What Is Common Duckweed And How Does It Affect Lakes?

Common Duckweed NatureSpot
Common Duckweed NatureSpot from www.naturespot.org.uk

Common duckweed, also known as Lemna minor, is a floating aquatic plant found throughout the world. It is one of the smallest and simplest of flowering plants, consisting of only a single leaf or frond with a small root. Duckweed is a fast-growing plant, capable of doubling its population size within two days. It usually grows in large colonies, which can cover the surface of ponds and lakes. Although it is beneficial in some ways, duckweed can also be very damaging to the ecosystem of a lake.

Benefits of Common Duckweed

Common duckweed provides many benefits to freshwater systems. It absorbs nutrients, such as nitrogen and phosphorus, from wastewater. This helps to reduce water pollution and can improve water quality. Duckweed also provides food and habitat for aquatic organisms, such as fish, frogs, and insects. In addition, it produces oxygen through photosynthesis, which helps to maintain a healthy balance of oxygen in the water.

Drawbacks of Common Duckweed

Although duckweed can be beneficial in some ways, it can also cause significant problems in lakes and ponds. It can quickly spread and form dense mats that cover the water’s surface, blocking sunlight and limiting the growth of other aquatic plants. This can lead to a decrease in oxygen levels, as well as the death of fish and other aquatic life. In addition, duckweed can clog irrigation systems, dams, and other structures, causing economic damage.

Control of Common Duckweed

Controlling common duckweed requires a combination of methods, including physical, chemical, and biological control. Physical removal is the most effective and least expensive way to reduce duckweed populations. This can be done by manually removing the plant from the water or by using mechanical harvesting equipment. Chemical control involves the use of herbicides, but this is not recommended due to the potential for water contamination.

Biological control involves the introduction of natural predators, such as grass carp, which feed on duckweed. This method is not recommended in areas where native fish populations are already threatened. In addition, this method can also cause water contamination if not done properly. Overall, controlling common duckweed requires careful consideration of the potential benefits and drawbacks of each method.


Common duckweed is a fast-growing aquatic plant that can provide many benefits to freshwater systems, such as nutrient absorption, food and habitat for aquatic organisms, and oxygen production. However, it can also cause significant problems if it is not controlled properly. Physical removal is the most effective and least expensive method of controlling duckweed, but chemical and biological control methods may also be used in certain situations. Ultimately, the best way to control duckweed is to understand its potential benefits and drawbacks and use the appropriate control methods.

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