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Metadata Report for BODC Series Reference Number 1875254

Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
Niskin bottle  discrete water samplers
General Oceanics GO-FLO water sampler  discrete water samplers
Instrument Mounting lowered unmanned submersible
Originating Country United States
Originator Prof Mary Scranton
Originating Organization Stony Brook University School of Marine and Atmospheric Sciences
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) North Sea Project 1987-1992

Data Identifiers

Originator's Identifier CH50_CTD_CH4X_25:1707
BODC Series Reference 1875254

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1989-04-14 10:50
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -

Spatial Co-ordinates

Latitude 54.33997 N ( 54° 20.4' N )
Longitude 0.75556 E ( 0° 45.3' E )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth 8.4 m
Maximum Sensor or Sampling Depth 51.2 m
Minimum Sensor or Sampling Height 7.8 m
Maximum Sensor or Sampling Height 50.6 m
Sea Floor Depth 59.0 m
Sea Floor Depth Source PEVENT
Sensor or Sampling Distribution Unspecified -
Sensor or Sampling Depth Datum Unspecified -
Sea Floor Depth Datum Unspecified -


BODC CODERankUnitsTitle
ADEPZZ011MetresDepth (spatial coordinate) relative to water surface in the water body
BOTTFLAG1Not applicableSampling process quality flag (BODC C22)
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
CH4SGCXX1PercentSaturation of methane {CH4 CAS 74-82-8} in the water body [dissolved plus reactive particulate phase] by computation from concentration
SAMPRFNM1DimensionlessSample reference number

Definition of BOTTFLAG

0The sampling event occurred without any incident being reported to BODC.
1The filter in an in-situ sampling pump physically ruptured during sample resulting in an unquantifiable loss of sampled material.
2Analytical evidence (e.g. surface water salinity measured on a sample collected at depth) indicates that the water sample has been contaminated by water from depths other than the depths of sampling.
3The feedback indicator on the deck unit reported that the bottle closure command had failed. General Oceanics deck units used on NERC vessels in the 80s and 90s were renowned for reporting misfires when the bottle had been closed. This flag is also suitable for when a trigger command is mistakenly sent to a bottle that has previously been fired.
4During the sampling deployment the bottle was fired in an order other than incrementing rosette position. Indicative of the potential for errors in the assignment of bottle firing depth, especially with General Oceanics rosettes.
5Water was reported to be escaping from the bottle as the rosette was being recovered.
6The bottle seals were observed to be incorrectly seated and the bottle was only part full of water on recovery.
7Either the bottle was found to contain no sample on recovery or there was no bottle fitted to the rosette position fired (but SBE35 record may exist).
8There is reason to doubt the accuracy of the sampling depth associated with the sample.
9The bottle air vent had not been closed prior to deployment giving rise to a risk of sample contamination through leakage.

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

Open Data supplied by Natural Environment Research Council (NERC)

You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."

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.


Bottles may be deployed singly clamped to a wire or in groups of up to 48 on a rosette. Standard bottles have a capacity between 1.7 and 30 L, while Lever Action bottles have a capacity between 1.7 and 12 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.

Methane as part of the North Sea Project

Document History

Converted from CDROM documentation.

Sampling strategy and methodology

During cruises Challenger 48 and 50, a group under Mary Scranton from the Marine Sciences Research Center at the State University of New York at Stony Brook, Stony Brook, NY 11794-5000 USA made measurements of methane concentrations in air and sea water.

Measurements were made on samples from both the CTD rosette sampler and from pump samples. On Challenger 48 a pumped system installed to obtain samples for the tracer distribution study was used. On Challenger 50 the samples were from the ship's general non-toxic sea water supply.

Air samples were taken as discrete samples using a syringe from the windward side of the ship. These data were interpolated to give atmospheric concentrations coincident with water sampling.

