Metadata Report for BODC Series Reference Number 1875230

• 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

Open Data supplied by Natural Environment Research Council (NERC)

You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."

Narrative Documents

TitraLab TIM90, ABU91/ABU93 Automated Titration System

A modular, automated titration system for the laboratory. This includes a TIM90 titration manager, which can manage up to 3 burettes and store 40 methods; and either an ABU 91 Autoburette (one burette), or an ABU 93 Triburette (three burettes), both with 1 ml, 5 ml, 10 ml and 25 ml selectable quantities.

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.

DY052 discrete CTD salinity, inorganic nutrients and dissolved oxygen samples

Originator's Protocol for Data Acquisition and Analysis

The following information contains extracts from the DY052 cruise report.

Discrete samples were taken from the majority of the 89 CTD casts made during the DY052 Extended Ellet Line cruise. The samples were taken to measure salinity, dissolved oxygen and nutrient concentrations and were analysed as follows:

Salinity

Salinity samples were drawn from each unique depth. When two bottles were fired at the same depth only one bottle was sampled. Bottle samples were collected after oxygen and carbon into glass bottles with plastic inserts and caps. Some bottles on the Scottish Shelf east of Barra were not sampled due to the strong salinity signals on the shelf and to reduce Autosal operator workload when arriving in port. For each sample, the bottle and cap was rinsed three times and then filled with sample. The neck, threads, and cap were carefully dried, to prevent salt crystals from forming around the opening, and the insert and cap were put on the bottle for storage. Filled salt bottles were placed in the Autosal lab and allowed a minimum of 24 hours to reach the ambient lab temperature before analysis on the Autosal.

Oxygen

Dissolved oxygen concentrations were measured using the seawater samples. Sampling and analysis were performed 24hrs a day from every CTD cast using Winkler photometric auto-titration. Methodologies followed those documented in GO-SHIP protocols (Langdon,2010) and based on the standard methodologies of Carpenter 1965 adapted for large scale hydrographic studies (e.g. Culberson, 1991 and Dickson, 1995).

Nutrients

Nutrient samples were collected in 50ml acid pre-cleaned polythene vials directly from the CTD spigots without the use of a tube and using a single half-full rinse prior to collection. Samples were always analyzed within 24 hours of collection and stored in low light conditions at room temperature prior to analysis if analysis time exceeded eight hours after collection time. Measurement was conducted using a Lachat QuikChem 8500 flow injection autoanalyser (Hach Lange). After analysis, the 50ml tubes were double rinsed and reused for subsequent CTD sample collection.

BODC Data Processing Procedures

The sample data were supplied to BODC in an MSTAR format. This file format was converted to ASCII and data were loaded into BODC's ocean database under the ORACLE Relational Database Management System without modification. There were no replicates and no flags were added to the data.

Data Quality Report

There are a few instances where data exists in the Mstar file where no bottle was fired and so has no corresponding depth. This occurred three times for nutrients and once for oxygen. Without being able to confirm the cast and bottle these samples came from BODC have not been able to load the data to the BODC database. Below are these instances -

• Cast 19, bottle 23 (Silc -0.18, Phos 0.26, Totnit 4.7 (µmol/l))
• Cast 24, bottle 17 (Silc 0.95, Phos 0.2, Totnit 2.23 (µmol/l))
• Cast 63, bottle 12 (Silc 0.56, Phos 0.04, Totnit 0.05 (µmol/l))
• Cast 28, bottle 2 (Botoxy 239.21µmol/kg)

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

No Document Information Held for the Series

Related Data Activity activities are detailed in Appendix 1

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:

Appendix 1: DY052_CTD_CTD089

Related series for this Data Activity are presented in the table below. Further information can be found by following the appropriate links.

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