Metadata Report for BODC Series Reference Number 2243870

• 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.

CTD Bottle Dissolved Inorganic Carbon (DIC) and Total Alkalinity (TA) for CUSTARD Cruise DY111

Originator's Protocol for Data Acquisition and Analysis

Sampling methodology

Water sampling for the determination of total dissolved inorganic carbon (DIC) and total alkalinity (TA) occured between 04 December 2019 to 06 January 2020 inclusive from a total of 24 CTD casts. The Niskin bottles from 23 of the CTD casts were made of stainless steel, and the remaining one cast used titanium Niskin bottles. Water was drawn directly from Niskin bottles on the CTD rosette using Tygon tubing and collected in 250 mL borosilicate bottles. The bottles were stored until analysis, usually no later than two days. Bottles were rinsed and filled smoothly from the bottom, avoiding the formation of air bubbles, overflowing the water by at least a half bottle volume. A stopper was put on immediately. Samples were prepared for their storage leaving a headspace of 1% of the bottle volume and adding 200 µL of saturated mercuric chloride (HgCl₂) solution to prevent biological alteration of the sample. Each bottle was sealed with a glass stopper covered with grease and sealed with a rubber band, then stored in the dark at room temperature until analysis.

Analytical methodology

Concentration of DIC per unit of mass of the seawater was measured by coulometry (Johnson et al., 1993; DOE, 1994). TA per unit mass of the seawater was measured by titration, using curve fits along modified Gran plots (Gran, 1952; Bradshaw, 1981; Dickson, 1981; DOE, 1994). The systems use a Metrohm Titrino 719S for adding acid, an ORION-Ross pH electrode and a Metrohm reference electrode. The burette, the pipette (volume approximately 100 mL), and the analysis cell have a water jacket around them at 25°C. The titrant (0.1 M hydrochloric acid) was made at the University of East Anglia.

Analysis for TA and DIC was performed on two integrated VINDTA systems (Versatile Instrument for Determination of Titration Alkalinity, MARIANDA, Kiel, Germany, instruments V4 and V7 version 3C). Samples were at 25°C immediately before and during the analysis. The accuracy of the analyses was assured using certified reference material (CRM, batch 182, supplied by Dr. A. Dickson, Scripps Institute of Oceanography).

References Cited

Bradshaw, A.L., Brewer, P.G., Shafer, D.K., Williams, R.T., 1981. Measurements of total carbon dioxide and alkalinity by potentiometric titration in the GEOSECS programme. Earth and Planetary Science Letters, 55, 99-115.

Dickson, A.G., 1981. An exact definition of total alkalinity and a procedure for the estimation of alkalinity and total inorganic carbon from titration data. Deep-Sea Research, 28A, 609-623.

DOE, 1994. Handbook of methods for the analysis of the various parameters of the carbon dioxide system in sea water. Version 2, A. G. Dickson and C. Goyet, eds. ORNL/CDIAC-74.

Gran, G., 1952. Determination of the equivalence point in potentiometric titrations. Analyst, 77, 661-671.

Johnson, K.M., Wills, K.D., Butler, D.B., Johnson, W.K., Wong, C.S., 1993. Coulometric total carbon dioxide analysis for marine studies: maximizing the performance of an automated gas extraction system and coulometric detector. Marine Chemistry, 44, 167-187.

DY111 Cruise report

Further information can be found in the DY111 Cruise report.

BODC Data Processing Procedures

Data received were loaded into the BODC database using established BODC data banking procedures. No unit conversion was necessary as the data were provided in equivalent units to the assigned BODC parameter code. A parameter mapping table is provided below:

Data Quality Report

Where originators have applied quality control flags, these have been converted to the BODC quality flag system. Data originators were contacted to confirm the quality flags used. Data originators have stated that the internal consistency between measured DIC, TA, and underway pCO₂ (pCO₂ from PML) is not adequate.

Project Information

Carbon Uptake and Seasonal Traits of Antarctic Remineralisation Depth (CUSTARD)

Carbon Uptake and Seasonal Traits of Antarctic Remineralisation Depth (CUSTARD) is a £1.8 million, four-year (2018-2022) research project funded by the Natural Environment Research Council (NERC).

The main aim of the CUSTARD project is to quantify the seasonal drivers of carbon fluxes in a region of the Southern Ocean upper limb, and estimate how long different quantities of carbon are kept out of the atmosphere based on the water flow routes at the observed remineralisation depths. Please visit the CUSTARD web page for more information

CUSTARD is one of three projects funded as part of the Role of the Southern Ocean in the Earth System (RoSES) programme, also known as the Southern Ocean programme. Please see the RoSES project document for more information on the wider programme and the research projects associated with it.

Background

The upper limb of the Antarctic Circumpolar Current (ACC) represents an important junction in the marine carbon cycle, as the fate of carbon fixed by surface phytoplankton will differ according to how deep it penetrates before being remineralised. If shallow remineralisation occurs, carbon will follow the upper limb circulation and upwell further north, escaping into the atmosphere within decades. On the other hand, deep remineralisation will result in carbon entering the lower limb circulation, with the potential of being retained in the ocean for hundreds of years. Seasonality in plankton dynamics play an important role in remineralisation depth, and CUSTARD aims to resolve all factors contributing to the carbon export out of the region.

