Metadata Report for BODC Series Reference Number 1340469


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 Ms Amanda Beesley
Originating Organization Plymouth Marine Laboratory
Processing Status banked
Project(s) Oceans 2025 Theme 10 SO1:AMT
 

Data Identifiers

Originator's Identifier D371_CTD_NUTS_861:CTD009
BODC Series Reference 1340469
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2011-10-04 04:54
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 41.79503 N ( 41° 47.7' N )
Longitude 21.17866 W ( 21° 10.7' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 2.5 m
Maximum Sensor Depth 200.8 m
Minimum Sensor Height 3615.9 m
Maximum Sensor Height 3814.2 m
Sea Floor Depth 3816.7 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)
FIRSEQID 1 Dimensionless FireSeqNo Bottle firing sequence number
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
ROSPOSID 1 Dimensionless RosPos Bottle rosette position identifier
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.

AMT21 (D371) Micro-molar nutrient measurements from CTD bottle samples

Originator's Protocol for Data Acquisition and Analysis

Water samples were taken from the Sea-Bird CTD rosette system. They were sub-sampled into acid-clean 60 ml HDPE (nalgene) sample bottles. Analysis for nutrients was completed within 1-2 hours of sampling in all cases. Clean handling techniques were employed to avoid contamination of the samples.

The main nutrient analyser was a 5-channel Bran and Luebbe AAIII segmented flow autoanalyser. The analytical chemical methodologies used were according to Brewer and Riley (1965) for nitrate, Grasshoff (1976) for nitrite and Kirkwood (1989) for phosphate and silicate.

References Cited

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

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

Kirkwood D.S., 1989. Simultaneous determination of selected nutrients in seawater. ICES CM1989/C:29, 12pp.

Instrumentation Description

5-channel Bran and Luebbe AAIII segmented flow autoanalyser

BODC Data Processing Procedures

Data were submitted to BODC in Microsoft Excel spreadsheet format and saved to the BODC archive with reference PML130010. Sample metadata provided (Cast number, niskin bottle number and sample depth) were checked against information held in the database. There were a few minor depth discrepancies that were resolved through correspondence with the originator.

No unit conversions were necessary as the units provided matched the units for the parameter codes in the BODC Parameter Dictionary. The dataset was loaded to the database following BODC protocols.

A parameter mapping table is provided below;

Originator's Parameter Units Description BODC Parameter Code Units Comments
Nitrate+Nitrite µmol l -1 Concentration of nitrate+nitrite {NO 3 +NO 2 } per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis NTRZAATX µmol l -1 -
Nitrite µmol l -1 Concentration of nitrite {NO 2 } per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis NTRIAATX µmol l -1 -
Phosphate µmol l -1 Concentration of phosphate {PO 4 } per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis PHOSAATX µmol l -1 -
Silicate µmol l -1 Concentration of silicate {SiO 4 } per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis SLCAAATX µmol l -1 -

Data Quality Report

Data provided were quality checked by the originator and flagged accordingly. The nutrients supplied from cast CTD002 were flagged as the originator suspected the sample order had become mixed up and there was no way to confirm what should be the correct order.

Measurement precision information from data originators: quantities flagged as below detection by the originators have been given the value of the limit of detection and flagged appropriately in the BODC database.

Problem Report

Not applicable for this dataset.


Project Information

Oceans 2025 Theme 10, Sustained Observation Activity 1: The Atlantic Meridional Transect (AMT)

The Atlantic Meridional Transect has been operational since 1995 and through the Oceans 2025 programme secures funding for a further five cruises during the period 2007-2012. The AMT programme began in 1995 utilising the passage of the RRS James Clark Ross between the UK and the Falkland Islands southwards in September and northwards in April each year. Prior to Oceans 2025 the AMT programme has completed 18 cruises following this transect in the Atlantic Ocean. This sustained observing system aims to provide basin-scale understanding of the distribution of planktonic communities, their nutrient turnover and biogenic export in the context of hydrographic and biogeochemical provinces of the North and South Atlantic Oceans.

The Atlantic Meridional Transect Programme is an open ocean in situ observing system that will:

The specific objectives are:

The measurements taken and experiments carried out on the AMT cruises will be closely linked to Themes 2 and 5. The planned cruise track also allows for the AMT data to be used in providing spatial context to the Sustained Observation Activities at the Porcupine Abyssal Plain Ocean Observatory (SO2) and the Western Channel Observatory (SO10).

More detailed information on this Work Package is available at pages 6 - 9 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10

Weblink: http://www.oceans2025.org/


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2011-10-04
End Date (yyyy-mm-dd) 2011-10-04
Organization Undertaking ActivityPlymouth Marine Laboratory
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierD371_CTD_CTD009
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for D371_CTD_CTD009

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
616970   20.00 1 1  304.30  304.80  301.20 Niskin bottle Bottle misfire    
616973   20.00 2 2  203.10  203.40  200.80 Niskin bottle No problem reported    
616976   20.00 3 3  152.70  153.20  151.00 Niskin bottle No problem reported    
616979   20.00 4 4  112.70  113.10  111.30 Niskin bottle No problem reported    
616982   20.00 5 5   92.10   92.80   91.00 Niskin bottle No problem reported    
616985   20.00 6 6   82.10   82.80   81.10 Niskin bottle No problem reported    
616988   20.00 7 7   66.90   67.20   65.80 Niskin bottle No problem reported    
616991   20.00 8 8   67.20   67.60   66.10 Niskin bottle No problem reported    
616994   20.00 9 9   64.70   65.10   63.70 Niskin bottle No problem reported    
616997   20.00 10 10   64.70   65.30   63.80 Niskin bottle No problem reported    
617486   20.00 11 11   65.00   65.40   64.00 Niskin bottle No problem reported    
617489   20.00 12 12   51.60   52.20   50.80 Niskin bottle No problem reported    
617492   20.00 13 13   39.60   40.60   39.10 Niskin bottle No problem reported    
617495   20.00 14 14   39.90   40.30   39.10 Niskin bottle No problem reported    
617498   20.00 15 15   30.10   30.30   29.20 Niskin bottle No problem reported    
617501   20.00 16 16   29.80   30.40   29.10 Niskin bottle No problem reported    
617504   20.00 17 17   21.30   21.90   20.70 Niskin bottle No problem reported    
617507   20.00 18 18   17.70   18.30   17.10 Niskin bottle No problem reported    
617510   20.00 19 19   17.50   18.30   17.00 Niskin bottle No problem reported    
617513   20.00 20 20   10.10   10.90    9.70 Niskin bottle No problem reported    
617516   20.00 21 21   10.10   10.80    9.70 Niskin bottle No problem reported    
617519   20.00 22 22    2.60    3.90    2.50 Niskin bottle No problem reported    
617522   20.00 23 23    3.00    3.70    2.60 Niskin bottle No problem reported    
617525   20.00 24 24    3.30    3.90    2.90 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 D371 (AMT21)
Departure Date 2011-09-29
Arrival Date 2011-11-13
Principal Scientist(s)Glen A Tarran (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