Dissolved trace metals (Cu, Cd, Ni, Fe, Mn, Co, Pb and Zn) concentrations collected from a CTD and a towed FISH on the GEOTRACES JC086 cruise in the South Atlantic Ocean
Responsible investigator
Prof Gideon Henderson
Email: gideonh@earth.ox.ac.uk
University of Oxford
Department of Earth Sciences,
South Parks Road,
Oxford
OX1 3AN
Data contributors
Dr. Chistian Schlosser
email: cschlosser@geomar.de
GEOMAR Helmholtz Centre for Ocean Research
Wischhofstr. 1-3
24148 Kiel
Germany
Laboratory of analysis
NOC Southampton
Originator's Protocol for Data Acquisition and Analysis
Sample collection and Analysis
Dissolved seawater samples (0.2µm) from the South Atlantic along 40°S were collected during the UK GEOTRACES cruise JC068 in December 2011 and January 2012 using a trace metal clean titanium frame CTD. The CTD was attached to a Kevlar wire and deployed with a special winch. Niskin bottles were transferred in a clean room lab container. The seawater was filtered using AcroPak 500 polyethersulfone filters and dispensed in acid washed 125 mL low density polyethylene bottles.
Surface samples were also collected from each station by pumping surface seawater into a trace metal clean laboratory using a Teflon diaphragm pump (Almatec A-15, Germany) connected by an acid-washed braided PVC tubing to a towed fish positioned at approximately 2 - 3m depth alongside the ship. Seawater samples were filtered in-line using a 0.2 ìm AcroPak Supor membrane filter capsule (Pall). In between each station, surface seawater samples were collected on a 2 or 4 hourly interval. A total of 123 underway surface samples were collected.
The filtered seawater from both CTD's and the towed fish was acidified to pH1.9 and shipped to the NOC Southampton for farther analysis.
The filtered seawater samples were stored for a period of 12 months prior to analysis. Concentrations of dissolved trace metals in seawater were determined by off-line preconcentration and isotope dilution (ID) ICP-MS (ThermoFisher Scientific Element2 XR) for Cd, Pb, Fe, Ni, Cu, and standard addition ICP-MS for Mn and Co. The preconcentration and ICP-MS analysis was adapted from the method outlined by Milne et al. [2010]. In short, all samples were irradiated with strong ultraviolet light for 3.5 hours in order to remove metal complexing organic interferences. Subsequently, the sample solution was buffered to pH 6.4 using a 2 M ammonium acetate solution (pH 9.2, Fisher Optima grade ammonia and acetic acid, glacial). Immediately following buffer addition the solution was preconcentrated using a metal chelating resin (WAKO) [Kagaya et al., 2009] and 1 M sub-boiled HNO3 elution acid.
References Cited
Kagaya, S., E. Maebe, Y. Inoue, W. Kamichatani, T. Kajiwara, H. Yanai, M. Saito, and K. Tohda (2009). A solid phase extraction using a chelate resin immobilizing carboxymethylated pentaethylenehexamine for separation and preconcentration of trace elements in water samples, Talanta, 79, 146-152.
Milne, A., W. Landing, M. Bizimis, and P. Morton (2010). Determination of Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb in seawater using high resolution magnetic sector inductively coupled mass spectrometry (HR-ICP-MS), Anal. Chimi. Acta, 665(2), 200-207.
BODC Data Processing Procedures
Data were received in Microsoft Excel format and values were extracted for loading into BODC's ocean database under the ORACLE Relational Database Management System. BODC only received Zinc data from the towed fish.
The mapping between the originator's channels and the BODC parameter codes are detailed in the table below.
| Originator's Parameter | Unit | Description | BODC Parameter Code | BODC Unit | Comments |
|---|---|---|---|---|---|
| Cd | nmol/kg | Concentration of cadmium {Cd} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | CDCONICP | Nanomoles per kilogram | n/a |
| Cd standard deviation | nmol/kg | Concentration standard deviation of cadmium {Cd CAS 7440-43-9} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | CDSDKGI5 | Nanomoles per kilogram | n/a |
| Pb | nmol/kg | Concentration of lead {Pb CAS 7439-92-1} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | PBICPMS2 | Picomoles per kilogram | To convert from nanomoles to picomoles values were multiplied by 1000 |
| Pb standard deviation | nmol/kg | Concentration standard deviation of lead {Pb CAS 7439-92-1} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | PBSDICP6 | Picomoles per kilogram | To convert from nanomoles to picomoles values were multiplied by 1000 |
| Fe | nmol/kg | Concentration of iron (total) {Fe} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | FEICPMS2 | Nanomoles per kilogram | n/a |
| Fe standard deviation | nmol/kg | Concentration standard deviation of iron (total) {Fe} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | FESDKGI5 | Nanomoles per kilogram | n/a |
| Ni | nmol/kg | Concentration of nickel {Ni} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | NIICPMS2 | Nanomoles per kilogram | n/a |
| Ni standard deviation | nmol/kg | Concentration standard deviation of nickel {Ni} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | NISDKGI5 | Nanomoles per kilogram | n/a |
| Cu | nmol/kg | Concentration of copper {Cu CAS 7440-50-8} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | CUICPMS2 | Nanomoles per kilogram | n/a |
| Cu standard deviation | nmol/kg | Concentration standard deviation of copper {Cu CAS 7440-50-8} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | CUSDKGI5 | Nanomoles per kilogram | n/a |
| Mn | nmol/kg | Concentration of total manganese {total_Mn CAS 7439-96-5} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | MNICPMS2 | Nanomoles per kilogram | n/a |
| Mn standard deviation | nmol/kg | Concentration standard deviation of total manganese {total_Mn CAS 7439-96-5} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | MNSDKGI5 | Nanomoles per kilogram | n/a |
| Co | nmol/kg | Concentration of cobalt {Co CAS 7440-48-4} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | COICPMS2 | Picomoles per kilogram | To convert from nanomoles to picomoles values were multiplied by 1000 |
| Co standard deviation | nmol/kg | Concentration standard deviation of cobalt {Co CAS 7440-48-4} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | COICPMSD | Picomoles per kilogram | To convert from nanomoles to picomoles values were multiplied by 1000 |
| Zn | nmol/kg | Concentration of zinc {Zn CAS 7440-66-6} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | ZNICPMS2 | Nanomoles per kilogram | n/a |
| Zn standard deviation | nmol/kg | Concentration standard deviation of zinc {Zn CAS 7440-66-6} per unit mass of the water body [dissolved plus reactive particulate <0.2um phase] by filtration, acidification and inductively-coupled plasma mass spectrometry | ZNSDKGI5 | Nanomoles per kilogram | n/a |
Data Quality Report
The cadmium channel reported a value below detection on CTD cast 60 niskin 17 and so BODC have flagged this value as below the detection limit '<'.
