Dataset: GT10 - As AP Surface Transects
Deployment: KN199-05

Surface transects for arsenic speciation, antimony speciation, and alkaline phosphatase activity

Principal Investigator:

Gregory A. Cutter (Old Dominion University, ODU)

Contact:

Oliver Wurl (Old Dominion University, ODU)

BCO-DMO Data Manager:

Stephen R. Gegg (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Theresa McKee (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:

03 January 2013

Deployment Synonyms:

GA03, GT10, USGT-NAT-2010, KN199-5, GNAT, knorr199-4/5

Version Date:

2013-01-03

Data URL:

https://www.bco-dmo.org/dataset-deployment/454767/data

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Description

Data for the concentrations of the dissolved (<0.4 µm) arsenic species: total inorganic As (III+V), arsenite (AsIII), arsenate (AsV), monomethyl As, and dimethyl As; and the activity of the enzyme alkaline phosphatase (unfiltered) on the surface transect.

Modification history: Data were updated 3 January 2013

Please note that some US GEOTRACES data may not be final, pending intercalibration results and further analysis. If you are interested in following changes to US GEOTRACES NAT data, there is an RSS feed available via the BCO-DMO US GEOTRACES project page (http://www.bco-dmo.org/project/2066; scroll down and expand the "Datasets" section).

Methods & Sampling

Dataset acquisition description

Filtered (0.4 µm) water samples from the Geotraces surface tow-fish taken at discrete times into 500 mL Teflon FEP bottles, refrigerated, and analyzed within 24 hours of collection. Arsenic and antimony speciation determined using selective hydride generation, liquid nitrogen-cooled trapping, and then revolatilization and determination with gas chromatography/photoionization detection (Cutter et al., 1991; Cutter and Cutter, 2006). Calibration performed daily via the standard additions method, with a minimum of 4 additions of AsIII, AsV, MMAs, or DMAs depending on the analyses. The slope from the linear fit to these data was then applied to all samples for that day. Detection limits were 25 pmol/L for As(III) and As(III+V), and 50 pmol/L for MMAs and DMAs. Precision was better than 8% (relative standard deviation) for all As species. Alkaline phosphatase enzyme activity was measured using the fluorescence method of Ammerman (1993).

Data Processing Description

Dataset Processing Description

Samples analyzed in duplicate or triplicate and means computed.

BCO-DMO Processing Notes
- Generated from original .xls file "GEOTRACES Knorr 199-4 and -5 As Sb AP.xls" contributed by Greg Cutter
- cruise id converted to official UNOLS cruise id
- Year,Month,Day combined into Date and reformatted as YYYYMMDD
- Hour,Minute combined into Time and reformatted as HHMM
- "nd" (no data) value inserted in blank cells
- Parameter names modified to conform to BCO-DMO convention

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-0926092	NSF Division of Ocean Sciences
OCE-0926423	NSF Division of Ocean Sciences

Instruments

Gas Chromatograph

Supplied Description:

(tbd)

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)

GeoFish Towed near-Surface Sampler

Supplied Name: UCSC designed "GeoFish" towed sampling system

Supplied Description:

Surface seawater samples were collected from ~2-5 meters depth outside of ship's influence using the UCSC designed "GeoFish" towed sampling system.

All surface samples were filtered and then homogenized in one or two of the 500 L SAFe tanks

GeoFish/SAFe tank system consists of PFA Teflon^TM tubing, an all PFA Teflon^TM diaphragm pump, sequential filtration through 0.45 µm then 0.2 µm pore size polycarbonate, track etched (PCTE) pleated filter cartridges and two 500 L fluorinated low density polyethylene tanks connected with all Teflon^TM tubing, valves and fittings. All filtrations, acidifications and bottling of the SAFe and GEOTRACES samples were performed inside of Class-100 clean benches in a portable clean van.

Instrument Type

Generic Name: GeoFish Towed near-Surface Sampler

Acronym: GeoFish

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/31/

Generic Description:

The GeoFish towed sampler is a custom designed near surface (<2m) sampling system for the collection of trace metal clean seawater. It consists of a PVC encapsulated lead weighted torpedo and separate PVC depressor vane supporting the intake utilizing all PFA Teflon tubing connected to a deck mounted, air-driven, PFA Teflon dual-diaphragm pump which provides trace-metal clean seawater at up to 3.7L/min. The GeoFish is towed at up to 13kts off to the side of the vessel outside of the ship's wake to avoid possible contamination from the ship's hull. It was developed by Geoffrey Smith and Ken Bruland (University of California, Santa Cruz).

towed undulating vehicle

Supplied Description:

Instrument Type

Generic Name: towed undulating vehicle

Acronym: TUV

Generic Description:

A towed undulating vehicle is a generic class of instruments. See the data set specific information for a detailed description. These are often prototype instrument packages designed to make very specific measurements.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise_id	cruise id	text	cruise_id
transect_station	station identifier within transect	text	transect_station
date	Date in the format YYYYMMDD	unitless	date
time	Time	HHMM	time
lat	Latitude (South is negative)	decimal degrees	lat
lon	Longitude (West is negative)	decimal degrees	lon
AsIII	Arsenite (HAsO32-)	nmol/L	no_bcodmo_term
TAs	Total inorganic arsenic (AsIII+V)	nmol/L	no_bcodmo_term
MMAs	Monomethyl arsenic	nmol/L	no_bcodmo_term
DMAs	Dimethyl arsenic	nmol/L	no_bcodmo_term
AP_Turnover_Time	Alkaline phosphatase turnover time	hours	no_bcodmo_term
AP_Turnover_Rate	Alkaline phosphatase turnover rate	h-1	no_bcodmo_term
As	As(V)	nanomoles/liter	As

Database

Contribute Data

Dataset: GT10 - As AP Surface Transects
Deployment: KN199-05

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: GT10 - As AP Surface TransectsDeployment: KN199-05

Dataset acquisition description

Dataset Processing Description

Dataset: GT10 - As AP Surface Transects
Deployment: KN199-05