Metadata Report for BODC Series Reference Number 1126751
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 Quality Report - see processing documentation
Data quality information is included in the general documentation for this series. Please read.
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
SPX Bran+Luebbe Autoanalyser 3
The instrument uses continuous flow analysis (CFA) with a continuous stream of material divided by air bubbles into discrete segments in which chemical reactions occur. The continuous stream of liquid samples and reagents are combined and transported in tubing and mixing coils. The tubing passes the samples from one apparatus to the other with each apparatus performing different functions, such as distillation, dialysis, extraction, ion exchange, heating, incubation, and subsequent recording of a signal.
An essential principle of the system is the introduction of air bubbles. The air bubbles segment each sample into discrete packets and act as a barrier between packets to prevent cross contamination as they travel down the length of the tubing. The air bubbles also assist mixing by creating turbulent flow (bolus flow), and provide operators with a quick and easy check of the flow characteristics of the liquid.
Samples and standards are treated in an exactly identical manner as they travel the length of the tubing, eliminating the necessity of a steady state signal, however, since the presence of bubbles create an almost square wave profile, bringing the system to steady state does not significantly decrease throughput and is desirable in that steady state signals (chemical equilibrium) are more accurate and reproducible.
The autoanalyzer can consist of different modules including a sampler, pump, mixing coils, optional sample treatments (dialysis, distillation, heating, etc), a detector, and data generator. Most continuous flow analyzers depend on color reactions using a flow through colorimeter, however other methods have been developed that use ISE, flame photometry, ICAP, fluorometry, and so forth.
More details can be found in the manufacturer's introduction to autoanalysers andinstrument description.
World Precision Instruments Liquid Waveguide Capillary Cell
Liquid Waveguide Capillary Cell (LWCC) is a flow cell for absorbance measurements in the ultraviolet, visible and near infra-red ranges. Pathlengths range from 50-500cm, with increasing measurement sensitivity from 50 to 500-fold. The flow cells are fiber coupled and have a very small sample volume ranging from 125µL (50cm pathlength) to 1,250µL (500cm pathlength).
The sample solution is introduced into the LWCC at the liquid input. Light is coupled into the LWCC from a light source via a fiber optic cable. After passing through the LWCC, light is collected with an optical fiber and guided to a detector. The concentration of the sample is determined by measuring its absorbance in the LWCC, similar to a standard UV/VIS spectrometer.
Specifications
| Model | LWCC-3050 | LWCC-3100 | LWCC-3250 | LWCC-3500 |
| Optical Pathlength | 50cm | 100cm | 250cm | 500cm |
| Internal Volume | 125µL | 250µL | 625µL | 1250µL |
| Fiber Connection | 500um SMA | |||
| Transmission @254nm* | 20 | 10 | 5 | - |
| Transmission @540nm* | 35 | 30 | 25 | 20 |
| Noise [mAU]** | <0.1 | <0.2 | <0.5 | <1.0 |
Maximum Pressure 100 PSI
Wetted Material PEEK, Fused Silica, PTFE
Liquid Input Standard 10-32 Coned Port Fitting
* Referenced using coupled 500µm fibers
** Measured using ASTM E685-93
*** A one-meter waveguide of 550µm internal diameter requires approximately 1.5 psi for water flow of 1.0 mL/min.
Further details can be found in the manufacturer's specification sheet.
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.
AMT15 Nutrient (micro- and nano-molar) measurements from CTD bottle and underway surface samples
Originator's Protocol for Data Acquisition and Analysis
Water samples were taken from the Sea-Bird CTD rosette system. The micro-molar samples were collected into acid-clean 60 ml HDPE (nalgene) sample bottles and the nano-molar samples into 120 ml HDPE (nalgene) sample bottles. Analysis for nutrients was completed within 2 hours for mirco-molar and 3 hours for nano-molar measurements in all cases. Clean handling techniques were employed to avoid contamination of the samples. Nano-molar measurements were also made from samples collected underway each day at 15:00 from the ship's non-toxic supply where concentrations were lower than the detectible level from micro-molar analysis on sea-water.
The main nutrient analyser was a 5-channel Bran and Luebbe AAIII segmented flow autoanalyser. The analytical chemical methodologies used were according to Brewer and Riley (1965) for nitrate, Grasshoff (1976) for nitrite, Kirkwood (1989) for phosphate and silicate, and Mantoura and Woodward (1983) for ammonium.
