Metadata Report for BODC Series Reference Number 1346232

• 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

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.

Inorganic nutrients concentrations (micromolar sensitivity nitrate plus nitrite, phosphate and silicate) for UK SOLAS cruise Discovery D326

Originator's Protocol for Data Acquisition and Analysis

Samples for inorganic nutrient analyses were drawn from Niskin bottles deployed on the CTD rosette frame, and from the ship's non-toxic pumped water supply. Samples were taken in 25 ml sterilin coulter counter vials, and refrigerated at 4 degree C prior to analysis, which took place within 24 hours. Analysis for nitrate plus nitrite, phosphate and silicate was undertaken on a Skalar San Plus autoanalyser following methods described by Kirkwood (1994), with the exception that the pump rates through the phosphate line were increased by a factor of 1.5 to improve reproducibility and peak shape. Lines were washed daily with 0.5 M sodium hydroxide and 10% Decon (N, Si). Wash time and sample time were 90 seconds. Lines were flooded with Decon for transit. A single set of mixed standards were made up by diluting 5 mM solutions made from weighed dried salts in 1 L of ASW into plastic 1 L volumetric.
Data processing was undertaken using Skalar proprietary software. Time series of baseline, instrument sensitivity, calibration curve correlation coefficient, nitrate reduction efficiency and duplicate difference were compiled and updated on a daily basis.
More information about the performance of the autoanalyser can be obtained from the cruise report.

References Cited

Kirkwood D.S., 1994. Nutrients: Practical notes on their determination in seawater. ICES Techniques in Marine Environmental Sciences report 17. International Council for the Exploration of the Seas, Copenhagen, 25 pp.

BODC Data Processing Procedures

Data were received by BODC in Microsoft Excel spreadsheet format as part of the underway and CTD samples data compendium files compiled by Micha Rijkenberg and containing the nutrient data plus other parameters measured by various project participants.

CTD data were identified using CTD cast number, bottle number and bottle firing depth. Underway data were identified using samples identifiers and sampling date and time. No discrepancies were found between the source files and existing records in BODC database.

In four instances samples were present in duplicate. If both values were flagged as above the limit of detection by the originator the values were averaged and the standard deviation calculated prior to loading in the database. If one value was below the LOD and the other value above then only the value above LOD was loaded to the database. No standard deviation was derived if both values were below LOD.

Parameter codes defined in BODC parameter dictionary were assigned to the variables as follows:

The data were then banked according to BODC standard procedures for sample data.

Data Quality Report

One silicate value (NT83, 16/01/2008 11:00) was clearly out of range and has been flagged suspect in the database.

The following information was provided by the originator:

The limits of detection were defined as twice the level of background noise averaged out over the course of the cruise. These were 0.28 µM for the nitrate+nitrite line, 0.06 µM for the silicate line and 0.04 µM for the phosphate line.

The error on the data were as follows: 1.20% for nitrate+nitrite concentrations, 1.48% for silicate concentrations and 1.79% for phosphate concentration.

Project Information

UK Surface Ocean Lower Atmosphere Study

The UK Surface Ocean Lower Atmosphere Study (UK SOLAS) is the UK's contribution to the international SOLAS programme.

UK SOLAS formed interdisciplinary teams to address three primary aims

• To determine the mechanisms controlling rates of chemical transfer and improve estimates of chemical exchanges
• To evaluate the impact of these exchanges on the biogeochemistry of the surface ocean and lower atmosphere and on feedbacks between the ocean and atmosphere
• To quantify the impacts of these boundary layer processes on the global climate system

UK SOLAS started in 2003, to run for seven years. The programme was funded by the Natural Environment Research Council.

Funded projects

In total, 19 projects have been funded by UK SOLAS, over four funding rounds.

UK SOLAS has also supported ten tied studentships, and two CASE studentships.

Fieldwork

UK SOLAS fieldwork has included eight dedicated research cruises in the North Atlantic Ocean. Continuous measurements were made aboard aboard the Norwegian weather ship, Polarfront, until her decommission in 2009. Time series have been established at the SOLAS Cape Verde Observatory, and at the Plymouth Marine Laboratory L4 station. Experiments have taken place at the Bergen mesocosm facility.

A series of collaborative aircraft campaigns have added complementary atmospheric data. These campaigns were funded by UK SOLAS, African Monsoon Multidisciplinary Analyses (AMMA-UK), Dust and Biomass Experiment (DABEX) and the Facility for Airborne Atmospheric Measurements (FAAM).

Weblink: http://www.nerc.ac.uk/research/programmes/solas/

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for D326_CTD_16407B

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

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:

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Appendix 1: D326_CTD_16407B

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.