RRS Challenger CH121C

Cruise summary report

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Cruise Info.

Ship name (ship code)

RRS Challenger (74CH)

Cruise identifier

CH121C

Cruise period

1995-09-01 — 1995-09-10

Status

Completed

Port of departure

Mallaig, United Kingdom

Port of return

Southampton, United Kingdom

Purpose

Research

Objectives

CH121 was the second of six cruises under the LOIS Shelf Edge Study (SES) aimed at defining the nature of the processes occurring at the shelf edge, their seasonal variability and their impact on the fluxes of nutrients and carbon across the shelf and into the seabed sediments through the shelf.
The cruise was divided into three legs with the first and third being principally directed to the deployment and recovery of an extensive mooring array and the acquisition of sediment cores from selected sites in the SES area. The second leg had a series of objectives concerned with measuring the water column structure and velocity field in the shelf edge regime. To complement the time series data from the moored array of current meters and thermistor chains, the cruise plan called for measurements by shipboard adcp and CTD together to help identify the motions associated with internal tides and waves. These motions, which are generated at the shelf edge, may contribute to turbulent mixing and dissipation and the distribution of the latter was to be investigated with the aid of the FLY free-fall turbulence probe which was to be investigated. More wide-ranging spatial measurements were required to demonstrate the continuity of the slope current and to investigate its cross slope structure.
While this cruise was principally concerned with the physics of the shelf edge system, the programme was also designed to obtain an extensive set of measurements of chlorophyll a, primary production and nutrient concentrations in parallel with physical observations. A further goal was to acquire surficial sediment material from a number of sites down the slope.

Chief scientist

John H Simpson (University of Wales, Bangor School of Ocean Sciences)

Project

LOIS - SES

Coordinating body

UK NERC/Proudman Oceanographic Laboratory (POL)

Cruise report

(1.92 MB)

Ocean/sea areas

General

North East Atlantic Ocean (limit 40W)

Specific

NE Atlantic, Malin Shelf Break (60nm west of Hebrides)

Track charts

Measurements

Physical oceanography

Surface measurements underway (T,S)

Quantity: track kilometres = 500
Description: surface underway measurements

CTD stations

Quantity: number of profiles = 32
Description: CTD plus transmissometer,fluorometer,O2 sensors,PAR sensors

Transparency (eg transmissometer)

Quantity: number of profiles = 32
Description: on CTD

Transparency (eg transmissometer)

Quantity: track kilometres = 500
Description: surface underway measurements

Optics (eg underwater light levels)

Quantity: number of profiles = 32
Description: on CTD

Optics (eg underwater light levels)

Quantity: track kilometres = 500
Description: surface underway measurements

Current meters

Quantity: number of recoveries = 7

Current profiler (eg ADCP)

Quantity: track kilometres = 500
Description: shipborne ADCP

Chemical oceanography

Oxygen

Quantity: number of profiles = 32
Description: on CTD

Contamination

Suspended matter

Quantity: number of samples = 42
Description: 2 sediment traps deployed at 56 43.5N, 9 24.3W (redeployed)

Biology and fisheries

Phytoplankton pigs (eg chlorophyll, fluorescence)

Quantity: number of profiles = 32
Description: on CTD

Phytoplankton pigs (eg chlorophyll, fluorescence)

Quantity: number of samples = 64
Description: bottle samples for chlorophyll determination

Phytoplankton pigs (eg chlorophyll, fluorescence)

Quantity: track kilometres = 500
Description: surface underway measurements

Geology and geophysics

Core - soft bottom

Quantity: number of deployments = 9
Description: 8 multi- & 1 Sholkovitz core for bio- & geochemical analysis

Moorings, landers, buoys

Physical oceanography

Current meters

56° 43' 36" N 9° 24' 11" W — Site N1500 recovered, current meter/transmissometer, sediment trapr

Current meters

56° 26' 42" N 9° 3' 6" W — S400 site recovered, ADCP and STABLE

Current meters

56° 27' 36" N 9° 3' 36" W — Site S300, recovered, redeployed- and lost a few days later

