Metadata Report for BODC Series Reference Number 1340691

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

Data Description

Data Category

Water sample data

Instrument Type

Name	Categories
Niskin bottle	discrete water samplers

Instrument Mounting

lowered unmanned submersible

Originating Country

United Kingdom

Originator

Ms Amanda Beesley

Originating Organization

Plymouth Marine Laboratory

Processing Status

banked

Online delivery of data

Download available - Ocean Data View (ODV) format

Project(s)

Oceans 2025 Theme 10 SO1:AMT

Data Identifiers

Originator's Identifier	D371_CTD_NUTS_861:CTD031
BODC Series Reference	1340691

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm)	2011-10-15 06:04
End Time (yyyy-mm-dd hh:mm)	-
Nominal Cycle Interval	-

Spatial Co-ordinates

Latitude	16.48346 N ( 16° 29.0' N )
Longitude	35.74334 W ( 35° 44.6' W )
Positional Uncertainty	Unspecified
Minimum Sensor or Sampling Depth	2.9 m
Maximum Sensor or Sampling Depth	1000.8 m
Minimum Sensor or Sampling Height	3819.9 m
Maximum Sensor or Sampling Height	4817.8 m
Sea Floor Depth	4820.7 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 CODE	Rank	Units	Title
ADEPZZ01	1	Metres	Depth (spatial coordinate) relative to water surface in the water body
BOTTFLAG	1	Not applicable	Sampling process quality flag (BODC C22)
FIRSEQID	1	Dimensionless	Bottle firing sequence number
NTRIAATX	1	Micromoles per litre	Concentration of nitrite {NO2- CAS 14797-65-0} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
NTRZAATX	1	Micromoles per litre	Concentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
PHOSAATX	1	Micromoles per litre	Concentration of phosphate {PO43- CAS 14265-44-2} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis
ROSPOSID	1	Dimensionless	Bottle rosette position identifier
SAMPRFNM	1	Dimensionless	Sample reference number
SLCAAATX	1	Micromoles per litre	Concentration 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

BOTTFLAG	Definition
0	The sampling event occurred without any incident being reported to BODC.
1	The filter in an in-situ sampling pump physically ruptured during sample resulting in an unquantifiable loss of sampled material.
2	Analytical 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.
3	The 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.
4	During 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.
5	Water was reported to be escaping from the bottle as the rosette was being recovered.
6	The bottle seals were observed to be incorrectly seated and the bottle was only part full of water on recovery.
7	Either 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).
8	There is reason to doubt the accuracy of the sampling depth associated with the sample.
9	The 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.

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.

AMT21 (D371) Micro-molar nutrient measurements from CTD bottle samples

Originator's Protocol for Data Acquisition and Analysis

Water samples were taken from the Sea-Bird CTD rosette system. They were sub-sampled into acid-clean 60 ml HDPE (nalgene) sample bottles. Analysis for nutrients was completed within 1-2 hours of sampling in all cases. Clean handling techniques were employed to avoid contamination of the samples.

The main nutrient analyser was a 5-channel Bran and Luebbe AAIII segmented flow autoanalyser. The analytical chemical methodologies used were according to Brewer and Riley (1965) for nitrate, Grasshoff (1976) for nitrite and Kirkwood (1989) for phosphate and silicate.

References Cited

Brewer P.G. and Riley J.P., 1965. The automatic determination of nitrate in sea water. Deep-Sea Research, 12, 765-772.

Grasshoff K., 1976. Methods of seawater analysis. Verlag Chemie, Weiheim: 317 pp.

Kirkwood D.S., 1989. Simultaneous determination of selected nutrients in seawater. ICES CM1989/C:29, 12pp.

Instrumentation Description

5-channel Bran and Luebbe AAIII segmented flow autoanalyser

BODC Data Processing Procedures

Data were submitted to BODC in Microsoft Excel spreadsheet format and saved to the BODC archive with reference PML130010. Sample metadata provided (Cast number, niskin bottle number and sample depth) were checked against information held in the database. There were a few minor depth discrepancies that were resolved through correspondence with the originator.

No unit conversions were necessary as the units provided matched the units for the parameter codes in the BODC Parameter Dictionary. The dataset was loaded to the database following BODC protocols.

A parameter mapping table is provided below;

Originator's Parameter	Units	Description	BODC Parameter Code	Units	Comments
Nitrate+Nitrite	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	-
Nitrite	µmol l^-1	Concentration of nitrite {NO₂} per unit volume of the water body [dissolved plus reactive particulate phase] by colorimetric autoanalysis	NTRIAATX	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	-
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	-

Data Quality Report

Data provided were quality checked by the originator and flagged accordingly. The nutrients supplied from cast CTD002 were flagged as the originator suspected the sample order had become mixed up and there was no way to confirm what should be the correct order.

