Metadata Report for BODC Series Reference Number 1868405

• 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

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.

GO-FLO Bottle

A water sampling bottle featuring close-open-close operation. The bottle opens automatically at approximately 10 metres and flushes until closed. Sampling with these bottles avoids contamination at the surface, internal spring contamination, loss of sample on deck and exchange of water from different depths.

There are several sizes available, from 1.7 to 100 litres and are made of PVC with a depth rating of up to 500 m. These bottles can be attached to a rosette or placed on a cable at selected positions.

Dissolved and Colloidal Organic Carbon for cruises Belgica BG9309 and BG9322

Document History

Converted from CDROM documentation.

Content of data series

Data Originator

Dr Chou Lei, ULB, Brussels, Belgium.

Sampling strategy and methodology

Water samples were collected using either 10 l acid-cleaned polypropylene bottles deployed manually or Niskin/GoFlo bottles deployed on a CTD rosette.

Water bottle samples were filtered using pre-ashed (450 °C) GF/F filters. 10 ml samples were transferred into 15 ml glass ampoules which were poisoned with 100 µl of 1 g/l HgCl₂ and sealed.

Back at the laboratory the samples were assayed using a Shimadzu TOC-5000 analyser.

Comments on data quality

Belgica BG9309

The ULB data set contains a number of high values of up to nearly 6000 µM. Of particular concern are the data from the upper 300m from station 11 which jump from 138 µM at 400m to 2403 µM at 300m and some of the data from the Zodiac transects. The IBM data from station 11 (but a different cast) give values of 1-200 µM in the upper 200m and their values for most samples from the rias are significantly lower than the ULB data.

The ULB values from the upper 300m of station 11 have been flagged suspect, together with samples from the rias in excess of 400 µM. The possibility of contamination of some samples has been suggested by the data originator as the cause of the problem. Values in the range 200-400 µM have been left unflagged but users should bear in mind that they may also be contaminated to some extent.

References

Cauwet, G. 1994. HTCO method for dissolved organic carbon analysis in seawater: influence of catalyst on blank estimation, Marine Chemistry, 47, 55 64.

Miller, A.E.J, Mantoura, R.F.C., Preston, M.R. and Suzuki, Y, 1993. Preliminary study of DOC in the Tamar Estuary, UK, using UV-persulphate and HTCO techniques. Mar. Chem., 41, 223-228.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for BG9309_CTD_GC16

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: BG9309_CTD_GC16

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