Participants

Six different UK-based organisations are directly involved in research for CUSTARD:

• National Oceanography Centre (NOC)
• NERC British Antarctic Survey (BAS)
• University of Southampton
• University of Oxford
• Plymouth University
• University of East Anglia (UEA)

CUSTARD collaborates closely with the US Ocean Observatories Initiative (OOI) program through sharing of instruments and platforms at and around the Global Southern Ocean Array. OOI is funded by the National Science Foundation (NSF) and is managed by the Woods Hole Oceanographic Institution. Rutgers University maintains the cyberinfrastructure component, working alongside CUSTARD scientists in the handling and distribution of shared observational data.

Research details

Four Work Packages have been funded by the CUSTARD project, each addressing a separate project objective within the region of study in the south eastern Pacific ocean. These are described briefly below:

• Work Package 1: Obtain an accurate picture of the seasonal air-sea flux and macronutrient drawdown.
  This work package aims at determining the magnitude and variability of air-sea CO2 fluxes and their physical and biogeochemical drivers. High-resolution carbon measurements in the water column, CO2 flux estimates and daily resolved nitrate and silicate observations are combined to better understand the link between seasonal changes in CO2 fluxes and biological variability.

• Work Package 2: Quantify the link between iron and silicate availability and remineralisation depth.
  This work package investigates the annual cycle of phytoplankton dynamics, net production and export of organic material in conjunction with iron availability.

• Work Package 3: Observationally determine the seasonal cycle in remineralisation depth.
  This work package assesses remineralisation depth and its variability using marine snow catchers deployed during the process cruise, and backscatter measurements carried out year-round by gliders.

• Work Package 4: Examine the link between seasonality and remineralisation depth and the trajectory of carbon from the surface out of the upper limb.
  This work package aims to ingest all CUSTARD observational data into models to determine whether seasonal variability in phytoplankton composition is reflected in changes in remineralisation depth, which in turn leads to seasonal variability in the fate of organic carbon leaving the Southern Ocean via the upper limb.

Fieldwork and data collection

All the observational data from the project is collected at and south of the Ocean Observatories Initiative (OOI) Global Southern Ocean Array, located south-west of Chile. Data collection activities span from November 2018 to January 2020, and include three cruises, four glider missions, and one mooring.

Cruises

All cruises depart from and return to Punta Arenas (Chile). Cruise activities include deployments and recovery of gliders and a mooring, Conductivity, Temperature and Depth (CTD), trace metal clean GoFlo bottle sampling, Red Camera Frame, Marine Snow Catcher and Underwater Vision Profiler deployments, as well as laboratory incubations with sea water samples. See cruise details below:

Gliders

Two Slocum 1000 MARS gliders (Pancake and Churchill) are deployed from DY096, to collect data continuously for one year until recovery on DY111. The gliders are mounted with CTD sensors, an optode, a fluorometer, and twin backscatter sensors. Pancake failed and its mission ended early in February 2019.

One Rutgers University glider is deployed from DY111, to collect data until recovery at the end of the same cruise. The glider is owned by Rutgers University and the data is shared with CUSTARD. It carries CTD sensors, an optode, a fluorometer, a backscatter sensor and a particle size analyser.

Mooring

Deployment of Global Surface Mooring GS01SUMO-00004 (SUMO-4) during DY096, to take continuous measurements for approximately one year until recovery during DY112. Its location is roughly 54 28 S, 89 02 W. This is an OOI mooring provided and deployed by WHOI, and adapted to integrate NOC lab-on-chip nitrate and silicate sensors.

Contacts

Dr. Adrian Marin (National Oceanography Centre, UK) - Lead Principal Investigator and lead of Work Package 4
Dr. Dorothee Bakker (University of East Anglia, UK) - Lead of Work Package 1
Prof. Mark Moore (University of Southampton, UK) - Lead of Work Package 2
Dr. Stephanie Henson (National Oceanography Centre / University of Southampton, UK) - Lead of Work Package 3

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for DY111_CTD_CTD015S

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

Fixed Station Information

Fixed Station - Ocean Observatories Initiative (OOI) Global Southern Ocean Array

OOI Southern Ocean Array is an offshore site situated in the South Pacific to the south west of Chile, in an area of large scale thermohaline circulation, intermediate water formation, and CO₂ sequestration. The array originally comprised four moorings and a combination of Open Ocean and Profiling Gliders. All of the moorings were successfully recovered for the last time in January 2020.

The following is a list of the cruises involved in recovery and deployment of the moorings:

More information can be found at: https://oceanobservatories.org/array/global-southern-ocean-array/

Related Fixed Station activities are detailed in Appendix 2

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: DY111_CTD_CTD015S

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.

Appendix 2: OOI-Southern Ocean

Related series for this Fixed Station 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.