Metadata Report for BODC Series Reference Number 1353204
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
A caution flag has been applied to this series in order to alert users that measurements made during this fieldwork activity may have been affected by the artificial perturbation of the natural environment. An in-situ perturbation experiment (e.g. iron enrichment, nutrient addition, addition of surfactant) is a deliberate large-scale change to one or more environmental factors in order to study its effect on biological or biogeochemical properties of interest. They would typically involve the use of an inert and non-toxic tracer such as SF6 to mark the area treated; sampling would then typically take place using a combination of spatial surveys and lagrangian sampling mode. Whether the sampling station is "IN" or "OUT" of the patch is based on the detectable presence of tracer in the samples. Users are therefore advise to use data from these fieldwork activities with caution.
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.
CD156 Nutrient (micro- and nano-molar) measurements from CTD bottle and surface underway samples
Originator's Protocol for Data Acquisition and Analysis
The RRS Charles Darwin CD156 cruise departed on the 26 April 2004 from Santa Cruz de Tenerife, Spain and returned on the 23 May 2004. The cruise set out to test the hypothesis that: The supply of, and the interaction between iron and phosphorus control biological activity and fluxes in the subtropical North Atlantic.
Sample collection
Water samples were taken from the Sea-Bird CTD rosette system on most casts, these were sub sampled into acid clean 60 mls HDPE (nalgene) sample bottles and analysis for the nutrient samples was in most cases complete within 3-4 hours of sampling. Clean handling techniques were employed to avoid any contamination of the samples, particularly for the nanomolar nutrients. No samples were stored.
Samples were also gathered for nano-molar phosphate analysis using the ship's non-toxic water supply.
Sample analysis
The main nutrient analyser was a 5 channel Bran and Luebbe AAIII, segmented flow autoanalyser. The samples were analysed for nitrate (Brewer and Riley, 1965), for nitrite (Grasshoff, 1976) for phosphate and silicate (Kirkwood, 1989).
Nanomolar ammonium concentrations were obtained with a fluorescent analysis technique following ammonia gas diffusion out of the samples, passing across a hydrophobic Teflon membrane due to differential pH chemistry (adapted from Jones, 1991).
Nanomolar nitrate+nitrite, nitrite and phosphate concentrations were obtained on some samples using a 3-channel nanomolar analyser. This method combines sensitive segmented flow colorimetric analytical techniques with a Liquid Waveguide Capillary Cell (LWCC).
BODC Data Processing Procedures
Discrete nutrient samples were provided to BODC in Excel format. BODC extracted the data and merged with information from the associated Sea-Bird .btl files (also provided). These data were loaded to BODC's ocean database under the ORACLE Relational Database Management System. Data that were considered unrealistic were flagged suspect.
The detection limits for CTD nutrient micro-molar were as follows:
- nitrate+nitrite <0.03 µmol l-1
- nitrite <0.02 µmol l-1
- phosphate <0.03 µmol l-1
The detection limits for CTD nutrient nano-molar were as follows:
- nitrate+nitrite <0.001 µmol l-1
- nitrite <0.0004 µmol l-1
- phosphate <0.001 µmol l-1
Data from the nanomolar ammonium and LWCC systems were submitted in units of nmol/l. Nano-molar data were divided by 1000 to convert the units to µmol/l for storage in the database.Users should be aware that these LWCC measurements are valid to the fourth decimal place.
Content of data series
The Originator's variables were mapped to appropriate BODC parameter codes as follows:
| Originator's Parameter | Units | Description | BODC Parameter Code | Units | Comments |
|---|---|---|---|---|---|
| Ammonium (nano-molar system) | nmol l-1 | Concentration (nM sensitivity) of ammonium {NH4} per unit volume of the water body [dissolved plus reactive particulate phase] by nanomolar ammonium system after Jones (1991) | AMONNATX | µmol l-1 | nmol l-1 converted to µmol l-1 (conversion used * 1/1000) |
| Nitrate+Nitrite (AAIII) | µmol l-1 | Concentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis | NTRZAATX | µmol l-1 | - |
| Nitrate+Nitrite (LWCC nano-molar system) | nmol l-1 | Concentration (nM sensitivity) of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis with liquid waveguide capilliary cell | NTRZLWTX | µmol l-1 | nmol l-1 converted to µmol l-1 (conversion used * 1/1000) |
| Nitrite (AAIII) | µmol l-1 | Concentration of nitrite {NO2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis | NTRIAATX | µmol l-1 | - |
| Nitrite (LWCC nano-molar system) | nmol l-1 | Concentration (nM sensitivity) of nitrite {NO2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis with liquid waveguide capilliary cell | NTRILWTX | µmol l-1 | nmol l-1 converted to µmol l-1 (conversion used * 1/1000) |
| Phosphate (AAIII) | µmol l-1 | Concentration of phosphate {PO4} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis | PHOSAATX | µmol l-1 | - |
| Phosphate (LWCC nano-molar system) | nmol l-1 | Concentration (nM sensitivity) of phosphate {PO4} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis with liquid waveguide capilliary cell | PHOSLWTX | µmol l-1 | nmol l-1 converted to µmol l-1 (conversion used * 1/1000) |
| Silicate (AAIII) | µmol l-1 | Concentration of silicate {SiO4} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis | SLCAAATX | µmol l-1 | - |
| Underway Phosphate (LWCC nano-molar system) | µmol l-1 | Concentration (nM sensitivity) of phosphate {PO4} per unit volume of the water body [dissolved plus reactive particulate <0.4/0.45um phase] by filtration and colorimetric autoanalysis with liquid waveguide capilliary cell | PHOS04LW | µmol l-1 | nmol l-1 converted to µmol l-1 (conversion used * 1/1000) |
Quality Report
The cruise report implied micro-molar nutrient data were collected at the following CTD casts but were not supplied to BODC: 8, 10, 12, 35, 92 and 93. The cruise report also suggests nano-molar ammonium data were collected at CTD cast 50 but no data were supplied to BODC. CTD nanomolar nutrient and ammonium data were supplied at CTD cast 7 but not mentioned in the cruise report.
