Metadata Report for BODC Series Reference Number 1251097


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 Eric Achterberg
Originating Organization University of Southampton School of Ocean and Earth Science
Processing Status banked
Project(s) UKOARP_ThemeB
 

Data Identifiers

Originator's Identifier D366_CTD_NUTS_532:D366046
BODC Series Reference 1251097
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2011-06-27 12:00
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 54.37215 N ( 54° 22.3' N )
Longitude 5.15933 E ( 5° 9.6' E )
Positional Uncertainty Unspecified
Minimum Sensor Depth 1.6 m
Maximum Sensor Depth 35.6 m
Minimum Sensor Height 9.9 m
Maximum Sensor Height 43.9 m
Sea Floor Depth 45.5 m
Sensor Distribution Unspecified -
Sensor Depth Datum Unspecified -
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODE Rank Units Short Title Title
ADEPZZ01 1 Metres DepBelowSurf Depth below surface of the water body
AMONNAKA 1 Micromoles per litre NH4nano_fluor Concentration (nM sensitivity) of ammonium {NH4+ CAS 14798-03-9} per unit volume of the water body [dissolved plus reactive particulate phase] by nanomolar ammonium fluorometry after Kerouel and Aminot (1997)
BOTTFLAG 1 Dimensionless C22_flag Sampling process quality flag (BODC C22)
FIRSEQID 1 Dimensionless FireSeqNo Bottle firing sequence number
ROSPOSID 1 Dimensionless RosPos Bottle rosette position identifier
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

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.

Deployment

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.

D366 ammonium measurements from CTD rosette bottle samples

Originator's Protocol for Data Acquisition and Analysis

Samples for water column measurements of ammonium were taken from the 20 L Niskin bottles deployed on the stainless steel CTD rosette frame. Samples were taken on a daily basis, and all CTD stations were covered. Samples for ammonium were collected in polypropylene vials and reagent added, with subsequent fluorimetric analysis 24 h later. The method by Kerouel and Aminot (1997) was followed, allowing nanomolar ammonium concentrations to be determined. Typically 6-12 depths were covered for a CTD cast.

References Cited

Kerouel, R. and Aminot, A. (1997). Fluorometric determination of ammonia in sea and estuarine waters by direct segmented flow analysis. Marine Chemistry, 57, 265-275.

BODC Data Processing Procedures

Data were submitted after the cruise and archived under BODC's accession number USO130151. The ammonium data were provided in a file with sample metadata (station, cast number, date and depth). The data were matched to the metadata in the database based on cast/depth combinations. A number of discrepancies were discovered and queried with the originator. A revised data file was received with these discrepancies resolved. In addition there was a corrected version of data for cast 68.

No unit conversion was necessary as the data were provided in equivalent units to the assigned BODC parameter code. The data were loaded to the database using established BODC procedures.

A parameter mapping table is provided below;

Originator's Parameter Units Description BODC Parameter Code Units Comments
Ammonium concentration nmol l -1 Concentration (nM sensitivity) of ammonium {NH4} per unit volume of the water body [dissolved plus reactive particulate phase] by nanomolar ammonium fluorometry after Kerouel and Aminot (1997) AMONNAKA umol l -1 Unit conversion /1000 applied. Nano-molar data represented in micro-molar units are valid to the fourth decimal place

Data Quality Report

No data quality issues were reported. The cast 74 depth 20m data value was flagged suspect as it was much lower than the other values from surrounding depths from cast 74.

Problem Report

Not relevant to this data set.


Project Information

UKOARP Theme B: Ocean acidification impacts on sea surface biology, biogeochemistry and climate

The overall aim of this theme is to obtain a quantitative understanding of the impact of ocean acidification (OA) on the surface ocean biology and ecosystem and on the role of the surface ocean within the overall Earth System.

The aims of the theme are:

The main consortium activities will consist of in-situ measurements on three dedicated cruises, as well as on-deck bioassay experiments probing the response of the in-situ community to elevated CO2. Most of the planned work will be carried out on the three cruises to locations with strong gradients in seawater carbon chemistry and pH; the Arctic Ocean, around the British Isles and the Southern Ocean.

Weblink: http://www.oceanacidification.org.uk/research_programme/surface_ocean.aspx


Data Activity or Cruise Information

Cruise

Cruise Name D366 (D367)
Departure Date 2011-06-06
Arrival Date 2011-07-09
Principal Scientist(s)Eric Pieter Achterberg (University of Southampton School of Ocean and Earth Science)
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