A reef in the library...

At the Lycée Montesquieu, in Le Plessis-Robinson, a small group of pupils puts in extra hours at the library twice a week. Here they have a sea water aquarium with coral, exotic fish and invertebrates. The aim of the project is to recreate a marine habitat, study underwater life and win an award in the next “Faites de la science” context!

In pride of place opposite the entrance, amongst the computers and the shelves of books, this tank containing 400 litres of sea water is a real masterpiece in the library of the Lycée Montesquieu (Le Plessis-Robinson, a suburb about 6 km from Paris). While Maxime Duez, the science teacher and amateur aquarist responsible for setting up the project, talks about the main idea behind the project, some upper sixth form science pupils are busy taking water samples from the tank. Two clown fish, nicknamed “Nemo”, are watching them from their hiding place behind the rocks topped with coral.

Next to the aquarium, a year 11 pupil is doing some research on the Internet in order to complete some slips. Charlotte tells me about the little underwater inhabitants she is finding out about: “Paracanthurus hepatus, Zebrasoma flavescens.” When she realises I look a bit taken aback, she agrees to stop talking in Latin: “A blue tang we have named Doris, a yellow tang called Banjo, the two Nemos, some dascyllus fish, two goby fish one of which is a fire goby, some very shy shrimps, two starfish buried in the coral sand imported from Hawaii, a colony of snails which have just reproduced very successfully and a few hermit crabs...” As for the corals, this time there is no escaping the Latin names: Acropora, Montipora, Euphylia, Stylophora and Seriatopora are colourful hard corals (yellow, purple, green, brown and even fluorescent pink), while the soft corals include a xenia, a sarcophyton and a sea fan.

In order to live in harmony, this little underwater world needs to be looked after with great care by the pupils who volunteered. The lighting, the water temperature (between 24 and 27 °C depending on the season), its precise composition, movement, filtration, density, evaporation… are just some of the many parameters that have to be meticulously measured and controlled. Therefore, every week the pupils make a series of measurements, take samples, carry out tests and add the chemicals that are necessary to maintain life, such as calcium, carbonates, iodine, etc. The food is dispensed automatically, leaving the young aquarists free to concentrate on the chemical properties of the actual environment. They have quickly taken over the project, carrying out all the analyses, calculations, measurements and experiments themselves, allowing the teachers to simply check any results the pupils are not sure about. Christophe, who is carefully adding liquid calcium (CaCl2) to the water in the tank, explains “you have to pour the solution in very slowly, so that it spreads evenly through the aquarium. The coral needs calcium to grow.”

The ten or so corals in the tank seem to appreciate their diet. Indeed, most of them were introduced at the beginning of the 2007 school year (the first one was used to test the equipment from June onwards, since corals and other invertebrates - such as anemones and triacnid clams - are regularly added to the aquarium) when they were only one or two centimetres tall. And now these strange animals, that look just like plants or rocks, have all practically doubled or even tripled in size! One should mention that there are no predatory animals in the biotope our pupils have created. They all live in peace and each one contributes by playing a specific role. The fish excrement feeds the corals, the starfish and hermit crabs move the sand which filters the water, and the snails tirelessly clean the glass and eat the algae!

But it is time to introduce a new coral now. Yassine, who has already washed his hands carefully, manipulates a ball of epoxy glue (a resin which is a strong adhesive) which will be used to fix the coral, while the other pupils and the teacher examine the aquarium to find the right spot. This type of hard coral needs a lot of light (so it should not be placed too deep) and enough space to get its room to grow. Eventually they select a suitable rock. Yassine stands on a chair, fixes the end of the coral to the resin and plunges his arm into the aquarium. It’s a dangerous manoeuvre: he has to be careful not to cause any damage or injury to the other inhabitants while he is installing the new arrival. Also, once it’s submerged the epoxy resin does not stick any better than a piece of play dough, so it has to be firmly stuck to the rock before it starts to harden and fixes the coral, which will end up covering it completely. After a bit of trial and error, the cutting of euphylia is finally planted in its new environment….left to prosper under the watchful eyes of the Nemo and the Aquarist club of the Lycée Montesquieu!

When it is time for the "Faites de la Science" competition, these high school students will present their work jointly with the students from an engineering school, Ecole Centrale Paris, who have developed a prototype which automatically measures the chemical parameters of the aquarium and adds calcium and carbonates in standard doses calculated by the pupils in the workshop. A system that will allow them to finally go on holiday far from their reef!

Key facts

The title of this operation, Faites de la science, is a word play between two homonyms: "fête" (party) and "faites" (make).

Practical information on the competition:

  • Objective: Promoting science to secondary school pupils
  • Organiser: Science departments of French universities
  • Partners: French Ministry of Education, the French Academy of Sciences, major research organizations.

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