CD179: Deep-sea biology of the Portguese canyons


Daily diary

Thursday 4 May 2006

Abi writes:

"Over the past 24 hours, we have processed two megacores from them the about 4400m at the mouth of Sétubal canyon, the first of which produced quite short cores as a result of the sediment being very stiff at about 10cm depth, preventing further penetration into the mud. 

The second challenge of the day was carrying out a piston core at the same depth and location.  This was unfortunately not successful; the core most likely hit a hard, gravely bed, which caused the core catcher to break off and the inner tube to be lost.  When the corer was recovered we saw that the nails holding the core catcher to the main corer had been sheared vertically in half by the force with which it hit the sea bed!

Next came the deployment of SHRIMP.  We decided to do a SHRIMP run over an area of open slope at 2800m adjacent to the Sétubal canyon, so that I would have a reference site with which to compare all the video data I have gathered from canyon sites.  Sadly it was not to be as a problem with the fibre optic cable meant that SHRIMP had to be hauled in from 1000m.  The SHRIMP technicians worked through the night, streaming out the cable behind the ship to find the kink in the cable and straighten it out; the kink was 5000m up the wire!  We’re now planning on getting this reference site to the north of the Nazaré canyon instead. .."


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April 2006
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