Aquaponics is a fascinating example of a modern agricultural biotechnology with roots that extend deeply into the past. Numerous historical examples, ranging from the Aztecs to thirteenth century Chinese, demonstrate common practices involving aquaponics-like enterprises. Modern greenhouses often contain precisely-engineered systems that delicately exploit the nitrogen cycle and produce large quantities of organically grown produce and fish. Remarkably, such operations use as little as 2% of the water of more typical agricultural practices and produce nearly twice as much food. For good measure, this food is grown without antibiotics or pesticides, tends to be nutritionally dense and can be grown in the so-called “food deserts” of the world where traditional agricultural would be difficult or even impossible.
So what is aquaponics? Simply put, it is a hybrid approach between aquaculture, the practice of rearing fish and other aquatic organisms for food and other applications and hydroponics, an agricultural approach where plants grow in nutrient-dense water instead of soil. Even though the plants and the fish are the most obvious participants in aquaponics systems, the true stars of the show are the bacteria, which chemically modify the nitrogen-based components of the water, thereby making it possible to keep both the fish and the plants alive.
Briefly, a typical aquaponics system works as follows. A relatively high density of fish eats, swims and produces waste, the primary component of which is nitrogenous ammonia. This ammonia, if allowed to rise to particularly high concentrations, would kill the fish and that would be that. Instead, the ammonia-containing water flows into a biofilter where nitrifying bacteria are more than happy to chemically convert this otherwise toxic ammonia into plant-friendly nitrates, via a two-step process. These nitrates represent a major component of both organic and fossil fuel-based fertilizers and when the water flows to the region where the plants are, they readily take up this important nutrient, thus supporting their own growth and removing nitrogen-based chemicals from the water. As such, they essentially detoxify the previously ammonia heavy water for the fish and then the cycle repeats over and over again.
While this setup might seem to be incredibly clever, at its essence, it is nothing more than a technological application of the nitrogen cycle, which occurs in nature in a similar fashion all around us and all the time. Because no soil is used in an aquaponics operation, the potential exists to establish such operations anywhere there is available electricity. This includes greenhouses in the middle of the desert (perhaps supported with solar panels), abandoned warehouses in the middle of an urban area, Because the plant roots are already submerged in water, no widespread irrigation is necessary, thereby leading to significant water savings. Lastly, because the roots have immediate access to nutrients, they don’t sprawl in various directions like they do in traditional agriculture. Therefore, the plants can grow in double the density compared to traditional agricultural practices.
I (and many others) see aquaponics as one of those amazing opportunities to both improve the world and improve one’s bottom line. Food deserts are abundant and many people who live in or near them often live a life of malnourishment. By establishing aquaponics operations in poor urban areas, for example, much of this type of challenge can be rectified. Sustainability conscious entrepreneurs could very well thrive providing nutrient-dense produce for people who might not have easy access to nutritious food that many people take for granted. This gap in the marketplace can be filled to the mutual benefit of both consumers and entrepreneurs.