Measurement precision information from data originators: quantities flagged as below detection by the originators have been given the value of the limit of detection and flagged appropriately in the BODC database.

Problem Report

Not applicable for this dataset.

Project Information

Oceans 2025 Theme 10, Sustained Observation Activity 1: The Atlantic Meridional Transect (AMT)

The Atlantic Meridional Transect has been operational since 1995 and through the Oceans 2025 programme secures funding for a further five cruises during the period 2007-2012. The AMT programme began in 1995 utilising the passage of the RRS James Clark Ross between the UK and the Falkland Islands southwards in September and northwards in April each year. Prior to Oceans 2025 the AMT programme has completed 18 cruises following this transect in the Atlantic Ocean. This sustained observing system aims to provide basin-scale understanding of the distribution of planktonic communities, their nutrient turnover and biogenic export in the context of hydrographic and biogeochemical provinces of the North and South Atlantic Oceans.

The Atlantic Meridional Transect Programme is an open ocean in situ observing system that will:

give early warning of any fundamental change in Atlantic ecosystem functionng
improve forecasts of the future ocean state and associated socio-economic impacts
provide a "contextual" logistical and scientific infrastructure for independently-funded national and international open ocean biogeochemical and ecological research.

The specific objectives are:

To collect hydrographic, chemical, ecological and optical data on transects between the UK and the Falkland Islands
To quantify the nature and causes of ecological and biogeochemical variability in planktonic ecosystems
To assess the effects of variability in planktonic ecosystems on biogenic export and on air-sea exchange of radiatively active gases

The measurements taken and experiments carried out on the AMT cruises will be closely linked to Themes 2 and 5. The planned cruise track also allows for the AMT data to be used in providing spatial context to the Sustained Observation Activities at the Porcupine Abyssal Plain Ocean Observatory (SO2) and the Western Channel Observatory (SO10).

More detailed information on this Work Package is available at pages 6 - 9 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10

Weblink: http://www.oceans2025.org/

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd)	2011-10-15
End Date (yyyy-mm-dd)	2011-10-15
Organization Undertaking Activity	Plymouth Marine Laboratory
Country of Organization	United Kingdom
Originator's Data Activity Identifier	D371_CTD_CTD031
Platform Category	lowered unmanned submersible

BODC Sample Metadata Report for D371_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

618323	20.00	1	1	1009.80	1010.10	1000.80	Niskin bottle	No problem reported
618326	20.00	2	2	303.00	303.90	300.70	Niskin bottle	No problem reported
618329	20.00	3	3	202.30	202.80	200.50	Niskin bottle	No problem reported
618332	20.00	4	4	162.50	163.00	161.00	Niskin bottle	No problem reported
618335	20.00	5	5	129.70	130.20	128.40	Niskin bottle	No problem reported
618338	20.00	6	6	109.40	109.90	108.30	Niskin bottle	No problem reported
618341	20.00	7	7	109.20	109.90	108.20	Niskin bottle	No problem reported
618344	20.00	8	8	108.90	110.20	108.20	Niskin bottle	No problem reported
618347	20.00	9	9	109.50	109.90	108.30	Niskin bottle	No problem reported
618350	20.00	10	10	92.20	92.50	91.10	Niskin bottle	No problem reported
618353	20.00	11	11	77.10	77.60	76.20	Niskin bottle	No problem reported
618356	20.00	12	12	64.10	64.30	63.10	Niskin bottle	No problem reported
618359	20.00	13	13	64.10	64.40	63.10	Niskin bottle	No problem reported
618362	20.00	14	14	48.00	48.40	47.20	Niskin bottle	No problem reported
618365	20.00	15	15	48.00	48.30	47.10	Niskin bottle	No problem reported
618368	20.00	16	16	27.90	28.20	27.20	Niskin bottle	No problem reported
618371	20.00	17	17	28.00	28.40	27.30	Niskin bottle	No problem reported
618374	20.00	18	18	21.60	21.80	20.90	Niskin bottle	No problem reported
618377	20.00	19	19	15.70	16.10	15.10	Niskin bottle	No problem reported
618380	20.00	20	20	15.60	16.00	15.00	Niskin bottle	No problem reported
618383	20.00	21	21	3.70	4.00	3.10	Niskin bottle	No problem reported
618386	20.00	22	22	3.30	4.00	2.90	Niskin bottle	No problem reported
618389	20.00	23	23	3.70	4.10	3.20	Niskin bottle	No problem reported
618392	20.00	24	24	3.30	4.10	3.00	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	D371 (AMT21)
Departure Date	2011-09-29
Arrival Date	2011-11-13
Principal Scientist(s)	Glen A Tarran (Plymouth Marine Laboratory)
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