14 July 2002 - End of the Cruise
RRS James Clark Ross Diary
Position at 1200: 59° 25.1'S, 007° 39.0'W (About 70 miles north west of the Isle of Lewis, Outer Hebrides)
Distance steamed since Grimsby (10/09/01): 54440 Nautical Miles
Air temperature: 12.7°C; Sea temperature: 12.7°C
JR 75 Ends and 76 begins.....
Another week over and we have said good-bye to our colleagues of the last few weeks and are presently steaming lines off the Outer Hebrides conducting a geophysical survey on behalf of the British Geological Survey. It is essentially a seismic survey which requires a lot less people than the previous cruise, so you could say it's awfully quiet onboard now. We shall go into the present science next week when hopefully we'll have some pictures to show you.
So for the last week; Monday morning bright and early saw us recovering the photolander of which there is more in the science section below. Then it was off to Stornoway on the Isle of Lewis. That's in the Outer Hebrides for anyone whose Scottish geography is as challenged as mine (i.e. top left). We arrived late on Wednesday evening after completing our last piece of science, which was a seabed mapping survey around some mud volcanoes that are just to the north west of the Shetland Islands. Our arrival in Stornoway was timed to perfection, as always, as the pubs were just shutting. Thursday treated us to a fine and sunny day, this was after a couple of early showers which did not bode well for demobilisation and mobilisation. I think we all had images of the downpour we had mobilised in four weeks earlier in Leith. The pictures below show a little of Stornoway from the ship; the left hand one shows the main town area, while the right hand one shows Lews Castle in it's slightly elevated position surrounded by most of the islands trees, so I am led to understand.
The work progressed well thanks to some advanced planning and saw us saying goodbye to the JR 75 science party. They were mostly from Scottish Association for Marine Science (SAMS), with groups also from University of East Anglia, North Highland College, the Scottish Universities Environmental Research Centre and the Scott Polar Research Institute. It was an unusual departure for us to watch. Having loaded the heavy kit onto their trucks they picked up their bags and walked around the harbour to the passenger ferry terminal for the mainland, from one boat to another. Don't worry we weren't making them walk home, they had a coach waiting for them at the ferry terminal at Ullapool.
Above: Left - the group photo for JR75. Right - the group from JR75 departing on the ferry 'Isle of Lewis'. Click on the images to enlarge them.
The Science bit in the middle
Recovering the SAMS photolander by Murray Roberts
At 1 o'clock in the morning exactly 20 days after we positioned the photo lander by the Sula Ridge cold-water coral reef complex, the James Clark Ross slows as she comes back into position above the lander. Once the ship has come to a stop we lower a small transducer over the side. After paying out enough cable to take it clear of the ship's hull we use this transducer to send sound signals to the lander. First we check to see the frame is still vertical - sighs of relief when it replies that it is. Next a signal is sent and echoed back allowing us to see how far away the lander is. The ship is in a good position about 300 m to the side of the lander and at 1.13 am we send the command to release the ballast weights that have been anchoring the lander the seabed for the last three weeks. Everyone crosses their fingers as we again check our distance from the lander. If it releases successfully this distance or range should start to drop away as the lander rises through the water. Our first range was 609 m, our second 607, then 606, 603 - the lander's on its way back.
We quickly haul up the transducer and make our way to the bow of the ship to try and see the yellow float when it hits the surface. After our time in the Arctic Circle there's quite a crowd enjoying the first sunrise in almost three weeks and over the stern the sky is turning blazing red and orange. Luckily for us, for the five or so minutes it takes for the lander to travel up through 280 m of water all eyes are facing away from the spectacular sunrise as everyone tries to be the first to spot the lander. Five minutes go by and we're starting to feel a little anxious - shouldn't it have appeared by now? Another minute drags past and then there's a shout of 'Thar she blows' from the bridge, Colin has spotted the yellow float off the starboard side and about 300 m ahead of the ship. As the sun rises, the JCR carefully manoeuvres alongside the float and a grappling hook is thrown out to catch it. The crew pull the float back to the stern where it is lifted onto the deck. Just 35 minutes after releasing the lander from the seabed, it is safely tied down to the deck. A round of applause ripples round the sun-worshippers on the upper decks of the ship.
Now's the time to check the lander - any signs of damage, are the cameras and instruments still running, how much information has it gathered over the last three weeks? At 2 am we see the optical instruments fire up and shortly afterwards one of the cameras takes a picture - very promising. We remove the computer from the digital camera, extract the tiny hard disc and check to see if it's worked. There are over 400 images stored on the disc. We open a few to check. The images show several boulders, dropped 8000 years ago by passing icebergs. They are covered in colourful sponges and below we can see they are also home to bright orange squat lobsters. As we look at other images we see lurid green threads appearing and disappearing on the seabed. These are the long tongue-like feeding structures of giant worms. These so-called echiurans scour the seabed with their tongues for fresh food material to pull back into their burrows and digest. By doing this they rapidly bury this fresh material in the seabed and are likely to be very important agents in the process of mixing materials into the mud and sand of the seabed by the Sula Ridge. It's been a long night but as 7.30 am and breakfast approaches there's a huge sense of relief that the lander returned on cue and has recorded a three week glimpse into the hidden world of the Sula Ridge.
Doctor of the Week
This week, also, saw the departure of our Doctor of the last season, Sarah Hortop. She seems to have gained the title of the longest serving Doctor onboard JCR having joined at the beginning of September and so has completed just over ten months straight. We see Sarah in the picture below back in the down south days a few months ago. We wish Sarah all the very best for the future and thank her for everything she has done whilst onboard.
This week thanks go to Jeremy Robst and Pat Cooper for allowing me to use their images.