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Metadata Report for BODC Series Reference Number 1246372

Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
Niskin bottle  discrete water samplers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr David Hydes
Originating Organization Institute of Oceanographic Sciences Deacon Laboratory (now National Oceanography Centre, Southampton)
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 CH57_CTD_NUTS_12:2487
BODC Series Reference 1246372

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1989-08-03 17:44
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -

Spatial Co-ordinates

Latitude 55.49466 N ( 55° 29.7' N )
Longitude 1.19212 W ( 1° 11.5' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth 0.5 m
Maximum Sensor or Sampling Depth 82.8 m
Minimum Sensor or Sampling Height 7.6 m
Maximum Sensor or Sampling Height 89.9 m
Sea Floor Depth 90.4 m
Sea Floor Depth Source -
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
AMONAATX1Micromoles per litreConcentration of ammonium {NH4+ CAS 14798-03-9} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
BOTTFLAG1Not applicableSampling process quality flag (BODC C22)
NTRIAATX1Micromoles per litreConcentration of nitrite {NO2- CAS 14797-65-0} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
NTRZAATX1Micromoles per litreConcentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
PHOSAATX1Micromoles per litreConcentration of phosphate {PO43- CAS 14265-44-2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
SAMPRFNM1DimensionlessSample reference number
SLCAAATX1Micromoles per litreConcentration of silicate {SiO44- CAS 17181-37-2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis

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 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.

Nutrients as part of the North Sea Project

Document History

Converted from CDROM documentation.

Sampling strategy and methodology

Survey cruises

Duplicate samples were collected in 30 ml 'Elkay Dilu-Vials' from each CTD bottle. Samples were stored in a refrigerator at 4°C between collection and analysis and usually analysed within four hours of collection. Initially, two aliquots from one the samples were analysed. If a problem was considered to have occurred, the second sample was analysed. The samples were unfiltered and no preservative was added.

The samples were analysed using a ChemLab AA-II segmented continuous flow autoanalyser. The chemistries used were similar to those described in Grasshof et al (1983). Peak heights were interpreted using a ChemLab PHA interface and software running on an IBM PS2/50. Each run was calibrated by measurement of a set of 4 standards run in duplicate at the start of the run to which a third order polynomial, forced to pass through the origin, was fitted.

Analyses were made for nitrate+nitrite, nitrate, phosphate, silicon and (for Challenger 39 and subsequent cruises), ammonia.

The replicate analyses were supplied to BODC. Values were subjected to a simple range check with seasonally varying tolerances and a check was made to identify samples with excessive differences between replicates. Any problems identified were resolved by interaction with the Principal Investigator and erroneous values corrected or deleted from the data set. All remaining replicates were then averaged.

In general, the autoanalyser worked well. The only problems reported were random variations in Cu/Cd reduction coil efficiency (between 70 and 90%) on two cruises (Challenger 33 and Challenger 72A) and occasional baseline drift and spiking, mostly on phosphate and nitrite.

During Challenger 33, problems were encountered with the PS2 processing software and the nutrient concentrations were obtained by manual determination of peak heights from chart recorder output.

The survey data set is believed to be of good quality and has borne up well to intercomparison with data from other sources during the compilation of synthesised data sets by the ICES hydrographer.

Process cruises

Analyses for the major nutrients (nitrate+nitrite, phosphate, nitrite and silicate) were undertaken on CTD water bottle samples for the following process cruises: Challenger 44, Challenger 48, Challenger 50, Challenger 52, Challenger 60, Challenger 62 and Challenger 72C.

For Challenger 50 and Challenger 72C the survey protocols, including the determination of ammonia, were followed exactly by an analyst who had also participated in survey cruises. Quality control was undertaken by the analyst prior to submission to BODC and the data are believed to be of the same good quality as the survey data.

For the resuspension cruises, Challenger 44, Challenger 52 and Challenger 60, the survey protocols were generally followed except the concentrations were computed manually and all quality control was done prior to submission to BODC. The analyst had participated in survey cruises.

On two of these cruises, Challenger 52 and Challenger 60 ammonia was determined by flow injection analysis. The method is based upon the conversion of the ammonium ion into gaseous ammonia across a hydrophobic membrane and is fully described in Willason and Johnson (1986) and Howland et al.

There are no reasons to suspect the quality of the data from these cruises.

For Challenger 48 and 62 the analyses were done using the same equipment but details of the protocols followed, including quality control procedures, are unknown.

Feedback to BODC indicates that the nitrate data from Challenger 48 appear to be high by up to a factor of 10 and that the phosphate data do not exhibit the expected relationships with other parameters. However, it is not possible to categorically state that the data are in error because the cruises were working in waters strongly influenced by the Rhine plume.

WARNING. It is strongly recommended that the nutrient data from Challenger 48 and Challenger 62 be used with caution.


Grasshof, K., Erhardt, M. and Kremling, K. (1983). Methods of sea water analysis, 2nd edition. Verlag Chemie, Weinheim, 419pp..

Howland, R.J.M., A.J. Bale and P.G. Watson. Plymouth Marine Laboratory Estuarine Processes Group Analytical Methods Handbook.

Willason, S.W. and K.S. Johnson (1986). A rapid, highly sensitive technique for the determination of ammonia in sea water. Mar. Biol. 91, 285-290.

