Metadata Report for BODC Series Reference Number 1251847
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.
Micro- and nanomolar-sensitivity nutrient analysis on cruise RRS Discovery DI241
Document History
Converted from CDROM documentation
Data Originator
Malcolm Woodward
Content of data series
| Parameter | Code | Unit | Samples |
|---|---|---|---|
| Dissolved ammonia (unfiltered)-nanomolar analyser | AMONNATX | µmol l-1 | 314 |
| Dissolved nitrite (unfiltered) | NTRIAATX | µmol l-1 | 369 |
| Dissolved nitrate + nitrite (unfiltered) - Technicon analyser | NTRZAATX | µmol l-1 | 362 |
| Dissolved nitrate + nitrite (unfiltered) - nanomolar NOx analyser | NTRZNNTX | µmol l-1 | 183 |
| Dissolved phosphate (unfiltered) | PHOSAATX | µmol l-1 | 369 |
| Dissolved silicate (unfiltered) | SLCAAATX | µmol l-1 | 369 |
Sampling strategy and methodology
Water samples were subsampled directly from the CTD bottles into clean Nalgene bottles. Analysis was carried out on board ship, and completed within 2 hours of sampling in every case.
Inorganic nutrient concentrations were determined using a 5-channel Technicon AAII, segmented flow analyser. The methodologies used for each nutrient followed those of Brewer and Riley (1965) for nitrate, Grasshoff (1976) for nitrite, Kirkwood (1989) for phosphate and silicate, and Mantoura and Woodward (1983) for ammonia.
As ammonia concentrations dropped below the detection limits for the colorimetric system, a nanomolar Ammonia analysis system (adapted from Jones, 1991) was used. Similarly, samples which had nitrate + nitrite concentrations below the detection limit of the Technicon method were analysed using the nanomolar chemiluminescence system (Garside, 1982). The two different methods used for analysis of nitrate + nitrite are indicated in the parameter codes.
References
Brewer, P.G. and Riley, J.P., 1965. The automatic determination of nitrate in seawater. Deep-Sea Research, 12, 765-772.
Garside, C., 1982. A chemiluminescent technique for the determination of nanomolar concentrations of nitrate and nitrite in seawater. Marine Chemistry, 11, 159-167.
Grasshoff, K., 1976. Methods of seawater analysis. Verlag Chemie, Weiheim. 317pp
Jones, R.D., 1991. An improved fluorescence method for the determination of nanomolar concentrations of ammonium in natural waters. Limnology and Oceanography, 36, 814-819.
Kirkwood, D., 1989. Simultaneous determination of selected nutrients in sea water. International Council for the Exploration of the Sea (ICES), CM 1989/C:29.
Mantoura, R.F.C. and Woodward, E.M.S., 1983. Optimisation of the indophenol blue method for the automated determination of ammonia in estuarine waters. Estuarine, Coastal and Shelf Science, 17, 219-224.
Project Information
No Project Information held for the Series
Data Activity or Cruise Information
Data Activity
| Start Date (yyyy-mm-dd) | 1999-06-26 |
| End Date (yyyy-mm-dd) | 1999-06-26 |
| Organization Undertaking Activity | Plymouth Marine Laboratory |
| Country of Organization | United Kingdom |
| Originator's Data Activity Identifier | DI241_CTD_CTD60 |
| Platform Category | lowered unmanned submersible |
BODC Sample Metadata Report for DI241_CTD_CTD60
| 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| 108575 | 30.00 | 76.80 | 78.00 | 75.80 | Niskin bottle | No problem reported | ||||
| 108576 | 30.00 | 50.60 | 51.70 | 49.80 | Niskin bottle | No problem reported | ||||
| 108577 | 30.00 | 40.30 | 41.80 | 39.80 | Niskin bottle | No problem reported | ||||
| 108578 | 30.00 | 25.20 | 26.60 | 24.80 | Niskin bottle | No problem reported | ||||
| 108579 | 30.00 | 19.70 | 20.90 | 19.20 | Niskin bottle | No problem reported | ||||
| 108580 | 30.00 | 14.80 | 16.00 | 14.40 | Niskin bottle | No problem reported | ||||
| 108581 | 30.00 | 9.90 | 11.10 | 9.50 | Niskin bottle | No problem reported | ||||
| 108582 | 30.00 | 4.70 | 5.70 | 4.30 | Niskin bottle | No problem reported | ||||
| 108583 | 30.00 | 2.10 | 2.90 | 1.60 | Niskin bottle | No problem reported | ||||
| 108704 | 30.00 | 101.40 | 102.40 | 100.00 | Niskin bottle | No problem reported | ||||
| 108705 | 30.00 | 29.70 | 31.20 | 29.30 | Niskin bottle | No problem reported | ||||
| 111447 | 30.00 | 23.50 | 24.50 | 22.90 | 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 | D241 |
| Departure Date | 1999-06-04 |
| Arrival Date | 1999-07-01 |
| Principal Scientist(s) | Peter H Burkill (Plymouth Marine Laboratory) |
| 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 |
