Metadata Report for BODC Series Reference Number 1350440
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.
Extended Ellett Line Inorganic Nutrient Data for RRS Discovery cruise D312
Originator's Data Acquisition and Analysis
Inorganic nutrients were measured on every bottle from every CTD cast following Sanders and Jickells (2000) using a Skalar San Plus autoanalyser equipped equipped with an all glass phosphate line. All data was processed in flow access version 1.04.4. In total 634 niskin bottle were analysed. Samples were drawn directly from niskin bottles into 25 ml sterilin polystyrene coulter counter vials, refrigerated in the dark at 4°C and analysed within 24 hours. Overall seventeen runs were carried out.
The instrument did not perform well on this trip despite the usual precautions being taken (washing the lines with 10 % Decon (N, Si) or Sodium Hydroxide (P), changing the tubes). Despite the various problems encountered all samples were analysed satisfactorily with the exception of phosphate from station 152.
BODC processing
The data were received in 64 pstar files which were loaded into the BODC database using established BODC data banking procedures without any changes.
The mapping between the originator's channels and BODC parameter codes is detailed in the table below.
| Originator's Parameter | Unit | Description | BODC Parameter Code | BODC Unit | Comments |
|---|---|---|---|---|---|
| NO3+NO2 | Micromoles per litre | Concentration of Nitrate + Nitrite {NO3+NO2} | NTRZAATX | Micromoles per litre | n/a |
| PO4 | Micromoles per litre | Concentration of Phosphate {PO4} | PHOSAATX | Micromoles per litre | n/a |
| SiO4 | Micromoles per litre | Concentration of Silicate | SLCAAATX | Micromoles per litre | n/a |
Data Quality Report
For a detailed QC analysis please see (Cruise Report) page 106.
Project Information
No Project Information held for the Series
Data Activity or Cruise Information
Data Activity
| Start Date (yyyy-mm-dd) | 2006-10-26 |
| End Date (yyyy-mm-dd) | 2006-10-26 |
| Organization Undertaking Activity | National Oceanography Centre, Southampton |
| Country of Organization | United Kingdom |
| Originator's Data Activity Identifier | D312_CTD_16167 |
| Platform Category | lowered unmanned submersible |
BODC Sample Metadata Report for D312_CTD_16167
| 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| 185746 | 10.00 | 1 | 122.30 | 123.30 | 121.60 | Niskin bottle | No problem reported | |||
| 185747 | 10.00 | 2 | 102.30 | 103.30 | 101.80 | Niskin bottle | No problem reported | |||
| 185748 | 10.00 | 3 | 51.80 | 52.80 | 51.80 | Niskin bottle | No problem reported | |||
| 185749 | 10.00 | 4 | 11.30 | 12.30 | 11.70 | 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.
Cruise
| Cruise Name | D312 |
| Departure Date | 2006-10-11 |
| Arrival Date | 2006-10-31 |
| Principal Scientist(s) | John T Allen (National Oceanography Centre, Southampton) |
| 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 |
