Metadata Report for BODC Series Reference Number 845027

Metadata Summary

Data Description
Data Category CTD or STD cast
Instrument Type
NameCategories
Sea-Bird SBE 13 Dissolved Oxygen Sensor  dissolved gas sensors
Sea-Bird SBE 911plus CTD  CTD; water temperature sensor; salinity sensor
WETLabs ECO FL fluorometer  fluorometers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Mr Colin Griffiths
Originating Organization Scottish Association for Marine Science
Processing Status banked
Project(s) Northern Seas Programme (NSP)
Northern Seas Programme (NSP) - Theme B
 

Data Identifiers

Originator's Identifier P300_015
BODC Series Reference 845027
 

Time Co-ordinates(UT)
Start Time (yyyy-mm-dd hh:mm) 2003-07-23 18:20
End Time (yyyy-mm-dd hh:mm) 2003-07-23 20:05
Nominal Cycle Interval 2.0 decibars
 

Spatial Co-ordinates

Latitude 57.14935 N ( 57° 9.0' N )
Longitude 9.70172 W ( 9° 42.1' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 6.0 m
Maximum Sensor Depth 1934.0 m
Minimum Sensor Height 0.0 m
Maximum Sensor Height 1928.0 m
Sea Floor Depth 1934.0 m
Sensor Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters
BODC CODE Rank Units Title
ACYCAA01 1 Dimensionless Sequence number
CPHLPM01 1 Milligrams per cubic metre Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate phase] by in-situ chlorophyll fluorometer and manufacturer's calibration applied
DOXYPR01 1 Micromoles per litre Concentration of oxygen {O2} per unit volume of the water body [dissolved phase] by in-situ Beckmann probe
PRESPR01 1 Decibars Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level
PSALCC01 1 Dimensionless Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and calibration against independent measurements
TEMPCU01 1 Degrees Celsius Temperature of the water body by CTD and NO verification against independent measurements
 

Definition of Rank
  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

Problem Reports

The oxygen sensor data for this series are considered suspect by the data originator.

Data Access Policy

Public domain 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.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."

Narrative Documents

Sea Bird Electronics SBE13 Dissolved Oxygen Sensor

The SBE 13 was designed as an auxiliary sensor for Sea Bird SBE 9plus, but can fitted in custom instrumentation applications. When used with the SBE 9 Underwater Unit, a flow-through plenum improves the data quality, as the pumping water over the sensor membrane reduces the errors caused by oxygen depletion during the periods of slow or intermittent flushing and also reduces exposure to biofouling.

The output voltage is proportional to membrane current (oxygen current) and to the sensor element's membrane temperature (oxygen temperature), which is used for internal temperature compensation.

Two versions of the SBE 13 are available: the SBE 13Y uses a YSI polarographic element with replaceable membranes to provide in situ measurements up to 2000 m depth and the SBE 13B uses a Beckman polarographic element to provide in situ measurements up to 10500 m depth, depending on the sensor casing. This sensor includes a replaceable sealed electrolyte membrane cartridge.

The SBE 13 instrument has been out of production since 2001 and has been superseded by the SBE 43.

Specifications

Measurement range 0 to 15 mL L-1
Accuracy 0.1 mL L-1
Time response

2 s at 25°C

5 s at 0°C
Depth range

2000 m (SBE 13Y- housing in anodized aluminum)

6800 m (SBE 13B- housing in anodized aluminum)

105000 m (SBE 13B- housing in titanium)

Further details can be found in the manufacturer's specification sheet.

PO300_2 Kiel CTD Instrumentation

CTD unit and auxiliary sensors

The first 16 CTD casts were performed with a Kiel Sea-Bird 911 plus CTD system. The rosette was fitted with 22 * 10L Niskin bottles, bottle 3 and 4 were missing due to a bracket having been fitted onto the frame. This CTD system was used between the 20th July and the 24th July 2003.

The CTD was fitted with the following scientific sensors:

Sensor Serial Number Last calibration date
Pressure - Digiquartz 82991 18 December 2000
Temperature 4051 12 January 2001
Conductivity 2537 30 January 2001
Fluorometer - Wetlab ECO-AFL/FL - -
Oxygen - Beckman/YSI probe 130555 6 May 2000

The salinity samples from the CTD were analysed during the cruise in a constant temperature laboratory using a bench top salinometer.

