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Metadata Report for BODC Series Reference Number 1251583


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 Mr Malcolm Woodward
Originating Organization Plymouth Marine Laboratory
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) -
 

Data Identifiers

Originator's Identifier DI241_CTD_NUTS_62:CTD16
BODC Series Reference 1251583
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1999-06-18 00:02
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 58.87699 N ( 58° 52.6' N )
Longitude 3.05009 E ( 3° 3.0' E )
Positional Uncertainty Unspecified
Minimum Sensor or Sampling Depth 4.3 m
Maximum Sensor or Sampling Depth 99.6 m
Minimum Sensor or Sampling Height 20.3 m
Maximum Sensor or Sampling Height 115.6 m
Sea Floor Depth 119.9 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
AMONNATX1Micromoles per litreConcentration (nM sensitivity) of ammonium {NH4+ CAS 14798-03-9} per unit volume of the water body [dissolved plus reactive particulate phase] by nanomolar ammonium system after Jones (1991)
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
NTRZNNTX1Micromoles per litreConcentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate phase] by nanomolar Nox system after Garside (1982)
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

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.

Micro- and nanomolar-sensitivity nutrient analysis on cruise RRS Discovery DI241

Document History

Converted from CDROM documentation

Data Originator

Malcolm Woodward

Content of data series

Parameter Code Unit Samples
Dissolved ammonia (unfiltered)-nanomolar analyser AMONNATX µmol l-1 314
Dissolved nitrite (unfiltered) NTRIAATX µmol l-1 369
Dissolved nitrate + nitrite (unfiltered) - Technicon analyser NTRZAATX µmol l-1 362
Dissolved nitrate + nitrite (unfiltered) - nanomolar NOx analyser NTRZNNTX µmol l-1 183
Dissolved phosphate (unfiltered) PHOSAATX µmol l-1 369
Dissolved silicate (unfiltered) SLCAAATX µmol l-1 369

Sampling strategy and methodology

Water samples were subsampled directly from the CTD bottles into clean Nalgene bottles. Analysis was carried out on board ship, and completed within 2 hours of sampling in every case.

Inorganic nutrient concentrations were determined using a 5-channel Technicon AAII, segmented flow analyser. The methodologies used for each nutrient followed those of Brewer and Riley (1965) for nitrate, Grasshoff (1976) for nitrite, Kirkwood (1989) for phosphate and silicate, and Mantoura and Woodward (1983) for ammonia.

As ammonia concentrations dropped below the detection limits for the colorimetric system, a nanomolar Ammonia analysis system (adapted from Jones, 1991) was used. Similarly, samples which had nitrate + nitrite concentrations below the detection limit of the Technicon method were analysed using the nanomolar chemiluminescence system (Garside, 1982). The two different methods used for analysis of nitrate + nitrite are indicated in the parameter codes.

References

Brewer, P.G. and Riley, J.P., 1965. The automatic determination of nitrate in seawater. Deep-Sea Research, 12, 765-772.

Garside, C., 1982. A chemiluminescent technique for the determination of nanomolar concentrations of nitrate and nitrite in seawater. Marine Chemistry, 11, 159-167.

Grasshoff, K., 1976. Methods of seawater analysis. Verlag Chemie, Weiheim. 317pp

Jones, R.D., 1991. An improved fluorescence method for the determination of nanomolar concentrations of ammonium in natural waters. Limnology and Oceanography, 36, 814-819.

Kirkwood, D., 1989. Simultaneous determination of selected nutrients in sea water. International Council for the Exploration of the Sea (ICES), CM 1989/C:29.

Mantoura, R.F.C. and Woodward, E.M.S., 1983. Optimisation of the indophenol blue method for the automated determination of ammonia in estuarine waters. Estuarine, Coastal and Shelf Science, 17, 219-224.


Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1999-06-17
End Date (yyyy-mm-dd) 1999-06-18
Organization Undertaking ActivityPlymouth Marine Laboratory
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierDI241_CTD_CTD16
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for DI241_CTD_CTD16

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
108278   30.00       43.00   44.00   42.20 Niskin bottle No problem reported    
108279   30.00       75.40   76.60   74.40 Niskin bottle No problem reported    
108280   30.00       50.10   51.50   49.40 Niskin bottle No problem reported    
108281   30.00       29.80   31.20   29.30 Niskin bottle No problem reported    
108282   30.00       22.20   22.90   21.40 Niskin bottle No problem reported    
108283   30.00       20.00   20.70   19.30 Niskin bottle No problem reported    
108284   30.00       17.90   18.50   17.10 Niskin bottle No problem reported    
108285   30.00       15.00   15.70   14.30 Niskin bottle No problem reported    
108286   30.00       10.00   10.70    9.40 Niskin bottle No problem reported    
108287   30.00        4.90    5.60    4.30 Niskin bottle No problem reported    
108667   30.00      100.90  102.00   99.60 Niskin bottle No problem reported    
108668   30.00       24.90   25.70   24.20 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 D241
Departure Date 1999-06-04
Arrival Date 1999-07-01
Principal Scientist(s)Peter H Burkill (Plymouth Marine Laboratory)
Ship RRS Discovery

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