The method used for methane analysis was flame ionization gas chromatography following gas extraction using a vacuum extraction method. Basically the sample was permitted to flow into an evacuated sample bulb where dissolved gases were degassed from the water. An aliquot of the headspace in the bulb was then analysed by gas chromatography using a Carle AGC 211 gas chromatograph equipped with a Poropak R column. Calibrations were made relative to standard gases injected between samples.

The methane saturation was computed from the equilibrium value (derived from the atmospheric concentration and the methane solubility coefficient) using the equation:

Saturation (%) = ((CH4-CH4eq)/CH4eq) * 100

The data were supplied to BODC in units of nl/l (dissolved) and ppm (atmospheric). These were converted to molar quantities (nM) by multiplication by 0.04466 and 44.66 respectively.

Project Information

North Sea Project

The North Sea Project (NSP) was the first Marine Sciences Community Research project of the Natural Environment Research Council (NERC). It evolved from a NERC review of shelf sea research, which identified the need for a concerted multidisciplinary study of circulation, transport and production.

The ultimate aim of the NERC North Sea Project was the development of a suite of prognostic water quality models to aid management of the North Sea. To progress towards water quality models, three intermediate objectives were pursued in parallel:

  • Production of a 3-D transport model for any conservative passive constituent, incorporating improved representations of the necessary physics - hydrodynamics and dispersion;
  • Identifying and quantifying non-conservative processes - sources and sinks determining the cycling and fate of individual constituents;
  • Defining a complete seasonal cycle as a database for all the observational studies needed to formulate, drive and test models.

Proudman Oceanographic Laboratory hosted the project, which involved over 200 scientists and support staff from NERC and other Government funded laboratories, as well as seven universities and polytechnics.

The project ran from 1987 to 1992, with marine field data collection between April 1988 and October 1989. One shakedown (CH28) and fifteen survey cruises (Table 1), each lasting 12 days and following the same track, were repeated monthly. The track selected covered the summer-stratified waters of the north and the homogeneous waters in the Southern Bight in about equal lengths together with their separating frontal band from Flamborough head to Dogger Bank, the Friesian Islands and the German Bight. Mooring stations were maintained at six sites for the duration of the project.

Table 1: Details of NSP Survey Cruises on RRS Challenger
Cruise No. Date
CH28 29/04/88 - 15/05/88
CH33 04/08/88 - 16/08/88
CH35 03/09/88 - 15/09/88
CH37 02/10/88 - 14/10/88
CH39 01/11/88 - 13/11/88
CH41 01/12/88 - 13/12/88
CH43 30/12/88 - 12/01/89
CH45 28/01/89 - 10/02/89
CH47 27/02/89 - 12/03/89
CH49 29/03/89 - 10/04/89
CH51 27/04/89 - 09/05/89
CH53 26/05/89 - 07/06/89
CH55 24/06/89 - 07/07/89
CH57 24/07/89 - 06/08/89
CH59 23/08/89 - 04/09/89
CH61 21/09/89 - 03/10/89

Alternating with the survey cruises were process study cruises (Table 2), which investigated some particular aspect of the science of the North Sea. These included fronts (nearshore, circulation and mixing), sandwaves and sandbanks, plumes (Humber, Wash, Thames and Rhine), resuspension, air-sea exchange, primary productivity and blooms/chemistry.

Table 2: Details of NSP Process cruises on RRS Challenger
Cruise No. Date Process
CH34 18/08/88 - 01/09/88 Fronts - nearshore
CH36 16/09/88 - 30/09/88 Fronts - mixing
CH56 08/07/89 - 22/07/89 Fronts - circulation
CH58 07/08/89 - 21/08/89 Fronts - mixing
CH38 24/10/88 - 31/10/88 Sandwaves
CH40 15/11/88 - 29/11/88 Sandbanks
CH42 15/12/88 - 29/12/88 Plumes/Sandbanks
CH46 12/02/89 - 26/02/89 Plumes/Sandwaves
CH44 13/01/89 - 27/01/89 Resuspension
CH52 11/05/89 - 24/05/89 Resuspension
CH60 06/09/89 - 19/09/89 Resuspension
CH48 13/03/89 - 27/03/89 Air/sea exchanges
CH62 05/10/89 - 19/10/89 Air/sea exchanges
CH50 12/04/89 - 25/04/89 Blooms/chemistry
CH54 09/06/89 - 22/06/89 Production

In addition to the main data collection period, a series of cruises took place between October 1989 and October 1990 that followed up work done on previous cruises (Table 3). Process studies relating to blooms, plumes (Humber, Wash and Rhine), sandwaves and the flux of contaminants through the Dover Strait were carried out as well as two `survey' cruises.