Current meters

56° 27' 6" N 9° 4' 48" W — Site S400, recover/redeploy pop-up ADCP, recover pop-up current meter

Current meters

56° 28' 23" N 9° 9' 53" W — Site S700, recovered

Current meters

56° 37' 23" N 9° 1' 30" W — Site N300 recovered

Current meters

56° 27' 47" N 8° 57' 47" W — Site S140, deployed

Surface drifters/drifting buoys

56° 27' 47" N 9° 7' 54" W — subsurface drogue (surface/subsurface temperature), deployed

Other physical oceanographic measurements

56° 27' 36" N 8° 58' 0" W — acoustic study of bubble entrapment (ARIES II) recovery

Biology and fisheries

Phytoplankton pigs (eg chlorophyll, fluorescence)

56° 29' 53" N 9° 2' 35" W — toroid buoy with nitrate analysers and fluorometers

Phytoplankton pigs (eg chlorophyll, fluorescence)

56° 28' 0" N 8° 52' 36" W — toroid buoy with nitrate analysers and fluorometers

Data held at BODC

Get data

Series/Profiles

1 Accelerometer-waverider buoy

Date and time
Wave height and period statistics

[Show series]

Date and time
Wave height and period statistics

[Hide series]

BODC id	Date/Time	Location	Doc.
507815	1995-09-05 18:00 — 1995-11-07 06:00	56° 27' 28" N 8° 58' 13" W

2 Acoustic doppler current profiler

Date and time
Vertical spatial coordinates
Vertical velocity of the water column (currents)
Horizontal velocity of the water column (currents)
Metadata parameters

[Show series]

Date and time
Vertical spatial coordinates
Vertical velocity of the water column (currents)
Horizontal velocity of the water column (currents)
Metadata parameters

[Hide series]

BODC id	Date/Time	Location	Doc.
444197	1995-09-04 18:34:59 — 1995-11-19 09:05	56° 27' 49" N 8° 57' 59" W
444253	1995-09-06 07:55 — 1995-11-27 08:15	56° 27' 11" N 9° 4' 50" W

25 Bottle station

Reference numbers
Vertical spatial coordinates
Phaeopigment concentrations in the water column
Quality control flags
Chlorophyll pigment concentrations in water bodies

[Show series]

Reference numbers
Vertical spatial coordinates
Phaeopigment concentrations in the water column
Quality control flags
Chlorophyll pigment concentrations in water bodies

[Hide series]

BODC id	Date/Time	Location
1687542	1995-09-04 15:44	56° 27' 52" N 8° 57' 48" W
1687425	1995-09-02 17:15	56° 27' 2" N 9° 4' 27" W
1687474	1995-09-03 20:49	56° 29' 56" N 8° 56' 2" W
1687498	1995-09-03 22:29	56° 30' 20" N 9° 3' 41" W
1687591	1995-09-06 01:40	56° 27' 29" N 9° 39' 0" W
1687610	1995-09-07 00:24	56° 37' 13" N 9° 0' 33" W
1687437	1995-09-03 02:59	56° 27' 38" N 9° 18' 0" W
1687517	1995-09-04 00:29	56° 30' 54" N 9° 11' 5" W
1687529	1995-09-04 01:49	56° 31' 6" N 9° 18' 1" W
1687530	1995-09-04 08:01	56° 43' 47" N 9° 25' 50" W
1687566	1995-09-05 03:44	56° 40' 24" N 9° 11' 43" W
1687609	1995-09-06 05:33	56° 36' 16" N 9° 17' 12" W
1687658	1995-09-07 05:21	56° 33' 51" N 9° 1' 55" W
1687486	1995-09-03 21:45	56° 30' 17" N 9° 2' 14" W
1687622	1995-09-07 02:25	56° 37' 37" N 9° 1' 31" W
1687646	1995-09-07 04:47	56° 34' 8" N 9° 3' 14" W
1687449	1995-09-03 07:41	56° 27' 10" N 9° 3' 47" W
1687554	1995-09-05 02:34	56° 38' 43" N 9° 6' 36" W
1687578	1995-09-05 09:02	56° 42' 46" N 9° 25' 39" W
1687634	1995-09-07 03:10	56° 38' 6" N 9° 3' 59" W
1687413	1995-09-02 14:23	56° 37' 28" N 9° 1' 28" W
1687450	1995-09-03 13:43	56° 27' 56" N 9° 8' 4" W
1687505	1995-09-03 23:27	56° 30' 34" N 9° 7' 5" W
1687401	1995-09-02 09:14	56° 27' 59" N 8° 58' 16" W
1687462	1995-09-03 19:35	56° 26' 48" N 9° 2' 16" W