Nanomolar ammonium concentrations were obtained using an adapted method from Jones (1991); this uses a fluorescent analysis technique following ammonia gas diffusion out of the samples, passing across a hydrophobic Teflon membrane due to differential pH chemistry.
Nanomolar nitrate+nitrite, nitrate 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). The nitrate and nitrate systems worked throughout the cruise but due to time constraints the phosphate system was only used in the Southern Gyre region and beyond.
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.
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.
BODC Data Processing Procedures
The micro and nano-molar nutrient data were submitted to BODC in two separate Microsoft Excel files. There was no micro- or nanomolar ammonium data in the files provided to BODC.
Station and sample metadata were checked against information held in the BODC database and obtained from the SeaBird CTD log files, scientific logs and reports. There were some discrepancies. For one cast (cast 105) this was due to an obvious mislabelling of the cast number in the originator's file. Other significant discrepancies in sample depths are listed in a table in the Problem Report section below.
Data from the LWCC systems were submitted in units of nmol l-1. Nano-molar data were divided by 1000 to convert the units to µmol l-1 for storage in the database.Users should be aware that these LWCC measurements are valid to the fourth decimal place. The data were assigned parameter codes defined in BODC parameter dictionary. Data loaded into BODC's database using established BODC data banking procedures.
A parameter mapping table is provided below;
| Originator's Parameter | Units | Description | BODC Parameter Code | Units | Comments |
|---|---|---|---|---|---|
| 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 | - |
Data Quality Report
The dataset has been checked by the data originator - any suspect data values were removed from the data set before submission to BODC.
Measurement precision information from data originators
The detection limits for measurements from the AAIII Bran and Luebbe autoanalyser have are 0.02 µmol l-1, except the colorimetric ammonium which has a detection limit of 0.08 µmol l-1. Samples in the database with a flag of "<" had concentrations below the specified detection limits.
At low concentrations, the values obtained by the LWCC are likely to be more accurate than those from the AAIII analyser.
Problem Report
Because of a few remaining uncertainties in matching sample measurements with SeaBird bottle firing depths, users should exert caution when using data from the following CTD cast and depth (records marked with an asterisk are believed to be due to typographical errors in the source files):
| CTD Cast ID | Originator Bottle No. | Originator Sample Depth | BODC Bottle No. | BODC Depth | BODC Bottle ID | Micro or nano-molar dataset |
|---|---|---|---|---|---|---|
| 21 | 3 | 2300* | 3 | 201.1 | 513905 | Nano |
| 59 | 19 | 40 | 19 | 20.2 | 514475 | Nano |
| 59 | 17 | 50 | 17 | 40.3 | 514473 | Nano |
| 59 | 16 | 60 | 16 | 50 | 514472 | Nano |
| 68 | 24 | 2 | 21 | 16.5 | 513214 | Nano |
| 4 | 5 | 150.0 | 5 | 158.7 | 514934 | Micro |
| 4 | 3 | 200.0 | 3 | 211.6 | 514932 | Micro |
| 4 | 1 | 300.0 | 1 | 319.3 | 514930 | Micro |
| 18 | 12 | 60.0 | 12 | 52 | 513874 | Micro |
| 48 | 6 | 15.0* | 6 | 125.3 | 514532 | Micro |
| 59 | 19 | 40.0 | 19 | 20.2 | 514475 | Micro |
| 59 | 17 | 50.0 | 17 | 40.3 | 514473 | Micro |
| 59 | 16 | 60.0 | 16 | 50 | 514472 | Micro |
| 59 | 15 | 70.0 | 15 | 60.2 | 514471 | Micro |
| 59 | 13 | 75.0 | 13 | 69.8 | 514469 | Micro |
| 59 | 6 | 15.0* | 6 | 125.3 | 514462 | Micro |
| 65 | 20 | 10.0 | 20 | 17.6 | 513323 | Micro |
| 65 | 16 | 20.0 | 16 | 27.6 | 513319 | Micro |
| 65 | 12 | 60.0 | 12 | 47.8 | 513315 | Micro |
| 65 | 7 | 80.0 | 7 | 101.2 | 513310 | Micro |
| 65 | 6 | 90.0 | 6 | 121.6 | 513309 | Micro |
| 65 | 4 | 100.0 | 4 | 152.5 | 513307 | Micro |
| 65 | 3 | 150.0 | 3 | 177.4 | 513306 | Micro |
Project Information
The Atlantic Meridional Transect - Phase 2 (2002-2006)
Who was involved in the project?
