Metadata Report for BODC Series Reference Number 1332875


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) DISCOVERY 2010
 

Data Identifiers

Originator's Identifier JR20090308_CTD_NUTS_42:JR200_031
BODC Series Reference 1332875
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2009-03-17 14:54
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 60.43120 S ( 60° 25.9' S )
Longitude 44.59310 W ( 44° 35.6' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 5.9 m
Maximum Sensor Depth 993.3 m
Minimum Sensor Height 362.3 m
Maximum Sensor Height 1349.7 m
Sea Floor Depth 1355.6 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
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
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 and silicate seawater concentrations for BAS cruise JR20090308

Originator's data acquisition and analysis

Discrete samples were taken 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.

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.

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

References cited

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.

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
- - concentration standard deviation of nitrate + nitrite per unit volume of the water body (dissolved plus reactive particulate <0.4um phase) SDNZAAD2 µmol L -1 BODC derived from duplicate measurements
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
- - concentration standard deviation of silicate per unit volume of the water body (dissolved plus reactive particulate <0.4um phase) SDSLAAD2 µmol L -1 BODC derived from duplicate measurements

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.

Two sampling events associated with GO-FLO bottle deployments were submitted to BODC without any corresponding depths. At present, these events were omitted from the BODC data processing. Hopefully, these data will be included with this dataset once the sample depths have been established.

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. Duplicate measurements were received for event JR200_238, the average and standard deviation for each sample was determined and loaded accordingly.

Data Quality Report

The data originator highlight's in the cruise report that the due to the age of the nutrient autoanalyser and its various components, the quality of the data collected during this cruise may be somewhat infringed.

A few samples have a sampling depth which is deeper than the established water depth. The samples were collect on events JR200_019, 37, 66, 134, 135, 148 and 191. All sample depths were checked against the CTD bottle files and they are correct, there is no way to establish the correct depth of the water column for these events.


Project Information

DISCOVERY 2010

DISCOVERY 2010 will investigate and describe the response of an ocean ecosystem to climate variability, climate change and commercial exploitation. The programme builds on past studies by BAS on the detailed nature of the South Georgia marine ecosystem and its links with the large-scale physical and biological behaviour of the Southern Ocean.

The aim is to identify, quantify and model key interactions and processes on scales that range from microscopic life forms to higher predators (penguins, albatrosses, seals and whales), and from the local to the circumpolar.

Objectives

Assess the links between the status of local marine food webs and variability and change in the Southern Ocean. Develop a linked set of ecosystem models applying relevant marine physics and biology over scales from the local to that of the entire Southern Ocean.

Relevance to Global Science

Ocean ecosystems play a crucial role in maintaining biodiversity, in depositing carbon into the deep ocean, and as a source of protein for humans. However, fishing and climate change are having significant and often detrimental effects. To predict the future state of ocean ecosystems we must develop computer models capable of simulating biological and physical processes on a range of scales from the local to an entire ocean. Developing such predictive models is crucial to the sustainable management of world fisheries and requires integrated analyses of the way whole ecosystems work. DISCOVERY 2010 aims to take this work forward and at the same time help manage the South Georgia and South Sandwich Islands maritime zone. We will do this through providing information on the state of the ecosystem to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), the international body that manages sustainable fishing in the Southern Ocean.

Delivering the Results

DISCOVERY 2010 will undertake an integrated programme of shipboard and land-based field studies of the marine food web, combined with modelling. We will pay particular attention to critical phases in the life cycles of key species, and to examining interactive effects in food webs. Interacting biological and physical processes will be modelled across a range of spatial scales to significantly improve our representation of the ocean ecosystem, upon which sustainable management and the prediction of future climate change can be based. DISCOVERY 2010 will link to BIOFLAME, ACES, and COMPLEXITY, two international programmes, and to a collaborative programme with the University of East Anglia on the role of the Southern Ocean in the global carbon cycle.

Component Projects


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2009-03-17
End Date (yyyy-mm-dd) 2009-03-17
Organization Undertaking ActivityBritish Antarctic Survey
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierJR20090308_CTD_JR200_031
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for JR20090308_CTD_JR200_031

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
227484 12.00        5.50    6.50    5.90 Niskin bottle No problem reported    
227485 12.00       10.00   11.00   10.40 Niskin bottle No problem reported    
227486 12.00       19.60   20.60   19.90 Niskin bottle No problem reported    
227487 12.00       20.50   21.50   20.80 Niskin bottle No problem reported    
227488 12.00       31.20   32.20   31.40 Niskin bottle No problem reported    
227489 12.00       39.40   40.40   39.50 Niskin bottle No problem reported    
227490 12.00       49.60   50.60   49.60 Niskin bottle No problem reported    
227491 12.00       60.50   61.50   60.40 Niskin bottle No problem reported    
227492 12.00       81.00   82.00   80.70 Niskin bottle No problem reported    
227493 12.00      101.30  102.30  100.80 Niskin bottle No problem reported    
227494 12.00      121.80  122.80  121.10 Niskin bottle No problem reported    
227495 12.00      141.40  142.40  140.50 Niskin bottle No problem reported    
227496 12.00      161.50  162.50  160.40 Niskin bottle No problem reported    
227497 12.00      180.40  181.40  179.10 Niskin bottle No problem reported    
227498 12.00      202.20  203.20  200.70 Niskin bottle No problem reported    
227499 12.00      405.40  406.40  401.70 Niskin bottle No problem reported    
227500 12.00      606.60  607.60  600.50 Niskin bottle No problem reported    
227501 12.00      808.20  809.20  799.50 Niskin bottle No problem reported    
227502 12.00     1004.70 1005.70  993.30 Niskin bottle No problem reported    
682976 12.00   2 1005.00 1006.00  993.00 Niskin bottle No problem reported    
682979 12.00   3 1003.70 1004.70  991.70 Niskin bottle No problem reported    
682982 12.00   4 1005.60 1006.60  993.60 Niskin bottle No problem reported    
682985 12.00   6  808.90  809.90  799.60 Niskin bottle No problem reported    
682988 12.00   7  809.10  810.10  799.80 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 JR20090310 (JR200, JR200A, JR208)
Departure Date 2009-03-10
Arrival Date 2009-04-17
Principal Scientist(s)Rebecca Korb (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