Metadata Report for BODC Series Reference Number 1260390


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 Dr Mike Lucas
Originating Organization Southampton Oceanography Centre (now National Oceanography Centre, Southampton)
Processing Status banked
Project(s) Atlantic Meridional Transect Phase2(AMT)
 

Data Identifiers

Originator's Identifier AMT14_CTD_NUTS_220:AMT14_22
BODC Series Reference 1260390
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2004-05-07 05:51
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 28.08857 S ( 28° 5.3' S )
Longitude 25.10203 W ( 25° 6.1' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor Depth 3.7 m
Maximum Sensor Depth 157.7 m
Minimum Sensor Height 4882.0 m
Maximum Sensor Height 5036.0 m
Sea Floor Depth 5039.7 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
AMONNAKA 1 Micromoles per litre NH4nano Concentration (nM sensitivity) of ammonium {NH4+ CAS 14798-03-9} per unit volume of the water body [dissolved plus reactive particulate phase] by nanomolar ammonium fluorometry after Kerouel and Aminot (1997)
BOTTFLAG 1 Dimensionless C22_flag Sampling process quality flag (BODC C22)
FIRSEQID 1 Dimensionless FireSeqNo Bottle firing sequence number
ROSPOSID 1 Dimensionless RosPos Bottle rosette position identifier
SAMPRFNM 1 Dimensionless SampRef Sample reference number
UREAMDTX 1 Micromoles per litre Urea_unfilt_dia Concentration (nM sensitivity) of urea {CAS 57-13-6} per unit volume of the water body [dissolved plus reactive particulate phase] by manual analysis using the diacetylmonoxime method
 

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.

AMT14 Ammonium (CTD and non-toxic supply) and Urea (CTD bottle) samples

Data Acquisition and Analysis

This data originates from analyses on samples collected with CTD rosette bottles from 41 casts for both ammonium and urea. Water samples were collected from a number of depths during the pre-dawn CTD cast using the Sea-Bird CTD rosette system throughout the cruise. Later in the cruise a number of mid-morning casts were sampled. Samples were collected directly from the Niskin bottle tap using a silicon rubber tube into 50 ml centrifuge tubes. Tubes were rinsed three times with the sample water and then sealed with polypropylene caps to minimise air contact. Samples for urea analysis were frozen and stored for analysis after the cruise.

Additional samples were taken from the surface non-toxic seawater supply at 1500h (ship's time) on a daily basis and analysed for ammonium concentrations.

Ammonium determinations were made using the manual method of Holmes et al. (1999), modified for 10ml sample volumes (after Johnson, UEA) and samples were measured on a Turner Designs TD700 fluorometer fitted with the CDOM filter kit.

Urea concentrations were determined using the room temperature manual method of Goeyens et al. (1998) adapted from Mulvenna and Savidge (1992). All samples were read on a Hitachi 810 Spectrophotometer.

References Cited

Goeyens L., Kindermans N., Abu Yusuf M. and Elskens M. 1998. A room temperature procedure for the manual determination of urea in seawater. Est. Coast. Shelf Science, 47, 415-418.

Holmes R.M., Aminot A., Kerouel R., Hooker B.A. and Peterson B.J. 1999. A simple and precise method for measuring ammonium in marine and freshwater ecosystems. Can. J. Fish. Aquat. Sci. 56, 1801-1808.

Johnson M.T. 2004. The air-sea flux of ammonia, PhD Thesis, University of East Anglia, Norwich.

Mulvenna P.F. and Savidge G., 1992. A modified manual method for the determination of urea in seawater using diacetylmonoxime reagent. Est. Coast. Shelf Science, 34, 429-438.

Instrumentation Description

Not relevant to this dataset.

BODC Data Processing Procedures

Data were submitted to BODC in Microsoft Excel spreadsheet format. Sample metadata (Cast, Date, Lat, Lon, Depth) were checked against information held in the database for the CTD casts - there were a couple of minor depth discrepancies which were corrected after referring back to the data originator. Parameter codes defined in BODC parameter dictionary were assigned to the variables. The data were provided nano-mol per litre units which were converted to micro-mol per litre by dividing by 1000. The units were then consistent with those used for the relevant parameters in the BODC database. NB: the data are from nanomolar analysis and the 4th decimal place can be considered to be significant.

Data loaded into BODC's database with only a unit conversion change applied.

A parameter mapping table is provided below;

Originator's Parameter Units Description BODC Parameter Code Units Comments
[NH4] nmol l -1 Concentration (nM sensitivity) of ammonium {NH 4 } per unit volume of the water column [dissolved plus reactive particulate phase] by nanomolar ammonium fluorometry after Kerouel and Aminot (1997) AMONNAKA µmol l -1 n/a
Ambient [Urea] nmol l -1 Concentration (nM sensitivity) of urea per unit volume of the water column [dissolved plus reactive particulate phase] by manual analysis using the diacetylmonoxime method UREAMDTX µmol l -1 n/a

Data Quality Report

BODC were not advised of any specific QC checks carried out by the data orginator.

Problem Report

Not relevant to this dataset.


Project Information

The Atlantic Meridional Transect - Phase 2 (2002-2006)

Who was involved in the project?

The Atlantic Meridional Transect Phase 2 was designed by and implemented by a number of UK research centres and universities. The programme was hosted by Plymouth Marine Laboratory in collaboration with the National Oceanography Centre, Southampton. The universities involved were:

What was the project about?

AMT began in 1995, with scientific aims to assess mesoscale to basin scale phytoplankton processes, the functional interpretation of bio-optical signatures and the seasonal, regional and latitudinal variations in mesozooplankton dynamics. In 2002, when the programme restarted, the scientific aims were broadened to address a suite of cross-disciplinary questions concerning ocean plankton ecology and biogeochemistry and the links to atmospheric processes.

The objectives included the determination of:

The data were collected with the aim of being distributed for use in the development of models to describe the interactions between the global climate system and ocean biogeochemistry.

When was the project active?

The second phase of funding allowed the project to continue for the period 2002 to 2006 and consisted of six research cruises. The first phase of the AMT programme ran from 1995 to 2000.

Brief summary of the project fieldwork/data

The fieldwork on the first three cruises was carried out along transects from the UK to the Falkland Islands in September and from the Falkland Islands to the UK in April. The last three cruises followed a cruise track between the UK and South Africa, only deviating from the traditional transect in the southern hemisphere. During this phase the research cruises sampled further into the centre of the North and South Atlantic Ocean and also along the north-west coast of Africa where upwelled nutrient rich water is known to provide a significant source of climatically important gases.

Who funded the project?

Natural Environment Research Council (NERC)


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2004-05-07
End Date (yyyy-mm-dd) 2004-05-07
Organization Undertaking ActivitySouthampton Oceanography Centre (now National Oceanography Centre, Southampton)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierAMT14_CTD_AMT14_22
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for AMT14_CTD_AMT14_22

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
511914   20.00 19 19   12.50   13.10   12.00 Niskin bottle No problem reported    
511915   20.00 20 20   12.50   13.80   12.30 Niskin bottle No problem reported    
511916   20.00 21 21   11.40   12.50   11.10 Niskin bottle No problem reported    
511917   20.00 22 22   13.00   13.90   12.60 Niskin bottle No problem reported    
511918   20.00 23 23    5.40    6.20    5.00 Niskin bottle No problem reported    
511919   20.00 24 24    3.80    5.20    3.70 Niskin bottle No problem reported    
512063   20.00 1 1  301.70  302.00  298.90 Niskin bottle No problem reported    
512064   20.00 2 2  250.30  251.70  248.40 Niskin bottle No problem reported    
512065   20.00 3 3  198.60  199.30  196.80 Niskin bottle No problem reported    
512066   20.00 4 4  159.40  159.70  157.70 Niskin bottle No problem reported    
512067   20.00 5 5  158.80  159.80  157.40 Niskin bottle No problem reported    
512068   20.00 6 6  156.60  159.10  156.00 Niskin bottle No problem reported    
512069   20.00 7 7  125.10  125.60  123.70 Niskin bottle No problem reported    
512070   20.00 8 8  103.70  105.10  102.90 Niskin bottle No problem reported    
512071   20.00 9 9  104.60  106.20  103.90 Niskin bottle No problem reported    
512072   20.00 10 10  101.60  105.60  102.20 Niskin bottle No problem reported    
512073   20.00 11 11  103.80  105.70  103.30 Niskin bottle No problem reported    
512074   20.00 12 12   82.50   83.30   81.60 Niskin bottle No problem reported    
512075   20.00 13 13   44.60   45.90   44.20 Niskin bottle No problem reported    
512076   20.00 14 14   44.80   45.10   43.90 Niskin bottle No problem reported    
512077   20.00 15 15   44.10   44.40   43.20 Niskin bottle No problem reported    
512078   20.00 16 16   24.40   24.70   23.70 Niskin bottle No problem reported    
512079   20.00 17 17   25.00   25.30   24.30 Niskin bottle No problem reported    
512080   20.00 18 18   23.00   24.10   22.70 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 - 1125907

Cruise

Cruise Name JR20040428 (AMT14, JR101)
Departure Date 2004-04-28
Arrival Date 2004-06-01
Principal Scientist(s)Patrick M Holligan (University of Southampton School of Ocean and Earth Science)
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