Metadata Report for BODC Series Reference Number 1868325

• 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

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 cruise Belgica BG9309

Document History

Converted from CDROM documentation.

Content of data series

Data Originator

Dr Jean-Marie Martin, Institut de Biogeochimie, France.

Sampling strategy and methodology

Water samples were collected using either 10 l acid-cleaned polypropylene bottles deployed manually or Teflon lined GoFlo bottles deployed on a CTD rosette. The samples were filtered under nitrogen pressure through acid-cleaned 0.4 micron Nuclepore filters. 1-2 litres were passed through the filter and discarded to guard against adsorption and/or release of organic carbon from the filter.

A 50ml sample was poisoned with HgCl₂ for DOC analysis. Filtered water was then passed through a cross-flow ultra-filtration (CFF) system with a polysulphate membrane (10⁴Daltons) to separate colloids from the truly dissolved fraction. Quadruplate samples were collected when the concentration factor was around 4-6. All filtration was conducted using ultra-clean techniques under laminar-flow clean benches.

DOC was determined on the filtrate and ultra-filtrate by high temperature catalytic oxidation using a Shimadzu TOC-5000 analyser. Samples were injected into a furnace at 680 °C onto a catalyst made of 1.2% Pt coated SiO₂. The CO₂ produced was measured by a non-dispersive infra-red (NDIR) detector. The instrument and water blanks were evaluated for each set of sample analysis as described by Cauwet (1994).

Comments on data quality

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_GC11E

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_GC11E

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