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Metadata Report for BODC Series Reference Number 1351916


Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
NameCategories
Niskin bottle  discrete water samplers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr Anna Hickman
Originating Organization National Oceanography Centre, Southampton
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) Seasonal Thermocline Production Control
 

Data Identifiers

Originator's Identifier CD173_CTD_NUTS_229:CTD031
BODC Series Reference 1351916
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2005-07-23 15:25
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 48.57739 N ( 48° 34.6' N )
Longitude 9.48150 W ( 9° 28.9' W )
Positional Uncertainty Unspecified
Minimum Sensor or Sampling Depth 0.5 m
Maximum Sensor or Sampling Depth 175.4 m
Minimum Sensor or Sampling Height 10.1 m
Maximum Sensor or Sampling Height 185.0 m
Sea Floor Depth 185.5 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
 

Parameters

BODC CODERankUnitsTitle
ADEPZZ011MetresDepth (spatial coordinate) relative to water surface in the water body
BOTTFLAG1Not applicableSampling process quality flag (BODC C22)
FIRSEQID1DimensionlessBottle firing sequence number
NTRZAAZX1Micromoles per litreConcentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body [unknown phase] by colorimetric autoanalysis
PHOSAAZX1Micromoles per litreConcentration of phosphate {PO43- CAS 14265-44-2} per unit volume of the water body [unknown phase] by colorimetric autoanalysis
ROSPOSID1DimensionlessBottle rosette position identifier
SAMPRFNM1DimensionlessSample reference number
SLCAAAZX1Micromoles per litreConcentration of silicate {SiO44- CAS 17181-37-2} per unit volume of the water body [unknown phase] by colorimetric autoanalysis

Definition of BOTTFLAG

BOTTFLAGDefinition
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

Public domain 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.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."


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.

CD173 Discrete Nutrient Sampling Document

Originator's Protocol for Data Acquisition and Analysis

Water samples were taken during RRS Charles Darwin cruise CD173 which was conducted in the Celtic Sea from 15 July 2005 to 06 August 2005. 706 samples were collected during 84 casts, from rosette bottles fired at various depths throughout the water column. The collection depths were chosen on the basis of real-time fluoresence and temperature traces. With 25 exceptions, single samples were taken from rosette bottles. For the 25 exceptions, duplicate samples were taken and analysed.

All measurements for nitrate, phosphate and silicate were made on board using standard colorimetric methods (Grasshoff et al. 1983) with a Skalar AAII Autoanalyser.

References Cited

Grasshoff K. M., Erhardt M. K. and Kremling K., 1983. Methods of seawater analysis. Verlag-Chemie.

BODC Data Processing Procedures

The nutrient data were supplied to BODC in Microsoft Excel format. Values were extracted from this and saved in ASCII format prior to being loaded into the BODC Samples Database under the ORACLE Relational Database Management System. Methodology and units were checked against information held in the BODC parameter dictionary and an appropriate parameter code was attributed to each variable. Data that were considered unrealistic were flagged suspect. For duplicate samples, the mean concentration of each parameter from both samples was calculated and stored in the database, along with the corresponding standard deviation.

Content of data series

Originator's Parameter Unit Description BODC Parameter code BODC Unit Comment
N µmol l-1 Concentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body by colorimetric autoanalysis NTRZAAZX µmol l-1 Where duplicate samples taken, parameter value is a mean of duplicates
P µmol l-1 Concentration of phosphate {PO4} per unit volume of the water body by colorimetric autoanalysis PHOSAAZX µmol l-1 Where duplicate samples taken, parameter value is a mean of duplicates
S µmol l-1 Concentration of silicate {SiO4} per unit volume of the water body by colorimetric autoanalysis SLCAAAZX µmol l-1 Where duplicate samples taken, parameter value is a mean of duplicates
- - Concentration standard deviation of nitrate+nitrite {NO3+NO2} per unit volume of the water body [unknown phase] by colorimetric autoanalysis SDNTAAZX µmol l-1 Calculated by BODC from duplicate samples
- - Concentration standard deviation of phosphate {PO4} per unit volume of the water body [unknown phase] by colorimetric autoanalysis PHSDAAZX µmol l-1 Calculated by BODC from duplicate samples
- - Concentration standard deviation of silicate {SiO4} per unit volume of the water body [unknown phase] by colorimetric autoanalysis SLSDAAZX µmol l-1 Calculated by BODC from duplicate samples

Comments

The data supplied to BODC included numerous values which were below the limit of detection quoted by the Data Originator (0.1 µmol l-1) for the Skalar AAII Autoanalyser. These values were replaced with the instrument detection limit value and flagged accordingly.

For seven of the 25 duplicate samples, the concentrations of both replicates for NO3+NO2 and for PO4 were below the limit of detection. These replicates were not averaged and the value loaded to the database was the instrument detection limit. The values were flagged accordingly.

