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Metadata Report for BODC Series Reference Number 1351037


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 Prof Toby Sherwin
Originating Organization Scottish Association for Marine Science
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) -
 

Data Identifiers

Originator's Identifier CD176_CTD_NUTS_126:C036
BODC Series Reference 1351037
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2005-10-18 16:59
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 63.14130 N ( 63° 8.5' N )
Longitude 19.90887 W ( 19° 54.5' W )
Positional Uncertainty Unspecified
Minimum Sensor or Sampling Depth 8.5 m
Maximum Sensor or Sampling Depth 1017.0 m
Minimum Sensor or Sampling Height 11.0 m
Maximum Sensor or Sampling Height 1019.5 m
Sea Floor Depth 1028.0 m
Sea Floor Depth Source -
Sensor or Sampling Distribution Unspecified -
Sensor or Sampling Depth Datum Unspecified -
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODERankUnitsTitle
ADEPZZ011MetresDepth (spatial coordinate) relative to water surface in the water body
AMONAAD11Micromoles per litreConcentration of ammonium {NH4+ CAS 14798-03-9} per unit volume of the water body [dissolved plus reactive particulate
BOTTFLAG1Not applicableSampling process quality flag (BODC C22)
FIRSEQID1DimensionlessBottle firing sequence number
NTRIAAD11Micromoles per litreConcentration of nitrite {NO2- CAS 14797-65-0} per unit volume of the water body [dissolved plus reactive particulate
NTRZAAD11Micromoles per litreConcentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate
PHOSAAD11Micromoles per litreConcentration of phosphate {PO43- CAS 14265-44-2} per unit volume of the water body [dissolved plus reactive particulate
ROSPOSID1DimensionlessBottle rosette position identifier
SAMPRFNM1DimensionlessSample reference number
SDAMAAD11Micromoles per litreConcentration standard deviation of ammonium {NH4+ CAS 14798-03-9} per unit volume of the water body [dissolved plus reactive particulate
SDNIAAD11Micromoles per litreConcentration standard deviation of nitrite {NO2- CAS 14797-65-0} per unit volume of the water body [dissolved plus reactive particulate
SDNZAAD11Micromoles per litreConcentration standard deviation of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate
SDPHAAD11Micromoles per litreConcentration standard deviation of phosphate {PO43- CAS 14265-44-2} per unit volume of the water body [dissolved plus reactive particulate
SDSLAAD11Micromoles per litreConcentration standard deviation of silicate {SiO44- CAS 17181-37-2} per unit volume of the water body [dissolved plus reactive particulate
SLCAAAD11Micromoles per litreConcentration of silicate {SiO44- CAS 17181-37-2} per unit volume of the water body [dissolved plus reactive particulate

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

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.

CD176 Discrete Dissolved Inorganic Nutrients Sampling Document

Originator's Protocol for Data Acquisition and Analysis

Water samples were collected from CTD stations throughout the cruise for the analysis of dissolved inorganic nutrients using an onboard Lachet Quickchem 8000 colorimetric flow injection autoanalyser. Shortly after the cruise started a fault developed with the autosampler, which prevented further onboard analysis. Subsequent samples were collected and filtered through GF/F 0.7 µm filters, before being frozen for analysis back at SAMS.

References Cited

Sherwin, T. A. et al, (2005) 'Cruise CD176 Birkenhead to Falmouth via Rockall, Iceland and Oban', Internal Report No 248, Scottish Association for Marine Science.

Available - Cruise CD176 Internal Report

BODC Data Processing Procedures

The nutrient data were supplied to BODC in Microsoft Excel spreadsheets. Values were extracted from these and loaded into BODC's ocean database under an ORACLE Relational Database Management System. Data that were considered unrealistic were flagged suspect.

Several inconsistencies were noted between the cruise report CTD logsheets and the originator spreadsheets relating to particular Niskin bottles sampled. In all cases the uncertainty involves multiple bottles fired at the same depth, so assignment to bottle numbers was deemed somewhat arbitrary.

Data listed out from the BODC database are done so at a resolution deemed appropriate for that particular variable and the analytical procedure involved. In some instances this results in the listing out of zero values.

