If you want to do on-board experiments on a specific specifies there is one proofed method to get them: Target fishing. Oh the jollies an excitement of target fishing.
Firstly the method takes advantage of the acoustics on-board the ship. To put is in the most simple of terms a sound (acoustic signal) that is sent straight down the water-column will hit object in the water-column and part of this signal will return to the ship. This idea is similar to that of radar that the ship uses to detect iceberg and other objects around us. But instead of making a sweeping movement round the ship the acoustic signal remains directed downward and follows the movement of the ship.
With these acoustic signals three different wavelengths are used. This allows discriminating between various types of objects. Anyhow that the scientific part of it. At the beginning of a target fishing period the RMT 8 has been put on the deck at the beginning of the target fishing both nets cocked (like a gun) and ready to go.
When a mark indicating a swarm of krill, is spotted (see the red blob in the picture) the bridge is phoned and a marker is put at the time when the swarm is detected. This allows the ship to find this spot again on the cruise track of the ship. Then the fun starts. A “battleship” turn is initiated. This is basically a turn for emergency situations, such as an iceberg in front of the ship or a man overboard. The direction of this turn is specific for each ship, or rather the rotational direction of the propellers. When turning to one side the prop will actually help in making the turn, turning to the other side only the rudder will give the force needed for turning. After these manoeuvrings the ship will return in its own tracks.
This is the time for action: we need to get on our weather gear, our safety boots, work helmet and safety harness. Some at such times feel like firemen swept up b the alarm, other like fighter pilots getting ready for a scramble, the more down to earth ones among us…. Just like fishermen… Then the net is put over board and lowered to the depth were the swarm has been seen before. When it then comes back on the screen the net is guided through the swarm opening right in front of it and closing just behind it. Then the net is brought back in with a catch that hopefully allows people to do some work.
In the Southern part the catches of krill Euphasia superba were quite large however by the end of this transect other species have started to take over E. triacanta, E. valentini and Thysanoessa sp..
Oh no, more than a week since my last post…… Well things have been busy around here. I’ll put in extra pics to compensate. Putting in the nets, sorting out the catches and when there is time trying to get some exercise or work on that paper that needs revision.
The JCR has a tiny gym, never the less it is well equipped. But each time I get in there I wonder how they managed to fit everything in there: Was it all measured out in advance or was it a case of trail and error (or bump?). Additionally there’s also an extra workout at 16.30 on Mondays, Wednesdays and Fridays: Circuits. This takes place in the fore hold and is lead by the ships doctor Nerys (This is a welsh name with no etymological link with Nereis diversicolour). Basically it’s about seven stations where you have to do a set of exercises (for instance ten press ups, ten sit ups and ten military star jumps).
First time round you have to repeat these exercises for 3 minutes, the next round 2 and finally 1 minute. There is a small group of hardcore participants (Picture: Ruth, me, Garaint, José, Alex and Nerys) and the occasional influx of other people depending on their work. Anyhow it is all great fun and a great way to start the day unless of course you get called out to start working on the nets…..
Traveling across any part of the Southern Ocean gives you the chance to see unique seascapes, magically sculpted icebergs and a unique wildlife. These things might sometimes make you forget what a harsh environment this is. Here the struggle for life and survival of the fittest can be equally harsh. In the last few days we’ve seen a perfect example of what survival of the fittest means and how relative this is. There is a small white heron called the Cattle Egret. This species is originally native to parts of Asia, Africa and Europe. It is found most in dry grassy habitats often accompanying large mammals such as cattle or even rhinoceroses and feeds on invertebrates and small vertebrates.
With the expansion of man this species has undergone a rapid expansion and successfully colonized much of the rest of the world. So in a global context this species is really successful and can be considered being quite “fit”. However this is quite relative and we’re seeing the brute example. Yes a long bill and a hunched posture is great for picking at those insect and little vertebrates hiding in the grass. Those long stalky legs are also perfect for walking through small shrubs. And that dispersive nature is great for getting you around and to find new pastures, but what if you end up in the Southern Ocean. Well then all of this gets you nowhere. Without salt glands drinking seawater is out of the question, so there’s no drink around for miles. Without waterproof plumage resting on the sea is a dangerous endeavour, especially without webbed feet to help paddling around.
With luck it is possible to eat some invertebrates but that’s hard to do without getting more saltwater into your body. So the only thing left is trying to rest upon a research vessel passing by, trying to get those feathers dry and to survive another day. The first day we saw the Egrets they were about 22 a day later their numbers were already greatly reduced, by now they are gone..
One knows sampling has properly started when the most you get to see is either the inside of your eyelids or the contents of a sampling bucket. As we seem to be arriving at a new station almost every day our days are packed. Our schedule should be one long night every three nights but so far we’ve had three long nights in a row. This is actually the first night that is a tad bit more relaxed and allows me to write another contribution to the blog.
