Duckweed can be used for bioremediation of waterways, meaning it can take up and absorb high amounts of water pollutants such as excess phosphorus and nitrogen, commonly discharged from agriculture runoff (Fertig, 2021).
It is very rich in nutrients and has been shown to be rather successful as an alternative feedstock for aquaculture, up to 30% can be substituted (Fasakin et al., 1999; in Olasunkanmi et al., 2021) instead of the over-exploited and ever increasingly expensive fishmeal.
Previous experiments have been done in the aquaponics greenhouse that can be seen here. They found that the duckweed used a lot of nutrients and that the bucket of choice might have been too small to properly start a good growth of duckweed. Hence our updated method seen below!
We added common duckweed found in the surrounding Amsterdam ponds to a large bucket with approximately 30L of aquaponics system water pumped from the sub-tank. We also set up a small pump stuck on the bottom of the bucket and hose that can be plugged in to aerate the still-water.
As you can see, the far left picture was on Monday (day 1), followed by Tuesday (day 2) and Wednesday (day 3). In only 3 days there has been a significant amount of growth!
Next steps are to feed parts to the fish and judge their reaction towards their new supplemented diet.
Fertig, W. (2021). Common duckweed (Lemma minor). U.S. Forest Service & United States Department of Agriculture. [online] Available at: www.fs.fed.us.
Olasunkanmi, J.B., Julius, O.T., Babalola, T.O., Jimoh, J.O. and Ariyomo, T.O. (2021). Alternative Feed Resources in Aquaculture: The Role of Underutilized Plants–A Review. In IOP Conference Series: Earth and Environmental Science (Vol. 655, No. 1, p. 012008). IOP Publishing.