Dataset: GT10-11 - Hg Particulate
Deployment: KN204-01

Particulate total mercury and monomethylmercury - US GEOTRACES NATZ

Principal Investigator:

Carl Lamborg (Woods Hole Oceanographic Institution, WHOI)

Co-Principal Investigator:

Chad Hammerschmidt (Wright State University)

BCO-DMO Data Manager:

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

Project:

U.S. GEOTRACES North Atlantic Transect (GA03) (U.S. GEOTRACES NAT)

Current State:

Final no updates expected

Version:

18 Jan 2013

Deployment Synonyms:

GA03, GT11, KN204-01A, KN204-01B, USGT-NAT-2011, USGNAZT, GNAT, 316N20111106, KN204-1

Version Date:

2013-03-05

Data URL:

https://www.bco-dmo.org/dataset-deployment/455728/data

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Description

Particulate total mercury and monomethylmercury across the US GEOTRACES North Atlantic Zonal Section.

This dataset includes concentrations of particulate total mercury and particulate monomethylmercury from surface water to bottom water at 22 stations across the cruise path. Particle samples were collected with a multiple-unit large-volume in situ filtration system that collected a size fraction between 1 and 51 um.

Methods & Sampling

Dataset acquisition description

- Sample collection: Bishop et al., 2012. Samples were collected from the surface at 30 meters to the ocean floor, as deep as 5800 meters. Approximately 16 depths were sampled at each station. Used the ODF Niskin rosette.

- Particulate samples were frozen and transported to Wright State University (Dayton, OH) where they were analyzed within 3 months of collection. Filter punches were digested in acid-cleaned polypropylene containers with 8 mL of 2N HNO3 (Baker Instra-Analyzed). After analysis of MMHg, an aliquot of digestate was oxidized with BrCl solution for total Hg determination: Hammerschmidt & Fitzgerald, 2006.

- HgT analysis:
    Fitzgerald & Gill, 1979; Bloom & Fitzgerald, 1988; Bloom, 1989
    Tekran Model 2500 CVAFS Mercury Detector
    Detection limit: 0.03 pM
    Procedural duplicates: 3 ± 3 relative percent difference (n=18)
    Recovery of known additions: 106% recovery (n=1)

-MMHg analysis:
    Tseng et al., 2004
    Tekran Model 2500 CVAFS Mercury Detector
    Detection limit: 2 fM
    Filter digestates contained insufficient analyte for analysis of either procedural duplicates or recovery of known additions. Particulate MMHg concentrations were < 4 fM and required the maximum amount of sample volume to obtain a signal.

Data Processing Description

Dataset Processing Description

"lt_DL" indicates that a sample was below the method detection limit.
Sample volumes were used to calculate either picomolar or femtomolar concentrations of different mercury species.

Related files and references:

Bishop, J.K.B., Lam, P.J., Wood, T.J. 2012. Getting good particles: Accurate sampling of particles by large volume in-situ filtration.

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.

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., Fitzgerald, W. F. 2006. Bioaccumulation and trophic transfer of methylmercury in Long Island Sound. Arch. Environ. Contam. Toxicol. 51, 416-424.

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.

Additional GEOTRACES Processing:
After the data were submitted to the International Data Management Office, BODC, the office noticed that important identifying information was missing in many datasets. With the agreement of BODC and the US GEOTRACES lead PIs, 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: station_GEOTRC, cast_GEOTRC (bottle and pump data only), event_GEOTRC, sample_GEOTRC, sample_bottle_GEOTRC (bottle data only), bottle_GEOTRC (bottle data only), depth_GEOTRC_CTD (bottle data only), depth_GEOTRC_CTD_rounded (bottle data only), BTL_ISO_DateTime_UTC (bottle data only), and GeoFish_id (GeoFish data only). 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_GT10, GT-C_Bottle_GT11, ODF_Bottle_GT10, and ODF_Bottle_GT11 datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the Event_Log_GT10 and Event_Log_GT11 datasets. McLane pump cast numbers missing in event logs were taken from the Particulate Th-234 dataset submitted by Ken Buesseler.

