Metadata Report for BODC Series Reference Number 2134447

• 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

Marianda Versatile INstrument for the Determination of Total inorganic carbon and titration Alkalinity (VINDTA) 3C

The VINDTA 3C (Versatile INstrument for the Determination of Total inorganic carbon and titration Alkalinity) is a laboratory alkalinity titration system combined with an extraction unit for coulometric titration, which simultaneously determines the alkalinity and dissolved inorganic carbon content of a sample. The sample transport is performed with peristaltic pumps and acid is added to the sample using a membrane pump. No pressurizing system is required and only one gas supply (nitrogen or dry and CO2-free air) is necessary. The system uses a Metrohm Titrino 719S, an ORION-Ross pH electrode and a Metrohm reference electrode. The burette, the pipette and the analysis cell have a water jacket around them. Precision is typically ± 1 µmol kg^-1 for TA and/or DIC in open ocean water.

Further details can be found in the manufacturer's brochure.

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.

D321A Dissolved Inorganic Carbon (DIC) and Total Alkalinity (TA) samples from CTD bottles

Originator's Protocol for Data Acquisition and Analysis

This dataset comprises Dissolved Inorganic Carbon (DIC) and Total Alkalinity (TA) measurements made on 136 discrete water samples collected from 15 CTD casts during Cruise D321A, in the Iceland Basin.

Sampling strategy:

The sampling procedure used for the determination of Dissolved Inorganic Carbon and Total Alkalinity was according to DOE (1994). Samples were taken as soon as possible after the Niskin bottle was opened (following oxygen samples) to prevent any gas exchange of the sample with the head space of the bottle. A piece of silicone tubing was used for the sampling and care was taken to prevent any air bubbles being trapped in the sample. The sample was stored in a borosilicate glass bottle (250 mL), which was rinsed once with the sample in order to remove trace of the previous sample. The tubing was inserted at the bottom of the bottle which was then filled and water was left to overflow by at least half a bottle volume. The glass stopper was inserted in the bottle in order to remove the stopper volume and a head space of 1% (2.5 mL) was allowed for water expansion. s

The sample was then poisoned with a saturated solution of mercuric chloride (7 g/100 mL) in a 0.02% volume ratio (50 uL) in order to prevent any biological activity in the stored sample. The bottle was air- tight sealed with a glass stopper and shaken to mix the mercuric chloride homogeneously. Samples were stored in a cool and dark place until analysis. DIC samples were generally analysed within less than 2 days after sampling and water for alkalinity measurements was stored for analysis back at NOC.

Instrumentation and analysis methods:

DIC determination:

All the DIC samples were analysed using a coulometric titration. The instrument used for this purpose was the VINDTA 3C (Figure 27) from Marianda (Kiel, Germany) connected with a coulometer (UIC). Repeated measurements on the same batch of seawater (n > or = 3) were run every day of analysis, prior to the sample analysis, in order to assess the precision of the method. The standard deviation of the sub-samples analysed ranged between 0.04% and 0.09%, with a mean value of 0.07% for the whole cruise (less than 2 umol kg-1), which is well within the expected value of less than 0.1% (Bates et al., 1996 ; Johnson et al., 1998). Certified Reference Materials (CRMs) from A.G. Dickson (Scripps Institution of Oceanography) were used as standards to calibrate the system at the beginning of each day of analysis. A correction factor was applied to all measured values according to Millero et al., (1998) in order to normalize the measured values :

DIC(corr.)=DIC(meas.) x (CRMcert/ CRMmeas.)

where CRMcert is the certified value for the specific batch of CRMs used.

The sample is acidified with phosphoric acid 10% which results in the conversion of total dissolved inorganic carbon ( [CO2*] + [HCO3-] + [CO32-] ; where [CO2*] = [CO2] + [H2CO3]) to CO2 gas. The CO2 generated is carried into the coulometric cell using an inert gas (N2) and titrated coulometrically.

The coulometric cell is composed of two half cells : anode and cathode. The cathode cell contains mono-ethanolamine, a colorimetric pH indicator (Thymol blue) and a platinum electrode, whereas the anode cell is composed of a silver electrode and contains an anode solution saturated with potassium iodide crystals. The CO2 purged causes the indicator to fade and the percentage of transmission (%T) to increase, and the titration current is automatically activated. The final titration point is determined spectrophotometrically when the final transmittance of the solution is kept at a constant value (29%T).

Total Alkalinity determination:

The TA measurements at sea failed because of software and communication problem between the computer and the titration unit. After determination of DIC concentration, samples were well sealed and kept for TA analysis back to NOCS.

For the determination of TA, the sample of seawater is titrated with hydrochloric acid 0.1 mol L-1. The acid solution is added in small increments until the carbonic acid equivalence point is reached (protonation of carbonate and bicarbonate ions). The total volume added allows the calculation of total alkalinity to be undertaken. A glass electrode/reference electrode system monitors the titration (measurement of the electromotive force).

Instrumentation Description

Stainless steel CTD: Seabird 911+ fitted with Seabird carousel type SBE32 and 24 x 20 L Niskin bottles.

