Dataset: GN01 Particulate Mercury

Name: Particulate total mercury and particulate monomethylmercury concentrations from the Western Arctic Ocean, which were sampled by McLane pumps during he 2015 US GEOTRACES Cruise (GN01; HLY1502)
Published: 2018-07-10
License: https://creativecommons.org/licenses/by/4.0/
Keywords: oceans

View Data: Data not available yet

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Spatial Extent: N:89.997 E:11.9102 S:60.224 W:178.927

Temporal Extent: 2015-08-12 - 2015-10-08

Project:

Collaborative Research: GEOTRACES Arctic Section: Mercury Speciation and Cycling in the Arctic Ocean (GEOTRACES Arctic Mercury)

U.S. Arctic GEOTRACES Study (U.S. GEOTRACES Arctic)

Principal Investigator:

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

Co-Principal Investigator:

Chad Hammerschmidt (Wright State University)

Contact:

Alison Agather (Wright State University)

BCO-DMO Data Manager:

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

Version Date:

2018-07-10

Restricted:

Release Date:

2018-09-15

Validated:

Yes

Current State:

Under revision

Particulate total mercury and particulate monomethylmercury concentrations from the Western Arctic Ocean, which were sampled by McLane pumps during he 2015 US GEOTRACES Cruise (GN01; HLY1502)

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Description

This dataset includes particulate total mercury and particulate monomethylmercury concentrations from the Western Arctic Ocean, which were sampled as part of the 2015 US GEOTRACES Cruise (GN01; HLY1502). Samples were collected with McLane pumps, size fractionated between 1 and 51 um.

Status note (2019-11-12): These data are currently under revision.

Acquisition Description

Sample collection with in-situ pumps is outlined in Bishop et al. 2012.

Particulate samples were frozen and transported to Wright State University (Dayton, OH) where they were analyzed within 6 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, according to Hammerschmidt & Fitzgerald (2006). All analyzes were performed on Tekran Model 2500 CVAFS Mercury Detector.

Particulate HgT analysis was done according to Fitzgerald & Gill (1979), Bloom & Fitzgerald (1988), and Bloom (1989). The method detection limit was 0.75 pmol/kg, and procedural duplicates averaged 7 ± 6 RPD (n = 16).

Particulate MMHg was analyzed according to Tseng et al. (2004). The detection limit for the method was 0.075 pmol/kg.

While at sea, variable gas pressure in the gas chromatograph caused irregular MMHg peak retention times, making it indecipherable from the inorganic Hg peak. Accordingly, seawater samples ranging from 0.25 to 2 L, were acidified to 1% with sulfuric acid and shipped frozen to Wright State University for analysis.

Processing Description

WOCE Quality Flags:
2 – Ok,
3 – Questionable,
4 – Bad Analysis,
5 – Sample lost,
6 – Mean of replicates,
9 – Sample was not collected for Hg analysis.

"nd" indicates no data.
"bdl" indicates below detection limit.

BCO-DMO Processing:
- separated cruise column into two: cruise_name and cruise_id;
- modified parameter names; applied GEOTRACES names provided by submitter;
- corrected HLY cruise ID number (they were incrementing by one for each row). - joined the following columns from HLY1502 event log, based on the GEOTRC_SAMPNO: GETORC_EVENTNO, GEOTRC_INSTR, ISO_DATETIME_UTC_START_EVENT, ISO_DATETIME_UTC_END_EVENT, EVENT_LAT, EVENT_LON, CASTNO.
- 30-Oct-2018: removed embargo on dataset.
- 21-Oct-2019: corrected units of measurement for Hg_SPT_CONC_PUMP and HG_MM_SPT_CONC_PUMP in parameter defintions section of metadata. These were previously labeled as picomolar but values are reported in pmol/kg.

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1434650
NSF Division of Ocean Sciences	OCE-1434653
NSF Division of Ocean Sciences	OCE-1534315

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
HLY1502	GN01 U.S. GEOTRACES Arctic	2015-08-09	USCGC Healy	David C. Kadko (Chief Scientist) William M. Landing (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: Cold Vapor Atomic Fluorescent Spectrometer (CVAFS)

Dataset-specific description

Cold Vapor Atomic Fuorescent Spectrometer (CVAFS) quantitatively measures volatile heavy metals, such as mercury. Gaseous mercury atoms are carried to the detector via inert gas, excited by a UV light source, and radiate the absorbed energy. The fluorescence is detected by either a photomultiplier tube or UV photodiode.

McLane Pump

(more info)

Short 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.

PI supplied instrument name: McLane in-situ pump

Dataset-specific description

McLane in-situ pumps were used to collect the 1–51 μm size fractioned samples.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise_name	Cruise identification	unitless	cruise_name
cruise_id	Official cruise ID	unitless	cruise_id
GEOTRC_INSTR	Sampling instrument; joined from event log	unitless	instrument
GEOTRC_EVENTNO	GEOTRACES event number; joined from event log	unitless	event
STNNBR	GEOTRACES station number	unitless	station
CASTNO	Cast number; joined from event log	unitless	cast
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	unitless	ISO_DateTime_UTC
ISO_DATETIME_UTC_END_EVENT	Date and time, formatted to the ISO 8601 standard, at the end of the sampling event, according to the event log. Format: YYYY-MM-DDTHH:MM:SS[.xx]Z	unitless	ISO_DateTime_UTC
Latitude	Latitude of sample collection; provided by the data contributor	decimal degrees north	lat
Longitude	Longitude of sample collection; provided by the data contributor	decimal degrees east	lon
EVENT_LAT	Latitude at the start of the event; north is positive; joined from event log	decimal degrees	lat
EVENT_LON	Longitude at the start of the event; east is positive; joined from event log	decimal degrees	lon
GEOTRC_SAMPNO	GEOTRACES sample number	unitless	sample
Depth	Depth of sample collection; provided by the data contributer	meters (m)	depth
Hg_SPT_CONC_PUMP	Total mercury measurement	picomoles per kilogram (pmol/kg)	trace_metal_conc
Hg_SPT_CONC_PUMP_QF	Total mercury quality flag (WOCE)	unitless	q_flag
HG_MM_SPT_CONC_PUMP	Monomethylmercury measurement	picomoles per kilogram (pmol/kg)	trace_metal_conc
HG_MM_SPT_CONC_PUMP_QF	Monomethylmercury quality flag (WOCE)	unitless	q_flag
comment	Comments	unitless	comment

Database

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Dataset: GN01 Particulate Mercury