Metadata Report for BODC Series Reference Number 2053247

• Metadata Summary

• Problem Reports

• Data Access Policy

• Data 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

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

Access to these data is currently restricted to the consortium Principal Investigators and consortium co-workers. Anyone granted permission to use the data during this period of restriction must acknowledge the data originator on any resulting papers.

Data Policy

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

The following data policy has been approved by the Principal Investigator and applies to all datasets received under the CUSTARD project.

Designated Data Centres

Data arising from the project are lodged with the British Oceanographic Data Centre (BODC) or the UK Polar Data Centre (UK PDC) on acquisition, together with such metadata as are defined under the NERC data policy.

BODC - Physical and chemical oceanography data are held at BODC. This includes data from CTD, data from the ship's fixed sensors, gliders, mooring, Red Camera Frame, Marine Snow Catcher (MSC), Underwater Vision Profile (UVP), incubation experiments, etc.

PDC - Biological oceanography data are submitted to BODC, but held at and disseminated by PDC. This includes plankton biomass and microscopy data.

Embargo & Open Access

Two dataset types are each subject to one-year embargo, and are thus made public no earlier than January 2021:

• Nitrate and silicate data measured from the NOC lab-on-chip sensors mounted on the Ocean Observatories Initiative (OOI) mooring. The embargo will start from the time of processed data submission to BODC, and end 12 months later.
• All data collected by the Slocum gliders (MARS and Rutgers). The embargo will start from the date of the latest glider recovery, and end 12 months later.

Beyond the embargo expiry date, the data are openly provided by the data centres under the Natural Environment Research Council (NERC) Open Data policy.

All other datasets are freely accessible as soon as they are available under the same NERC policy.

The following attribution statement must always be used to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council".

Narrative Documents

SEAL Analytical QuAAtro colorimetric autoanalyser

The SEAL QuAAtro high Performance Microflow Analyzer is the latest generation of the original world-class Technicon^TM Segmented Flow Analysis (SFA) systems.

A basic SFA system consists of an autosampler, a peristaltic pump, a chemistry manifold, a detector and data acquisition software. Sample and reagents are pumped continuously through the chemistry manifold. Air bubbles are introduced at regular intervals forming unique reaction segments which are mixed using glass coils. Glass is ideal, as it is inert, stays clean and enables easy visual checks.

In SFA, reactions run to completion and the ratio of sample to reagents in the detector reaches a constant maximum value. This results in ultra-low detection limits and exceptional reproducibility. Variations in reaction time, temperature and sample matrix do not affect the results as they do in other colorimetric techniques, such as flow injection analysis, where the reaction is not brought to completion.

QuAAtro is a microflow SFA system, the internal diameter of all glassware being 1 mm. This reduces reagent consumption and increases throughput, with most methods running at 100 - 120 samples hour. The integrated enclosed manifold and detector are heated to 37 °C. Flow stability is ensured as the optimal bubble frequency for each method is programmed by silent air valves. Automatic start-up, method changeover and shutdown allows true unattended operation and overnight running. QuAAtro checks its own performance, with automatic monitoring of noise, drift, bubble pattern and light energy, before and during a run.

Up to four methods can run at the same time on one console, and there is a special 5-channel version for nutrients in seawater. Two consoles can be combined to give an 8-channel system.

Further details can be found in the manufacturer's specification sheet.

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.

Bottle Macronutrients (SiO₂, NO₃+NO₂, NO₂, PO₄) for Cruise DY111

Originator's Protocol for Data Acquisition and Analysis

A total of 46 CTD casts were made in the South East Pacific Ocean on cruise DY111, 26 casts with 20 L niskin bottles on a steel frame and 20 casts with 10 L OTE-bottles on a titanium frame. The casts were made at 3 fixed sites (TN, TS, and OOI), at two points (shakedown, Argos), and at four points along a transect between the three fixed sites.

The bottles were analysed for nitrate and nitrite (NO₃+NO₂), silicate (SiO₂), nitrite (NO₂), and phosphate (PO₄). The water samples were drawn from the bottles into pre-labelled 15 ml centrifuge tubes. Each tube was rinsed three times with the same water as the sample was taken from and then filled to 10-15 ml marks.