Sea-Bird Electronics SBE 911 and SBE 917 series CTD profilers

The SBE 911 and SBE 917 series of conductivity-temperature-depth (CTD) units are used to collect hydrographic profiles, including temperature, conductivity and pressure as standard. Each profiler consists of an underwater unit and deck unit or SEARAM. Auxiliary sensors, such as fluorometers, dissolved oxygen sensors and transmissometers, and carousel water samplers are commonly added to the underwater unit.

Underwater unit

The CTD underwater unit (SBE 9 or SBE 9 plus) comprises a protective cage (usually with a carousel water sampler), including a main pressure housing containing power supplies, acquisition electronics, telemetry circuitry, and a suite of modular sensors. The original SBE 9 incorporated Sea-Bird's standard modular SBE 3 temperature sensor and SBE 4 conductivity sensor, and a Paroscientific Digiquartz pressure sensor. The conductivity cell was connected to a pump-fed plastic tubing circuit that could include auxiliary sensors. Each SBE 9 unit was custom built to individual specification. The SBE 9 was replaced in 1997 by an off-the-shelf version, termed the SBE 9 plus, that incorporated the SBE 3 plus (or SBE 3P) temperature sensor, SBE 4C conductivity sensor and a Paroscientific Digiquartz pressure sensor. Sensors could be connected to a pump-fed plastic tubing circuit or stand-alone.

Temperature, conductivity and pressure sensors

The conductivity, temperature, and pressure sensors supplied with Sea-Bird CTD systems have outputs in the form of variable frequencies, which are measured using high-speed parallel counters. The resulting count totals are converted to numeric representations of the original frequencies, which bear a direct relationship to temperature, conductivity or pressure. Sampling frequencies for these sensors are typically set at 24 Hz.

The temperature sensing element is a glass-coated thermistor bead, pressure-protected inside a stainless steel tube, while the conductivity sensing element is a cylindrical, flow-through, borosilicate glass cell with three internal platinum electrodes. Thermistor resistance or conductivity cell resistance, respectively, is the controlling element in an optimized Wien Bridge oscillator circuit, which produces a frequency output that can be converted to a temperature or conductivity reading. These sensors are available with depth ratings of 6800 m (aluminium housing) or 10500 m (titanium housing). The Paroscientific Digiquartz pressure sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.

Additional sensors

Optional sensors for dissolved oxygen, pH, light transmission, fluorescence and others do not require the very high levels of resolution needed in the primary CTD channels, nor do these sensors generally offer variable frequency outputs. Accordingly, signals from the auxiliary sensors are acquired using a conventional voltage-input multiplexed A/D converter (optional). Some Sea-Bird CTDs use a strain gauge pressure sensor (Senso-Metrics) in which case their pressure output data is in the same form as that from the auxiliary sensors as described above.

Deck unit or SEARAM

Each underwater unit is connected to a power supply and data logging system: the SBE 11 (or SBE 11 plus) deck unit allows real-time interfacing between the deck and the underwater unit via a conductive wire, while the submersible SBE 17 (or SBE 17 plus) SEARAM plugs directly into the underwater unit and data are downloaded on recovery of the CTD. The combination of SBE 9 and SBE 17 or SBE 11 are termed SBE 917 or SBE 911, respectively, while the combinations of SBE 9 plus and SBE 17 plus or SBE 11 plus are termed SBE 917 plus or SBE 911 plus.

Specifications

Specifications for the SBE 9 plus underwater unit are listed below:

Parameter Range Initial accuracy Resolution at 24 Hz Response time
Temperature -5 to 35°C 0.001°C 0.0002°C 0.065 sec
Conductivity 0 to 7 S m-1 0.0003 S m-1 0.00004 S m-1 0.065 sec (pumped)
Pressure 0 to full scale (1400, 2000, 4200, 6800 or 10500 m) 0.015% of full scale 0.001% of full scale 0.015 sec

Further details can be found in the manufacturer's specification sheet.

