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Plans, leg 2

Overall plan leg 21. Demersal nekton mapping and sampling
2. Epibenthos sampling
3. Zooplankton mapping and process studies.
4. Physical oceanography
5. Bathymetry
6. Retrieval of lander and moorings put deployed on Leg 1 (all except northernmost

1. Demersal nekton mapping and sampling.
General strategy: combination of hydroacoustic mapping, depth-stratified sampling using active and passive gears, and ROV observations, along cross-ridge transects in each MAR-ECO box. On Leg 1 of the cruise, semi-quantitative hydroacoustic mapping of demersal (benthopelagic) scatterers will be conducted along pre-determined cross-ridge corridors, spanning the depth range from the ridge crest to 3500 m on either side. Zig-zag cruise tracks will be surveyed using keel- and hull-mounted transducers (transmitting frequency 38 KHz). Data will be logged continuously. A sampling interval of 0.1 n.m. will be used routinely. Onboard regular
scrutinizing of the echosounder recordings will be carried out.

On Leg 2 depth-stratified sampling by the G.O. Sars will include bottom and semi-pelagic trawling using the standard Norwegian sampling trawl (Campeln 1800) with associated monitoring instruments, and still cameras. In each sub-area (MAR-ECO box) it is an aim to sample down the slope on either side of the ridge to 3500 m.

In the same areas as G.O. Sars is operating active gears and conducting hydroacoustic mapping, MS Loran will operate longlines and traps, in pre-determined depth-zones. The deep-sea ROV will provide direct observations and counts of demersal fish and cephalopods, and also epibenthos at selected locations, again depth-stratified. The ROV will also provide video footage and still photos.

2. Epibenthos sampling
Epibenthos sampling will include collection of still photographs, and sampling of benthic animals caught by demersal samplers such as bottom trawls. There will not be sufficient time to conduct dedicated sampling by benthic gears.

3. Zooplankton mapping and process studies
These are ROV and UVP based studies of behavioural and physiological processes of zooplankton, primarily gelatinous forms. By-products will be additional distributional information for Z1, and e.g. ichthyoplankton samples for PN1 and DN4.

4. Oceanography
This includes collection of support data in the focus areas, and selected special investigations in frontal zones. CTD-casts and ADCP recordings will be made regularly in association with sampling activities with e.g. trawls and plankton gear. Transect sampling to locate fronts may be accommodated.

5. Bathymetry
Multi-beam acoustic mapping of focus areas for demersal sampling may be made to assist the sampling activity, and to describe habitats for later analyses.

Cruise journal

Follow the G.O.Sars-cruise from day to day:

June 2004

July 2004

456  78910

August 2004


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