CTD samples of nutrients collected on cruise D245 along Extended Ellett Line
Originator's Protocol for Data Acquisition and Analysis
Samples for the analysis of dissolved inorganic nutrients (silcate, nitite and nitrate, and phosphate) were collected from the Niskin bottles after oxygen samples has been taken. The nutrient analysis was performed using a segmented flow 'AAII' type auto-analyser. Further details are in the cruise report, pages 33 to 36 and in Hydes, 1984.
References Cited
Holley, S.E., 1998. Report on the maintenance, precision and accuracy of measurements of dissolved inorganic nutrients and dissolved oxygen over 43 days of measurements on Cruise 230 'FOUREX' (07 Aug - 19 Sep 1997). SOC internal document No. 30, 34 pp.
Hydes, D.J.,1984. A manual of methods for the continuous flow determination of nutrients in seawater. IOSDL Report 177, 40 pp.
Murphy, J. and J.P. Riley, 1954. A modified single solution method for the determination of phosphate in natural waters. Anal. Chem. Acta. 27 p 31-66.
Instrumentation Description
The samples were taken with a CTD frame with 24 position rosette and 24 Niskin bottles. Nutrients were analysed with a Technicon AutoAnalyzer II colorimetric autoanalyser.
BODC Data Processing Procedures
Data received were loaded into the BODC database using established BODC data banking procedures.
The originator's pstar file (sam13786) appears to have data in the wrong columns for bottle (=sampnum) 10 to 15, specifically, values in the nitrate flag column should be in the silicate column, and values in the silicate column should be in the phosphate column. This is a reasonable guess based on the values, and was confirmed with data originator, Penny Holliday. When loading to the BODC database, it was noted that in the originator's pstar file (sam13773) bottle (=sampnum) 10, there was no value for pressure for this bottle, so the data from this bottle were discarded as the depth at which the sample was taken is unknown.
Parameters from the originator's source files were mapped to BODC parameter codes as follows:
| Originator's Parameter | Unit | Description | BODC Parameter Code | BODC Unit | Comments |
|---|---|---|---|---|---|
| no2+3 | µmol/l | Nitrate and nitrate from bottle sample determined by Auto Analyzer | NTRZAATX | Micromoles per litre | n/a |
| sio3 | µmol/l | Silicate from bottle sample determined by Auto Analyzer | SLCAAATX | Micromoles per litre | n/a |
| po4 | µmol/l | Phosphate from bottle sample determined by Auto Analyzer | PHOSAATX | Micromoles per litre | n/a |
Data Quality Report
No report provided by the originator, but information about data quality is included in the cruise report
Problem Report
No problem report.
