RV Belgica cruise ST1017b

Cruise blog: 18 - 27 June 2010, Whittard Canyon

Friday 18 June
Saturday 19 June
Sunday 20 June
Monday 21 June
Tuesday 22 June
Wednesday 23 June
Thursday 24 June
Friday 25 June
Saturday 26 June
Sunday 27 June

Friday 18 June 2010

1_turtle

The day before the cruise. Scientists are arriving and arranging their cabin for what will be a relatively short research cruise. For the next 10 days, we’ll be aboard the RV Belgica on a Canyon adventure along the Irish Margin. Today, people are venturing into the centre of La Rochelle to enjoy their last hours on land. A visit to the La Rochelle Aquarium was arranged for the scientists. The director kindly gave  some enthusiastic scientists a guided tour through what came across as a very nice and well-organised aquarium centre. In a few hours we travelled through the North Sea, the Pacific, the Caribean Sea and other theme-based exposition areas to be confronted with the wonders of our oceans. The climax of our tour was a visit to their sea horse cultivation centre and the research and care sentre for sea turtles. Currently, a sea turtle that was washed ashore, exhausted due to an infection, is getting treatment. Perhaps in a few months time, this lovely animal will get another chance to roam the oceans.

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Saturday 19 June 2010

3_shipAfter the arrival of our PI for this cruise, the Captain and crew were getting ready to steer the ship out of the harbour, heading for the Whittard Canyon. Earlier this morning the scientific equipment was removed from the cargo room and stowed away in the laboratories.

Following daprture was the first lunch of the cruise. A nice example of how the cook of the ship can make everyone happy. It promises to be a good cruise as the Captain informed us of good weather lying ahead.

Today, scientists and engineers have already started working. Clearly eager to get things ready, the ROV engineers have started assembling a push core rack onto the sampling tray. Creative as they are, a  few changes are made to the valves closing the bottom opening of the cores. The whale watching crew have settled on the Monkey Island on top of the bridge. Their task will be to report and note any whale sightings. Everyone is excited, the sea is flat and visibility is great, perfect conditions for spotting marine mammals. During the afternoon, the ship will pass by “Plateau de Rochebonne”, a group of submarine hills nearly reaching the sea surface. Primary productivity is known to be very high here and ensures a rich ecosystem often attracting different species of birds and whales. Sounds very promising, but unfortunately, no mammals to be seen, apart from those holding binoculars whilst staring in the distance.

All scientists had a safety breef, which was followed by a science meeting in the mess in the presence of the Commanding Officer and the Executive Officer. A preliminary plan was presented for the ROV and Multicore (MUC) work and shifts were divided. In summary, the main aim of this cruise is to collect ROV video transect data and push-core samples of the sediment, water column samples by means of CTD and Niskin casts, and MUC samples to characterise the biogeochemical sedimentary environment and the benthic fauna.

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Sunday 20 June 2010

4_whalesToday the sea is calm, perfect for whale watching, but also for getting everything ready and set up in the labs. ETA for the first ROV station is Monday 4am.

The CTD equipment needed to be tested. A link between the CTD and the lab computer was set up, data from last leg was downloaded, checked for errors, and the system batteries were replaced. All seemed to work. Only a slight error during the data transfer occurred, but this can repaired. It was decided that CTD data will be uploaded every evening to check for errors and avoid loss of data.

Later, a CTD test was performed down to 1300m water depth. Irregularities in the retrieved data compromised further use of the CTD. Contact with BMM was made to find a solution.

In the afternoon several dolphin and whale observations. 7 to 8 groups of dolphins (ca. 125 individuals, species to be confirmed) past the ship. A mother and calf of fin whale was observed.

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Monday 21 June 2010

6_rov_room8.00 ROV dive 3 (First of the 2nd leg) point 1a to 1b. Going across levelled sedimentary environment. High densities of pennatulids, fish, and occasional holothurians, echinoids, seastars. 1 succesful PUC taken, which was recovered for meiofauna analysis .2nd part of this dive took us across very variable topography. Dead, hard corals on top of ridges, slopes covered with pennatulids, with occasional fish (Chimera, other spp.) echinods, seastars. Some octopusses, and 2 sharks!

