Metadata Report for BODC Series Reference Number 2094578

• 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

Varian 3300 Gas Chromatograph

The Varian 3300 gas chromatograph separates and analyses gas mixtures in water or air. The instrument includes an injector, autosampler, capillary column and one or more detectors. The sample is vapourised then transported along the column within an inert gas flow.

The column oven accepts packed or fused silica capillary columns, while the instrument accommodates a range of standard and capillary injectors and a variety of detectors. The carrier gas may be air, helium, hydrogen, nitrogen or argon-methane, depending on the type of detector used. Optional carrier gas and oxygen filters may also be incorporated into the instrument. The equipment is controlled by a built-in microcomputer and can perform electron-impact, chemical ionisation, and negative ion analysis. The instrument was originally manufactured by Varian, Inc., which was bought by Agilent Technologies in 2010.

Specifications

FID- Flame Ionization
TSD- Thermionic Sensitive
ECD- Electron capture
FPD- Flame photometric
TCD- Thermal Conductivity
ELCD- Electrolytic Conductivity
PID- Photo-ionization

Further details can be found in the manufacturer's manual.

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.

Particulate Trace Metals for cruises on Belgica, Charles Darwin and RRS Discovery

Document History

Converted from CDROM documentation.

Content of data series

Data Originator

Dr Lei Chou, ULB, Brussels, Belgium.

Sampling strategy and methodology

CruisesBelgica BG9309, BG9322, BG9412 and BG9506, Charles Darwin CD84 and CD94 and RRS Discovery DI216

Samples were obtained using one of two protocols. The protocol used may be identified by the gear code in the EVENT entry for the data (SAP or GPCENT).

SAP collection

Challenger Oceanics in-situ stand-alone pumps (SAPs) were used to sample particulate material. The instruments were deployed on kevlar rope from an auxiliary winch and were switched on and off by a programmable timer to ensure that the pump only sampled when in position at the desired depth. Membrane filters with a 0.4 micron pore size were used to collect the particulate material.

On recovery the filters were rinsed and dried in clean conditions. Back at the home laboratory, the suspended particulate material was ultrasonically detached from the filter for analysis.

GPCENT collection.

Suspended particulate matter was collected by continuous flow centrifugation using an Alpha-Laval oil purifier (model MAB 104) specially coated for oceanographic use. Water supply was adjusted to approximately 1 cubic metre per hour. Samples were collected both when the ship was on station and steaming between stations for about 6-10 hours.

Samples were taken from the centrifuge body using a stainless steel spatula, stored in acid-washed PET vials and immediately deep frozen. After weighing (wet weight) the sample was subdivided for C/N, trace metal and isotope analysis.

The samples were analysed for Al, Cu, Fe, Mn, Cr, Ni, Co, Zn, Cd and Pb by direct injection of solid samples as slurries using electrothermal atomic absorption spectroscopy in a Varian Spectraa-300 spectrometer with Zeeman correction.

The analytical conditions were as follows:

Peak area measurement mode was used for all the above elements.

Major elements were determined by Inductively Coupled Plasma emission spectroscopy after complete digestion of the samples by an HNO₃/HCl/HF mixture in a Teflon bomb in a microwave oven.

If there was insufficient material for the direct injection technique, trace elements were also determined on the digested samples either by ICP, if present in sufficient concentration, or by AA. The parameter codes have been set up to indicate the predominant method for the element.

Comments on data quality

It is reported in the OMEX I final report that ULB participated in the QUASIMEME intercalibration exercise and obtained the following results. The certified values are given in brackets.

The good agreement with the certified values gives confidence in the ULB particulate trace metal data.

Charles Darwin cruise CD94

A number of the filters were reported by the data originator to have anomalously high concentrations for some metals that have been attributed to sample contamination. These have been flagged as 'L' in the database.

RRS Discovery cruise DI216

The CTD cable used on this cruise was in very poor condition and a clearly visible plume of rust could be seen in the water each time the CTD was deployed. Although the SAPs were deployed on kevlar rope, the SAP sampling had to be preceded by a CTD cast to determine the water column structure for assigning the sampling depths.

There is clear evidence in the iron data that most of the SAP samples were polluted by the plume generated by this cast. Consequently, the metal data have been heavily flagged 'L' to reflect the comments of the data originator.

In view of this obvious contamination problem any of the SAP data from this cruise, whatever its associated flag value, should be used with caution.

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 DI216_CTD_CTD21

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: DI216_CTD_CTD21

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.