Hello all, I'm afraid this is going to be a short post today as I am completely knackered after a long day of actually doing stuff!
It doesn't sound like much, but today I helped with 2 piston cores and 1 ROV transect.
OK, quick translation here: a piston core, as far as I can gather is a long metal barrel with a piece of plastic drainpiping inside (long is 9m in this instance) this is lowered on a cable with a piston mechanism at the top of the tube with a trigger lever set in the off position by a second short dangling metal barrel which reaches the seafloor first, releases the leaver which triggers the piston which essentially drops the 9m barrell with force into the sediment. The result is that you pull out the plastic drainpiping (once back on board) and chop it into managable sections all filled with sediment (here gooey clay mud), which are then sealed on the ends then split down the middle so that you get a manageable cross section of what the sediment layers look like 1000m under the sea. We were looking for patterns of "holocene sandy cordite"- again I needed translation here- the geologists wanted to know about the speed and positionin of the deposit of sand around this bay-like deep spot, which is affected by 2 different watermasses who changed their sedimenting pattern in the holocene era. They were curious as it looked like it graded really fast over a very small area, from previous cores, so they wanted to see whether this was actually the case. (phew!)
After 2 of those, getting very muddy, and very wet thanks to the rains from greenland deciding only to fall the 2 times we had to be on deck playing with mud (- that was cold!), I was then charged with the digital logging of the ROV transect. This was essentially a camera being sent for a drive over the Darwin Mounds to see if there is any coral left on them. The mounds are 1-5m tall and 60m across and really just look like pimples on the seafloor. This is mostly interesting to the geologists as they are debating as to how they were formed, but we also want to know about the corals that live on these mounds. They were discovered 10 years ago by some of the people who are on this boat, and as they had coral on them there was a big rush to protect them as interesting features. However as the protection proceedure took a while to come into place and had hit the news at the time, a month before closing to bottom trawling the fishermen came in and ransacked the place, knowing only that it is a reasonable fishing ground that they soon cannot access. So our secondary purpose is to see if there is anything left here of the corals and of the mounds. And if they have been ransacked by trawlers, after 10years of closure is there any regrowth, if so where are the young corals coming from. The ROV can show us pictures of what it looks like down there, and it also has a manipluating robot arm that can be used to pick up samples (I'll show you some pictures of the fancy plastic sample box contraption tomorrow).
The result was that we saw mostly sand with these interesting creatures called xenophyophores all over it (xenophyophores are giant protozoa - massive single celled organisms that are 10cms across and just look like footballs of sand lying on a flat sandy surface), which was expected on the tails of the mounds (the sediment build up behind each mound relative to the current), while on the mounds (we only looked at 2 right next to each other) there was lots of dead coral rubble, clearly having been trawled, interspersed with other organisms that can find hiding space amongst the debris (sea stars, brittle stars, urchins, soft corals and sponges mostly) but on the whole it looks pretty desolate. The plan is to go and look at another couple tomorrow and see if there is any coral left living. We saw only about 3 living specimens during todays 4 hour transect!
The interesting thing here, particularly for the JNCC representatives here (the government agency responsible for creating the protected conservation areas outside of the 12mile inshore limit in Britain) is whether this area is still worth protecting. And if not, how does one unprotect a protected area?!
So essentially my job during the ROV dive was to write notes to the effect of "ROV deployed" "ROV on the bottom" "sample 1 being taken" "coral rubble visibile, no live specimens" and "octopus!", which I find strangely fun, purely because I know what's going on, and if there is anything interesting to see, like the octopus, I get to see it :).
Ok, that was my "short" post for the day. Soon I shall actually give you a run down of why I am here, but first I must sleep as I might have mentioned, I am ZONKED!
Good night all.
The last few positions and the next few positions will all be up here in the darwin mounds area- essentially the most north easterly corner of the rockall trough in bay made by the Wyville-Thompson bank.
An idea of what a multibeam map looks like red is shallow down through yellow and green to blues which are deep. This shows you what the mounds look like rising slightly above the seafloor, the two pronounced coffee bean shaped mounds on the left are the ones we went over with the ROV.
Not a great picture, taken on my mobile phone. This is Becky and Tim looking at the split piston cores. As you can see, yes there is mud at the bottom of the sea!