The Atlantic Meridional Transect Phase 2 was designed by and implemented by a number of UK research centres and universities. The programme was hosted by Plymouth Marine Laboratory in collaboration with the National Oceanography Centre, Southampton. The universities involved were:
- University of Liverpool
- University of Newcastle
- University of Plymouth
- University of Southampton
- University of East Anglia
What was the project about?
AMT began in 1995, with scientific aims to assess mesoscale to basin scale phytoplankton processes, the functional interpretation of bio-optical signatures and the seasonal, regional and latitudinal variations in mesozooplankton dynamics. In 2002, when the programme restarted, the scientific aims were broadened to address a suite of cross-disciplinary questions concerning ocean plankton ecology and biogeochemistry and the links to atmospheric processes.
The objectives included the determination of:
- how the structure, functional properties and trophic status of the major planktonic ecosystems vary in space and time
- how physical processes control the rates of nutrient supply to the planktonic ecosystem
- how atmosphere-ocean exchange and photo-degradation influence the formation and fate of organic matter
The data were collected with the aim of being distributed for use in the development of models to describe the interactions between the global climate system and ocean biogeochemistry.
When was the project active?
The second phase of funding allowed the project to continue for the period 2002 to 2006 and consisted of six research cruises. The first phase of the AMT programme ran from 1995 to 2000.
Brief summary of the project fieldwork/data
The fieldwork on the first three cruises was carried out along transects from the UK to the Falkland Islands in September and from the Falkland Islands to the UK in April. The last three cruises followed a cruise track between the UK and South Africa, only deviating from the traditional transect in the southern hemisphere. During this phase the research cruises sampled further into the centre of the North and South Atlantic Ocean and also along the north-west coast of Africa where upwelled nutrient rich water is known to provide a significant source of climatically important gases.
Who funded the project?
Natural Environment Research Council (NERC)
Data Activity or Cruise Information
Data Activity
| Start Date (yyyy-mm-dd) | 2004-09-20 |
| End Date (yyyy-mm-dd) | 2004-09-20 |
| Organization Undertaking Activity | Plymouth Marine Laboratory |
| Country of Organization | United Kingdom |
| Originator's Data Activity Identifier | AMT15_CTD_CTD004t |
| Platform Category | lowered unmanned submersible |
BODC Sample Metadata Report for AMT15_CTD_CTD004t
| 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| 514930 | 10.0 | 1 | 1 | 321.80 | 322.80 | 319.30 | Lever Action Niskin Bottle | No problem reported | ||
| 514931 | 10.0 | 2 | 2 | 270.20 | 270.80 | 268.10 | Lever Action Niskin Bottle | No problem reported | ||
| 514932 | 10.0 | 3 | 3 | 213.10 | 214.00 | 211.60 | Lever Action Niskin Bottle | No problem reported | ||
| 514933 | 10.0 | 4 | 4 | 213.10 | 214.80 | 212.00 | Lever Action Niskin Bottle | No problem reported | ||
| 514934 | 10.0 | 5 | 5 | 159.70 | 160.60 | 158.70 | Lever Action Niskin Bottle | No problem reported | ||
| 514935 | 10.0 | 6 | 6 | 128.60 | 129.00 | 127.70 | Lever Action Niskin Bottle | No problem reported | ||
| 514936 | 10.0 | 7 | 7 | 129.00 | 129.20 | 128.00 | Lever Action Niskin Bottle | No problem reported | ||
| 514937 | 10.0 | 8 | 8 | 127.10 | 127.90 | 126.40 | Lever Action Niskin Bottle | No problem reported | ||
| 514938 | 10.0 | 9 | 9 | 128.20 | 129.00 | 127.50 | Lever Action Niskin Bottle | No problem reported | ||
| 514939 | 10.0 | 10 | 10 | 126.50 | 126.80 | 125.50 | Lever Action Niskin Bottle | No problem reported | ||
| 514940 | 10.0 | 11 | 11 | 128.80 | 130.30 | 128.40 | Lever Action Niskin Bottle | No problem reported | ||
| 514941 | 10.0 | 12 | 12 | 126.00 | 127.90 | 125.80 | 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 | D284 (AMT15) |
| Departure Date | 2004-09-17 |
| Arrival Date | 2004-10-29 |
| Principal Scientist(s) | Andrew Rees (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 |
