Monthly Archives: June 2012

back from the beautiful Corsica Island (by Patrizia Ziveri)

Working in the mesocosms and the mesocosms under water
I am back from the beautiful Corsica Island where I went during the preparation and starting of the MedSeA mesocosm experiments on acidification, off Stareso Laboratory near Calvi. This is an important event for the MedSeA project and for the theme dealing with the “Effects of ocean acidification and temperature on pelagic ecosystem function”. We are testing for the first time in the Mediterranean Sea, future acidification scenarios on microplanktonic organisms and key biogeochemical processes. This is very exciting and it was good to see that the testing went well and the actual experiment is started. There is a great group of people, all very motivated, excited and hard working. The people from LOV in Villefranche, led by Frederique Gazeau, are doing a great job in keeping everything under control and building a good and efficient sampling planning to make sure that the experiments will be successful.

I looked at same samples from the mesocosm by scanning electronic microscope and there are coccolithophores! (several species but all quite small and in different stages of their life cycle). These are very interesting samples for Angela’s PhD project.

Coccolithophores from Stareso!

All the best to the mesocosm team for a successful sampling and great results!

A kukurukoo story made by Aggeliki

My last day today and feeling kind of sad that I am going, knowing that I leave work behind for my colleague Anastasia and good friends that I met during my stay. It was a pleasure. Somewhere between the hard work we had our moments…our moments of silliness. We managed even to laugh with our mistakes especially during the tests on how to sample, how to save the boxes when they fall in the water, how not to let go the rope because you start your journey to Genova…Oh we helped…we helped Villefrance team to realize almost anything that could go wrong on the cubi (platform). But as I said we laughed and I use the word kukurukoo for each silly action.

Trying to explain this to our colleagues here was some kind of difficult. Thank fully Raquel helped me a lot. She did the best kukurukoo action of the experiment so far. This is how the story goes:

We were all having dinner as usual, all together with our trays and plates in order. That day was the days that Patricia Ziverri (MedSeA coordinator) had arrived and by coincidence she was sitting near us and she was making polite conversation with all. Out of a sudden, Raquel with her poor English but with a beautiful heart says to Patricia: ‘Hello, I am Raquelle, and you??’ Patricia replies politely: ‘I am Patricia, how are you doing’. Raquel replies: ‘I am well, thank you. Are you working with us???’……at that point we all froze and stared at each other…It was then that Francesca said to Raquel: ‘She is the coordinator’…..And after that awkward moment passed, we started laughing so hard because Raquelle had explained in a really good way what kukurukoo is…….

Will miss you all

Aggeliki

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!!

… and the experiment started!

After a long preparation, mainly done by the Villefranche team, and some days of test samplings were we all learned how to deal with the ropes, the platforms, the hydrobios integrater sampler, pumps etc, each of us have already sampled for its own data. During this preparation we had some troubles (mainly in the windy days). For example, the pump used to acidify felt once in the water (luckily it was saved), one of the carrying boxes with all the empty bottles also felt in the water in a windy day, but after a refreshing swim it was saved as well. Some of the scientist also felt in the water but came back swimming and finally, one team was caught in pictures when, unlocked themselves from the mesocososm units and, taken by the currents, started to drift in the platforms… soon they were brought back by zodiac.

Sample team is brought back by boat after drifting with the currents. On the platform they were probably just enjoying the little trip 😉

All these experiences made us stronger and ready for the real samplings and subsequent processing of the samples. In my case it meant filtering about 80 liters of water. These because I want to see coccolithophores, marine calcifying phytoplanktonic organisms that are at the base of the food web and particularly sensitive to the changing ocean carbonate chemistry. Coccolithophores produce plates (coccoliths) of calcium carbonate which they use to cover their bodies (single cells).

For these organisms, a decreasing pH of the ocean is expected to affect the production of calcium carbonate by coccolithophores (see Image from Beaufort et al. 2011 article where evidence from sediment samples seem to agree this hypothesis). From each of the nine mesocosms I will be filtering 9 liters of water to later observe the filters under the scanner electron microscope (SEM). I will check whether those coccolithophores living in the more acidic ambient have more malformed, incomplete or thinner coccoliths than those living under normal conditions (in the Mediterranean “normal” means high alkalinity and saturation state for calcite, impeding the dissolution of calcium carbonate). Half of the water will be used to measure Ca in the smaller than 40um fraction (if I manage to get sufficient material). First samples are in the oven!

Modified from Beaufort et al. 2011

Les radeaux de Stareso…

After 5 days of delay, we finally really start the sampling!! To place the events, last week-end the mesocosms tangled in the ropes and water went out of the bags. We had to re-open the bags wait one night close them again and start the acidification step by step during 3 days. The last acidification was on Saturday and to be on time we had to work late the days before (till 11pm sometime!).

The zodiac with the broken board and motor nearly on the seawater!!

So, yesterday (Time 0) we had the first departure at 4am to sample the processes. Well, in theory was 4am but…Louisa, Anggeliki and Mauro didn’t wake up!! Hopefully they don’t sleep in the lighthouse so, we could wake them up and we left only 15min late. But the teams on the sampling platforms were efficient and we arrived at the quay at 6.30am which was more or less the time expected for this team. Not even the time for a coffee and we prepared the vials for the incubations and other.
Fred and myself (Laure) we had to fill 8 vials of 60mL per mesocosm, inject “heavy water” (it’s water with 18 oxygen) in 5 of them and fixe the 3 others for the initial values. Then we incubate the 5 vials during the light period, phytoplankton will split this marked water to O2 by photosynthesis. Later in the laboratory we’ll be able to quantify the production of marked O2 and the decrease of marked water and so, have the Gross Primary Production data. The incubations are done near the mesocosms at 6 meter depth (half of a mesocosm).
The day wasn’t finish and we had a last important step to do: the addition of few grams of heavy stable Carbon (Carbon 13) which will allow us to follow the Carbon in the community.

The boats we use to go to the working area (=the mesocosms): the kayak; the zodiac and the Mini-Jeanne (and the biggest one is the Marie-Jeanne but we don’t use it).

Stop for the “science” and back to the event of the day: le radeau de la méduse. Yesterday, as a big day we had our first problem with the zodiac. While Vincent and Raquel were coming to the mesocosms to run the CTD (instrument to measure many parameters at the same time directly) the board on which the motor is kept broke!! they managed to join the Mini-Jeanne (the boat of the station) but we can’t use the zodiac anymore! We’ll to do a more extensive use of the kayaks to compensate this lost.

Winkler Method (by Walter)

Background
The oxygen is a fundamental element for the live in earth. The his amount in air, and in oceanic superficial layer, is 21% in constant balance in gas exchange air-sea.
The Winkler method is a test to determinate the concentration of dissolved oxygen in water samples: the quantity of dissolved oxygen is one of the measures of biological activities in seawater or freshwater. It’s necessary also, for example, to study water masses in the ocean or to measure the redox potential in water column. This test was originally developed by Lajos Winkler, an Hungarian analytical chemist, in 1888, modifying a preceding test. Winkler discovered a safer and more precise method of dissolved oxygen analysis thanks to an iodometric titration.
Carpenter in 1965 modified the Winkler method for analysis of dissolved oxygen, because he found some particularities about accuracy and errors, like air oxidation of iodide and volatilization of iodine, oxygen contributed by the reagent solution, iodate contamination of the iodide solutions, consumption or production of iodine by reagent contaminants, difference between titration end point and the equivalence point.

Principles of analysis
The production and respiration rates of microbial community will be calculate by variation in amount of dissolved oxygen in a defined time and comprehensive of all organisms activities in samples (autotrophs and heterotrophs).
The samples taken from mesocosms, will be fixed with a sequence of MnCl2 and NaI, resulting in a brown precipitate, and will be preserve a part in shadow and a part in light at same sea temperature on 24 h. The difference on amount of dissolved oxygen between T24 and T0 in shadow gives an estimate of planktonic respiration, a biological process of all organisms (in our case planktonic) where it obtains energy from oxidation of reduced organic compounds, realising CO2. Instead, the difference on amount of dissolved oxygen between T24 and T0 in light gives an estimate of planktonic production, a biological process of organisms that produce, by photosynthesis, organic molecules from carbon inorganic, by a reduction reaction, realising O2 (the photosynthetic organisms, primary producers, are at lower trophic level, supporting the total ocean and terrestrial life forming biomass).
After the incubation, it will be necessary proceed with a iodometric titration, because one mole of O2 reacts with four moles of thiosulfate and, by calculation of amount of thiosulphate, it’s possible calculate how many dissolved oxygen is in samples. Here I will try to explain shortly how.
Prior to start the analysis, it’s necessary standardize the titrator with a standard solution of KIO3 (potassium iodate), to minimize the error of the machine and to know the right concentration of the titrant solution. Moreover the sample is acidified with H2SO4 (sulfuric acid) to dissolve the hydroxides precipitated (MnCl2 + NaI) , liberating elementary iodine (I2) that reacts with surplus iodide ions, forming a complex (I3-) that is titrated with sodium thiosulphate. The total reaction is this following:
2S2O32- ↔ I2 ↔ ½ O2

Phases of the method


Calculation and expression of results
With the iodometric titration, the titrator by the Tiamo software calculates the amount (equivalent volume) of thiosulphate that is necessary in titration at equivalent point of our samples. The calculation will be done by Excel, in which considering the real volume of bottles (approximately 50-60 ml) and putting the equivalent volume, by a formula it’s possible know the right oxygen amount (μmol/L). Furthermore, calculating the mean and standard deviation, crossing the fingers, we can do some considerations about our results.

Winkler Team

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

Acidifying!

It was mentioned before that acidification is being done gradually, well..today it was my turn to join one of those steps!. First Frederic saturated the big water tank up to a million ppm CO2. Then we filled the “little” 20 litter bottles and put them in the boat together with the “spider” that looked more like a fine shower, few things more …and ready!

Fred preparing the CO2 saturated water
It was a windy morning so the platforms were moving a bit, we placed all bottles on them and after a little struggling we managed to arrive to the mesocosms. We pumped 40 litters in one and 60 litters in another. We even got a few time to chill out while pumping ;)And on the way back: frijoles! beans! were waiting for us.

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My first days in Stareso by Louisa

As preparation days go by, everything seems in order and everyone is more relaxed knowing exactly when and where they need to be. Thus, I (Louisa) among the participants start to enjoy the vicinity and the local cuisine. The food so far is superb with paelia the first day, mixed grill the second and so on…the breakfast is a bit poor…I would love to have croissants but this is already an expensive mission so no need to overspend on small luxuries ☺ We still enjoy to dive off the peer whenever we have free time. Of course avoiding the spot where Andy was bitten. We don’t want to disturb the eel.
On the first day in the afternoon we start cleaning the cubi (the plastic cubes that form the platforms). At first by throwing buckets in the water to collect it and water the cubes while Francesca, Walter and Lisa where rubbing them with brushes. Unfortunately, this was time consuming so Laure, me and Francesca fell in the water while the others were throwing the cubis to us to clean them in situ…more efficient and more effective. In parallel, the rest of the participants were preparing for tests. My oxygen tests were also waiting me to improve them.
On the second acidification day (Wednesday 20th) in the afternoon, Fred and me went on the mesocosm (Cluster K3, P6) that has to be the more acidic. We had 9 bottles of 25 liters of seawater saturated in CO2, a battery (extremely heavy) and a pump. So we managed to balance on the cubi with all of these…As bottles were emptying, I realized that half of the platform was with empty bottles and me just 50 kilos and the other part with the filled bottles and the battery…suddenly the filled bottles start drifting towards the water and the platform due to small currents almost turn. In milliseconds the battery was in the water, together with one filled 25 Liters bottle and Fred’s sun-glasses. We managed to lift the battery and Fred dried it with his T-shirt. He also jumped in the water to retrieve the filled bottle. I love it when troubleshooting stories have happy endings. We finished eventually the acidification of P6.