Aquaponics: a new breed of sustainable farmers + social justice activists

Aquaponics in action!

Monday I discussed the ways climate change, GMO crops and overpopulation are threatening our food security, and I mentioned that aquaponics is in many ways the perfect solution to this problem.  Aquaponics is a system of aquaculture in which the waste produced by farmed fish or other aquatic animals supplies nutrients for plants grown hydroponically, which in turn purify the water.  It is gaining considerable attention lately as a serious sustainable farming practice with the potential of solving many of the problems that we face in the future, such as climate change, depleted soils, potable water, fossil fuel shortages and urban growth.

There are many different avenues to explore in aquaponics, such as its use in agri-aquaculture techniques, remediation of aquaculture effluents and other waste-water clean-up initiatives, as an integrated step in the production of renewable energy, as well as a specialty niche for urban/local food production markets in the U.S. and abroad.

Commercial-scale aquaponics has the potential of being the perfect “People, Planet and Profit” triple bottom line business, by providing healthy food to its community, reducing the ecological footprint of agriculture, and contributing to the strength and economic growth of its community.


Most sustainable agriculture practices, like aquaponics, mimic natural ecosystems.  An ecosystem is defined as a complex community of organisms interacting with each other and with their physical environment.  Food supplies are dependent on healthy interdependent relationships between organisms within ecosystems.  Interactions between plants, livestock, insects, soil bacteria, and fungi are essential for the production of food, as are optimal climate conditions, the fertility of our soil, and freshwater availability.

For example, the balanced nature of ecosystems in organic farming has been shown to support a greater variety of insects than in conventional farming, preventing any one pest from dominating and potentially destroying crops.  Organic farming also uses natural ecosystems to generate plant fertilizers, by using composted organic matter (i.e. manure and food waste broken down via microbes, insects and worms).

In aquaponic farming practices, organic matter in the form of fish waste is also converted into nutrients by microbes (and sometimes worms) and is used to fertilize the plants as well.

Figure 1. Aquaponic mechanical and biochemical system. Aquaponics is a closed-looped system that is similar to a wetland in that plants filter the water to keep fish healthy and in turn the fish effluent (waste) acts as a natural fertilizer for plant growth.
Figure 1. Aquaponic mechanical and biochemical system. Aquaponics is a closed-looped system that is similar to a wetland, in that plants filter the water to keep fish healthy, and, in turn, the fish effluent (waste) acts as a natural fertilizer for plant growth.


As shown in Figure 1 above, fish are raised in water tanks, connected to media-filled or hydroponic grow beds.  The fish tank water is pumped into the plant beds, where the ammonia waste is converted by bacteria (bound to the media substrate) into nitrates, which are absorbed by the plants and used as fertilizer.

This natural process results in clean water being recycled back into the fish tank.  The only inputs are the electricity to run the pump (and perhaps heaters & aerators) and the fish food.

The top 10 advantages that Aquaponic farming offers over other conventional farming practices:

