Metadata Report for BODC Series Reference Number 1280747


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
Project(s) -
 

Data Identifiers

Originator's Identifier CD132_CTD_NUTS_62:CD132_061
BODC Series Reference 1280747
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2001-09-26 08:28
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 26.00157 N ( 26° 0.1' N )
Longitude 56.58225 E ( 56° 34.9' E )
Positional Uncertainty Unspecified
Minimum Sensor Depth 0.7 m
Maximum Sensor Depth 91.3 m
Minimum Sensor Height 4.7 m
Maximum Sensor Height 95.3 m
Sea Floor Depth 96.0 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.

Dissolved nutrient data series for cruise Charles Darwin CD132

Content of Data Series

Parameter Unit Parameter Code Number of stations Comments
Ammonium µmol/l AMONAATX 322 None
Ammonium (nanomolar system) µmol/l AMONNATX 71 None
Nitrate+Nitrite (LWCC) µmol/l NTRZLWTX 50 None
Nitrate+Nitrite µmol/l NTRZAATX 567 None
Nitrite µmol/l NTRIAATX 558 None
Phosphate µmol/l PHOSAATX 561 None
Silicate µmol/l SLCAAATX 556 None

Originator's Protocol for Data Acquisition and Analysis

The following methodology was compiled from information extracted from the CD132 cruise report (Burkill 2002) and from information provided by the originator.

Samples for nutrient analyses were collected from water sampled using the CTD rosette system equipped with 24x20L Niskin sampling bottles. Samples were collected at 36 CTD stations including pre-dawn casts (biogeochemistry, primary production, and nitrogen uptake and regeneration experiments) generally down to 300m, deep casts down to 2500m and mid-day high vertical resolution sampling casts.

Water samples were sub-sampled into acid-cleaned 60 ml HDPE (Nalgene) bottles. Analysis for the nutrient samples was in every case complete within 3 hours of sampling. Clean handling techniques were employed to avoid any contamination of the samples, particularly by ammonium. Samples were analysed without pre-filtration. No samples were stored.

The nutrient analyser was the five-channel Technicon AAII segmented flow autoanalyser. The chemical methodologies used were according to Brewer and Riley (1965) for nitrate, Grasshoff (1976) for nitrite, Kirkwood (1989) for phosphate and silicate, and Mantoura and Woodward (1983) for ammonium.

The nanomolar ammonium system is an adaptation from Jones (1991) which uses a fluorescence analysis technique following ammonia gas diffusion out of the samples, passing across a hydrophobic teflon membrane due to pH differential chemistry.

All CTD samples were analysed with a negligible sample loss rate. The ageing Technicon 5-channel system showed its reliability and reproducibility in the extreme environment of tropical, on-board deployment.

The ammonium fluorescence system performed well early in the cruise before developing a severe loss of sensitivity, which was diagnosed as a fluorometer problem. The system was inoperable for the second half of the cruise and the colorimetric system using the Technicon auto-analyser was used for the remainder of the cruise with good performance.

This cruise was the first deployment of a new unique multi-channel nanomolar analyser combining the segmented flow colorimetric analytical techniques with a Liquid Waveguide Capillary Cell (LWCC). The system is still essentially a developmental analyser. Of the two channels available during the cruise, one was used for the analysis of nitrate and nitrite while the other channel was used to develop the phosphate system into an operational unit. The nitrate channel operated successfully at a sensitivity of about 1 nanomole or better and performed well for the majority of the cruise. Due to lack of time and modern high-precision equipment, it was not possible to make the phosphate channel operate to any sort of acceptable level.

References

Brewer PG, Riley JP (1965). The automatic determination of nitrate in seawater. Deep-Sea Res. 12: 765-772.

Burkill PH (2002). RRS Charles Darwin cruise 132. Analysing the Microbial Biodiversity of the Indian Ocean - AMBITION. 30 Aug-29 Sep 2001. Marine and Freshwater Microbial Biodiversity Cruise Report No.1, 56pp.

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

Jones RD (1991). An improved fluorescence method for the determination of nanomolar concentrations of ammonium in natural waters. Limnol. and Oceanogr. 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 RFC, Woodward EMS (1983). Optimization of the indophenol blue method for the automated determination of ammonia in estuarine waters. Estuarine Coastal and Shelf Science 17:219-224.

BODC Data Processing Procedures

Data were submitted to BODC in an Excel spreadsheet. Sample metadata were checked against information held in the database and any discrepancy was checked with the data originator. Parameter codes defined in BODC parameter dictionary were assigned to the variables. Data were then loaded into BODC's Research Project Database under an Oracle Relational Database Management System without modification except for the following:

Data Quality Report

Although the quality of the data is not affected by what follows, users should be aware that:


Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2001-09-26
End Date (yyyy-mm-dd) 2001-09-26
Organization Undertaking ActivityPlymouth Marine Laboratory
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierCD132_CTD_CD132_061
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for CD132_CTD_CD132_061

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
141531   20.00        9.90   10.10    9.90 Niskin bottle No problem reported    
141614   20.00       91.90   92.00   91.30 Niskin bottle No problem reported    
141615   20.00       85.00   85.20   84.50 Niskin bottle No problem reported    
141616   20.00       80.10   80.20   79.60 Niskin bottle No problem reported    
141617   20.00       74.90   75.00   74.40 Niskin bottle No problem reported    
141618   20.00       69.90   70.00   69.50 Niskin bottle No problem reported    
141619   20.00       65.00   65.20   64.70 Niskin bottle No problem reported    
141620   20.00       59.90   60.10   59.60 Niskin bottle No problem reported    
141621   20.00       54.80   54.90   54.50 Niskin bottle No problem reported    
141622   20.00       50.00   50.20   49.80 Niskin bottle No problem reported    
141623   20.00       44.90   45.10   44.70 Niskin bottle No problem reported    
141624   20.00       40.00   40.10   39.80 Niskin bottle No problem reported    
141625   20.00       34.70   34.90   34.60 Niskin bottle No problem reported    
141626   20.00       30.70   30.90   30.60 Niskin bottle No problem reported    
141627   20.00       27.50   27.70   27.40 Niskin bottle No problem reported    
141628   20.00       23.70   23.80   23.60 Niskin bottle No problem reported    
141629   20.00       20.60   20.80   20.60 Niskin bottle No problem reported    
141630   20.00       15.00   15.20   15.00 Niskin bottle No problem reported    
141632   20.00        5.20    5.40    5.30 Niskin bottle No problem reported    
141633   20.00         .70     .80     .70 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 - 1655423

Cruise

Cruise Name CD132 (AMBITION)
Departure Date 2001-08-30
Arrival Date 2001-09-29
Principal Scientist(s)Peter H Burkill (Plymouth Marine Laboratory)
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