The quickest way to explain aquaponic is to say that it is a combination of aquaculture and hydroponics. The next step is to explain what the latter two terms mean. First, aquaculture is a method to raise aquatic animals which include snails, crayfish, prawns and other fish) in glass tanks. Second, hydroponics is a way to grow plants in water. Combine these two, and you get aquaponics. It is a symbiotic environment where both entities, in this case, the aquatic animals and the plants, benefit from each other.
In a standard aquaculture setting, the feces of the animals accumulate in the water which leads to an increase in toxicity. To avoid this, the aquaculture is placed in a hydroponic system, creating an aquaponic system. The toxic excrements of the animals are processed by the bacteria, and then the plants can use the nitrates created by the process as nutrients. Of course, the water is purified by the whole procedure and returned to the aquaculture system.
History of aquaponics
There is evidence that Aztec tribes practice a rudimentary form of aquaponics. They created agricultural islands which they named chinampas. These were islands where plants were cultivated in shallow waters of lakes. All of the wastewater from the cities was directed towards these islands via a system of canals so that the plants were irrigated.
Another early example of an aquaponic system are the rice fields of East Asia. Paddy fields combined with fish species like eels, carps, and loaches, produced excellent results.
Modern aquaponics is mostly based on the works of the New York Alchemy Institute. One of the leading scientists of aquaponics is Dr. Mark McMurtry. Other institutions based their research on the accomplishments of Dr. McMurtry and the Institute and followed up with new ideas, one example being Vladislav Davidzon and his research of permaculture.
For an aquaponic system to function properly, different live components need to cooperate successfully. Every aquaponic system consists of plants, fish, and bacteria. Fish can be substituted with other aquatic creatures.
Plants suitable for aquaponic systems are abundant, but careful selection is obligatory. Fish of different maturity and stocking density demand different plants for best results. The more fish there are in the system, the more plants are needed to filter the excrement. Common green leaf vegetables such as lettuce, Chinese cabbage, basil, spinach, and watercress suit aquaponics well. Some plants only work well with mature aquaponic systems, and these are tomatoes and cucumbers, for example.
When it comes to fish, the most common aquatic animals suitable for aquaponic systems, the most often used are freshwater fish because they can tolerate crowding. Crayfish and prawns are a secondary choice. Saltwater fish work in separate aquaponic systems called saltwater aquaponics. Most popular fish for both home and large-scale commercial projects is the tilapia.
Bacterial species which populate aquaponic systems are the Nitrosomas and the Nitrobacter. The former turn ammonia into nitrites and the latter convert nitrites into nitrates. Thanks to this process, the toxicity of the system is reduced, and plants can use the nitrate compounds as nourishment.