CD179: Deep-sea biology of the Portguese canyons


 


Daily diary

Friday 28 April 2006


John writes:

"With the weather considerably improving the 24-hour rota of the deployment of scientific instruments is gathering pace. As a result, the already close integrationbetween the Night and Day watches is becoming ever more seamless. Yesterday saw both ''watches'' on the bridge looking for the multiple yellow balls of the 'flotation collar' of the Amphipod Trap, as described so well in Abi's diary yesterday. This early morning picture shows Abi ,Dario and Veerle  on the bridge all looking for the  'trap'.

All hands on deck to look for the yellow floats of the amphipod trap

Today for us started with the recovery of the Agassiz Trawl. This had been lowered by the night watch 3200 metres into the Cascais Canyon. The trawl itself consists of a large conical net closed at its narrow end by a tie and attached at the front to heavy metal frame, which acts as a huge mouth holding the net open. The picture below shows the net end being opened.

Landing the trawl on deck...

...and getting it open

Above shows the Trawl being landed on deck. Unfortunately the net has come off the left side of the frame resulting in a very small catch. Quality counts however and our first three burrowing Sea-Cucumbers were found, proving their presence in the Cascais Canyon for the first time. These sea-cucumbers (called molpadiid holothurians for the initiated) live buried in the sediment head down. They stay connected to the sediment surface by their short tail (seen at the bottom in the photograph below). They have ''respiratory trees'' attached to the tail through which they pump water to ''breathe''. These holothurians appear to be specialists in muds that are regularly on the move, such as in the bottom of a canyon. Life on the canyon floor has its advantages because there is more organic matter (food) there,but it is also regularly flushed by strong currents that resuspend the sediments. This means that the animals that can stay buried have an advantage over those that live on the sediment surface.

This particular aspect of the day was a highlight for Teresa who went straight into her dissection work investigating the function of bacteria in the sea-cucumber gut. Picture 5 shows Teresa measuring her first sea-cumber in the cold lab. (4ºC!)

Holothurians...

...being dissected by Teresa!

Following the trawl we then steamed to the Setubal Canyon for two more Piston Core Biopsies of the canyon floor. These were preceded by the weekly 'boat stations' drill followed by the 'B' Movie: 'Safety at Sea' in which some well known local actors were recognised. The piston-core technique and method were as presented in Sarah's diary on Wednesday. These were both successful and Raquel was pretty pleased with most of her samples.

I think at this stage we really must mention the consummate professionalism with which all the scientific support staff go about setting up and deploying these often highly complex and frequently huge and heavy  deep- sea vehicles. This is an amazing team with unique experience not to mention their sense of humour!  Be it Jez and Rhys on the Piston Core, or Ian and Lee on Shrimp and Tobi, or Terry with the CTD/Saps, it all looks so smooth and easy!

Passing through the 'wet Lab' I happened to notice Terry's tool kit. It strongly resembles that from an orthopaedic operating theatre, and then I saw Terry checking his patient!!! Improvisation is also the name of the game as the picture of Terry and the PSO shows. It takes years of experience with a broom to perform this manoeuvre. There is also the enormous amount of preparation work that goes on before each trip followed by the huge logistical programme of getting everything on the ship and started. The night shift, controlled at times with difficulty belongs to Ben and to see what he sometimes has to deal with look at the picture below . This shows a member of the night watch who at one stage, I think, has had an 'overdose' of mud from the Megacore. When last heard of she was making good progress...."

Quietly in the computer room is Martin. Not only is he in full control of all our communications including the email system but also he is also editor-in-chief web pages, in-house diary, news summaries etc. as well as having to put up with all of my ignorance on my Apple! As newcomers to scientific cruises I think that both Sarah and I now know what the "Cruising Terms" such as 'Box-core. Piston-core, Shrimp. Tobi CTD and SAPS  all mean and as importantly their implications in terms of planning and workload for all concerned.

The sunsets are getting better daily but none of us has yet seen the famous ''green flash'' as the sun finally sets on a cloudless horizon at sea. Perhaps next time!"

 

The team working on the piston core

The on-deck first aid kit - ready to treat any equipment malfunction!

Keeping the kit in good working order

Abi has a mad moment

Another great sunset to finish the day!



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© Challenger Division for Seafloor Processes
April 2006
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