AMT15 underway sampled Particulate Inorganic Carbon (PIC), Biological Silica (BSi) and Particulate Organic Carbon (POC)
Data Acquisition and Analysis
This data originates from analyses on samples collected from the ship's non-toxic supply during the AMT15 cruise. Water samples were collected every 3-6 hours during the cruise from the ship's non-toxic supply. PIC was collected from 1 litre of seawater by vacuum filtration onto a 0.45 µm cellulose nitrate filter. The filters were then rinsed with potassium tetraborate buffer and stored in individual cryo vials at room temperature for the remainder of the cruise. BSi was collected from 1 litre of seawater by vacuum filtration onto a 0.4 µm polycarbonate filter, which were then stored in scintillation vials at -20 o C for the duration of the cruise. POC was measured by filtering water samples (2-4 litres) through pre-combusted (400 o C) glass-fibre filters.
PIC: After the cruise the samples were analysed using inductively coupled plasma atomic emission spectrometry (ICPAES).
BSi: After the cruise the residue on the filter paper was dissolved in 2.5 ml sodium hydroxide and then the solution was neutralised with 0.1 mol L -1 hydrochloric acid and the Si concentration was measured using a flow autoanalyser.
POC: Filters were acid fumed to remove calcite contamination and analysed using a Thermo Finnegan Flash EA1112 Elemental Analyser (Poulton et al. , 2007).
References Cited
Poulton A.J., Adey T.R., Balch W.M., and Holligan P., 2007. Relating coccolithophore calcification rates to phytoplankton community dynamics: regional differences and implications for carbon export. Deep-Sea Research Part II, 54(5-7), 538-557.
Instrumentation Description
Not relevant to this dataset.
BODC Data Processing Procedures
Data were submitted to BODC in a tab delimited text format and accession under BODC archive BGL060512. Sample metadata were checked against information held in the database - there were no significant discrepancies. The depth for the samples was logged as 5 m, which matched the database records for underway chl-a samples. The were rplicates for sample BF which the mean value was loaded to the database.
Parameter codes defined in the BODC parameter dictionary were assigned to the variables. The data for PIC and POC were converted from mg m -3 to µmol L -1 , this was achieved by dividing by 12 (atomic mass of carbon) and the BSi data were provided in units (mmol m -3 ), which were consistent with those used in the BODC database for the parameter codes (µmol L -1 ).
Data loaded into BODC's database with only a unit conversion change applied.
A parameter mapping table is provided below;
| Originator's Parameter | Units | Description | BODC Parameter Code | Units | Comments |
|---|---|---|---|---|---|
| PIC | mg m -3 | Concentration of carbon (inorganic) {PIC} per unit volume of the water body [particulate >0.4µm phase] by filtration, acid digestion and inductively-coupled plasma atomic emission spectroscopy | CINGFA04 | µmol l -1 | Unit conversion of x1/12 applied to data |
| BSi | mmol m -3 | Concentration of biogenic silica {opal} per unit volume of the water body [particulate >0.4um phase] by filtration, alkali hydrolysis and colorimetric analysis | OPALWCP4 | µmol l -1 | n/a |
| POC | mg m -3 | Concentration of carbon (organic) {POC} per unit volume of the water body [particulate >GF/F phase] by filtration, acidification and elemental analysis | CORGCAP1 | µmol l -1 | Unit conversion of x1/12 applied to data |
Data Quality Report
BODC were not advised of specific quality checks carried out by the data originators.
Problem Report
Not relevant to this dataset.