1 Bottom pressure sensor tide gauge

Date and time
Temperature of the water column
Sea level

[Show series]

Date and time
Temperature of the water column
Sea level

[Hide series]

BODC id	Date/Time	Location	Doc.
442640	1995-09-04 18:30:21 — 1995-11-19 09:30:21	56° 27' 49" N 8° 57' 59" W

32 CTD/STD cast

Transmittance and attenuance of the water column
Salinity of the water column
Temperature of the water column
Vertical spatial coordinates
Visible waveband radiance and irradiance measurements in the water column
Density of the water column
Chlorophyll pigment concentrations in water bodies

[Show series]

[Hide series]

BODC id	Date/Time	Location
851900	1995-09-02 20:01	56° 28' 32" N 9° 9' 47" W
851997	1995-09-04 20:42	56° 31' 8" N 9° 17' 58" W
852024	1995-09-06 01:13	56° 27' 29" N 9° 39' 0" W
852189	1995-09-07 05:15	56° 33' 51" N 9° 1' 55" W
851856	1995-09-01 19:03	56° 49' 4" N 6° 39' 38" W
852000	1995-09-05 02:18	56° 38' 43" N 9° 6' 36" W
852128	1995-09-03 20:42	56° 29' 57" N 8° 56' 3" W
851948	1995-09-03 22:18	56° 30' 20" N 9° 3' 42" W
851973	1995-09-04 01:21	56° 31' 7" N 9° 18' 1" W
852073	1995-09-07 04:04	56° 33' 38" N 9° 0' 8" W
852097	1995-09-07 13:04	56° 34' 36" N 9° 6' 39" W
851868	1995-09-02 08:59	56° 28' 0" N 8° 58' 16" W
851881	1995-09-02 12:12	56° 28' 20" N 9° 5' 0" W
852012	1995-09-05 08:33	56° 42' 46" N 9° 25' 39" W
851961	1995-09-03 23:13	56° 30' 34" N 9° 7' 5" W
852036	1995-09-06 23:37	56° 36' 18" N 8° 55' 49" W
852048	1995-09-07 00:16	56° 37' 13" N 9° 0' 33" W
852104	1995-09-02 17:07	56° 27' 1" N 9° 4' 27" W
852208	1995-09-04 15:35	56° 27' 52" N 8° 57' 47" W
851985	1995-09-04 07:29	56° 43' 46" N 9° 25' 50" W
852177	1995-09-07 02:53	56° 38' 6" N 9° 4' 0" W
852190	1995-09-03 19:24	56° 26' 48" N 9° 2' 16" W
851893	1995-09-02 14:11	56° 37' 28" N 9° 1' 28" W
852061	1995-09-07 02:17	56° 37' 37" N 9° 1' 31" W
852116	1995-09-03 07:27	56° 27' 10" N 9° 3' 47" W
851912	1995-09-03 02:34	56° 27' 38" N 9° 18' 0" W
851924	1995-09-03 13:29	56° 27' 56" N 9° 8' 4" W
851936	1995-09-03 21:40	56° 30' 17" N 9° 2' 14" W
852085	1995-09-07 04:37	56° 34' 8" N 9° 3' 13" W
852141	1995-09-04 00:07	56° 30' 54" N 9° 11' 4" W
852153	1995-09-05 03:20	56° 40' 24" N 9° 11' 43" W
852165	1995-09-06 05:10	56° 36' 16" N 9° 17' 12" W

1 Fluorometers

Date and time
Raw fluorometer output
Chlorophyll pigment concentrations in water bodies

