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Extended Ellett Line Inorganic Nutrient Data for RRS Discovery cruise D312

Originator's Data Acquisition and Analysis

Inorganic nutrients were measured on every bottle from every CTD cast following Sanders and Jickells (2000) using a Skalar San Plus autoanalyser equipped equipped with an all glass phosphate line. All data was processed in flow access version 1.04.4. In total 634 niskin bottle were analysed. Samples were drawn directly from niskin bottles into 25 ml sterilin polystyrene coulter counter vials, refrigerated in the dark at 4°C and analysed within 24 hours. Overall seventeen runs were carried out.

The instrument did not perform well on this trip despite the usual precautions being taken (washing the lines with 10 % Decon (N, Si) or Sodium Hydroxide (P), changing the tubes). Despite the various problems encountered all samples were analysed satisfactorily with the exception of phosphate from station 152.

BODC processing

The data were received in 64 pstar files which were loaded into the BODC database using established BODC data banking procedures without any changes.

The mapping between the originator's channels and BODC parameter codes is detailed in the table below.

Originator's Parameter Unit Description BODC Parameter Code BODC Unit Comments
NO3+NO2 Micromoles per litre Concentration of Nitrate + Nitrite {NO3+NO2} NTRZAATX Micromoles per litre n/a
PO4 Micromoles per litre Concentration of Phosphate {PO4} PHOSAATX Micromoles per litre n/a
SiO4 Micromoles per litre Concentration of Silicate SLCAAATX Micromoles per litre n/a

Data Quality Report

For a detailed QC analysis please see ( Cruise Report ) page 106.