WETLabs ECO-FL Fluorometer

The Environmental Characterization Optics series of single channel fluorometers are designed to measure concentrations of natural and synthetic substances in water, and are therefore useful for biological monitoring and dye trace studies. Selected excitation and emission filters allow detection of the following substances: chlorophyll-a, coloured dissolved organic matter (CDOM), uranine (fluorescein), rhodamine, phycoerythrin and phycocyanin.

The ECO-FL can operate continuously or periodically and has two different types of connectors to output the data (analogue and RS-232 serial output). The potted optics block results in long term stability of the instrument and the optional anti-biofouling technology delivers truly long term field measurements.

In addition to the standard model, five variants are available, and the differences between these and the basic ECO-FL are listed below:

Specifications

Temperature range 0 to 30°C
Depth rating

600 m (standard)

6000 m (deep)
Linearity 99 % R2
Chlorophyll-a
Wavelength (excitation/emission) 470/695 nm
Sensitivity 0.01 µg L-1
Typical range 0.01 to 125 µg L-1
CDOM
Wavelength (excitation/emission) 370/460 nm
Sensitivity 0.01 ppb
Typical range 0.09 to 500 ppb
Uranine
Wavelength (excitation/emission) 470/530 nm
Sensitivity 0.07 ppb
Typical range 0.12 to 230 ppb
Rhodamine
Wavelength (excitation/emission) 540/570 nm
Sensitivity 0.01 ppb
Typical range 0.01 to 230 ppb
Phycoerythrin
Wavelength (excitation/emission) 540/570 nm
Sensitivity 0.01 ppb
Typical range 0.01 to 230 ppb
Phycocyanin
Wavelength (excitation/emission) 630/680 nm
Sensitivity 0.15 ppt
Typical range 0.15 to 400 ppt

Further details can be found in the manufacturer's specification sheet.

PO300_2 CTD Processing undertaken by BODC

The CTD data obtained with the SAMS CTD frame were supplied to BODC in the form of 82 ASCII, WHP (WOCE Hydrographic Program) standard files bin-averaged to 2 dbar.

24 Hz ASCII versions of these data are also available from BODC, upon request. These files are held in their original format and, although containing additional parameters, have undergone less quality control and remain uncalibrated.

The submitted WHP standard casts were transferred to BODC's internal QXF format using Matlab. During transfer the originator's variables are mapped to unique BODC parameter codes. The mapping can be seen below.

Originator Variable Description Units BODC Parameter Code Units Comments
CTDTMP Temperature of water column deg C TEMPCU01 deg C -
CTDPRS Pressure exerted by the water column dbar PRESPR01 dbar -
FLUOR Concentration of Chlorophyll-a per unit volume of the water column mg m-3 CPHLPM01 mg m-3 Available in both 2 dbar and 24 Hz files
CTDSAL Practical salinity of the water column - PSALCC01 - Calibrated using discrete samples.
CTDOXY Concentration of dissolved oxygen per unit volume of the water column µmol kg-1 DOXYSU01 µmol l-1 Uncalibrated. Unit conversion performed by BODC transfer.

The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, and missing data marked by both setting the data to an appropriate value and setting the quality control flag.

PO300_2 Kiel CTD Originator Processing

Sampling strategy

A total of 82 CTD casts were performed during the cruise. The first 16 CTD casts undertaken were performed using Poseidon's CTD frame (belonging to Kiel), which was fitted with a SAMS fluorometer. Bottle samples were taken on each deployment upcast. These were used to calibrate the CTD conductivity sensor and also to obtain samples for analysis of chlorophyll a, POC, PON and nutrients.

Data processing

Following the completion of each CTD cast the data were saved to the deck unit PC and transferred over the network to a Unix data disk. SBE Seasave Win32 V 5.35 software was used to perform all processing steps.

