Metadata Report for BODC Series Reference Number 1656021

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 Prof Paul Tett
Originating Organization Napier University School of Life Sciences (now Edinburgh Napier University School of Life, Sport & Social Sciences)
Processing Status banked
Project(s) Provess

Data Identifiers

Originator's Identifier VA174_CTD_PIGX_24:076_120
BODC Series Reference 1656021

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1998-09-11 07:30
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -

Spatial Co-ordinates

Latitude 59.32983 N ( 59° 19.8' N )
Longitude 1.03500 E ( 1° 2.1' E )
Positional Uncertainty Unspecified
Minimum Sensor Depth 7.0 m
Maximum Sensor Depth 91.8 m
Minimum Sensor Height 3.2 m
Maximum Sensor Height 88.0 m
Sea Floor Depth 95.0 m
Sensor Distribution Unspecified -
Sensor Depth Datum Unspecified -
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface


BODC CODE Rank Units Short Title Title
ADEPZZ01 1 Metres DepBelowSurf Depth below surface of the water body
BOTTFLAG 1 Dimensionless C22_flag Sampling process quality flag (BODC C22)
CAROSSP1 1 Milligrams per cubic metre Spec_Carot_>GFF Concentration of carotenoid pigments per unit volume of the water body [particulate >GF/F phase] by filtration, acetone extraction and spectrophotometry and processed following SCOR protocol
CHLBSSP1 1 Nanograms per litre JHSpec_Chl-b_GFF Concentration of chlorophyll-b {chl-b CAS 519-62-0} per unit volume of the water body [particulate >GF/F phase] by filtration, acetone extraction and trichromatic spectrophotometry following the Jeffrey and Humphrey protocol
CHLCSSP1 1 Nanograms per litre JHSpec_Chl-c_>GFF Concentration of chlorophyll-c {chl-c} per unit volume of the water body [particulate >GF/F phase] by filtration, acetone extraction and trichromatic spectrophotometry following the Jeffrey and Humphrey protocol
CPHLSPP1 1 Milligrams per cubic metre LorSpec_Chl-a_>GFF Concentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >GF/F phase] by filtration, acetone extraction and spectrophotometry and processing following the Lorenzen protocol
CPHLSSP1 1 Milligrams per cubic metre JHSpec_Chl-a_GFF Concentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >GF/F phase] by filtration, acetone extraction and trichromatic spectrophotometry following the Jeffrey and Humphrey protocol
PHAESPP1 1 Milligrams per cubic metre LorSpec_Phae_>GFF Concentration of phaeopigments {pheopigments} per unit volume of the water body [particulate >GF/F phase] by filtration, acetone extraction and spectrophotometry and processing following the Lorenzen protocol
SAMPRFNM 1 Dimensionless SampRef Sample reference number

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.


Bottles may be deployed singly clamped to a wire or in groups of up to 48 on a rosette. Standard bottles have a capacity between 1.7 and 30 L, while Lever Action bottles have a capacity between 1.7 and 12 L. Reversing thermometers may be attached to a spring-loaded disk that rotates through 180° on bottle closure.

Phytoplankton pigment concentration data series for cruise Valdivia VA174

Document History

Converted from CDROM documentation

Data Originator

Paul Tett, Napier University, Edinburgh, UK.

Content of data series

Parameter Unit Parameter code Number of samples Number of stations Comments
Chlorophyll a (Lorenzen) µg l -1 CPHLSPP1 37 8 CTD high standard deviation
Phaeopigment a (Lorenzen) µg l -1 PHAESPP1 37 8 CTD high standard deviation
Chlorophyll a (SCOR) µg l -1 CPHLSSP1 36 8 CTD none
Chlorophyll b (SCOR) ng l -1 CHLBSSP1 36 8 CTD none
Chlorophyll c (SCOR) ng l -1 CHLCSSP1 36 8 CTD none
Carotenoids (SCOR) µg l -1 CAROSSP1 36 8 CTD none

CTD= CTD-Rosette water column sampling station.

Ssampling strategy and methodology

Water samples were collected from 4 to 5 depths using the CTD-rosette water sampler. About 2 litres of seawater were filtered through 47 mm GF/F filters, which were then extracted overnight in buffered 90% acetone. Optical densities (od) were measured against a 90% acetone blank in a Shimadzu UV-1202 spectrophotometer using 50 mm pathlength sub-micro cells. Measurements were made at 750, 665, 664, 647, 630, 510 and 480 nm, and, after addition of 2 drops 1N HCl (od_acid), at 750 and 665 nm. Concentrations of chlorophyll a and phaeopigments were calculated by the Lorenzen method, of chlorophylls a, b and c by the Trichromatic equations (with coefficients of Jeffrey, Humphrey, 1975), and of total carotenoids from the optical densities at 510 and 480 nm.

