In order to quantify the inputs from Greenland and quantify coastal currents, we wanted to have stations as close as possible to the coast. You can see on the map the location of our two coastal stations (bottom depth ~ 140-170 m).
The ice conditions are crucial to sail to these stations because the Pourquoi Pas? is not an ice breaker. We were very lucky: these areas were ice-free!
The scenery was wonderful! Icebergs, sea ice, Greenland coast, nice sunset and sunrise!
Temperature dropped from 6-7 °C to ~ 2°C, but the sun, which has been behind fog and clouds for long days, showed up!
Perfect time for a group picture and to relax on the front deck after so many days of hard work!
We are now in the Labrador Sea to start our last week of work.
Today is the 100th deployment of the classic rosette!!!!
The scientists and crew members are ready!
At each station, the first deployment is the classic rosette, the so-called CTD-Hydro. With this first cast, we have access, thanks to in-situ sensors, to the basic hydrological parameters, such as temperature, salinity, oxygen, fluorimetry, turbidity, etc… Samples are also taken from the bottles to calibrate the sensors in salinity and dissolved oxygen, as well as for other important ancillary measurements, such as nutrients, alkalinity, pH, dissolved inorganic carbon,…
Once in the water, the rosette is controlled from the PC container.
Don’t you think they look like little red korrigans when sampling the CTD?
To have a complete view of a CTD sampling, you can click here.
Salinity, dissolved oxygen, and nutrients are measured on board inside specific containers.
Dissolved oxygen is measured using the Winkler titration method.
During the GEOVIDE cruise, we study trace metals in the water, the particles and the atmosphere.
Some of these elements, the so-called oligo-elements, are essential for all living organisms (including human beings) and/or toxic. They are present at very low concentration in the open ocean and, in order to avoid the contamination of the samples, drastic conditions must be taken from sampling to the final analyses. For seawater sampling, we are using a “clean rosette”. We have posted already pictures of the “fish” for the collection of surface seawater and of the clean rosette deployment on the 18th of May and you can see a video on the “Videos” link.
Seawater sampling is then done inside the CNRS clean “laboratory”. We dress special clothes (Tyvek suits) to avoid contamination and look like cosmonauts!!!
12 bottles can be sampled at the same time.
Samples are taken for:
Unfiltered and filtered trace metals.
Size-fractionated particulate trace metals
Particulate samples are also taken using in-situ pumps, but this will be detailed later.
Fe isotopes
Mercury samples are analyzed in the IFREMER clean container.
For atmospheric samples, we collect both aerosol and rainwater samples.
Most of these elements will be analyzed back in the home laboratory.
Today is our second Sunday on board and we are doing our 21st station, which is a Super Station. The winch has been repaired and everything is back to normal!!!!
At this station all our equipments are deployed (Classic rosette, clean rosette, in-situ pumps, plankton net, and sediment corer). Typically a Super station lasts about 2 days.
It is timely to present you the “Bubble Lab” (see also the chronic in French). This lab was covered with plastic bags to help having it as clean as possible. The less dust we have there, the happier we are. This lab is dedicated to the treatment of in-situ pump samples. Thus we cannot allow particles from inside the ship to come on the filters where marine particles have been collected.
Before entering the lab, one has to remove his/her shoes.
In the first part of the bubble, the work that is carried out does not need the cleanest conditions. Samples are here taken for elements that will help to quantify the carbon export
Now we enter the cleanest and… warmest part… The air conditioning has been cut to avoid as much as possible any dirty air to enter!
In this part, the filters that are processed will be analyzed later in the home laboratory for the so-called “trace elements”, which means that their marine concentrations are as low as or lower than ~ 10-9 mol/L.
Here is the filter holder that is put on the in-situ pump.
The filter is then removed from its holder and cut in different pieces to be distributed in several labs for various analyses.
Catherine and Nolwenn do not play 4-hand piano but 4-hand cutting filters…
Between Wednesday and Sunday, the schedule progressed very well. Station after station, we deployed all our equipment (classic rosette, clean rosette, in-situ pumps, plankton net, fish, XBT, ARVOR floats). 10 stations were done.
First results start to come out!
At 3:30, Monday morning, the classic rosette winch got a severe damage. The winch unwound at 5 m/s instead of 1 m/s and there was no way to stop it… The rosette was falling in free-fall.
Hopefully the winch was finally stopped before the rosette hit the bottom and we did not have any wounded person!!!
Patrick, the engine chief and his team has worked very hard day and night since then to repair the winch. They successfully repaired it to enable putting back the rosette on board.
The big surprise was the bag of bones that the cable did just above the rosette.
Hopefully, the cable did not go around the rosette, which has not been damaged.
The difficulty was then to bring back the rosette on board, but this was successfully done by the Bosco and his team.
We were all very happy that the classic rosette could be brought back on deck!!!!
Additional tests had to be done on the winch. Instead of the rosette, a chain was put at the bottom of the cable and brought down to 1000 m. Unfortunately, the speed of 1 m/s cannot be reached anymore…
In order to lose as less time as possible, it was decided to switch the classic CTD from the bathy winch (front starboard) to the clean winch (back starboard).
At 22:30 Tuesday night, the classic rosette was ready to be deployed and the cruise could go on!!!
A small anecdote concerning this event: the winch damage appeared when the bottle # 13 was being closed. We were doing the cast # 13 of the station # 13 and we were at 13°W…
As mentioned earlier, our CTD for the classic rosette was out of order. This was very risky not too have any spare one, while sailing in the middle of the Atlantic.
Thanks to our colleagues from Vigo who lend us a spare CTD!!!! To have it brought on board, we sailed to the closest port in Portugal (Figueira da Fos).
The deployment of the clean rosette was a real success! This system allows the collection of seawater for the measurements of trace metals without any contamination.
It had been deployed for the first time since it was bought. A big thanks to Greg Cutter from Old Dominion University, who came to Lisbon to help setting it up before the cruise and give us lots of advises! We also borrow clean rosette from Norfolk in case the French system was not working, but so far, we do not need it. Keep the fingers crossed!
After collection of seawater, the sampling is done in a clean container to avoid any contamination of the samples.
During the cruise, we also collect suspended particles using in-situ pumps.
Thanks a lot to our colleagues Phoebe Lam from Woods Hole Oceanographic Institution, who lend us three pumps!!!
Everything is ready! We can sail. Bye bye Lisbon!…
Chief mate explains the safety instructions on board Pourquoi Pas?
In the afternoon, right after lunch, we had our first scientific meeting to explain the objectives of the cruise to everyone and to plan the first station, which will be a test station.
We arrived to our first station at around 3 pm.
The first equipment that was deployed was a CTD-rosette with which we collect seawater and other parameters (temperature, salinity, oxygen, fluorimetry, current speeds,…).
The first tests were not successful because the CTD was damaged. The damaged one was replaced by a new one and we could have it worked!