The Data Originator supplied concentrations from casts CTD029, CTD030, CTD032, CTD052 and CTD058 taken at 2 m depth. The CTD logs and electronic bottle firing records for these casts however had no record of bottles being fired at these depths. As a result of this discrepancy, these concentrations were not loaded into the database but are available from BODC on request.

For 30 of the 84 casts, multiple bottles were fired at the same depths. The Data Originator supplied the data linked by cast and depth, but not against specific bottles. BODC therefore took the decision to arbitrarily link the samples in the order they were supplied in the original spreadsheet to the bottles fired at that depth in sequence e.g. first sample at 25 m depth for cast CTD011 linked to bottle 14, second sample to bottle 15, third to bottle 16 and so on). The total number of samples which were linked in this manner was 119. The user should be aware that this linkage is arbitrary and may not be correct.


Project Information

Physical-Biological Control of New Production within the Seasonal Thermocline

This project was a NERC responsive-mode project which was co-funded by the Defence Science and Technology Laboratory and ran from 2003 to 2006. The key institutes and scientists involved were:

Institute Scientific personnel
Proudman Oceanographic Laboratory (POL) Jonathan Sharples
National Oceanography Centre, Southampton (NOCS) Patrick Holligan
Mark Moore
University of Wales, Bangor (UWB) John Simpson
Tom Rippeth

Research Aim

The main aim of this research was to investigate the generation and dissipation of turbulence in the thermocline, and to quantify how the resulting mixing (supplying nutrients and controlling the light experienced by the algae) affected the growth of phytoplankton within the sub-surface chlorophyll maximum (SCM).

Research Objectives

The objective of the research was to test the general hypothesis that, in seasonally-stratified shelf waters, temporal and spatial variability of the rate of 'new' production is determined by the degree of coupling between physical and biological processes within the seasonal thermocline. In particular it has been suggested that physiological adaptation by phytoplankton making up the subsurface chlorophyll maximum drives a biological pump for extracting nitrate from the bottom mixed layer that is sensitive to internal mixing and to external climatological factors.

Research Approach

The sampling and experimental strategy was based on established methods for obtaining compatible, high-resolution vertical profiles (alternate CTD and FLY) and sections (SeaSoar) of physical, chemical, and biological parameters, allowing quantification of vertical fluxes and primary production on tidal and internal wave time scales. The cruise schedule (with associated mooring deployments) for the project is below.

Cruise Schedule

Cruise ID Ship Sampling Region Cruise Dates Main measurements
JR98 RRS James Clark Ross St Georges Channel, Celtic Sea and shelf edge 25/07/03 - 14/08/03 CTD casts, SeaSoar transects (CTD, chlorophyll, fluorescence), FRRF, ship ADCP, primary productivity, nutrients, trace metals, phytoplankton uptake rates, algal photophysiology, oxygen concentration, particle size, optics, mooring deployments
PD32_03 RV Prince Madog Celtic Sea and shelf edge 27/07/03 - 13/08/03 5 x FLY 25 hour tidal cycle stations, particle size analysis, particle settling velocity, CTD casts, mooring deployments
CD173 RRS Charles Darwin Celtic Sea and shelf edge 15/07/05 - 06/08/05 CTD casts, chlorophyll, oxygen concentration, FLY profiles, SeaSoar tows (CTD, chlorophyll, FRRF), phytoplankton pigments, nutrients, primary productivity, phytoplankton uptake rates, FRRF profiles, optics, particle size analysis, mooring deployments
PD27_05 RV Prince Madog Celtic Sea and shelf edge 22/07/05 - 06/08/05 FLY profiles, mooring deployments

