Metadata Report for BODC Series Reference Number 1788939


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 Carol Robinson
Originating Organization Plymouth Marine Laboratory
Processing Status banked
Project(s) Atlantic Meridional Transect (AMT)
 

Data Identifiers

Originator's Identifier AMT6_CTD_DOXY_57:CTD33
BODC Series Reference 1788939
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1998-06-01 09:27
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 3.07317 N ( 3° 4.4' N )
Longitude 12.77174 W ( 12° 46.3' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor Depth 2.3 m
Maximum Sensor Depth 9.1 m
Minimum Sensor Height 4312.3 m
Maximum Sensor Height 4319.1 m
Sea Floor Depth 4321.4 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)
DOXYWITX 1 Micromoles per litre WC_dissO2_Winkler Concentration of oxygen {O2 CAS 7782-44-7} per unit volume of the water body [dissolved plus reactive particulate phase] by Winkler titration
OXYSBW01 1 Percent BKWink Saturation of oxygen {O2 CAS 7782-44-7} in the water body [dissolved plus reactive particulate phase] by Winkler titration and computation from concentration using Benson and Krause algorithm
SAMPRFNM 1 Dimensionless SampRef Sample reference number
 

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.

AMT6 Oxygen concentrations from CTD bottle samples

Originator's Protocol for Data Acquisition and Analysis

This data originates from analyses on samples collected from 27 stations during the cruise. Samples were taken from up to 12 bottles fired during the morning casts.

Measurements of dissolved oxygen were made with an automated Winkler titration system based on that described in Williams and Jenkinson (1982). Oxygen saturation was calculated using the equations for the solubility of oxygen in seawater of Benson and Krause (1984).

References Cited

Benson B.B. and Krause D.Jr., 1984. The concentration and isotopic fractionation of oxygen dissolved in freshwater and seawater in equilibrium with the atmosphere. Limnology and Oceanography, 29, 620-632.

Williams P.J.Leb. and Jenkinson N.W., 1982. A transportable micro processor controlled precise Winkler titration suitable for field station and shipboard use. Limnology and Oceanography, 27, 576-584.

Instrumentation Description

Not applicable for this data set.

BODC Data Processing Procedures

Data were submitted with the AMT6 Dissolved Inorganic Carbon (DIC) dataset in an Excel spreadsheet archived under BODC's accession number PML030011. Sample metadata (CTD cast, date, latitude, longitude and depth) were checked against information held in the database. There were no discrepancies.

The concentration data were provided in millimoles per cubic metre and the saturation data in percentage saturation. These units for the concentration data were equivalent to the BODC parameter code units (micro-moles per litre) and the saturation data units matched the BODC parameter code unit so no unit conversions were applied.

The data were reformatted and loaded in BODC's samples database under Oracle Relational Database Management System. Data were marked up with BODC parameter codes and loaded into the database. Individual samples were matched by depth for each cast.

A parameter mapping table is provided below;

Originator's Parameter Units Description BODC Parameter Code Units Comments
Oxygen concentration mmol m -3 Concentration of oxygen {O2} per unit volume of the water body [dissolved phase] by Winkler titration DOXYWITX µmol l -1 n/a
Oxygen saturation %age satn Saturation of oxygen {O2} in the water body [dissolved phase] by Winkler titration and computation from concentration using Benson and Krause algorithm OXYSBW01 Percent n/a

Data Quality Report

The data originator highlighted two samples where the oxygen data were suspect - these have been flagged 'L' in the database. The data originator also suspected H 2 S interference during A6-12 (CTD12). These data have not been flagged.

Problem Report

Not relevant to this data set.


Project Information

The Atlantic Meridional Transect (AMT) - Phase 1 (1995-2000)

Who was involved in the project?

The Atlantic Meridional Transect (AMT) programme was designed by and implemented as a collaboration between Plymouth Marine Laboratory (PML) and Southampton Oceanography Centre (SOC). The programme was hosted by Plymouth Marine Laboratory and involved additional researchers from UK and international universities throughout its duration.

What was the project about?

When AMT began in 1995 the programme provided a platform for international scientific collaboration, including the calibration and validation of SeaWiFs measurements and products. The programme provided an exceptional opportunity for nationally and internationally driven collaborative research and provided a platform for excellent multi-disciplinary oceanographic research. As an in situ observation system, the data collected by the AMT consortium informed on changes in biodiversity and function of the Atlantic ecosystem during this period of rapid change to our climate and biosphere.

The scientific aims were to assess:

When was the project active?

The first phase of the AMT programme ran from 1995 to 2000 and consisted of a total of 12 cruises. A second phase of funding allowed the project to continue for the period 2002 to 2006 with a further 6 cruises.

Brief summary of the project fieldwork/data

The AMT programme undertook biological, chemical and physical oceanographic research during the annual return passage of the RRS James Clark Ross between the UK and the Falkland Islands or the RRS Discovery between the UK and Cape Town, a distance of up to 13,500 km. This transect crossed a range of ecosystems from sub-polar to tropical and from euphotic shelf seas and upwelling systems to oligotrophic mid-ocean gyres. The transect route was covered north-south in September/October and south-north in April/May of each year.

The measurements of hydrographic and bio-optical properties, plankton community structure and primary production completed on the first 12 transects (1995-2000) represent the most coherent set of repeated biogeochemical observations over ocean basin scales. This unique dataset has led to several important discoveries concerning the identification of oceanic provinces, validation of ocean colour algorithms, distributions of picoplankton, identifying new regional sinks of pCO2 and variability in rates of primary production and respiration.

Who funded the project?

The programme was funded by the Natural Environment Research Council (NERC) and further support was received from the National Aeronautics and Space Administration (NASA) with equipment and funding from the Sea-viewing Wild Field-of-view Sensor (SeaWiFS) project.


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1998-06-01
End Date (yyyy-mm-dd) 1998-06-01
Organization Undertaking ActivityPlymouth Marine Laboratory
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierAMT6_CTD_CTD33
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for AMT6_CTD_CTD33

Sample reference number 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
501283           7.40       9.40       9.10 30-litre Niskin No problem reported    
501455             .50       2.50       2.30 30-litre Niskin 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 - 1094833

Cruise

Cruise Name JR19980514 (AMT6, JR32)
Departure Date 1998-05-14
Arrival Date 1998-06-16
Principal Scientist(s)James Aiken (Plymouth Marine Laboratory)
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