Metadata Report for BODC Series Reference Number 2297370

• 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.

Dissolved and Colloidal Trace Metals for cruises Belgica BG9309 and Charles Darwin CD84 and CD94

Document History

Converted from CDROM documentation.

Content of data series

Data Originator

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

Sampling strategy and methodology

Samples were collected using either manually filled 10 litre acid-washed polypropylene bottles from an inflatable boat in the rias or Teflon coated GoFlo bottles deployed on a CTD rosette. On Charles Darwin cruise CD94, lever action Niskin bottles with external springs were used instead of GoFlo bottles.

The samples were filtered through acid-cleaned 0.4 micron Nuclepore filters under nitrogen pressure under laminar-flow clean benches using clean working practices. For colloidal metal determinations, an aliquot of filtrate was further filtered through a cross-flow ultra-filtration (CFF) system with a polysulphate membrane (10⁴ Daltons) to separate colloids.

Hydrophobic metal-organic complexes were extracted on board from both filtered and ultra-filtered samples through pre-conditioned C₁₈ Sep-Pak cartridge (Millipore) via a peristaltic pump and then eluted by a 50% methanol solution using a method modified from Mills et al. (1987).

The metal contents were measured by GFAAS (Perkin Elmer 3030) after extraction in a Class 100 clean room using a method modified from Danielsson et al. (1982). The extraction was carried out at pH 4-5 for CD, Fe, Cu and Ni with 1% of APDC/DDDC as complexant. For Mn the extraction (adapted from Statham, 1985) was run at a pH range of 9-9.5 using 2% APDC/DDDC as complexant. Detection levels have been determined as:

Cd 0.003 nM
Cu 0.05 nM
Ni 0.06 nM
Fe 0.09 nM
Mn 0.06 nM

Extraction efficiency was checked with standard seawater reference material (NASS-4, Canada). 88-120% recoveries were obtained (140% for Fe). The reagent blanks were close to the detection limits and represent less than 5% of the lowest sample concentration.

Colloidal concentrations were determined as the difference between filtered and ultra-filtered dissolved metal determinations.

Comments on data quality

Charles Darwin cruise CD84

In the second OMEX annual report, IBM reported that an intercalibration exercise between IBM and SOC on this cruise showed the IBM Cd concentrations to be about 20% higher, Cu determinations from both laboratories to be virtually identical and IBM Ni determinations to be lower.

A small number of very high values in both the IBM and SOC data sets that may only be explained in terms of contamination have been flagged suspect ('M') by BODC. Other values flagged 'M' which otherwise look reasonable are from bottles for which there is strong evidence of contamination of deep water samples by shallow water through leakage.

A number of data values in the ULB aluminium data set have been flagged either 'L' or 'M' in the database. The data values flagged 'L' were reported as contaminated by the originator. The values flagged 'M' are from bottles where there is strong evidence of contamination of deep water samples by shallow water through leakage.

Charles Darwin cruise CD94

IBM data values identified as contaminated by the data originator (through notes on the spreadsheet supplied) have been flagged 'L' in the database.

References

Achterberg, E. P. and van den Berg, C. M. G., 1994. Automated voltammetric system for shipboard determination of metal speciation in sea water. Anal. Chim. Acta 284, 463-471.

Colombo, C and van den Berg, C. M. G., 1997. Simultaneous determination of several trace metals in seawater using cathodic stripping voltammetry with mixed ligands. Anal. Chim. Acta 337, 29-40.

Danielsson, L.G., Magnusson, B., Westerlund, S. and Zhang, K., 1982. Trace metal determination in estuarine waters by electrothermal AAS after extraction of dithiocarbamate complexes into freon. Anal. Chim. Acta, 144, 183-188.

Hydes, D.J. and P.S. Liss, 1976. A fluorometric method for the determination of low concentrations of dissolved aluminium in natural waters. The Analyst, 101, 922-931.

Mills, G.L., McFadden, E. and Quinn, J.G., 1987. Chromatographic studies of dissolved organic matter and copper-organic complexes isolated from estuarine waters. Mar. Chem., 20, 313-323.

Morley, N.H., Fay, C.W., and Statham, P.J., 1988. Design and use of a clean shipboard handling system for seawater samples. Advances in Underwater Technology, Ocean Science and Offshore Engineering, 16, Oceanology '88, 283-289.

Nimmo, M., van den Berg, C. M. G. and Brown, J., 1989. The chemical speciation of dissolved nickel, copper, vanadium and iron in Liverpool Bay, Irish Sea. Coastal Shelf Res. 29, 57-74.

Pihlar, B., Valenta, P. and Nurnberg, H. W., 1981. New high-performance analytical procedure for the voltammetric determination of nickel in routine analysis of waters, biological materials and food. Fres. Z. Anal. Chem. 307, 337-346.

Statham, P.J., 1985. The determination of dissolved manganese and cadmium in sea water at low nmol l-1 concentrations by chelation and extraction followed by electrothermal atomic absorption spectrometry. Anal. Chim. Acta, 169, 149-159.

Tappin, A.D., 1988 Trace metals in shelf seas of the British Isles, Ph.D.Thesis, University of Southampton, 279pp.

Tappin A.D., D.J. Hydes, P.J. Statham and Burton, J.D., 1992. Concentrations, distributions and seasonal variability of dissolved Cd, Co, Cu, Mn, Ni, Pb and Zn in the English Channel. Continental Shelf Research, 12,.

Project Information

Ocean Margin EXchange (OMEX) I

Introduction

OMEX was a European multidisciplinary oceanographic research project that studied and quantified the exchange processes of carbon and associated elements between the continental shelf of western Europe and the open Atlantic Ocean. The project ran in two phases known as OMEX I (1993-1996) and OMEX II - II (1997-2000), with a bridging phase OMEX II - I (1996-1997). The project was supported by the European Union under the second and third phases of its MArine Science and Technology Programme (MAST) through contracts MAS2-CT93-0069 and MAS3-CT97-0076. It was led by Professor Roland Wollast from Université Libre de Bruxelles, Belgium and involved more than 100 scientists from 10 European countries.

Scientific Objectives

The aim of the Ocean Margin EXchange (OMEX) project was to gain a better understanding of the physical, chemical and biological processes occurring at the ocean margins in order to quantify fluxes of energy and matter (carbon, nutrients and other trace elements) across this boundary. The research culminated in the development of quantitative budgets for the areas studied using an approach based on both field measurements and modeling.

OMEX I (1993-1996)

The first phase of OMEX was divided into sub-projects by discipline:

• Physics
• Biogeochemical Cycles
• Biological Processes
• Benthic Processes
• Carbon Cycling and Biogases

This emphasises the multidisciplinary nature of the research.

The project fieldwork focussed on the region of the European Margin adjacent to the Goban Spur (off the coast of Brittany) and the shelf break off Tromsø, Norway. However, there was also data collected off the Iberian Margin and to the west of Ireland. In all a total of 57 research cruises (excluding 295 Continuous Plankton Recorder tows) were involved in the collection of OMEX I data.

Data Availability

Field data collected during OMEX I have been published by BODC as a CD-ROM product, entitled:

• OMEX I Project Data Set (two discs)

Further descriptions of this product and order forms may be found on the BODC web site.

The data are also held in BODC's databases and subsets may be obtained by request from BODC.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for CD94_CTD_CTD14

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: CD94_CTD_CTD14

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