JC010: Mud volcanoes and submarine canyons


Cruise diary

Day 5: Wednesday 16 May 2007
Position: Lat 35º, Long 6º, bearing 23.6º
Weather: Clear and sunny

Gillian writes:

"When I got up this morning there was no-one to be seen. Had pirates been on board? Fortunately not, but later on as people emerged I found out that the scientists had been working until 2.30am on the sediment that had come up from the seabed yesterday. Their aim is to find out how the mud volcanoes are powered. As soon as the sediment core was sawn open and the two halves exposed, plugs were quickly removed for methane analysis. Where is this gas coming from? Is it made by bacteria in the sediment or is it from deeper down below in the Earth's crust? Then larger samples of the mud were taken to squeeze the pore water out (the water in between the particles of sediment) and then tests will be carried out on this. This all has to be done in a special temperature-controlled lab with some special kit called a pore press. Doug and Belinda set up this very intricate piece of apparatus, all contained inside the kind of pressurised bubble you would expect to see in a hospital. It’s freezing in the lab; well not quite but you need your woolly hat on at 4ºC. Eduard and I could only manage 15 minutes! The scientists are looking for hydrogen sulphide, ammonia, chloride content and alkalinity. Some analysis is critical before it degrades so it needs to take place on the ship, but other tests can wait until they are back at NOCS. This will help build a picture of the flow of materials in the volcano and where they are coming from.

Sometimes things grind to a halt when circumstances beyond your control occur. In this case it was that the ROV had been brought up out of the water at 5am. It is obviously all happening when I am fast asleep! The problem was an oil leak. Unfortunately this delayed timings by 5 hours. But as Phil Weaver (chief scientist) explained when you are doing cutting edge research and using new techniques to push the boundaries of science sometimes it is inevitable that small hitches will occur. Isis was soon fixed and is now back in the water and surveying the ocean floor again.

The next exciting event is to witness the retrieval of the ROV and more cores at 8pm. More tomorrow..."

Doug working on samples in the 'bubble'

The pore press

Veit and Belinda tackle some core splitting...

...and then everyone helps out with core sampling

Eduard writes:

"Over the last few days we have been talking about the ROV Isis but we haven’t explained anything about it. What exactly is the Isis? And what is it for? 

Isis is a submersible vehicle, a submarine that can operate underwater to explore the oceans. ROV means Remotely Operated Vehicle, so it can be controlled from the ship. There is a cabin besides the Deck Lab, plenty of computers, screens and a sort of command module (See photo below and also more details on our special Isis feature).

Isis is going to dive several times during this three-week expedition, to study the seafloor of the Gulf of Cadiz and its Mud Volcanoes. All the crew are very proud of Isis. Everybody talks about Isis as the jewel of the ship. It should be, because it cost about 4.5milion £ (about 7milion €). I don't think I could afford one! 

When I was in Barcelona, I saw photos of it. It looked so small to me. The real impression was the first day I arrived on the ship. It is really impressive. Its design is similar to another American ROV, Jason - which was used to film the wreck of the Titanic.  Isis has two mechanical arms - I was really surprised when I realized that one of the commands in the command module is a little reproduction of these arms.

Yesterday evening, Isis dived for its first bathymetry survey (see photos below). As you can see, Gill is becoming a brilliant photographer! Phil, Gill and I, while we were watching Isis going down, had the opportunity to see a magnificent sunset!

The scientists are excited because they can use the ROV for a sort of experiments and measures: aqua monitoring, photomosaicking, video transects, colonisation rings, bio box, suction sampler, micro bathymetry, video camera …!!! After seeing Isis disappear under the sea, we went to the command module. While Isis was going deeper and deeper, I could see on the screens what the Isis was recording: shrimps, squids and a sort of little fishes were swimming around! 40m above the seafloor, Isis started collecting the first bathymetry data (information that tells us about the 3D shape of the seafloor). Unfortunately, about 05:00 this morning Isis developed an electrical problem and the technicians had to bring it it back on board to fix it. But by lunchtime Isis was all fixed and ready to get back to work..."

Isis takes the plunge in the depths of the Gulf of Cadiz...

...whilst the ROV team watch carefully in the control cabin

Swift repairs meant that ISis was back in the water within a few hours

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