We have had rougher weather today than at any time during the previous week with winds up to Force 7, but work goes on around the clock regardless.
The early hours of the morning saw another attempt at a multifrequency acoustic survey using the EK60. Better results were obtained than the previous afternoon, simply because we were going in the opposite direction. Steaming tail to wind instead of head on makes a big difference to the volume of bubbles beneath the hull. The bubbles affect all the acoustic instruments, confusing the return signals. Reducing the bubbles allows a much better signal, and this time, a deep scattering layer was observed. We hope we can put nets into it sometime soon to find out exactly what animals the layer consists of.
By breakfast time we were back at the south east work site and the megacorer was put to good use, bringing back 5 out of 6 good quality cores. A thick layer of “fluff”, gungy-green phytodetrital material, capped each core and in some cases had been worked into the top layer of the sediment. There was plenty of evidence of bioactivity in the sandy sediment. The cores were rushed off to the cold room for closer inspection.
With breakfast over we set out to the mooring area to re-deploy the PAL Lander. This was done despite the deteriorating weather and increasing seas. Afterwards we headed south of west, back to the shallow (800m) seamount on the other side of the axial rift to recover the ISIT Lander deployed yesterday. Our course took us beam on to the sea, and for the first time we experienced a significant amount of movement. There were one or two crashes, but everything had been tied down well at the beginning of the cruise, so there were no problems, and it was fun having to walk up the deck that was sloping down only seconds previously. Fortunately we’ve got excellent quality “sticky” mats in the saloon to help keep our lunch in front of us while eating.
The ISIT lander was popped up late afternoon, to be followed immediately by a CTD cast. We were anxious that the CTD went without delay, because it was important to gather water in daylight for primary productivity experiments. The CTD had other ideas. Put in the water at about 6pm after a hasty dinner, it had descended to only 400 m when the alarm went off. The CTD was brought back on board and quickly discovered to have water in the cable termination. This was re-made while the scientist gathered in the conference room to review the situation and consider how to cram a further 10 days of work into four, with bad weather forecast for late Tuesday and Wednesday.
Since a window of good weather was forecast for Monday, the CTD was abandoned. It was too late for primary productivity work anyway and CTD’s can be done in bad weather. Good weather brings more urgent priorities and the ship is now heading back to the south east work site for an overnight trawl.
At least the catering department have ensured that our centres of gravity remain low. As well as the usual a la carte menu for lunch, there was green potage soup with fresh bread rolls, and a choice of all or any of curry, Cornish pasty, rice and chips – or salad if you prefer. Dinner included the traditional Sunday offering of steak, served with roast potatoes, peas and sweet corn. It could be preceded by cheese bruschetta and followed by pecan pie with cream – plus ice cream if you were man enough!
National Oceanography Centre, Southampton