Table 3: Details of NSP `Follow up' cruises on RRS Challenger
Cruise No. Date Process
CH62A 23/10/89 - 03/11/89 Blooms
CH64 03/04/90 - 03/05/90 Blooms
CH65 06/05/90 - 17/05/90 Humber plume
CH66A 20/05/90 - 31/05/90 Survey
CH66B 03/06/90 - 18/06/90 Contaminants through Dover Strait
CH69 26/07/90 - 07/08/90 Resuspension/Plumes
CH72A 20/09/90 - 02/10/90 Survey
CH72B 04/10/90 - 06/10/90 Sandwaves/STABLE
CH72C 06/10/90 - 19/10/90 Rhine plume

The data collected during the observational phase of the North Sea Project comprised one of the most detailed sets of observations ever undertaken in any shallow shelf sea at that time.

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1989-04-14
End Date (yyyy-mm-dd) 1989-04-14
Organization Undertaking ActivityUniversity of Southampton Department of Oceanography (now University of Southampton School of Ocean and Earth Science)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierCH50_CTD_1707
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for CH50_CTD_1707

Sample reference number Nominal collection volume(l) Bottle rosette position Bottle firing sequence number Minimum pressure sampled (dbar) Maximum pressure sampled (dbar) Depth of sampling point (m) Bottle type Sample quality flag Bottle reference Comments
312201   10.00       54.50   54.60   51.20 Niskin bottle No problem reported    
312215   10.00       29.40   29.50   26.40 General Oceanics GO-FLO water sampler No problem reported    
312229   10.00       19.30   19.50   16.40 Niskin bottle No problem reported    
312232   10.00       11.20   11.50    8.40 General Oceanics GO-FLO water sampler No problem reported    
312246   10.00        7.30    7.40    4.40 Niskin bottle No problem reported    

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 Name CH50
Departure Date 1989-04-12
Arrival Date 1989-04-25
Principal Scientist(s)J Dennis Burton (University of Southampton Department of Oceanography)
Ship RRS Challenger

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Station NameNSP CTD Site EG
CategoryOffshore location
Latitude54° 20.72' N
Longitude0° 45.33' E
Water depth below MSL

North Sea Project CTD Site EG

Site EG was one of 123 North Sea Project CTD fixed stations.

Casts were performed by 11 cruises between 14/08/1988 and 01/10/1989, the measurements collected lie within a box bounded by co-ordinates 54.32622°N, 0.71711°E at the southwest corner and 54.3644°N, 0.79402°E at the northeast corner.

Related Fixed Station activities are detailed in Appendix 2

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

Appendix 1: CH50_CTD_1707

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.

Series IdentifierData CategoryStart date/timeStart positionCruise
1295470Water sample data1989-04-14 10:50:0054.33997 N, 0.75556 ERRS Challenger CH50
1663078Water sample data1989-04-14 10:50:0054.33997 N, 0.75556 ERRS Challenger CH50

Appendix 2: NSP CTD Site EG

Related series for this Fixed Station 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.

