Metadata Report for BODC Series Reference Number 2047499

• 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

Shimadzu TOC-L Total Organic Carbon Analyser series

A series of total organic carbon analysers designed to make sample measurements of total carbon (TC), inorganic carbon (IC) and non-purgeable organic carbon (NPOC); total organic carbon (TOC) can be calculated by subtracting IC from TC measurements. The instrument uses the 680 degrees Celsius combustion catalytic oxidation method to analyse aqueous samples, and optionally solid and gas samples. An optional accessory enables the measurement of particulate organic carbon (POC) and total nitrogen (TN). Each analyser is available as an LCD and keyboard-equipped standalone model, or as a PC-controlled model. The measurement range of Total Carbon is 4 µg/L to 30000 mg/L, with a detection limit of 4 µg/L and an accuracy of 1.5%.

For more information, please see this document: https://www.bodc.ac.uk/data/documents/nodb/pdf/415_c391e079g.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.

Dissolved Organic Carbon for Cruise JR15007

Originator's Protocol for Data Acquisition and Analysis

Sampling Collection

DOC samples were taken from each deep CTD cast and were collected after oxygen (either first, or second in order). They were collected straight from the valve, after triple rinsing with sea water, into triple MilliQ rinsed 1 L HDPE bottles. In the main laboratory, for each water sample, a glass filtration rig made up of a 45 mm deep and 0.7 µm pore sized glass fibre filter (GFF) was flushed through with sample water four times before 20 ml of water was collected into a pre-acidified (20 µl hydrochloric acid, 50 % v/v HCl) 20 ml glass vial with a screw cap and septum. GFFs were changed every four to five samples. Following each CTD cast, the rig was dismantled and placed in a 10 % acid bath overnight. Prior to sampling, the rig was rinsed, reassembled and covered in muffled foil (350 °C for 24 hours). Samples were stored upright in the 4 °C fridge prior to analysis at the University of Liverpool.

Sample analysis

Concentrations of dissolved organic carbon were determined on Shimadzu TOC-V and TOC-L analysers. Internal calibration standards of KHP, glycine and leucine were used and reference materials from the University of Miami (Hansell lab) were run every 4-6 samples. Results were used if an average concentration was within the accepted range of the certified value.

References Cited

Pan, X., Achterberg, E. P., Sanders, R., Poulton, A. J., Oliver, K. I. C., & Robinson, C. 2014. Dissolved organic carbon and apparent oxygen utilization in the Atlantic Ocean. Deep Sea Research Part I: Oceanographic Research Papers, 85, 80?87. doi:10.1016/j.dsr.2013.12.003

JR15007 Cruise report

Further information can be found in the JR15007 Cruise report.

BODC Data Processing Procedures

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

Data Quality Report

On the 13^th of June 2016 samples were collected in the water column above a hydrothermal vent. This can be seen reflected in the dissolved organic carbon values.

Project Information

A nutrient and carbon pump over mid-ocean ridges (RidgeMix)

RidgeMix is a five year (August 2014 to February 2019) research programme which received funding from the Natural Environment Research Council (NERC). The aim of the programme was to address the problem of how deep nutrients are transported into the surface waters in mid-latitudes, by testing a new view: tides passing over the mid-Atlantic ridge generate enhanced turbulence and mixing, which in turn provides a nutrient supply to the upper thermocline waters. These nutrients are then transported horizontally along density surfaces over the western side of the basin, probably being swept along the Gulf Stream and eventually passing into the winter mixed surface layer. When this surface layer shallows and warms in spring, the nutrients are then available to the phytoplankton.

Fieldwork involved collecting measurements of the turbulence and nutrient concentrations over and adjacent to the Mid-Atlantic Ridge, using a novel long-term moored array of instruments along the ridge, deployed over a five-week research cruise. Sampling was done sufficiently quickly to resolve tidal changes in currents and mixing over the ridge. A second component of the fieldwork will use computer models of circulation in the Atlantic to explore the wider implications of the fieldwork observations, to determine whether or not mixing over the mid-Atlantic ridge really does provide enough nutrients to explain the phytoplankton production in the mid-latitude North Atlantic.

RidgeMix was a collaborative project involving five organisations, of which three were UK based and two were US based. The project was led by the Professor Jonathan Sharples, University of Liverpool, Earth, Ocean and Ecological Sciences. Collaborators were:

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for JR15007_CTD_CTD_043

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

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:

Appendix 1: JR15007_CTD_CTD_043

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.