Metadata Report for BODC Series Reference Number 2308639

• 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

Data access conditions (generic)

Access to these data is currently restricted and the data may not be released by BODC without obtaining specific permission from the data originator.

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.

Scripps Institution of Oceanography total alkalinity titration system

A laboratory titration system designed to measure the total alkalinity of discrete seawater samples. The system is based on the Metrohm 876 Dosimat Plus, with a calibrated 5 ml exchange unit. It also uses an Agilent 34970A Data Acquisition/Data Logger Switch Unit with a custom-made unity gain amplifier. The recommended pH electrode is the Metrohm Ecotrode Plus. The system uses a potentiometric titration method: The sample is acidified to a pH of 3.6. The evolved CO2 is removed, and the titration continues to a pH of 3. The equivalence point corresponding to the total alkalinity is evaluated from titration points in the pH region 3.0 to 3.5 using a non-linear least-squares procedure. This corrects for the reactions with sulfate and fluoride ions present in the seawater. The system includes a desktop computer with LabVIEW 2013 software. Recommended titration temperature is 20 degC. Sample volume is 125 ml. Initial start-up takes approximately 1 hour, with a measurement throughput of 4 - 6 per hour. Power line frequency is 60 Hz.

For more information, please see this document: https://www.bodc.ac.uk/data/documents/nodb/pdf/Scripps-TA-Titration-System_Brochure.pdf

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.

CTD bottle dissolved inorganic carbon and total alkalinity data from RRS James Cook Cruise JC278

Acquisition description:

Sampling methodology

Dissolved inorganic carbon (DIC) and total alkalinity (TA) data were taken from 17 stainless steel CTD (Conductivity, Temperature, Depth) casts during the RRS James Cook cruise 278 (JC278), between the 30th of May 2025 to 23rd June 2025, at the Porcupine Abyssal Plain - Sustained Observatory (PAP-SO) site in the North East Atlantic ocean. An NMF (National Marine Facilities) 24-way Stainless Steel CTD frame was used with 20 litre Niskin water samplers. Samples were collected from the Niskin bottles in 250 millilitre borosilicate glass bottles, following Dickson et al. (2007). After a 1% by-volume headspace was created, the sample was poisoned by the addition of 50 microlitres of saturated mercuric chloride solution (H_gC_l2) and made air-tight by sealing with greased (Apiezon L) ground-glass stoppers. The samples were stored in the dark at room temperature for analysis ashore.

Analytical methodology

Dissolved inorganic carbon (DIC) was measured by coulometry using a MARIANDA VINDTA 3C system (Mintrop, 2004), with carbon dioxide extracted from a calibrated volume of sample by addition of 8% phosphoric acid in excess. Two VINDTAs (serial numbers 11 and 24) were run simultaneously for DIC analyses.

Total alkalinity (TA) was measured using a two-stage potentiometric open-cell titration using a Scripps Total Alkalinity Titration System (Dickson et al., 2003). Weighed volumes were first acidified to pH 3.5-4 using 0.1 Molar hydrochloric acid while stirred and bubbled with air to remove evolved carbon dioxide, before the titration was continued to pH 3.0. TA was determined using a non-linear least-squares fit of the equivalence point of the titration curve.

Both analyses were calibrated using certified reference materials provided by Dickson Laboratory, Scripps Institution of Oceanography, U.S. (Batches 180 and 204; Dickson, 2010).

References Cited

Dickson, A., Afghan, J., & Anderson, G. 2003. Reference materials for oceanic CO2 analysis: a method for the certification of total alkalinity. Marine Chemistry, 80(2-3), 185-197. https://doi.org/10.1016/S0304-4203(02)00133-0

Dickson, A. G. 2010. Standards for ocean measurements, Oceanography, 23, 34-47, https://doi.org/10.5670/oceanog.2010.22

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.

Mintrop, L. 2004. Versatile instruments for the determination of titration alkalinity. Manual for versions 3S and 3C, Rep

JC278 Cruise report

Further information can be found in the JC278 Cruise report.

BODC Data Processing Procedures

Data received were loaded into the BODC database using established BODC data banking procedures. A parameter mapping table is provided below:

Data Quality Report

Accuracy based on analyses of reference material ranged from -0.96 to 1.80 micromoles per litre (n=31) for DIC and from -1.75 to 2.20 micromoles per litre (n=25) for TA. Precision for TA based on repeated measurements of bulk seawater was <1.08 micromoles per litre (n=5). Precision for DIC based on repeated measurements of bulk seawater was <1.5 micromoles per litre.

Flags from the originator marking suspect data were retained. The BODC flag 'L' was applied to these data. For CTD cast number 17, two high values of ALKYPOTK and TCO2KG01 (2359.51 micromoles per kilogram and 2283.12 micromoles per kilogram respectively) were flagged by the originator. In this same cast, TCO2CBTX had a value of 2159.2 micromoles per litre. This value had the BODC flag 'M' applied to indicate there may be a problem with the data point.

Project Information

Marine LTSS: AtlantiS (Atlantic Climate and Environment Strategic Science)

Introduction

AtlantiS is a five year (2024 to 2029) programme, funded by the Natural Environment Research Council (NERC).

Scientific Rationale

The global ocean is the largest part of the Earth's climate system and acts as a major buffer to climate changes resulting from human activities. By absorbing 90% of excess heat and nearly a quarter of carbon resulting from anthropogenic greenhouse gas emissions, the ocean has already substantially mitigated climate change in the atmosphere and on land. However, this service has come at a cost to the health and resilience of the ocean and by extension the people who depend on it. Significant damage has been caused to biodiversity and productivity of marine ecosystems, to shelf seas and coastal environments, and to inland areas through extremes of weather. The futures of regional climate and ecological systems depend on the response of the ocean to multiple anthropogenic stressors. Understanding and predicting the response is fundamental for sustainable development and to guide adaptation and mitigation.

The challenge is that the ocean is so large and variable that it cannot be completely and fully observed. Achieving adequate knowledge on all scales requires international coordination of observing and modelling over decades. It requires advancement in technology to expand our ability to observe beyond individual ships. It requires expanding the range of variables measured to include biogeochemistry and ecology. The opportunity now is to lead new capability to combine observations from a widening range of platforms and sensors, next-generation ocean and coupled models, and innovation in digital tools to meet the goal above. A range of national and international reviews have identified priority knowledge gaps related to natural and anthropogenically driven changes in the global ocean and the Atlantic and its shelf seas, and their impacts on marine ecosystems and human society:

• how natural and anthropogenic drivers of basin and decadal changes alter the Atlantic ecosystem, and the consequences for ecosystem functioning and services;
• the importance of ocean-shelf-coast connectivity in shaping ecosystems, biodiversity, natural hazards and impacts on society;
• the implications and feedbacks associated with climate mitigation strategies, and the need for improved assessments and advice to policy makers;
• the sensitivity and timescales of feedbacks that determine the ability of the ocean to continue to mitigate climate change by absorbing excess heat and carbon.

The aim of the AtlantiS programme is to provide evidence, tools and knowledge to support the ambition for healthy, biologically diverse and resilient marine environments, a sustainable blue economy and communities safe from natural hazards. The objectives are to strengthen the capacity of UK marine science to observe, model and predict the ocean through a step change in capability to maximise the value inherent in marine data; to transform the ocean from being data poor to data rich; to provide global syntheses of iconic climate change indicators; to lead an increase in public and government understanding of the role of the ocean in climate; and to communicate actionable knowledge effectively. AtlantiS is the continuation and development of the CLASS programme, enhancing the long-term, large-scale ocean observation systems and the ocean value-chain that contributes to key national and international programmes and priorities.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for JC278_CTD_JC278_CTD001

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.

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: