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Metadata Report for BODC Series Reference Number 1868823


Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
NameCategories
General Oceanics GO-FLO water sampler  discrete water samplers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Prof Nick Owens
Originating Organization Plymouth Marine Laboratory
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) ARABESQUE
 

Data Identifiers

Originator's Identifier DI212_CTD_CH4X_22:A6/1
BODC Series Reference 1868823
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1994-12-09 02:53
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 10.23278 N ( 10° 14.0' N )
Longitude 65.54501 E ( 65° 32.7' E )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth 11.6 m
Maximum Sensor or Sampling Depth 199.2 m
Minimum Sensor or Sampling Height 4201.5 m
Maximum Sensor or Sampling Height 4389.1 m
Sea Floor Depth 4400.7 m
Sea Floor Depth Source PEVENT
Sensor or Sampling Distribution Unspecified -
Sensor or Sampling Depth Datum Unspecified -
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODERankUnitsTitle
ADEPZZ011MetresDepth (spatial coordinate) relative to water surface in the water body
BOTTFLAG1Not applicableSampling process quality flag (BODC C22)
CH4CGCXX1Nanomoles per litreConcentration of methane {CH4 CAS 74-82-8} per unit volume of the water body [dissolved plus reactive particulate phase] by gas chromatography
CH4SGCXX1PercentSaturation of methane {CH4 CAS 74-82-8} in the water body [dissolved plus reactive particulate phase] by computation from concentration
SAMPRFNM1DimensionlessSample reference number

Definition of BOTTFLAG

BOTTFLAGDefinition
0The sampling event occurred without any incident being reported to BODC.
1The filter in an in-situ sampling pump physically ruptured during sample resulting in an unquantifiable loss of sampled material.
2Analytical evidence (e.g. surface water salinity measured on a sample collected at depth) indicates that the water sample has been contaminated by water from depths other than the depths of sampling.
3The feedback indicator on the deck unit reported that the bottle closure command had failed. General Oceanics deck units used on NERC vessels in the 80s and 90s were renowned for reporting misfires when the bottle had been closed. This flag is also suitable for when a trigger command is mistakenly sent to a bottle that has previously been fired.
4During the sampling deployment the bottle was fired in an order other than incrementing rosette position. Indicative of the potential for errors in the assignment of bottle firing depth, especially with General Oceanics rosettes.
5Water was reported to be escaping from the bottle as the rosette was being recovered.
6The bottle seals were observed to be incorrectly seated and the bottle was only part full of water on recovery.
7Either the bottle was found to contain no sample on recovery or there was no bottle fitted to the rosette position fired (but SBE35 record may exist).
8There is reason to doubt the accuracy of the sampling depth associated with the sample.
9The bottle air vent had not been closed prior to deployment giving rise to a risk of sample contamination through leakage.

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

Methane and Nitrous Oxide as part of the ARABESQUE project

Parameter Code Definitions

CH4DGCDX Dissolved methane nanomoles/litre
Single phase equilibration gas chromatography
CH4SGCDX Dissolved methane saturation (%)
Calculated from methane concentration
DN2OGCTX Dissolved nitrous oxide (N2O) nanomoles/litre
Single phase equilibration gas chromatography
SN2OGCTX Dissolved nitrous oxide saturation (%)
Calculated from nitrous oxide concentration

Originator Codes

22 Prof. N.J.P. Owens Univ. of Newcastle

Originator Protocols

The dissolved seawater concentrations of nitrous oxide and methane (both important greenhouse gases) was determined simultaneously to high precision using a fully automated headspace equilibration gas chromatographic technique.

Samples were collected in 1 litre glass volumetric flasks and allowed to overflow by at least three volumes. Immediately following collection, the samples were stabilised by the addition of 200µl 0.25M aqueous mercuric chloride and the flasks were stoppered and inverted to disperse the HgCl2. Analysis followed immediately; the samples were thermally equilibrated to 25°C in a water bath and then equilibrated with a headspace of known nitrous oxide and methane. The equilibrated gases were dried and passed over a Carbosorb column to remove CO2 before being separated on Porapak Q columns and injected into the carrier gas lines (ultra high purity nitrogen) of two Shimadzu GC 8A gas chromatographs. The first was equipped with a flame ionisation detector (FID) for the analysis of methane; the second with an electron capture detector (ECD) for the measurement of nitrous oxide.

