PROJET « GRAINE DE REPORTERS » RÉALISÉ PAR LES ÉLÈVES DE LA TERMINALE DNL/SVT
Les élèves de DNL SVT terminale ont participé a un jeu concours réalisé par la fondation Tara Océan .
Pour en savoir plus sur TARA:https://oceans.taraexpeditions.org/m/qui-est-tara/)
Productions des élèves:
Et également sur la page de votre académie depuis ce lien :
Mme CASTRY-ELYSER
Professeure de SVT et de DNL SVT
School years 2016-2018
The automatic watering can
The last year the students decided to realize an automatic watering can for houseplants owners who need to keep their plants safe when they go on holiday.
The students studied the needs of the most common houseplants. They imagined the design, the material, the sensors and the program for their watering can.
They decided to program it on a Raspberry Pi motherboard, a tiny and affordable computer. We wish to thank Mr Grandjean, a engineering sciences teacher who helped us for the understanding of Raspberry Pi.
The design phase has been achieved but the students did not write the program this year.
Miss URITY O, biology and geology teacher for the European Class.
Design concept made by Lindsey Desirliste
School year: 2018-2019
Biodiversity of the mangrove of Genipa Bay
Lenticels on the red mangrove tree roots.
Source : www2.palomar.edu
Finally, between the mangrove swamp and the ground, we find the white mangrove trees (Avicennia germinans, Verbenacea) and the grey mangrove trees (Conocarpus erectus, Combretaceae). During our visit we didn’t see these two last species.
The mangrove swamp establishes the completed refuge for numerous species. It is an area of breeding, passage for migratory birds and food.
In the mangrove swamp itself we saw different species of animals and plants:
Aratus pisonii a crab specie which lives on the stilt-roots, photo by Christale Crouard
Green Heron , Butorides virescens also called “kayali” in creole speaking language
Ardea alba ,the Great Heron a migratory bird
An unknown spider specie, photo by Crouard Christale
Source: https://pixabay.com
Mongoose specie (Viverridaea)
Common moorhen (Gallinula chloropus, Rallideae)
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Water hyacinth (Eichhornia crassipens, Pontederiaceae) an invasive plant which colonized the “Rivière-Salée”.
Source: https://pixabay.com
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Author : CROUARD Christale
Lay-out : Loustalet Clara, Boniteau Guillaume, Miss URITY
Appreciations to: Nicolas Lecerf for his help
Correction : Miss URITY and Miss Marie-Luce
Physico-chemical measurements in the mangrove
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Some students have made measurements in the sea water so we were able to study some physico-chemicals characteristics of the mangrove.
-Water conductivity: It is defined as the ability of a substance to conduct electricity. It can give an idea of the amount of ions found in the liquid.
Stephan during the recording of water conductivity, photo by M.KNIFIC
pH:
The pH is a measure of hydrogen ions concentration. It allows to determine the acidity and the alkalinity of a solution. It’s expressed as a number on a scale on which a value of 7 represents neutrality and lower numbers indicate increasing acidity and higher numbers increasing alkalinity.
Lucas doing a pH measurement, photo by K.Morin
Temperature
A measure of the warmth or coldness of an object or substance with reference to some standard value. The temperature of two systems is the same when the systems are in thermal equilibrium
Guillaume recording the temperature, photo by K .Morin
Water samples
We took several samples of water in order to analyze them in class and determine the salinity in different sites of the Genipa Bay and the Rivière-Salée.
Authors : Knific Matteo and Morin Kelian
Lay-out : Loustalet Clara, Boniteau Guillaume, Miss Urity
Correction : Miss Urity and Miss Marie-Luce
Determining the salinity of the water samples
We have taken samples of water at different places in the mangrove. Then we brought them back to school where we realized salinity tests with each sample.
The salinity is the quantity of dissolved salt in the water. We can find different ions in the water : sodium, chloride, magnesium, sulfate, potassium, nitrate and sodium bicarbonate. The most important ions are chloride and sodium; the others are in negligible amounts so the value of salinity is not so far different from the value of the concentration of the chloride and sodium ions.
We used titration with silver nitrate to determine the concentration of chloride ions in order to get the chlorinity of our samples.
Hands-on in biology class.
Source: France-antilles
We have considered that the chlorinity was close to the value of the salinity as that ion and the sodium are the major ions in concentration in the sea water. By the way the concentration of sodium is equal to the concentration of chlorine.
So we didn’t take into account the other ions in our experiment.
We measure a solution of chloride ions Cl- of molar concentration C1 by using a solution of ions Ag + of molar concentration C2 known, in the presence of a solution of neutral chromate of potassium serving as indicator of the end of reaction.
The steps were :
- Take 5 ml of your sample and put it into a beaker.
- Fill the buret with the silver nitrate solution. (use the instructions for use)
- If the buret is ready (no air bubbles, no leaks) : take an initial volume reading.
- Deliver the silver nitrate solution until the appearance of the red color.
