Salt-loving plants clean fish farm water and grow food too
Bell A, Ergas SJ, Main K, Rhody N, Guttman L
Food Forest
If you've ever grown sea purslane or other edible succulents in a coastal garden, this shows the same salt-tolerant plant can double as a natural water filter, pulling waste out of fish tank water while producing a harvestable, omega-3-rich green.
Scientists raising red drum fish in tanks tested three ways to keep the water clean: using algae mats, mechanical filters, or edible sea purslane plants alongside the algae. The sea purslane setup kept ammonia and nitrogen in check just as well as the mechanical option, but used less energy and grew over a gram of edible, salty greens per plant per day. The algae itself turned out to be a hidden bonus too, pumping oxygen into the water and containing healthy omega-3 fats.
Key Findings
Periphyton (algae biofilm) added an average of +3.95 mg/L/day of dissolved oxygen to the water, cutting energy costs, and contained 4.55% lipid by dry weight including omega-3 fatty acids.
Sea purslane grown alongside periphyton filters achieved efficient growth rates of about 1.04 grams per plant per day while helping treat wastewater.
Moving bed biofilm reactors removed ammonia fastest but required more energy for oxygenation, while periphyton-only systems best stabilized alkalinity and pH.
chevron_right Technical Summary
Researchers tested three biofilter setups in a fish-farming system growing red drum, and found that combining edible sea purslane with algae-based filters kept water clean while producing a harvestable, salt-tolerant crop as a bonus.
Abstract Preview
Original paper
Performance of moving bed biofilm, periphyton, and halophyte biofilters in marine multi-trophic aquaculture systems.
Combining multi-trophic recirculating aquaculture system (MT-RAS) biofilter types leverages the strengths of different ecological biomes, benefits water treatment, resource recovery, economics, and...
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