Metadata Report for BODC Series Reference Number 2022899

• 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

Digitron TM-22 Digital Thermometer

The Digitron TM-22 is a water-resistant, hand-held digital thermometer. It complements Digitron's PM series of pressure instruments. Its typical battery life is 500 hours from two AA or equivalent cells. Temperature measurements are available in Celsius or Fahrenheit with a temperature range of -200 degC to +1350 degC/ -328 degF to +2462 degF.

For more information please see the document https://www.bodc.ac.uk/data/documents/nodb/pdf/digitron_tm22_datasheet.pdf.

Metrohm 794 Basic Titrino Titrator

The Metrohm 794 Basic Titrino is an all-purpose titrator used for dynamic and monotonic determination of solution concentrations. Titration modes of the instrument are constant or depending on the titration curve variable dosing of the titration reagent and Endpoint-Titration. The operation modes include; Dynamic Equivalence-point Titration (DET), Monotonic Equivalence-point Titration (MET), Set Endpoint Titration (SET), pH Calibration (CAL), Measuring (MEAS) and Titration Procedure (TIP) which links various commands and methods to a titration procedure. All operating modes of the Titrino can be combined to perform extensive analytical sequences.

Ready-to-start methods for the most common applications are stored in the internal method memory for example; the determination of the hardness of drinking water, diazotation of sulfonamides and primary amines, and determination of the peroxid number of edible oil sand fats. The operator is free to modify and overwrite the methods or to create and store new titration sequences.

The instrument consists of an exchange unit with a small display, which can be connected to either a magnetic stirrer (728), propeller rod stirrer (802) or Ti stand (703 or 727). Data exchange with a PC is possible with the Metrodata VESUV Software and with Metrodata TiNet Software complete keypad remote control, data acquisition and evaluation via PC is enabled.

Further details can be found in the manufacturer's user manual.

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.

DY039 Discrete Oxygen Samples Processing Document

Originator's Protocol for Data Acquisition and Analysis

Water samples were collected from 18 CTD casts during cruise DY039. The samples were obtained using an SBE 911plus CTD unit with 24 Niskin bottles (10 litre) fitted to the rosette. For the majority of casts, samples were collected from 12 Niskin bottles, plus an additional 4 samples which served as replicates.

Oxygen concentrations were measured using Winkler titration. A Metrohm 794 Titrino system was used with an amperometric electrode and a 776 Dosimat unit to deliver the thiosulphate titrant.

More information can be found in Rayner (2016).

References

Rayner, D. (2016) RRS Discovery Cruise DY039, 17 Oct - 01 Dec 2015, Southampton, UK to Nassau, Bahamas. RAPID Moorings cruise report. Southampton, UK: National Oceanography Centre, Southampton, 183pp. (National Oceanography Centre Southampton Cruise Report, No. 37)

BODC Discrete Data Processing Procedures

The originators CSV format was converted to ASCII. The data were then loaded into the project database under the ORACLE Relational Database Management System without modification. Data that lay outside the permitted range for the parameter code were flagged suspect. No replicates were supplied to BODC.

A mapping of the variables supplied by the originator to BODC parameter codes is given below.

Below is a mapping of the data flags used by the originator to the equivalent BODC flag. The data flags used by the originator were according to WOCE table 4.9.

Project Information

Atlantic BiogeoChemical Fluxes (ABC Fluxes)

Introduction

Users of these data are referred to the Atlantic BiogeoChemical Fluxes website for more information. The following text has been taken from the website.

Scientific Rationale

The North Atlantic Ocean plays a pivotal role in the global carbon cycle, by storing carbon released into the atmosphere when fossil fuels are burned, and by supporting the sinking flux of organic matter.

Our understanding of how horizontal oceanic fluxes in the subtropics contribute to these processes is largely based on shipboard expeditions which occur every 5 years at 24°N. Sampling at that interval is insufficient to resolve and understand the role that horizontal transfers play in regulating these processes.

Time-series of temperature, salinity and current speeds from the RAPID array at 26°N indicate that the fluxes vary on a range of timescales. Measuring this variability will almost inevitably modify our understanding of the role played by the subtropical North Atlantic in the global carbon cycle.

ABC Fluxes addresses these issues by deploying new chemical sensors and samplers on the RAPID mooring array, by using the new observations to calculate time-series of nutrient and inorganic carbon fluxes across 26°N, and by interpreting this data in the light of other observations and the output of biogeochemical models.

Research objectives

• To calculate time series (including uncertainty estimates) of inorganic carbon and nutrient fluxes in the Atlantic at 26.5°N using a hierarchy of approaches including new observations.
• To determine how nutrient fluxes control the strength and variability of nutrient inventories and export production in the subtropical gyre.
• To determine how inorganic carbon fluxes drive the size and variability of the anthropogenic carbon inventory and air-sea carbon fluxes in the North Atlantic.

Assessing the North Atlantic's role in the global carbon cycle

Starting with existing observations, followed by new oxygen observations and finally direct observations of the carbon and nutrients, ABC Fluxes will identify the added value of each successive set of observations.

Direct flux calculations will be interpreted as contributions to the North Atlantic budget in conjunction with other observations and models, to assess how oceanic fluxes control the strength and variability of the role the North Atlantic plays in the global carbon cycle.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for DY039_CTD_CTD014

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: