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Metadata Report for BODC Series Reference Number 1273855

Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
Niskin bottle  discrete water samplers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr Gary Fones
Originating Organization University of Portsmouth School of Earth and Environmental Sciences
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) -

Data Identifiers

Originator's Identifier PO314_CTD_NUTS_3528:CT314415
BODC Series Reference 1273855

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2004-07-14 00:18
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -

Spatial Co-ordinates

Latitude 57.36750 N ( 57° 22.1' N )
Longitude 10.67217 W ( 10° 40.3' W )
Positional Uncertainty Unspecified
Minimum Sensor or Sampling Depth 42.8 m
Maximum Sensor or Sampling Depth 2056.6 m
Minimum Sensor or Sampling Height 8.4 m
Maximum Sensor or Sampling Height 2022.2 m
Sea Floor Depth 2065.0 m
Sea Floor Depth Source -
Sensor or Sampling Distribution Unspecified -
Sensor or Sampling Depth Datum Unspecified -
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface


BODC CODERankUnitsTitle
ADEPZZ011MetresDepth (spatial coordinate) relative to water surface in the water body
BOTTFLAG1Not applicableSampling process quality flag (BODC C22)
NTRZAATX1Micromoles per litreConcentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
PHOSAATX1Micromoles per litreConcentration of phosphate {PO43- CAS 14265-44-2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
ROSPOSID1DimensionlessBottle rosette position identifier
SAMPRFNM1DimensionlessSample reference number
SLCAAATX1Micromoles per litreConcentration of silicate {SiO44- CAS 17181-37-2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis

Definition of BOTTFLAG

0The sampling event occurred without any incident being reported to BODC.
1The filter in an in-situ sampling pump physically ruptured during sample resulting in an unquantifiable loss of sampled material.
2Analytical 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.
3The 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.
4During 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.
5Water was reported to be escaping from the bottle as the rosette was being recovered.
6The bottle seals were observed to be incorrectly seated and the bottle was only part full of water on recovery.
7Either 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).
8There is reason to doubt the accuracy of the sampling depth associated with the sample.
9The bottle air vent had not been closed prior to deployment giving rise to a risk of sample contamination through leakage.

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

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.


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.

RV Poseidon Cruise PO314 Discrete inorganic nutrient (nitrate, silicate and phosphate) concentrations from CTD bottles

Cruise Details

Dates 11 Jul - 23 Jul 2004
Principal Scientific Officer Jane Read (National Oceanography Centre, Southampton)
Data Originator Gary Fones (University of Portsmouth)

Content Of Data Series

Parameter Units BODC Parameter code No. of Samples Comments
Inorganic nitrate µmol l-1 NTRZAATX 721 Nitrate = nitrate+nitrite
Inorganic silicate µmol l-1 SLCAAATX 721  
Inorganic phosphate µmol l-1 PHOSAATX 721  

Originator's Data Acquisition and Processing

Sampling Strategy

The cruise was designed to repeat the hydrographic section from Scotland to Rockall, called the Ellett Line, and its extension to Iceland. 73 stations were worked with CTD and lowered ADCP and sampled for chemical (macro- nutrients and dissolved oxygen) and biological (chlorophyll a) analyses. Depths of the CTD profiles ranged from 27m to 2685m. At shallow stations (~100m depth) Niskin bottles were typically fired at ~3 depths. For deeper stations 2 bottles were fired at the bottom, 3 to 4 bottles in the upper mixed layer and the others at regularly spaced or targeted intervals in the profile.

Instrumentation and Methodology

A total of 73 CTD casts were completed on the cruise, using a 12-way frame arrangement from which CTD bottle samples were taken with the following equipment:

Sea-Bird 9/11+ CTD
Sea-Bird 12 position Carousel
12 by 10L General Oceanics Niskin bottles

Inorganic nutrient measurements from each bottle were derived as follows:
Analysis for nitrate + nitrite (hereinafter nitrate), phosphate and silicate was undertaken on a Skalar Sanplus autoanalyser following methods described by Kirkwood (1996) with the exception that the pump rates through the phosphate line are increased by a factor of 1.5 which improves reproducibility and peak shape. Samples were drawn from 10 L Niskin bottles into 25ml sterilin coulter counter vials and kept refrigerated at 4°C until analysis which commenced within 24 hours. Stations were run in batches of 4-8 depending on sampling frequency regulated by depth of station. Stations were generally run in batches of 4-7 with most runs containing 4 or 5 stations. In total 73 stations were sampled over an 11 day period requiring 12 runs to be undertaken on the autoanalyser, with a total of 722 samples being analysed (not including standards, blanks or replicates).
An artificial seawater matrix (ASW) of 40 g/l sodium chloride was used as the intersample wash and standard matrix. The nutrient free status of this solution was checked by running Ocean Scientific International (OSI) nutrient free seawater on every run. A single set of mixed standards were made up at the start of the cruise and used throughout the cruise, new standards were made as and when they were needed. These were made using OSI nutrient standard solutions (Nitrate and Silicate, 1000 µm; phosphate, 100 µm) by diluting the solutions with ASW into 250 mL plastic volumetric flasks that had been cleaned by soaking for 6 weeks in MQ water. Standards used were 20, 10, 5 µm for nitrate and silicate and 2, 1, 0.5 µm for phosphate. This was in an effort to minimise the run to run variability in concentrations observed on previous cruises. An OSI nutrient standard solution of 10 µm nitrate and silicate and 1 µm phosphate was made fresh every two days and run routinely after every 15-20 samples to monitor the analytical drift and to ascertain the accuracy of the technique along with monitoring the potential degradation of the standards over the 12 day period. The efficiency of the Cd reduction column was monitored by running a nitrite standard every run. Initially a standard of 10 µm was made but this appeared to have degraded after only three days giving greater than 100% efficiency. Due to the limited amount of Nitrite stock (100 µm, 50 mL) a standard of 2 µm was made fresh every other day to monitor the column efficiency, this approach was successful giving an efficiency close to 100% with no degradation.

Further information about data quality can be found on p.33 of the cruise report.

Data Processing

Data processing was undertaken using Skalar propriety software.

BODC Data Processing

Data arrived at BODC in the form of Pstar files generated by the established Seabird CTD data processing routines. These files were converted into a single Comma Separated Value (csv) format file in Microsoft Excel. The data were then loaded into the BODC database using established BODC data banking procedures. The source files were the most processed and accurate version of the data, and these data were uploaded to an sqlplus table which included the following headings:

Originator's Parameter Originator's Units Parameter description BODC Parameter code BODC Units Comments
Nitrate 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=nitrate+nitrite
Silicate 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  
Phosphate 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  

Data Quality Report

Please refer to p.33 of the cruise report.

Problem Report


BODC Quality Control Flags

No quality control flags applied to this dataset by either the data originator or BODC.

Cruise Summary

RV Poseidon cruise 314 set out to occupy the 'Extended Ellett Line' Scotland - Rockall - Iceland time series. The objectives of doing so were:
1. To observe water mass properties, the instantaneous velocity field and subsequently the heat and salt (freshwater) fluxes between the subpolar gyre and the Nordic Seas in 2004.
2. To compare the 2004 conditions with those observed in the previous years (to 1975 in Rockall Trough, 1988 in the Iceland Basin), quantifying the interannual to decadal changes in properties and understanding the causal mechanisms of variability.
3. To enhance the physical and tracer measurements with biological observations to investigate nutrient cycling, export production, ecosystem structure and dynamics.

Project Summary

Oceans 2025 is a five-year programme, funded by the Natural Environment Research Council (NERC). It is designed by and implemented through seven leading UK marine centres. Oceans 2025 addresses some key challenges that the UK faces as a result of a changing marine environment. It will increase our understanding of the size, nature and impacts of these changes and will:

  • improve our knowledge of how the seas behave, not just now but in the future;
  • help to assess what that might mean for the Earth system and for society;
  • assist in developing sustainable solutions for the management of marine resources for future generations
  • enhance the research capabilities and facilities available for UK marine science.

The marine centres are working together in coordination and will also be supported by cooperation and input from government bodies, universities and other partners.For more information on this project, please go to the Oceans 2025 website.

Extended Ellett Line

The Extended Ellett Line is a time series of CTD stations which monitors the N. E. Atlantic current extension through the Iceland Basin, the recirculation of the eastern subpolar gyre and the Iceland Scotland overflow. It is an extension of the Ellett Line time series first occupied in 1975. The Extended Ellett Line consists of 57 standard stations which run from Scotland through Rockall and from Rockall to Iceland. Measurements at these stations or close to these stations lie within a box bounded by co-ordinates 56° 40.02'N, 020° 00.00'W at the southwest corner and 63° 17.52'N, 006° 07.98'W at the northeast corner.

The time series is maintained by the Scottish Association for Marine Science (SAMS) and the National Oceanography Centre, Southampton (NOC). Funds for the NOC and SAMS efforts are provided by the Natural Environment Research Council. Additional sections are periodically carried out by the Fisheries Research Services at Marine Laboratory, Aberdeen. The Ellett Line time series is part of the UK climate monitoring strategy, with core funding provided by government agencies. Additional funding is periodically obtained by the participating institutes to carry out detailed research into particular aspects of the section and the region.

For further details, please see the Extended Ellett Line website.


(1) Kirkwood, D (1996) Nutrients: Practical notes on their determination in sea water. ICES techniques in marine environmental sciences. No. 17, 25pp.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2004-07-13
End Date (yyyy-mm-dd) 2004-07-14
Organization Undertaking ActivitySouthampton Oceanography Centre (now National Oceanography Centre, Southampton)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPO314_CTD_CT314415
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for PO314_CTD_CT314415

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
782348   10.00 1   2085.10 2086.10 2056.10 Niskin bottle No problem reported    
782351   10.00 2   2085.60 2086.60 2056.60 Niskin bottle No problem reported    
782354   10.00 3   1819.80 1820.80 1795.70 Niskin bottle No problem reported    
782357   10.00 4   1514.50 1515.50 1495.60 Niskin bottle No problem reported    
782360   10.00 5   1009.10 1010.10  997.90 Niskin bottle No problem reported    
782363   10.00 6    652.90  653.90  646.40 Niskin bottle No problem reported    
782366   10.00 7    500.70  501.70  496.00 Niskin bottle No problem reported    
782369   10.00 8    197.10  198.10  195.70 Niskin bottle No problem reported    
782372   10.00 9    103.00  104.00  102.50 Niskin bottle No problem reported    
782375   10.00 10     62.40   63.40   62.30 Niskin bottle No problem reported    
782378   10.00 11     42.70   43.70   42.80 Niskin bottle No problem reported    
782381   10.00 12     12.40   13.40   12.80 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 Name PO314
Departure Date 2004-07-11
Arrival Date 2004-07-23
Principal Scientist(s)Jane F Read (Southampton Oceanography Centre)
Ship FS Poseidon

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