Category Archives: Sampling

Messing up the mesocosms…all for zooplankton! (by Thanos)

Thanos processing samples after collecting the zooplakton

If you ever find yourself in the middle of a mesocosm experiment somewhere in the Mediterranean Sea and you decide to mess up with it, then you have only one choice. Call us. Call the ZMUT*.

We can do almost anything. We can do cubiing, pumping and sampling all free of charge ;). We collect copepods and their eggs and feed them with the soup from the mesocosms (each soup with different pH flavour), trying to understand how acidification of the seas affects those living creatures.

But the most important…

We are the only ones who can professionally mess up the mesocosms. The only thing that is needed is a net, just a common zooplankton sampling net.

And after that …

No microlayers, no samples, no filtration, no sediment traps.

Simple as that.

PS1: Our best wishes (double for those who are here from the beginning) for a safe return back home and for good results to all cubists of STARESO.

PS2: Thanks all of you for your help!

* Zooplankton Messing Up Team (ISO 2000)

Sediment traps, the best part !!! (by Amélie)

Mesocosms are like iceberg, the big part is underwater, the bottom is around 14m of depth and at the bottom of the bag there are the famous sediment traps.

Underwater view of the meso

I am in charged of sediment traps, they need to be changed everyday! It’s the best part of the mission, every afternoon I go with Sylvain to replace the sediment traps (which consiste in a plastic bottle screwed on the sediment particules manifold). We are totally independent, we go under water from the station to the mesocosms using underwater scooter, it’s so cool!!! It’s very fast around 20 minutes to go, change the nine traps and come back.

Sylvain and Amélie leaving the harbor to change the sediment traps

Under water it’s so calm (even when very windy at the surface), everyday we are welcomed by a multitude of curious fish.

We found a lot of swimmers in sediment traps and sometimes jellyfish!

The plastic bottles which are changed every day.
A jellyfish in the sediment trap!!

The sediment traps collection is done to measure the export of organic and inorganic carbon and see if there are differences between treatments.

I would like to sincerely thank Sylvain who come with me everyday and Alex (the Sunday afternoons) as well as Stephen who took a really nice pictures of mesocosms.

…THE DAILY JOHNATAN’S JOURNEY.. (by Francesca and Cinzia)

I have been spending almost one month in the wonderful Stareso station, working in the mesocosms and it is revealing a really great experience! Some are happier some are less to go back home, however tomorrow will be the last day of the experiments…I did a lot of “in situ” work because my parameter’s analysis can not wait (at least for CDOM). But today I am not going to bore you about my analysis!

I would like to tell you a little story about..our Johnathans (the name we have given to the integrated-sampler-bottles)! Because Cinzia and me we will miss them a lot..

I am in the daily team of 8.30 am with my collegue Cinzia, so every morning we are full of energy (well, coffee is strictly necessary..) to go to the cubis for sampling K3! This the best moment of the day (as far as work is concerned..), because one of the Johnatans is randomly with us 😉

(Cinzia and Francesca at 8.30 team on cubis)
When we approch the mesocosms and we are well attach by ropes (if not the strong SW wind will blow us to Genova or Sardegna) we are ready to prepare our Johnatan for his journey into the so transparent and blue corsican waters…

He will travel in the water-column until reaching 10 m depth: we cast him very constantly, slowly and sweetly by the rope, in order he is able to collect the integrating seawater we need.

Basically is like a big 5 Liters syringe. Thus, is very important to push down the piston before casting again.

Since Samir and Fred smartly discovered the utility of the “push botton” to save time in the meanwhile we are sampling the last bottle (the pressure is higher) we also enjoy with the rest of the team to sing “Me gusta el push!”

The PUSH “moment” standing on knees

The name alludes to seagulls that unfortunately made their dwelling place above the roof of the mesocosms..
“If you love someone, set them free..If they come back they are yours..if they don’t they never were.”

Nutrients sampling

The Mediterranean Sea in general, and the Calvi Bay in particular, are very oligotrophic areas. As a result, organisms living in their waters are adapted to low nutrient concentrations, and even small changes in these concentrations can cause big perturbations of natural communities.