Raw data files were converted to engineering units and binary .CNV files using the DATCNV program. Sea-Bird bottle data files (.BTL), with information on pressure and other readings logged at the time of bottle firing, were also generated during the data conversion process. The WILDEDIT program was run to remove any large pressure spikes and then the SeaSoft program ALIGNCTD was run to advance the oxygen measurements by 3 seconds ensuring the calculations of dissolved oxygen concentration are made using measurements from the same parcel of water. CELLTM was run, according to Sea-Bird's recommendations, to remove conductivity cell thermal mass effects from the measured conductivity and FILTER was run on the pressure channel using a low-pass filter value of 0.2 to smooth the rapidly changing data. Finally, salinity, density and depth were calculated using the DERIVE program and TRANSLATE wrote the data to an ASCII output .CNV file. Despiking of the pressure, oxygen, temperature and salinity data was carried out by visualising the data in MATLAB. If a spike occurs in pressure, temperature or salinity the whole corresponding scan is deleted. If the spike occurs in the other channels, the value is set to NaN and all remaining channels are left unedited. Following despiking of the data in MATLAB the module BINAVERAGE averaged the 24 Hz data into 2db-bins, using the downcast data only.

More information on the processing steps can be found in the SAMS Sea-Bird processing document.

Calibration

The salinity data from the CTD were calibrated using independent values obtained from the CTD water bottles. The calibration equation is:

Salinitycalibrated = 0.9947 * Salinityuncalibrated + 0.2029

with a correlation coefficient (R2) of 0.9995

Project Information

Northern Seas Programme

The Northern Seas describes an area extending from the Irish and northern North Sea across the Norwegian Sea up to the marginal Arctic pack-ice zone, including territorial waters of the UK, Norway, Iceland, Denmark and Russia. These waters are an important marine environment playing a significant part in regulating world climate due to the area's role in thermocline circulation in addition to acting as a sink for man-made pollutants carried north by ocean currents. These environments are experiencing increasing pressures from both natural and human impacts and consequently the Northern Seas Programme was developed to help advance the understanding of how marine systems in Northern Seas respond to environmental and anthropogenic change.

Scientific Objectives

The central aim of the programme was to 'improve understanding of how the sensitivity of marine ecosystems to environmental perturbation, both natural and anthropogenic, varies along a latitudinal gradient'.

This aim was addressed through the following integrated themes:

Theme A: Understanding fjordic systems: insights for coastal and oceanic processes

Theme B: Ocean Margins: the interface between the coastal zone and oceanic realm

Theme C: Measuring and modelling change: sea sensors and bioinformatics

The Northern Seas Programme was active between 2001 and 2007. The fieldwork programme to address these objectives was conducted by staff from the Scottish Association for Marine Science (SAMS).

Northern Seas Programme Theme B

Theme B: Ocean Margins: the interface between the coastal zone and oceanic realm

The interface between coastal and oceanic realms at the ocean margins has been addressed through the following sub-themes:

Sub Theme B1: Carbon dynamics at ocean margins

Sub Theme B2: The Ellett Line time series

Sub Theme B3: The ecology of deep-water fisheries of the Northern Rockall Trough

Data Activity or Cruise Information

Cruise

Cruise Name PO300_2
Departure Date 2003-07-19
Arrival Date 2003-08-06
Principal Scientist(s)Colin R Griffiths (Scottish Association for Marine Science)
Ship FS Poseidon

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Station NameExtended Ellett Line
CategoryOffshore route/traverse

Extended Ellett Line

The Extended Ellett Line is a hydrographic transect consisting of 58 individual fixed stations which have been occupied, typically on an annual basis, since September 1996. The Line runs from the south of Iceland, across the Iceland Basin to the outcrop of Rockall, and across the Rockall Trough to the north west coast of Scotland (see map). CTD dips and associated water sampling for the analysis of nutrients are routinely performed during each station occupation.

The Extended Ellett Line augments the original Ellett Line time series - a shorter repeated transect which encompassed those stations between Rockall and Scotland. Work on the Ellett Line was typically carried out at least once a year between 1975 and 1996.

Map of standard stations (1996-present)

BODC image

Map produced using the GEBCO Digital Atlas

The white triangles indicate the nominal positions of the Extended Ellett Line stations visited since September 1996. Measurements made along the Extended Ellett Line lie within a box bounded by co-ordinates 56° N, 21° W at the south west corner and 65° N, 6° W at the north east corner.

Nominal Extended Ellett Line stations (September 1996-present)

Listed below are nominal details of the standard hydrographic stations that have formed the Extended Ellett Line since September 1996.

Station Latitude Longitude Depth Range
IB23S 63.318 N 20.210 W 125 m -
IB22S 63.217 N 20.067 W 660 m 0.0 nm
IB21S 63.133 N 19.917 W 1030 m 6.5 nm
IB20S 62.917 N 19.550 W 1415 m 16.4 nm
IB19S 62.667 N 19.667 W 1500 m 16.0 nm
IB18S 62.333 N 19.833 W 1800 m 16.0 nm
IB17 62.000 N 20.000 W 1700 m 20.6 nm
IB16 61.500 N 20.000 W 2000 m 30.1 nm
IB15 61.250 N 20.000 W 2375 m 15.0 nm
IB14 61.000 N 20.000 W 2400 m 15.0 nm
IB13 60.500 N 20.000 W 2500 m 30.1 nm
IB12 60.000 N 20.000 W 2700 m 30.1 nm
IB11 59.667 N 19.117 W 2680 m 33.3 nm
IB10 59.400 N 18.417 W 2420 m 26.7 nm
IB9 59.333 N 18.233 W 1910 m 6.9 nm
IB8 59.200 N 17.883 W 1540 m 13.4 nm
IB7 59.117 N 17.667 W 1000 m 8.3 nm
IB6 58.950 N 17.183 W 850 m 18.0 nm
IB5 58.883 N 17.000 W 1150 m 7.0 nm
IB4 58.500 N 16.000 W 1210 m 38.8 nm
IB3 58.250 N 15.333 W 680 m 25.8 nm
IB2 57.950 N 14.583 W 480 m 29.9 nm
IB1 57.667 N 13.900 W 160 m 27.7 nm
A 57.583 N 13.633 W 130 m 10.0 nm
B 57.567 N 13.333 W 210 m 9.7 nm
C 57.550 N 13.000 W 330 m 10.8 nm
D 57.542 N 12.867 W 1000 m 4.3 nm
E 57.533 N 12.633 W 1658 m 7.6 nm
F 57.508 N 12.250 W 1817 m 12.5 nm
G 57.492 N 11.850 W 1812 m 13.0 nm
H 57.483 N 11.533 W 2020 m 10.3 nm
I 57.467 N 11.317 W 750 m 7.0 nm
J 57.450 N 11.083 W 550 m 7.6 nm
K 57.400 N 10.867 W 850 m 7.6 nm
L 57.367 N 10.667 W 2076 m 6.8 nm
M 57.300 N 10.383 W 2340 m 10.1 nm
N 57.233 N 10.050 W 2100 m 11.5 nm
O 57.150 N 9.700 W 1900 m 12.4 nm
P 57.100 N 9.417 W 1050 m 9.7 nm
Q 57.050 N 9.217 W 350 m 7.2 nm
R 57.000 N 9.000 W 135 m 7.7 nm
S 56.950 N 8.783 W 125 m 7.7 nm
15G 56.883 N 8.500 W 125 m 10.1 nm
T 56.837 N 8.333 W 120 m 6.1 nm
14G 56.808 N 8.167 W 115 m 5.7 nm
13G 56.783 N 8.000 W 110 m 5.7 nm
12G 56.758 N 7.833 W 80 m 5.7 nm
11G 56.733 N 7.667 W 55 m 5.7 nm
10G 56.733 N 7.500 W 220 m 5.5 nm
9G 56.733 N 7.333 W 160 m 5.5 nm
8G 56.733 N 7.167 W 175 m 5.5 nm
7G 56.733 N 7.000 W 145 m 5.5 nm
6G 56.733 N 6.750 W 35 m 8.2 nm
5G 56.733 N 6.600 W 75 m 4.9 nm
4G 56.733 N 6.450 W 115 m 4.9 nm
3G 56.708 N 6.367 W 75 m 3.1 nm
2G 56.683 N 6.283 W 40 m 3.2 nm
1G 56.667 N 6.133 W 190 m 5.0 nm

Occupations of the Extended Ellett Line (September 1996-present)

