CD179: Deep-sea biology of the Portguese canyons


 


Daily diary

Monday 8 May 2006


Xana writes:

"It is midnight and the Agassiz Trawl just landed on the bottom at 4500m (3 miles deep). The “boss” dragged it for 45 minutes before hauling it back. It is the middle of the night, the boss and Jerry are seen through safe reflective clothing pulling the net back in

There is great anticipation to see the long-awaited catch, but the cod end was empty, probably because of too much sediment or catch concentrated on the net, forcing the rope at the end to brake and opening, loosing all its contents while hauling. What a disappointment!

Straight after the Agassiz Trawl, we deployed the Megacorer. We got 3/3 Multi and 8/9 megacores in total. One multicore was sliced in 1 cm intervals down to 10 cm for foraminiferal faunal work, one was sliced in 1 cm intervals to 5 cm and the in 5 cm intervals to 15 cm for metazoan meiofaunal work, and the third multicore was frozen for organic carbon analysis. All 8 megacores were sliced in 0-1, 1-3, 3-5, 5-10 cm intervals for metazoan macrofaunal work.

During my resting period 8 am to 8 pm, the day shifters retrieved the Amphipod trap deployed on the 7th May, did one Megacore deployment at 4300 m in the Nazaré Canyon, and the second Megacore deployment arrived at 20:30, just in time for the night shifter to get back into action.

We manage to do 2 more deployments during the night both at 3500 m. Most megacores were retrieved empty or did not fire. The few we did obtain were useful for holothurian feeding (trophic) studies for Teresa. She was thrilled with her Molpadia burrowing sea cucumber and surrounding sediments. The aim is to analyse the gut bacteria and also the sediment bacteria and assess their role in the nutrition of the holothurian.

And another 24 hours have gone..."

Terry and Dave in refelctive safety gear

Empty catch - what a disappointment!

Megacores



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© Challenger Division for Seafloor Processes
April 2006
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