Thanks to the mesocosm experiment, we (Sylvie Gobert from University of Liège, and Loïc Michel, from the Stareso research station) will try to understand if ocean acidification could modify nutrient concentrations in Calvi Bay. To do so, we take daily samples to monitor nitrates and nitrites, ammonium, phosphates and silicates concentrations in each of the mesocosms, as well as an “extra” sample out of the mesocosms. We look forward to seeing which trends emerge from the data, and we hope that they can be useful for other scientists taking part of the experiment too…

Once the water is sampled, we have to condition the samples. This is the most critical part of our jobs, because by this time, it is usually around 11 AM. Since labs are quite crowded, we work directly on the Stareso dock, under the burning Corsican sun. During this dangerous task, the only things that prevent us from baking are 1) our beloved straw hats (see fig. 1) and 2) a very good hydration plan based on refreshing Corsican beer. After conditioning, we place the samples in the freezer (for NO2- + NO3-, NH4+ and PO43-) or in the fridge (for SiO44-).

Nutrient conditioners hard at work under the Corsican sun.

Now the experiment is nearly finished, and nearly all samples are stored, patiently awaiting analysis. On Sunday (July 15th), our colleague Renzo Biondo (also from Lab of Oceanology, University of Liège) will join us, and we will start the analysis step. All nutrient concentrations will be determined at Stareso, using our Skalar automated continuous flow automated analyser. Methods differ for each compound, but all are based on colorimetric detection. When everything runs smoothly, this type of analysis is rather quick, and we hope to be done in about a week… However, the analyser is a whimsical machine, and a lot of things can go wrong. To ensure that the Nutrient God is with us, we consider sacrificing one of the station’s cats to him. Let’s hope it will be enough to please him!

(NOT!) gone with the wind!! (by Cécile)

Sampling with wind conditions at least 15 kt has become very usual for the MedSea mesocosm team and we are now able to work such very difficult conditions. It is amazing and the participants are amazing on their cubi. We have put diving weights in the samples boxes to avoid any flying boxes to the water! Yes, we have been experiencing high winds since several days now and yes, we are ok but most surprisingly, the mesocosms are still in very good shape and no damage were found by our diving team (Amélie and Sylvain) who go to the mesocosms everyday to change the sediment traps. As they go under water from the Stareso station using funny ‘underwater scooter’, they could go to the site, even yesterday. They said it was very nice and calm at 15 m depth! Indeed yesterday, the wind was so strong that we were not able to go out with the boat as the security was concerned. We have been deciding on the sampling strategy by following very carefully the forecast: for those who are used to sail in the Med Sea, they know as the wind can change rapidly, and as it can increase its speed even more rapidly. We have a ‘Special Forecast Warning’ since 4 days now and it seems difficult in the present condition to predict what will really happen in term of wind …. Apparently, the worse has to come as they predict a huge wind event for tomorrow (figure from… Huh, no doubt that tomorrow will be a quiet day in the labs, except for the incubated samples that hopefully we will be able to withdraw quickly with the rubber boat early tomorrow morning!

Here is the forecast map. Corsica is surrounded by red wind areas! This is for tomorrow (Sunday) at 12pm.

Apart from being quite annoying for our daily sampling routine, this event is going to be very interesting in term of results as a specific forcing on the structure of the surface mixed layer, on the air-sea exchanges and on the functioning of the ecosystem.

CTD (by Anastasia)

CTD (standing for: Concise and Terribly Distressful)
Date of birth: end of 2011
Place of birth: Washington, USA
Parents: Raquel, Angela, Grigor and Vincent
Siblings: The Radiometer


-Handle the CTD with immense care and don’t rush it!
-A good teacher (while on the cubi) will definitely help you take accurate measurements and will explain in depth the principals of its use, unless singing/listening Greek songs distracts him!
-Singing in general will help you a lot to concentrate and find the perfect – appropriate rhythm for lowering the CTD in the water
-Use an umbrella while using it and hide below it, in order to protect from light (and be fashionable!)
-Drift with the currents and trust the waves when “travelling” from one cluster to another, without being attached to any of the ropes. Oops! If the weather changes unexpectedly and floats you towards Calvi, jump in the water and save the CTD!
-Don’t panic! Instructions for correct handling are given on board the cubi. Try to keep calm
-Real time data will only come after a quite long processing day that requires patience and … knowledge of course
-Rinse the CTD with water (and affection…) immediately after each use and, if necessary, forget about your lunch

Vincent and his second baby

Principal(ok, let’s be a bit more serious now!)

