Metadata Report for BODC Series Reference Number 1306973


Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
NameCategories
unknown  unknown
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Mr Mick Whitehouse
Originating Organization British Antarctic Survey
Processing Status banked
Project(s) -
 

Data Identifiers

Originator's Identifier JB10_LEG_2_CTD_NUTS_42:JB10_743
BODC Series Reference 1306973
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1990-02-18 13:13
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 53.78300 S ( 53° 47.0' S )
Longitude 38.41800 W ( 38° 25.1' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 23.8 m
Maximum Sensor Depth 241.7 m
Minimum Sensor Height 8.6 m
Maximum Sensor Height 226.5 m
Sea Floor Depth 250.3 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
AMONAAD3 1 Micromoles per litre NH4_GF/CFilt_ColAA Concentration of ammonium {NH4+ CAS 14798-03-9} per unit volume of the water body [dissolved plus reactive particulate
BOTTFLAG 1 Dimensionless C22_flag Sampling process quality flag (BODC C22)
NTRZAAD3 1 Micromoles per litre NO3+NO2_GF/CFilt_ColAA Concentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate
PHOSAAD3 1 Micromoles per litre PO4_GF/CFilt_ColAA Concentration of phosphate {PO43- CAS 14265-44-2} per unit volume of the water body [dissolved plus reactive particulate
SAMPRFNM 1 Dimensionless SampRef Sample reference number
SLCAAAD3 1 Micromoles per litre SiOx_GF/CFilt_ColAA Concentration of silicate {SiO44- CAS 17181-37-2} per unit volume of the water body [dissolved plus reactive particulate
 

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

Nitrate, phosphate, silicate and ammonium seawater concentrations for BAS cruise JB10 Leg 2

Originator's data acquisition and analysis

Discrete samples from vertical profiles were collected using a CTD water bottle rosette. The samples were subsampled and passed through a glass fibre filter (Whatman GF/C, pore size 1.2 µm) by means of a syringe with an in-line luer-locking filtration unit. All analyses were conducted using a nutrient autoanalyser made up of Chemlab colorimeters and Ismatec pumps and custom built reaction manifolds.

Nitrate Determination of nitrate was conducted following the method described by Stainton (1974). Nitrate is reduced to nitrite by passing the sample stream through a transmission tube containing a copper-coated cadmium wire. Nitrite ions diazotise sulphanilamide then couple with N-1-naphthylethylenediamine dihydrochloride to form an azo-dye, the concentration of which is measured by absorbance at 550 nm.

Phosphate Phosphate concentration was determined following a method similar to that described by Tréguer and Le Corre (1975). Orthophosphate ions react with acidified ammonium molybdate in the presence of antimony to form phosphomolbdic acid. This is reduced by ascorbic acid to a 'molydenum blue' complex (Riley and Skirrow, 1975) the concentration of which is measured by absorbance at 630nm.

Silicate The concentration of silicate in seawater was determined using a method based on an industrial method by Technicon (1976). Silicate ions react with ammonium molybdate in acidic conditions producing silicomolybdic acid. This is reduced to a 'molybdenum blue' complex by ascorbic acid (Riley and Skirrow, 1975) and its concentration is measured by absorbance at 680 nm. Interference from phosphates at normal concentrations is eliminated by the introduction of oxalic acid into the sample stream prior to the addition of ascorbic acid.

Ammonium Ammonia is determined using a variant of the Berthelot reaction. Sodium dichloroisocyanurate is used as a hypochlorite donor (Krom, 1984) and catalysis is performed by potassium ferrocyanide. After reagent additions, the reaction stream is heated to 40°C and formation of 'indophenol blue' is promoted under longwave UV radiation (365 nm). Concentration is measured by absorbance at 630 nm.

See Whitehouse and Woodley, 1987 for full details of all instrumentation and analysis involved.

References cited

Krom M.D., 1984 Spectrophotometric determination of ammonia. A study of a modified Berthelot reaction using salicylate and dichloroisocyanurate. The Analyst, 105, 305-316.

Riley J.P. and Skirrow G., 1975. Chemical Oceanography, 3, (2nd Edition), London, Academic Press.

Stainton M.P., 1974. Simple, efficient reduction column for use in the automated determination of nitrate in water. Analytical Chemistry, 46, 1616.

Technicon Instruments Corporation, 1976. Silicates in water and wastewater. Technicon industrial method No 105-71.

Tréguer P. and Le Corre P., 1975. Manuel d'analyse des sels nutritifs dans l'eau de mer (Utilisation de l'AutoAnalyser II, Technicon, 2nd edition). Report laboratoire d'oceanologie chimique, Université de Bretagne Occidentale, Brest, France.

Whitehouse M.J. and Woodley V.R., 1987. Automated Seawater Nutrient Analysis. British Antarctic Survey, Cambridge.

BODC Data Processing Procedures

Data were received by BODC in spreadsheet format with the nutrient data from various BAS cruises in labeled worksheets (BAS_nutrient_data_1981-2009.xls). The following metadata fields were also included with the data: cruise ID, date, latitude, longitude, event number and pressure.

Parameter codes defined in the BODC parameter dictionary were mapped to the variables as follows:

Originator's Parameter Units Description BODC Parameter Code Units Comments
NO3 mmol m -3 colorimetric autoanalysis of nitrate + nitrite (<GF/C) NTRZAAD3 µmol L -1 No unit conversion necessary, units analogous with one another
NH4 mmol m -3 colorimetric autoanalysis of ammonium (<GF/C) AMONAAD3 µmol L -1 No unit conversion necessary, units analogous with one another
PO4 mmol m -3 colorimetric autoanalysis of phosphate (<GF/C) PHOSAAD3 µmol L -1 No unit conversion necessary, units analogous with one another
Si mmol m -3 colorimetric autoanalysis of silicate (<GF/C) SLCAAAD3 µmol L -1 No unit conversion necessary, units analogous with one another

Nutrient data were received with no associated time for the sampling event. It was therefore deemed necessary to acquire times from the CTD cast data inventory for this cruise already stored at BODC. Positional data from the nutrient data file and positional data from the CTD cast metadata were used to map the correct times to the nutrient sampling events.

The depth of the water column at each sampling event has been assigned using GMT and GEBCO data .

The data were banked according to BODC standard procedures for sample data. Data were banked as received, with no averaging or other modifications applied.

Data Quality Report

There are no data quality issues to report.


Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1990-02-18
End Date (yyyy-mm-dd) 1990-02-18
Organization Undertaking ActivityBritish Antarctic Survey
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierJB10 LEG 2_CTD_JB10_743
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for JB10 LEG 2_CTD_JB10_743

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
212275         23.50   24.50   23.80 unknown No problem reported    
212276        243.50  244.50  241.70 unknown 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 JB10 Leg 2
Departure Date 1990-01-31
Arrival Date 1990-02-22
Principal Scientist(s)Jonathan L Watkins (British Antarctic Survey), Julian Priddle (British Antarctic Survey)
Ship RRS John Biscoe

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