Analysis was within 24 hours of the samples being taken and on a QuAAtro 39 segmented flow autoanalyser linked to a XY-2 Sampler, both by SEAL Analytical UK Ltd, and controlled via a DELL Latitude laptop using the appropriate software package supplied by SEAL, called AACE 7.09. The chemistry methods used were also supplied by SEAL (Q-068-05, Q-066-05, Q-070-05, Q-064-05).

During runs ultra-pure water (MilliQ) was used as a wash to provide the baseline, and was also the matrix that the stock calibrant solutions were made up in. An artificial seawater solution was used to prepare a range of calibration standard solutions (see DY111 Cruise report for more details). The correlation coefficient for all chemistries during all runs was higher than 0.9990. In fact, the lowest value seen throughout DY111 was 0.9993 and this low value only occurred once. All other values were 0.9999 or higher.

The efficiency of the reduction from NO₃ to NO₂ by the cadmium (Cd) coil was calculated by comparing a single NO₂ standard against a single NO₃ standard (10 µmol/l each). The efficiency of the Cd column never dropped below 100 %.

Two sets of certified reference materials (CRM Lots CJ and CB, KANSO, Japan) were measured at the start and the end of each sample run. These values were then used to calculate random and systematic uncertainties of each measurement, following Birchill et al. (2019). The detection limit was calculated from 10 replicates of the lowest concentration standard for each run.

The baseline (or offset) of the wash solution was always set at 5 % of the chart window. The actual absorbance values for the baseline were recorded before starting each run to give an indication of stability of the wash solution and/or cleanliness of the system. The gain was set by running the highest sample through the system and selecting 'set gain' in the software. The chart window was then automatically adjusted so that the top standard peak sits at the 90 % point. The sampling time was 80 seconds per sample and 20 per wash. This ensured a nice stable section reading with no interference from density gradients.

Instrument Description

SEAL Analytical QuAAtro 39 segmented flow autoanalyser linked to a XY-2 Sampler

References Cited

Birchill, A.J.; Clinton-Bailey, G.; Hanz, R. ; Mawji, E.; Cariou, T.; White, C.; Ussher, S.J.; Worsfold, P.J.; Achterberg, E.P.; Mowlem, M.. 2019 Realistic measurement uncertainties for marine macronutrient measurements conducted using gas segmented flow and Lab-on-Chip techniques. Talanta, 200. 228-235. https://doi.org/10.1016/j.talanta.2019.03.032

Certified Reference Material KANSO CRM Lot.CB http://www.kanso.co.jp/eng/pdf/certificate_cb.pdf

Certified Reference Material KANSO CRM Lot.CJ http://www.kanso.co.jp/eng/pdf/certificate_cj.pdf

SEAL Analytical Q-068-05 Rev. 12 QuAAtro Application Nitrate and Nitrite in Water and Seawater Q-068-05 Rev. 12

SEAL Analytical Q-066-05 Rev. 5 QuAAtro Application Silicate in Water and Seawater Q-066-05 Rev. 5

SEAL Analytical Q-070-05 Rev. 7 QuAAtro Application Nitrite in Water and Seawater Q-070-05 Rev. 7

SEAL Analytical Q-064-05 Rev. 8 QuAAtro Application Phosphate in Water and Seawater Q-064-05 Rev. 8

US EPA 40 CFR part 136, appendix B. 'Definition and Procedure for the Determination of the Method Detection Limit'.

DY111 Cruise report

Further information can be found in the DY111 Cruise report.

BODC Data Processing Procedures

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

Data Quality Report

Data were flagged by the originator based on whether the values were considered probably bad/bad (converted to BODC flag L) and when the values were below the detection limit (converted to BODC flag <). In this case, the limit of detection (LoD) is defined as the standard deviation of multiple measurements of a near-zero sample (lowest calibration standard) multiplied by a factor between 2.3 and 3.1 depending on the number of measurements (see USA EPA). The detection limits for each parameter, which depend on the run, ranged as follows:

Values below this limit are represented by the LoD of that run and associated with the appropriate BODC flag, <, unless the value was also considered bad, in which case the value given is the LoD but it is flagged L (as per agreement with the originator).

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_UCCTD_CTD014T

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: