Metadata Report for BODC Series Reference Number 1617488


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 Mick Whitehouse
Originating Organization British Antarctic Survey
Processing Status banked
Project(s) DYNAMOE
 

Data Identifiers

Originator's Identifier JR20041222_CTD_NUTS_42:JR116_128
BODC Series Reference 1617488
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2004-12-31 14:00
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 55.26700 S ( 55° 16.0' S )
Longitude 38.23600 W ( 38° 14.2' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 8.4 m
Maximum Sensor Depth 123.2 m
Minimum Sensor Height 3575.4 m
Maximum Sensor Height 3690.2 m
Sea Floor Depth 3698.6 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
AMONAAD2 1 Micromoles per litre NH4_0.4umFilt_ColAA Concentration of ammonium {NH4+ CAS 14798-03-9} per unit volume of the water body [dissolved plus reactive particulate <0.4/0.45um phase] by filtration and colorimetric autoanalysis
BOTTFLAG 1 Dimensionless C22_flag Sampling process quality flag (BODC C22)
NTRZAAD2 1 Micromoles per litre NO3+NO2_0.4umFilt_ColAA Concentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate <0.4/0.45um phase] by filtration and colorimetric autoanalysis
PHOSAAD2 1 Micromoles per litre PO4_0.4umFilt_ColAA Concentration of phosphate {PO43- CAS 14265-44-2} per unit volume of the water body [dissolved plus reactive particulate <0.4/0.45um phase] by filtration and colorimetric autoanalysis
SAMPRFNM 1 Dimensionless SampRef Sample reference number
SLCAAAD2 1 Micromoles per litre SiOx_0.4umFilt_ColAA Concentration of silicate {SiO44- CAS 17181-37-2} per unit volume of the water body [dissolved plus reactive particulate <0.4/0.45um phase] by filtration and 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.

Nitrate, nitrite, phosphate, silicate and ammonium seawater concentrations for BAS cruise JR20041222

Originator's data acquisition and analysis

Discrete samples were taken either using a CTD water bottle rosette. Discrete samples were subsampled and passed through a mixed ester membrane (Whatman WME, pore size 0.45 µm; pre-soaked in dilute HCl and rinsed with water). All analyses were conducted using a nutrient autoanalyser made up of Technicon MK II single channel 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 660 nm.

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, 1997 for full details of all instrumentation and analysis involved.

References cited

Folkard A.R., 1978 Automatic analysis of seawater nutrients. Fisheries Technical Report, 46, 23.

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 nutritif 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., 1997. Automated Seawater Nutrient Chemistry. 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 concentration of nitrate + nitrite per unit volume of the water body (dissolved plus reactive particulate <0.4 µm phase) NTRZAAD2 µmol L -1 No unit conversion necessary, units analogous with one another
NH4 mmol m -3 concentration of ammonium per unit volume of the water body (dissolved plus reactive particulate <0.4 µm phase) AMONAAD2 µmol L -1 No unit conversion necessary, units analogous with one another
PO4 mmol m -3 concentration of phosphate per unit volume of the water body (dissolved plus reactive particulate <0.4 µm phase) PHOSAAD2 µmol L -1 No unit conversion necessary, units analogous with one another
Si mmol m -3 concentration of silicate per unit volume of the water body (dissolved plus reactive particulate <0.4 µm phase) SLCAAAD2 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 cruise event log, using the event numbers 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

Dynamics of Ocean Management- DYNAMOE

Introduction

DYNAMOE was created in order to provide data for the global management of finfish communities, squid and krill and avoid future long-term damage from over-fishing. The understanding of how the ocean ecosystem works provides scientists with the tools to predict how human activity and climate changes will affect the Southern Ocean environment and how biological communities will respond. This programme will cover a period from March 2000 to April 2005 and is part of the British Antarctic Survey research programme Antarctic Science in the Global Context.

The research will be concentrated on the Scotia Sea, particularly the food-web and fishery dynamics around South Georgia using the sampling facilities on the RRS James Clark Ross, including vertical profiling for temperature and salinity measurements, sensory and acoustic systems for ocean currents measurements and plankton, fish and squid mapping and nets for biological specimens.

The land-based studies will take place at Bird Island, South Georgia following a year-round study of seabirds and marine mammals which will provide an assessment of breeding performance, growth, diet and foraging.

The programme will integrate interdisciplinary studies in population and food webs modelling, as well as develop satellite-tracking capabilities to link the land-based predator studies to the ship-based ocean analyses.

This programme encompasses two projects:

Scientific Objectives

The main objectives are:

Data Availability

Data sets collected during this project are available to the academic community.


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2004-12-31
End Date (yyyy-mm-dd) 2004-12-31
Organization Undertaking ActivityBritish Antarctic Survey
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierJR20041222_CTD_JR116_128
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for JR20041222_CTD_JR116_128

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
221016   10.00        8.00    9.00    8.40 Niskin bottle No problem reported    
221017   10.00       13.00   14.00   13.40 Niskin bottle No problem reported    
221018   10.00       21.80   22.80   22.10 Niskin bottle No problem reported    
221019   10.00       31.90   32.90   32.10 Niskin bottle No problem reported    
221020   10.00       44.50   45.50   44.60 Niskin bottle No problem reported    
221021   10.00       53.10   54.10   53.10 Niskin bottle No problem reported    
221022   10.00       63.10   64.10   63.00 Niskin bottle No problem reported    
221023   10.00       73.80   74.80   73.60 Niskin bottle No problem reported    
221024   10.00       82.70   83.70   82.40 Niskin bottle No problem reported    
221025   10.00       92.50   93.50   92.10 Niskin bottle No problem reported    
221026   10.00      102.00  103.00  101.50 Niskin bottle No problem reported    
221027   10.00      123.90  124.90  123.20 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 JR20041222 (JR116, JR117, JR118, JR119)
Departure Date 2004-12-22
Arrival Date 2005-01-18
Principal Scientist(s)Peter Ward (British Antarctic Survey)
Ship RRS James Clark Ross

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