CTD casts 89-93 have been flagged as suspicious by the Originator due to significant phosphate and iron contamination.
In some cases, the CTD nanomolar nutrient data values were off scale. These have been recorded to the absent data value and flagged with an N flag.
CTD cast 69 had duplicate niskin numbers at depths 160 m and 180 m, with both linked to niskin 8. By checking the firing depths, the bottle fired at depth 160 m has been updated to niskin 9.
Some discrepancies were found in the Originators metadata in the Underway Phosphate dataset. Following correspondance with the Originator, a revised dataset was supplied for loading to the ORACLE Relational Database Management System.
References Cited
Brewer P.G. and Riley J.P., 1965. The automatic determination of nitrate in sea water. Deep-Sea Research, 12, 765-772.
Grasshoff K., 1976. Methods of seawater analysis. Verlag Chemie, Weiheim: 317 pp.
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.S., 1989. Simultaneous determination of selected nutrients in seawater. ICES CM1989/C:29, 12pp.
Project Information
FeeP - Phosphate and Iron Addition Experiment
Who funded the programme?
The Natural Environment Research Council (NERC).
Who was involved in the programme?
The programme was a collaboration lead by Plymouth Marine Laboratory (PML) and involved scientists from the National Institute of Water and Atmospheric Research, New Zealand, Laboratoire Arago, France and the University of East Anglia.
What was the programme about?
The programme was a two ship exercise using RRS Charles Darwin and RV Pseidon to investigate the hypothesis that:
"The supply of, and interaction between, iron and phosphorus control biological activity and fluxes in the subtropical North Atlantic."
When was the programme active?
The project was carried out in 2004.
Brief summary of the programme fieldwork/data
An experimental area in international waters to the west of the Canary Islands was selected following an intense period of vertical and horizontal mapping by the Charles Darwin. Using SF6 as a tracer for amended waters, two separate experiments were performed: The first (5th - 15th May) involved the addition of 20 tonnes of anhydrous monosodium phosphate at 10 m depth over an area of approximately 25 km2, centered at 27.8 oN 23.3 oW. The second experiment was conducted following a mid-cruise return by the Poseidon to Tenerife between 16th May and 22nd May, at 27.5 oN 22.5 oW, when 5 tonnes of acidified iron sulphate were added over the first 12 hours, then following a brief recovery period, 20 tonnes of phosphate added over the top of the iron.
Measurements of nutrient chemistry, gas exchange and biological activity were monitored prior to and after deployment (IN stations) of the fertilised patches relative to several (OUT) control stations.
Data Activity or Cruise Information
Data Activity
| Start Date (yyyy-mm-dd) | 2004-05-07 |
| End Date (yyyy-mm-dd) | 2004-05-07 |
| Organization Undertaking Activity | Newcastle University School of Marine Science and Technology |
| Country of Organization | United Kingdom |
| Originator's Data Activity Identifier | CD156_CTD_C035 |
| Platform Category | lowered unmanned submersible |
BODC Sample Metadata Report for CD156_CTD_C035
| 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| 648185 | 10.00 | 13 | 1 | 80.30 | 80.80 | 80.00 | Lever Action Niskin Bottle | No problem reported | ||
| 648188 | 10.00 | 14 | 2 | 70.20 | 70.90 | 70.10 | Lever Action Niskin Bottle | No problem reported | ||
| 648191 | 10.00 | 15 | 3 | 60.70 | 61.30 | 60.60 | Lever Action Niskin Bottle | No problem reported | ||
| 648194 | 10.00 | 16 | 4 | 61.00 | 61.40 | 60.80 | Lever Action Niskin Bottle | No problem reported | ||
| 648197 | 10.00 | 17 | 5 | 51.10 | 51.30 | 50.90 | Lever Action Niskin Bottle | No problem reported | ||
| 648200 | 10.00 | 18 | 6 | 41.30 | 41.60 | 41.20 | Lever Action Niskin Bottle | No problem reported | ||
| 648203 | 10.00 | 19 | 7 | 27.20 | 27.60 | 27.20 | Lever Action Niskin Bottle | No problem reported | ||
| 648206 | 10.00 | 20 | 8 | 26.90 | 27.20 | 26.90 | Lever Action Niskin Bottle | No problem reported | ||
| 648209 | 10.00 | 12 | 9 | 27.00 | 27.30 | 27.00 | Lever Action Niskin Bottle | No problem reported | ||
| 648212 | 10.00 | 21 | 10 | 15.90 | 16.50 | 16.10 | Lever Action Niskin Bottle | No problem reported | ||
| 648215 | 10.00 | 22 | 11 | 11.10 | 11.60 | 11.30 | Lever Action Niskin Bottle | No problem reported | ||
| 648218 | 10.00 | 23 | 12 | 4.20 | 4.40 | 4.30 | Lever Action Niskin Bottle | No problem reported | ||
| 648221 | 10.00 | 24 | 13 | 3.90 | 4.30 | 4.10 | Lever Action 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 | CD156 |
| Departure Date | 2004-04-26 |
| Arrival Date | 2004-05-23 |
| Principal Scientist(s) | Nicholas J P Owens (Newcastle University School of Marine Science and Technology) |
| Ship | RRS Charles Darwin |
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 |