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) 1989-08-03
End Date (yyyy-mm-dd) 1989-08-03
Organization Undertaking ActivityUniversity of Wales, Bangor School of Ocean Sciences (now Bangor University School of Ocean Sciences)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierCH57_CTD_2487
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for CH57_CTD_2487

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
308497   10.00       87.50   87.90   82.80 Niskin bottle No problem reported    
308513   10.00       65.10   65.80   60.70 Niskin bottle No problem reported    
308527   10.00       31.90   33.10   28.10 Niskin bottle No problem reported    
308530   10.00       17.50   17.80   13.40 Niskin bottle No problem reported    
308544   10.00        3.10    3.40     .50 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 CH57
Departure Date 1989-07-24
Arrival Date 1989-08-06
Principal Scientist(s)Paul Tett (University of Wales, Bangor School of Ocean Sciences)
Ship RRS Challenger

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Station NameNSP CTD Site CX
CategoryOffshore location
Latitude55° 29.90' N
Longitude1° 11.62' W
Water depth below MSL

North Sea Project CTD Site CX

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

Casts were performed by 18 cruises between 06/05/1988 and 30/09/1990, the measurements collected lie within a box bounded by co-ordinates 55.49466°N, -1.20432°E at the southwest corner and 55.50188°N, -1.8289°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: CH57_CTD_2487

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
1709822Water sample data1989-08-03 17:44:0055.49466 N, 1.19212 WRRS Challenger CH57
1865192Water sample data1989-08-03 17:44:0055.49466 N, 1.19212 WRRS Challenger CH57

Appendix 2: NSP CTD Site CX

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
781709CTD or STD cast1988-05-14 03:38:0052.60967 N, 4.32033 ERRS Challenger CH28
769747CTD or STD cast1988-08-12 20:57:0055.50183 N, 1.2015 WRRS Challenger CH33
783845CTD or STD cast1988-09-11 08:48:0055.50167 N, 1.204 WRRS Challenger CH35
784707CTD or STD cast1988-10-10 19:59:0055.501 N, 1.198 WRRS Challenger CH37
822028CTD or STD cast1988-11-09 03:42:0055.497 N, 1.19467 WRRS Challenger CH39
785366CTD or STD cast1988-12-08 16:47:0055.49667 N, 1.2015 WRRS Challenger CH41
786161CTD or STD cast1989-01-02 12:49:0055.49833 N, 1.19167 WRRS Challenger CH43
791716CTD or STD cast1989-02-05 22:38:0055.50067 N, 1.1985 WRRS Challenger CH45
793250CTD or STD cast1989-03-08 07:46:0055.50133 N, 1.20067 WRRS Challenger CH47
1857991Water sample data1989-03-08 07:50:0055.5014 N, 1.20062 WRRS Challenger CH47
794369CTD or STD cast1989-04-07 05:12:0055.4975 N, 1.19883 WRRS Challenger CH49
1859045Water sample data1989-04-07 05:18:0055.49756 N, 1.19878 WRRS Challenger CH49
795453CTD or STD cast1989-05-05 10:49:0055.50183 N, 1.20433 WRRS Challenger CH51
2082553Water sample data1989-05-05 10:57:4155.50188 N, 1.20432 WRRS Challenger CH51
2097343Water sample data1989-05-05 10:57:4155.50188 N, 1.20432 WRRS Challenger CH51
1861283Water sample data1989-05-05 10:58:0055.50188 N, 1.20432 WRRS Challenger CH51
796837CTD or STD cast1989-06-03 05:12:0055.50017 N, 1.19967 WRRS Challenger CH53
1863867Water sample data1989-06-03 05:17:0055.50009 N, 1.19961 WRRS Challenger CH53
798113CTD or STD cast1989-07-02 02:30:0055.49833 N, 1.2 WRRS Challenger CH55
1657036Water sample data1989-07-02 02:38:0055.49841 N, 1.19997 WRRS Challenger CH55
1866318Water sample data1989-07-02 02:38:0055.49841 N, 1.19997 WRRS Challenger CH55
799534CTD or STD cast1989-08-03 17:39:0055.49467 N, 1.19217 WRRS Challenger CH57
1709822Water sample data1989-08-03 17:44:0055.49466 N, 1.19212 WRRS Challenger CH57
1865192Water sample data1989-08-03 17:44:0055.49466 N, 1.19212 WRRS Challenger CH57
801988CTD or STD cast1989-08-31 01:59:0055.4975 N, 1.19783 WRRS Challenger CH59
1856686Water sample data1989-08-31 02:04:0055.49756 N, 1.19777 WRRS Challenger CH59
800659CTD or STD cast1989-09-29 16:59:0055.498 N, 1.1985 WRRS Challenger CH61
1855425Water sample data1989-09-29 17:05:0055.49799 N, 1.19843 WRRS Challenger CH61
2086818Water sample data1989-09-29 17:05:1155.49799 N, 1.19843 WRRS Challenger CH61
2087883Water sample data1989-09-29 17:05:1155.49799 N, 1.19843 WRRS Challenger CH61
803368CTD or STD cast1990-05-29 03:15:0055.50083 N, 1.20017 WRRS Challenger CH66A
805154CTD or STD cast1990-09-30 14:32:0055.49883 N, 1.20167 WRRS Challenger CH72A