Metadata Report for BODC Series Reference Number 2134527

• 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.

Non-toxic (underway) sea water supply

A source of uncontaminated near-surface (commonly 3 to 7 m) seawater pumped continuously to shipboard laboratories on research vessels. There is typically a temperature sensor near the intake (known as the hull temperature) to provide measurements that are as close as possible to the ambient water temperature. The flow from the supply is typically directed through continuously logged sensors such as a thermosalinograph and a fluorometer. Water samples are often collected from the non-toxic supply. The system is also referred to as the underway supply.

Cruise D321A Total Alkalinity (TA) samples from Underway samples

Originators Acquisition and Analysis

This dataset comprises Total Alkalinity (TA) measurements made on 76 water samples collected from the non-toxic underway water supply, during Cruise D321A, in the Iceland Basin. One sample provided no measurement, so there are 75 processed samples in this dataset.

Sampling Strategy

The sampling procedure used for the determination of Total Alkalinity was according to DOE (1994). During the cruise, underway samples were taken from the non-toxic seawater supply (intake at ~5m depth) in order to obtain a good surface coverage of the survey region. The position and time of each sampling point were carefully recorded. Samples were stored in a cool dark place until analysis. DIC samples were generally analysed within less than 2 days after sampling.

All the samples were analysed using a coulometric titration. The instrument used for this purpose was the VINDTA 3C from Marianda (Kiel, Germany) connected with a coulometer (UIC).

The sample was stored in a borosilicate glass bottle (250mL), 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 headspace of 1% (2.5mL) was allowed for water expansion.

The sample was then poisoned with a saturated solution of mercuric chloride (7g/100mL) in a 0.02% volume ratio (50µl) in order to prevent any biological activity in the stored sample. The bottle was airtight sealed with a glass stopper and shaken to mix the mercuric chloride homogeneously. Water for alkalinity measurements was stored for analysis in a cool and dark place back at NOC.

Instrumentation and analysis methods

The Total Alkalinity 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 at NOCS.

A known amount of seawater is placed in a closed cell where it is titrated with a solution of hydrochloric acid. The acid is made up in a sodium chloride background to approximate the ionic strength of seawater, so as to maintain activity coefficients approximately constant during the titration. The use of a closed cell allows the subsequent data evaluation to assume that the total dissolved inorganic carbon remains constant throughout the titration apart from the effect of dilution.

The progress of the titration is monitored using a glass electrode/reference electrode pH cell.

BODC Processing

Data received were loaded into the BODC database using established BODC data banking procedures.

There was one case of absent data so that entry was dropped.

Data Quality Report

No additional information on data quality supplied by originator.

Cruise D321a Dissolved Inorganic Carbon Sampling Document

Originator's Protocol for Data Acquisition and Analysis

This dataset comprises Dissolved Inorganic Carbon (DIC) measurements made on 75 discrete underway samples from the surface water pump 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). During the cruise, underway samples were taken from the non-toxic seawater supply (intake at ~5m depth) along with nutrients, chlorophyll and SEM samples in order to obtain a good surface coverage of the survey region. The position and time of each sampling point were carefully recorded. Samples were stored in a cool and dark place until analysis. DIC samples were generally analysed within less than 2 days after sampling.

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 (250mL), 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% (2.5mL)was allowed for water expansion.

The sample was then poisoned with a saturated solution of mercuric chloride (7g/100mL) in a 0.02% volume ratio (50uL) 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.

Instrumentation and Analysis Methods

All the DIC samples were analysed using a coulometric titration. The instrument used for this purpose was the VINDTA 3C from Marianda (kiel, Germany) connected with a coulometer (UIC). Repeated measurements on the same batch of seawater were run every day of analysis, prior to the sample analysis, in order to assess the precision of the method. 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. The system was calibrated 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 normalise 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).

References Cited

Allen J.T. et al., 2008.Cruise Report No. 23 RRS Discovery Cruise 321 24 JUL- 23 AUG 2007; Dickson A.G., Goyet C., eds ORNL/CDIAC-74, DOE (u.s. Department of Energy) (1994) Handbook for the analysis of the various parameters of the carbon dioxide system in sea water; Version 2.; Millero F.J. et al., 1998. Assessment of the quality of the shipboard measurements of total alkalinity on the WOCE Hydrography program, Indian Ocean CO2 survey cruises 1994-1996. Marine Chemistry, 639-20.

Instrumentation Description

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

BODC Data Processing Procedures

Data arrived at BODC in excel format files. These were archived both in Excel .xls and Comma Separated Value files (.csv) Data received were loaded into the BODC database using established BODC data banking procedures, without any changes.

• Station number was converted to the BODC identification
• Parameter TCO2KG01 was applied to the Dissolved Inorganic Carbon values, this is described as: Concentration of carbon (total inorganic) {TCO2} per unit mass of the water body [dissolved plus reactive particulate phase] by colourmetry. uMol/Kg this matches the originators data, so no changes were required.
• Absent data values were removed

Data loaded into BODC's database without any changes.

Bathymetry data was used for depth data where available, but OID values AC-UW15, and AC-UW77-82 used GEBCO data as the difference between the two wasn't particularly large, and there was no bathymetry data available for these events.

A parameter mapping table is provided below;

Data Quality Report

No additional information on data quality supplied by originator.

Problem Report

All data looked plausible and remained unflagged. The data were checked for values outside the parameter code limits using sql queries. All values appeared reasonable.

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

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: