Metadata Report for BODC Series Reference Number 1258926


Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
NameCategories
Niskin bottle  discrete water samplers
General Oceanics GO-FLO water sampler  discrete water samplers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr Reg Uncles
Originating Organization Plymouth Marine Laboratory
Processing Status banked
Project(s) North Sea Project 1987-1992
 

Data Identifiers

Originator's Identifier CH52_CTD_NUTS_4:1930
BODC Series Reference 1258926
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1989-05-16 22:11
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 52.63153 N ( 52° 37.9' N )
Longitude 3.62721 E ( 3° 37.6' E )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor Depth 6.5 m
Maximum Sensor Depth 25.3 m
Minimum Sensor Height 4.1 m
Maximum Sensor Height 22.9 m
Sea Floor Depth 29.4 m
Sensor Distribution Unspecified -
Sensor Depth Datum Unspecified -
Sea Floor Depth Datum Unspecified -
 

Parameters

BODC CODE Rank Units Short Title Title
ADEPZZ01 1 Metres DepBelowSurf Depth below surface of the water body
AMONFID2 1 Micromoles per litre NH4_0.4umFilt_Flowinjec Concentration of ammonium {NH4+ CAS 14798-03-9} per unit volume of the water body [dissolved plus reactive particulate <0.4/0.45um phase] by filtration and flow-injection analysis
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.

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.

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) 1989-05-16
End Date (yyyy-mm-dd) 1989-05-16
Organization Undertaking ActivityDunstaffnage Marine Laboratory (now Scottish Association for Marine Science)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierCH52_CTD_1930
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for CH52_CTD_1930

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
290790   10.00       28.70   28.80   25.30 General Oceanics GO-FLO water sampler No problem reported    
290800   10.00       16.30   16.80   13.20 Niskin bottle No problem reported    
290803   10.00        9.70    9.80    6.50 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.

Cruise

Cruise Name CH52
Departure Date 1989-05-11
Arrival Date 1989-05-24
Principal Scientist(s)Colin R Griffiths (Dunstaffnage Marine Laboratory)
Ship RRS Challenger

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameNSP Resusp. S
CategoryOffshore location
Latitude52° 40.20' N
Longitude3° 40.20' E
Water depth below MSL27.0 m

North Sea Project Resuspension Experiment Southern Site

This site was one of two contrasting North Sea sites occupied during the North Sea Project Resuspension Experiment.

The southern site was located in 27m of water and was characterised by a sandy bed and a permanently well-mixed water column.

The rigs deployed here lie within a box bounded by co-ordinates 52.652N 3.653E at the southwest corner and 52.670N 3.680E the northeast corner. Magnetic variation at this site was 3.0 degrees west.

Southern site deployment history is summarised below:

Rig ID Meter type Meter height Start date Data return (days) Comment
C44S

CM

TR

CM

TR

CM

TR

20.0m

20.0m

10.0m

10.0m

6.0m

5.0m

19/01/89

19/01/89

19/01/89

19/01/89

19/01/89

19/01/89

4.5

4.5

4.5

4.5

4.5

4.5

 
00351

TR

CM

CM

CM

CM

CM

TR

 

17.0m

 

11.0m

9.0m

6.0m

 

12/05/89

12/05/89

12/05/89

12/05/89

12/05/89

12/05/89

12/05/89

0.0

9.5

0.0

9.5

9.5

9.5

0.0

No data

N/A

No data

N/A

N/A

N/A

No data

00353

CM

CM

 

12/05/89

12/05/89

0.0

0.0

No data

No data

00354 TG   13/05/89 0.0 No data
00355
(STABLE)

TR

CM

PR

1.2m

0.5m

0.5m

12/05/89

12/05/89

12/05/89

10.0

6.0

6.0

 
00356 MET 30.0m 12/05/89 9.4  
00357 WV 30.0m 12/05/89 9.5  
00419 ADCP 0.8m 10/09/89 4.8  
00420

CM

TR

CM

TR

CM

TR

21.0m

20.0m

10.0m

9.0m

5.0m

4.0m

10/09/89

10/09/89

10/09/89

10/09/89

10/09/89

10/09/89

5.2

5.2

5.2

5.2

5.2

5.2

 

ADCP = Acoustic Doppler Current Profiler
CM = Current Meter
PR = Pressure Recorder
TR = Transmissometer
TG = Tide Gauge
WV = Wave Rider
MET = Met. Buoy

Other Series linked to this Fixed Station for this cruise - 816650 816662 816674 816686 816698 816705 816717 816729 816730 816914 816926 816938 816951 816963 816975 816987 816999 817002 817014 817026 817038 817051 817063 817075 817087 817099 817106 817118 817131 817143 817155 817167 817179 817180 817192 817211 817223 817235 817247 817259 817260 817272 817284 817296 817303 817315 817456 817468 817481 817493 817500 817512 817524 817536 817548 817561 817573 817585 817597 817604 817616 817628 817641 817653 817665 817677 817689 817690 817708 817721 817733 817745 1258489 1258490 1258545 1258557 1258582 1258601 1258613 1258637 1258809 1258810 1258822 1258834 1258846 1258858 1258871 1258883 1258895 1258902 1258914 1258938 1258951 1258963 1258975 1258987 1258999 1259002 1259014 1259026 1259038 1259051 1259063 1259075 1259087 1259099 1259106 1259118 1259131 1259143 1259155 1259340 1259352 1259364 1259376 1259388 1259407 1259420 1259432 1259444 1259456 1259468 1259481 1259493 1259500 1259512 1259524

Other Cruises linked to this Fixed Station (with the number of series) - CH44 (24) CH60 (66)


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