Dataset: GP16 Mercury speciation dissolved

Name: Mercury speciation across the US GEOTRACES East Pacific Zonal Transect, from cruise TN303, 2013
Published: 2016-11-18
Keywords: mercury, GEOTRACES, Pacific, oceans

Cite This Dataset

Spatial Extent: N:-10.2294 E:-77.3761 S:-16.0006 W:-152.0385

Temporal Extent: 2013-10-28 - 2013-12-16

Project:

GEOTRACES Pacific Section: Mercury Speciation Along a Zonal Section in the Eastern Tropical South Pacific (EPZT Mercury)

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

Program:

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

Principal Investigator:

Carl Lamborg (University of California-Santa Cruz, UC Santa Cruz)

Co-Principal Investigator:

Chad Hammerschmidt (Wright State University)

Contact:

Katlin Bowman (University of California-Santa Cruz, UC Santa Cruz)

Chad Hammerschmidt (Wright State University)

Carl Lamborg (University of California-Santa Cruz, UC Santa Cruz)

BCO-DMO Data Manager:

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

Version Date:

2016-11-18

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Data URL:

https://www.bco-dmo.org/dataset/643494/data

Mercury speciation across the US GEOTRACES East Pacific Zonal Transect, from cruise TN303, 2013

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Description

This dataset includes concentrations of filtered total mercury, elemental mercury, monomethylmercury and dimethylmercury from 18 full-depth stations (36 depths each), 13 demi stations (12 depths in upper 1000 m), and 4 stations on the South American margin (6–23 depths).

The FISH and BOTTLE data have been split into separate columns as per GEOTRACES Parameter Naming Conventions.The data is the same as version 2016-04-22. The FISH data are to the far right.

* To access the data with the FISH and BOTTLE data merged, see:
http://data.bco-dmo.org/jg/serv/BCO/GEOTRACES/EPZT/Hg_filtered_joined.html0%7Bdir=data.bco-dmo.org/jg/dir/BCO/GEOTRACES/EPZT/,info=data.bco-dmo.org/jg/info/BCO/GEOTRACES/EPZT/Hg_filtered%7D

# version: 2017-07-05 (sample #3095 duplicate records combined)
# replaces version: 2016-06-13 (bottle and fish samples separated; parameter names revised)
# replaces original version: 2016-04-22

Acquisition Description

The dissolved Hg analyses were performed at sea, by both WHOI and Wright State personnel.

See Hg Cook Book for full methodology (PDF)
Detailed method descriptions can be found in Lamborg et al., 2012, Hammerschmidt & Bowman, 2012, Bowman et al., 2015
Sample collection: Cutter & Bruland, 2012
- TMR - trace metal rosette
- FISH – trace-metal clean, surface towed pump system
Sample bottles/cleaning: Hammerschmidt et al., 2012
All analyses were performed at sea aboard the ship.
HgT analysis were all performed by analysts from WHOI:
- Fitzgerald & Gill, 1979, Bloom & Fitzgerald, 1988, Bloom, 1989
- Tekran Model 2500 CVAFS Mercury Detector
- Detection limit: 0.03 pM
- Procedural duplicates: 7 ± 9% (n = 29)
- Recovery of known additions: 97 ± 2% (n = 5)
Hg0 analysis were all performed by analysts from WHOI:
- Fitzgerald & Gill, 1979, Bloom & Fitzgerald, 1988, Bloom, 1989
- Tekran Model 2500 CVAFS Detector
- Detection limit: 0.01 pM
- Procedural duplicates: 20 ± 15%, n = 27
- Recovery of known additions: N/A
MMHg analysis were all performed by analysts from Wright State:
- Bowman & Hammerschmidt, 2011, Tseng et al., 2004, Munson et al., 2014
- Tekran Model 2500 CVAFS Mercury Detector
- Detection limit: 0.02 pM
- Procedural duplicates: 35 ± 22% (n = 6)
- Recovery of known additions: 84 ± 12% (n =3)
DMHg analysis were all performed by analysts from Wright State:
- Bowman & Hammerschmidt, 2011, Tseng et al., 2004, Baya et al., 2013
- Tekran Model 2500 CVAFS Mercury Detector
- Detection limit: 0.002 pM
- Procedural duplicates: 27 ± 20% (n = 17)
- Recovery of known additions: N/A

“lt_DL” indicates that a sample was below the method detection limit.

Sample volumes were used to calculate picomolar concentrations of different mercury species.

Related References:

Baya, P.A., Hollinsworth, J.L. and Hintelmann, H., 2013. Evaluation and optimization of solid adsorbents for the sampling of gaseous methylated mercury species. Anal. Chim. Acta, 786, 61–69.

Bloom, N. 1989. Determination of picogram levels of methylmercury by aqueous phase ethylation, followed by cryogenic gas-chromatography with cold vapor atomic fluorescence detection. Can. J. Fish. Aquat. Sci. 46, 1131–1140.

Bloom, N.S., Fitzgerald, W.F. 1988. Determination of volatile mercury species at the picogram level by low-temperature gas chromatography with cold-vapor atomic fluorescence detection. Anal. Chim Acta 208, 151–161.

Bowman, K.L., Hammerschmidt, C.R. 2011. Extraction of monomethylmercury from seawater for low-femtomolar determination. Limnol. Oceanogr.: Methods 9, 121–128.

Bowman, K.L., Hammerschmidt, C.R., Lamborg, C.H. and Swarr, G., 2015. Mercury in the North Atlantic Ocean: The U.S. GEOTRACES zonal and meridional sections. Deep-Sea Res. Pt. II. 116, 251–261.

Cutter, G.A., Bruland, K.W. 2012. Rapid and noncontaminating sampling system for trace elements in global ocean surveys. Limnol. Oceanogr.: Methods 10, 425–436.

Fitzgerald, W.F., Gill, G.A. 1979. Subnanogram determination of mercury by two-stage gold amalgamation applied to atmospheric analysis. Anal. Chem. 51, 1714–1720.

Hammerschmidt, C.R., Bowman, K.L. 2012. Vertical methylmercury distribution in the subtropical North Pacific Ocean. Mar. Chem. 132, 77–82.

Hammerschmidt, C.R., Bowman, K.L., Tabatchnick, M.D., Lamborg, C.H. 2011. Storage bottle material and cleaning for determination of total mercury in seawater. Limnol. Oceanogr.: Methods 9, 426–431.

Lamborg, C.H., Hammerschmidt, C.R., Gill, G.A., Mason, R.P., Gichuki, S. 2012. An intercomparison of procedures for the determination of total mercury in seawater and recommendations regarding mercury speciation during GEOTRACES cruises. Limnol. Oceanogr.: Methods, 10, 90-100.

Munson, K.M., Babi, D. and Lamborg, C.H., 2014. Determination of monomethylmercury from seawater with ascorbic acid-assisted direct ethylation. Limnol. Oceanogr.-Meth. 12, 1–9.

Tseng, C.-M., Hammerschmidt, C.R., Fitzgerald, W.F. 2004. Determination of methylmercury in environmental matrixes by on-line flow injection and atomic fluorescence spectrometry. Anal. Chem. 76, 7131–7136.

Processing Description

BCO-DMO Processing:

- added conventional header with dataset name, PI name, version date
- renamed parameters to BCO-DMO standard
- added cruise_id
- replaced blank cells with nd (no data)
- replaced '<' with 'lt_' ('less than')
- bottle and fish samples separated; parameter names revised

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.

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1232979
NSF Division of Ocean Sciences	OCE-1232760

Deployments

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

Instruments

Cold Vapor Atomic Fluorescence Spectrophotometer

(more info)

Short Name: CVAFS

Generic Description

A Cold Vapor Atomic Fluorescent Spectrophotometer (CVAFS) is an instrument used for quantitative determination of volatile heavy metals, such as mercury. CVAFS make use of the characteristic of mercury that allows vapor measurement at room temperature. Mercury atoms in an inert carrier gas are excited by a collimated UV light source at a particular wavelength. As the atoms return to their non-excited state they re-radiate their absorbed energy at the same wavelength. The fluorescence may be detected using a photomultiplier tube or UV photodiode.

PI supplied instrument name:

Dataset-specific description

Pump surface

(more info)

Short Name: Pump surface

Community Standard Description

Generic Description

A source of uncontaminated near-surface seawater pumped onto the deck of the research vessel that can be sampled and analyzed. This pumped seawater supply is from an over-the-side pumping system, and is therefore different from the vessel underway seawater system.

PI supplied instrument name:

Dataset-specific description

trace-metal clean, surface towed pump system

Trace Metal Bottle

(more info)

Short Name: TM Bottle

Community Standard Description

Generic Description

Trace metal (TM) clean rosette bottle used for collecting trace metal clean seawater samples.

