Metadata Report for BODC Series Reference Number 2134299

• 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

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.

If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:

"Contains public sector information licensed under the Open Government Licence v1.0."

Narrative Documents

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.

RRS Discovery Cruise D321 (D321A) Discrete Oxygen CTD Samples

Cruise details

Content of data series

Originator's Data Acquisition and Processing

Sampling Strategy

Discrete dissolved oxygen bottle samples were taken from 52 CTD casts during the D321(A) cruise to the Icelandic Basin and Extended Ellett Line. Of these, 22 casts formed part of CTD survey 1, 8 of CTD survey 2, 14 of SeaSoar survey S1, 3 of SeaSoar survey S2 and 6 formed part of the Extended Ellett Line (EEL). Samples were primarily utilised for the calibration of CTD oxygen senors. For further information on sampling strategy please see p198-199 of the cruise report .

Instrument description and methodology

Water was collected from depth using a Seabird 911+ stainless steel CTD unit fitted with a Seabird carousel (type SBE 32) and 24 x 20 litre OTE water bottles. Samples were analysed following the procedure outlined in Holley and Hydes (1). Dissolved oxygen concentration was determined using the Winkler Titration method on a SIS (Sensoren Instrumente Systeme GmbH) Dissolved Oxygen Analyser with colourimetric end-point detection. Further information on methodology can be found in the cruise report , p198-200.

Data processing

Samples were corrected for blank samples and the normality of the sodium thiosulphate titrant (determined using potassium iodate standards). A more detailed account of originator's data processing can be found in the cruise report from p198-200.

Field calibrations

None

BODC Data Processing

Data processing

Data arrived at BODC in a Microsoft Excel spreadsheet which contained all oxygen samples taken during the cruise. The spreadsheet was initially converted into a Comma Separated Values format file (.csv) and appropriate BODC parameter codes were assigned. The following table shows how the variables supplied were mapped to BODC parameter codes. Subsequently, duplicate samples taken from one water bottle were averaged so that the file contained only one measurement per water bottle sampled. Where duplicates contained a measurement considered suspect by the originator, only the non-suspect data were kept in the final file. Data were also flagged suspect where the accuracy of averaged duplicate samples was greater than 1% (2). The reformatted data were then visually inspected by plotting depth profiles in Microsoft Excel. Suspect data were marked by adding an appropriate quality control flag (see table below). For example,

Data banking

The .csv file was loaded into an database table where measurements were linked to corresponding depths through the CTD rosette bottle no. (supplied by the originator) and the CTD rosette bottle no. obtained from electronic Seabird CTD logs (which contained a reading of accurate depth for each bottle fired). This was achieved via BODC unique bottle identifiers (IBTTLE) which were already associated with each CTD bottle fired during the cruise. Only one discrepancy was noted during the process. On cast 16208A, the originator supplied data from rosette bottle no. 15 but only bottle nos. 1-13 existed in the CTD electronic logs. However, following further correspondence with the originator, this was found to be a mistake and the sample was actually obtained from bottle 13 (6.8 m depth). Data were then loaded into the main BODC relational database managment system.

Data Quality

When the data arrived at BODC, the originator had flagged several measurements as suspect. These were considered suspect because a small bubble in the bottle may have effected accuracy during analysis or the end point of the titration was not calculated correctly so the software estimated the end point. These were subsequently flagged 'L' during BODC processing.

Problem report

None

References

(1) Holley, S.E. and Hydes, D.J. (1995) Procedures for the determination of dissolved oxygen in seawater, James Rennell Centre for Ocean Circulation, Internal Document No. 20, 35pp.

(2) Holley, S.E. and Hydes, D.J. (2007) Procedures for the determination of dissolved oxygen in seawater - revised. In:Evaluation of the Anderaa Oxygen Optode in Continuous use in the NOC Portsmouth Bilbao Ferrybox System 2005, 2006, with an assessment of the likely errors in the estimation of oxygen concentration anomalies. NOCS internal document No. 7, 38pp.

Project Information

Oceans 2025 - The NERC Marine Centres' Strategic Research Programme 2007-2012

Who funds the programme?

The Natural Environment Research Council (NERC) funds the Oceans 2025 programme, which was originally planned in the context of NERC's 2002-2007 strategy and later realigned to NERC's subsequent strategy (Next Generation Science for Planet Earth; NERC 2007).

Who is involved in the programme?

