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Plans, leg 1

Overall plan leg 1The planned work consists of

1. Continuous acoustic mapping

  • Pelagic nekton
  • Zooplankton

2. Station sampling with:

  • trawls
  • plankton nets
  • acoustics/optics

3. Opportunistic sampling (by large midwater trawl and e.g. ROV)

4. Bird and cetacean studies.

  • Sighting, and if possible tagging.
  • Passive acoustics

5. Physical oceanography


6. Bathymetry mapping.

7. Deployment of long-term moorings and DOBO lander.

8. Conceptual ecosystem modelling.

Continuous acoustic mapping

General strategy: Combination of hydroacoustic mapping, depth-stratified sampling at fixed stations, and opportunistic sampling for identification of acoustic recordings in order to gain an overall grand assessment and description of the distribution and abundance of major macro-and megafauna species and communities associated with the MAR in the depth interval 0-3000m.

The G.O.Sars will follow a pre-set cruise track and sample with the available trawls, nets and acoustic devices on fixed pre-determined stations. Hydroacoustic data from five frequencies (18, 38, 120, 200 and 400 kHz) will be logged continuously. The information from sampling on the fixed stations, and multi-frequency analysis of the acoustic data will be used to distribute the biomass on species or group of species. Sampling resolution of the acoustic data will vary to some extent with frequency, but all data will be scrutinised and stored in cells of 1 n.mile horizontal distance and 10 m depth layers.

Station sampling

General strategy: To collect as much data as possible in support of the MAR-ECO component project PN1, Z1, Z4 and DN1.

We have designed two types of stations (long and short). On these stations we will perform a depth stratified sampling with trawls and plankton nets using opening and closing devices in the codend. (see Table 4 for details on equipment and sampling depths). The sampling will primarily support component projects PN1 and Z1. By-products will be samples for Z1, Z2, Z4 and e.g. ichthyoplankton samples for PN1 and DN4.

A UVP (Underwater Video Profiler) unit may be fitted on the CTD rosette. We also aim at mounting a bioluminescence recorder on the same unit together with a 150 kHz ADCP. At each station this depth-profiling device will be used from surface to bottom.

1. Opportunistic sampling
We base the continuous scrutiny of the acoustic information on the fixed station sampling. When the acoustic recordings change substantially between station additional sampling will be done to identify them. The ROV Aglantha will be available for deployment, e.g. when particular observations from the acoustics call for direct visual observations. Opportunistic sampling will also be done in connection with studies of marine mammal concentration.

2. Bird and cetacean observations
This will primarily be sightings but facilities will be available for taking biopsies of mammals and carry out satellite tagging. See project description for PN3 and above point.

3. Physical Oceanography
This includes collection of support data at all fixed stations, continuous surface sampling and adaptive studies when hitting frontal zones. CTD-casts and ADCP recordings will be made regularly in association with sampling activities with e.g. trawls and plankton gear.

4. Bathymetry
Multi-beam acoustic mapping is possible in exceptional cases, but may not be performed continously.

5. Ecosystem synthesis
A dedicated team, lead by the PI and a quantitative ecologist, will continuously synthesise and integrate information from various samplers and monitoring instruments into conceptual models of the ecosystem structure and processes.

Cruise journal

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

June 2004

July 2004

456  78910

August 2004


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