Duckweed
Introduction
"One of the more important factors influencing the distribution of wetland plants, and aquatic plants in particular, is nutrient availability.[4] Duckweeds tend to be associated with fertile, even eutrophic conditions. They can be spread by waterfowl and small mammals, transported inadvertently on their feet and bodies,[5] as well as by moving water. In water bodies with constant currents or overflow, the plants are carried down the water channels and do not proliferate greatly. In some locations, a cyclical pattern driven by weather patterns exists in which the plants proliferate greatly during low water-flow periods, then are carried away as rainy periods ensue." - Wikipedia: Lemnoideae
Benefits of Duckweed
Climate Change
"Duckweed is being studied by researchers around the world as a possible source of clean energy. In the U.S., in addition to being the subject of study by the DOE, both Rutgers University and North Carolina State University have ongoing projects to determine whether duckweed might be a source of cost-effective, clean, renewable energy.[25][26] Duckweed is a good candidate as a biofuel because it grows rapidly, produces five to six times as much starch as corn per unit of area, and does not contribute to global warming.[27][28] The rapid nature of duckweed has shown that it can double biomass within four and a half days.[29][30][31] Duckweed removes carbon dioxide from the atmosphere, and it may have value for climate change mitigation.[32]" - Wikipedia: Lemnoideae
Duckweed may be appropriate for Paludiculture. - Potential Paludiculture Plants of The Holarctic
Biodiversity
The tiny plants provide cover for fry of many aquatic species." - Wikipedia: Lemnoideae
The following are just some species who benefit from duckweed:
Nutrition
Wildlife
"Duckweed is an important high-protein food source for waterfowl. ..." - Wikipedia: Lemnoideae
Humans
"Species of the genus Wolffia are traditionally used as human food in some of the Asian countries. Therefore, all 11 species of this genus, identified by molecular barcoding, were investigated for ingredients relevant to human nutrition. The total protein content varied between 20 and 30% of the freeze-dry weight, the starch content between 10 and 20%, the fat content between 1 and 5%, and the fiber content was ~25%. The essential amino acid content was higher or close to the requirements of preschool-aged children according to standards of the World Health Organization. The fat content was low, but the fraction of polyunsaturated fatty acids was above 60% of total fat and the content of n-3 polyunsaturated fatty acids was higher than that of n-6 polyunsaturated fatty acids in most species. The content of macro- and microelements (minerals) not only depended on the cultivation conditions but also on the genetic background of the species. This holds true also for the content of tocopherols, several carotenoids and phytosterols in different species and even intraspecific, clonal differences were detected in Wolffia globosa and Wolffia arrhiza. Thus, the selection of suitable clones for further applications is important. Due to the very fast growth and the highest yield in most of the nutrients, Wolffia microscopica has a high potential for practical applications in human nutrition." - Nutritional Value of the Duckweed Species of the Genus Wolffia (Lemnaceae) as Human Food
Shelter & Water Quality
"The plants are used as shelter by pond-water species such as bullfrogs and fish such as bluegills. They also provide shade and, although frequently confused with them, can reduce certain light-generated growths of photoautotrophic algae." - Wikipedia: Lemnoideae
Problems with Duckweed
Pollution & Invasiveness
"Despite some of these benefits, because duckweed thrives in high-nutrient wetland environments, the plants can be seen as a nuisance species when conditions favor excessive proliferation in environments that are traditionally low in nutrients or oligotrophic.
One example of this problem occurs within the Everglades, a mostly oligotrophic environment, when excess chemicals (that include fertilizers) are carried by storm runoff, or surface runoff, into its waterways.[11]
Urban runoff and agricultural pollution then begin to introduce increased levels of nutrients into the surrounding wetlands and waterways, which can cause a disruption to native ecology. These conditions allow for the invasion of a fast growing species such as duckweed to establish themselves, spread, and displace other native species such as sawgrass, and over time, result in widespread changes to the ecology of native sawgrass and slough habitats within the Everglades.[12]" - Wikipedia: Lemnoideae