Usually a sampling night starts with some target fishing for krill. For this the RMT 8 is used to sample specific location were the acoustics have indicated the presence of krill. However it has proven astronomically difficult to find krill patches and to successively sample them in large enough numbers for the different studies that are going on. So we often use al if not more than our dedicate time in order to find these ever elusive krill. To make things more fun salps seem to be quite abundant. (Some scientists will say this is only logical but we’re not going to discuss the contents of Nature papers here). Salps are jelly like things, often referred to as the vacuum cleaners of the oceans. For us however they are quite annoying, and beyond the fact that they protect the catch from being damaged by the net there is few positive things to be said. They weigh quite a lot and seem to be blocking anything. Furthermore as the whole catch needs to be processed we need to go through them as well. As soon as everybody is happy with the amount of krill that have been caught, we can move on to other things. This can either be an array of sampling devices with exotic names as the GoFlo, the FRRF, the HPLR, the bongo, the other bongo, the MOCNESS and CTD’s (you cant do oceanography without deploying plenty of CTD’s). Generally these devices require little help from our behalf. So when these are scheduled it’s a slow night for us and we can occupy ourselves with other things. But as told we haven’t had many of those yet. It’s when we deploy the RMT 25 that things get serious.
The RMT 25 is probably the larges net on board and like the RMT 8 is composed of two rectangular net that can be opened and closed from the ship. During a night we deploy it twice. First to sample the upper water masses (400 to 200 and 200 to surface) followed by the deeper water masses (1000 to 700 and 700 to 400). The reason for doing it in this order is twofold: first it allows us the most time to sort out the first catch and as these deployments often get delayed, it is better to sample the deeper layers closer to dawn as the behavior of animals will be less affected by the increase in sunlight. As we are all quite keen on fish and other creatures from the depths of the Southern Ocean it seems we al get an extra jolt of energy once the catch is on deck. Because of the large amount of salps this can be a quite difficult job. The first step in the main lab is sorting out all the fish and invertebrates from the salps. Once this first step is done Gabi generally takes control in writing down the different species and quantities. Usually Yves dives into the invertebrates, identifying a wide range of specimen at sight. Meanwhile José and I attack the fish, we sort them by species and when in doubt Yves has a look at the otoliths often to confirm our suspicions. After that it’s measuring time for José and writing time for me. By the time we work ourselves through all of the catches it is often getting light or it is well beyond that point. So while other people are getting up for their shift and a breakfast we get ready for some good shuteye.
Anyhow working the late shift often gives unique experiences. When we were bringing back the LHPR, a group op chinstrap penguins was feeding next to and behind the ship. From the deck we could see their little bodies darting through the water and occasionally jumping out. Anyhow time to go to bed, before we get blinded by the morninglight……
As we were just of the shelf of the South Orkneys we had quite a mass of water below the ship, over 5000 m of depth to be sorts of exactly. As the first night at this station didn’t involve deploying the RMT 25 we only had to help deploying the other gear. Just at the end of our shift a deep CTD would be deployed.
So it was time for a physics experiment. The duty mess was raided in search of polystyrene cups, the disposable cups you get hot beverages in. These cups were den clearly labeled and put into a bag. This bag was then attached to the CTD to make the trip below 5000 m. The results of the experiment were astounding.
As the depth increases by ten meters the pressure increases by one bar. This means that at about 5000 meters you have a pressure of 501 bar. While such an increase in pressure doesn’t affect solid materials (The CTD looked pretty much the same coming up) it does affect more compressible materials such as polystyrene cups. Anyhow, the before and after pictures should speak for themselves.
On this campaign there are four people working on fish: José, Gabi, Yves and me. We form quite a heterogeneous group in terms of nationalities and interests. José is a highly energetic Portuguese squid and top predator specialist. Gabi is a German scientist working at BAS that analyzes the foodweb structure of the Scotia Sea using isotopes and fatty acids. Yves is a French household name in the study of penguins and other predators. This group is completed by a Belgian guy doing ecology and genetics.
Our main task on board are helping putting the RMT 25 nets out as well as sorting out the catch an preserving everything so it can go back to Cambridge. Their the samples will be set to use for various purposes to suit our needs. As most of the fishing with the RMT 25 will take place during nighttime, when it is easier to catch the fishes, we’re all on a night shift (18.00 to 6.00 Falkland time). So last night we finally got the chance to get started with the proper work. And getting the Big RMT 25 in and out of the water is indeed a proper job. It takes at least four persons to haul in the nets, especially if they are well filled. And after that it’s sorting time: looking at the various specimen net only fish but also jellies, decapods and amphipods. Once in a while an exclamation is heard in the lab when a new curious specimen is discovered. All in all the first catch wasn’t that big, but there was a considerable variety and it was just he right size to keep us occupied until the end of our shift an curious for more discoveries.