Titanium CTD: Seabird 911 + CTD fitted with SBE 32 carousel and 24 x 10 L trace metal Niskin bottles. Samples from both the titanium and stainless steel CTDs were analysed.

VINDTA 3C from Marianda (Kiel, Germany) connected to a coulometer (UIC).

BODC Data Processing Procedures

Data received were loaded into the BODC database using established BODC data banking procedures. A reformatted version of the originator's data file was saved under L:\users\odb\d321a\bottles\DIC in 2 formats: DIC_TA_reformat.csv and DIC_TA_reformat.xls

The file was supplemented with the following headings:

• OID
• DEPTH
• ROSPOS
• TCO2KG01
• TCO2KG01_F
• MDMAP014
• MDMAP014_F
• CRUISE

In the originator's file, most samples had 'Bottle number' recorded. This was taken to be equivalent to ROSPOS. Where a sample had no bottle no., entries in EVENT and BOTTLE were examined to find the ROSPOS for that particular depth. In several instances, more than 1 bottle had been fired at a particular depth so for consistency, it was decided that where multiple bottles had been fired at a single depth, the lowest numbered bottle (=lowest ROSPOS) would be assigned to the sample at that depth. There were 2 instances of duplicate analyses from the same CTD bottle (OID=16286A, BEN=722860 in both cases and IBTTLE=178538 and 178339) and the 2 values for DIC and TA were averaged for both duplicate sets.

The originator's parameters are mapped to BODC parameters as below:

Data Quality Report

No additional information on data quality supplied by originator.

Problem Report

For two samples, comments were recorded by the originator, as below:

• OID IBTTLE COMMENT
• 16222A 179325 Bottle did not close properly
• 16226A 179255 Bottle did not close properly

Project Information

Oceans 2025 - The NERC Marine Centres' Strategic Research Programme 2007-2012

Who funds the programme?

The Natural Environment Research Council (NERC) funds the Oceans 2025 programme, which was originally planned in the context of NERC's 2002-2007 strategy and later realigned to NERC's subsequent strategy (Next Generation Science for Planet Earth; NERC 2007).

Who is involved in the programme?

The Oceans 2025 programme was designed by and is to be implemented through seven leading UK marine centres. The marine centres work together in coordination and are also supported by cooperation and input from government bodies, universities and other partners. The seven marine centres are:

• National Oceanography Centre, Southampton (NOCS)
• Plymouth Marine Laboratory (PML)
• Marine Biological Association (MBA)
• Sir Alister Hardy Foundation for Marine Science (SAHFOS)
• Proudman Oceanographic Laboratory (POL)
• Scottish Association for Marine Science (SAMS)
• Sea Mammal Research Unit (SMRU)

Oceans2025 provides funding to three national marine facilities, which provide services to the wider UK marine community, in addition to the Oceans 2025 community. These facilities are:

• British Oceanographic Data Centre (BODC), hosted at POL
• Permanent Service for Mean Sea Level (PSMSL), hosted at POL
• Culture Collection of Algae and Protozoa (CCAP), hosted at SAMS

The NERC-run Strategic Ocean Funding Initiative (SOFI) provides additional support to the programme by funding additional research projects and studentships that closely complement the Oceans 2025 programme, primarily through universities.

What is the programme about?

Oceans 2025 sets out to address some key challenges that face the UK as a result of a changing marine environment. The research funded through the programme sets out to increase understanding of the size, nature and impacts of these changes, with the aim to:

• improve knowledge of how the seas behave, not just now but in the future;
• help assess what that might mean for the Earth system and for society;
• assist in developing sustainable solutions for the management of marine resources for future generations;
• enhance the research capabilities and facilities available for UK marine science.

In order to address these aims there are nine science themes supported by the Oceans 2025 programme:

• Climate, circulation and sea level (Theme 1)
• Marine biogeochemical cycles (Theme 2)
• Shelf and coastal processes (Theme 3)
• Biodiversity and ecosystem functioning (Theme 4)
• Continental margins and deep ocean (Theme 5)
• Sustainable marine resources (Theme 6)
• Technology development (Theme 8)
• Next generation ocean prediction (Theme 9)
• Integration of sustained observations in the marine environment (Theme 10)

In the original programme proposal there was a theme on health and human impacts (Theme 7). The elements of this Theme have subsequently been included in Themes 3 and 9.

When is the programme active?

The programme started in April 2007 with funding for 5 years.

Brief summary of the programme fieldwork/data

Programme fieldwork and data collection are to be achieved through:

• physical, biological and chemical parameters sampling throughout the North and South Atlantic during collaborative research cruises aboard NERC's research vessels RRS Discovery, RRS James Cook and RRS James Clark Ross;
• the Continuous Plankton Recorder being deployed by SAHFOS in the North Atlantic and North Pacific on 'ships of opportunity';
• physical parameters measured and relayed in near real-time by fixed moorings and ARGO floats;
• coastal and shelf sea observatory data (Liverpool Bay Coastal Observatory (LBCO) and Western Channel Observatory (WCO)) using the RV Prince Madog and RV Quest.

The data is to be fed into models for validation and future projections. Greater detail can be found in the Theme documents.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for D321A_CTD_16243A

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: D321A_CTD_16243A

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