[Show series]

Date and time
Raw fluorometer output
Chlorophyll pigment concentrations in water bodies

[Hide series]

BODC id	Date/Time	Location	Doc.
476083	1995-09-04 17:02:56 — 1995-11-24 02:02:56	56° 27' 58" N 8° 57' 31" W

4 Paddle wheel current meter

Transmittance and attenuance of the water column
Moored instrument depth
Date and time
Salinity of the water column
Temperature of the water column
Horizontal velocity of the water column (currents)
Electrical conductivity of the water column

[Show series]

[Hide series]

BODC id	Date/Time	Location
431433	1995-09-03 11:15 — 1995-09-05 23:15	56° 27' 31" N 9° 3' 43" W
439379	1995-09-02 08:44 — 1995-11-19 12:14	56° 27' 42" N 8° 57' 51" W
436197	1995-09-02 09:15 — 1995-11-19 12:15	56° 27' 42" N 8° 57' 51" W
431365	1995-09-03 11:15 — 1995-09-05 23:15	56° 27' 31" N 9° 3' 43" W

1 Pumped water sample

Horizontal spatial co-ordinates
Date and time
Phaeopigment concentrations in the water column
Chlorophyll pigment concentrations in water bodies

[Show series]

Horizontal spatial co-ordinates
Date and time
Phaeopigment concentrations in the water column
Chlorophyll pigment concentrations in water bodies

[Hide series]

BODC id	Date/Time	Location	Doc.
1678538	1995-09-02 08:42 — 1995-09-07 07:30	56° 26' 47" N 9° 25' 49" W — 56° 43' 53" N 8° 55' 58" W

3 Thermistor chain

Date and time
Temperature of the water column
Vertical spatial coordinates

[Show series]

Date and time
Temperature of the water column
Vertical spatial coordinates

[Hide series]

BODC id	Date/Time	Location
439515	1995-09-02 09:00 — 1995-11-19 12:00	56° 27' 42" N 8° 57' 51" W
439748	1995-09-03 11:30 — 1995-09-05 23:00	56° 27' 31" N 9° 3' 43" W
439540	1995-09-03 11:30 — 1995-09-05 23:00	56° 27' 31" N 9° 3' 43" W

1 Transmissometer

Transmittance and attenuance of the water column
Date and time
Salinity of the water column
Temperature of the water column
Electrical conductivity of the water column

[Show series]

Transmittance and attenuance of the water column
Date and time
Salinity of the water column
Temperature of the water column
Electrical conductivity of the water column

[Hide series]

BODC id	Date/Time	Location	Doc.
496139	1995-09-04 16:12 — 1995-11-27 11:27	56° 27' 58" N 8° 57' 31" W

Discrete samples

32 CTD frame plus rosette sampler

Transmittance and attenuance of the water column
Particulate total and organic nitrogen concentrations in the water column
Salinity of the water column
Temperature of the water column
Visible waveband radiance and irradiance measurements in the water column
Density of the water column
Phaeopigment concentrations in the water column
Particulate total and organic carbon concentrations in the water column
Chlorophyll pigment concentrations in water bodies

1 Drifting Buoy

7 Instrument mooring

Concentration of silicon species in suspended particulate material
Other physical and chemical properties of suspended particulate material
Sedimentation flux of carbon, nitrogen or organic matter in the water column
Carbon concentrations in suspended particulate material
Nitrogen concentrations in suspended particulate material
Sedimentation flux of non-metallic inorganic species in the water column
Sedimentation flux quantification in the water column

8 Multicorer

Concentration of organic matter in sediments
Other fluxes between the bed and the water column
Stable isotopes in sediment
Sediment water content, porosity and surface area
Concentration of inorganic sulphur species in sediment

30 Sample taken from ship's non-toxic supply

Salinity of the water column
Phaeopigment concentrations in the water column
Chlorophyll pigment concentrations in water bodies

605 Shipborne Acoustic Doppler Current Profile

1 Sholkovitz Gravity Corer

Resources

RRS Challenger CH121C

Cruise summary report

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