Confidence votes 4.8K. The base meanining of un pigeonnier is a dovecote (a structure where doves, or similar birds, are bred or housed). But you will also find un pigeonnier used to mean a garret-flat, or any small flat near the top of a building (especially if it is a low-rent sort of place).
Duckweed creates an anaerobic environment. When it comes to wastewater lagoons, the lack of dissolved oxygen is bad. (Read our previous article, Troubleshooting Low Lagoon Dissolved Oxygen, for an in-depth look.) Duckweed is a DO killer, blocking the oxygen-transferring interface between the surface of the lagoon and the atmosphere.
Dissolved oxygen solubility is affected by water temperature, atmospheric pressure and salinity. Cold water can dissolve more oxygen than warm water. As the temperature goes up, water releases some of its oxygen into the air. Water also holds less dissolved oxygen at higher elevations because there is less pressure. Solubility of dissolved oxygen also decreases as salinity increases. Dissolved oxygen refers to the amount of oxygen contained in water. Oxygen has limited solubility in water usually ranging from 6-14 mg/L. Dissolved oxygen reflect an equilibrium between oxygen producing processes and oxygen consuming processes.