PI supplied instrument name:

Dataset-specific description

Trace metal rosette

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise_id	Official cruise identifier	unitless	cruise_id
cruise_name	cruise name used by PI	unitless	cruise_name
STNNBR	station number; provided in original data submission.	integer	sta
date	date; provided in original data submission.	yyyymmdd	date
time	UTC time; provided in original data submission.	HHMM	time
lat	latitude; north is positive; provided in original data submission.	decimal degrees	lat
lon	longitude; east is positive; provided in original data submission.	decimal degrees	lon
GEOTRC_SAMPNO	Unique identifying number for US GEOTRACES sample. PI-supplied values were identical to those in the intermediate US GEOTRACES master file. Originally submitted as 'sample'; this parameter name has been changed to conform to BCO-DMO's GEOTRACES naming conventions.	integer	sample
GEOTRC_EVENTNO	Unique identifying number for US GEOTRACES sampling events. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	unitless	event
inst	instrument; provided in original data submission.	unitless	instrument
CASTNO	Cast identifier numbered consecutively within a station. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	unitless	cast
BTL_LAT	Latitude of bottle firing; north is positive. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	decimal degrees	lat
BTL_LON	Lonitude of bottle firing; east is positive. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	decimal degrees	lon
ISO_DATETIME_UTC_START_EVENT	Event start date/time (UTC) formatted to ISO8601 standard. T indicates start of time string; Z indicates UTC. Calculated from original date and time fields.	YYYY-mm-ddTHH:MM:SS.ssZ	ISO_DateTime_UTC
BTL_ISO_DATETIME_UTC	Bottle date/time (UTC) formatted to ISO8601 standard. T indicates start of time string; Z indicates UTC. Calculated from original date and time fields.	YYYY-mm-ddTHH:MM:SS.ssZ	ISO_DateTime_UTC
SAMPNO	Sample number; Values were added from the intermediate US GEOTRACES master file (see Processing Description).	unitless	sample
BTLNBR	Alphanumeric characters identifying bottle type (e.g. NIS representing Niskin and GF representing GOFLO) and position on a CTD rosette. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	unitless	bottle
BTLNBR_FLAG_W	Quality flag: 2) ok; 3) questionable; 4) bad analysis; 5) sample lost; 6) mean of replicates	unitless	q_flag
depth	Depth as reported by PI (CTD coordinates as included in the Pacific cruise Report.)	meters	depth
Hg_TD_CONC_BOTTLE	Total dissolved concentration of mercury from CTD bottle samples (includes gaseous Hg)	picomolar (pM)	trace_metal_conc
Hg_TD_CONC_BOTTLE_FLAG_W	Quality flag: 2) ok; 3) questionable; 4) bad analysis; 5) sample lost; 6) mean of replicates; 9) sample was not collected for Hg analysis	unitless	q_flag
Hg0_D_CONC_BOTTLE	Concentration of gaseous elemental mercury from CTD bottle samples	picomolar (pM)	trace_metal_conc
Hg0_D_CONC_BOTTLE_FLAG_W	Quality flag: 2) ok; 3) questionable; 4) bad analysis; 5) sample lost; 6) mean of replicates; 9) sample was not collected for Hg analysis	unitless	q_flag
MMHg_D_CONC_BOTTLE	monomethylmercury concentration from CTD bottle samples	picomolar (pM)	trace_metal_conc
MMHg_D_CONC_BOTTLE_FLAG_W	Quality flag: 2) ok; 3) questionable; 4) bad analysis; 5) sample lost; 6) mean of replicates; 9) sample was not collected for Hg analysis	unitless	q_flag
DMHg_D_CONC_BOTTLE	dimethylmercury concentration from CTD bottle samples	picomolar (pM)	trace_metal_conc
DMHg_D_CONC_BOTTLE_FLAG_W	Quality flag: 2) ok; 3) questionable; 4) bad analysis; 5) sample lost; 6) mean of replicates; 9) sample was not collected for Hg analysis	unitless	q_flag
Hg_TD_CONC_FISH	Total dissolved concentration of mercury from GEO-Fish samples (includes gaseous Hg)	picomolar (pM)	trace_metal_conc
Hg_TD_CONC_FISH_FLAG_W	Quality flag: 2) ok; 3) questionable; 4) bad analysis; 5) sample lost; 6) mean of replicates; 9) sample was not collected for Hg analysis	unitless	q_flag

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Dataset: GP16 Mercury speciation dissolved