The presentation

2. The presentation What is a healthy lake? What are the major threats? What is eutrophization? What can be done?

3. Characteristics of a healthy lake Clear oxygenated water right to the bottom Few aquatic plants Lake trout and brook trout are typical

4. Major threats to the health of our lakes Acid rain

5. Major threats to the health of our lakes Acid rain Introduction of exotic species

6. Major threats to the health of our lakes Acid rain Introduction of exotic species Eutrophization

7. What is eutrophization? The accelerated development of plants in a lake, especially microscopic algae (plankton). Some speak of the aging of the lakes.

8. Impacts of eutrophization on use Water less clear Less oxygen in deeper parts More aquatic plants Increased risk of blue algae

9. Impacts of eutrophization on use Quality decline: Swimming Fishing Nautical sports Aesthetics = Less quality of life = Diminished tourist attraction = Lost $$$

10. The aging of the lake is a natural process, so why bother with it? Because man accelerates the process. Nature = several thousand years With human influence= several tens of years

11. What causes eutrophization? When water is enriched like in a garden to which fertilizer has been added One element in particular: phosphorus

12. Sources of phosphorus Natural Precipitations Forest run off, marshes, etc. Erosion Human activities Septic installations Deforestation, agriculture, roads, etc. Increased erosion Spreading of fertilizer, manure, etc.

13. A lake is its watershed All activities in the watershed of a lake results in increased levels of phosphorus and contributes to eutrophization. A lake reacts to the sum total of everything originating from its watershed

14. Eutrophization can be prevented A lake eliminates a portion of the phosphorus it receives Phosphorus levels less than the lake’s absorption capacity (its support capacity) are tolerable This support capacity can be calculated

15. Eutrophization is reversible Reduce phosphorus levels

16. Taking preventive action against eutrophization means reducing the amount of phosphorus entering the lakes Action can be: Individual Collective

17. Individually, this means reducing our ecological print Build and adequately maintain septic installations Reduce the use of phosphates (detergents, etc.) Reduce water consumption Protect the buffer area Do not fertilize; in agriculture, management of manure, livestock and fertilization plants Avoid erosion No needless deforestation Minimize surface sealing

18. Collectively Enforce existing regulations Land-use planning must be based on lake support capacity

19. To conclude We can protect the health of our lakes. It’s up to us to decide to do so Doing nothing or not doing enough also amounts to making a decision, because by so doing, we are agreeing to losing a major portion of our natural capital