Metadata Report for BODC Series Reference Number 2293725

• Metadata Summary

• Problem Reports

• Data Access Policy

• Narrative Documents

• Project Information

• Data Activity or Cruise Information

• Fixed Station Information

• BODC Quality Flags

• SeaDataNet Quality Flags

Metadata Summary

Problem Reports

No Problem Report Found in the Database

Data Access Policy

Public domain data

These data have no specific confidentiality restrictions for users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."

Narrative Documents

Technicon AutoAnalyzer II (AAII)

The AAII is a segmented flow analyzer used for automated colorimetric analysis. The apparatus uses 2 mm diameter glass tubing and pumps reagents at flow rates of 2 to 3 ml s^-1, producing results at a typical rate of 30 to 60 samples per hour. The system comprises an autosampler, peristaltic pump, chemistry manifold a detector and a data acquisition software.

This instrument was replaced by the AA3 in 1997 which was upgraded to the AA3 HR systems in 2006.

Specifications

Niskin Bottle

The Niskin bottle is a device used by oceanographers to collect subsurface seawater samples. It is a plastic bottle with caps and rubber seals at each end and is deployed with the caps held open, allowing free-flushing of the bottle as it moves through the water column.

Standard Niskin

The standard version of the bottle includes a plastic-coated metal spring or elastic cord running through the interior of the bottle that joins the two caps, and the caps are held open against the spring by plastic lanyards. When the bottle reaches the desired depth the lanyards are released by a pressure-actuated switch, command signal or messenger weight and the caps are forced shut and sealed, trapping the seawater sample.

Lever Action Niskin

The Lever Action Niskin Bottle differs from the standard version, in that the caps are held open during deployment by externally mounted stainless steel springs rather than an internal spring or cord. Lever Action Niskins are recommended for applications where a completely clear sample chamber is critical or for use in deep cold water.

Clean Sampling

A modified version of the standard Niskin bottle has been developed for clean sampling. This is teflon-coated and uses a latex cord to close the caps rather than a metal spring. The clean version of the Levered Action Niskin bottle is also teflon-coated and uses epoxy covered springs in place of the stainless steel springs. These bottles are specifically designed to minimise metal contamination when sampling trace metals.

Deployment

Bottles may be deployed singly clamped to a wire or in groups of up to 48 on a rosette. Standard bottles and Lever Action bottles have a capacity between 1.7 and 30 L. Reversing thermometers may be attached to a spring-loaded disk that rotates through 180° on bottle closure.

CTD Rosette bottle micromolar nutrients (nitrate, nitrite, ammonium, phosphate and silicate) from JR19980114 (JR28)

Acquisition description:

Sampling methodology

Water samples were taken from a total of 39 lowered CTD (conductivity, temperature and depth) casts, during the James Clark Ross cruise JR19980114 (JR28) to the north of the Maurice Ewing Bank (MEB, South Atlantic Ocean), between the 14th of January and 7th of February 1998. The CTD unit used for the measurement program was the British Antarctic Survey (BAS) Neil Brown Mk IIIb (serial number 01 - 3838 - 1086). The CTD was mounted in a purpose built frame with a General Oceanics 12 position bottle rosette. A 10 litre General Oceanics sampling bottle was fitted on each position on the rosette, controlled via a General Oceanics RMS MKVI 1015 - PM controlling unit. The package was also fitted with a 10 kilohertz pinger to enable accurate near bottom approach.

Deployment of the CTD package was from the midships gantry and A-frame on a single conductor, torque balanced cable. This CTD cable was made by Rochester Cables and was hauled on the 10 tonne traction winch. There were no problems deploying the CTD package as close control was maintained with the gib arm, and two hand lines by the ship’s crew, whilst the package was suspended above the surface.

