Dataset: GP16 Dissolved Inorganic Carbon

Name: Seawater Inorganic Carbon Data (DIC) from the R/V Thomas G. Thompson TN303 cruise in the Eastern Tropical Pacific from October to December 2013 (U.S. GETORACES EPZT project)
Published: 2017-05-03
Keywords: oceans

Cite This Dataset

Spatial Extent: N:-10.224 E:-77.3761 S:-16.0006 W:-152.0006

Temporal Extent: 2013-10-29 - 2013-12-18

Project:

Collaborative Research: Seawater Inorganic and Organic Carbon Measurements for the US GEOTRACES Eastern Pacific Zonal Transect (EPZT Carbon)

U.S. GEOTRACES East Pacific Zonal Transect (GP16) (U.S. GEOTRACES EPZT)

Program:

U.S. GEOTRACES (U.S. GEOTRACES)

Principal Investigator:

Nicholas Bates (Bermuda Institute of Ocean Sciences, BIOS)

BCO-DMO Data Manager:

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

Version:

03 May 2017

Version Date:

2017-05-03

Restricted:

Validated:

Current State:

Final no updates expected

Seawater Inorganic Carbon Data (DIC) from the R/V Thomas G. Thompson TN303 cruise in the Eastern Tropical Pacific from October to December 2013 (U.S. GETORACES EPZT project)

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Description

Dissolved inorganic carbon (DIC) from samples collected on the 2013 US GEOTRACES EPZT cruise, TN303.

Methods & Sampling

Sampling:
Seawater samples for carbonate chemistry were collected for the entire water column at all of the GEOTRACES CTD-hydrocast stations. Samples for DIC awere drawn from the Niskin samplers into the clean 500 ml size Pyrex glass reagent bottles, using established gas sampling protocols (Bates et al, 1996; Dickson et al., 2007). A headspace of <1% of the bottle volume was left to allow for water expansion and all samples were poisoned with 100 ul of saturated HgCl solution to prevent biological alteration. Bottles were sealed with ground-glass stoppers and Apiezon vacuum grease. Rubber bands were placed around the lip of the bottle and stopper to provide positive closure. Samples were returned to the Bermuda Institute of Ocean Sciences (BIOS) for analysis. Similar sampling protocols were established at BIOS for sampling at the BATS (Bates et al., 1996a,b; Bates, 2001). Samples were typically analyzed within three months of collection.

Analytical Procedures:
DIC was measured by a gas extraction/coulometric technique (see Bates et al., 1996a,b for details), using a SOMMA (Single-Operator Multi-Metabolic Analyzer) to control the pipetting and extraction of seawater samples and a UIC CO2 coulometer detector. DIC samples were analyzed using a VINDTA 3C (Marianda Com). Both analytical systems use identical chemical approaches for the measurement of DIC in seawater, with the VINDTA 3C providing an updated instrument for use over the last decade (Bates et al., 2012). The precision of DIC analyses of this system is typically better than 0.025% (~0.4 umoles/kg) based on duplicate and triplicate analyses of >4000 seawater samples analyzed at BIOS from 1992 to present. Seawater certified reference materials (CRM's; prepared by A.G. Dickson, Scripps Institution of Oceanography) were analyzed to ensure that the accuracy of DIC was within 0.03% (~0.5 umoles/kg).

Data Processing Description

BCO-DMO Processing:
- changed "DIC #" to "DIC_NUM", otherwise retained submitted parameter names (submitted names were already formatted in accordance with GEOTRACES conventions);
- formatted time to HHMM;
- removed leading spaces from EXPOCODE and BTLNBR columns;
- corrected EXPOCODE (was incorrect due to original file containing scientific notation);
- joined to BCO-DMO EPZT master file; added GEOTRC_INSTR, ISO_DATETIME_UTC_START_EVENT, and BTL_ISO_DATETIME_UTC columns;
- removed PI-provided date and time for consistency with other GEOTRACES datasets;
- added cruise_id column.

Additional GEOTRACES Processing:
As was done for the GEOTRACES-NAT data, BCO-DMO added standard US GEOTRACES information, such as the US GEOTRACES event number, to each submitted dataset lacking this information. To accomplish this, BCO-DMO compiled a 'master' dataset composed of the following parameters:

cruise_id, EXPOCODE,SECT_ID, STNNBR, CASTNO, GEOTRC_EVENTNO, GEOTRC_SAMPNO, GEOTRC_INSTR, SAMPNO, GF_NO, BTLNBR, BTLNBR_FLAG_W, DATE_START_EVENT, TIME_START_EVENT, ISO_DATETIME_UTC_START_EVENT, EVENT_LAT, EVENT_LON, DEPTH_MIN, DEPTH_MAX, BTL_DATE, BTL_TIME, BTL_ISO_DATETIME_UTC, BTL_LAT, BTL_LON, ODF_CTDPRS, SMDEPTH, FMDEPTH, BTMDEPTH, CTDPRS, CTDDEPTH.

This added information will facilitate subsequent analysis and inter comparison of the datasets.

Bottle parameters in the master file were taken from the GT-C_Bottle and ODF_Bottle datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the TN303 Event Log (version 30 Oct 2014). Where applicable, pump information was taken from the PUMP_Nuts_Sals dataset.

A standardized BCO-DMO method (called "join") was then used to merge the missing parameters to each US GEOTRACES dataset, most often by matching on sample_GEOTRC or on some unique combination of other parameters.

If the master parameters were included in the original data file and the values did not differ from the master file, the original data columns were retained and the names of the parameters were changed from the PI-submitted names to the standardized master names. If there were differences between the PI-supplied parameter values and those in the master file, both columns were retained. If the original data submission included all of the master parameters, no additional columns were added, but parameter names were modified to match the naming conventions of the master file.

See the dataset parameters documentation for a description of which parameters were supplied by the PI and which were added via the join method.

Data Files

File
DIC_joined.csv (Comma Separated Values (.csv), 125.90 KB) MD5:752f41fb75602adc53e06e49907cdea5 Primary data file for dataset ID 699295

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1233706

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
TN303	GP16 GEOTRACES EPZT GEOTRACES East Pacific Zonal Transect (EPZT) GT13 325020131025	2013-10-25	R/V Thomas G. Thompson	James W. Moffett (Chief Scientist) Gregory A. Cutter (Co-Chief Scientist) Christopher R. German (Co-Chief Scientist)	data info

Instruments

CO2 Analyzer

Supplied Name: SOMMA (Single-Operator Multi-Metabolic Analyzer)

Supplied Description:

DIC was measured by a gas extraction/coulometric technique (see Bates et al., 1996a,b for details), using a SOMMA (Single-Operator Multi-Metabolic Analyzer) to control the pipetting and extraction of seawater samples and a UIC CO2 coulometer detector.

Instrument Type

Generic Name: CO2 Analyzer

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/382/

Generic Description:

Measures atmospheric carbon dioxide (CO2) concentration.

CO2 Coulometer

Supplied Name: UIC CO2 coulometer detector

Supplied Description:

Instrument Type

Generic Name: CO2 Coulometer

Acronym: CO2 coulometer

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB12

Generic Description:

A CO2 coulometer semi-automatically controls the sample handling and extraction of CO2 from seawater samples. Samples are acidified and the CO2 gas is bubbled into a titration cell where CO2 is converted to hydroxyethylcarbonic acid which is then automatically titrated with a coulometrically-generated base to a colorimetric endpoint.

MARIANDA VINDTA 3C total inorganic carbon and titration alkalinity analyser

Supplied Name: VINDTA 3C

Supplied Description:

DIC samples were analyzed using a VINDTA 3C (Marianda Com).

Instrument Type

Generic Name: MARIANDA VINDTA 3C total inorganic carbon and titration alkalinity analyser

Acronym: inorganic carbon and alkalinity analyser

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0481/

Generic Description:

The Versatile INstrument for the Determination of Total inorganic carbon and titration Alkalinity (VINDTA) 3C is a laboratory alkalinity titration system combined with an extraction unit for coulometric titration, which simultaneously determines the alkalinity and dissolved inorganic carbon content of a sample. The sample transport is performed with peristaltic pumps and acid is added to the sample using a membrane pump. No pressurizing system is required and only one gas supply (nitrogen or dry and CO2-free air) is necessary. The system uses a Metrohm Titrino 719S, an ORION-Ross pH electrode and a Metrohm reference electrode. The burette, the pipette and the analysis cell have a water jacket around them. Precision is typically +/- 1 umol/kg for TA and/or DIC in open ocean water.

Niskin bottle

Supplied Name: Niskin samplers

Supplied Description:

Seawater samples for carbonate chemistry were collected for the entire water column at all of the GEOTRACES CTD-hydrocast stations. Samples for DIC awere drawn from the Niskin samplers into the clean 500 ml size Pyrex glass reagent bottles.

Instrument Type

Generic Name: Niskin bottle

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0412/

Generic Description:

A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24, or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc.

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise_id	Cruise identification	unitless	cruise_id
SECT_ID	Cruise section identifier; EPZT = GEOTRACES East Pacific Zonal Transect	unitless	cruise_part
EXPOCODE	Cruise EXPO code.	unitless	EXPOCODE
STNNBR	Station number	unitless	station
GEOTRC_EVENTNO	GEOTRACES event number	unitless	event
CASTNO	Cast number	unitless	cast
LATITUDE	Latitude; positive = North	decimal degrees	lat
LONGITUDE	Longitude; negative = West	decimal degrees	lon
ISO_DATETIME_UTC_START_EVENT	Date and time, formatted to the ISO 8601 standard, at the start of the sampling event, according to the event log. Format: YYYY-MM-DDTHH:MM:SS[.xx]Z. Added from BCO-DMO EPZT master data file.	unitless	ISO_DateTime_UTC
BTMDEPTH	Bottom depth	meters	depth_bottom
GEOTRC_INSTR	Sampling instrument; added from BCO-DMO EPZT master data file	unitless	instrument
GEOTRC_SAMPNO	Unique GEOTRACES sample number	unitless	sample
DIC_NUM	DIC sample number	unitless	sample
SAMPNO	Sequential sample number within the cast (usually corresponds to bottle number).	unitless	bottle
BTLNBR	Bottle number; typically 1-24.	unitless	bottle
BTLNBR_FLAG_W	Bottle number quality flag; follows WOCE conventions. 2 = no problems noted; 3 = leaking; 4 = did not trip correctly; 9 = samples not drawn from this bottle	unitless	flag
CTDPRS	CTD pressure	decibars	press
CTDDEPTH	CTD bottle firing depth	meters	depth
CTDTMP	CTD temperature	degrees Celsius	temp
CTDSAL	CTD salinity (PSS-78). CTDSAL is the calculated corrected value of salinity derived from the conductivity sensors on the CTD unit at the time of the bottle trip. CTDSAL is compared with SALNTY which is the PSS-78 value measured from the actual samples drawn from the niskin bottles themselves. Reporting both is meant, among other things, as a of show the goodness of fit, source of quality coding and offer alternative for measurements/calculations if one of those values is missing or lacking a good quality code.	unitless	sal
CTDSAL_FLAG_W	CTDSAL quality flag; follows WOCE conventions. 2 = good; 3 = questionable; 4 = bad; 9 = missing data.	unitless	flag
SALNTY	Salinity; the PSS-78 value measured from the actual samples drawn from the niskin bottles themselves	unitless	sal
SALNTY_FLAG_W	SALNTY quality flag; follows WOCE conventions. 2 = good; 3 = questionable; 4 = bad; 9 = missing data.	unitless	flag
SALTREF	SELFTREF is salinity reference in TEOS-10 (http://www.teos-10.org/) and defined as absolute salinity units (G/KG) published in 2010. That compared with the classic salinity measurement in practical salinity units (PSS-78).	grams per kilogram (g/kg)	sal
SALTREF_FLAG_W	SALTREF quality flag; follows WOCE conventions. 2 = good; 3 = questionable; 4 = bad; 9 = missing data.	unitless	flag
DIC	Dissolved inorganic carbon	micromoles per kilogram (umoles/kg)	DIC
DIC_flag	DIC quality flag; follows WOCE conventions. 2 = good; 3 = questionable; 4 = bad; 9 = missing data.	unitless	flag
BTL_ISO_DATETIME_UTC	Date and time, formatted to the ISO 8601 standard, at the time of bottle firing. Format: YYYY-MM-DDTHH:MM:SS[.xx]Z. Added from BCO-DMO EPZT master data file.	unitless	ISO_DateTime_UTC

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Dataset: GP16 Dissolved Inorganic Carbon