9.00 Sperm whale observation and shark and sunfish at surface

12.00 ROV dive finished. 2nd part of dive was difficult terrain to navigate through. Constantly up and down slope with many small gully features. Low current activity, no ripple bedforms and constant particle flow (marine snow). Soft sediment was easily resuspended when contact with bottom. Clear evidence of fluff layer on bottom sediment. Relatively high faunal densities.

12.30 ROV dive 3, 3rd part of dive: point 1c to 1b upslope. Similar geology and fauna observed as previous part of dive. Topographical very variable terrain with steep slopes and walls. All topographic features were covered in (fine) layer of sediment.

After ROV retrieval problems were encountered with ROV stills camera and new video camera communication. CTD did not appear to work properly, so decided to switch to seismics unitil the ROV is operational again.

In the afternoon, preparations were made for MUC sampling procedures.

Seismics will continue until the morning (8am)

In the evening contact was made with the RRS Discovery which was operating in the Whittard Canyon as well. On their route to Ireland they were performing pelagic sampling and side scan surveys to investigate internal waves along the Celtic Margin. Very interesting, since the location corresponded those where we ran our ROV survey and seismic operations. It would contribute greatly to our understanding of geological and biological processes in the head of this canyon branch if we could correlate the data gathered by both scientific parties. A multidisciplinary approach could prove very succesful.

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Tuesday 22 June 2010

7_crewSeismic operations ran until ca. 9.00 am after which course was set for the deepest CTD station. ETA just after 10.00 am. Preliminary seismic data at the head of the western Canyon branch showed thick sediment layers covering 2 channels cutting into the edge of the shelf. Initial interpretation indicates a hydrodynamically fairly inactive canyon head, which corresponds with earlier ROV footage (no ripple bedforms, undisturbed sediment coverage) and infauna results from the Belgica cruise in June 2006 (sediment covered in fluff layer with undisturbed surface layers indicating very low disturbance frequencies and intensity, corroborated by the faunal assemblages which seemed adapted to suboxic conditions, which in turn could be an indication of high organic matter input and low rates of disturbance reoxygenating the sediment). Lots of soft corals

ROV engineers are still investigating the communication problems with the stills and one of the video cameras.

CTD problems continued for some time. A first test at 1000m showed errored data. Reconfiguration was attempted and a second CTD deployed. It worked! Second CTD was succesful and the decision was made to complete the CTD casts at the background site and the 5 station transect in the Western Canyon branch originally targeted. At station two the CTD winch got stuck with the CTD at 900m depth. CTD was recovered but whinch was in need of repair.

The MUC was assembled on the after deck in preparation for tomorrow

The ROV team was able to repair the communication with the stills and video camera, ROV operations will commence on Thursday.

In the late afternoon seismic survey started and will continue untill the morning.

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Wednesday 23 June 2010

8_scientistsMUC and CTD operations started at 9.00. A transponder was attached to the MUC frame, together with a CTD module. Attachment of the transponder and the use of the GAPS enabled precise localisation of the MUC in the water column and on the seabed. The rhizon cores did not seem to fit the original corer heads, the core tube rings were too wide,precluding closure of the safety ring. After the first deployment of the day we decided to put on the spare new core head, in which the rhizon cores fitted. At the first station the MUC was deployed 4 times, with a success rate of 9/16. No specific problems were observed and we think the seabed topography or penetrability of the sediment was mainly responsable for the failure of some cores. In the afternoon,  the next station was reached, in the thalweg of the western branch. A total of 4 drops was attempted, retrieving 5 sediment cores in total. Low success rate was due to high patchiness with prevalence of hard clay, rocks, boulders and sandy patches. MUC operations were terminated at 20.00.

CTD was removed from MUC and attached to the CTD frame. During the first CTD deployment winch problems occured once more (shackle problem). Problems were solved and two further CTD deployments were completed.

Seismics started at 24.00

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Thursday 24 June 2010

9_coralAt 8.45 the ROV  TMS was deployed for dive 4. The ROV video showed seabed areas that obviously had been trawled in the past. Areas with dead corals, mostly coral rubble, and trawling marks indicated human’s impact on the seafloor. As if the sight of  the destruction wasn’t enough, a few moments later fishing lines got caught in the TMS. Worried looks in the ROV van.  Attempt to put the ROV back into the TMS failed partially. The fishing lines and attached corals got entangled in the TMS, ROV and umbilical winch. These situations can be very unpredictable as the fishing lines can be very long sometimes get sucked into the thrusters. The decision was made to stop the ship’s propeller to avoid damage to the ship. The ROV was partially sticking out of TMS upon retrieval. TMS and ROV on deck at 12.00. A large amount of fishing lines with attached hooks, corals and associated organisms were retrieved from the frame. The scientists on board could not hide the excitement, but also a sence of despair of what just happened. Anthropogenic impact is not just seen underneath the water surface, many birds were seen flying around with fishing lines, hooks and pieces of rope attached to their beaks, neks or legs.

ROV and TMS were operational at 14.00 and deployed for dive 5. ROV back on deck at 16.00. Transition to next diving site. Dive 6 started just gone 17.00 and was back on deck at 21.00.

What followed was a CTD in the evening and seismic survey during the night.

Tomorrow is going to be a “muddy” day. The gear for the biologists was prepared for a day of multicoring. In June 2006 we had succesfully sampled at the same location. Even though the MUC was only semi-operational at that time (2 working core heads instead of 4), we were still able to get sediment samples for biological and environmental characterisation. So the anticipation of a long day of work was present, and we were all hoping that undisturbed cores filled with muddy sediment would land on deck.

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Friday 25 June 2010

10_corerSteak béarnaise and fries, berlin buns with self-made custard, home made cakes with cream and cherries, they really do feed us very well. The cook’s and steward’s efforts are always greatly appreciated.

A very succesful MUC day today, the cores were landing on deck quickly. The team was working hard getting all the cores sliced before the next load arrived. First on the list was a site were cores were selected for two experiments. The aim was to investigate the active and passive dispersal with nematodes. In canyon environments resuspension of the sediments through currents and other hydrodynamical features occurs quite frequently. The experiments were designed to investigate whether nematodes,when resuspended with sediment, can actively choose where they settle down as ‘particles’. In a patchy, heterogeneous environment such a strategy may be crucial for organisms which do not have an pelagic life stage.

In the centre area of the channel, the thalweg, thick grey clayey mud was observed, mixed with sandy turbidites and small rocks. A very different picture compared to what was retrieved from the walls of the canyon. Evidence for patchiness and high within-canyon heterogeneity. During the MUC sampling sessions, a cross transect was achieved which will enable us to describe the meiofaunal and biogeochemical heteregeneity in this branch of the canyon system.

The intensive series of MUC deployments that day kept the scientists indoor processing the cores. All work was finished by 22.00.

Everyone toasted to the success of this campaign, the blessing of the weather and the good transit back to the harbour in Zeebrugge, Belgium.

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Saturday 26 June 2010

12_bbqNo after deck work anymore. Only the whale and bird watchers are on the monkey island to observe whilst steaming homewards. In the climate room, 2 experiments were started up the day before. The incubation was regurarly checked and a first experiment was processed today.

The scientific crew started cleaning and packing all the gear, making maximum use of the transit time.

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Sunday 27 June 2010

13_sunset_seaThe last day of the cruise. Everyone is in good spirits, people are finishing packing and cleaning. All samples are put away in boxes.

To finish off the successful cruise, the captain adressed all crew members on the after deck, followed by a barbecue in the baking sun surrounded by a mirror sea. ETA Zeebrugge, Monday 28 June 2010, 08.00.

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Jeroen Ingels