Metadata Report for BODC Series Reference Number 1289231

• 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

These data have no specific confidentiality restrictions for users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.

If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:

"Contains public sector information licensed under the Open Government Licence v1.0."

Narrative Documents

Technicap NOEX bottle

The Technicap NOEX water bottle was designed for oceanographic sampling. The bottle comprises a plastic tube with caps at each end and is deployed with the caps held open, then closed at the target depth. Multiple bottles can be deployed on a CTD frame rosette. Bottle capacity is variable, but normally several litres. The bottle was developed by Technicap in the 1990s but has been superseded by more recent models. There is no known source of support available for this sampler.

Nutrients for Charles Darwin and RRS Challenger cruises

Document History

Converted from CDROM documentation.

Content of data series

Data Originator

Dr Ken Jones, CCMS Dunstaffnage Marine Laboratory, UK.

Sampling strategy and methodology

Charles Darwin cruises CD92B, CD93A and CD93B and RRS Challenger cruises CH120, CH121B, CH123B, CH124, CH125B, CH126B and CH128A.

Samples were collected using either Niskin bottles deployed on a CTD rosette (CD93A, CD93B, CH121B, CH123B, CH125B, CH126B and CH128A) or NIO bottles deployed on a hydrographic wire in conjunction with a CTD cast (CD92B, CH120 and CH124).

The samples were transferred to a refrigerator at 4°C immediately after collection and were analysed within a few hours on a Lachat autoanalyser using standard colorometric chemistry.

Comments on data quality

An intercalibration of the two nutrient data sets was carried out. Simple regression, excluding data values deemed suspect, yielded the following equations:

POL NO₃+NO₂ = 0.93 DML NO₃+NO₂ - 0.14 (R² = 0.80)
POL PO₄ = 0.84 DML PO₄ + 0.07 (R² = 0.78)

The POL nutrient values are systematically significantly lower than the DML data. When individual data values are inspected it can be seen that in some samples the POL values are down to a half of the DML values. This nutrient loss may be attributed to biological activity during sample storage.

The POL data were primarily collected to allow estimation of dissolved organic nitrogen and phosphorus from contemporary total nitrogen and phosphorus determinations. It is therefore recommended that the DML data be used for all considerations of ambient nutrient concentrations and that the POL data be considered as metadata for the TDN and TDP data.

Project Information

LOIS Shelf Edge Study (LOIS - SES)

Introduction

SES was a component of the NERC Land Ocean Interaction Study (LOIS) Community Research Programme that made intensive measurements from the shelf break in the region known as the Hebridean Slope from March 1995 to September 1996.

Scientific Rationale

SES was devoted to the study of interactions between the shelf seas and the open ocean. The specific objectives of the project were:

• To identify the time and space scales of ocean-shelf momentum transmission and to quantify the contributions to ocean-shelf water exchange by physical processes.

• To estimate fluxes of water, heat and certain dissolved and suspended constituents across a section of the shelf edge with special emphasis on net carbon export from, and nutrient import to, the shelf.

• To incorporate process understanding into models and test these models by comparison with observations and provide a basis for estimation of fluxes integrated over time and the length of the shelf.

Fieldwork

The SES fieldwork was focussed on a box enclosing two sections across the shelf break at 56.4-56.5 °N and 56.6-56.7 °N. Moored instrument arrays were maintained throughout the experiment at stations with water depths ranging from 140 m to 1500 m, although there were heavy losses due to the intensive fishing activity in the area. The moorings included meteorological buoys, current meters, transmissometers, fluorometers, nutrient analysers (but these never returned any usable data), thermistor chains, colour sensors and sediment traps.

The moorings were serviced by research cruises at approximately three-monthly intervals. In addition to the mooring work this cruises undertook intensive CTD, water bottle and benthic surveys with cruise durations of up to 6 weeks (3 legs of approximately 2 weeks each).

Moored instrument activities associated with SES comprised current measurements in the North Channel in 1993 and the Tiree Passage from 1995-1996. These provided boundary conditions for SES modelling activities.

Additional data were provided through cruises undertaken by the Defence Evaluation and Research Agency (DERA) in a co-operative programme known as SESAME.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for CH124_CTD_CTD19

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

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 1

Fixed Station Information

Ellett Line

The Ellett Line is a hydrographic transect consisting of 35 individual fixed stations which were occupied, usually at least once a year, between 1975 and 1996. The time series is named after the scientist David Ellett, who coordinated the survey work at Dunstaffnage Marine Laboratory (DML), near Oban. The transect ran between the north west coast of Scotland to the small outcrop of Rockall, via the Anton Dohrn Seamount - a prominent bathymetric feature in the Rockall Trough (see map). STD/CTD dips and associated water sampling for the analysis of nutrients were routinely performed during each station occupation.

In 1996 the transect was lengthened to incorporate new additional fixed stations crossing the Iceland Basin from Rockall to Iceland. This transect, which is still routinely occupied annually, is now known as the Extended Ellett Line and is a collaborative effort between scientists at Dunstaffnage Marine Laboratory and the Southampton site of the National Oceanography Centre (NOC).

Map of standard stations (1975-1996)

Map produced using the GEBCO Digital Atlas

The white triangles indicate the nominal positions of the Ellett Line stations (1975- 1996). Measurements made along the Ellett Line lie within a box bounded by co-ordinates 56° 40.02' N, 13° 42.0' W at the south west corner and 57° 37.2' N, 6° 7.98' W at the north east corner.

Nominal Ellett Line stations (1975-1996)

Listed below are nominal details of the standard hydrographic stations that formed the Ellett Line between 1975 and January 1996.

History of Ellett Line occupations (1975-January 1996)

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: 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.

Appendix 2: Ellett Line

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.