JC010: Mud volcanoes and submarine canyons


Cruise diary

Day 2: Friday 22 June 2007 - ship leaves port to start Leg 3
Position: 38°18.6N, 9°47.6W  (Google Earth reference 38 18’ 6"N 09 47'6"W)
Weather: Sunny all day

Tina writes:

"Yesterday was a day of celebration, today the hard work starts.  The first port of call is refuelling.  The RRS James Cook is very, very large and has very, very large fuel tanks.  Today we did not completely fill the fuel tanks and only took on 100 tonnes of fuel.  It took 3 hours.  Each tonne costs about £350 so the total cost of refuelling today was about £35,000.  Not cheap, I thought! Having said this though, if you were to have a car with a large enough (ie VERY LARGE!) fuel tank to store the same amount of fuel, it would cost around £99,000 to fill, as the fuel we use in our cars is much more expensive. When I spoke to Phil (2nd Officer) and Nick (3rd Officer), they explained that RRS James Cook is a very fuel-efficient ship, older ships can use double the amount of fuel.  Phil explained that by travelling at about 11 knots (11 nautical miles per hour) they keep the fuel consumption down, just by trying to go faster they can increase the cost of a journey by thousands of pound.  This is why the scientists work so hard to make every minute that the RRS James Cook is out at sea count. 

Today’s Itinerary:  Motor out to key location - Cascais Canyon (just off Lisbon) and deploy the Agassiz Trawl.

The Agassiz Trawl is a type of sieve that is dragged along the ocean floor 3,300m down.  The sediment is collected and this is then sieved separating the larger organisms from the silt on the ocean floor. Sometimes it is successful and the larger organisms come up clean, other times something blocks the sieve and vast amounts of mud from the seam floor is brought up needing to hand sieved on deck.  Very muddy! The Agassiz Trawl is being used because it may help answer a difficult question facing researcher Teresa Amaro.  Teresa is investigating what sea cucumbers eat as they are found in the deep sea where there is very little food. 

Sea cucumbers look like slugs but can be up to 40 cm long (see photo on the right).  Imagine treading on a 40cm long slug...yuck! However, apparently some species of sea cucumber are eaten! The sea cucumbers are found with their mouth part – the flatter end - buried into the sediment at on the sea floor and their rear end (the anus) pointing up.  Some scientists think they breathe through their anus, as this is the only bit that is out of the mud.  But this is something that someone will one day have to study.

These sea cucumbers have intestines like us so Teresa is able to dissect them to see what is in the intestines. She is trying to work out whether the bacteria she finds in the digestive system is helping the sea cucumber digest their food (like rabbits and cows) or if they are actually using the bacteria as food. Today the Agassiz Trawl is going down to find more sea cucumbers to study. Unfortunately, when it was brought up there were no sea cucumbers in it.


The night shift deploying the Aggissiz Trawl

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