BODC Cruise Identifier Cruise Dates Ship
D223A 28 September-21 October 1996 RRS Discovery
D230 7 August-17 September 1997 RRS Discovery
D233 23 April-1 June 1998 RRS Discovery
D242 7 September-6 October 1999 RRS Discovery
D245 * 27 January-20 February 2000 RRS Discovery
0700S * 8-22 May 2000 FRV Scotia
D253 4 May-20 June 2001 RRS Discovery
0703S * 15 April-5 May 2003 FRV Scotia
PO300_2 * 19 July-6 August 2003 RRS Poseidon
PO314 11 July-23 July 2004 RV Poseidon
CD176 6 October-1 November 2005 RRS Charles Darwin
D312 11-31 October 2006 RRS Discovery
D321A 24 July-23 August 2007 RRS Discovery
D321B 24 August-9 September 2007 RRS Discovery
0508S * 6-25 May 2008 FRV Scotia
D340A 10-25 June 2009 RRS Discovery
D351 10-28 May 2010 RRS Discovery
D365 13 May-02 June 2011 RRS Discovery

* These cruises only surveyed the original hydrographic section between Scotland and Rockall.

Other Series linked to this Fixed Station for this cruise - 844872 844884 844896 844903 844915 844927 844939 844940 844952 844964 844976 844988 845003 845015 845040 845064 845088 845107 845119 845120 845132 845144 845156 845168 845181 845193 845200 845212 845224 845236

Other Cruises linked to this Fixed Station (with the number of series) - 0508S (29) 0700S (20) 0703S (20) CD176 (40) D233 (25) D242 (45) D245 (25) D312 (51) D321 (D321A) (12) D321B (59) D340A (58) D351 (23) PO300_2 (30)

Fixed Station Information

Station NameEllett Line/Extended Ellett Line Station O
CategoryOffshore location
Latitude57° 9.00' N
Longitude9° 42.00' W
Water depth below MSL1900.0 m

Ellett Line/Extended Ellett Line: Station O

Station O is one of 58 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 O 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.

Other Cruises linked to this Fixed Station (with the number of series) - 0508S (1) 0700S (1) 0703S (1) CD176 (1) CD44 (1) CD92B (2) CH10/81 (1) CH103 (2) CH105 (1) CH10A/75 (1) CH11/77 (1) CH11/83 (1) CH110 (1) CH112 (2) CH114 (1) CH116 (1) CH11B/78 (1) CH11D/78 (1) CH120 (1) CH124 (1) CH13/77 (1) CH13/79 (1) CH14 (1) CH14A/75 (1) CH15/81 (1) CH16/79 (1) CH2/78 (1) CH2/81 (1) CH25 (1) CH30 (1) CH4/80 (2) CH4/85 (1) CH5A/76 (1) CH67A (1) CH6A/81 (1) CH6B/77 (1) CH6B/81 (1) CH7/79 (1) CH7/80 (1) CH71A (1) CH75B (1) CH7A/75 (1) CH7A/82 (1) CH7B/83 (2) CH8/76 (1) CH8/85 (1) CH81 (1) CH9 (1) CH9/78 (1) CH97 (1) D180 (1) D233 (1) D242 (2) D245 (1) D312 (1) D321B (1) D340A (1) D351 (1) LF1/89 (1) LF2/89 (1)

Fixed Station Information

Station NameEllett Line
CategoryOffshore route/traverse

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)

BODC image

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.

