AMT6 iron and trace metal concentrations from CTD bottle samples
Originator's Protocol for Data Acquisition and Analysis
This data originates from analyses on samples collected from 28 stations during the cruise.
Samples were collected during the upcast in 30l Go-Flo bottles, modified for trace metal sampling, and mounted on an epoxy paint-coated rosette frame. Each Go-Flo bottle was thoroughly acid cleaned prior to use. Seawater samples for trace metal analyses were taken immediately on retrieval of the Go-Flo samplers. The samples were stored prior to analysis in 250ml high density polyethylene (HDPE, Nalgene) bottles, which had been rigorously acid cleaned following standard protocols (Bruland et al. , 1979). All samples were unfiltered in order to minmise potential sample contamination from the filtration procedure.
Samples were immediately transferred to a dedicated clean area within the ship' laboratory and acidified to pH 2.0 with 250 µl of sub-boiling, quartz-distilled HCl (Q-HCl, 9.2 M) per 250 ml of sample. Samples collected for subsequent land-based analysis were acifdified and stored in the dark. Description of the analysis methods for dissolved iron and the trace metals can be found in Bowie et al. (2002)
References Cited
Bowie A.R., Whitworth D.J., Achterberg E.P., Mantoura R.F.C. and Worsfold P.J., 2002. Biogeochemistry of Fe and other trace elements (Al, Co, Ni) in the upper Atlantic Ocean. Deep-Sea Research I, 49, 605-636.
Bruland K.W., Franks R.P., Knauer G.A. and Martin J.H., 1979. Sampling and analysitical methods for the determination of copper, cadmium, zinc and nickel at the nanogram per litre level in seawater. Analytica Chimica Acta, 105, 233-245.
Instrumentation Description
Not applicable for this data set.
BODC Data Processing Procedures
Data were submitted with the AMT3 dissolved iron and trace metal dataset in an Excel spreadsheet archived under BODC's accession number PML020057. The AMT6 data were presented as surface and CTD data, however comparison of the datsets showed the surface dataset was a collection of the shallowest CTD bottle samples. Therefore only the CTD samples have been loaded to the database. Sample metadata (Station, CTD cast, date, Julian Day, latitude, longitude and depth) were checked against information held in the database. There were no discrepancies.
Where replicate samples were provided the average of the values were entered into the database.
The concentration data were provided in nanomoles per litre, except for the Cobalt concentration data which were provided in picomoles per litre. These units associated with the appropriate parameter in the BODC parameter library were nanomoles per litre, so a unit conversion was applied to only the Cobalt concentration data (x 10 -3 ).
The data were reformatted and loaded in BODC's samples database under Oracle Relational Database Management System. Data were marked up with BODC parameter codes and loaded into the database. Individual samples were matched by depth for each cast.
A parameter mapping table is provided below;
| Originator's Parameter | Units | Description | BODC Parameter Code | Units | Comments |
|---|---|---|---|---|---|
| TD-Fe (ship) | nmol l -1 | Concentration of iron (total) {Fe} per unit volume of the water body [dissolved plus reactive particulate phase] by flow-injection chemiluminescence | FEXXCLDX | nmol l -1 | n/a |
| TD-Al | nmol l -1 | Concentration of aluminium {Al} per unit volume of the water body [dissolved plus reactive particulate phase] by lumogallion fluorescence | ALXXLGTX | nmol l -1 | n/a |
| TD-Co | pmol l -1 | Concentration of cobalt {Co} per unit volume of the water body [dissolved phase] by UV digestion and cathodic stripping voltammetry | COXXCVDX | nmol l -1 | Unit conversion applied (x 10 -3 ) |
| TD-Ni | nmol l -1 | Concentration of nickel {Ni} per unit volume of the water body [dissolved phase] by UV digestion and cathodic stripping voltammetry | NIXXCVDX | nmol l -1 | n/a |
Data Quality Report
BODC were not advised of any quality control carried out by the data originator.
Problem Report
Not relevant to this data set.
