Metadata Report for BODC Series Reference Number 1655183

• 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

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.

Phytoplankton pigment concentration data series for cruise RRS Charles Darwin CD132

Content of Data Series

Originator's Protocol for Data Acquisition and Analysis

The following methodology was compiled from information extracted from the CD132 cruise report (Burkill 2002).

Samples were obtained onboard by vacuum filtering of CTD-collected seawater through 25mm GF/F filters. Pigments were extracted from the filters using 90% acetone with apo-carotenal as an internal standard. Pigment extracts were analysed by reverse-phase HPLC using a Shandon Hypersil MOS-2 C8 column (100 x 4.6mm, 3micron), Thermoseparations UV6000 photodiode array detector (300-700nm) and a binary mobile phase (70:30% methanol:1M ammonium acetate and 100% methanol). Pigment identities were secured through co-elution with authentic pigment standards (VKI, Denmark and Sigma Chemical Co). Not all samples were analysed onboard as the HPLC broke down around 200 miles off Oman (station 8). From station 8 onwards, the filters were preserved in liquid nitrogen and analysed back at the laboratory.

References

Burkill PH (2002). RRS Charles Darwin cruise 132. Analysing the Microbial Biodiversity of the Indian Ocean - AMBITION. 30 Aug-29 Sep 2001. Marine and Freshwater Microbial Biodiversity Cruise Report No.1, 56pp.

BODC Data Processing Procedures

Data were submitted to BODC in an Excel spreadsheet. Sample metadata were checked against information held in the database. Discrepancies were crosschecked with the data originator prior to correction. Parameter codes defined in BODC's parameter dictionary were assigned to the variables. In order to standardise parameter units with that held in BODC's parameter dictionary, chlorophyll a concentration was converted from ng l-1 to µg l-1 by dividing the original value by 1000. The data were then loaded into the BODC Research Project Database under the Oracle Relational Database Management System without further modification.

Data Quality Report

Although the quality of the data is not affected by what follows, users should be aware that:

1) the 50m bottle from cast CD132_001 was reported as leaking by the CTD operator and has therefore been flagged 'L' in the database. However, associated data do not appear to have been affected.

2) For cast CD132_034, the unintentional firing of an extra bottle at 153m was not reported in the CTD log sheet resulting in a mismatch in the attribution of bottle depth to samples collected above 200m. Samples have been re-attributed to their correct depth at BODC prior to loading in the database. The bottle entries that were affected by this problem have been associated with an 'O' flag.

3) Bottle leakage also reported for bottles fired during cast CD132_016 at 298.3m and during cast CD132_028 at 11.9m.

Problem Report

None Reported

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for CD132_CTD_CD132_019

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: CD132_CTD_CD132_019

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.