Metadata Report for BODC Series Reference Number 1247209


Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
NameCategories
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
Project(s) North Sea Project 1987-1992
 

Data Identifiers

Originator's Identifier CH55_CTD_NUTS_12:2280
BODC Series Reference 1247209
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1989-06-29 13:51
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 54.19263 N ( 54° 11.6' N )
Longitude 7.46577 E ( 7° 27.9' E )
Positional Uncertainty Unspecified
Minimum Sensor Depth 1.3 m
Maximum Sensor Depth 35.4 m
Minimum Sensor Height 2.5 m
Maximum Sensor Height 36.6 m
Sea Floor Depth 37.9 m
Sensor Distribution Unspecified -
Sensor Depth Datum Unspecified -
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODE Rank Units Short Title Title
ADEPZZ01 1 Metres DepBelowSurf Depth below surface of the water body
AMONAATX 1 Micromoles per litre NH4_Unfilt_Col Concentration of ammonium {NH4+ CAS 14798-03-9} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
BOTTFLAG 1 Dimensionless C22_flag Sampling process quality flag (BODC C22)
NTRIAATX 1 Micromoles per litre NO2_Unfilt_ColAA Concentration of nitrite {NO2- CAS 14797-65-0} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
NTRZAATX 1 Micromoles per litre NO3+NO2_Unfilt_ColAA Concentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
PHOSAATX 1 Micromoles per litre PO4_Unfilt_ColAA Concentration of phosphate {PO43- CAS 14265-44-2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
SAMPRFNM 1 Dimensionless SampRef Sample reference number
SLCAAATX 1 Micromoles per litre SiOx_Unfilt_ColAA Concentration of silicate {SiO44- CAS 17181-37-2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
 

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.

Deployment

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.

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.

References

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:

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) 1989-06-29
End Date (yyyy-mm-dd) 1989-06-29
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 IdentifierCH55_CTD_2280
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for CH55_CTD_2280

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
300644   10.00       38.00   39.70   35.40 Niskin bottle No problem reported    
300658   10.00       12.00   12.60    9.00 Niskin bottle No problem reported    
300661   10.00        4.20    4.80    1.30 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.

Other Series linked to this Data Activity - 1656764

Cruise

Cruise Name CH55
Departure Date 1989-06-24
Arrival Date 1989-07-07
Principal Scientist(s)John H Simpson (University of Wales, Bangor School of Ocean Sciences)
Ship RRS Challenger

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