Practical Information

Psychochemistry

• A good estimate of the average summer transparency of the water was obtained by 8 measurements of the depth of the Secchi disk. This transparency of 2.4 meters characterizes turbid water. This variable places the trophic state of the lake in the meso-eutrophic transition zone.
  

• The average concentration of total trace phosphorus measured is 14 µg/l, indicating that the water is enriched with this nutrient. This variable places the trophic state of the lake in the mesotrophic class.

• The average concentration of chlorophyll a is 13 µg/l, revealing an environment with a very high biomass of suspended microscopic algae. This variable places the trophic state of the lake in the eutrophic class.

• The average concentration of dissolved organic carbon is 5.8 mg/l, indicating that the water is colored. The color therefore affects the transparency of the water.

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Trophic State

• The physicochemical variables measured in one of the deep-water zones of Lake Magnan give conflicting signals, but its trophic state is likely in the meso-eutrophic transition zone. The summary of the results from the years of monitoring is illustrated in the multi-year report.

(source :  Au-menu-un-regime-faible-en-azote-et-phosphore)

• Based on the results obtained, Lake Magnan is at an advanced intermediate stage of eutrophication. To slow down this process, the MELCCFP recommends adopting measures to limit the input of nutrients from human activities. This could prevent further degradation of the lake and additional loss of its uses.