MESO-Plastic experiment @Cretacosmos, Greece

I’m Chiara, I’m 22 years old and I study Biological Sciences in Florence, the city where I live. I’ve arrived at the HCMR of Gournes, Heraklion, for my traineeship with Luisa, who decided to set up her experiment on microplastics in sea water here in Crete. Everybody knows that seas and oceans are full of microplastics, but what is their effect on marine ecosystems? This is what we are trying to discover here together with a great team of HCMR researchers and it’s my task trying to tell you what’s happening every day.

The working team consists of:

Luisa: Postdoctoral Fellow at University of Siena and principal investigator of the project

Manolis: Associate Researcher at HCMR of Heraklion

Vivi: Associate Researcher at HCMR of Heraklion

Ioanna: Postdoctoral Fellow at HCMR of Heraklion

Eleni: PhD student at HCMR of Athens

Iordanis: PhD student at NOC, Southampton, UK

Anastasia I: PhD student at HCMR of Heraklion

Iulia: PhD student at HCMR of Heraklion

Kiki: research technician at HCMR of Heraklion

Santi: research assistant at HCMR of Heraklion

Eleni: research technician at HCMR of Heraklion

Hionati: research technician

Steven: Associate Professor at University of Siena, Italy

Anastasia II: Master student at University of Heraklion

Chiara: Bachelor student at University of Florence, Italy

Arturo: Bachelor student at University of Edinburgh, Scotland


23rd of May

The adventure has started! Today was a very hard day at HCMR but really important for our experiment: we prepared and cleaned all the equipment for the experiment with diluted HCl and water! It seems easy, but to wash each tank at least 3 people were needed!
And in the afternoon we placed  the very protagonists of this experiment: mesocosms! They are not so little, they seem like big baskets containing around 3000 litres… of sea water! and 3 of them, microplastics that we will add! Everything is going good at HCMR, even if we had some last doubts before the very beginning and some little problems that were easily solved. Besides such things are just a routine for scientists! All the researchers are very gentle and nice with us, we had so much fun during the whole day in the lab! And we are also trying to learn some Greek words…
Meanwhile we enjoy the Greek cuisine!




Day 0 – 26/05

The experiment just started! Day 0, we started sampling the water for the analysis of the nutrients and after that, at 8.00 am with the sampling of the sea surface microlayer… I thought we would have made a simple sampling with a syringe or something similar but… we used a glass plate and a scrubber! How does it work? We have to dip the glass plate in the water up to a line ( 30 cm below the surface) and remove it slowly, so that a film of organic material sticks to the plate. Then we have to wait for a moment to let the biggest drops fall down and try to collect as many drops of water attached to the glass plate as possible and transfer it to a bottle! It is not so easy as it could seem, because we had to collect almost 300 ml and we did 70 dips of the glass plate for each mesocosm! The first sampling was very exhausting… But it was just the beginning! Then we collected the bulk water from each mesocosm, almost 5 liters, enough for all the analysis… and what about the microplastics? In the afternoon, we started the real treatment: Luisa added the same amount of polystyrene microplastic particles in 3 of the 6 mesocosms!! Almost 1 300 000 pieces of 30 µm for each one! We’ll see their effects in the mesocosms in the next days.

For the nutrients, P04 and NH4 values aren’t very high, but they’re enough for a real situation and we decided we won’t add nutrients and see the natural development of the phytoplankton bloom…Let’s get the experiment started!


Day 1 – 27/05

We arrived very early in the morning to check the temperature and the oxygen in each mesocosm and to sample enough water for the analysis of the CO2… We’ll send the bottle to Germany, to the GEOMAR in Kiel, for the analysis!

Eleni- after nutrients analysis

After the sampling for the nutrient analysis by Eleni and Hionati , we started with the sampling of the sea surface microlayer again, but after the first time everything seems definitely easier, and even funny! We tried to sample fast, because the weather didn’t help us… it sounds impossible for Greek people in Crete to see rain in May, but after our sampling a storm started! However, we did it! And it already seems that the glass plates of the mesocosms treated with microplastics have more sticky substances, because we collect them easier…we’ll see! For the bulk water sampling was easier. We collected 5 litres as usual  with a tube for chlorpphyll, POC (particulate organic carbon), and for microplastics abundance and metals. In the evening Arturo has arrived from Edinburgh to help us with the sampling! Welcome Arturo, definitely a hand is needed!


Day 2 – 28/05

It is Sunday today, but mesocosms and plankton don’t go on holiday and we arrived as usual at the HCMR early in the morning! But no surface water sampling, only bulk! We started in the morning with the usual analysis, but with less hurry… Luisa had the time to analyze the filters she had prepared the previous day colored by Alcian Blue for carbohydrates and Coomassie Blue for proteins… We managed to already see  a difference between the substances in the sea surface water and the bulk. The surface is full of molecules and even some strange organisms! Eleni and Ioanna are involved in the filtration of the metals, almost 300 ml and all the falcons collected will be analyzed in the HCMR of Athens by Eleni.

After the day of sampling, we went to the bus station to pick up Steven! He comes from Siena and we were looking forward to have him here as well!


Day 3 – 29/05

It’s Monday today and at the institute there are many researchers working. And for us, sea surface microlayer (SML) sampling again! The SML team consists of Luisa, Eleni, Ioanna, Chiara (myself) and Arturo and we are pretty good by now! Only 60 dips are enough to fill the bottle up to the correct volume! After the sampling we share the volume collected: Ioanna and Eleni need 100 ml for the

filtration of the metals, about 30 ml for the filtration of the CDOM by myself, 10 ml for the analysis by flow cytometry by Anastasia and Anastasia II (the same name, the same beginning of the surname… and the same passion!). The last milliliters are for Luisa who collects the filters painted by the stains in blue to check them at the microscope. For the bulk, today it’s up to Manolis and Anastasia and as soon as the water is collected, Santi takes about 2,5 liters for the filtration of the chlorophyll and particulate organic carbon. It’s very hot today, the rain has gone and also the summer is coming! But we start organizing and taking confidence with the roles in the experiment, so everything seems easier and the team gets on very well!


Day 4 – 30/05

After the usual sampling of the bulk water we had a meeting all together to discuss about how the experiment is going on. Manolis showed the graphs with the latest concentration of the nutrients and it was clear that the numbers weren’t so high, even if we could see a normal, but low, distribution of the nutrients… We decided to go on with the values we had, without adding anything.  We wanted to see natural conditions. Anastasia showed us the graphs for the growth of bacteria: there’s a peak of  bacteria in day 3 and then, probably a drop of heterotrophic ones as the nutrients decrease. Being in a meeting with so many researchers seems like a film scene where everyone says his opinion and adds something to the discussion according to their knowledge and studies. It’s very challenging!

The twilight in Gournes, after the whole day working


Day 5 – 31/05

The whole team in Archanes

Half way through the experiment… how fast days are passing by! This morning the glass plates were waiting for us! But 55 dips were enough today! We get more and more water with less dips now… there are lots of sticky “things” in the sea surface! And Luisa can confirm it also by the analysis with the microscope of the filters she coloured with the blue stains… today she also found some strange organisms just in the SML, not in the bulk water. What could they be? Vivi came to check them but they are so strange, the research starts and maybe tomorrow we’ll have the answer. In the meanwhile… this evening we’ll have a dinner all together in such a nice and traditional tavern in Archanes, a village close to Heraklion… I’m looking forward it!:)                   


Day 6 – 01/06

The dinner last night was great, we all love Cretan food (and wine ;P). We went home pretty late, but it’s a more calm day today, with the bulk sampling made by Anastasia II and Manolis and all the other analysis. About the organisms in the filters of the SML, Vivi discovered that they are a species of Ciliate, common for coastal water and seems that they are blooming now, and we only see the in the very surface! How strange.. Maybe it could be an interesting discovery!


Day 7 – 02/06

Last day for Steven! After the SML sampling under a very hot sun,we had a meeting all together… the thoughts of all the team seem positive for the future results. After a picture all together in front of the mesocosms, we say goodbye to Steven with an ice-cream at the bar of the aquarium (Cretaquarium)… Does someone else want to be greeted? 😛

Cretaquarium and HCMR behind


Day 8 – 03/06

Today we are only Luisa, Arturo, Anastasia II, Santi and me at the institute. It is Saturday and we’d love to go the the beach, but mesocosms are waiting for us, so, the beach will wait! Anastasia II is ready to make

Santi working in his lab

all the chlorophyll analysis after the filtration of Santi and to use the flow cytometer alone… thanks to all the teachings of Anastasia I who has just take one day off after all these days working. The values of the chlorophyll are very low but it’s the normal decrease towards the depletion of the nutrients and in perfect time with the end of the experiment…


Day 9 – 04/06

This morning was very very hot and the SML sampling was very  challenging! It’s Sunday, we were very few at the institute and there was a strange silence inside! However we did all the analysis and we managed to finish not so late just in time to have a bath! The experiment is going to end soon, as nutrients are low and everything is going to come back to normality… It was such a beautiful adventure! But maybe it’s better to leave the comment for tomorrow, after the last SML sampling!


Day 10 – 05/06

Last day of sampling! Last cleaning of  the equipment, last filtration of microplastics, last analysis of chlorophyll and the metals, and flow cytometer… Last goodbye to all the funnels and all the glass plates… Well, maybe we won’t miss them so much! But all the experiment was such an emotion to me, and very interesting! The balance is very positive in every case… I learnt many techniques and many information useful for my biological studies and I known very nice people here… I feel very lucky to be part of this team! Now Luisa can finally relax and enjoy after the whole work! She has just to gather all the results and make a complete summary of the experiment… but we will see in the next months! Thanks to everybody, great job 🙂

Luisa, Ioanna, Eleni and me in the lab for the last filtrations


Day 11 – 06/06

Ooops…I said last sampling was yesterday! Well, we had another one today. Just for the bulk, easy one, CO2, nutrients, chlorophyll, POC, flow cytometry…we had a final meeting all together, to discuss latest results, follow up, and have some cake and wine together and then we went to visit the Cretaquarium! That was great! Great end of the experiment! We said goodbye to Eleni who was going back to Athens – by ferry, overnight! We will miss her.

We went back home, walking by the sea-side. We cooked and went to bed and maybe, for the first time after two weeks, we really slept like stones! In the next days we’ll be around at the institute.. packing, some office work, checking samples.. then a few days of holidays in Crete and back to Italy.

With the hope to come back here one day, maybe for another mesocosms experiment…That has been really an amazing experience!