Station Latitude Longitude Depth Range
A 57.583 N 13.633 W 130 m 10.0 nm
B 57.567 N 13.333 W 210 m 9.7 nm
C 57.550 N 13.000 W 330 m 10.8 nm
D 57.542 N 12.867 W 1000 m 4.3 nm
E 57.533 N 12.633 W 1658 m 7.6 nm
F 57.508 N 12.250 W 1817 m 12.5 nm
G 57.492 N 11.850 W 1812 m 13.0 nm
H 57.483 N 11.533 W 2020 m 10.3 nm
I 57.467 N 11.317 W 750 m 7.0 nm
J 57.450 N 11.083 W 550 m 7.6 nm
K 57.400 N 10.867 W 850 m 7.6 nm
L 57.367 N 10.667 W 2076 m 6.8 nm
M 57.300 N 10.383 W 2340 m 10.1 nm
N 57.233 N 10.050 W 2100 m 11.5 nm
O 57.150 N 9.700 W 1900 m 12.4 nm
P 57.100 N 9.417 W 1050 m 9.7 nm
Q 57.050 N 9.217 W 350 m 7.2 nm
R 57.000 N 9.000 W 135 m 7.7 nm
S 56.950 N 8.783 W 125 m 7.7 nm
15G 56.883 N 8.500 W 125 m 10.1 nm
T 56.837 N 8.333 W 120 m 6.1 nm
14G 56.808 N 8.167 W 115 m 5.7 nm
13G 56.783 N 8.000 W 110 m 5.7 nm
12G 56.758 N 7.833 W 80 m 5.7 nm
11G 56.733 N 7.667 W 55 m 5.7 nm
10G 56.733 N 7.500 W 220 m 5.5 nm
9G 56.733 N 7.333 W 160 m 5.5 nm
8G 56.733 N 7.167 W 175 m 5.5 nm
7G 56.733 N 7.000 W 145 m 5.5 nm
6G 56.733 N 6.750 W 35 m 8.2 nm
5G 56.733 N 6.600 W 75 m 4.9 nm
4G 56.733 N 6.450 W 115 m 4.9 nm
3G 56.708 N 6.367 W 75 m 3.1 nm
2G 56.683 N 6.283 W 40 m 3.2 nm
1G 56.667 N 6.133 W 190 m 5.0 nm

History of Ellett Line occupations (1975-January 1996)

BODC Cruise Identifier Cruise Dates Ship
CH3/75 4-13 March 1975 RRS Challenger
CH7A/75 1-6 May 1975 RRS Challenger
CH10A/75 4-10 July 1975 RRS Challenger
CH12A/75 26 August-2 September 1975 RRS Challenger
CH14A/75 7-12 November 1975 RRS Challenger
CH5A/76 29 March-5 April 1976 RRS Challenger
CH8/76 19 May-1 June 1976 RRS Challenger
CH12/76 4-15 August 1976 RRS Challenger
CH15/76 7-16 October 1976 RRS Challenger
CH17/76 7-20 December 1976 RRS Challenger
CH4/77 25 February-11 March 1977 RRS Challenger
CH6B/77 14-19 April 1977 RRS Challenger
CH10/77 29 June-10 July 1977 RRS Challenger
CH11/77 12-26 July 1977 RRS Challenger
CH13/77 20 August-3 September 1977 RRS Challenger
CH2/78 30 January-13 February 1978 RRS Challenger
CH6/78 11-21 April 1978 RRS Challenger
CH9/78 31 May-10 June 1978 RRS Challenger
CH11B/78 29 July-12 August 1978 RRS Challenger
CH11D/78 3-17 September 1978 RRS Challenger
CH14B/78 4-11 November 1978 RRS Challenger
CH7/79 10-23 May 1979 RRS Challenger
S5/79 19 June-2 July 1979 RRS Shackleton
CH13/79 11-16 September 1979 RRS Challenger
CH16/79 28 October-11 November 1979 RRS Challenger
CH4/80 26 February-7 March 1980 RRS Challenger
CH7/80 21 April-6 May 1980 RRS Challenger
CH2/81 26 January-4 February 1981 RRS Challenger
CH6A/81 CH6B/81 6-25 April 1981 RRS Challenger
CH10/81 4-14 July 1981 RRS Challenger
CH15/81 6-20 October 1981 RRS Challenger
CH7A/82 CH7B/82 26 April-16 May 1982 RRS Challenger
CH15/82 16-30 October 1982 RRS Challenger
CH7B/83 23 May-2 June 1983 RRS Challenger
CH11/83 10-24 August 1983 RRS Challenger
CH2/84 23 June-8 July 1984 RRS Challenger
CH10/84 16 November-6 December 1984 RRS Challenger
CH1/85 20 January-5 February 1985 RRS Challenger
CH4/85 2-16 May 1985 RRS Challenger
CH8/85 14-28 August 1985 RRS Challenger
CH9 8-22 January 1987 RRS Challenger
CH14 24 April-7 May 1987 RRS Challenger
CH22 23 November-5 December 1987 RRS Challenger
CH25 24 February-7 March 1988 RRS Challenger
CH30 6-23 June 1988 RRS Challenger
D180 20 January-4 February 1989 RRS Discovery
LF1/89 5-11 May 1989 RV Lough Foyle
LF2/89 4-10 August 1989 RV Lough Foyle
CD44 24 November-2 December 1989 RRS Charles Darwin
CH67A 21-29 June 1990 RRS Challenger
CH71A 29 August-5 September 1990 RRS Challenger
CH75B 23 February-3 March 1991 RRS Challenger
CH81 1-8 July 1991 RRS Challenger
CH97 25 September-6 October 1992 RRS Challenger
CH101B 13-20 March 1993 RRS Challenger
CH103 12-24 May 1993 RRS Challenger
CH105 3-16 September 1993 RRS Challenger
CH110 10-20 March 1994 RRS Challenger
CH112 28 April-13 May 1994 RRS Challenger
CH114 15-29 August 1994 RRS Challenger
CH116 17-29 November 1994 RRS Challenger
CD92B 13 April-2 May 1995 RRS Charles Darwin
CH120 18 July-6 August 1995 RRS Challenger
CH124 8-27 January 1996 RRS Challenger

