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19th June 2007
It is interesting to watch how everybody has his own way of securing their equipment depending on what is available and on their previous cruise experiences. It may sound difficult to believe, but at the moments like this, simple materials like rope, nails and scotch are worth their weight in gold. After all, the nearest hardware shop is not exactly around the corner. Just before sailing, one last but equally important task is a quick trip to the local shop for vital provisions - sweets, newspapers, puzzles, etc. for the next few days out at sea. Dinner gathers everyone together between 6-7pm, and offers a last chance to go through the checklist before the Celtic Explorer cuts the lines and sails out of Galway towards its destination: the Porcupine Abyssal Plain site, or otherwise known just as PAP. As the ships pulls away, most of us are on deck waving good bye to the lovely Irish town and to solid ground. We are all excited and happy to able to take part in this cruise, wishing for good weather so that we can complete our mission successfully. 20th June 2007
The weather is rather good. Although it is cloudy we even have some sunshine now and then breaking through the cloud cover and the sea is relatively calm. So the program continues as planned: instruments are being assembled and the mooring is being prepared by the engineers to be ready when we arrive at the PAP site. What was on the menu today onboard the CELTIC EXPLORER? 21st June 2007, 19.00 GMT
Around the Porcupine Abyssal Plain site, and in the North Atlantic, vast phytoplankton blooms occur in the spring and early summer in the surface waters which satellites can easily photograph from orbit. Satellite sensors are invaluable in reconstructing global maps of ocean productivity, but they have a limitation: they cannot penetrate deeper than the surface few meters. Our mission is to monitor throughout the year, the changes in phytoplankton below the reach of satellite sensors using instruments attached to a seabed attached mooring. We have been doing this since 1989 at the Porcupine Abyssal Plain site and the data helps us determine the variability in seasonal as well long term changes in phytoplankton production and particle flux to the deep sea.
Before we attach the fluorometer to the mooring line and deploy it for a full 12 months, however, we need to test it. For that the fluorometer is attached to the frame of the CTD (Conductivity Temperature Depth) Rosette – the workhorse of modern oceanography, and then plunged into the water down to a depth of 300m. This is a pressure tests as well as a check to see that the sensor logs data as it should. In addition we also took water samples from the CTD Rosette bottles at various depths in order to calibrate the fluorometer sensor once back in the lab in Southampton. So, once the tests are successful, all that’s left to do is re-programme the fluorometer so that it measures the chlorophyll concentration every 2 hours for the next year and then we are all set! What was on the menu today onboard the CELTIC EXPLORER? 22nd June 2007, 0.15 GMT
One of the CTD Rosette deployments today had my sensors attached to it. This allows us to calibrate them, that is having a profile of the water with the sensors whilst being able to take water samples to check that the sensors are giving us the correct reading. That done, they are ready to be deployed for 12 months on the long term mooring. I have been changing the programming on the sensors today so they are now ready to be fitted to the frame and put overboard later on today to give us the nitrate concentrations at the PAP site every 2 hours for a whole year. This data, along with the data from the other instruments on the frame, will allow us to follow what is happening at this part of the North Atlantic at several depths and throughout the next year. 22nd June 2007, 19.15 GMT
It was a good day! And not just because of the weather, but because we fulfilled the major part of our mission and deployed the new observatory at the PAP site. While our cooks were preparing a delicious omelette for lunch, on deck the last preparations for the mooring were performed. After complementing the instrument frame with all the required instruments and all the last checks, we started with the deployment at 14.15 GMT. It was very exciting!
