Fishing for the Future: How Aquaponics at UC is Helping Revolutionize Farming

In a small, noisy laboratory in Crosley Tower, chemists from the University of Cincinnati are revolutionizing the way we think about food. There, draining systems whir and tubes pump water back and forth. 

It’s here that research assistant professor Julio Alberto Landero and his team of two doctoral students and two undergraduates in the Department of Chemistry are experimenting with aquaponics, a self-sustainable agriculture method in which fish and plants are grown together in one integrated, symbiotic system. The waste produced by the farmed fish—in this case all-male tilapia—supplies organic nutrients for the plants, which in turn use their roots to filter the water the fish live in forming a closed system. This technology is growing at a fast rate in the United States, yet basic knowledge on low-level contaminants accumulation within the system has not been properly studied. 

For more than 10 weeks per experiment, Landero has been supplementing the system with various amounts of selenium, a known antioxidant essential at low doses that can potentially be toxic at high concentrations and a currently unregulated additive in fish feed in the U.S. By analyzing different selenium levels, the team is trying to determine the most efficient way to grow both fish and plants under closed loop water conditions. So far, lower selenium levels create greater yields. 

“The purpose of these experiments is to optimize aquaponics,” Landero says. “This is the future of making food. You don’t waste water, you can do it indoors and you can do it vertically.” 

In the lab, a group of 10-gallon tanks teem with 35 Nile tilapia each—a tenfold increase in density when compared to reports from other labs. The improved concentration is maintainable by reducing selenium levels to decrease its toxicity. 

 Although the first aquaponic technique can be sourced back to the Aztecs, who raised flora on floating rafts of land (called chinampas) in ponds, recirculating aquaculture systems as we know them today were developed within the last 35 years. As modern agriculture continues to focus more on urban spaces and environmentally green processes, aquaponics holds exciting potential that Landero hopes to maximize. 

Most aquaponics systems can only harvest low-protein crops like lettuce and basil, but Landero wants to change that. “If you want to grow fruits and other higher protein vegetables, you need a more concentrated system with more fish producing more waste,” he says. 

The optimization of fish feed compositions to fulfil the requirements of this unconventional farming method and the levels of selenium supplementation in the vegetable and animal portions will be additional scientific products obtained from this research.

Landero is also experimenting with selenium levels in a second aquaponics system in Rieveschl Hall’s rooftop greenhouse, but says that the fickle Cincinnati weather—daytime highs can dip to dramatic lows by nightfall—limits that location’s sustainability potential. 

Landero’s project is the first time anyone has analyzed the selenium levels of an aquaponics system. By maintaining low levels of the element in the feed, the fish are able to cultivate protein-high pinto beans. The plants are growing quickly, and soon they’ll start using manmade materials in the lab, like light fixtures, as trellises to climb toward the ceiling.