AMT15 aerosol sample isotopic composition of iron
Originator's Protocol for Data Acquisition and Analysis
Atmospheric sampling was conducted on the vessel's monkey island when wind conditions permitted, i.e. apparent wind direction was forward of the monkey island to ensure no contamination from the ship's stacks. A high volume air sampling system (approx. 1.7 m 3 min -1 ) was connected to a filter pack system, where samples of aerosol iron were collected on acid washed filters (Whatmann 41). Filters were changed under uniform light conditions in a laminar flow clean bench housed in a trace metal-clean laboratory. Filters were sealed in individual zip-lock plastic bags immediately after collection and stored frozen until analysis (Baker et al. 2006).
Total and soluble iron were extracted from fractions of the aerosol samples. Soluble iron was extracted using an ammonium acetate leach at pH 4.7 for 1-2 hours and total iron was extracted by acid digestion in HF/HNO3. The isotope ratio measurements were performed on a VGi Isoprobe Multi Collector Collision Cell Inductively Coupled Plasma Mass Spectrometer (MC-CC-ICPMS) (Waeles et al. 2007).
References Cited
Baker A.R., Jickells T.D., Witt M. and Linge K.L., 2006. Trends in the solubility of iron, aluminium, manganese and phosphorus in aerosol collected over the Atlantic Ocean. Marine Chemistry, 98, 43-58.
Waeles M., Baker A.R., Jickells T. and Hoogewerff J., 2007. Global dust teleconnections: aerosol iron solubility and stable isotope composition. Environmental Chemistry, 4, 233-237.
Instrumentation Description
Not relevant to this data set.
BODC Data Processing Procedures
Data were submitted via email in an Excel spreadsheet archived under BODC's accession number UEA090198. The file contained the following metadata columns: Start and end Date, time, latitude and longitude for each sample.
The aerosol ammonia data were provided in nanomoles per m -3 . These units are consistent with the BODC parameter code units and no conversions were necessary.
The data were reformatted and loaded in BODC's samples database under Oracle Relational Database Management System with the supplied metadata. Data were marked up with BODC parameter codes and loaded into the database.
A parameter mapping table is provided below;
| Originator's Parameter | Units | Description | BODC Parameter Code | Units | Comments |
|---|---|---|---|---|---|
| del56Fe_sol | Parts per thousand | Enrichment of iron-56 (soluble) {56Fe} in the atmosphere [aerosol phase] by filtration, leaching with pH 4.7 ammonium acetate buffer and inductively-coupled plasma mass spectrometry | ATFE56S1 | Parts per thousand | n/a |
| del56Fe_sol_SD | Parts per thousand | Enrichment standard deviation of iron-56 (soluble) {56Fe} in the atmosphere [aerosol phase] by filtration, leaching with pH 4.7 ammonium acetate buffer and inductively-coupled plasma mass spectrometry | ATFE56SD | Parts per thousand | n/a |
| del57Fe_sol | Parts per thousand | Enrichment of iron-57 (soluble) {57Fe} in the atmosphere [aerosol phase] by filtration, leaching with pH 4.7 ammonium acetate buffer and inductively-coupled plasma mass spectrometry | ATFE57S1 | Parts per thousand | n/a |
| del57Fe_sol_SD | Parts per thousand | Enrichment standard deviation of iron-57 (soluble) {57Fe} in the atmosphere [aerosol phase] by filtration, leaching with pH 4.7 ammonium acetate buffer and inductively-coupled plasma mass spectrometry | ATFE57SD | Parts per thousand | n/a |
| del56Fe_Total | Parts per thousand | Enrichment of iron-56 (total) {56Fe} in the atmosphere [aerosol phase] by filtration, acid digestion and inductively-coupled plasma mass spectrometry | AFE56TOT | Parts per thousand | n/a |
| del56Fe_Total_SD | Parts per thousand | Enrichment standard deviation of iron-56 (total) {56Fe} in the atmosphere [aerosol phase] by filtration, acid digestion and inductively-coupled plasma mass spectrometry | AFE56SDT | Parts per thousand | n/a |
| del57Fe_Total | Parts per thousand | Enrichment of iron-57 (total) {57Fe} in the atmosphere [aerosol phase] by filtration, acid digestion and inductively-coupled plasma mass spectrometry | AFE57TOT | Parts per thousand | n/a |
| del57Fe_Total_SD | Parts per thousand | Enrichment standard deviation of iron-57 (total) {57Fe} in the atmosphere [aerosol phase] by filtration, acid digestion and inductively-coupled plasma mass spectrometry | AFE57SDT | Parts per thousand | n/a |
Data Quality Report
The data originator indicated the sample collected 2/10/2004-3/10/2004 and analysed for total iron may have been contaminated and these data have been flagged 'L' in the database.
Problem Report
Not relevant to this data set.