Series IdentifierData CategoryStart date/timeStart positionCruise
770005CTD or STD cast1988-08-14 23:36:0054.33567 N, 0.76333 ERRS Challenger CH33
822298CTD or STD cast1988-11-11 11:12:0054.3345 N, 0.76817 ERRS Challenger CH39
785981CTD or STD cast1989-01-01 06:54:0054.344 N, 0.72517 ERRS Challenger CH43
791937CTD or STD cast1989-02-07 11:03:0054.33783 N, 0.76783 ERRS Challenger CH45
793366CTD or STD cast1989-03-09 13:11:0054.33217 N, 0.75883 ERRS Challenger CH47
816084CTD or STD cast1989-04-14 04:35:0054.3565 N, 0.76067 ERRS Challenger CH50
816096CTD or STD cast1989-04-14 05:13:0054.356 N, 0.756 ERRS Challenger CH50
816103CTD or STD cast1989-04-14 10:43:0054.34 N, 0.7555 ERRS Challenger CH50
816115CTD or STD cast1989-04-14 14:32:0054.32617 N, 0.78433 ERRS Challenger CH50
1875266Water sample data1989-04-14 14:37:0054.32622 N, 0.78433 ERRS Challenger CH50
816127CTD or STD cast1989-04-14 18:41:0054.34967 N, 0.7385 ERRS Challenger CH50
1875278Water sample data1989-04-14 18:48:0054.34972 N, 0.73846 ERRS Challenger CH50
816140CTD or STD cast1989-04-15 04:26:0054.34367 N, 0.773 ERRS Challenger CH50
1875309Water sample data1989-04-15 04:31:0054.3436 N, 0.77296 ERRS Challenger CH50
816152CTD or STD cast1989-04-15 10:14:0054.36217 N, 0.75133 ERRS Challenger CH50
1875310Water sample data1989-04-15 10:22:0054.36214 N, 0.7514 ERRS Challenger CH50
816164CTD or STD cast1989-04-15 13:09:0054.34383 N, 0.77167 ERRS Challenger CH50
1875322Water sample data1989-04-15 13:14:0054.34375 N, 0.77171 ERRS Challenger CH50
816176CTD or STD cast1989-04-15 18:03:0054.35467 N, 0.794 ERRS Challenger CH50
1875334Water sample data1989-04-15 18:08:0054.35468 N, 0.79402 ERRS Challenger CH50
816232CTD or STD cast1989-04-16 13:02:0054.36433 N, 0.73833 ERRS Challenger CH50
1875383Water sample data1989-04-16 13:07:0054.3644 N, 0.73835 ERRS Challenger CH50
816244CTD or STD cast1989-04-16 18:36:0054.34467 N, 0.75167 ERRS Challenger CH50
1875395Water sample data1989-04-16 18:39:0054.34468 N, 0.75169 ERRS Challenger CH50
816268CTD or STD cast1989-04-17 04:58:0054.3605 N, 0.71717 ERRS Challenger CH50
1875414Water sample data1989-04-17 05:04:0054.36044 N, 0.71711 ERRS Challenger CH50
795742CTD or STD cast1989-05-07 20:39:0054.3325 N, 0.77183 ERRS Challenger CH51
1861596Water sample data1989-05-07 20:45:0054.33252 N, 0.77186 ERRS Challenger CH51
797109CTD or STD cast1989-06-05 04:56:0054.3325 N, 0.76817 ERRS Challenger CH53
1864139Water sample data1989-06-05 05:00:0054.33247 N, 0.7681 ERRS Challenger CH53
798499CTD or STD cast1989-07-05 09:05:0054.334 N, 0.76417 ERRS Challenger CH55
1657429Water sample data1989-07-05 09:12:0054.33408 N, 0.76424 ERRS Challenger CH55
1866700Water sample data1989-07-05 09:12:0054.33408 N, 0.76424 ERRS Challenger CH55
802297CTD or STD cast1989-09-02 08:58:0054.335 N, 0.7645 ERRS Challenger CH59
1856987Water sample data1989-09-02 09:02:0054.33504 N, 0.76454 ERRS Challenger CH59
800948CTD or STD cast1989-10-01 20:07:0054.3335 N, 0.76183 ERRS Challenger CH61
1855714Water sample data1989-10-01 20:12:0054.33353 N, 0.76177 ERRS Challenger CH61