Metadata Report for BODC Series Reference Number 1621912
Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
SeaDataNet Quality Flags
Metadata Summary
Data Description |
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Data Identifiers |
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Time Co-ordinates(UT) |
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Spatial Co-ordinates | |||||||||||||||||||||||||||||
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Parameters |
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Definition of BOTTFLAG | |||||||||||||||||||||||||||||
| BOTTFLAG | Definition |
|---|---|
| 0 | The sampling event occurred without any incident being reported to BODC. |
| 1 | The filter in an in-situ sampling pump physically ruptured during sample resulting in an unquantifiable loss of sampled material. |
| 2 | Analytical 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. |
| 3 | The 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. |
| 4 | During 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. |
| 5 | Water was reported to be escaping from the bottle as the rosette was being recovered. |
| 6 | The bottle seals were observed to be incorrectly seated and the bottle was only part full of water on recovery. |
| 7 | Either 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). |
| 8 | There is reason to doubt the accuracy of the sampling depth associated with the sample. |
| 9 | The bottle air vent had not been closed prior to deployment giving rise to a risk of sample contamination through leakage. |
Definition of Rank |
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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 and Lever Action bottles have a capacity between 1.7 and 30 L. Reversing thermometers may be attached to a spring-loaded disk that rotates through 180° on bottle closure.
CTD samples of nutrients collected on cruise D245 along Extended Ellett Line
Originator's Protocol for Data Acquisition and Analysis
Samples for the analysis of dissolved inorganic nutrients (silcate, nitite and nitrate, and phosphate) were collected from the Niskin bottles after oxygen samples has been taken. The nutrient analysis was performed using a segmented flow 'AAII' type auto-analyser. Further details are in the cruise report, pages 33 to 36 and in Hydes, 1984.
References Cited
Holley, S.E., 1998. Report on the maintenance, precision and accuracy of measurements of dissolved inorganic nutrients and dissolved oxygen over 43 days of measurements on Cruise 230 'FOUREX' (07 Aug - 19 Sep 1997). SOC internal document No. 30, 34 pp.
Hydes, D.J.,1984. A manual of methods for the continuous flow determination of nutrients in seawater. IOSDL Report 177, 40 pp.
Murphy, J. and J.P. Riley, 1954. A modified single solution method for the determination of phosphate in natural waters. Anal. Chem. Acta. 27 p 31-66.
Instrumentation Description
The samples were taken with a CTD frame with 24 position rosette and 24 Niskin bottles. Nutrients were analysed with a Technicon AutoAnalyzer II colorimetric autoanalyser.
BODC Data Processing Procedures
Data received were loaded into the BODC database using established BODC data banking procedures.
The originator's pstar file (sam13786) appears to have data in the wrong columns for bottle (=sampnum) 10 to 15, specifically, values in the nitrate flag column should be in the silicate column, and values in the silicate column should be in the phosphate column. This is a reasonable guess based on the values, and was confirmed with data originator, Penny Holliday. When loading to the BODC database, it was noted that in the originator's pstar file (sam13773) bottle (=sampnum) 10, there was no value for pressure for this bottle, so the data from this bottle were discarded as the depth at which the sample was taken is unknown.
Parameters from the originator's source files were mapped to BODC parameter codes as follows:
| Originator's Parameter | Unit | Description | BODC Parameter Code | BODC Unit | Comments |
|---|---|---|---|---|---|
| no2+3 | µmol/l | Nitrate and nitrate from bottle sample determined by Auto Analyzer | NTRZAATX | Micromoles per litre | n/a |
| sio3 | µmol/l | Silicate from bottle sample determined by Auto Analyzer | SLCAAATX | Micromoles per litre | n/a |
| po4 | µmol/l | Phosphate from bottle sample determined by Auto Analyzer | PHOSAATX | Micromoles per litre | n/a |
Data Quality Report
No report provided by the originator, but information about data quality is included in the cruise report
Problem Report
No problem report.
Project Information
No Project Information held for the Series
Data Activity or Cruise Information
Data Activity
| Start Date (yyyy-mm-dd) | 2000-02-02 |
| End Date (yyyy-mm-dd) | 2000-02-02 |
| Organization Undertaking Activity | Southampton Oceanography Centre (now National Oceanography Centre, Southampton) |
| Country of Organization | United Kingdom |
| Originator's Data Activity Identifier | DI245_CTD_CTD13777 |
| Platform Category | lowered unmanned submersible |
BODC Sample Metadata Report for DI245_CTD_CTD13777
| 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| 875549 | 113.20 | 114.20 | 112.60 | Niskin bottle | No problem reported | |||||
| 875552 | 99.00 | 100.00 | 98.60 | Niskin bottle | No problem reported | |||||
| 875555 | 78.90 | 79.90 | 78.70 | Niskin bottle | No problem reported | |||||
| 875558 | 59.70 | 60.70 | 59.60 | Niskin bottle | No problem reported | |||||
| 875561 | 39.70 | 40.70 | 39.80 | Niskin bottle | No problem reported | |||||
| 875564 | 20.30 | 21.30 | 20.60 | Niskin bottle | No problem reported | |||||
| 875567 | 9.50 | 10.50 | 9.90 | Niskin bottle | No problem reported | |||||
| 875570 | 9.50 | 10.50 | 9.90 | 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 | D245 |
| Departure Date | 2000-01-27 |
| Arrival Date | 2000-02-20 |
| Principal Scientist(s) | Colin R Griffiths (Scottish Association for Marine Science), N Penny Holliday (Southampton Oceanography Centre) |
| 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 |
| B | nominal value |
| Q | value below limit of quantification |
