). ROV Doc Ricketts is capable of diving to 4000 meters (about 2.5 miles). The R/V Western Flyer was the support vessel for Doc Ricketts and was designed with a center well whose floor can be opened to allow Doc Ricketts to be launched from within the ship into the water below. For a complete description see: https://www.mbari.org/technology/rov-doc-ricketts/

Instrument Type

Generic Name: ROV Doc Ricketts

Acronym: Doc Ricketts

Generic Description:

The remotely operated vehicle (ROV) Doc Ricketts is operated by the Monterey Bay Aquarium Research Institute (MBARI). ROV Doc Ricketts is capable of diving to 4000 meters (about 2.5 miles). The R/V Western Flyer is the support vessel for Doc Ricketts and was designed with a center well whose floor can be opened to allow Doc Ricketts to be launched from within the ship into the water below. For a complete description, see: https://www.mbari.org/at-sea/vehicles/remotely-operated-vehicles/rov-doc-ricketts/

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
serial	Internal Orphan Lab identifier (sample serial number)	unitless	sample
Fluoride	concentration of fluoride ion	millimolar (mM)	fluoride_ion
Acetate	concentration of acetate ion. ND = below level of quantification; NOT_MEASURED = this ion was not measured for this sample.	millimolar (mM)	C2H3O2
Formate	concentration of formate ion. ND = below level of quantification; NOT_MEASURED = this ion was not measured for this sample.	millimolar (mM)	CHO2
Chloride	concentration of chloride ion. ND = below level of quantification; NOT_MEASURED = this ion was not measured for this sample.	millimolar (mM)	chloride
Bromide	concentration of bromide ion	millimolar (mM)	bromides
Nitrate	concentration of nitrate ion. ND = below level of quantification; NOT_MEASURED = this ion was not measured for this sample.	millimolar (mM)	NO3
Sulfate	concentration of sulfate ion. ND = below level of quantification; NOT_MEASURED = this ion was not measured for this sample.	millimolar (mM)	SO4
Thiosulfate	concentration of thiosulfate ion. ND = below level of quantification; NOT_MEASURED = this ion was not measured for this sample.	millimolar (mM)	S2O3
Phosphate	concentration of phosphate ion. ND = below level of quantification; NOT_MEASURED = this ion was not measured for this sample.	millimolar (mM)	PO43-
Lithium	concentration of lithium ion (Li+). ND = below level of quantification; NOT_MEASURED = this ion was not measured for this sample.	millimolar (mM)	Li
Sodium	concentration of sodium ion (Na+)	millimolar (mM)	Sodium_cation
Ammonium	concentration of ammonium ion (NH4+). ND = below level of quantification; NOT_MEASURED = this ion was not measured for this sample.	millimolar (mM)	NH4
Potassium	concentration of potassium ion (K+)	millimolar (mM)	K
Magnesium	concentration of magnesium ion (Mg2+)	millimolar (mM)	Mg
Calcium	concentration of calcium ion (Ca2+). ND = below level of quantification; NOT_MEASURED = this ion was not measured for this sample.	millimolar (mM)	Calcium_2_cation
pH	pH value, measured shipboard. ND = below level of quantification; NOT_MEASURED = was not measured for this sample.	unitless	pH
Dive	Dive number of the ROV Doc Ricketts	unitless	dive_id
Lat	Latitude	decimal degrees	lat
Long	Longitude, with west longitude negative	decimal degrees	lon
Horizon	depth (cm) in sediment, measured from top of core	cenimeters (cm)	depth_core
Date_UTC	core collection date (UTC) Format: %Y-%m-%d	unitless	date
Time_UTC	core collection time (UTC) Format: %H:%M:%S	unitless	time
Depth_m	ocean depth in meters at the sampling location	meters (m)	depth
Station	name of the sampling site	unitless	station
Sample_Name	the sample name, which is composed of the dive number and the ROV pushcore number	unitless	sample
ISO_DateTime_UTC	core collection date and time (UTC) in ISO 8601 format Format: %Y-%m-%dT%H:%M:%SZ	unitless	ISO_DateTime_UTC

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Dataset: Sediment pushcore porewater geochemistry from southern California seeps May 2021