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Metadata Report for BODC Series Reference Number 1868270


Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
NameCategories
Niskin bottle  discrete water samplers
Instrument Mounting lowered unmanned submersible
Originating Country Belgium
Originator Dr Michel Frankignoulle
Originating Organization University of Liège Department of Astrophysics Geophysics and Oceanography
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) -
 

Data Identifiers

Originator's Identifier BG9309_CTD_DOXY_69:GC11
BODC Series Reference 1868270
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1993-04-29 18:10
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 42.16787 N ( 42° 10.1' N )
Longitude 9.49169 W ( 9° 29.5' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth 4.6 m
Maximum Sensor or Sampling Depth 396.1 m
Minimum Sensor or Sampling Height 823.9 m
Maximum Sensor or Sampling Height 1215.4 m
Sea Floor Depth 1220.0 m
Sea Floor Depth Source PEVENT
Sensor or Sampling Distribution Unspecified -
Sensor or Sampling Depth Datum Unspecified -
Sea Floor Depth Datum Unspecified -
 

Parameters

BODC CODERankUnitsTitle
ADEPZZ011MetresDepth (spatial coordinate) relative to water surface in the water body
BOTTFLAG1Not applicableSampling process quality flag (BODC C22)
DOXYWITX1Micromoles per litreConcentration of oxygen {O2 CAS 7782-44-7} per unit volume of the water body [dissolved plus reactive particulate phase] by Winkler titration
SAMPRFNM1DimensionlessSample reference number

Definition of BOTTFLAG

BOTTFLAGDefinition
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

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

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.

Dissolved Oxygen for cruises Belgica BG9309, BG9322, BG9412, BG9506, BG9521 and BG9522

Document History

Converted from CDROM documentation.

Content of data series

DOXYPR01 Beckman oxygen
Beckman oxygen probe
Micromoles/litre
DOXYWITX Winkler oxygen
Winkler titration
Micromoles/litre
OXYSBB01 Oxygen saturation (Bens.Kr./Beckman)
Benson and Krause algorithm from Beckman data
Per Cent

Data Originator

Dr Michel Frankignoulle, University of Liege, Belgium.

Sampling strategy and methodology

Water samples taken from CTD rosette bottles were analysed using the classical Winkler technique using a Metrohm automatic titration system.

Comments on data quality

Cruise Belgica BG9506

The Winkler oxygen data from this cruise are exceptionally low with surface saturations of 90 per cent or less and values in the oxygen minimum below 180 µM. Compared to data from the same area at the same time of year (1993 and 1994), the data are systematically low by 10 per cent. The CTD data, prior to calibration against the bottle data, look as expected with surface saturations scattered around 100 per cent and values in the oxygen minimum of 190-200 µM.

The conclusion from examination of the data is that there is a systematic error in the bottle data from this cruise. Consequently, all bottle data have been flagged suspect and no bottle calibration has been applied to the CTD data.

Cruises Belgica BG9521 and BG9522

The CTD oxygen data from these cruises were detrimentally affected by temperature gradients in the water column and the oxygen sensor appeared slow to equilibrate. Empirical correction on a cast by cast basis was attempted for BG9521 but there were insufficient bottle data to do this for BG9522 and all shallow (above 200m) CTD oxygen data from this cruise have been jettisoned.

The shallow CTD derived values from BG9521 should be used with caution and wherever possible the Winkler data should be used instead. The deep CTD data from both cruises are of better quality. See the CTD data documents from these cruises for further details.

References

Aminot, A. and Chaussepied, M. (eds), 1983. Manuel des analyses chimiques en milieau marin. C.N. L'Exploitation des Oceans. 395 pp.

Benson, B.B., Krause D. (1984). The concentration and isotopic fractionation of oxygen dissolved in fresh water and sea water in equilibrium with the atmosphere. Limnol.Oceanogr., 29, 620-632.


Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1993-04-29
End Date (yyyy-mm-dd) 1993-04-29
Organization Undertaking ActivityFree University of Brussels, Laboratory of Chemical Oceanography and Water Geochemistry
Country of OrganizationBelgium
Originator's Data Activity IdentifierBG9309_CTD_GC11
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for BG9309_CTD_GC11

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
555273   10.00         .20    1.80     .60 Niskin bottle No problem reported    
555274   10.00        4.30    5.80    4.60 Niskin bottle No problem reported    
555275   10.00        9.30   10.80    9.60 Niskin bottle No problem reported    
555276   10.00       49.30   50.80   49.30 Niskin bottle No problem reported    
555277   10.00      139.30  140.80  138.50 Niskin bottle No problem reported    
558619   10.00       19.30   20.80   19.50 Niskin bottle No problem reported    
558620   10.00       29.30   30.80   29.40 Niskin bottle No problem reported    
558622   10.00       79.30   80.80   79.00 Niskin bottle No problem reported    
558623   10.00       99.30  100.80   98.80 Niskin bottle No problem reported    
558625   10.00      199.30  200.80  198.00 Niskin bottle No problem reported    
558626   10.00      299.30  300.80  297.10 Niskin bottle No problem reported    
558627   10.00      399.30  400.80  396.10 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

Cruise Name BG9309
Departure Date 1993-04-19
Arrival Date 1993-05-06
Principal Scientist(s)Roland Wollast (Free University of Brussels, Laboratory of Chemical Oceanography and Water Geochemistry)
Ship RV Belgica

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
Q value below limit of quantification

Appendix 1: BG9309_CTD_GC11

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
1266084Water sample data1993-04-29 18:10:0042.16787 N, 9.49169 WRV Belgica BG9309
1662597Water sample data1993-04-29 18:10:0042.16787 N, 9.49169 WRV Belgica BG9309
1852058Water sample data1993-04-29 18:10:0042.16787 N, 9.49169 WRV Belgica BG9309
1868350Water sample data1993-04-29 18:10:0042.16787 N, 9.49169 WRV Belgica BG9309