The CTD (actually standing for Conductivity, Temperature, Depth) is an instrument that takes continuous measurements of several water characteristics (temperature, conductivity – from which salinity is derived -, pH, fluorescence of chlorophyll pigments, photosynthetically available radiation, and dissolved oxygen concentration), with the use of sensors that are placed whether in external or internal flows. It provides you with a detailed description of your water sample, with measurements taken four times per second. These measurements are then aligned to depth (by converting pressure to meters) and are saved in digital form in order to be processed later…

An Early Morning Treat! (by Lisa)

As I live in one of the wettest and windiest areas of the UK, some might say that I should be well able to cope with gusty weather!

However, I don’t think anything quite prepares you for the experience of balancing yourself, your sampling boxes and the integrated sampler on a floating plastic cubi in gusts of 30-40mph. Being somewhat inelegant at the best of times you can only imagine the resulting chaos! Trying to negotiate guide ropes and pulling yourself close enough to the mesocosms to enable the safe deployment of the integrated sampler whilst battling against the wind gives the added benefit, for this unfit scientist at least, of a full-body workout!

It was somewhat gratifying therefore to arrive on station early this morning in order to collect my 24 hour incubations (for nitrogen fixation and nitrification) and find a flat, calm sea with the sun just appearing over the horizon.

The incubation lines are set up as close to the mesocosms as possible in order to replicate the conditions (light, temperature etc) within, whilst at the same time causing as little interference with the guide ropes and the mesocosms themselves. Cecile and I headed out for the lines, both saying little and just enjoying the peace and tranquillity. After a brief panic of thinking my bottles had broken free (they weren’t on their usual lines!) we were turning around to head back in when Cecile said “Oh wow, look at that!” Thinking she was referring to the amazing sunrise I replied “Yes, it’s stunning isn’t it?” “No, look! It’s huge! Is it a whale or a dolphin?” she replied. Not having my lenses in it took a while for me to focus (hey, it was early!) It was then that I noticed two groups, fairly close together, of what appeared to be fairly dark coloured dolphins. We edged slowly forward in order to get a closer look and just stood and watched in awe as the groups joined together to play.

After starting to come back in, we then became concerned that the dolphins may have been attracted by what I had been told were fishing nets and might get caught up in them. We turned back in order to make sure they were okay and watched as the little family swam out further to sea.

What an amazing experience, and a perfect start to the day!

Improving our cubis style

Since yesterday the wind weakened in Stareso area but that mean the sun is harder to support! For the early morning sampling it isn’t a problem but for the 8.30am, 10.30am and instruments samplings it’s hard to stay 2hours in the cubis without sun protection. As it became to hard for Vincent and Raquel they’ve decided to bring a sun umbrella on the cubis and here is the new cub is style (click on the picture to see the video made by Louisa during a sampling):

Today we also had to remove all our empty boxes stored outside: an helicopter had to land at the station 15min later! It was spectacular to see the landing and takeoff in a so small area!!

Sampling the Sea Surface Microlayer (by Alina)

While we wait for the mesocosms to be acidified, a Saharan dust plume came across the Mediterranean Sea. Since the sea surface microlayer is heavily affected by atmospheric influences, I took this downtime as an opportunity to get some samples outside the mesocosms in hopes of seeing large differences between the microlayer and the water column below with regard to trace metals.

I have devised a new sampling method to get microlayer samples for trace metals.  The sampler is a quartz tube that is dipped vertically into the water; then slowly raised out of the water vertically. The water that drips off the tube is, in theory, the microlayer and is collected into a funnel that is connected to a receiving bottle.

Cécile and I were joined by Karine and Clémence, who study aerosol formation from surface water bubble bursting, in a small Zodiac out into the Bay (well, Karine swam and Clémence took a kayak).  Once we got to the site right off the coast, Clémence and I switch places and soon I was sitting in the kayak with my bottles and microlayer sampling apparatus.  I have never thought of using a kayak before, but it is actually the easiest thing I’ve used so far (besides standing in a lab sampling from a tank, that was pretty easy)! At first Cécile was going to help hold things on the kayak, but we thought better of it after she hopped onto the kayak and nearly flooded us out of it. So, despite having soaking wet pants and my arm being very tired, sampling was great and I could not have asked for a better team!

Alina sampling for the microlayer trace elements