By Paul Hollis, Auburn University College of Agriculture
It looks like a natural fit: a sustainable system that produces fresh vegetables and fish located in food deserts with marginalized populations.
And, while there has been an explosion of interest in these systems, there are significant technological and social barriers hindering its adoption. Overcoming these barriers is the goal of a research project being conducted at Sullivan Foundation partner school Auburn University and led by Brendan Higgins, assistant professor in the College of Agriculture’s Department of Biosystems Engineering.
“At its best, aquaponics allows local people to produce their own fresh fish and produce in a sustainable manner: The wastewater from the fish is used to provide water and fertilizer to the plants,” Higgins said. “However, the development of this fusion of aquaculture with hydroponic vegetable production in food deserts doesn’t come without barriers.”
These barriers include: 1) systems that are prone to instability without advanced technical knowledge; 2) fish and produce quality that do not meet consumer quality demands (e.g., muddy fish flavor); and 3) food safety issues, given that pathogens in the fish wastewater can contaminate the vegetables.
Until these issues are addressed, Higgins said, aquaponic systems—and their nutritional and environmental benefits—will remain “out of reach for marginalized populations.”
The objective of the research project—which is working with a $575,730 grant from the National Science Foundation—is to improve understanding of how aquaponics design decisions (e.g., integrating algae into biofloc, coupled vs. decoupled systems) impact microbial stability, pathogen dynamics and product quality.
The project will get pretty technical. “Our central hypothesis is that algal biofloc and decoupled systems will exceed the performance metrics of bacteria-centric biofloc and coupled systems [85% of current systems] in terms of system stability and ease of operation, nutritional and flavor profiles, and pathogen management when placed in the hands of novice users,” Higgins said.
The project will allow researchers to rigorously test integrating algal-biofloc and decoupled plant production into small-scale aquaponics systems, both independently and in combination.
So what exactly is algal biofloc? As Higgins explained, it’s a mixture of algae and bacteria that transform nutrients into less toxic forms for both fish and plants. Bacteria biofloc does the same thing, but researchers have found that the mixture of algae and bacteria is even more effective, at least in a lab setting.
“We want to know if this holds true in actual aquaponics systems,” he said.
Coupled aquaponics, meanwhile, means there is recirculation of water between the fish tank and the plant bed (and back again). Decoupled means water flows in one direction: from fish to plants but not back again. “Our project looks at both of these design choices, both independently and in combination,” Higgins said.
The test systems will be operated by high school students in east Alabama after hands-on training in a synergistic school-university partnership.
“Our team has extensive experience conducting research on aquaponics systems and algal-bacterial treatment of waste, and it engages frequently in educational and outreach programs with novice users,” he said.
The research project is significant because it’s expected to resolve persistent challenges that have hindered aquaponics adoption to date, Higgins said.
Integrating algae into decoupled biofloc production “has great promise to resolve microbial stability and pathogen concerns,” he said. “Moreover, our improved understanding of these microbial dynamics in aquaponics can translate broadly to other areas of aquaculture, nutrient recovery and waste management. An improved understanding of how design choices impact user experience can translate to research on other scalable food production technologies.”
The project will also lead enhance the education of high school student participants who live in low-income communities with limited food access. “Approximately 225 students will engage in hands-on learning by operating the aquaponics systems, allowing them to learn and apply knowledge of agriculture, biology, chemistry, nutrition and engineering,” Higgins said.
“This is important because these students are the future of sustainable food production: The skills they learn extend to a wide range of career and education pathways. We expect that reaching them in their formative years will result in measurable changes in self-perceptions regarding STEM topics, which will be assessed through survey instruments.”
This article has been edited and condensed from the original version appearing on the Auburn University website.
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