Aquaponics is a symbiotic combination of hydroponics (method of growing plants in water, using mineral nutrient solutions, without soil) and aquaculture (farming of aquatic organisms), or the process of growing plants and fish together in one integrated system that relies on the biotic relationship between fish and bacteria. Fish waste is converted to forms useable by plants by a healthy population of bacteria. For instance, ammonia (a form of nitrogen toxic to fish) is first converted to nitrites by bacteria and then to nitrates by another type of bacteria. Since water is a nutrient delivery system, these nitrates are then taken up and used by the plants, returning clean water to the fish. Essentially the plants filter the water for the fish and gain biomass at the same time, all in one sustainable ecosystem. In addition to nitrogen, phosphorous and potassium make up the three primary plant nutrients. Since these systems rely on natural processes, there is no need for chemically derived fertilizers or nutrients. This results in an efficient system with no environmentally hazardous waste being produced.
The commercial industry of aquaponics is rapidly growing; however, these systems can easily be established in backyards or bright rooms, by anyone. Home-based aquaponic systems can vary greatly in size. Outdoor systems may utilize a small area of a backyard, existing space around a pond, or even an entire backyard. Indoor systems may be set-up with plastic tubs near bright windows to minimize the usage of plant lights, or even added on to an indoor aquarium. Both outdoor and indoor aquaponic systems can provide fresh, local food for a single person, a family, or even multiple households. The amount of food and fish produced only depend on the size of the working system.
There are many benefits to choosing aquaponic systems over traditional growing
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methods. The relationships between the fish, bacteria, and plants keep the water quality high while allowing the plants to gain biomass. Water use is greatly reduced compared to traditional gardening by circulating it through the system, rather than allowing it to percolate down to the ground water or run-off in the surface water. Thus, there are no concerns regarding soil erosion and run-off with aquaponics. Evaporation from the substrate (soil in normal gardening) is also minimized by the circulating water and nutrient delivery system. Only water loss through leaf transpiration and harvesting is comparable to what is seen in soil-based plant production. Since the fish waste provides nutrients to the plants, the use of chemical fertilizers and nutrients is also greatly reduced. Pesticide and herbicide use is eliminated to sustain the fish. If an additional greenhouse is used to cover the system, fresh produce and fish can be grown nearly year-round in most climates. The water in a well functioning aquaponic system never needs to be replaced, unlike in hydroponic systems where nutrient imbalances occur over time. The chemicals that build up in hydroponics systems can also pollute waterways if not disposed of properly. Aquaponics systems also avoid the toxicity problem of built up nitrites seen in aquaculture systems. The nitrites are converted into nitrates by bacterial populations in established aquaponic systems, which the plants take up and utilized as their nutrient source. Aquaponics systems rely on natural processes between fish, bacteria, and plants, to provide many benefits compared to other methods of growing food.