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 deployment

Funding

Award Number	Funding Source
OCE-0927274	NSF Division of Ocean Sciences
OCE-0928191	NSF Division of Ocean Sciences
OCE-1132480	NSF Division of Ocean Sciences
OCE-1132515	NSF Division of Ocean Sciences

Instruments

Cold Vapor Atomic Fluorescence Spectrophotometer

Supplied Description:

Tekran Model 2500 CVAFS Mercury Detector

Instrument Type

Generic Name: Cold Vapor Atomic Fluorescence Spectrophotometer

Acronym: 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.

McLane Pump

Supplied Description:

Instrument Type

Generic Name: McLane Pump

Generic Description:

McLane pumps sample large volumes of seawater at depth. They are attached to a wire and lowered to different depths in the ocean. As the water is pumped through the filter, particles suspended in the ocean are collected on the filters. The pumps are then retrieved and the contents of the filters are analyzed in a lab.

Trace Metal Bottle

Supplied Description:

ODF (Scripps Ocean Data Facility) rosette with twelve 30-liter Niskin bottles

Instrument Type

Generic Name: Trace Metal Bottle

Acronym: TM Bottle

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/30/

Generic Description:

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

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise_id	Official cruise identifier e.g. KN199-04 = R/V Knorr cruise number 199-04.	text	cruise_id
cruise_part	identifier for a segment of a leg of a cruise, where a leg may have been broken into parts: For KN204-01: part A = 11/6/2011 to 11/18/2011 (Woods Hole to Bermuda) part B = 11/19/2011 to 12/11/2011 (Bermuda to Praia, Cabo Verde)	text	cruise_part
station_GEOTRC	GEOTRACES station number; ranges from 1 through 12 for KN199-04 and 1 through 24 for KN204-01. Stations 7 and 9 were skipped on KN204-01. PI-supplied values were identical to those in the intermediate US GEOTRACES master file. Originally submitted as 'sta', this parameter name has been changed to conform to BCO-DMO's GEOTRACES naming conventions.	integer	station
sample_GEOTRC	Unique identifying number for US GEOTRACES samples; ranges from 5033 to 6078 for KN199-04 and from 6112 to 8148 for KN204-01. 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
lat	latitude; north is positive	decimal degrees	lat
lon	longitude; east is positive	decimal degrees	lon
depth_n	nominal sample depth; provided in original data submission.	meters	depth_n
Hg_total	concentration of total mercury	picomoles/liter	trace_metal_conc
Hg_total_flag	total mercury quality flag: 2) ok 3) questionable 4) bad analysis 5) sample lost 6) mean of replicates 9) sample was not collected for Hg analysis	integer	flag
MMHg	concentration of monomethylmercury	femtomoles/liter	trace_metal_conc
MMHg_flag	monomethylmercury quality flag: 2) ok 3) questionable 4) bad analysis 5) sample lost 6) mean of replicates	integer	flag
comment	comment pertaining to sample.		comment
cast_GEOTRC	Cast identifier numbered consecutively within a station. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	dimensionless	cast
event_GEOTRC	Unique identifying number for US GEOTRACES sampling events; ranges from 2001 to 2225 for KN199-04 events and from 3001 to 3282 for KN204-01 events. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	dimensionless	event
sample_bottle_GEOTRC	Unique identification numbers given to samples taken from bottles; ranges from 1 to 24; often used synonymously with bottle number. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	dimensionless	bot_Nis
bottle_GEOTRC	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).	dimensionless	bottle
depth_GEOTRC_CTD	Observation/sample depth in meters; calculated from CTD pressure. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	meters	depth
BTL_ISO_DateTime_UTC	Date and time (UTC) variable recorded at the bottle sampling time in ISO compliant format. Values were added from the intermediate US GEOTRACES master file (see Processing Description). This standard is based on ISO 8601:2004(E) and takes on the following form: 2009-08-30T14:05:00[.xx]Z (UTC time)	YYYY-MM-DDTHH:MM:SS[.xx][+/-TZ]	ISO_DateTime_UTC

Database

Contribute Data

Dataset: GT10-11 - Hg Particulate
Deployment: KN204-01

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: GT10-11 - Hg ParticulateDeployment: KN204-01

Dataset acquisition description

Dataset Processing Description

Dataset: GT10-11 - Hg Particulate
Deployment: KN204-01