CO2 uptake and O2 release by Posidonia oceanica with turbidity
Investigation of the experiment on CO2 absorption and O2 release by Posidonia oceanica
1. The questioning: "Is the photosynthesis of Posidonia a function of water turbidity?"
2. The hypothesis: When turbidity increases, photosynthesis decreases and Posidonia absorb less CO2
3. Materials: - 1 CO2 sensor - 1 arduino uno board - 1 grove shield (optional) - IDE arduino application on computer - 1 transparent tray - 1 bent tube - Scotch tape - 1 match - 1 screwdriver - Posidonia leaves - 1 plastic bag
4. Experiment:
- Create a program via the arduino IDE application on the computer
- Place the posidonia leaves in the tray and cover them with the plastic bag and close the bag tightly with the rubber band
- Make a hole in the bag with the screwdriver to pass the CO2 sensor connected to the arduino uno board (on which there is the grove shield) itself connected to the computer
- Make a second hole to pass the bent tube
- Surround the two holes with tape so that the whole thing remains airtight
- Trouble the water so that the turbidity increases
- Start blowing CO2 into the elbow tube while exhaling, then plug it with a finger
- The data captured by the sensor are displayed on the monitor of the arduino IDE
5. Results :
We entered our results in an Excel table to represent them in the form of a graph :
6. Interpretation of the results:
By comparing the results obtained when the water is turbid and therefore the turbidity is more important, we note that the rate of CO2 absorption by the posidonia over time decreases more slowly than when the water is clear. We can therefore conclude that the photosynthesis of Posidonia meadows is conditioned by the turbidity of the sea water, which can increase due to marine currents, extreme climatic events, the passage of boats, underwater work or aquaculture.