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.
Problems. Duckweed multiplies rapidly. It may spread from pond to pond on the feathers of waterfowl. When duckweed completely covers a pond it will block light from reaching other plants that live within the pond which in some cases leads to fish kills.Duckweed may be a symptom of other pond problems such as high nutrient levels.Duckweed thrives in nitrogen-rich environments.uckweed can be removed by raking or seining it from the pond's surface. Common duckweed is a very small light green free-floating, seed bearing plant. Duckweed has 1 to 3 leaves, or fronds, of 1/16 to 1/8 inch in length. A single root (or root-hair) protrudes from each frond.