The last couple of days we have been slowly getting into action. First we did a test station were all of the gear was put into the water. This allowed testing both the equipment and the people handling them. Most of the gear seemed to be working well until we started testing the RMT’s. First was the RMT 25 which is supposed to catch fish. This net is composed out of two net that can be opened remotely. Although, that’s how it should be… When we tested the release mechanism nothing happened. Then it was decided to test the RMT 8 which is more suited for catching krill. Initially this release mechanism failed as well… But soon we found out that it was a technical miscommunication and we got it working. So hopes went up for the RMT 25 but the second test was also unsuccessful. So it was back to the workshop were peter would have a look at it.
Anyhow by the next day everything got sorted out. Apparently it was a tripped display of Murphy’s law: pushing the wrong button, clogged gears and bad electrical wiring. So we were finally able to sort out our first catch which was dominated by salps. By the afternoon today we arrived at our fist official station and we are now changing to night shifts as this is the best time to catch fish. Although the first CTD’s were deployed successfully weather has been picking up making further sampling quite difficult. So hopefully it will slow down by tomorrow night so that we can get our first proper tow in.
It may be our first day out as sea, but foremost it is meeting day. The first meeting was at 9.00 with the krill team in order to get everybody up and running: Who needs what amount of krill and in what condition (apparently there are lively, near dead, recently deceased and decomposed). After this meeting it was time for the second emergency drill. We all had to go up to the muster station with warm clothing, survival gear and a life jacket. Luckily we didn’t have to put on all of it (especially the flotation suit, which is not only a hassle to put on but also and instant steam bath). Dressed with our life jacket we had to go into the cozy survival boats.
Thanks to the good weather everybody managed to get in and keep their food in as well. After the muster it was time for the fish people to come together to explain how the RMT’s work, especially the 25. In any case I am looking forward to pulling this huge net out the water, it will be a great difference in comparison to the RMT 8 that was used on my previous campaigns. After lunch came an isotopes meeting, which wasn’t mandatory for me but it was quite interesting nevertheless. The final meeting of the day was less mind-bogging: An hour in the gym together with José. We both hope to motivate each other to keep on doing daily exercises on the ship. We’ll have to see what happens in that regard. Tomorrow we will arrive at the test station. Here all of the equipment will be tested for use and give new people on board some time to get used to them. More later…
If we had good weather the first day it changed soon. The wind picked up considerably and we were struck by the occasional shower. At last weather that one would expect at the Falklands. Yesterday was al about unpacking gear and lab equipment, or not entirely. Sophie, Peter, David and Min crew who arrived early did such a good job bringing all the big stuff in order that there wasn’t much heavy work left to do. So after venturing onto a fruitless quest around the ship searching for people in need of help, I decided make the best of doing some computer work and tidying in our cabin. Because of all the good work and slowly improving weather we could actually manage to depart earlier than scheduled.
This morning we all received the news that shore leave would end at 16.00 and that we would depart at 17.00 (all in local time). As the ship inched away from the dock the scientist made their way to the top of the ship, the monkey island. Sailing out of the bay we said our goodbyes to Stanley and the Falklands. Not sooner did we leave the shelter bay of Stanley or we would be greeted by the first wildlife. Around the ship little puffs would appear, a tell tale sing of whales, in this case most likely Sei whales. Although it was hard to tell as they never came close enough to identify them with absolute certainty. As we started upon the open water one jut came close enough for a positive identification. Sei whale after all! In the evening there was a short get together for a birthday. Nevertheless everybody went to bed quite early, to be gently rocked asleep by the ship.
After a series of circumventions with time spent in various vehicles the Falklands have finally been reached: Trains (3,5 hours) buses (3 hours) airplanes (18 hours). Since we just arrived we just have to do personal stuff: getting our stuff to our cabins and getting everything stowed away. However there were more urgent matters at hand: going for a walk. The weather upon arrival was just great 20°C and no wind. After being stuck inside it was great to have the chance to get out and stretch out legs. Soon we were a group of seven, Gabi, Hugh, José, Sebastian, Daria, Ruth and I.
The first destination was Gypsy Cove. On the way we passed one of the postcard marks of the Falklands: an old ship hat ran aground in the same bay were the JCR is docked. This is a beautiful area with large colony of Magellan penguins. These little guys actually live on beach were supposedly there still could be landmines left from the Falkland conflict. As a positive side effect this provides these penguins with a perfect sanctuary: nobody would ever dare to walk out on their beach. Anyhow I’ll let the picture speak for them selves.