Metadata Report for BODC Series Reference Number 2110666

• 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

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.

If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:

"Contains public sector information licensed under the Open Government Licence v1.0."

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.

Dissolved Inorganic Carbon (DIC, TCO₂) and Total Alkalinity (TA) discrete samples from CTD bottles during RRS James Cook cruise 71

Originator's Protocol for Data Acquisition and Analysis

Sampling Strategy

Samples were collected at up to 12 depth levels at 7 CTD stations.

Sampling Method

Samples were collected from 10L CTD Niskin bottles into special ground glass topped glass bottles using a small length of narrow bore tubing inserted into the bottom of the bottle. Care was taken to ensure that no gas bubbles were present in the sample by first inverting the bottle and revolving it slowly while returning it to an upright position. Once filled the bottle was flushed from the bottom with three times its volume before inserting the glass stopper. The sample was then opened in a fume hood and 2.5 mL of seawater removed and 50 µL of mercuric chloride added by gently placing the pipette tip below the surface and expelling the liquid. A small amount of silicone grease was placed on the stopper before it was replaced and sealed into the bottle with tape.

TCO₂ Analysis Method

The analysis of DIC was undertaken in National Oceanography Centre, Southampton using VINDTA 3C (Marianda, Germany, unit 11 and unit 24). By reaction with phosphoric acid, dissolved inorganic carbon of the sample was converted to CO₂. The CO₂ gas was carried by N₂ into the coulometer cell and reacts with monoethanolamine to form a titratable acid which causes the fading of the blue indicator. Responding to the colour change, a current flow generates base to remove the acid and restore the indicator to the original colour. The amount of CO₂ can be estimated from the required coulombs of the current required (corrected for blank), and DIC concentration can then be calculated given the known sample volume.

Standardization Technique

In order to standardize the results, Certified Reference Materials (CRM) from A.G. Dickson, Scripps Institution of Oceanography were analysed as standards to calibrate the instrument at the beginning and end of each day of analysis. A daily correction factor was applied to all measured values according to Millero et al. (1998).

Sample Volume

19.1681 mL

Field Replicate Info

Repeated measurements on the same batch of seawater (n>=3) in the lab gave consistent results (precision for the whole dataset estimated as 2.0±0.7 µmol kg^-1).

Poisoning Correction Description:

Saturated HgCl₂ (0.05 mL) is added to the collected sample to prevent the sample from biological modification. Since we use a large sampling volume (250 mL), the dilution effect of adding HgCl₂ is neglectable (0.02 %).

Poison Volume:

0.05 mL

Accuracy Info:

Repeated measurements on the same batch of seawater (n>=3) were undertaken every day prior to sample analysis in order to assess the precision of the method. The precision was estimated for the whole dataset to be 2.0±0.7 µmol kg^-1 for DIC and 1.2±0.5 µmol kg^-1 for TA. The accuracy of the measurement is assured by the standardization using the CRM from A.G. Dickson, Scripps Institution of Oceanography on daily basis.

Alkalinity (TA) Analysis method

Alkalinity was resolved using the non-linear curve fitting (least-squares) approach of Dickson et al. (2007).

Type of Tritration

Titration with HCl (~0.10 mol L^-1) uses a closed cell procedure with an open cell, with a pH half cell electrode (glass bodied Orion 8101SC Ross, USA) and an Ag/AgCl reference electrode (model 6.0729.100, Metrohm, Switzerland).

Cell Type

open cell

Sample Volume

97.409 mL

Accuracy Info

Repeated measurements on the same batch of seawater (n>=3) were undertaken every day prior to sample analysis in order to assess the precision of the method. The precision was estimated for the whole dataset to be 2.0±0.7 µmol kg^-1 for DIC and 1.2±0.5 µmol kg^-1 for TA. The accuracy of the measurement is assured by the standardization using the CRM from A.G. Dickson, Scripps Institution of Oceanography on daily basis.

References

Dickson A.G., Sabine C.L., and Christian J.R., 2007. Guide to best practices for ocean CO₂ measurements. PICES Special Publication 3, 191 pp.

Hartman S.E., Dumousseaud C. and Roberts A., 2011 Operating manual for the Marianda (Versatile INstrument for the Determination of Titration Alkalinity) VINDTA 3C for the laboratory based determination of Total Alkalinity and Total Dissolved Inorganic Carbon in seawater. Southampton, UK, National Oceanography Centre, 66 pp. (National Oceanography Centre Internal Document, 01).

BODC Data Processing Procedures

The data arrived at BODC in one Excel (.xls) file containing discrete samples collected from the underway non-toxic supply and CTD deployments. Data received were loaded into the BODC database using established BODC data banking procedures. Data were loaded into BODC's database without any changes. Originator's variables were mapped to appropriate BODC parameter codes as follows:

Data Quality Report

None (BODC assessment)

Problem Report

None (BODC assessment)

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

No Document Information Held for the Series

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: JC071_CTD_JC071-019-3

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