  1. Aquaponics (unlike hydroponic & aquaculture practices) requires no fertilizer or chemicals, and there is no need to dispose of the toxic fish waste.  Instead, fish waste becomes a rich fertilizer resource.FYI: Chemical fertilizer production contributes to 33% of green-house gases, consumes 2% of the world’s energy production, and has long-term adverse impact on soil organisms and productivity.  Fish waste from aquaculture practices also contributes to carbon emissions and can be toxic to our environment.
  2. Aquaponics uses 90% less water for the same amount of produce than is required for conventional crops.FYI: Less than 1% of the world’s fresh water (~0.007% of all water on earth) is accessible for direct human use, and agriculture is responsible for 80-90 % of this total water used globally! It is predicted that fresh water will be a critical limiting resource for many regions in the near future!
  3. Aquaponics reduces fish species depletion and grows healthy fish that are free of mercury and radiation contamination.FYI: 75% of the world’s fisheries are currently depleted! Currently, 90% of our fish is imported, with 50% of that being farmed-raised, and only 2% of the market FDA-certified as safe for consumption!
  4. Aquaponic systems can also grow “natural’ plant food for your fish, making them healthier than corn- or soy-fed farm-raised fish.FYI: By growing fish on plant-based natural “fish” feed you will increase their Omega-3 fatty acid content, an essential nutrient that is lacking in most American diets. Not only will growing your own plant-based fish feed improve your health, it is environmentally friendly, since most commercial fish feed is made from wild-caught fish, with corn- or soy-based filler!
  5. Aquaponics can be performed in a relatively small place (indoors or outdoors) and requires no land (soil) and therefore is insensitive to flooding, drought, soil nutrient problems, or soil-borne diseases.FYI: There are more than 240 “friendly” micro-organisms in an aquaponic ecosystem that act as microscopic defenders, protecting the plants and fish from invading pathogenic organisms.  This is why Aquaponic systems are more pathogen-free and healthier than other food-growing systems, including hydroponics!
  6. Aquaponics is ideal for local food production, urban farming, and food desert sites, since no farm land is required, eliminating the need to add preservatives that are required for long distance transportation, and decreasing the dependency of fossil fuels for food delivery.FYI: Conventional agriculture is the single largest contributor of greenhouse gas emissions, contributed by the petroleum used in production and transportation, and by the nitrous oxide, carbon dioxide and methane released from over-fertilization.FYI: 1/5 of fossil fuels in the U.S. are currently used for conventional agricultural practices and food delivery, and aquaculture is the third largest domestic import in the U.S. (imagine the implication of local aquaponic food markets on these needs!)
  7. Aquaponics allows you to grow ‘safe,’ chemical-free, genetically-unmodified, organic food, and to lessen your carbon footprint, which will save you money at the market and the gas pump (supply and demand)!
  8. Aquaponics is weed-free, has low pest management, and requires no bending over to garden – so it’s physically-challenged friendly!
  9. Aquaponics is the perfect hands-on, project-based learning tool to teach students basic biology, chemistry, mathematics, engineering and business skills, while also offering students a practical side of learning, by teaching them how to become self-reliant and environmental responsible as they grow their own food in a sustainable way.
  10. Aquaponics is just plain FUN! When you can capture people’s imagination, you are given the opportunity to teach them.

Considering these facts, you can see that aquaponics offers many advantages as a more sustainable eco-friendly farming practice than conventional farming and hydroponics techniques.  There are associated energy costs with running aquaponic systems (pumps, aerators, and/or heaters); however, these costs can be potentially offset by the use of solar or wind energy.

A large scale aquaponics system at Lucky Clay Fresh in Norwood, NC. Photo by Brad Todd.

Future Challenges

Urban Aquaponics ventures have recently sprung up across the US, with most being small, single owner-operated businesses.  In most successful operations, selling the fish pays for the operational costs, and the plant sales drive the profits.

If one incorporated solar or wind power, there would be even more to gain financially.  Since success in aquaponic food production will ultimately depend on the knowledge base of the operator, teaching the farmer how to properly balance the ecosystem for optimal production is the linchpin in making aquaponics more productive and financially viable.

Basic research in aquaponics is still warranted, to optimize the production of high quality yields of fruits, vegetables, and fish crops, and market research is needed, to evaluate the economic feasibility of this sustainable farming technology. The results from these studies will not only help create opportunites for farmers to diversify their market in the plant and fish sector, but the food that they will produce may in fact be healthier for the consumer.

This article is part two of a two-part series on how aquaponics is a sustainable solution to many of today’s problems. Read part one here.

Aquaponics workshop Saturday!

Learn more about aquaponics from Tinker-Kulberg, in person, at her Aquaponics Workshop, taught along with Mike Yablonski, Ph.D, this Sunday, Oct. 18, from 10:00 AM – 3:00 PM.