Two high mixing ratio primary standards were used for calibration, containing 10ppmv nitrous oxide, 5.2 ppmv methane and 20ppmv nitrous oxide, 8.5ppmv methane respectively. For routine calibrations, four secondary standards were prepared from these primary standards by pressure dilution (Upstill-Goddard et.al. 1990); estimates for their accuracy are 1.5% for methane and 2% for nitrous oxide. Analytical precisions are better than 0.5% for nitrous oxide and 0.4% for methane.

GO-FLO Bottle

A water sampling bottle featuring close-open-close operation. The bottle opens automatically at approximately 10 metres and flushes until closed. Sampling with these bottles avoids contamination at the surface, internal spring contamination, loss of sample on deck and exchange of water from different depths.

There are several sizes available, from 1.7 to 100 litres and are made of PVC with a depth rating of up to 500 m. These bottles can be attached to a rosette or placed on a cable at selected positions.


Project Information

ARABESQUE

ARABESQUE was a multidisciplinary oceanographic research project focused on the Arabian Sea and Northwest Indian Ocean during the monsoon and intermonsoon season in 1994. Funding for ARABESQUE was provided by the Ministry of Defence/ Defence Research Agency Joint Grant TQ/10/3/2 and Amersham International as well as the Natural Environment Research Council. ARABESQUE was almost entirely field based with extensive physical, chemical and biological measurements made in the Gulf of Oman, the Arabian Sea and the Northwest Indian Ocean. The aim of the project was to study the upper ocean microbial biogeochemistry in the Arabian Sea. Its focus was carbon and nitrogen cycling processes linked to climate change. The project was a UK contribution to the Joint Global Ocean Flux Study (JGOFS) Process Studies of the Arabian Sea. ARABESQUE was organised by Plymouth Marine Laboratory (PML).

Objectives

The detailed scientific objectives of ARABESQUE were to quantify the seasonal influence of the Monsoon winds in the Arabian Sea on:

  • Upwelling of nutrients and the resultant production and fate of phytoplankton, in terms of size-fractionated, new and regenerated production

  • Vertical and on-shelf gradients of heterotrophic, methanogenic and denitrifying bacteria

  • Distribution of chemotaxonomic pigments with links to optical properties of seawater

  • The Dissolved Inorganic and Organic Carbon cycle

  • Air-sea exchange of Sulphur and Nitrogen biogases including dimethyl sulphide, methylamines and methane

  • Sedimentation rates and the fate of organic matter through the oxygen depleted zone

A final objective was to calibrate satellite data on ocean colour so as to map the biogeochemistry of the northwestern Indian Ocean.

Fieldwork

The fieldwork programme consisted of two cruises of RRS Discovery. Cruise 210 (from 27 August to 4 October 1994) was timed to coincide with the South West Monsoon. Cruise 212 (from 16 November to 19 December 1994) took place during the intermonsoon period through to the onset of the North East Monsoon. The fieldwork programme included three repeated sections;

  • One section along the Gulf of Oman

  • A section at 8°N 67°E to 14° 30N 67°E

  • A major section from 8°N 67°E to the coast of Oman

Other one-off sections were also crossed in the area. Sections were covered by underway upper ocean measurements and by a total of 21 sites where CTD/water-bottle stations were taken, 14 of which were repeated.

Data Management

Data management services to the ARABESQUE project were provided by the British Oceanographic Data Centre, funded by the UK Natural Environment Research Council.