- At that point take the volume of delivered silver nitrate.
| Number of the sample | Location : GPS point | V(Ag+) E (ml) | C (Cl-) mol.l-1 | SALINITY (g.l-1) |
| 1 | Latitude : 14° 32 .265’N
Longitude : 61°0 .743’W Pottery mangrove
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31 | 0,62 | 22,01 |
| 2 | Latitude : 14°33.072N
Longitude 60°59.888 W Rivière-Salée Entrance of the mangrove |
25 | 0,5 | 17,75 |
| 3 | Latitude : 14°32.795N
Longitude : 60°59.525W Rivière-Salée
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1,2 | 0,024 | 0,852 |
| 4 | Latitude : 14°32.729 N
Longitude : 60°59.502 W Rivière-Salée 30 meters before the RN5 |
0,2 | 0,04 | 1,42 |
| 5 | Latitude : 14°33.017N
Longitude 61°0.220W Open ocean, close to the « Petit Piton » Islet
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40 | 0,8 | 28,4 |
Table with the results of our experiment
To conclude we can say that the salinity changed according to the places where the sample had been taken. The salinity increases when we go from the Riviere-Salée to the « Pottery ». We can deduce that the Rivière-Salée is composed of fresh water and that the mangrove has brackish water with a salinity situated between the salinity of seawater and fresh water (Samples number 1 and 2).
We will take other samples in Lousiana (bayou and swamp) in order to compare the salinity of theses ecosystems with the salinity of the mangrove.
Authors : Lacroix Elisa, Miss Urity
Correction : Miss Urity and Miss Marie-Luce
Natural and human threats on the mangrove
Mangroves are one of the most productive and richest ecosystems in the world, but also the most endangered.
In fact, they are threatened by several human activities such as :
- Urbanism and port infrastructures: the construction of roads and infrastructures is responsible for deforestation and cause the disappearance of mangroves.
- Coastal erosion : It is the gradual destruction and removal of rock or soil in a particular area. It can be enhanced by deforestation and storm waves.
- Overexploitation of wildlife causes a reduction in the amount of young fishes that grow in the mangrove, this would cause an imbalance in the food chain of the mangrove.
- Industrial and domestic pollution such as wastes and wastewater discharged into nearby mangrove ecosystems such as rivers, marshes and rivers. They can eventually reach the mangrove due to currents and tides. Rejected directly into the mangroves, they induce as many problems and bad odors, degradation of water quality by wastewater loaded with various chemicals from domestic and industrial activities
- Climate change : It is now a certainty that storm events are more frequent on a global scale, as the level of water and ocean surface temperature increase due to global climate change.The impact of these events on marine levels could threaten the long-term survival of mangroves.
Conceptual framework : Principal impacting factors of climate change and how they are likely to negatively influence mangrove communities
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| Source : http://onlinelibrary.wiley.com |
Authors : Solitude Valentin,
Lay-out : Loustalet Clara, Boniteau Guillaume, Miss Urity
Correction : Miss Urity, Miss Marie-Luce
Click on the video above to see the bayou
During our trip in Louisiana we visited the swamp and the bayou at Jean Lafitte National Historical park and Preserve, Lafayette.
Due to the presence of Alligators, the guide Jason, tooks the samples of water for us.
Then, during a biology class session in St Martin Episcopal Church, we used a refractometer to determine the salinity of the water of these 3 ecosystems : the canal, the swamp and the bayou.
The results are presented in the following table.
| Samples | GPS points | Salinity g.l-1 | pH |
Sample 1 : canal |
Latitude : 29° 46 .973N
Longitude : 90°5.663 W |
0 |
6,12 |
Sample 2 : swamp  |
Latitude : 29°47.079N
Longitude 90°5.174W
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0 |
6,20 |
Sample 3 : bayou  |
Latitude :
29°47.052N Longitude : 90°4.680W |
0 |
6,31 |
| Reference test:
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35 |
5,46 |
To conclude, the bayou and the swamp are composed of fresh water. Even if they share some physico-chemical characteristics and some living beings adaptations with the mangrove the salinity is very different.
Authors: Joseph-Julien Anaëlle, Crouard Christale, Urity Olivia
Video editing : Crouard Christale
Appreciation to : Perro Philippe for his help, Miss Stacy Richards from St Martin Episcopal School from Metairie, Louisiana
Biodiversity of the wetlands of Louisiana
The tree species
The Bold Cypress (Taxodium destichum) and the Spanish Moss ( Tillandsia usneoides)
The Tillandsia usneoides or Spanish moss (mousse espagnole ) was used by the doctors to sew up people.
The Red Maple (Acer rubrum)
The American Dwarf Palm (Chamaeops humilis)
The Water Hyacinth (Ecchornia crassipens)
The hand prosthesis
During the second part of the year the students decided to build a hand prosthesis for our lab skeleton named Alphonse.
First of all the students had to understand the biological functioning of a hand. So we studied the mecanisms which allow the brain, nerves, muscles and tendons to move the different fngers of the hand.
Then we worked on the design and the material that we were going to use in order to realize the prosthesis.
Then we worked on the design and the material that we were going to use in order to realize the prosthesis. We chose to build it with the 3D printer located in the engineering lab of the high school.
Mr Perro, an engineering sciences teacher helped us for the choice of the program and the motherboard used to move the prosthesis. So it has been programmed with the Arduino software.
The Following video shows the glove , cables, motor and sensors used to move the 3D printed hand.
Watch and enjoy!
Miss URITY , Biology and Geology teacher for the European Class
The hand prosthesis concept made by Naullet Arthur, Annette Léo and Crouard Chrystale