Other Series linked to this Fixed Station for this cruise - 844872 844884 844896 844903 844915 844927 844939 844940 844952 844964 844976 844988 845003 845015 845040 845064 845088 845107 845119 845120 845132 845144 845156 845168 845181 845193 845200 845212 845224 845236

Other Cruises linked to this Fixed Station (with the number of series) - 0508S (29) 0700S (20) 0703S (20) CD176 (32) CD44 (34) CD92B (47) CH1/85 (19) CH10/77 (3) CH10/81 (21) CH10/84 (22) CH101B (13) CH103 (37) CH105 (34) CH10A/75 (15) CH11/77 (28) CH11/83 (35) CH110 (19) CH112 (35) CH114 (31) CH116 (25) CH11B/78 (26) CH11D/78 (14) CH120 (28) CH124 (32) CH12A/75 (3) CH13/77 (19) CH13/79 (17) CH14 (29) CH14A/75 (21) CH14B/78 (17) CH15/80 (8) CH15/81 (16) CH16/79 (13) CH2/78 (32) CH2/81 (13) CH2/82 (4) CH2/84 (29) CH22 (14) CH25 (18) CH3/83 (1) CH30 (23) CH4/77 (19) CH4/80 (29) CH4/85 (30) CH5A/76 (18) CH6/78 (25) CH63_2 (5) CH67A (27) CH6A/81 (14) CH6B/77 (24) CH6B/81 (20) CH7/79 (18) CH7/80 (16) CH71A (32) CH74A_1 (13) CH75B (31) CH7A/75 (24) CH7A/82 (24) CH7B/82 (13) CH7B/83 (29) CH8/76 (27) CH8/85 (30) CH81 (30) CH86B (8) CH89B (9) CH9 (25) CH9/78 (22) CH97 (30) CH9B/80 (10) D180 (30) D233 (10) D242 (23) D245 (25) D312 (34) D321B (35) D340A (34) D351 (34) DSK1/86 (10) FR13/85 (12) FR13/87 (2) FR14B/87 (2) FR18/87 (11) FR7B/86 (6) FR8/86 (13) LF1/89 (29) LF2/89 (30) PO300_2 (30) S5/79 (8)

BODC Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
Blank Unqualified
< Below detection limit
> In excess of quoted value
A Taxonomic flag for affinis (aff.)
B Beginning of CTD Down/Up Cast
C Taxonomic flag for confer (cf.)
D Thermometric depth
E End of CTD Down/Up Cast
G Non-taxonomic biological characteristic uncertainty
H Extrapolated value
I Taxonomic flag for single species (sp.)
K Improbable value - unknown quality control source
L Improbable value - originator's quality control
M Improbable value - BODC quality control
N Null value
O Improbable value - user quality control
P Trace/calm
Q Indeterminate
R Replacement value
S Estimated value
T Interpolated value
U Uncalibrated
W Control value
X Excessive difference