It took a while to complete the deployment. The last to go was the anchor – a weight of 3 000 kg to keep the mooring from floating away with currents. Over 4 hours after we started, we watched the anchor slipping into the water and beginning of its way down to 4,800 meters at  49° 00 North and 16° 24 West. At 18.15 GMT, the brand new PAP1 ocean observatory was successfully deployed! Thanks to all involved for completing the mission! 23nd June 2007, 20.20 GMT
However, the pleasure of taking part in this marine cruise is enough to make me forget two days of seasickness. Discovering the life and research activity aboard the Irish ocean-going vessel, as well as the sea life in the open ocean, is a great experience. I’m already looking forward to the next cruise… My responsibilities aboard centre around studying the flux of carbon and the main routes of carbon dioxide (CO2). Primary production (production of organic carbon compounds due to photosynthesis) is of course one of these main routes and the biggest part of primary production takes place in the oceans. If this work is purely fundamental, since the aim is to understand how the biosphere works, it is of course, even if indirectly, linked to the issue of global warming. Indeed, thanks to this small steps that help to understand a part of the functioning of the Earth, we will be able to better preserve it. This is the second consecutive year that I come to the PAP site to study the smallest of phytoplankton, picophytoplankton, and how they might contribute to the primary production in our oceans. These microorganisms are unicellular (one cell is the whole organism), are smaller than 3 microns (20 can fit on a human hair!) and are photosynthetic. One of their members is the smallest known algae, which measures only about 0.8 microns. Their abundance is usually low, but thanks to their high uptake rates, they can take up more carbon than cells of similar size such as the photosynthetic bacteria (cyanobacteria). During the last decades, these organisms have been poorly studied because of their small size and the general absence of morphological characteristics that may help to distinguish them. The use of molecular techniques circumvents this problem and allowed to discover a great diversity among these tiny organisms. Almost every two years, a new group is discovered. I collect samples at different depths using the CTD Rosette, to learn about their vertical distribution. In parallel, we measure different parameters, i.e. oxygen, temperature, salinity and nutrient concentrations. We do the same in other cruises to get an idea of the geographical distribution of this community of organisms. When we obtain a large enough data set, we will try to understand the relationships between the distribution of these organisms and the different environmental (physical and chemical) parameters. Another way to understand the diversity, the physiology, the metabolism and the ecology of these organisms is to isolate new cells. Last year I isolated a new marine class of these organisms that have been observed in freshwater systems but never isolated in the marine environment. However, thanks to molecular methods based on the analysis of the DNA, we start to detect these freshwater organisms in many oceanic regions. The isolation and culture process requires a lot of luck and efforts back in the laboratory to succeed to obtain a monoculture before being able to do further work on these organisms. During the last year, I learned a lot on how to grow these new cells and will use these skills to try to isolate them again and hopefully discover other members of the same class. The samples gathered the last few days will keep me busy for a while back in the lab. The expectation is exciting and motivating. What was on the menu today onboard the CELTIC EXPLORER? 23rd June 2007, 20.20 GMT Last Day
The PAP3 mooring is attached to a heavy anchor on the seabed. To make it come to the surface, we use an acoustic signal. This signal activates an opening mechanism and releases the mooring from its anchor. Once free, the mooring is positively buoyant due to the dozens of air-filled glass spheres attached all along the mooring line (what does a mooring look like?), and it floats up to the surface for us to collect. The glass spheres also have another role – keep the mooring line, and all the instruments attached to it, vertical so that we can sample exactly the depth horizons that we are interested in. A lot of effort goes into deploying and collecting such deep sea observatories and the samples are very valuable. If they are not recovered, it can be a depressing moment for many people involved (read how the drifting fishing lines destroyed the observatory during the Discovery 2006 mission).
The minutes slowly went by, we were searching the surface with spyglasses hoping that we can recover the samples which have been collected. Suddenly somebody shouted ‘There!’, but after a closer look it turned out to be a different buoy dancing on the waves far away north of the ship. So the search continued. Finally, there it was: first one sphere appeared, then a chain of yellow spheres suddenly broke through the surface and gently moving up and down with the waves. The PAP3 was recovered! After bringing the traps on board with their jars and their contents, new sediment traps were programmed and sent down again for another year of an automated collection of samples. In addition to the recovery of the old and the deployment of the new PAP3 mooring, the CTD Rosette was used to gather profiles of the water column. Later on tonight there will be zooplankton net hauls from different depths just like the night before. This will keep us busy until we leave the PAP site close to midnight GMT when our heading will be Galway Port, from where we left 5 days ago. What was on the menu today onboard the CELTIC EXPLORER? 24th June 2007, 20.20 GMT Until next time!
The scientists are working on archiving the data that has been collected, or packing the scientific material to have it ready for leaving the ship tomorrow. While we all consider our tasks more or less finished it is still ‘business as usual’ for our kitchen team James and Joseph who still have to feed 30 hungry people for another day and a half. In a good mood like always, James prepares our delicious meals even when the ship is swaying from underneath our feet. Tonight, for the last dinner onboard he will prepare steak for us! Until next time! Acknowledgements: |
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