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Metadata Report for BODC Series Reference Number 1868595

Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
Non-toxic sea water supply  continuous water samplers
Instrument Mounting research vessel
Originating Country Germany
Originator Dr Robin Keir
Originating Organization Research Center for Marine Geosciences, Kiel (now GEOMAR Helmholtz Centre for Ocean Research, Kiel (East Shore Campus))
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) OMEX I

Data Identifiers

Originator's Identifier PS211_GPUMP_CH4X_73:
BODC Series Reference 1868595

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1995-08-31 13:56
End Time (yyyy-mm-dd hh:mm) 1995-09-11 04:00
Nominal Cycle Interval -

Spatial Co-ordinates

Southernmost Latitude 38.69976 N ( 38° 42.0' N )
Northernmost Latitude 64.47028 N ( 64° 28.2' N )
Westernmost Longitude 31.52919 W ( 31° 31.8' W )
Easternmost Longitude 9.59538 W ( 9° 35.7' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth 4.0 m
Maximum Sensor or Sampling Depth 4.0 m
Minimum Sensor or Sampling Height -
Maximum Sensor or Sampling Height -
Sea Floor Depth -
Sea Floor Depth Source -
Sensor or Sampling Distribution Unspecified -
Sensor or Sampling Depth Datum Unspecified -
Sea Floor Depth Datum Unspecified -


BODC CODERankUnitsTitle
AADYAA011DaysDate (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ011DaysTime (time between 00:00 UT and timestamp)
ALATGP011DegreesLatitude north relative to WGS84 by unspecified GPS system
ALONGP011DegreesLongitude east relative to WGS84 by unspecified GPS system
CH4CGCXX1Nanomoles per litreConcentration of methane {CH4 CAS 74-82-8} per unit volume of the water body [dissolved plus reactive particulate phase] by gas chromatography

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

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

Non-toxic (underway) sea water supply

A source of uncontaminated near-surface (commonly 3 to 7 m) seawater pumped continuously to shipboard laboratories on research vessels. There is typically a temperature sensor near the intake (known as the hull temperature) to provide measurements that are as close as possible to the ambient water temperature. The flow from the supply is typically directed through continuously logged sensors such as a thermosalinograph and a fluorometer. Water samples are often collected from the non-toxic supply. The system is also referred to as the underway supply.

Methane for cruises Meteor M27_1, Belgica BG9506 and Poseidon PS211

Document History

Converted from CDROM documentation.

Content of data series

CH4AGCXX Atmospheric methane
Gas chromatography
Nanomoles per litre
CH4CGCXX Dissolved methane
Gas chromatography
Nanomoles per litre

Data Originator

Professor Robin Keir, GEOMAR, Kiel, Germany.

Sampling strategy and methodology

Water samples were collected from the CTD rosette and analysed on board ship for dissolved methane. The gas phase was obtained by two methods. The first involved a partial separation of gas and water phases under vacuum using repeated application of ultrasound. The second utilised equilibration of the water sample with a small volume of added pure nitrogen head space. Dissolved methane was then computed from the measured gas phase mixing ratio and the methane solubility at the laboratory conditions of temperature and salinity.

Measurements of surface dissolved methane were obtained as a by-product of the underway pCO2 determination. Surface sea water (from an inlet in the bow of Belgica or the 'moon pool' of Poseidon) was continuously pumped through the gas equilibrator where the dissolved gases exchanged with a closed loop of air. The gas loop was sampled periodically (approximately every 10 minutes) and the CO2 separated from the methane by the GC column. The CO2 was then reduced by hydrogen over a nickel catalyst and analysed as methane. This resulted in two peaks that could be quantified separately for methane and carbon dioxide.

Air samples were collected periodically (approximately hourly) from an inlet mounted on the bow of the ship and analysed in the same way as the equilibrated gases.

The surface methane data were reduced by the data originator to average values for each one degree square traversed by the ship. The data in this reduced form could be loaded into the database for Poseidon PS211 because the cruise track was a simple straight line. However, Belgica passed through a number of squares several times during the cruise making loading of the spatially averaged data impossible. Consequently, the full raw data set (water samples every 10 minutes with an air sample approximately every hour) has been loaded for this cruise.

Project Information

Ocean Margin EXchange (OMEX) I


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


Cruise Name PO211
Departure Date 1995-08-31
Arrival Date 1995-09-11
Principal Scientist(s)Ludger Mintrop (Institute of Marine Sciences, Kiel)
Ship FS Poseidon

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:

Flag Description
Blank Unqualified
< Below detection limit
> In excess of quoted value
A Taxonomic flag for affinis (aff.)
B Beginning of CTD Down/Up Cast
C Taxonomic flag for confer (cf.)
D Thermometric depth
E End of CTD Down/Up Cast
G Non-taxonomic biological characteristic uncertainty
H Extrapolated value
I Taxonomic flag for single species (sp.)
K Improbable value - unknown quality control source
L Improbable value - originator's quality control
M Improbable value - BODC quality control
N Null value
O Improbable value - user quality control
P Trace/calm
Q Indeterminate
R Replacement value
S Estimated value
T Interpolated value
U Uncalibrated
W Control value
X Excessive difference

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
0 no quality control
1 good value
2 probably good value
3 probably bad value
4 bad value
5 changed value
6 value below detection
7 value in excess
8 interpolated value
9 missing value
A value phenomenon uncertain
B nominal value
Q value below limit of quantification