Dataset: GP16 Elemental selenium and particulate Acid-Volatile Sulfide
Deployment: TN303

Particulate Acid-Volatile Sulfide (pAVS) and elemental Selenium (pSe) depth profiles from McLane pump

Principal Investigator:

Gregory A. Cutter (Old Dominion University, ODU)

Contact:

Gregory A. Cutter (Old Dominion University, ODU)

BCO-DMO Data Manager:

Ms Dicky Allison (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Amber D. York (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

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

US GEOTRACES Pacific section: Characterizing the redox environment of the eastern tropical Pacific Ocean (EPZT_Redox_Elements)

Current State:

Final no updates expected

Version:

Deployment Synonyms:

GP16, GEOTRACES EPZT, GEOTRACES East Pacific Zonal Transect (EPZT), GT13, 325020131025

Version Date:

2016-05-20

Data URL:

https://www.bco-dmo.org/dataset-deployment/646154/data

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Description

Data for the concentrations of Particulate Acid-Volatile Sulfide (pAVS) (0.8 mm) in depth profiles from in situ McLane pumps at GEOTRACES EPZT Stations 1-5, 7, 9, 11, 13, 17, 18, 20, 21, and 23.

DMO notes:

changed -9999 values in SAMPNO to nd
added zeros to pad EVENT_LAT and EVENT_LON where decimal places were not 5 places like most of the dataset.
orginal name pAVS and pSe(0) changed to conform to GEOTRACES conventions

Methods & Sampling

Dataset acquisition description

Samples analyzed for acid-volatile sulfides (AVS) were collected on McLane pumps suspended from a trace metal wire (Hytrel-jacketed Vectran). Pumps filtered for four hours, flowing first over a 51-µm polyester pre-filter, then over paired 0.8-µm pore-size, 142-mm Supor polyethersulfone filters. A small portion of the top Supor filter, representing ~2% of the filter area (0.8-51 µm size-fraction material), was sub-sectioned into polyethylene vials and frozen at -85˚C until shipboard AVS analysis, described below. Filter blanks were held within identical filter housings and submerged on one of the deeper pumps on each cast, but were not actively filtered through. Blanks were handled identically to samples during processing, which was conducted in a HEPA-filtered environment using trace metal procedures.

Particulate elemental samples were collected using McLane in situ pumps (P. Lam, UCSC) with splits (section) from a 0.8 µm Supor filter processed immediately in a N₂-purged glove bag after collection and pump recovery; filter splits were placed and sealed in Tedlar bags and stored at -80°C until analysis. Particulate elemental selenium concentrations were determined using a sulfite leach following Velinsky and Cutter (1990) and analyzed like selenite+selenate following Cutter (1978). Precision was ca. 10% RSD (n=3).

Data Processing Description

Dataset Processing Description

Samples analyzed in triplicate and means computed. Standard additions of selenite were used for daily calibration on a representative sample and its slope applied to subsequent samples.

Determinations of acid-volatile sulfide (AVS) were made on-board ship and used the method of Cutter and Oatts (Cutter and Oatts, 1987) that includes acidification, gas stripping and cryogenic trapping/preconcentration of the generated hydrogen sulfide. In this case, the filter slice was placed in a glass stripping vessel, 10 mL of deionized water added, and the stripper purged with He. The cryogenic trap was then immersed in liquid nitrogen, 10mL of 1M HCl added through a septum in the stripping vessel and the evolved and trapped hydrogen sulfide was then quantified using the gas chromatography/flame photometric detection method of Radford-Knoery and Cutter (Radford-Knoery and Cutter, 1993). The system was calibrated with hydrogen sulfide from a permeation tube (calibrated diffusion rate) and assuming a filtration volume of at least 5L (median sample volume: 7.9L), the detection limit was 0.2 pmol/L. It should be noted that AVS determined by this method includes monosulfides of iron, zinc, and nickel, but not those with copper or mercury, or mixed oxidation state sulfides such as greigite or pyrite (Cutter and Oatts, 1987; Radford-Knoery and Cutter, 1993).

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-1235328	NSF Division of Ocean Sciences

Instruments

Gas Chromatograph

Supplied Name: Gas chromatograph

Supplied Description:

Gas chromatograph/flame photometric ionizer

Instrument Type

Generic Name: Gas Chromatograph

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB02/

Generic Description:

Instrument separating gases, volatile substances, or substances dissolved in a volatile solvent by transporting an inert gas through a column packed with a sorbent to a detector for assay. (from SeaDataNet, BODC)

McLane Pump

Supplied Name: McLane pumps

Supplied Description:

In the data, McLane pumps are called "McL-Prof."

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.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise_id	Cruise identifier. TN = R/V Thomas G. Thompson.	unitless	cruise_id
GEOTRC_EVENTNO	GEOTRACES event number.	unitless	event
CASTNO	Cast number.	unitless	cast
DATE_START_EVENT	Date at the start of the event, according to the event log. in the format YYYYmmdd	unitless	date_start
ISO_DATETIME_UTC_START_EVENT	Date and time (UTC) at start of the event, formatted to ISO 8601 standard, according to the event log. Format is YYYY-mm-ddTHH:MM:SS.xxZ.	unitless	ISO_DateTime_UTC
EVENT_LAT	Latitude at the start of the event, according to the event log.	decimal degrees	lat
GEOTRC_SAMPNO	GEOTRACES sample number.	unitless	sample
SAMPNO	Bottle sample number, according to PI.	unitless	sample
STNNBR	Station number.	unitless	station
EXPOCODE	Used as a unique identifier for a cruise. Usual generation formula is ICES 4 character platform code then the cruise departure date in YYYYMDD format	unitless	EXPOCODE
SECT_ID	GEOTRACES cruise name.	unitless	cruise_name
TIME_START_EVENT	Time at the start of the event according to the event log	unitless	time_start
DEPTH_MIN	event depth minimum	meters	depth_min
DEPTH_MAX	event depth maxium	meters	depth_max
depth_n	nominal depth	meters	depth_n
AVS_TP_CONC_PUMP	particulate acid volatile sulfide	picomoles per liter	trace_element_conc
Se_0_TP_CONC_PUMP	particulate elemental selenium	nanomoles per liter	trace_element_conc
EVENT_LON	Longitude according to the event log; West is negative	decimal degrees	lon
GEOTRC_INSTR	Instrument	unitless	instrument

Database

Contribute Data

Dataset: GP16 Elemental selenium and particulate Acid-Volatile Sulfide
Deployment: TN303

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: GP16 Elemental selenium and particulate Acid-Volatile SulfideDeployment: TN303

Dataset acquisition description

Dataset Processing Description

Dataset: GP16 Elemental selenium and particulate Acid-Volatile Sulfide
Deployment: TN303