Metadata Report for BODC Series Reference Number 2101718

• 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.

JC086 discrete dissolved oxygen sampling document

Originator's protocol for data acquisition and analysis

The following information contains extracts from the JC086 cruise report.

Water samples were collected immediately following recovery of the CTD using a silicon tube attached to the Niskin bottle spigot. The silicon tube was lowered into the bottom of a volume calibrated glass bottle and water from the Niskin bottle was allowed to overflow from the bottle until it had been flushed with approximately three times the volume required to fill it.

Discrete dissolved oxygen samples were taken to calibrate the CTD oxygen sensor and Niskin bottles were fired after reviewing the CTD profile.

SAMS Analysis

Samples were fixed immediately using 1ml of 3M MnSO4 and 1ml of 8M NaOH + 4M NaI and the temperature of fixing recorded using a digital thermometer in a separate sample bottle. Samples were fixed by adding 1 ml of manganese chloride followed by 1 ml of alkaline iodide with care being taken not to introduce any air bubbles to the solutions. An hour after collection samples were shaken and subsequent analysis occurred within six hours of this.

1 ml 3 M sulphuric acid was added to the sample, which was then stirred with a small magnetic stirrer on a Radiometer autotitrator until the precipitate was dissolved. Before every analytical session the titrant (0.3 M Na₂S ₂O₃) was standardised using an in-house gravimetrically prepared 0.009M KIO₃ standard. End points were recorded by the auto burette.

Triplicate oxygen samples were collected from up to 3-4 selected depths on 28 CTD casts deployed throughout the JC086 cruise. 278 samples in total were collected and analysed. 19 samples were either lost due to air being trapped within the bottle or being spoilt during analysis.

NOC Analysis

From each depth sampled, a duplicate was taken to allow a comparison of the values. Special care was taken at the time of sampling to not produce bubbles. Immediately after sampling, samples were spiked, first with 1 ml of manganous chloride 3M and secondly with 1 ml of alkaline iodide (sodium hydroxide (8M) and sodium iodide (4M). Samples were shaken straight after spiking and one hour after sampled to allow complete reaction of the chemicals with the dissolved oxygen.

Analysis was performed on board as soon as possible, following the Winkler titration method (Carpenter, 1965) and using a high precision 5ml automatic burette and a Titrino unit supplied by Metrohm.

BODC data processing procedures

The oxygen 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. Data that were considered unrealistic were flagged suspect. Metadata collected from the various data files were favoured by BODC over the metadata recorded in the cruise report logs in the JC086 cruise report.

Content of data series

Data quality report

Flags in the Originators data file were converted to BODC flags.

References cited

Griffiths C. R. et al., (2013). RRS James Cook Cruise JC086, 06 May 2013 - 26 May 2013. Govan to Govan, Scotland - the Extended Ellett Line. Scottish Association for Marine Science. (Scottish Marine Institute, Oban).

Available - Cruise JC086 Internal Report

Project Information

Oceans 2025 Theme 10, Sustained Observation Activity 4: The Extended Ellett Line

The Ellett Line (begun in 1975 and since 1996 the Extended Ellett Line from Scotland to Iceland) crosses important north Atlantic Meridional Overturning Circulation (MOC) components and thus provides an additional contribution to understanding the north Atlantic response to climate change. Sustained Observation Activity (SO) 4 will repeat this section annually collecting a wide variety of physical and biogeochemical measurements, and will, to enhance the time variable component, make use of Argo floats and gliders. SO 4 will be implemented by physical, biological and chemical scientists at the National Oceanography Centre, Southampton (NOCS) and the Scottish Association for Marine Science (SAMS).

SO 4 formally contributes to the Department for Environment, Food and Rural Affairs (DEFRA)-funded Marine Environmental Change Network (MECN). Established in 2002 to coordinate and promote the collection and utilisation of marine time-series and long-term data sets, the goal of the network is to use long-term marine environmental data from around the British Isles and Ireland to separate natural fluctuations from global, regional and local anthropogenic impacts.

The specific deliverables for SO 4 are:

• A time series of the evolution of the hydrography of the northeast Atlantic, together with a more formal understanding of the causes of any changes observed
• An archived data set available to the international community via the British Oceanographic Data Centre (BODC)
• A platform for further scientific research

More detailed information on this Work Package is available at pages 15 - 16 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10

Weblink: http://www.oceans2025.org/

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for JC086_CTD_C008

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.

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: JC086_CTD_C008

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

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.