Metadata Report for BODC Series Reference Number 2053099

• 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

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.

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.

Surface Underway Macronutrients (SiO₂, NO₃+NO₂, NO₂, PO₄) for Cruise DY096

Originator's Protocol for Data Acquisition and Analysis

To provide detailed biogeochemical information of the Southern Ocean surface waters, the underway system of RRS Discovery was sampled every 6 hours during cruise DY096. Samples were collected unfiltered and directly frozen (-20 °C) for the determination of macronutrients. A total of 38 samples were collected and stored onboard the RRS Discovery for future analysis at the National Oceanography Centre.

A 4-channel Seal Analytical (QuAAtro 39) segmented flow-analyser with XY autosampler was used for the analysis of micro-molar concentrations of dissolved inorganic nutrients (silicate, phosphate, nitrate + nitrite, and nitrite). The samples were analysed using standard gas-segmented flow spectrophotometric techniques (Hydes et al., 2010). The Seal Analytical chemistry and cleaning procedure protocols used for the analyses of DY096 samples were:

1. Silicate in seawater method No. Q-066-05 Rev. 5

2. Phosphate in water method No. Q-064-05 Rev. 8

3. Nitrate and nitrite in seawater method No. Q-068-05 Rev.11

4. Nitrite in seawater method No. Q-070-05 Rev. 6

Back at NOC samples were defrosted overnight in the fridge and shaken to ensure a homogenous sample. Samples were measured in order of collection. Milli-Q water was used for the baseline and wash solution.

Standards
Standards were prepared by diluting the stock solutions of the different nutrients in artificial seawater (ASW) (35 g/L sodium chloride plus 0.2 g/L sodium hydrogen carbonate). Each run of the system had a 7-point calibration series. Prior to analysis all samples and standards were brought to room temperature of ~20 °C. Concentrations of the working standards were based upon the concentrations range of the nutrients expected.

Instrument Description

SEAL Analytical QuAAtro Autoanalyser

References Cited

Hydes D. J., Aoyama M., Aminot A., Bakker K., Becker S., Coverly S., Daniel A., Dickson A. G., Grosso O., Keroue R., van Ooijen J., Sato K., Tanhua T., Woodward E. M. S., Zhang J. Z. (2010). Determination of dissolved nutrients (N, P, Si) in seawater with high precision and inter-comparability using gas-segmented continuous flow analysers. The GO-SHIP Repeat Hydrography Manual : A Collection of Expert Reports and guidelines. IOCCP Report No 14, ICPO Publication Series No. 134, version 1, 2010.

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

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

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

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

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

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

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

DY096 Cruise report

Further information can be found in the DY096 Cruise report.

BODC Data Processing Procedures

Data were submitted in an .xlsx spreadsheet containing dissolved nutrient sample measurements of silicate, nitrate + nitrite, phosphate, and nitrite. Additional metadata such as position, date, and time were also included in the file. The data were reformatted and assigned BODC parameter codes. Quality control checks were made and BODC applied flags were applicable. The data were then loaded into the BODC database using established BODC data banking procedures.

A parameter mapping table is provided below:

Data Quality Report

The originator carried out the following data quality performance checks:
In order to test the accuracy and precision of the analyses, CRMs from The General Environmental Technos Co., Ltd., (KANSO) were measured in triplicates at the start and end of every run. For the analyses of DY096 samples KANSO CRMs lot CD, CJ and CB were used.
Various points are flagged as questionable in the underway data.

BODC performed quality control checks on the data. Any originator flags were mapped to standard BODC flags. Any data values which were below the detection limit of the instrument were applied a '<' flag.

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

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: