Microbes & Fish Poop: Students explore urban farming through aquaponics

At Port of Los Angeles High School (POLA), a small group of students has gathered near the edge of campus – beyond the main buildings and sheds, tucked between the asphalt and a high concrete wall, a patch of dirt has been turned into a small garden. A group of about 15 teenagers stand around chatting and hastily finishing their lunches. They are eager to get their hands dirty, but today they will not be touching any dirt. Today, they are planting vegetables and transferring fish into a new aquaponic tank. It is the latest addition to the carbon-free education garden the students are creating.

Aquaponics is a model of sustainable and organic urban farming that uses very little water, no soil, and produces no waste. The closed system pumps water in a continuous loop from the fish tank, to the plants, and back to the fish tank. The waste from the fish is converted by microbes into nutrients that fertilize the plants, and the plants, in turn, clean the water as it returns to the fish tank.

“You don’t have to live in Kansas to grow your own food,” says Dean Zrucky, AP Environmental Science teacher at POLA. “The students are really motivated to learn about this.”

Students are learning about where food comes from, our changing climate, the ongoing drought in California, and what this means for water resources. In this context, how do we grow food with limited water supplies? How can we produce enough food for a growing urban population with our changing climate? Aquaponics can be useful in many ‘fresh food deserts’ in our city that don’t have easy or consistent access to fresh food, and the systems work in homes that don’t have yard space for a garden.

POLA is part of the Food for Thought program, a partnership between USC Sea Grant, the USC Wrigley Institute, and Our Foods. The unique program weaves together expertise on aquaponic tank systems with current university level research and curriculum planning for the new Next Generation Science Standards. The platform provides a project-based learning approach where students are responsible for maintaining the tank systems and the health of the fish and plants. In addition to the core aquatic science and engineering topics they must understand to succeed, students are also exposed to the fields of agriculture and aquaculture fisheries as career options.

“This is an emerging field of science, with tremendous classroom application opportunities,” says Linda Chilton, education programs manager with USC Sea Grant, who is writing, testing, and refining the program’s curriculum.

Lettuce, kale, spinach, mint, chard… students carefully take each seedling and rinse off all the dirt from the roots. They then lay the roots on a dark porous surface that looks like shredded plastic. It is actually made from recycled plastic bottles and the nooks and crannies provide great surface area for bacteria to grow. The young plants then get pushed into hollow tubes called zip-grow towers until only bright green leaves are visible. It doesn’t take long for the students to begin arranging the plants based on type and color.

“This isn’t just farming,” says Joshua Renfro, program coordinator with Our Foods. “This is art.”

Finally, the towers are attached to the fish tank, and students test the water quality and transfer several fish into their new home. The tank system is working!

Food for Thought is funded by the Boeing Foundation and provides training, curriculum, supplies, and materials including an aquaponic tank system, fish, and plants. The program is currently in eight public schools around Los Angeles. Learn more.