Analytical methodology

Discrete samples were collected from the CTD bottle rosette into a 60 millilitre syringe. Samples were then filtered through acid washed (10% Hydrochloric acid (HCL)) 0.45 micromole pore-size mixed ester filters, into 125 millilitre sample pots, for measurement of nitrate, nitrite, ammonium, phosphate and silicate. Chemical analyses were undertaken using a custom-built Segmented-Flow Analyser (Technicon Autoanalyser II colorimetric autoanalyser), based on Chemlab colorimeters and Ismatec proportioning pumps. Data acquisition and subsequent processing was achieved with custom-built software (BAS in-house and Cambridge Beacon Ltd). Data collected were logged along with a time-stamp acquired from the central ship's clock to allow synchronisation with concurrent measurements, such as temperature and salinity from the ship's Oceanlogger system. Chemical analysis was undertaken aboard ship using the Segmented-Flow Analyser and data analysis was performed post-cruise. Analyses were made of dissolved nutrients according to adaptations of the methods of; Brewer and Riley (1965) for nitrate, Grasshoff (1976) for nitrite, Mantoura and Woodward (1983) for ammonium, and Kirkwood (1989) for silicate and phosphate.

A Neil Brown MK3 CTD sensor (serial number 01 - 3838 - 1086) was used to determine vertical profiles of temperature and salinity at each station. The most recent calibration had been carried out by Ocean Scientific International from the 4th of July to the 6th of August 1997. Temperature and salinity from the respective water bottle firings on the upcast of the profile were matched to the nutrient data. Where these data were not available, measurements from the depth of the bottle firing (± 2 metres) on the downcast of the CTD were used instead. CTD data were logged using a Neil Brown Instrument Systems deck unit (model 1150), connected to a 386 Viglen PC, running the E.G. and G. Marine Instruments CTD data acquisition module (version 2.02) control software. Data were also logged to the RVS ABC system, through a dedicated microcomputer.

Further information on originator's processing can be found in the JR19980114 (JR28) cruise report and the originator's publication (Whitehouse et al., 2022).

References Cited

Brewer P.G. and Riley J.P., 1965. The automatic determination of nitrate in sea water. Deep Sea Research, 12, 765-72.

Grasshoff K., 1976. Methods of seawater analysis. Verlag Chemie, Weiheim and New York, 317pp.

Mantoura R.F.C and Woodward E.M.S, 1983. Optimization of the indophenol blue method for the automated determination of ammonia in estuarine waters. Estuarine Coastal and Shelf Science, 17, 219-24.

Kirkwood D., 1989. Simultaneous determination of selected nutrients in seawater. ICES CM 1989/C:29.

Whitehouse M., Hendry K., Tarling G., Thorpe S. and ten Hoopen P., 2022. Macronutrient, temperature and salinity measurements made around the island of South Georgia and the wider Scotia Sea, the Antarctic Peninsula, and in the Bellingshausen Sea between 1980 and 2009 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/4014370f-8eb2-492b-a5f3-6dc68bf12c1e

BODC Data Processing Procedures

Data received were loaded into the BODC database using established BODC data banking procedures. A parameter mapping table is provided below:

Data Quality Report

A drastic decline in the quality of deionized water, provided by the Elgastat UHP unit during the Western Core Box, caused difficulties with ammonium analyses. The deionized water eventually returned to an acceptable quality for ammonium determination, following renewal of the cartridges in the Elgastat and continued flushing of the unit. For the three days when water quality was poor, reference was made to low nutrient seawater blanks and standards.

Project Information

BAS Long Term Monitoring and Survey

Introduction

The Long Term Monitoring and Survey project (LTMS) has been running since the British Antarctic Survey (BAS) was created. This project is one of the BAS core projects, with several groups of scientists collecting various types of data e.g biological, geological, atmospheric, among others.

Data collection is achievable through a wide scope of instruments and platforms, e.g. the Antarctic research stations, autonomous instrument platforms deployed on or from BAS research ships, BAS aircrafts, satellite remote sensing and others.

Scientific Objectives

This project was implemented in order to measure change and variability in the Earth system. Its long term duration allows for the monitoring of processes that could be missed in shorter term studies and experiments. The data collected is also used to check and improve the reliability of models used to stimulate and predict the behavior of the Earth system.

The main objectives are:

• Topographic survey
• Geosciences survey
• Biological survey and monitoring
• Atmospheric and oceanographic monitoring

Data Availability

The data sets obtained through this project are available to the academic community.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for JR19980114_CTD_JR28_CTD043

Please note:the supplied parameters may not have been sampled from all the bottle firings described in the table above. Cross-match the Sample Reference Number above against the SAMPRFNM value in the data file to identify the relevant metadata.

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

No Fixed Station Information held for the Series

BODC Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle: