National Geographic : 2019 Aug
Fish food Nitrobacter (bacteria) Nitrosomonas (bacteria) Seeds LED lamp Peat, foam, or other growing material Seedling Nitrite (toxic) SUMP PUMP REARING TANK FILTER TANKS AIR PUMP GROW BED Polystyrene raft Roots Bibb lettuce Filters 100 ft COMMERCIAL SYSTEM Rearing tanks Grow beds Tilapia (Oreochromis aureus) Nitrate (nutrient) Ammonium (toxic) Nitrates DECODER BY MONICA SERRANO ALEXANDER STEGMAIER. ART: DAVID KILLPACK. SOURCES: DONALD BAILEY, UNIVERSITY OF THE VIRGIN ISLANDS; HYE-JI KIM, PURDUE UNIVERSITY Two to three gallons of water can support as much as one square foot of growing space. LEDs that glow with a purple mix of red and blue promote growth and can provide more hours of light than sunlight. Leafy crops are easiest to grow aquaponically and include lettuce, herbs such as basil and mint, and medical cannabis. Purified water is recirculated to the rearing tank. Seedlings are moved from nurseries to rafts atop soil-free grow beds up to 18 inches deep. Plants immersed in flowing, nutrient-rich water can grow twice as fast as land crops. About 98 percent of water, now free of toxic ammonia, circulates back to fish-rearing tanks. 4 5 6 SMALL-FOOTPRINT FARMING Commercial aquaponic systems can yield up to 12 times as much produce per square foot as crops grown in soil—a boon to areas with limited freshwater and arable land. Current research focuses on reducing energy use and incorporating automation.