Metadata Report for BODC Series Reference Number 1362557
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
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Time Co-ordinates(UT) |
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Parameters |
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Problem Reports
No Problem Report Found in the Database
Data Access Policy
Open Data
These data have no specific confidentiality restrictions for users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.
If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:
"Contains public sector information licensed under the Open Government Licence v1.0."
Narrative Documents
Non-toxic (underway) sea water supply
A source of uncontaminated near-surface (commonly 3 to 7 m) seawater pumped continuously to shipboard laboratories on research vessels. There is typically a temperature sensor near the intake (known as the hull temperature) to provide measurements that are as close as possible to the ambient water temperature. The flow from the supply is typically directed through continuously logged sensors such as a thermosalinograph and a fluorometer. Water samples are often collected from the non-toxic supply. The system is also referred to as the underway supply.
Nitrate, nitrite, phosphate, silicate and ammonium seawater concentrations for BAS cruise JR20011231
Originator's data acquisition and analysis
Discrete samples were taken using a CTD water bottle rosette that was triggered at different depths of the water column and from the ship's non toxic water supply, located at 7 m below the surface. Discrete samples were subsampled and passed through a mixed ester membrane (Whatman WME, pore size 0.45 µm; pre-soaked in dilute HCl and rinsed with water). All analyses were conducted using a nutrient autoanalyser made up of Technicon MK II single channel colorimeters and Ismatec pumps and custom built reaction manifolds.
Nitrite Nitrite was determined following the method described by Folkard (1978). Nitrite ions diazotise sulphanilamide then couple with N-1-naphthylethylenediamine dihydrochloride to form an azo-dye, the concentration of which is measured by absorbance at 550 nm.
Nitrate Determination of nitrate was conducted following the method described by Stainton (1974). Nitrate is reduced to nitrite by passing the sample stream through a transmission tube containing a copper-coated cadmium wire. Nitrite ions diazotise sulphanilamide then couple with N-1-naphthylethylenediamine dihydrochloride to form an azo-dye, the concentration of which is measured by absorbance at 550 nm.
Phosphate Phosphate concentration was determined following a method similar to that described by Tréguer and Le Corre (1975). Orthophosphate ions react with acidified ammonium molybdate in the presence of antimony to form phosphomolbdic acid. This is reduced by ascorbic acid to a 'molydenum blue' complex (Riley and Skirrow, 1975) the concentration of which is measured by absorbance at 630nm.
Silicate The concentration of silicate in seawater was determined using a method based on an industrial method by Technicon (1976). Silicate ions react with ammonium molybdate in acidic conditions producing silicomolybdic acid. This is reduced to a 'molybdenum blue' complex by ascorbic acid (Riley and Skirrow, 1975) and its concentration is measured by absorbance at 660 nm.
Ammonium Ammonia is determined using a variant of the Berthelot reaction. Sodium dichloroisocyanurate is used as a hypochlorite donor (Krom, 1984) and catalysis is performed by potassium ferrocyanide. After reagent additions, the reaction stream is heated to 40°C and formation of 'indophenol blue' is promoted under longwave UV radiation (365 nm). Concentration is measured by absorbance at 630 nm.
See Whitehouse, 1997 for full details of all instrumentation and analysis involved.
References cited
Folkard A.R., 1978 Automatic analysis of seawater nutrients. Fisheries Technical Report, 46, 23.
Krom M.D., 1984 Spectrophotometric determination of ammonia. A study of a modified Berthelot reaction using salicylate and dichloroisocyanurate. The Analyst, 105, 305-316.
Riley J.P. and Skirrow G., 1975. Chemical Oceanography, 3, (2nd Edition), London, Academic Press.
Stainton M.P., 1974. Simple, efficient reduction column for use in the automated determination of nitrate in water. Analytical Chemistry, 46, 1616.
Technicon Instruments Corporation, 1976. Silicates in water and wastewater. Technicon industrial method No 105-71.
Tréguer P. and Le Corre P., 1975. Manuel d'analyse des sels nutritifs dans l'eau de mer (Utilisation de l'AutoAnalyser II, Technicon, 2nd edition). Report laboratoire d'oceanologie chimique, Université de Bretagne Occidentale, Brest, France.
Whitehouse M.J., 1997. Automated Seawater Nutrient Chemistry. British Antarctic Survey, Cambridge.
BODC Data Processing Procedures
Data were received by BODC in spreadsheet format with the nutrient data from various BAS cruises in labeled worksheets (BAS_nutrient_data_1981-2009.xls). The following metadata fields were also included with the data: cruise ID, date, latitude, longitude, event number and pressure.
Several samples were sent without a corresponding sampling pressure.It was not possible to match these samples against any other source of information stored in BODC's archives, which resulted in them not being loaded. The samples were collected on casts JR70_140, 148, 162, 259, 266, 274, 277 and 285.
Parameter codes defined in the BODC parameter dictionary were mapped to the variables as follows:
| Originator's Parameter | Units | Description | BODC Parameter Code | Units | Comments |
|---|---|---|---|---|---|
| NO3 | mmol m-3 | concentration of nitrate + nitrite per unit volume of the water body (dissolved plus reactive particulate <0.4 µm phase) | NTRZAAD2 | µmol L-1 | No unit conversion necessary, units analogous with one another |
| NO2 | mmol m-3 | concentration of nitrite per unit volume of the water body (dissolved plus reactive particulate <0.4 µm phase) | NTRIAAD2 | µmol L-1 | No unit conversion necessary, units analogous with one another |
| NH4 | mmol m-3 | concentration of ammonium per unit volume of the water body (dissolved plus reactive particulate <0.4 µm phase) | AMONAAD2 | µmol L-1 | No unit conversion necessary, units analogous with one another |
| PO4 | mmol m-3 | concentration of phosphate per unit volume of the water body (dissolved plus reactive particulate <0.4 µm phase) | PHOSAAD2 | µmol L-1 | No unit conversion necessary, units analogous with one another |
| Si | mmol m-3 | concentration of silicate per unit volume of the water body (dissolved plus reactive particulate <0.4 µm phase) | SLCAAAD2 | µmol L-1 | No unit conversion necessary, units analogous with one another |
Nutrient data were received with no associated time for the sampling event. It was therefore deemed necessary to acquire times from the cruise event log, using the event numbers to map the correct times to the nutrient sampling events.
The depth of the water column at each sampling event has been assigned using GMT and GEBCO data.
The data were banked according to BODC standard procedures for sample data. Data were banked as received, with no averaging or other modifications applied.
Data Quality Report
Several events appear to have samples collected at a depth lower than the water column depth. This data was checked and is correct, however there is no way to confirm the correct water column depth and the only available source of bathymetry data is from the GEBCO database.
Project Information
Dynamics of Ocean Management- DYNAMOE
Introduction
DYNAMOE was created in order to provide data for the global management of finfish communities, squid and krill and avoid future long-term damage from over-fishing. The understanding of how the ocean ecosystem works provides scientists with the tools to predict how human activity and climate changes will affect the Southern Ocean environment and how biological communities will respond. This programme will cover a period from March 2000 to April 2005 and is part of the British Antarctic Survey research programme Antarctic Science in the Global Context.
The research will be concentrated on the Scotia Sea, particularly the food-web and fishery dynamics around South Georgia using the sampling facilities on the RRS James Clark Ross, including vertical profiling for temperature and salinity measurements, sensory and acoustic systems for ocean currents measurements and plankton, fish and squid mapping and nets for biological specimens.
The land-based studies will take place at Bird Island, South Georgia following a year-round study of seabirds and marine mammals which will provide an assessment of breeding performance, growth, diet and foraging.
The programme will integrate interdisciplinary studies in population and food webs modelling, as well as develop satellite-tracking capabilities to link the land-based predator studies to the ship-based ocean analyses.
This programme encompasses two projects:
- Dynamics of pelagic organisms in Southern Ocean ecosystems
- Dynamics of predators and fisheries in Southern Ocean ecosystems
Scientific Objectives
The main objectives are:
- Develop a spatial analysis of how the Southern Ocean ecosystems work
- Quantify the importance of ocean currents in the transport of biological material in the Southern Ocean food-webs
- Examine how Southern Ocean ecosystems respond to variability and change, focusing on links between krill and predators
- Develop an ecosystem approach to the management of Southern ocean fisheries
Data Availability
Data sets collected during this project are available to the academic community.
Data Activity or Cruise Information
Cruise
| Cruise Name | JR20011231 (JR70) |
| Departure Date | 2001-12-31 |
| Arrival Date | 2002-02-08 |
| Principal Scientist(s) | Peter Ward (British Antarctic Survey) |
| Ship | RRS James Clark Ross |
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 |
