K-axis dissolved iron (dFe) data from the Kerguelen-Axis region of the Southern Ocean

• Other Authors: SCHALLENBERG, CHRISTINA (hasPrincipalInvestigator), SCHALLENBERG, CHRISTINA (processor), BOWIE, ANDREW ROSS (hasPrincipalInvestigator), BOWIE, ANDREW ROSS (processor), Australian Antarctic Data Centre (publisher)
• Format: Dataset
• Language: unknown
• Published: Australian Antarctic Data Centre
• Subjects: oceans; NUTRIENTS; EARTH SCIENCE; OCEAN CHEMISTRY; TRACE ELEMENTS; GO-FLO BOTTLES; SHIPS; R/V AA > R/V Aurora Australis; R/V UM > R/V UMITAKA MARU; GEOGRAPHIC REGION > POLAR; CONTINENT > ANTARCTICA; OCEAN > SOUTHERN OCEAN > Banzare Bank; INDIAN OCEAN > KERGUELEN ISLANDS; Indian; Kerguelen; Kerguelen Islands; Southern Ocean; Antarc*; Antarctica; aurora australis
• Online Access: https://researchdata.ands.org.au/k-axis-dissolved-southern-ocean/1307185; https://doi.org/10.4225/15/5a77d6bd5975e; https://data.aad.gov.au/metadata/records/AAS_4344_dFe; http://nla.gov.au/nla.party-617536

Sampling was conducted according to GEOTRACES protocols. Samples for trace element analyses, including dissolved iron (dFe), were filtered through acid-cleaned 0.2 um cartridge filters (Pall Acropak) under constant airflow from several ISO class 5 HEPA units. All plastic ware was acid-cleaned prior to use, following GEOTRACES protocols. Samples were collected into low-density polyethylene (LDPE) bottles, acidified immediately to pH 1.7 with Seastar Baseline hydrochloric acid (HCl), double-bagged and stored at room temperature until analysis on shore. Samples for dFe analysis were pre-concentrated offline (factor 40) on a SeaFAST S2 pico (ESI, Elemental Scientific, USA) flow injection system with a Nobias Chelate-PA1 column. Samples were eluted from the column in 10% distilled nitric acid (HNO3), with calibration based on the method of standard additions in seawater (made using multi-element standards in a 10% HNO3 matrix, rather than an HCl matrix). Pre-concentrated samples were analysed using Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS, Thermo Fisher Scientific, Inc.). Data were blank-corrected by subtracting an average acidified milli-Q blank that was treated similarly to the samples. The dFe detection limit for a given analysis run on the SeaFAST/SF-ICP-MS was calculated as 3 x standard deviation of the milli-Q blank on that run. Detection limits ranged from 0.016 to 0.067 nmol kg-1, with a median of 0.026 nmol kg-1 (n=12). GEOTRACES reference materials were analyzed along with samples and results were in good agreement with consensus values: SAFe D1 was measured at 0.69 +/- 0.05 nmol kg-1 (n=7; consensus value = 0.67 +/- 0.04 nmol kg-1) and GD was measured at 1.02 +/- 0.01 nmol kg-1 (n=6; consensus value = 1.00 +/- 0.1 nmol kg-1). Comments regarding the data spreadsheet: NaN = no sample dFe QC flags: 1 = high confidence in data quality 2 = detection limit 3 = low confidence in data quality detection limits: dFe data that were below the daily detection limit were replaced with the respective detection limit. They are flagged with the number 2 in the dFe QC flag column.