Lorenzen method:

chlorophyll a (µg l -1 ) = A * K * (od (665) - od_acid (665) ) * E / (V * p)
pheophytin a (µg l -1 ) = A * K * ((R * od_acid (665) - od (665) ) * E / (V * p)


A = Lorenzen coefficient for chlorophyll a (11 µg cm ml -1 )
R = chlorophyll a:pheophytin absorbance at 665 nm (1.7)
K = R / (R - 1)

Trichromatic method (SCOR):

chl. a (mg m-3) = (11.85 * od (664) - 1.54 * od (647) - 0.08 * od (630) ) * E / (V * p)
chl. b (mg m-3) = (-5.43 * od (664) + 21.03 * od (647) - 2.66 * od (630) ) * E / (V * p)
chl. c1+c2 (mg m-3) = (-1.67 * od (664) - 7.60 * od (647) + 24.52 * od (630) ) * E / (V * p)


carotenoids (mg m-3)= (7.6 * (od (480) - 1.49 * od (510) ) * E / (V * p)


E = extract volume (ml)
V = volume of sample water filtered (l)
p = pathlength of cuvette (cm)

BODC processing

In order to standardise parameter units with that held in BODC's database, chlorophyll b and c concentrations were converted from µg l -1 to ng l -1 by multiplying their original values by 1000. The rest of the data were loaded into a database under the ORACLE Relational Database Management System without modification.

Comments on data quality

Measurements suffered from high and somewhat variable blanks, and the standard deviation of replicate chlorophyll a estimated by the Lorenzen method was too high (0.19 mg m -3 ) for these values to be considered reliable. The standard deviations of replicate estimates of chlorophyll a by the Trichromatic method (0.05 µg l -1 ) and of carotenoids (0.06 µg l -1 ) were acceptable.


Jeffrey SW, Humphrey SF (1975) New spectrophotometric equations for determining chlorophylls a, b, c1 and c2 in higher plants, algae and phytoplankton. Biochem. Biophysiol. Planzen, 167, 191-194.

Project Information

PROcesses of Vertical Exchange in Shelf Seas (PROVESS)


PROVESS was an interdisciplinary study of the vertical fluxes of properties through the water column and the surface and bottom boundary layers. The project was funded by the European Community MAST-III programme (MAS3-CT97- 0159) and ran from March 1998 to May 2001.

Scientific Rationale

PROVESS was based on the integration of experimental, theoretical and modelling studies with the aim of improving understanding and quantification of vertical exchange processes in the water column, in particular in the surface and benthic boundary layers and across the> pycnocline. PROVESS also explored mechanisms of physical-biological coupling in which vertical exchanges and turbulence significantly affect the environmental conditions experienced by the biota with particular reference to aggregation, flocculation, sedimentation and trophic interactions.


The experimental phase of the project was carried out at two contrasting sites in the North Sea: the northern North Sea site (NNS) and the southern North Sea site (SNS).

The two sites had the following characteristics:

Position 52° 15.0' N, 4° 17.0' E 59° 20.0' E, 1° 00.0' E
Time of year April-May September-November
Water depth (m) 16 100
M2 max amplitude (m s-1) 0.75 0.15
Max current (m s-1) 1.0 0.6
Delta T (deg C) mixed 7-1
Thermocline depth (m) mixed 35-100
Delta S 1 small
Halocline depth (m) 5-10 cf. thermocline depth
Max wind speed (m s-1) 20 25
Max wave height (m) 5 10
Max wave period (s) 8 10
Internal motion No Yes
Sediment muddy-sand muddy-sand
Biology eutrophic oligotrophic

At both locations measurements were concentrated at a central position with additional measurements being made to estimate horizontal gradients. Moored instruments (including current meters, temperature and pressure sensors, fluorometers, transmissometers, nutrient analysers and meteorological sensors) were deployed between 7 September and 5 November 1998 at the NNS and between 29 March and 25 May 1999 at the SNS. Each experiment was supported by intensive measurement series made from oceanographic ships and involving turbulence dissipation profiler CTD, particle size profilers, optical profilers, benthic sampling and water bottle sampling.

Details of the cruises were as follows:

Site Ship
NNS Valdivia (GER) VA174 5 - 17 Sep 1998
  Dana (DK) D1198 14 - 26 Oct 1998
  Pelagia (NL) PE125 19 - 30 Oct 1998
  Challenger (UK) CH140 22 Oct - 9 Nov 1998
SNS Pelagia (NL) PE135 29 Mar - 9 Apr 1999
  Mitra (NL) MT0499 19 - 30 Apr 1999
  Belgica (BE) BG9912 17 - 21 May 1999

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1998-09-11
End Date (yyyy-mm-dd) Ongoing
Organization Undertaking ActivityAlfred Wegener Institute, Helmholtz Centre for Polar and Marine Research
Country of OrganizationGermany
Originator's Data Activity IdentifierVA174_CTD_076_120
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for VA174_CTD_076_120

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
384027    2.50        6.60    7.50    7.00 Niskin bottle No problem reported    
384028    2.50       28.60   29.60   28.80 Niskin bottle No problem reported    
384029    2.50       50.70   53.20   51.50 Niskin bottle No problem reported    
384030    2.50       92.10   93.30   91.80 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 VLD174 (PROVESS N-1)
Departure Date 1998-09-05
Arrival Date 1998-09-17
Principal Scientist(s)Gunther Krause (Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research)
Ship FS Valdivia

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