Metadata Report for BODC Series Reference Number 1879464

• 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

SIS Instruments Dissolved Oxygen Analyser

The SIS Instruments Dissolved Oxygen Analyser (DOA) is a PC controlled instrument which is used for the determination of dissolved oxygen in aqueous solutions by the Winkler (1888) titration method. The system consists of a transportable box containing a Metrohm 765 Dosimat motor burette, alternating light photometer and an interface box which provides, via an RS 232 serial link, communication between computer and the instruments. The box also contains a stand with a stirrer used to hold the sample flask. The titration endpoint is determined by eye. Alongside the DOA, SIS instruments provide Windows database and processing software, which is required for data storage and post-processing of the acquired data.

Specifications

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.

Discrete Oxygen Samples from CTD bottles for RRS Discovery Cruise DY031

Originator's Protocol for Data Acquisition and Analysis

Water samples were drawn from the CTD rosette bottles deployed during the cruise with samples taken from 80 of the total of 85 CTD casts undertaken.

Dissolved oxygen (DO) concentrations were measured in discrete seawater samples collected during DY031. Sampling and analysis were performed 24 hours a day using Winkler photometric auto-titration following 'Go-Ships' protocols (Langdon, 2010) based on the standard methodologies of Carpenter,1965 adapted for large scale hydrographic studies (e.g. Culberson, 1991 and Dickson, 1995). For more information see the cruise report.

References

Carpenter, J.H. 1965. The Chesapeake Bay Institute technique for the Winkler dissolved oxygen method. Limnol.and Oceanogr. 10:141-143.

Culberson, C.H. 1991. Dissolved Oxgyen. WHPO Publication 91-1.

Dickson, A.D. 1995. Determination of dissolved oxygen in sea water by Winkler titration. WOCE Operations Manual, Part 3.1.3 Operations and Methods, WHP Office Report WHPO 91-1.

Langdon. C. 2010. Determination of dissolved oxygen in seawater by Winkler titration using the amperometric technique. The GO-SHIP Repeat hydrography manual: A collection of expert reports and guidelines. IOCCP report No.14.

BODC Data Processing Procedures

The sample data were supplied to BODC in MStar format. Data received were loaded into the BODC database using established BODC data banking procedure. Originator's parameters were mapped with BODC codes as follows;

Project Information

NOCS National Capability

The National Oceanography Centre Southampton National Capability focuses on long term science concerned with basin/decadal variability of the Ocean.

Data Activity or Cruise Information

Data Activity

No Document Information Held for the Series

Related Data Activity activities are detailed in Appendix 1

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Ellett Line/Extended Ellett Line: Station 7G

Station 7G is one of the fixed CTD stations, which together form The Extended Ellett Line. The line lies between Iceland and the Sound of Mull (Scotland) crossing the Iceland Basin and Rockall Trough via the outcrop of Rockall. As part of this initiative, CTD dips, together with associated discrete sampling of the water column, have typically been carried out annually at this station since September 1996.

Prior to September 1996, Station 7G was part of a shorter repeated survey section, consisting of 35 fixed stations, known as The Ellett Line (originally termed the Anton Dohrn Seamount Section). This line incorporated those stations across the Rockall Trough and Scottish shelf between Rockall and the Sound of Mull and was visited at regular intervals (usually at least once a year) between 1975 and January 1996. During this period Station 7G was also referred to as Station C5.

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: DY031_CTD_DY031_079

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: Ellett Line/Extended Ellett Line Station 7G

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.