Moorings

Station ID Latitude Longitude Depth (m) Mooring Deployment date Recovery date Deployment vessel
CS3 51.471 -6.428 95 Seabed frame 300 kHz ADCP 01/08/03 11/08/03 RV Prince Madog
CS3 51.471 -6.428 95 Seabed frame 1200 kHz ADCP 01/08/03 11/08/03 RV Prince Madog
CS3 51.474 -6.437 95 Mid-water subsurface 300 kHz ADCP 01/08/03 11/08/03 RV Prince Madog
CS3 51.469 -6.437 95 Thermistor chain from 5 - 45 m depth 01/08/03 11/08/03 RV Prince Madog
ACW 51.266 -5.741 85 Seabed frame 300 kHz ADCP 06/08/03 08/08/03 RV Prince Madog
CS2 48.532 -9.463 200 Surface temperature toroid 28/07/03 12/08/03 RRS James Clark Ross
CS2 48.532 -9.463 200 Thermistor chain throughout water column 28/07/03 12/08/03 RRS James Clark Ross
CS2 48.532 -9.463 200 Sub-suface 600 kHz ADCP (90 m) 28/07/03 12/08/03 RRS James Clark Ross
CS2 48.532 -9.463 200 Aanderaa RCM7 current meter/CTD (12 mab)* 28/07/03 12/08/03 RRS James Clark Ross
CS2 48.532 -9.463 200 Seabed frame 150 kHz ADCP 28/07/03 12/08/03 RRS James Clark Ross
CS2 48.532 -9.463 200 Seabed frame 300 kHz ADCP 28/07/03 12/08/03 RRS James Clark Ross
U2 49.236 -6.166 121 Sub-suface 300 kHz ADCP (5 mab)* 15/07/05 03/08/05 RRS Charles Darwin
U2 49.233 -6.167 120 Thermistor chain throughout water column 19/07/05 Mooring lost RRS Charles Darwin
CS2 48.571 -9.509 200 Thermistor chain throughout water column 17/07/05 24/07/05 RRS Charles Darwin
CS2 48.573 -9.51 194 Sub-suface 300 kHz ADCP (100 m) 17/07/05 24/07/05 RRS Charles Darwin
CS2 48.572 -9.508 196 Seabed frame 300 kHz ADCP 17/07/05 24/07/05 RRS Charles Darwin
CS2 48.571 -9.507 202 Seabed frame 150 kHz ADCP 17/07/05 24/07/05 RRS Charles Darwin
Bank 1 49.938 -7.792 118 Thermistor chain throughout water column 26/07/05 Mooring lost RRS Charles Darwin
Bank 1 49.936 -7.792 118 Seabed frame 300 kHz ADCP 27/07/05 Recovered by trawler 29/07/05 RRS Charles Darwin
Bank 2 49.895 -7.872 114 Thermistor chain throughout water column 20/07/05 04/08/05 RRS Charles Darwin
Bank 2 49.876 -7.897 112 Sub-surface 600 kHz ADCP (56 m) 26/07/05 04/08/05 RRS Charles Darwin
Bank 2 49.894 -7.873 110 Seabed frame 300 kHz ADCP 26/07/05 04/08/05 RRS Charles Darwin
Bank 3 49.851 -7.952 78 Thermistor chain throughout water column 26/07/05 03/08/05 RV Prince Madog
Bank 3 49.854 -7.948 78 Seabed frame 300 kHz ADCP 26/07/05 Mooring lost RV Prince Madog

* = metres above seabed

Project Outcomes

The main products of the research were:

  • The first large scale interdisciplinary study of the dynamic processes that determine the properties of the SCM in NW European shelf waters.
  • Substantive advances in quantifying internal mixing in NW European shelf seas, and in understanding how primary production is controlled by this small-scale turbulence.
  • New parameterisations for internal vertical mixing, and the response of primary production, for use in coupled numerical models.
  • Improved capability for estimating primary productivity in stratified waters by satellite remote sensing (ocean colour, sea surface temperature, wind mixing etc.)
  • An overall development of our understanding of the dynamics of ecosystems that support important fisheries, and of our abilities in predicting ecological and biogeochemical responses to variations and changes in the climate of the marine environment.

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2005-07-23
End Date (yyyy-mm-dd) Ongoing
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierCD173_CTD_CTD031
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for CD173_CTD_CTD031

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
436228   20.00 1 1  177.60  178.60  175.40 Niskin bottle No problem reported    
436229   20.00 2 2  162.80  163.80  160.70 Niskin bottle No problem reported    
436230   20.00 3 3  142.40  143.40  140.50 Niskin bottle No problem reported    
436231   20.00 4 4  122.10  123.10  120.40 Niskin bottle No problem reported    
436232   20.00 5 5  102.40  103.40  100.90 Niskin bottle No problem reported    
436233   20.00 6 6   80.60   81.60   79.30 Niskin bottle No problem reported    
436234   20.00 7 7   61.50   62.50   60.30 Niskin bottle No problem reported    
436235   20.00 8 8   51.40   52.40   50.30 Niskin bottle No problem reported    
436236   20.00 9 9   41.30   42.30   40.30 Niskin bottle No problem reported    
436237   20.00 10 10   30.90   31.90   30.00 Niskin bottle No problem reported    
436238   20.00 11 11   21.20   22.20   20.40 Niskin bottle No problem reported    
436239   20.00 12 12   11.30   12.30   10.60 Niskin bottle No problem reported    
436240   20.00 13 13    1.10    2.10     .50 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.

Related Data Activity activities are detailed in Appendix 1

Cruise

Cruise Name CD173
Departure Date 2005-07-15
Arrival Date 2005-08-06
Principal Scientist(s)Jonathan Sharples (Proudman Oceanographic Laboratory)
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

Appendix 1: CD173_CTD_CTD031

Related series for this Data Activity are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.

Series IdentifierData CategoryStart date/timeStart positionCruise
1710398Water sample data2005-07-23 15:25:0048.57739 N, 9.4815 WRRS Charles Darwin CD173
2081482Water sample data2005-07-23 15:25:0048.57739 N, 9.4815 WRRS Charles Darwin CD173