Sailing on familiar yet unknown waters

August 2019

Joost Mansour and Andreas Norlin, MixITiN ESRs, report from somewhere on the Mediterranean sea

Ready As ever!

Last June we (Joost Mansour & Andreas Norlin) found ourselves again headed to the Côte d’Azur. This time, though, we would not touch land for the coming two weeks. We had the opportunity to board Research Vessel La Thalassa for the yearly MOOSE oceanographic cruise. MOOSE-GE (“Grande Echelle”) is one component of the Mediterranean ocean observing system. The MOOSE-GE (“Grande Echelle”) covers the North-Western Mediterranean basin and is one component of the Mediterranean ocean observing system for the Environment (MOOSE). Which has an overall objective to observe long-term changes of the Mediterranean Sea focusing on climate change and anthropogenic pressures. Data gathered during the cruise will be delivered as open data and information, to the main European data portals, to be used for marine research and public policies.

As this is mainly an oceanographic cruise it allowed us to learn some new things about oceanographic wet research. Following the transects, a CTD operation was going out almost 24 hours a day, surface to bottom, to collect water samples. Water samples are collected at 21 depths – easily taking 2 hours for a return trip – to measure parameters like Temperature, Salinity and O2, fluorescence, particle size abundance. The occasional ‘special’ CTD added extra measurements for plankton species image acquisition, nutrients, dissolved inorganic carbon and phytoplanktonic pigments.

We took the southern routes, which is all the stations starting with a ‘2’.
Last sight of land for the next weeks.

The morning CTD’s usually included a ‘BIO’ station, which was where we mostly came in. Every year, the Station Biologique de Roscoff in collaboration with MIO (Institut Méditerranéen d’Océanologie) and Observatoire Océanologique de Villefranche sur Mer do genomic sampling of the plankton and bacterial communities of the Mediterranean. In the Mediterranean there does not exist any complete time-series data set for these communities. The monitoring of biological community structures over time will give important new insights into the development and change of these communities.

wet lab
The wetlab is fully prepped for incoming CTD and sample filtering.
CTD prepared, let us send it off into the depths.

Part of the samples came from the Niskin bottles going down with CTD operation. These are mainly used for the assessment of bacterial communities. During the ‘BIO’ station – which for us were the most exciting stations – we additionally deployed several nets. These were for the sampling of different size fractions and subsequently filtered and fixed with different methods. Each method serving its purpose as the best fixing method for the prospected analysis. Doing this as fast as possible was our (Joost, Andreas, Thomas (from MIO)) challenge during these stations. Of course, this was for good DNA/RNA sampling, but also to have a good amount of time with subsequent live samples.

Water samples were taken to our private lab at the lower deck of the ship. Here we could search for our familiar Radiolaria and try some feeding experiments with stable isotope enriched prey. It also allowed us to show the wondrous world of plankton to those less enlightened (see also our Beautiful Radiolaria pictures in our previous blogpost or on twitter).

Best moment of the day… putting the net in the sea

Besides all the stations and work, we had the time to enjoy shipboard live. The pictures below tell the story better but…summarised it was something like this:
-time to burn in the Mediterranean sun;
-get safety training;
-enjoy great food, lunch and dinner alike;
-see the ships insides;
-getting greeted by pilotwhales.

Moreover, to keep the science going there were daily seminars, where we also had the chance to introduce mixoplankton to scientific (non-biologists) and nonscientific crew alike.