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1994-12-09
End Date (yyyy-mm-dd) 1994-12-09
Organization Undertaking ActivityPlymouth Marine Laboratory
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierDI212_CTD_A6/1
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for DI212_CTD_A6/1

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
70031   10.00      201.80  202.70  199.20 General Oceanics GO-FLO water sampler No problem reported    
70032   10.00      145.20  146.50  143.20 General Oceanics GO-FLO water sampler No problem reported    
70033   10.00      122.20  122.90  120.00 General Oceanics GO-FLO water sampler No problem reported    
70034   10.00      102.60  103.50  100.60 General Oceanics GO-FLO water sampler No problem reported    
70035   10.00       82.20   83.80   80.70 General Oceanics GO-FLO water sampler No problem reported    
70036   10.00       62.30   63.50   60.70 General Oceanics GO-FLO water sampler No problem reported    
70037   10.00       54.30   55.40   52.70 General Oceanics GO-FLO water sampler No problem reported    
70038   10.00       42.70   43.50   41.00 General Oceanics GO-FLO water sampler No problem reported    
70039   10.00       32.70   33.70   31.20 General Oceanics GO-FLO water sampler No problem reported    
70040   10.00       22.50   23.70   21.20 General Oceanics GO-FLO water sampler No problem reported    
70041   10.00       12.90   14.00   11.60 General Oceanics GO-FLO water sampler No problem reported    
70042   10.00        8.00    9.20    6.70 General Oceanics GO-FLO water sampler 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.

Related Data Activity activities are detailed in Appendix 1

Cruise

Cruise Name D212
Departure Date 1994-11-16
Arrival Date 1994-12-19
Principal Scientist(s)Peter H Burkill (Plymouth Marine Laboratory)
Ship RRS Discovery

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameARABESQUE Arabian Sea Station 6 (A6)
CategoryOffshore location
Latitude10° 14.00' N
Longitude65° 32.70' E
Water depth below MSL4386.0 m

ARABESQUE - Arabian Sea Station 6 (A6)

Site A6 is one of 20 ARABESQUE fixed stations illustrated in the map below.

BODC image

ARABESQUE fixed stations were visited by 2 cruises, namely: RRS Discovery 210 (D210) - 25 August to 05 October 1994 and RRS Discovery 212 (D212) - 16 November to 19 December 1994. The cruises operated in survey and station mode: station mode consisted of profiling, production and trap stations.

More information is available via the D210 and D212 cruise reports.

Related Fixed Station activities are detailed in Appendix 2


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
Q value below limit of quantification

Appendix 1: DI212_CTD_A6/1

Related series for this Data Activity are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.

Series IdentifierData CategoryStart date/timeStart positionCruise
1300953Water sample data1994-12-09 02:53:0010.23278 N, 65.54501 ERRS Discovery D212
1664334Water sample data1994-12-09 02:53:0010.23278 N, 65.54501 ERRS Discovery D212

Appendix 2: ARABESQUE Arabian Sea Station 6 (A6)

Related series for this Fixed Station are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.

Series IdentifierData CategoryStart date/timeStart positionCruise
965460CTD or STD cast1994-09-18 01:15:0010.224 N, 65.54517 ERRS Discovery D210
1653871Water sample data1994-09-18 01:36:0010.224 N, 65.54514 ERRS Discovery D210
965472CTD or STD cast1994-09-18 02:24:0010.21167 N, 65.55633 ERRS Discovery D210
1851239Water sample data1994-09-18 02:45:0010.2117 N, 65.5563 ERRS Discovery D210
965484CTD or STD cast1994-09-18 04:12:0010.19667 N, 65.566 ERRS Discovery D210
1851240Water sample data1994-09-18 05:21:0010.19666 N, 65.56593 ERRS Discovery D210
967128CTD or STD cast1994-12-09 00:59:0010.34167 N, 65.47717 ERRS Discovery D212
1300977Water sample data1994-12-09 01:17:0010.34161 N, 65.47716 ERRS Discovery D212
967141CTD or STD cast1994-12-09 02:33:0010.23283 N, 65.545 ERRS Discovery D212
1300953Water sample data1994-12-09 02:53:0010.23278 N, 65.54501 ERRS Discovery D212
967153CTD or STD cast1994-12-09 04:26:0010.238 N, 65.54333 ERRS Discovery D212
1300965Water sample data1994-12-09 05:45:0010.23794 N, 65.54341 ERRS Discovery D212
1868835Water sample data1994-12-09 05:45:0010.23794 N, 65.54341 ERRS Discovery D212