1. 16/02/2005 Coste Sabrina Thessaloniki Charente basin polluted by Agriculture

2. Localization and presentation of the Charente basin Superficy 10 549 km2 Superficy 10 549 km2 Population 585 400 inhabitants Population 585 400 inhabitants Density 55,5 inhab/km² (40 à 100 inhab/km²) Density 55,5 inhab/km² (40 à 100 inhab/km²) In summer there are 117 445 inhabitants more In summer there are 117 445 inhabitants more divided in 4 under basin: divided in 4 under basin: – Charente upstream – Charente downstream – Boutonne – Tardoire Touvre

3. The 4 under basin

4. Agriculture :The fact – An excessive amount of fertilizer (nitrate and phosphate) To improve production of cereals ! To improve production of cereals ! – A lack of wetland and bank vegetation around the river,so phosphate with organic materials can leach directly into the river

5. What is happening ? A part of nitrate is taken up by plants A part of nitrate is taken up by plants Phosphate are attached to the soil, and this mineral must change before it can be incorporated by plants Phosphate are attached to the soil, and this mineral must change before it can be incorporated by plants – But more of this is staying in the river and causes damage in water

6. Eutrophication Main influences : Main influences : – Big amount of phosphate in the water – Photosynthesis – Staining water ( etiage when there is a prolonged hot summer and excessive removal of groundwater )

7. What are the main consequences? 1. Increasing of macrophytes, because zooplankton can not regulate this big development. 2. Decreasing of oxygen caused by : Development of unicellular algae Development of unicellular algae Increasing of bacteria activities which requires a lot of oxygen to decompose organic material Increasing of bacteria activities which requires a lot of oxygen to decompose organic material Anaerobic bacteria deplete oxygen levels so plants and animals disappear. Like it happened in the Charente basin (cyprinidae and rainbow trout) Anaerobic bacteria deplete oxygen levels so plants and animals disappear. Like it happened in the Charente basin (cyprinidae and rainbow trout)

8. 3. And the phenomenal of cyanobacteria which uses the atmosphere nitrogen and phosphate and develops very quickly Be careful it’s dangerous for human and phytoplankton because they produce toxic secretion (DDASS)

9. Hypothesis for restoration Moderate consumption of the groundwater by the population Moderate consumption of the groundwater by the population Cultivated land between green bands and streams Cultivated land between green bands and streams

10. REFERENCE http://www.enseeiht.fr/hmf/travaux/CD0102/travaux/optsee/bei/1/g 14/pa04.htm http://www.enseeiht.fr/hmf/travaux/CD0102/travaux/optsee/bei/1/g 14/pa04.htm http://www.enseeiht.fr/hmf/travaux/CD0102/travaux/optsee/bei/1/g 14/pa04.htm http://www.enseeiht.fr/hmf/travaux/CD0102/travaux/optsee/bei/1/g 14/pa04.htm