SAMS nitrate data quality warning

SAMS have notified BODC of a problem in the analytical procedure adopted for nitrate analysis on this cruise. The problem relates to the technique used to prepare the analytical standards, which results in nitrate (and consequently nitrite) values which are typically 10-15 % higher than they should be. Absolute data values should therefore be used with extreme caution.

Content of data series

Originator's Parameter Unit Description BODC Parameter code BODC Unit Comments
Nitrate and nitrite µmol/l Concentration of nitrate and nitrite in the water column by colorimetric autoanalysis (unfiltered) NTRZAATX µmol/l n/a
Standard deviation of nitrate and nitrite µmol/l Concentration standard deviation of nitrate and nitrite in the water column by colorimetric autoanalysis (unfiltered) SDNZAATX µmol/l n/a
Phosphate µmol/l Concentration of phosphate in the water column by colorimetric autoanalysis (unfiltered) PHOSAATX µmol/l n/a
Standard deviation of phosphate µmol/l Concentration standard deviation of phosphate in the water column by colorimetric autoanalysis (unfiltered) SDPHAATX µmol/l n/a
Silicate µmol/l Concentration of silicate in the water column by colorimetric autoanalysis (unfiltered) SLCAAATX µmol/l n/a
Standard deviation of silicate µmol/l Concentration standard deviation of silicate in the water column by colorimetric autoanalysis (unfiltered) SLSDAATX µmol/l n/a
Nitrite µmol/l Concentration of nitrite in the water body by filtration and colorimetric autoanalysis NTRIAAD1 µmol/l n/a
Standard deviation of nitrite µmol/l Concentration standard deviation of nitrite in the water column by filtration and colorimetric autoanalysis SDNIAAD1 µmol/l n/a
Nitrate and nitrite µmol/l Concentration of nitrate and nitrite in the water column by filtration and colorimetric autoanalysis NTRZAAD1 µmol/l n/a
Standard deviation of nitrate and nitrite µmol/l Concentration standard deviation of nitrate and nitrite in the water column by filtration and colorimetric autoanalysis SDNZAAD1 µmol/l n/a
Ammonium µmol/l Concentration of ammonium in the water column by filtration and colorimetric autoanalysis AMONAAD1 µmol/l n/a
Standard deviation of ammonium µmol/l Concentration standard deviation of ammonium in the water column by filtration and colorimetric autoanalysis SDAMAAD1 µmol/l n/a
Phosphate µmol/l Concentration of phosphate in the water column by filtration and colorimetric autoanalysis PHOSAAD1 µmol/l n/a
Standard deviation of phosphate µmol/l Concentration standard deviation of phosphate in the water column by filtration and colorimetric autoanalysis SDPHAAD1 µmol/l n/a
Silicate µmol/l Concentration of silicate in the water column by filtration and colorimetric autoanalysis SLCAAAD1 µmol/l n/a
Standard deviation of silicate µmol/l Concentration standard deviation of silicate in the water column by filtration and colorimetric autoanalysis SDSLAAD1 µmol/l n/a

Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2005-10-18
End Date (yyyy-mm-dd) 2005-10-18
Organization Undertaking ActivityScottish Association for Marine Science
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierCD176_CTD_C036
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for CD176_CTD_C036

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
203729   1 1 1029.00 1030.00 1017.00 Niskin bottle No problem reported    
203730   2 2  802.20  803.20  793.40 Niskin bottle No problem reported    
203731   3 3  597.30  598.30  591.20 Niskin bottle No problem reported    
203732   4 4  399.20  400.20  395.50 Niskin bottle No problem reported    
203733   5 5  203.90  204.90  202.30 Niskin bottle No problem reported    
203734   6 6  102.70  103.70  102.20 Niskin bottle No problem reported    
203735   7 7   53.00   54.00   53.00 Niskin bottle No problem reported    
203736   8 8   33.10   34.10   33.30 Niskin bottle No problem reported    
203737   9 9   17.90   18.90   18.20 Niskin bottle No problem reported    
203738   10 10    8.10    9.10    8.50 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 CD176
Departure Date 2005-10-06
Arrival Date 2005-11-01
Principal Scientist(s)Toby J Sherwin (Scottish Association for Marine Science)
Ship RRS Charles Darwin

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