The Oceans 2025 programme was designed by and is to be implemented through seven leading UK marine centres. The marine centres work together in coordination and are also supported by cooperation and input from government bodies, universities and other partners. The seven marine centres are:

• National Oceanography Centre, Southampton (NOCS)
• Plymouth Marine Laboratory (PML)
• Marine Biological Association (MBA)
• Sir Alister Hardy Foundation for Marine Science (SAHFOS)
• Proudman Oceanographic Laboratory (POL)
• Scottish Association for Marine Science (SAMS)
• Sea Mammal Research Unit (SMRU)

Oceans2025 provides funding to three national marine facilities, which provide services to the wider UK marine community, in addition to the Oceans 2025 community. These facilities are:

• British Oceanographic Data Centre (BODC), hosted at POL
• Permanent Service for Mean Sea Level (PSMSL), hosted at POL
• Culture Collection of Algae and Protozoa (CCAP), hosted at SAMS

The NERC-run Strategic Ocean Funding Initiative (SOFI) provides additional support to the programme by funding additional research projects and studentships that closely complement the Oceans 2025 programme, primarily through universities.

What is the programme about?

Oceans 2025 sets out to address some key challenges that face the UK as a result of a changing marine environment. The research funded through the programme sets out to increase understanding of the size, nature and impacts of these changes, with the aim to:

• improve knowledge of how the seas behave, not just now but in the future;
• help assess what that might mean for the Earth system and for society;
• assist in developing sustainable solutions for the management of marine resources for future generations;
• enhance the research capabilities and facilities available for UK marine science.

In order to address these aims there are nine science themes supported by the Oceans 2025 programme:

• Climate, circulation and sea level (Theme 1)
• Marine biogeochemical cycles (Theme 2)
• Shelf and coastal processes (Theme 3)
• Biodiversity and ecosystem functioning (Theme 4)
• Continental margins and deep ocean (Theme 5)
• Sustainable marine resources (Theme 6)
• Technology development (Theme 8)
• Next generation ocean prediction (Theme 9)
• Integration of sustained observations in the marine environment (Theme 10)

In the original programme proposal there was a theme on health and human impacts (Theme 7). The elements of this Theme have subsequently been included in Themes 3 and 9.

When is the programme active?

The programme started in April 2007 with funding for 5 years.

Brief summary of the programme fieldwork/data

Programme fieldwork and data collection are to be achieved through:

• physical, biological and chemical parameters sampling throughout the North and South Atlantic during collaborative research cruises aboard NERC's research vessels RRS Discovery, RRS James Cook and RRS James Clark Ross;
• the Continuous Plankton Recorder being deployed by SAHFOS in the North Atlantic and North Pacific on 'ships of opportunity';
• physical parameters measured and relayed in near real-time by fixed moorings and ARGO floats;
• coastal and shelf sea observatory data (Liverpool Bay Coastal Observatory (LBCO) and Western Channel Observatory (WCO)) using the RV Prince Madog and RV Quest.

The data is to be fed into models for validation and future projections. Greater detail can be found in the Theme documents.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for D321A_CTD_16287A

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

Fixed Station Information

Extended Ellett Line

The Extended Ellett Line is a hydrographic transect consisting of 64 individual fixed stations which have been occupied, typically on an annual basis, since September 1996. The Line runs from the south of Iceland, across the Iceland Basin to the outcrop of Rockall, and across the Rockall Trough to the north west coast of Scotland (see map). CTD dips and associated water sampling for the analysis of nutrients are routinely performed during each station occupation.

The Extended Ellett Line augments the original Ellett Line time series - a shorter repeated transect which encompassed those stations between Rockall and Scotland. Work on the Ellett Line was typically carried out at least once a year between 1975 and 1996.

Map of standard stations (1996-present)

Map produced using the GEBCO Digital Atlas

The white triangles indicate the nominal positions of the Extended Ellett Line stations visited since September 1996. Measurements made along the Extended Ellett Line lie within a box bounded by co-ordinates 56° N, 21° W at the south west corner and 65° N, 6° W at the north east corner.

Nominal Extended Ellett Line stations (September 1996-present)

Listed below are nominal details of the standard hydrographic stations that form the Extended Ellett Line. The majority of these stations have been sampled since the outset, although several have been added more recently.

Occupations of the Extended Ellett Line (September 1996-present)

* These cruises only surveyed the original hydrographic section between Scotland and Rockall.

Related Fixed Station activities are detailed in Appendix 2

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: D321A_CTD_16287A

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.

Appendix 2: Extended Ellett Line

Related series for this Fixed Station 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.