The ecosystem of the Claires (ground basins in marshland) is a confined milieu. It is influenced by weather conditions. Those conditions may have a great influence if the milieu is isolated. Those basins have as well a poor volume/surface ratio. It is then interesting to follow the physical and chemical parameters of the water:

The temperature of the water follows the temperature of the air, with weaker variation due to the heat inertia of the liquid. It influences the phytoplanktonic environment and other parameters. Saltiness is proportional to the water temperature.

The study of the water claire basin is important due to the important variation of the parameters. Oyster farmers take care about the temperature, the saltiness, and oxygen to avoid mortality. He takes in account the development of the blue Navicule, Haslea Ostrearia, for the oyster tartness.